An Iris Segmentation Algorithm based on Edge Orientation for Off-angle Iris Recognition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karakaya, Mahmut; Barstow, Del R; Santos-Villalobos, Hector J

Iris recognition is known as one of the most accurate and reliable biometrics. However, the accuracy of iris recognition systems depends on the quality of data capture and is negatively affected by several factors such as angle, occlusion, and dilation. In this paper, we present a segmentation algorithm for off-angle iris images that uses edge detection, edge elimination, edge classification, and ellipse fitting techniques. In our approach, we first detect all candidate edges in the iris image by using the canny edge detector; this collection contains edges from the iris and pupil boundaries as well as eyelash, eyelids, iris texturemore » etc. Edge orientation is used to eliminate the edges that cannot be part of the iris or pupil. Then, we classify the remaining edge points into two sets as pupil edges and iris edges. Finally, we randomly generate subsets of iris and pupil edge points, fit ellipses for each subset, select ellipses with similar parameters, and average to form the resultant ellipses. Based on the results from real experiments, the proposed method shows effectiveness in segmentation for off-angle iris images.« less

Nonintrusive iris image acquisition system based on a pan-tilt-zoom camera and light stripe projection

NASA Astrophysics Data System (ADS)

Yoon, Soweon; Jung, Ho Gi; Park, Kang Ryoung; Kim, Jaihie

2009-03-01

Although iris recognition is one of the most accurate biometric technologies, it has not yet been widely used in practical applications. This is mainly due to user inconvenience during the image acquisition phase. Specifically, users try to adjust their eye position within small capture volume at a close distance from the system. To overcome these problems, we propose a novel iris image acquisition system that provides users with unconstrained environments: a large operating range, enabling movement from standing posture, and capturing good-quality iris images in an acceptable time. The proposed system has the following three contributions compared with previous works: (1) the capture volume is significantly increased by using a pan-tilt-zoom (PTZ) camera guided by a light stripe projection, (2) the iris location in the large capture volume is found fast due to 1-D vertical face searching from the user's horizontal position obtained by the light stripe projection, and (3) zooming and focusing on the user's irises at a distance are accurate and fast using the estimated 3-D position of a face by the light stripe projection and the PTZ camera. Experimental results show that the proposed system can capture good-quality iris images in 2.479 s on average at a distance of 1.5 to 3 m, while allowing a limited amount of movement by the user.

Noisy Ocular Recognition Based on Three Convolutional Neural Networks

PubMed Central

Lee, Min Beom; Hong, Hyung Gil; Park, Kang Ryoung

2017-01-01

In recent years, the iris recognition system has been gaining increasing acceptance for applications such as access control and smartphone security. When the images of the iris are obtained under unconstrained conditions, an issue of undermined quality is caused by optical and motion blur, off-angle view (the user’s eyes looking somewhere else, not into the front of the camera), specular reflection (SR) and other factors. Such noisy iris images increase intra-individual variations and, as a result, reduce the accuracy of iris recognition. A typical iris recognition system requires a near-infrared (NIR) illuminator along with an NIR camera, which are larger and more expensive than fingerprint recognition equipment. Hence, many studies have proposed methods of using iris images captured by a visible light camera without the need for an additional illuminator. In this research, we propose a new recognition method for noisy iris and ocular images by using one iris and two periocular regions, based on three convolutional neural networks (CNNs). Experiments were conducted by using the noisy iris challenge evaluation-part II (NICE.II) training dataset (selected from the university of Beira iris (UBIRIS).v2 database), mobile iris challenge evaluation (MICHE) database, and institute of automation of Chinese academy of sciences (CASIA)-Iris-Distance database. As a result, the method proposed by this study outperformed previous methods. PMID:29258217

Integrating image quality in 2nu-SVM biometric match score fusion.

PubMed

Vatsa, Mayank; Singh, Richa; Noore, Afzel

2007-10-01

This paper proposes an intelligent 2nu-support vector machine based match score fusion algorithm to improve the performance of face and iris recognition by integrating the quality of images. The proposed algorithm applies redundant discrete wavelet transform to evaluate the underlying linear and non-linear features present in the image. A composite quality score is computed to determine the extent of smoothness, sharpness, noise, and other pertinent features present in each subband of the image. The match score and the corresponding quality score of an image are fused using 2nu-support vector machine to improve the verification performance. The proposed algorithm is experimentally validated using the FERET face database and the CASIA iris database. The verification performance and statistical evaluation show that the proposed algorithm outperforms existing fusion algorithms.

Limbus Impact on Off-angle Iris Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karakaya, Mahmut; Barstow, Del R; Santos-Villalobos, Hector J

The accuracy of iris recognition depends on the quality of data capture and is negatively affected by several factors such as angle, occlusion, and dilation. Off-angle iris recognition is a new research focus in biometrics that tries to address several issues including corneal refraction, complex 3D iris texture, and blur. In this paper, we present an additional significant challenge that degrades the performance of the off-angle iris recognition systems, called the limbus effect . The limbus is the region at the border of the cornea where the cornea joins the sclera. The limbus is a semitransparent tissue that occludes amore » side portion of the iris plane. The amount of occluded iris texture on the side nearest the camera increases as the image acquisition angle increases. Without considering the role of the limbus effect, it is difficult to design an accurate off-angle iris recognition system. To the best of our knowledge, this is the first work that investigates the limbus effect in detail from a biometrics perspective. Based on results from real images and simulated experiments with real iris texture, the limbus effect increases the hamming distance score between frontal and off-angle iris images ranging from 0.05 to 0.2 depending upon the limbus height.« less

Gaze Estimation for Off-Angle Iris Recognition Based on the Biometric Eye Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karakaya, Mahmut; Barstow, Del R; Santos-Villalobos, Hector J

Iris recognition is among the highest accuracy biometrics. However, its accuracy relies on controlled high quality capture data and is negatively affected by several factors such as angle, occlusion, and dilation. Non-ideal iris recognition is a new research focus in biometrics. In this paper, we present a gaze estimation method designed for use in an off-angle iris recognition framework based on the ANONYMIZED biometric eye model. Gaze estimation is an important prerequisite step to correct an off-angle iris images. To achieve the accurate frontal reconstruction of an off-angle iris image, we first need to estimate the eye gaze direction frommore » elliptical features of an iris image. Typically additional information such as well-controlled light sources, head mounted equipment, and multiple cameras are not available. Our approach utilizes only the iris and pupil boundary segmentation allowing it to be applicable to all iris capture hardware. We compare the boundaries with a look-up-table generated by using our biologically inspired biometric eye model and find the closest feature point in the look-up-table to estimate the gaze. Based on the results from real images, the proposed method shows effectiveness in gaze estimation accuracy for our biometric eye model with an average error of approximately 3.5 degrees over a 50 degree range.« less

Technical issues for the eye image database creation at distance

NASA Astrophysics Data System (ADS)

Oropesa Morales, Lester Arturo; Maldonado Cano, Luis Alejandro; Soto Aldaco, Andrea; García Vázquez, Mireya Saraí; Zamudio Fuentes, Luis Miguel; Rodríguez Vázquez, Manuel Antonio; Pérez Rosas, Osvaldo Gerardo; Rodríguez Espejo, Luis; Montoya Obeso, Abraham; Ramírez Acosta, Alejandro Álvaro

2016-09-01

Biometrics refers to identify people through their physical characteristics or behavior such as fingerprints, face, DNA, hand geometries, retina and iris patterns. Typically, the iris pattern is to acquire in short distance to recognize a person, however, in the past few years is a challenge identify a person by its iris pattern at certain distance in non-cooperative environments. This challenge comprises: 1) high quality iris image, 2) light variation, 3) blur reduction, 4) specular reflections reduction, 5) the distance from the acquisition system to the user, and 6) standardize the iris size and the density pixel of iris texture. The solution of the challenge will add robustness and enhance the iris recognition rates. For this reason, we describe the technical issues that must be considered during iris acquisition. Some of these considerations are the camera sensor, lens, the math analysis of depth of field (DOF) and field of view (FOV) for iris recognition. Finally, based on this issues we present experiment that show the result of captures obtained with our camera at distance and captures obtained with cameras in very short distance.

The Infrared Imaging Spectrograph (IRIS) for TMT: multi-tiered wavefront measurements and novel mechanical design

NASA Astrophysics Data System (ADS)

Dunn, Jennifer; Andersen, David; Chapin, Edward; Reshetov, Vlad; Wierzbicki, Ramunas; Herriot, Glen; Chalmer, Dean; Isbrucker, Victor; Larkin, James E.; Moore, Anna M.; Suzuki, Ryuji

2016-08-01

The InfraRed Imaging Spectrograph (IRIS) will be the first light adaptive optics instrument on the Thirty Meter Telescope (TMT). IRIS is being built by a collaboration between Caltech, the University of California, NAOJ and NRC Herzberg. In this paper we present novel aspects of the Support Structure, Rotator and On-Instrument Wavefront Sensor systems being developed at NRC Herzberg. IRIS is suspended from the bottom port of the Narrow Field Infrared Adaptive Optics System (NFIRAOS), and provides its own image de-rotation to compensate for sidereal rotation of the focal plane. This arrangement is a challenge because NFIRAOS is designed to host two other science instruments, which imposes strict mass requirements on IRIS. As the mechanical design of all elements has progressed, we have been tasked with keeping the instrument mass under seven tonnes. This requirement has resulted in a mass reduction of 30 percent for the support structure and rotator compared to the most recent IRIS designs. To accomplish this goal, while still being able to withstand earthquakes, we developed a new design with composite materials. As IRIS is a client instrument of NFIRAOS, it benefits from NFIRAOS's superior AO correction. IRIS plays an important role in providing this correction by sensing low-order aberrations with three On-Instrument Wavefront Sensors (OIWFS). The OIWFS consists of three independently positioned natural guide star wavefront sensor probe arms that patrol a 2-arcminute field of view. We expect tip-tilt measurements from faint stars within the IRIS imager focal plane will further stabilize the delivered image quality. We describe how the use of On-Detector Guide Windows (ODGWs) in the IRIS imaging detector can be incorporated into the AO correction. In this paper, we present our strategies for acquiring and tracking sources with this complex AO system, and for mitigating and measuring the various potential sources of image blur and misalignment due to properties of the mechanical structure and interfaces.

IrisDenseNet: Robust Iris Segmentation Using Densely Connected Fully Convolutional Networks in the Images by Visible Light and Near-Infrared Light Camera Sensors

PubMed Central

Arsalan, Muhammad; Naqvi, Rizwan Ali; Kim, Dong Seop; Nguyen, Phong Ha; Owais, Muhammad; Park, Kang Ryoung

2018-01-01

The recent advancements in computer vision have opened new horizons for deploying biometric recognition algorithms in mobile and handheld devices. Similarly, iris recognition is now much needed in unconstraint scenarios with accuracy. These environments make the acquired iris image exhibit occlusion, low resolution, blur, unusual glint, ghost effect, and off-angles. The prevailing segmentation algorithms cannot cope with these constraints. In addition, owing to the unavailability of near-infrared (NIR) light, iris recognition in visible light environment makes the iris segmentation challenging with the noise of visible light. Deep learning with convolutional neural networks (CNN) has brought a considerable breakthrough in various applications. To address the iris segmentation issues in challenging situations by visible light and near-infrared light camera sensors, this paper proposes a densely connected fully convolutional network (IrisDenseNet), which can determine the true iris boundary even with inferior-quality images by using better information gradient flow between the dense blocks. In the experiments conducted, five datasets of visible light and NIR environments were used. For visible light environment, noisy iris challenge evaluation part-II (NICE-II selected from UBIRIS.v2 database) and mobile iris challenge evaluation (MICHE-I) datasets were used. For NIR environment, the institute of automation, Chinese academy of sciences (CASIA) v4.0 interval, CASIA v4.0 distance, and IIT Delhi v1.0 iris datasets were used. Experimental results showed the optimal segmentation of the proposed IrisDenseNet and its excellent performance over existing algorithms for all five datasets. PMID:29748495

IrisDenseNet: Robust Iris Segmentation Using Densely Connected Fully Convolutional Networks in the Images by Visible Light and Near-Infrared Light Camera Sensors.

PubMed

Arsalan, Muhammad; Naqvi, Rizwan Ali; Kim, Dong Seop; Nguyen, Phong Ha; Owais, Muhammad; Park, Kang Ryoung

2018-05-10

The recent advancements in computer vision have opened new horizons for deploying biometric recognition algorithms in mobile and handheld devices. Similarly, iris recognition is now much needed in unconstraint scenarios with accuracy. These environments make the acquired iris image exhibit occlusion, low resolution, blur, unusual glint, ghost effect, and off-angles. The prevailing segmentation algorithms cannot cope with these constraints. In addition, owing to the unavailability of near-infrared (NIR) light, iris recognition in visible light environment makes the iris segmentation challenging with the noise of visible light. Deep learning with convolutional neural networks (CNN) has brought a considerable breakthrough in various applications. To address the iris segmentation issues in challenging situations by visible light and near-infrared light camera sensors, this paper proposes a densely connected fully convolutional network (IrisDenseNet), which can determine the true iris boundary even with inferior-quality images by using better information gradient flow between the dense blocks. In the experiments conducted, five datasets of visible light and NIR environments were used. For visible light environment, noisy iris challenge evaluation part-II (NICE-II selected from UBIRIS.v2 database) and mobile iris challenge evaluation (MICHE-I) datasets were used. For NIR environment, the institute of automation, Chinese academy of sciences (CASIA) v4.0 interval, CASIA v4.0 distance, and IIT Delhi v1.0 iris datasets were used. Experimental results showed the optimal segmentation of the proposed IrisDenseNet and its excellent performance over existing algorithms for all five datasets.

An investigation of kV CBCT image quality and dose reduction for volume-of-interest imaging using dynamic collimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons, David, E-mail: david.parsons@dal.ca, E-mail: james.robar@cdha.nshealth.ca; Robar, James L., E-mail: david.parsons@dal.ca, E-mail: james.robar@cdha.nshealth.ca

2015-09-15

Purpose: The focus of this work was to investigate the improvements in image quality and dose reduction for volume-of-interest (VOI) kilovoltage-cone beam CT (CBCT) using dynamic collimation. Methods: A prototype iris aperture was used to track a VOI during a CBCT acquisition. The current aperture design is capable of 1D translation as a function of gantry angle and dynamic adjustment of the iris radius. The aperture occupies the location of the bow-tie filter on a Varian On-Board Imager system. CBCT and planar image quality were investigated as a function of aperture radius, while maintaining the same dose to the VOI,more » for a 20 cm diameter cylindrical water phantom with a 9 mm diameter bone insert centered on isocenter. Corresponding scatter-to-primary ratios (SPR) were determined at the detector plane with Monte Carlo simulation using EGSnrc. Dose distributions for various sizes VOI were modeled using a dynamic BEAMnrc library and DOSXYZnrc. The resulting VOI dose distributions were compared to full-field distributions. Results: SPR was reduced by a factor of 8.4 when decreasing iris diameter from 21.2 to 2.4 cm (at isocenter). Depending upon VOI location and size, dose was reduced to 16%–90% of the full-field value along the central axis plane and down to 4% along the axis of rotation, while maintaining the same dose to the VOI compared to full-field techniques. When maintaining constant dose to the VOI, this change in iris diameter corresponds to a factor increase of approximately 1.6 in image contrast and a factor decrease in image noise of approximately 1.2. This results in a measured gain in contrast-to-noise ratio by a factor of approximately 2.0. Conclusions: The presented VOI technique offers improved image quality for image-guided radiotherapy while sparing the surrounding volume of unnecessary dose compared to full-field techniques.« less

Test of the Practicality and Feasibility of EDoF-Empowered Image Sensors for Long-Range Biometrics.

PubMed

Hsieh, Sheng-Hsun; Li, Yung-Hui; Tien, Chung-Hao

2016-11-25

For many practical applications of image sensors, how to extend the depth-of-field (DoF) is an important research topic; if successfully implemented, it could be beneficial in various applications, from photography to biometrics. In this work, we want to examine the feasibility and practicability of a well-known "extended DoF" (EDoF) technique, or "wavefront coding," by building real-time long-range iris recognition and performing large-scale iris recognition. The key to the success of long-range iris recognition includes long DoF and image quality invariance toward various object distance, which is strict and harsh enough to test the practicality and feasibility of EDoF-empowered image sensors. Besides image sensor modification, we also explored the possibility of varying enrollment/testing pairs. With 512 iris images from 32 Asian people as the database, 400-mm focal length and F/6.3 optics over 3 m working distance, our results prove that a sophisticated coding design scheme plus homogeneous enrollment/testing setups can effectively overcome the blurring caused by phase modulation and omit Wiener-based restoration. In our experiments, which are based on 3328 iris images in total, the EDoF factor can achieve a result 3.71 times better than the original system without a loss of recognition accuracy.

VASIR: An Open-Source Research Platform for Advanced Iris Recognition Technologies.

PubMed

Lee, Yooyoung; Micheals, Ross J; Filliben, James J; Phillips, P Jonathon

2013-01-01

The performance of iris recognition systems is frequently affected by input image quality, which in turn is vulnerable to less-than-optimal conditions due to illuminations, environments, and subject characteristics (e.g., distance, movement, face/body visibility, blinking, etc.). VASIR (Video-based Automatic System for Iris Recognition) is a state-of-the-art NIST-developed iris recognition software platform designed to systematically address these vulnerabilities. We developed VASIR as a research tool that will not only provide a reference (to assess the relative performance of alternative algorithms) for the biometrics community, but will also advance (via this new emerging iris recognition paradigm) NIST's measurement mission. VASIR is designed to accommodate both ideal (e.g., classical still images) and less-than-ideal images (e.g., face-visible videos). VASIR has three primary modules: 1) Image Acquisition 2) Video Processing, and 3) Iris Recognition. Each module consists of several sub-components that have been optimized by use of rigorous orthogonal experiment design and analysis techniques. We evaluated VASIR performance using the MBGC (Multiple Biometric Grand Challenge) NIR (Near-Infrared) face-visible video dataset and the ICE (Iris Challenge Evaluation) 2005 still-based dataset. The results showed that even though VASIR was primarily developed and optimized for the less-constrained video case, it still achieved high verification rates for the traditional still-image case. For this reason, VASIR may be used as an effective baseline for the biometrics community to evaluate their algorithm performance, and thus serves as a valuable research platform.

VASIR: An Open-Source Research Platform for Advanced Iris Recognition Technologies

PubMed Central

Lee, Yooyoung; Micheals, Ross J; Filliben, James J; Phillips, P Jonathon

2013-01-01

The performance of iris recognition systems is frequently affected by input image quality, which in turn is vulnerable to less-than-optimal conditions due to illuminations, environments, and subject characteristics (e.g., distance, movement, face/body visibility, blinking, etc.). VASIR (Video-based Automatic System for Iris Recognition) is a state-of-the-art NIST-developed iris recognition software platform designed to systematically address these vulnerabilities. We developed VASIR as a research tool that will not only provide a reference (to assess the relative performance of alternative algorithms) for the biometrics community, but will also advance (via this new emerging iris recognition paradigm) NIST’s measurement mission. VASIR is designed to accommodate both ideal (e.g., classical still images) and less-than-ideal images (e.g., face-visible videos). VASIR has three primary modules: 1) Image Acquisition 2) Video Processing, and 3) Iris Recognition. Each module consists of several sub-components that have been optimized by use of rigorous orthogonal experiment design and analysis techniques. We evaluated VASIR performance using the MBGC (Multiple Biometric Grand Challenge) NIR (Near-Infrared) face-visible video dataset and the ICE (Iris Challenge Evaluation) 2005 still-based dataset. The results showed that even though VASIR was primarily developed and optimized for the less-constrained video case, it still achieved high verification rates for the traditional still-image case. For this reason, VASIR may be used as an effective baseline for the biometrics community to evaluate their algorithm performance, and thus serves as a valuable research platform. PMID:26401431

Real-time image-guided nasogastric feeding tube placement: A case series using Kangaroo with IRIS Technology in an ICU.

PubMed

Mizzi, Anna; Cozzi, Silvano; Beretta, Luigi; Greco, Massimiliano; Braga, Marco

2017-05-01

Pulmonary misplacement during the blind insertion of enteral feeding tubes is frequent, particularly in ventilated and neurologically impaired patients. This is probably the first clinical study using the Kangaroo Feeding Tube with IRIS technology (IRIS) which incorporates a camera designed to provide anatomic landmark visualization during insertion. The study aim was to evaluate IRIS performance during bedside gastric placement. This is the first prospective study to collect data on the use of IRIS. Twenty consecutive unconscious patients requiring enteral nutrition were recruited at a single center. IRIS placement was considered complete when a clear image of the gastric mucosa appeared. Correct placement was confirmed using a contrast-enhanced abdominal X-ray. To evaluate the device performance over time, the camera was activated every other day up to 17 d postplacement. In 7 (35%) patients, the trachea was initially visualized, requiring a second placement attempt with the same tube. The IRIS camera allowed recognition of the gastric mucosa in 18 (90%) patients. The esophagogastric junction was identified in one patient, while in a second patient the quality of visualization was poor. Contrast-enhanced X-ray confirmed the gastric placement of IRIS in all patients. IRIS allowed identification of gastric mucosa in 14 (70%) patients 3 d after placement. Performance progressively declined with time (P = 0.006, chi-square for trend). IRIS placement could have spared X-ray confirmation in almost all patients and prevented misplacement into the airway in about one third. Visualization quality needs to be improved, particularly after the first week. Copyright © 2016 Elsevier Inc. All rights reserved.

Iris Image Classification Based on Hierarchical Visual Codebook.

PubMed

Zhenan Sun; Hui Zhang; Tieniu Tan; Jianyu Wang

2014-06-01

Iris recognition as a reliable method for personal identification has been well-studied with the objective to assign the class label of each iris image to a unique subject. In contrast, iris image classification aims to classify an iris image to an application specific category, e.g., iris liveness detection (classification of genuine and fake iris images), race classification (e.g., classification of iris images of Asian and non-Asian subjects), coarse-to-fine iris identification (classification of all iris images in the central database into multiple categories). This paper proposes a general framework for iris image classification based on texture analysis. A novel texture pattern representation method called Hierarchical Visual Codebook (HVC) is proposed to encode the texture primitives of iris images. The proposed HVC method is an integration of two existing Bag-of-Words models, namely Vocabulary Tree (VT), and Locality-constrained Linear Coding (LLC). The HVC adopts a coarse-to-fine visual coding strategy and takes advantages of both VT and LLC for accurate and sparse representation of iris texture. Extensive experimental results demonstrate that the proposed iris image classification method achieves state-of-the-art performance for iris liveness detection, race classification, and coarse-to-fine iris identification. A comprehensive fake iris image database simulating four types of iris spoof attacks is developed as the benchmark for research of iris liveness detection.

Test of the Practicality and Feasibility of EDoF-Empowered Image Sensors for Long-Range Biometrics

PubMed Central

Hsieh, Sheng-Hsun; Li, Yung-Hui; Tien, Chung-Hao

2016-01-01

For many practical applications of image sensors, how to extend the depth-of-field (DoF) is an important research topic; if successfully implemented, it could be beneficial in various applications, from photography to biometrics. In this work, we want to examine the feasibility and practicability of a well-known “extended DoF” (EDoF) technique, or “wavefront coding,” by building real-time long-range iris recognition and performing large-scale iris recognition. The key to the success of long-range iris recognition includes long DoF and image quality invariance toward various object distance, which is strict and harsh enough to test the practicality and feasibility of EDoF-empowered image sensors. Besides image sensor modification, we also explored the possibility of varying enrollment/testing pairs. With 512 iris images from 32 Asian people as the database, 400-mm focal length and F/6.3 optics over 3 m working distance, our results prove that a sophisticated coding design scheme plus homogeneous enrollment/testing setups can effectively overcome the blurring caused by phase modulation and omit Wiener-based restoration. In our experiments, which are based on 3328 iris images in total, the EDoF factor can achieve a result 3.71 times better than the original system without a loss of recognition accuracy. PMID:27897976

The fast iris image clarity evaluation based on Tenengrad and ROI selection

NASA Astrophysics Data System (ADS)

Gao, Shuqin; Han, Min; Cheng, Xu

2018-04-01

In iris recognition system, the clarity of iris image is an important factor that influences recognition effect. In the process of recognition, the blurred image may possibly be rejected by the automatic iris recognition system, which will lead to the failure of identification. Therefore it is necessary to evaluate the iris image definition before recognition. Considered the existing evaluation methods on iris image definition, we proposed a fast algorithm to evaluate the definition of iris image in this paper. In our algorithm, firstly ROI (Region of Interest) is extracted based on the reference point which is determined by using the feature of the light spots within the pupil, then Tenengrad operator is used to evaluate the iris image's definition. Experiment results show that, the iris image definition algorithm proposed in this paper could accurately distinguish the iris images of different clarity, and the algorithm has the merit of low computational complexity and more effectiveness.

A gallery approach for off-angle iris recognition

NASA Astrophysics Data System (ADS)

Karakaya, Mahmut; Yoldash, Rashiduddin; Boehnen, Christopher

2015-05-01

It has been proven that hamming distance score between frontal and off-angle iris images of same eye differs in iris recognition system. The distinction of hamming distance score is caused by many factors such as image acquisition angle, occlusion, pupil dilation, and limbus effect. In this paper, we first study the effect of the angle variations between iris plane and the image acquisition systems. We present how hamming distance changes for different off-angle iris images even if they are coming from the same iris. We observe that increment in acquisition angle of compared iris images causes the increment in hamming distance. Second, we propose a new technique in off-angle iris recognition system that includes creating a gallery of different off-angle iris images (such as, 0, 10, 20, 30, 40, and 50 degrees) and comparing each probe image with these gallery images. We will show the accuracy of the gallery approach for off-angle iris recognition.

An effective approach for iris recognition using phase-based image matching.

PubMed

Miyazawa, Kazuyuki; Ito, Koichi; Aoki, Takafumi; Kobayashi, Koji; Nakajima, Hiroshi

2008-10-01

This paper presents an efficient algorithm for iris recognition using phase-based image matching--an image matching technique using phase components in 2D Discrete Fourier Transforms (DFTs) of given images. Experimental evaluation using CASIA iris image databases (versions 1.0 and 2.0) and Iris Challenge Evaluation (ICE) 2005 database clearly demonstrates that the use of phase components of iris images makes possible to achieve highly accurate iris recognition with a simple matching algorithm. This paper also discusses major implementation issues of our algorithm. In order to reduce the size of iris data and to prevent the visibility of iris images, we introduce the idea of 2D Fourier Phase Code (FPC) for representing iris information. The 2D FPC is particularly useful for implementing compact iris recognition devices using state-of-the-art Digital Signal Processing (DSP) technology.

Application synergies between the NASA Pre- Aerosol Cloud and ocean Ecosystem (PACE) and Hyperspectral Infrared Imager (HyspIRI) missions

NASA Astrophysics Data System (ADS)

Lee, C. M.; Omar, A. H.; Hook, S. J.; Tzortziou, M.; Luvall, J. C.; Turner, W. W.

2016-02-01

Observations from the Pre-Aerosol Cloud and ocean Ecosystem (PACE) and Hyperspectral InfraRed Imager (HyspIRI) satellite missions are highly complementary and have the potential to significantly advance understanding of various science and applications challenges in the ocean sciences and water quality communities. Scheduled for launch in the 2022 timeframe, PACE is designed to make climate-quality global measurements essential for understanding ocean biology, biogeochemistry and ecology, and determining the role of the ocean in global biogeochemical cycling and ocean ecology, and how it affects and is affected by climate change. PACE will provide high signal-to-noise, hyperspectral observations over an extended spectral range (UV to SWIR) and will have global coverage every 1-2 days, at approximately 1 km spatial resolution; furthermore, PACE is currently designed to include a polarimeter, which will vastly improve atmospheric correction algorithms over water bodies. The PACE mission will enable advances in applications across a range of areas, including oceans, climate, water resources, ecological forecasting, disasters, human health and air quality. HyspIRI, with contiguous measurements in VSWIR, and multispectral measurements in TIR, will be able to provide detailed spectral observations and higher spatial resolution (30 to 60-m) over aquatic systems, but at a temporal resolution that is approximately 5-16 days. HyspIRI would enable improved, detailed studies of aquatic ecosystems, including benthic communities, algal blooms, coral reefs, and wetland species distribution as well as studies of water quality indicators or pollutants such as oil spills, suspended sediment, and colored dissolved organic matter. Together, PACE and HyspIRI will be able to address numerous applications and science priorities, including improving and extending climate data records, and studies of inland, coastal and ocean environments.

Food Quality and Phytoplankton Community Composition in San Francisco Bay using Imaging Spectroscopy Data from the California HyspIRI Airborne Campaign

NASA Astrophysics Data System (ADS)

Palacios, S. L.; Peacock, M. B.; Golini, A. N.; Cloern, J. E.; Senn, D. B.; Guild, L. S.; Kudela, R. M.

2016-12-01

The San Francisco Bay (SFB) is the largest estuary on the west coast of the United States. It is an important transition zone between marine, freshwater, and inland terrestrial watersheds. The SFB is an important region for the cycling of nutrients and pollutants and it supports nurseries of ecologically and commercially important fisheries, including some threatened species. Phytoplankton community structure influences food web dynamics, and the taxonomy of the phytoplankton may be more important in determining primary "food quality" than environmental factors. As such, estimating food quality from phytoplankton community composition can be a robust tool to understand trophic transfer of energy. Recent work explores phytoplankton "food quality" in SFB through the use of microscopy and phytoplankton chemotaxonomy to evaluate how changes in phytoplankton composition may have influenced the recent trophic collapse of pelagic fishes in the northern part of the SFB. The objective of this study is to determine if the approach can also be applied to imaging spectroscopy data in order to quantify phytoplankton "food quality" from space. Imaging spectroscopy data of SFB from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) was collected during the Hyperspectral Infrared (HyspIRI) Airborne Campaign in California (2013 - 2015) and used in this study. Estimates of ocean chlorophyll and phytoplankton community structure were determined using standard ocean chlorophyll algorithms and the PHYtoplankton Detection with Optics (PHYDOTax) algorithms. These were validated using in situ observations of phytoplankton composition using microscopic cell counts and phytoplankton chemotaxonomy from the US Geological Survey's ship surveys of the SFB. The findings from this study may inform the use of future high spectral resolution satellite sensors with the spatial resolution appropriate for coastal systems (e.g., HyspIRI) to assess "food quality" from space.

On techniques for angle compensation in nonideal iris recognition.

PubMed

Schuckers, Stephanie A C; Schmid, Natalia A; Abhyankar, Aditya; Dorairaj, Vivekanand; Boyce, Christopher K; Hornak, Lawrence A

2007-10-01

The popularity of the iris biometric has grown considerably over the past two to three years. Most research has been focused on the development of new iris processing and recognition algorithms for frontal view iris images. However, a few challenging directions in iris research have been identified, including processing of a nonideal iris and iris at a distance. In this paper, we describe two nonideal iris recognition systems and analyze their performance. The word "nonideal" is used in the sense of compensating for off-angle occluded iris images. The system is designed to process nonideal iris images in two steps: 1) compensation for off-angle gaze direction and 2) processing and encoding of the rotated iris image. Two approaches are presented to account for angular variations in the iris images. In the first approach, we use Daugman's integrodifferential operator as an objective function to estimate the gaze direction. After the angle is estimated, the off-angle iris image undergoes geometric transformations involving the estimated angle and is further processed as if it were a frontal view image. The encoding technique developed for a frontal image is based on the application of the global independent component analysis. The second approach uses an angular deformation calibration model. The angular deformations are modeled, and calibration parameters are calculated. The proposed method consists of a closed-form solution, followed by an iterative optimization procedure. The images are projected on the plane closest to the base calibrated plane. Biorthogonal wavelets are used for encoding to perform iris recognition. We use a special dataset of the off-angle iris images to quantify the performance of the designed systems. A series of receiver operating characteristics demonstrate various effects on the performance of the nonideal-iris-based recognition system.

Automatic Classification of Station Quality by Image Based Pattern Recognition of Ppsd Plots

NASA Astrophysics Data System (ADS)

Weber, B.; Herrnkind, S.

2017-12-01

The number of seismic stations is growing and it became common practice to share station waveform data in real-time with the main data centers as IRIS, GEOFON, ORFEUS and RESIF. This made analyzing station performance of increasing importance for automatic real-time processing and station selection. The value of a station depends on different factors as quality and quantity of the data, location of the site and general station density in the surrounding area and finally the type of application it can be used for. The approach described by McNamara and Boaz (2006) became standard in the last decade. It incorporates a probability density function (PDF) to display the distribution of seismic power spectral density (PSD). The low noise model (LNM) and high noise model (HNM) introduced by Peterson (1993) are also displayed in the PPSD plots introduced by McNamara and Boaz allowing an estimation of the station quality. Here we describe how we established an automatic station quality classification module using image based pattern recognition on PPSD plots. The plots were split into 4 bands: short-period characteristics (0.1-0.8 s), body wave characteristics (0.8-5 s), microseismic characteristics (5-12 s) and long-period characteristics (12-100 s). The module sqeval connects to a SeedLink server, checks available stations, requests PPSD plots through the Mustang service from IRIS or PQLX/SQLX or from GIS (gempa Image Server), a module to generate different kind of images as trace plots, map plots, helicorder plots or PPSD plots. It compares the image based quality patterns for the different period bands with the retrieved PPSD plot. The quality of a station is divided into 5 classes for each of the 4 bands. Classes A, B, C, D define regular quality between LNM and HNM while the fifth class represents out of order stations with gain problems, missing data etc. Over all period bands about 100 different patterns are required to classify most of the stations available on the IRIS server. The results are written to a file and stations can be filtered by quality. AAAA represents the best quality in all 4 bands. Also a differentiation between instrument types as broad band and short period stations is possible. A regular check using the IRIS SeedLink and Mustang service allow users to be informed about new stations with a specific quality.

Comparison and evaluation of datasets for off-angle iris recognition

NASA Astrophysics Data System (ADS)

Kurtuncu, Osman M.; Cerme, Gamze N.; Karakaya, Mahmut

2016-05-01

In this paper, we investigated the publicly available iris recognition datasets and their data capture procedures in order to determine if they are suitable for the stand-off iris recognition research. Majority of the iris recognition datasets include only frontal iris images. Even if a few datasets include off-angle iris images, the frontal and off-angle iris images are not captured at the same time. The comparison of the frontal and off-angle iris images shows not only differences in the gaze angle but also change in pupil dilation and accommodation as well. In order to isolate the effect of the gaze angle from other challenging issues including dilation and accommodation, the frontal and off-angle iris images are supposed to be captured at the same time by using two different cameras. Therefore, we developed an iris image acquisition platform by using two cameras in this work where one camera captures frontal iris image and the other one captures iris images from off-angle. Based on the comparison of Hamming distance between frontal and off-angle iris images captured with the two-camera- setup and one-camera-setup, we observed that Hamming distance in two-camera-setup is less than one-camera-setup ranging from 0.05 to 0.001. These results show that in order to have accurate results in the off-angle iris recognition research, two-camera-setup is necessary in order to distinguish the challenging issues from each other.

A novel iris patterns matching algorithm of weighted polar frequency correlation

NASA Astrophysics Data System (ADS)

Zhao, Weijie; Jiang, Linhua

2014-11-01

Iris recognition is recognized as one of the most accurate techniques for biometric authentication. In this paper, we present a novel correlation method - Weighted Polar Frequency Correlation(WPFC) - to match and evaluate two iris images, actually it can also be used for evaluating the similarity of any two images. The WPFC method is a novel matching and evaluating method for iris image matching, which is complete different from the conventional methods. For instance, the classical John Daugman's method of iris recognition uses 2D Gabor wavelets to extract features of iris image into a compact bit stream, and then matching two bit streams with hamming distance. Our new method is based on the correlation in the polar coordinate system in frequency domain with regulated weights. The new method is motivated by the observation that the pattern of iris that contains far more information for recognition is fine structure at high frequency other than the gross shapes of iris images. Therefore, we transform iris images into frequency domain and set different weights to frequencies. Then calculate the correlation of two iris images in frequency domain. We evaluate the iris images by summing the discrete correlation values with regulated weights, comparing the value with preset threshold to tell whether these two iris images are captured from the same person or not. Experiments are carried out on both CASIA database and self-obtained images. The results show that our method is functional and reliable. Our method provides a new prospect for iris recognition system.

Challenging ocular image recognition

NASA Astrophysics Data System (ADS)

Pauca, V. Paúl; Forkin, Michael; Xu, Xiao; Plemmons, Robert; Ross, Arun A.

2011-06-01

Ocular recognition is a new area of biometric investigation targeted at overcoming the limitations of iris recognition performance in the presence of non-ideal data. There are several advantages for increasing the area beyond the iris, yet there are also key issues that must be addressed such as size of the ocular region, factors affecting performance, and appropriate corpora to study these factors in isolation. In this paper, we explore and identify some of these issues with the goal of better defining parameters for ocular recognition. An empirical study is performed where iris recognition methods are contrasted with texture and point operators on existing iris and face datasets. The experimental results show a dramatic recognition performance gain when additional features are considered in the presence of poor quality iris data, offering strong evidence for extending interest beyond the iris. The experiments also highlight the need for the direct collection of additional ocular imagery.

Use of iris recognition camera technology for the quantification of corneal opacification in mucopolysaccharidoses.

PubMed

Aslam, Tariq Mehmood; Shakir, Savana; Wong, James; Au, Leon; Ashworth, Jane

2012-12-01

Mucopolysaccharidoses (MPS) can cause corneal opacification that is currently difficult to objectively quantify. With newer treatments for MPS comes an increased need for a more objective, valid and reliable index of disease severity for clinical and research use. Clinical evaluation by slit lamp is very subjective and techniques based on colour photography are difficult to standardise. In this article the authors present evidence for the utility of dedicated image analysis algorithms applied to images obtained by a highly sophisticated iris recognition camera that is small, manoeuvrable and adapted to achieve rapid, reliable and standardised objective imaging in a wide variety of patients while minimising artefactual interference in image quality.

Iris recognition and what is next? Iris diagnosis: a new challenging topic for machine vision from image acquisition to image interpretation

NASA Astrophysics Data System (ADS)

Perner, Petra

2017-03-01

Molecular image-based techniques are widely used in medicine to detect specific diseases. Look diagnosis is an important issue but also the analysis of the eye plays an important role in order to detect specific diseases. These topics are important topics in medicine and the standardization of these topics by an automatic system can be a new challenging field for machine vision. Compared to iris recognition has the iris diagnosis much more higher demands for the image acquisition and interpretation of the iris. One understands by iris diagnosis (Iridology) the investigation and analysis of the colored part of the eye, the iris, to discover factors, which play an important role for the prevention and treatment of illnesses, but also for the preservation of an optimum health. An automatic system would pave the way for a much wider use of the iris diagnosis for the diagnosis of illnesses and for the purpose of individual health protection. With this paper, we describe our work towards an automatic iris diagnosis system. We describe the image acquisition and the problems with it. Different ways are explained for image acquisition and image preprocessing. We describe the image analysis method for the detection of the iris. The meta-model for image interpretation is given. Based on this model we show the many tasks for image analysis that range from different image-object feature analysis, spatial image analysis to color image analysis. Our first results for the recognition of the iris are given. We describe how detecting the pupil and not wanted lamp spots. We explain how to recognize orange blue spots in the iris and match them against the topological map of the iris. Finally, we give an outlook for further work.

Fuzzy difference-of-Gaussian-based iris recognition method for noisy iris images

NASA Astrophysics Data System (ADS)

Kang, Byung Jun; Park, Kang Ryoung; Yoo, Jang-Hee; Moon, Kiyoung

2010-06-01

Iris recognition is used for information security with a high confidence level because it shows outstanding recognition accuracy by using human iris patterns with high degrees of freedom. However, iris recognition accuracy can be reduced by noisy iris images with optical and motion blurring. We propose a new iris recognition method based on the fuzzy difference-of-Gaussian (DOG) for noisy iris images. This study is novel in three ways compared to previous works: (1) The proposed method extracts iris feature values using the DOG method, which is robust to local variations of illumination and shows fine texture information, including various frequency components. (2) When determining iris binary codes, image noises that cause the quantization error of the feature values are reduced with the fuzzy membership function. (3) The optimal parameters of the DOG filter and the fuzzy membership function are determined in terms of iris recognition accuracy. Experimental results showed that the performance of the proposed method was better than that of previous methods for noisy iris images.

Toward More Accurate Iris Recognition Using Cross-Spectral Matching.

PubMed

Nalla, Pattabhi Ramaiah; Kumar, Ajay

2017-01-01

Iris recognition systems are increasingly deployed for large-scale applications such as national ID programs, which continue to acquire millions of iris images to establish identity among billions. However, with the availability of variety of iris sensors that are deployed for the iris imaging under different illumination/environment, significant performance degradation is expected while matching such iris images acquired under two different domains (either sensor-specific or wavelength-specific). This paper develops a domain adaptation framework to address this problem and introduces a new algorithm using Markov random fields model to significantly improve cross-domain iris recognition. The proposed domain adaptation framework based on the naive Bayes nearest neighbor classification uses a real-valued feature representation, which is capable of learning domain knowledge. Our approach to estimate corresponding visible iris patterns from the synthesis of iris patches in the near infrared iris images achieves outperforming results for the cross-spectral iris recognition. In this paper, a new class of bi-spectral iris recognition system that can simultaneously acquire visible and near infra-red images with pixel-to-pixel correspondences is proposed and evaluated. This paper presents experimental results from three publicly available databases; PolyU cross-spectral iris image database, IIITD CLI and UND database, and achieve outperforming results for the cross-sensor and cross-spectral iris matching.

Computed tomography coronary stent imaging with iterative reconstruction: a trade-off study between medium kernel and sharp kernel.

PubMed

Zhou, Qijing; Jiang, Biao; Dong, Fei; Huang, Peiyu; Liu, Hongtao; Zhang, Minming

2014-01-01

To evaluate the improvement of iterative reconstruction in image space (IRIS) technique in computed tomographic (CT) coronary stent imaging with sharp kernel, and to make a trade-off analysis. Fifty-six patients with 105 stents were examined by 128-slice dual-source CT coronary angiography (CTCA). Images were reconstructed using standard filtered back projection (FBP) and IRIS with both medium kernel and sharp kernel applied. Image noise and the stent diameter were investigated. Image noise was measured both in background vessel and in-stent lumen as objective image evaluation. Image noise score and stent score were performed as subjective image evaluation. The CTCA images reconstructed with IRIS were associated with significant noise reduction compared to that of CTCA images reconstructed using FBP technique in both of background vessel and in-stent lumen (the background noise decreased by approximately 25.4% ± 8.2% in medium kernel (P

Extending the imaging volume for biometric iris recognition.

PubMed

Narayanswamy, Ramkumar; Johnson, Gregory E; Silveira, Paulo E X; Wach, Hans B

2005-02-10

The use of the human iris as a biometric has recently attracted significant interest in the area of security applications. The need to capture an iris without active user cooperation places demands on the optical system. Unlike a traditional optical design, in which a large imaging volume is traded off for diminished imaging resolution and capacity for collecting light, Wavefront Coded imaging is a computational imaging technology capable of expanding the imaging volume while maintaining an accurate and robust iris identification capability. We apply Wavefront Coded imaging to extend the imaging volume of the iris recognition application.

Enhanced iris recognition method based on multi-unit iris images

NASA Astrophysics Data System (ADS)

Shin, Kwang Yong; Kim, Yeong Gon; Park, Kang Ryoung

2013-04-01

For the purpose of biometric person identification, iris recognition uses the unique characteristics of the patterns of the iris; that is, the eye region between the pupil and the sclera. When obtaining an iris image, the iris's image is frequently rotated because of the user's head roll toward the left or right shoulder. As the rotation of the iris image leads to circular shifting of the iris features, the accuracy of iris recognition is degraded. To solve this problem, conventional iris recognition methods use shifting of the iris feature codes to perform the matching. However, this increases the computational complexity and level of false acceptance error. To solve these problems, we propose a novel iris recognition method based on multi-unit iris images. Our method is novel in the following five ways compared with previous methods. First, to detect both eyes, we use Adaboost and a rapid eye detector (RED) based on the iris shape feature and integral imaging. Both eyes are detected using RED in the approximate candidate region that consists of the binocular region, which is determined by the Adaboost detector. Second, we classify the detected eyes into the left and right eyes, because the iris patterns in the left and right eyes in the same person are different, and they are therefore considered as different classes. We can improve the accuracy of iris recognition using this pre-classification of the left and right eyes. Third, by measuring the angle of head roll using the two center positions of the left and right pupils, detected by two circular edge detectors, we obtain the information of the iris rotation angle. Fourth, in order to reduce the error and processing time of iris recognition, adaptive bit-shifting based on the measured iris rotation angle is used in feature matching. Fifth, the recognition accuracy is enhanced by the score fusion of the left and right irises. Experimental results on the iris open database of low-resolution images showed that the averaged equal error rate of iris recognition using the proposed method was 4.3006%, which is lower than that of other methods.

Biometric iris image acquisition system with wavefront coding technology

NASA Astrophysics Data System (ADS)

Hsieh, Sheng-Hsun; Yang, Hsi-Wen; Huang, Shao-Hung; Li, Yung-Hui; Tien, Chung-Hao

2013-09-01

Biometric signatures for identity recognition have been practiced for centuries. Basically, the personal attributes used for a biometric identification system can be classified into two areas: one is based on physiological attributes, such as DNA, facial features, retinal vasculature, fingerprint, hand geometry, iris texture and so on; the other scenario is dependent on the individual behavioral attributes, such as signature, keystroke, voice and gait style. Among these features, iris recognition is one of the most attractive approaches due to its nature of randomness, texture stability over a life time, high entropy density and non-invasive acquisition. While the performance of iris recognition on high quality image is well investigated, not too many studies addressed that how iris recognition performs subject to non-ideal image data, especially when the data is acquired in challenging conditions, such as long working distance, dynamical movement of subjects, uncontrolled illumination conditions and so on. There are three main contributions in this paper. Firstly, the optical system parameters, such as magnification and field of view, was optimally designed through the first-order optics. Secondly, the irradiance constraints was derived by optical conservation theorem. Through the relationship between the subject and the detector, we could estimate the limitation of working distance when the camera lens and CCD sensor were known. The working distance is set to 3m in our system with pupil diameter 86mm and CCD irradiance 0.3mW/cm2. Finally, We employed a hybrid scheme combining eye tracking with pan and tilt system, wavefront coding technology, filter optimization and post signal recognition to implement a robust iris recognition system in dynamic operation. The blurred image was restored to ensure recognition accuracy over 3m working distance with 400mm focal length and aperture F/6.3 optics. The simulation result as well as experiment validates the proposed code apertured imaging system, where the imaging volume was 2.57 times extended over the traditional optics, while keeping sufficient recognition accuracy.

Image Quality Assessment for Fake Biometric Detection: Application to Iris, Fingerprint, and Face Recognition.

PubMed

Galbally, Javier; Marcel, Sébastien; Fierrez, Julian

2014-02-01

To ensure the actual presence of a real legitimate trait in contrast to a fake self-manufactured synthetic or reconstructed sample is a significant problem in biometric authentication, which requires the development of new and efficient protection measures. In this paper, we present a novel software-based fake detection method that can be used in multiple biometric systems to detect different types of fraudulent access attempts. The objective of the proposed system is to enhance the security of biometric recognition frameworks, by adding liveness assessment in a fast, user-friendly, and non-intrusive manner, through the use of image quality assessment. The proposed approach presents a very low degree of complexity, which makes it suitable for real-time applications, using 25 general image quality features extracted from one image (i.e., the same acquired for authentication purposes) to distinguish between legitimate and impostor samples. The experimental results, obtained on publicly available data sets of fingerprint, iris, and 2D face, show that the proposed method is highly competitive compared with other state-of-the-art approaches and that the analysis of the general image quality of real biometric samples reveals highly valuable information that may be very efficiently used to discriminate them from fake traits.

Dynamic Features for Iris Recognition.

PubMed

da Costa, R M; Gonzaga, A

2012-08-01

The human eye is sensitive to visible light. Increasing illumination on the eye causes the pupil of the eye to contract, while decreasing illumination causes the pupil to dilate. Visible light causes specular reflections inside the iris ring. On the other hand, the human retina is less sensitive to near infra-red (NIR) radiation in the wavelength range from 800 nm to 1400 nm, but iris detail can still be imaged with NIR illumination. In order to measure the dynamic movement of the human pupil and iris while keeping the light-induced reflexes from affecting the quality of the digitalized image, this paper describes a device based on the consensual reflex. This biological phenomenon contracts and dilates the two pupils synchronously when illuminating one of the eyes by visible light. In this paper, we propose to capture images of the pupil of one eye using NIR illumination while illuminating the other eye using a visible-light pulse. This new approach extracts iris features called "dynamic features (DFs)." This innovative methodology proposes the extraction of information about the way the human eye reacts to light, and to use such information for biometric recognition purposes. The results demonstrate that these features are discriminating features, and, even using the Euclidean distance measure, an average accuracy of recognition of 99.1% was obtained. The proposed methodology has the potential to be "fraud-proof," because these DFs can only be extracted from living irises.

Use of indocyanine green and sodium fluorescein for anterior segment angiography in ophthalmologically normal cats.

PubMed

Pirie, Chris G; Alario, Anthony

2015-10-01

To assess and compare results of anterior segment angiography of ophthalmologically normal cats following IV injection with indocyanine green and sodium fluorescein dyes. 10 client-owned cats. Anterior segment angiography was performed in anesthetized cats following administration of 0.25% indocyanine green (1.0 mg/kg, IV) or 10% sodium fluorescein (20 mg/kg, IV) solution. All cats received both treatments. Imaging (1 eye/cat) was performed with a full-spectrum digital single-lens reflex camera equipped with an adaptor (1 image/s for 30 seconds) immediately following IV dye injection and 1, 2, 3, 4, and 5 minutes after injection. Onset and duration of arterial, capillary, and venous phases of iris vasculature were identified and compared statistically between treatments. Degree of iridal pigmentation, leakage of dye from iris vasculature, and image quality were subjectively assessed. No differences were found in onset or duration of vascular phases between treatments. Visibility of the iris vasculature was not impaired by poor or moderate iridal pigmentation with either method. Indocyanine green provided subjectively better vascular detail and image contrast than sodium fluorescein. No vascular dye leakage was observed following indocyanine green administration. Leakage of dye from blood vessels in the stroma (in 10 cats) and presence of dye in the anterior chamber (in 5 cats) were detected after sodium fluorescein administration. Images obtained with either fluorescent dye were considered to be of diagnostic quality. Lack of leakage following indocyanine green administration suggested this treatment may have better diagnostic utility for anterior segment angiography. The photographic equipment used provided a cost-effective alternative to existing imaging systems.

Ordinal measures for iris recognition.

PubMed

Sun, Zhenan; Tan, Tieniu

2009-12-01

Images of a human iris contain rich texture information useful for identity authentication. A key and still open issue in iris recognition is how best to represent such textural information using a compact set of features (iris features). In this paper, we propose using ordinal measures for iris feature representation with the objective of characterizing qualitative relationships between iris regions rather than precise measurements of iris image structures. Such a representation may lose some image-specific information, but it achieves a good trade-off between distinctiveness and robustness. We show that ordinal measures are intrinsic features of iris patterns and largely invariant to illumination changes. Moreover, compactness and low computational complexity of ordinal measures enable highly efficient iris recognition. Ordinal measures are a general concept useful for image analysis and many variants can be derived for ordinal feature extraction. In this paper, we develop multilobe differential filters to compute ordinal measures with flexible intralobe and interlobe parameters such as location, scale, orientation, and distance. Experimental results on three public iris image databases demonstrate the effectiveness of the proposed ordinal feature models.

Human iris three-dimensional imaging at micron resolution by a micro-plenoptic camera

PubMed Central

Chen, Hao; Woodward, Maria A.; Burke, David T.; Jeganathan, V. Swetha E.; Demirci, Hakan; Sick, Volker

2017-01-01

A micro-plenoptic system was designed to capture the three-dimensional (3D) topography of the anterior iris surface by simple single-shot imaging. Within a depth-of-field of 2.4 mm, depth resolution of 10 µm can be achieved with accuracy (systematic errors) and precision (random errors) below 20%. We demonstrated the application of our micro-plenoptic imaging system on two healthy irides, an iris with naevi, and an iris with melanoma. The ridges and folds, with height differences of 10~80 µm, on the healthy irides can be effectively captured. The front surface on the iris naevi was flat, and the iris melanoma was 50 ± 10 µm higher than the surrounding iris. The micro-plenoptic imaging system has great potential to be utilized for iris disease diagnosis and continuing, simple monitoring. PMID:29082081

Human iris three-dimensional imaging at micron resolution by a micro-plenoptic camera.

PubMed

Chen, Hao; Woodward, Maria A; Burke, David T; Jeganathan, V Swetha E; Demirci, Hakan; Sick, Volker

2017-10-01

A micro-plenoptic system was designed to capture the three-dimensional (3D) topography of the anterior iris surface by simple single-shot imaging. Within a depth-of-field of 2.4 mm, depth resolution of 10 µm can be achieved with accuracy (systematic errors) and precision (random errors) below 20%. We demonstrated the application of our micro-plenoptic imaging system on two healthy irides, an iris with naevi, and an iris with melanoma. The ridges and folds, with height differences of 10~80 µm, on the healthy irides can be effectively captured. The front surface on the iris naevi was flat, and the iris melanoma was 50 ± 10 µm higher than the surrounding iris. The micro-plenoptic imaging system has great potential to be utilized for iris disease diagnosis and continuing, simple monitoring.

Toward noncooperative iris recognition: a classification approach using multiple signatures.

PubMed

Proença, Hugo; Alexandre, Luís A

2007-04-01

This paper focuses on noncooperative iris recognition, i.e., the capture of iris images at large distances, under less controlled lighting conditions, and without active participation of the subjects. This increases the probability of capturing very heterogeneous images (regarding focus, contrast, or brightness) and with several noise factors (iris obstructions and reflections). Current iris recognition systems are unable to deal with noisy data and substantially increase their error rates, especially the false rejections, in these conditions. We propose an iris classification method that divides the segmented and normalized iris image into six regions, makes an independent feature extraction and comparison for each region, and combines each of the dissimilarity values through a classification rule. Experiments show a substantial decrease, higher than 40 percent, of the false rejection rates in the recognition of noisy iris images.

Optical Coherence Tomography Angiography Characteristics of Iris Melanocytic Tumors

PubMed Central

Skalet, Alison H.; Li, Yan; Lu, Chen D.; Jia, Yali; Lee, ByungKun; Husvogt, Lennart; Maier, Andreas; Fujimoto, James G.; Thomas, Charles R.; Huang, David

2016-01-01

Objective To evaluate tumor vasculature with optical coherence tomography (OCT) angiography (OCTA) in malignant iris melanomas and benign iris lesions. Design Cross-sectional observational clinical study. Participants Patients with iris lesions and healthy volunteers. Methods Eyes were imaged using OCTA systems operating at 1050 and 840 nm wavelengths. Three-dimensional OCTA scans were acquired. Iris melanomas patients treated with radiation therapy were imaged again after I-125 plaque brachytherapy at 6 and 18 months. Main Outcome Measures OCT and OCTA images, qualitative evaluation of iris and tumor vasculature and quantitative vessel density. Results One eye each of eight normal volunteers and nine patients with iris melanomas or benign iris lesions including freckles, nevi, and an iris pigment epithelial (IPE) cyst were imaged. The normal iris has radially-oriented vessels within the stroma on OCTA. Penetration of flow signal in normal iris depended on iris color, with best penetration seen in light to moderately pigmented irides. Iris melanomas demonstrated tortuous and disorganized intratumoral vasculature. In two eyes with nevi there was no increased vascularity; in another, fine vascular loops were noted near an area of ectropion uveae. Iris freckles and the IPE cyst did not have intrinsic vascularity. The vessel density was significantly higher within iris melanomas (34.5%±9.8%, p<0.05) than in benign iris nevi (8.0%±1.4%) or normal irides (8.0%±1.2%). Tumor regression after radiation therapy for melanomas was associated with decreased vessel density. OCTA at 1050 nm provided better visualization of tumor vasculature and penetration through thicker tumors than at 840 nm. But in very thick tumors and highly pigmented lesions even 1050 nm OCTA could not visualize their full thickness. Interpretable OCTA images were obtained in 82% participants in whom imaging was attempted. Conclusions This is the first demonstration of OCTA in iris tumors. OCTA may provide a dye-free, no-injection, cost-effective method for monitoring a variety of tumors including iris melanocytic lesions for growth and vascularity. This could be helpful in evaluating tumors for malignant transformation and response to treatment. Penetration of the OCT beam remains a limitation for highly pigmented tumors, as does the inability to image the entire iris in a single field. PMID:27856029

Optical Coherence Tomography Angiography Characteristics of Iris Melanocytic Tumors.

PubMed

Skalet, Alison H; Li, Yan; Lu, Chen D; Jia, Yali; Lee, ByungKun; Husvogt, Lennart; Maier, Andreas; Fujimoto, James G; Thomas, Charles R; Huang, David

2017-02-01

To evaluate tumor vasculature with optical coherence tomography angiography (OCTA) in malignant iris melanomas and benign iris lesions. Cross-sectional observational clinical study. Patients with iris lesions and healthy volunteers. Eyes were imaged using OCTA systems operating at 1050- and 840-nm wavelengths. Three-dimensional OCTA scans were acquired. Iris melanoma patients treated with radiation therapy were imaged again after I-125 plaque brachytherapy at 6 and 18 months. OCT and OCTA images, qualitative evaluation of iris and tumor vasculature, and quantitative vessel density. One eye each of 8 normal volunteers and 9 patients with iris melanomas or benign iris lesions, including freckles, nevi, and an iris pigment epithelial (IPE) cyst, were imaged. The normal iris has radially oriented vessels within the stroma on OCTA. Penetration of flow signal in normal iris depended on iris color, with best penetration seen in light to moderately pigmented irides. Iris melanomas demonstrated tortuous and disorganized intratumoral vasculature. In 2 eyes with nevi there was no increased vascularity; in another, fine vascular loops were noted near an area of ectropion uveae. Iris freckles and the IPE cyst did not have intrinsic vascularity. The vessel density was significantly higher within iris melanomas (34.5%±9.8%, P < 0.05) than in benign iris nevi (8.0%±1.4%) or normal irides (8.0%±1.2%). Tumor regression after radiation therapy for melanomas was associated with decreased vessel density. OCTA at 1050 nm provided better visualization of tumor vasculature and penetration through thicker tumors than at 840 nm. But in very thick tumors and highly pigmented lesions even 1050-nm OCTA could not visualize their full thickness. Interpretable OCTA images were obtained in 82% of participants in whom imaging was attempted. This is the first demonstration of OCTA in iris tumors. OCTA may provide a dye-free, no-injection, cost-effective method for monitoring a variety of tumors, including iris melanocytic lesions, for growth and vascularity. This could be helpful in evaluating tumors for malignant transformation and response to treatment. Penetration of the OCT beam remains a limitation for highly pigmented tumors, as does the inability to image the entire iris in a single field. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

IRIS family of IRCCD thermal imagers integrating long-life cryogenic coolers, sophisticated algorithms for image enhancement, and hot points detection

NASA Astrophysics Data System (ADS)

Dupuy, Pascal; Harter, Jean

1995-09-01

Iris is a modular infrared thermal image developed by SAGEM since 1988, based on a 288 by 4 IRCCD detector. The first section of the presentation gives a description of the different modules of the IRIS thermal imager and their evolution in recent years. The second section covers the description of the major evolution, namely the integrated detector cooler assembly (IDCA), using a SOFRADIR 288 by 4 detector and a SAGEM microcooler, now integrated in the IRIS thermal imagers. The third section gives the description of two functions integrated in the IRIS thermal imager: (1) image enhancement, using a digital convolution filter, and (2) automatic hot points detection and tracking, offering an assistance to surveillance and automatic detection. The last section presents several programs for navy, air forces, and land applications for which IRIS has already been selected and achieved.

Iris Location Algorithm Based on the CANNY Operator and Gradient Hough Transform

NASA Astrophysics Data System (ADS)

Zhong, L. H.; Meng, K.; Wang, Y.; Dai, Z. Q.; Li, S.

2017-12-01

In the iris recognition system, the accuracy of the localization of the inner and outer edges of the iris directly affects the performance of the recognition system, so iris localization has important research meaning. Our iris data contain eyelid, eyelashes, light spot and other noise, even the gray transformation of the images is not obvious, so the general methods of iris location are unable to realize the iris location. The method of the iris location based on Canny operator and gradient Hough transform is proposed. Firstly, the images are pre-processed; then, calculating the gradient information of images, the inner and outer edges of iris are coarse positioned using Canny operator; finally, according to the gradient Hough transform to realize precise localization of the inner and outer edge of iris. The experimental results show that our algorithm can achieve the localization of the inner and outer edges of the iris well, and the algorithm has strong anti-interference ability, can greatly reduce the location time and has higher accuracy and stability.

Iris recognition via plenoptic imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos-Villalobos, Hector J.; Boehnen, Chris Bensing; Bolme, David S.

Iris recognition can be accomplished for a wide variety of eye images by using plenoptic imaging. Using plenoptic technology, it is possible to correct focus after image acquisition. One example technology reconstructs images having different focus depths and stitches them together, resulting in a fully focused image, even in an off-angle gaze scenario. Another example technology determines three-dimensional data for an eye and incorporates it into an eye model used for iris recognition processing. Another example technology detects contact lenses. Application of the technologies can result in improved iris recognition under a wide variety of scenarios.

80-kVp CT Using Iterative Reconstruction in Image Space Algorithm for the Detection of Hypervascular Hepatocellular Carcinoma: Phantom and Initial Clinical Experience

PubMed Central

Hur, Saebeom; Kim, Soo Jin; Park, Ji Hoon; Han, Joon Koo; Choi, Byung Ihn

2012-01-01

Objective To investigate whether the low-tube-voltage (80-kVp), intermediate-tube-current (340-mAs) MDCT using the Iterative Reconstruction in Image Space (IRIS) algorithm improves lesion-to-liver contrast at reduced radiation dosage while maintaining acceptable image noise in the detection of hepatocellular carcinomas (HCC) in thin (mean body mass index, 24 ± 0.4 kg/m2) adults. Subjects and Methods A phantom simulating the liver with HCC was scanned at 50-400 mAs for 80, 100, 120 and 140-kVp. In addition, fifty patients with HCC who underwent multiphasic liver CT using dual-energy (80-kVp and 140-kVp) arterial scans were enrolled. Virtual 120-kVP scans (protocol A) and 80-kVp scans (protocol B) of the late arterial phase were reconstructed with filtered back-projection (FBP), while corresponding 80-kVp scans were reconstructed with IRIS (protocol C). Contrast-to-noise ratio (CNR) of HCCs and abdominal organs were assessed quantitatively, whereas lesion conspicuity, image noise, and overall image quality were assessed qualitatively. Results IRIS effectively reduced image noise, and yielded 29% higher CNR than the FBP at equivalent tube voltage and current in the phantom study. In the quantitative patient study, protocol C helped improve CNR by 51% and 172% than protocols A and B (p < 0.001), respectively, at equivalent radiation dosage. In the qualitative study, protocol C acquired the highest score for lesion conspicuity albeit with an inferior score to protocol A for overall image quality (p < 0.001). Mean effective dose was 2.63-mSv with protocol A and 1.12-mSv with protocols B and C. Conclusion CT using the low-tube-voltage, intermediate-tube-current and IRIS help improve lesion-to-liver CNR of HCC in thin adults during the arterial phase at a lower radiation dose when compared with the standard technique using 120-kVp and FBP. PMID:22438682

Heterogeneous iris image hallucination using sparse representation on a learned heterogeneous patch dictionary

NASA Astrophysics Data System (ADS)

Li, Yung-Hui; Zheng, Bo-Ren; Ji, Dai-Yan; Tien, Chung-Hao; Liu, Po-Tsun

2014-09-01

Cross sensor iris matching may seriously degrade the recognition performance because of the sensor mis-match problem of iris images between the enrollment and test stage. In this paper, we propose two novel patch-based heterogeneous dictionary learning method to attack this problem. The first method applies the latest sparse representation theory while the second method tries to learn the correspondence relationship through PCA in heterogeneous patch space. Both methods learn the basic atoms in iris textures across different image sensors and build connections between them. After such connections are built, at test stage, it is possible to hallucinate (synthesize) iris images across different sensors. By matching training images with hallucinated images, the recognition rate can be successfully enhanced. The experimental results showed the satisfied results both visually and in terms of recognition rate. Experimenting with an iris database consisting of 3015 images, we show that the EER is decreased 39.4% relatively by the proposed method.

A hyperspectral imaging system for the evaluation of the human iris spectral reflectance

NASA Astrophysics Data System (ADS)

Di Cecilia, Luca; Marazzi, Francesco; Rovati, Luigi

2017-02-01

According to previous studies, the measurement of the human iris pigmentation can be exploited to detect certain eye pathological conditions in their early stage. In this paper, we propose an instrument and a method to perform hyperspectral quantitative measurements of the iris spectral reflectance. The system is based on a simple imaging setup, which includes a monochrome camera mounted on a standard ophthalmic microscope movement controller, a monochromator, and a flashing LED-based slit lamp. To assure quantitative measurements, the system is properly calibrated against a NIST reflectance standard. Iris reflectance images can be obtained in the spectral range 495-795 nm with a resolution of 25 nm. Each image consists of 1280 x 1024 pixels having a spatial resolution of 18 μm. Reflectance spectra can be calculated both from discrete areas of the iris and as the average of the whole iris surface. Preliminary results suggest that hyperspectral imaging of the iris can provide much more morphological and spectral information with respect to conventional qualitative colorimetric methods.

The Hyperspectral Infrared Imager (HyspIRI) Public Health and Air Quality Applications

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Hook, Simon J.

2014-01-01

The neglected tropical diseases (NTDs), a group of chronic, debilitating, and poverty-promoting parasitic, bacterial, and some viral and fungal infections, are among the most common causes of illness of the poorest people living in developing countries. Abiotic environmental factors are important in determining the distribution of disease-causing vectors and their life-cycles. HyspIRI observations can be merged through a Land Data Assimilation System (LDAS) be used to drive spatially-explicit ecological models of NTD vectors distribution and life cycles. Assimilations will be driven by observational data LDAS and satellite-derived meteorological forcing data, parameter datasets, and assimilation observations. HyspIRI hyperspectral measurements would provide global measurements of surface mineralogy and biotic crusts important in accessing the impact of dust in human health. HyspIRI surface thermal measurements would also help identify the variability of dust sources due to surface moisture conditions and map mineralogy.

The Hyperspectral Infrared Imager (HyspIRI) Public Health and Air Quality Applications

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Hook, Simon J.

2013-01-01

The neglected tropical diseases (NTDs), a group of chronic, debilitating, and poverty-promoting parasitic, bacterial, and some viral and fungal infections, are among the most common causes of illness of the poorest people living in developing countries. Abiotic environmental factors are important in determining the distribution of disease-causing vectors and their life-cycles. HyspIRI observations can be merged through a Land Data Assimilation System (LDAS) be used to drive spatially-explicit ecological models of NTD vectors distribution & life cycles. Assimilations will be driven by observational data LDAS and satellite-derived meteorological forcing data, parameter datasets, and assimilation observations. HyspIRI hyperspectral measurements would provide global measurements of surface mineralogy and biotic crusts important in accessing the impact of dust in human health. HyspIRI surface thermal measurements would also help identify the variability of dust sources due to surface moisture conditions and map mineralogy.

The Hyperspectral Infrared Imager (HyspIRI) Public Health & Air Quality Applications

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Hook, Simon J.

2013-01-01

The neglected tropical diseases (NTDs), a group of chronic, debilitating, and poverty-promoting parasitic, bacterial, and some viral and fungal infections, are among the most common causes of illness of the poorest people living in developing countries. Abiotic environmental factors are important in determining the distribution of disease-causing vectors and their life-cycles. HyspIRI observations can be merged through a Land Data Assimilation System (LDAS) be used to drive spatially-explicit ecological models of NTD vectors distribution & life cycles. Assimilations will be driven by observational data LDAS and satellite-derived meteorological forcing data, parameter datasets, and assimilation observations. HyspIRI hyperspectral measurements would provide global measurements of surface mineralogy and biotic crusts important in accessing the impact of dust in human health. HyspIRI surface thermal measurements would also help identify the variability of dust sources due to surface moisture conditions and map mineralogy.

Seismological Data Stewardship at the IRIS DMC: The Role of a Dedicated Data Management System for Seismology

NASA Astrophysics Data System (ADS)

Benson, R. B.; Ahern, T. K.; Trabant, C.; Casey, R.

2011-12-01

Since the founding of the Incorporated Research Institutions for Seismology (IRIS) in 1984, there has been a core program for data management, quite unique at the time, dedicated solely to ensuring that data recorded by IRIS and it's partners had a perpetual data management framework that ensures data will be searchable, well-documented, and preserved so that future generations can, at it's core, have an accurate history of ground motion recordings. This goal is manifest in the IRIS Data Management System, or DMS. The mission of this NSF-EAR facility is "To provide reliable and efficient access to high quality seismological and related geophysical data, generated by IRIS and its domestic and international partners, and to enable all parties interested in using these data to do so in a straightforward and efficient manner". This presentation will focus on the data management business rules that capture the data life-cycle of 3 different segments of seismological and related geophysical data managed by IRIS: - Images and parametric information of historical analog data, - Non-real time quality-controlled digital data, - Real time data that streams into the DMC through a number of different protocols. We will describe how data collection, curation, and distribution to users are cataloged to provide an accurate provenance log of contributed data, which are passed along to both the consumer and network data provider. In addition, we will discuss the need and business rules that apply to metadata and how it is managed.

Multispectral diagnostic imaging of the iris in pigment dispersion syndrome.

PubMed

Roberts, Daniel K; Lukic, Ana; Yang, Yongyi; Wilensky, Jacob T; Wernick, Miles N

2012-08-01

To determine if wavelength selection with near infrared iris imaging may enhance iris transillumination defects (ITDs) in pigment dispersion syndrome. An experimental apparatus was used to acquire iris images in 6 African-American (AA) and 6 White patients with pigment dispersion syndrome. Light-emitting diode probes of 6 different spectral bands (700 to 950 nm) were used to project light into patients' eyes. Iris patterns were photographed, ITD regions of interest were outlined, and region of interest contrasts were calculated for each spectral band. Contrasts varied as a function of wavelength (P<0.0001) for both groups, but tended to be highest in the 700 to 800 nm range. Contrasts were higher in Whites than AAs at 700 nm but the opposite was found at 810 nm (P<0.001). Optimized near infrared iris imaging may be wavelength dependent. Ideal wavelength to image ITDs in more pigmented eyes may be slightly longer than for less pigmented eyes.

Real-time image restoration for iris recognition systems.

PubMed

Kang, Byung Jun; Park, Kang Ryoung

2007-12-01

In the field of biometrics, it has been reported that iris recognition techniques have shown high levels of accuracy because unique patterns of the human iris, which has very many degrees of freedom, are used. However, because conventional iris cameras have small depth-of-field (DOF) areas, input iris images can easily be blurred, which can lead to lower recognition performance, since iris patterns are transformed by the blurring caused by optical defocusing. To overcome these problems, an autofocusing camera can be used. However, this inevitably increases the cost, size, and complexity of the system. Therefore, we propose a new real-time iris image-restoration method, which can increase the camera's DOF without requiring any additional hardware. This paper presents five novelties as compared to previous works: 1) by excluding eyelash and eyelid regions, it is possible to obtain more accurate focus scores from input iris images; 2) the parameter of the point spread function (PSF) can be estimated in terms of camera optics and measured focus scores; therefore, parameter estimation is more accurate than it has been in previous research; 3) because the PSF parameter can be obtained by using a predetermined equation, iris image restoration can be done in real-time; 4) by using a constrained least square (CLS) restoration filter that considers noise, performance can be greatly enhanced; and 5) restoration accuracy can also be enhanced by estimating the weight value of the noise-regularization term of the CLS filter according to the amount of image blurring. Experimental results showed that iris recognition errors when using the proposed restoration method were greatly reduced as compared to those results achieved without restoration or those achieved using previous iris-restoration methods.

Design method of ARM based embedded iris recognition system

NASA Astrophysics Data System (ADS)

Wang, Yuanbo; He, Yuqing; Hou, Yushi; Liu, Ting

2008-03-01

With the advantages of non-invasiveness, uniqueness, stability and low false recognition rate, iris recognition has been successfully applied in many fields. Up to now, most of the iris recognition systems are based on PC. However, a PC is not portable and it needs more power. In this paper, we proposed an embedded iris recognition system based on ARM. Considering the requirements of iris image acquisition and recognition algorithm, we analyzed the design method of the iris image acquisition module, designed the ARM processing module and its peripherals, studied the Linux platform and the recognition algorithm based on this platform, finally actualized the design method of ARM-based iris imaging and recognition system. Experimental results show that the ARM platform we used is fast enough to run the iris recognition algorithm, and the data stream can flow smoothly between the camera and the ARM chip based on the embedded Linux system. It's an effective method of using ARM to actualize portable embedded iris recognition system.

Retinal vascular caliber, iris color, and age-related macular degeneration in the Irish Nun Eye Study.

PubMed

McGowan, Amy; Silvestri, Giuliana; Moore, Evelyn; Silvestri, Vittorio; Patterson, Christopher C; Maxwell, Alexander P; McKay, Gareth J

2014-12-18

To evaluate the relationship between retinal vascular caliber (RVC), iris color, and age-related macular degeneration (AMD) in elderly Irish nuns. Data from 1233 participants in the cross-sectional observational Irish Nun Eye Study were assessed from digital photographs with a standardized protocol using computer-assisted software. Macular images were graded according to the modified Wisconsin Age-related Maculopathy Grading System. Regression models were used to assess associations, adjusting for age, mean arterial blood pressure, body mass index, refraction, and fellow RVC. In total, 1122 (91%) participants had gradable retinal images of sufficient quality for vessel assessment (mean age: 76.3 years [range, 56-100 years]). In an unadjusted analysis, we found some support for a previous finding that individuals with blue iris color had narrower retinal venules compared to those with brown iris color (P < 0.05), but this was no longer significant after adjustment. Age-related macular degeneration status was categorized as no AMD, any AMD, and late AMD only. Individuals with any AMD (early or late AMD) had significantly narrower arterioles and venules compared to those with no AMD in an unadjusted analysis, but this was no longer significant after adjustment. A nonsignificant reduced risk of any AMD or late AMD only was observed in association with brown compared to blue iris color, in both unadjusted and adjusted analyses. Retinal vascular caliber was not significantly associated with iris color or early/late AMD after adjustment for confounders. A lower but nonsignificant AMD risk was observed in those with brown compared to blue iris color. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Iris recognition: on the segmentation of degraded images acquired in the visible wavelength.

PubMed

Proença, Hugo

2010-08-01

Iris recognition imaging constraints are receiving increasing attention. There are several proposals to develop systems that operate in the visible wavelength and in less constrained environments. These imaging conditions engender acquired noisy artifacts that lead to severely degraded images, making iris segmentation a major issue. Having observed that existing iris segmentation methods tend to fail in these challenging conditions, we present a segmentation method that can handle degraded images acquired in less constrained conditions. We offer the following contributions: 1) to consider the sclera the most easily distinguishable part of the eye in degraded images, 2) to propose a new type of feature that measures the proportion of sclera in each direction and is fundamental in segmenting the iris, and 3) to run the entire procedure in deterministically linear time in respect to the size of the image, making the procedure suitable for real-time applications.

An automatic iris occlusion estimation method based on high-dimensional density estimation.

PubMed

Li, Yung-Hui; Savvides, Marios

2013-04-01

Iris masks play an important role in iris recognition. They indicate which part of the iris texture map is useful and which part is occluded or contaminated by noisy image artifacts such as eyelashes, eyelids, eyeglasses frames, and specular reflections. The accuracy of the iris mask is extremely important. The performance of the iris recognition system will decrease dramatically when the iris mask is inaccurate, even when the best recognition algorithm is used. Traditionally, people used the rule-based algorithms to estimate iris masks from iris images. However, the accuracy of the iris masks generated this way is questionable. In this work, we propose to use Figueiredo and Jain's Gaussian Mixture Models (FJ-GMMs) to model the underlying probabilistic distributions of both valid and invalid regions on iris images. We also explored possible features and found that Gabor Filter Bank (GFB) provides the most discriminative information for our goal. Finally, we applied Simulated Annealing (SA) technique to optimize the parameters of GFB in order to achieve the best recognition rate. Experimental results show that the masks generated by the proposed algorithm increase the iris recognition rate on both ICE2 and UBIRIS dataset, verifying the effectiveness and importance of our proposed method for iris occlusion estimation.

Three-dimensional Hessian matrix-based quantitative vascular imaging of rat iris with optical-resolution photoacoustic microscopy in vivo

NASA Astrophysics Data System (ADS)

Zhao, Huangxuan; Wang, Guangsong; Lin, Riqiang; Gong, Xiaojing; Song, Liang; Li, Tan; Wang, Wenjia; Zhang, Kunya; Qian, Xiuqing; Zhang, Haixia; Li, Lin; Liu, Zhicheng; Liu, Chengbo

2018-04-01

For the diagnosis and evaluation of ophthalmic diseases, imaging and quantitative characterization of vasculature in the iris are very important. The recently developed photoacoustic imaging, which is ultrasensitive in imaging endogenous hemoglobin molecules, provides a highly efficient label-free method for imaging blood vasculature in the iris. However, the development of advanced vascular quantification algorithms is still needed to enable accurate characterization of the underlying vasculature. We have developed a vascular information quantification algorithm by adopting a three-dimensional (3-D) Hessian matrix and applied for processing iris vasculature images obtained with a custom-built optical-resolution photoacoustic imaging system (OR-PAM). For the first time, we demonstrate in vivo 3-D vascular structures of a rat iris with a the label-free imaging method and also accurately extract quantitative vascular information, such as vessel diameter, vascular density, and vascular tortuosity. Our results indicate that the developed algorithm is capable of quantifying the vasculature in the 3-D photoacoustic images of the iris in-vivo, thus enhancing the diagnostic capability of the OR-PAM system for vascular-related ophthalmic diseases in vivo.

Iris recognition based on robust principal component analysis

NASA Astrophysics Data System (ADS)

Karn, Pradeep; He, Xiao Hai; Yang, Shuai; Wu, Xiao Hong

2014-11-01

Iris images acquired under different conditions often suffer from blur, occlusion due to eyelids and eyelashes, specular reflection, and other artifacts. Existing iris recognition systems do not perform well on these types of images. To overcome these problems, we propose an iris recognition method based on robust principal component analysis. The proposed method decomposes all training images into a low-rank matrix and a sparse error matrix, where the low-rank matrix is used for feature extraction. The sparsity concentration index approach is then applied to validate the recognition result. Experimental results using CASIA V4 and IIT Delhi V1iris image databases showed that the proposed method achieved competitive performances in both recognition accuracy and computational efficiency.

Iris recognition using image moments and k-means algorithm.

PubMed

Khan, Yaser Daanial; Khan, Sher Afzal; Ahmad, Farooq; Islam, Saeed

2014-01-01

This paper presents a biometric technique for identification of a person using the iris image. The iris is first segmented from the acquired image of an eye using an edge detection algorithm. The disk shaped area of the iris is transformed into a rectangular form. Described moments are extracted from the grayscale image which yields a feature vector containing scale, rotation, and translation invariant moments. Images are clustered using the k-means algorithm and centroids for each cluster are computed. An arbitrary image is assumed to belong to the cluster whose centroid is the nearest to the feature vector in terms of Euclidean distance computed. The described model exhibits an accuracy of 98.5%.

Iris Recognition Using Image Moments and k-Means Algorithm

PubMed Central

Khan, Yaser Daanial; Khan, Sher Afzal; Ahmad, Farooq; Islam, Saeed

2014-01-01

This paper presents a biometric technique for identification of a person using the iris image. The iris is first segmented from the acquired image of an eye using an edge detection algorithm. The disk shaped area of the iris is transformed into a rectangular form. Described moments are extracted from the grayscale image which yields a feature vector containing scale, rotation, and translation invariant moments. Images are clustered using the k-means algorithm and centroids for each cluster are computed. An arbitrary image is assumed to belong to the cluster whose centroid is the nearest to the feature vector in terms of Euclidean distance computed. The described model exhibits an accuracy of 98.5%. PMID:24977221

Improved iris localization by using wide and narrow field of view cameras for iris recognition

NASA Astrophysics Data System (ADS)

Kim, Yeong Gon; Shin, Kwang Yong; Park, Kang Ryoung

2013-10-01

Biometrics is a method of identifying individuals by their physiological or behavioral characteristics. Among other biometric identifiers, iris recognition has been widely used for various applications that require a high level of security. When a conventional iris recognition camera is used, the size and position of the iris region in a captured image vary according to the X, Y positions of a user's eye and the Z distance between a user and the camera. Therefore, the searching area of the iris detection algorithm is increased, which can inevitably decrease both the detection speed and accuracy. To solve these problems, we propose a new method of iris localization that uses wide field of view (WFOV) and narrow field of view (NFOV) cameras. Our study is new as compared to previous studies in the following four ways. First, the device used in our research acquires three images, one each of the face and both irises, using one WFOV and two NFOV cameras simultaneously. The relation between the WFOV and NFOV cameras is determined by simple geometric transformation without complex calibration. Second, the Z distance (between a user's eye and the iris camera) is estimated based on the iris size in the WFOV image and anthropometric data of the size of the human iris. Third, the accuracy of the geometric transformation between the WFOV and NFOV cameras is enhanced by using multiple matrices of the transformation according to the Z distance. Fourth, the searching region for iris localization in the NFOV image is significantly reduced based on the detected iris region in the WFOV image and the matrix of geometric transformation corresponding to the estimated Z distance. Experimental results showed that the performance of the proposed iris localization method is better than that of conventional methods in terms of accuracy and processing time.

A new phase-correlation-based iris matching for degraded images.

PubMed

Krichen, Emine; Garcia-Salicetti, Sonia; Dorizzi, Bernadette

2009-08-01

In this paper, we present a new phase-correlation-based iris matching approach in order to deal with degradations in iris images due to unconstrained acquisition procedures. Our matching system is a fusion of global and local Gabor phase-correlation schemes. The main originality of our local approach is that we do not only consider the correlation peak amplitudes but also their locations in different regions of the images. Results on several degraded databases, namely, the CASIA-BIOSECURE and Iris Challenge Evaluation 2005 databases, show the improvement of our method compared to two available reference systems, Masek and Open Source for Iris (OSRIS), in verification mode.

[Anterior segment tumor imaging: advantages of ultrasound (10, 20 and 50 MHz) and optical coherence tomography].

PubMed

Siahmed, K; Berges, O; Desjardins, L; Lumbroso, L; Brasseur, G

2004-02-01

Detail the role of different imaging techniques for diagnosis of tumors of the iris. Sixty-one tumors of the iris were explored using ultrasound at 10 and 20MHz (Cinescan, BVI Quantel Medical) and 50MHz (UBM, Paradigm) and optical coherence tomography (OCT) (Humphrey Zeiss). Ultrasound should be used at frequencies of 20MHz or greater to precisely characterize, localize and measure a lesion. Ultrasound biomicroscopy (UBM) is inadequate to measure large tumors (extending toward the back of the ciliary body), because of the transducer and the considerably lower image quality caused by the lesion. Ultrasound alone cannot characterize a solid lesion, and moreover cannot differentiate benign and malignant lesions. Clinical notions are also important in diagnosis and patient management. OCT recognizes whether a lesion is liquid or solid in certain cases. With a tumor that seems solid, a 50MHz examination must be done rapidly, and if the entire lesion is difficult to see, a 20MHz ultrasound should be used. With a protruding iris, high-frequency ultrasound and OCT differentiate a cystic lesion from a solid mass, but only BMU provides a precise measurement and regular surveillance capabilities.

The formation of IRIS diagnostics. III. Near-ultraviolet spectra and images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pereira, T. M. D.; Leenaarts, J.; De Pontieu, B.

The Mg II h and k lines are the prime chromospheric diagnostics of NASA's Interface Region Imaging Spectrograph (IRIS). In the previous papers of this series, we used a realistic three-dimensional radiative magnetohydrodynamics model to calculate the h and k lines in detail and investigated how their spectral features relate to the underlying atmosphere. In this work, we employ the same approach to investigate how the h and k diagnostics fare when taking into account the finite resolution of IRIS and different noise levels. In addition, we investigate the diagnostic potential of several other photospheric lines and near-continuum regions presentmore » in the near-ultraviolet (NUV) window of IRIS and study the formation of the NUV slit-jaw images. We find that the instrumental resolution of IRIS has a small effect on the quality of the h and k diagnostics; the relations between the spectral features and atmospheric properties are mostly unchanged. The peak separation is the most affected diagnostic, but mainly due to limitations of the simulation. The effects of noise start to be noticeable at a signal-to-noise ratio (S/N) of 20, but we show that with noise filtering one can obtain reliable diagnostics at least down to a S/N of 5. The many photospheric lines present in the NUV window provide velocity information for at least eight distinct photospheric heights. Using line-free regions in the h and k far wings, we derive good estimates of photospheric temperature for at least three heights. Both of these diagnostics, in particular the latter, can be obtained even at S/Ns as low as 5.« less

Iris recognition based on key image feature extraction.

PubMed

Ren, X; Tian, Q; Zhang, J; Wu, S; Zeng, Y

2008-01-01

In iris recognition, feature extraction can be influenced by factors such as illumination and contrast, and thus the features extracted may be unreliable, which can cause a high rate of false results in iris pattern recognition. In order to obtain stable features, an algorithm was proposed in this paper to extract key features of a pattern from multiple images. The proposed algorithm built an iris feature template by extracting key features and performed iris identity enrolment. Simulation results showed that the selected key features have high recognition accuracy on the CASIA Iris Set, where both contrast and illumination variance exist.

Comments on the CASIA version 1.0 iris data set.

PubMed

Phillips, P Jonathon; Bowyer, Kevin W; Flynn, Patrick J

2007-10-01

We note that the images in the CASIA version 1.0 iris dataset have been edited so that the pupil area is replaced by a circular region of uniform intensity. We recommend that this dataset is no longer used in iris biometrics research, unless there this a compelling reason that takes into account the nature of the images. In addition, based on our experience with the Iris Challenge Evaluation (ICE) 2005 technology development project, we make recommendations for reporting results of iris recognition experiments.

Off-Angle Iris Correction Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos-Villalobos, Hector J; Thompson, Joseph T; Karakaya, Mahmut

In many real world iris recognition systems obtaining consistent frontal images is problematic do to inexperienced or uncooperative users, untrained operators, or distracting environments. As a result many collected images are unusable by modern iris matchers. In this chapter we present four methods for correcting off-angle iris images to appear frontal which makes them compatible with existing iris matchers. The methods include an affine correction, a retraced model of the human eye, measured displacements, and a genetic algorithm optimized correction. The affine correction represents a simple way to create an iris image that appears frontal but it does not accountmore » for refractive distortions of the cornea. The other method account for refraction. The retraced model simulates the optical properties of the cornea. The other two methods are data driven. The first uses optical flow to measure the displacements of the iris texture when compared to frontal images of the same subject. The second uses a genetic algorithm to learn a mapping that optimizes the Hamming Distance scores between off-angle and frontal images. In this paper we hypothesize that the biological model presented in our earlier work does not adequately account for all variations in eye anatomy and therefore the two data-driven approaches should yield better performance. Results are presented using the commercial VeriEye matcher that show that the genetic algorithm method clearly improves over prior work and makes iris recognition possible up to 50 degrees off-angle.« less

A Statistical Analysis of IrisCode and Its Security Implications.

PubMed

Kong, Adams Wai-Kin

2015-03-01

IrisCode has been used to gather iris data for 430 million people. Because of the huge impact of IrisCode, it is vital that it is completely understood. This paper first studies the relationship between bit probabilities and a mean of iris images (The mean of iris images is defined as the average of independent iris images.) and then uses the Chi-square statistic, the correlation coefficient and a resampling algorithm to detect statistical dependence between bits. The results show that the statistical dependence forms a graph with a sparse and structural adjacency matrix. A comparison of this graph with a graph whose edges are defined by the inner product of the Gabor filters that produce IrisCodes shows that partial statistical dependence is induced by the filters and propagates through the graph. Using this statistical information, the security risk associated with two patented template protection schemes that have been deployed in commercial systems for producing application-specific IrisCodes is analyzed. To retain high identification speed, they use the same key to lock all IrisCodes in a database. The belief has been that if the key is not compromised, the IrisCodes are secure. This study shows that even without the key, application-specific IrisCodes can be unlocked and that the key can be obtained through the statistical dependence detected.

The Interface Region Imaging Spectrograph (IRIS) Small Explorer

NASA Astrophysics Data System (ADS)

de Pontieu, B.; Title, A. M.; Schryver, C. J.; Lemen, J. R.; Golub, L.; Kankelborg, C. C.; Carlsson, M.

2009-12-01

The Interface Region Imaging Spectrograph (IRIS) was recently selected as a small explorer mission by NASA. The primary goal of IRIS is to understand how the solar atmosphere is energized. The IRIS investigation combines advanced numerical modeling with a high resolution 20 cm UV imaging spectrograph that will obtain spectra covering temperatures from 4,500 to 10 MK in three wavelength ranges (1332-1358 Angstrom, 1390-1406 Angstrom and 2785-2835 Angstrom) and simultaneous images covering temperatures from 4,500 K to 65,000 K. IRIS will obtain UV spectra and images with high resolution in space (1/3 arcsec) and time (1s) focused on the chromosphere and transition region of the Sun, a complex dynamic interface region between the photosphere and corona. In this region, all but a few percent of the non-radiative energy leaving the Sun is converted into heat and radiation. IRIS fills a crucial gap in our ability to advance Sun-Earth connection studies by tracing the flow of energy and plasma through this foundation of the corona and heliosphere. The IRIS investigation is led by PI Alan Title (LMSAL) with major participation by the Harvard Smithsonian Astrophysical Observatory, Montana State University, NASA Ames Research Center, Stanford University and the University of Oslo (Norway). IRIS is scheduled for launch in late 2012, and will have a nominal two year mission lifetime.

Qualitative Assessment of Ultrasound Biomicroscopic Images Using Standard Photographs: The Liwan Eye Study

PubMed Central

Jiang, Yuzhen; Huang, Wenyong; Huang, Qunxiao; Zhang, Jian; Foster, Paul J.

2010-01-01

Objective. To classify anatomic features related to anterior chamber angles by a qualitative assessment system based on ultrasound biomicroscopy (UBM) images. Methods. Cases of primary angle-closure suspect (PACS), defined by pigmented trabecular meshwork that is not visible in two or more quadrants on static gonioscopy (cases) and systematically selected subjects (1 of every 10) who did not meet this criterion (controls) were enrolled during a population-based survey in Guangzhou, China. All subjects underwent UBM examination. A set of standard UBM images was used to qualitatively classify anatomic features related to the angle configuration, including iris thickness, iris convexity, iris angulation, ciliary body size, and ciliary process position. All analysis was conducted on right eye images. Results. Based on the qualitative grades, the difference in overall iris thickness between gonioscopically narrow eyes (n = 117) and control eyes (n = 57) was not statistically significant. The peripheral one third of the iris tended to be thicker in all quadrants of the PACS eyes, although the difference was statistically significant only in the superior quadrant (P = 0.008). No significant differences were found in the qualitative classifications of iris insertion, iris angulation, ciliary body size, and ciliary process position. The findings were similar when compared with the control group of eyes with wide angles in all quadrants. Conclusions. Basal iris thickness seems to be more relevant to narrow angle configuration than to overall iris thickness. Otherwise, the anterior rotation and size of the ciliary body, the iris insertion, and the overall iris thickness are comparable in narrow- and wide-angle eyes. PMID:19834039

Anterior Segment Optical Coherence Tomography Angiography for Identification of Iris Vasculature and Staging of Iris Neovascularization: A Pilot Study.

PubMed

Roberts, Philipp K; Goldstein, Debra A; Fawzi, Amani A

2017-08-01

Purpose/Aim of the study: To assess the ability of optical coherence tomographic angiography (OCTA) to visualize the normal iris vasculature as well as neovascularization of the iris (NVI). Study participants with healthy eyes, patients at risk of NVI development and patients with active or regressed NVI were consecutively included in this cross-sectional observational study. Imaging was performed using a commercially available OCTA system (RTVue- XR Avanti, Optovue Inc., Fremont, CA, USA). Abnormal iris vessels were graded on OCTA according to a modified clinical staging system and compared to slitlamp and gonioscopic findings. Fifty eyes of 26 study participants (16 healthy eyes, 19 eyes at risk, 15 eyes with different stages of NVI) were imaged using OCTA. In 11 out of 16 healthy eyes (69%) with light or moderately dark iris pigmentation, we observed physiological, radially aligned iris vasculature on OCTA imaging, which could not be visualized in five eyes (31%) with darkly pigmented irides. One eye in the "eyes at risk" group was diagnosed with NVI based on OCTA, which was not observed clinically. Fifteen eyes with clinically active or regressed NVI were imaged. Different stages of NVI could be differentiated by OCTA, corresponding well to an established clinical grading system. Four eyes showed regressed NVI by OCTA, not seen clinically, and were graded as a newly defined stage 4. This pilot clinical study showed that OCTA for imaging of the iris vasculature in health and disease is highly dependent on iris pigmentation. Fine, clinically invisible iris vessels can be visualized by OCTA in the very early stages as well as in the regressed stage of NVI.

Anterior Segment Optical Coherence Tomography Angiography for Identification of Iris Vasculature and Staging of Iris Neovascularization: A Pilot Study

PubMed Central

Roberts, Philipp K.; Goldstein, Debra A.; Fawzi, Amani A.

2017-01-01

Purpose/Aim of the study To assess the ability of optical coherence tomographic angiography (OCTA) to visualize the normal iris vasculature as well as neovascularization of the iris (NVI). Materials and Methods Study participants with healthy eyes, patients at risk of NVI development and patients with active or regressed NVI were consecutively included in this cross-sectional observational study. Imaging was performed using a commercially available OCTA system (RTVue- XR Avanti, Optovue Inc., Fremont, CA, USA). Abnormal iris vessels were graded on OCTA according to a modified clinical staging system and compared to slitlamp and gonioscopic findings. Results Fifty eyes of 26 study participants (16 healthy eyes, 19 eyes at risk, 15 eyes with different stages of NVI) were imaged using OCTA. In 11 out of 16 healthy eyes (69%) with light or moderately dark iris pigmentation, we observed physiological, radially aligned iris vasculature on OCTA imaging, which could not be visualized in five eyes (31%) with darkly pigmented irides. One eye in the “eyes at risk” group was diagnosed with NVI based on OCTA, which was not observed clinically. Fifteen eyes with clinically active or regressed NVI were imaged. Different stages of NVI could be differentiated by OCTA, corresponding well to an established clinical grading system. Four eyes showed regressed NVI by OCTA, not seen clinically, and were graded as a newly defined stage 4. Conclusions This pilot clinical study showed that OCTA for imaging of the iris vasculature in health and disease is highly dependent on iris pigmentation. Fine, clinically invisible iris vessels can be visualized by OCTA in the very early stages as well as in the regressed stage of NVI. PMID:28441067

Development of IR imaging system simulator

NASA Astrophysics Data System (ADS)

Xiang, Xinglang; He, Guojing; Dong, Weike; Dong, Lu

2017-02-01

To overcome the disadvantages of the tradition semi-physical simulation and injection simulation equipment in the performance evaluation of the infrared imaging system (IRIS), a low-cost and reconfigurable IRIS simulator, which can simulate the realistic physical process of infrared imaging, is proposed to test and evaluate the performance of the IRIS. According to the theoretical simulation framework and the theoretical models of the IRIS, the architecture of the IRIS simulator is constructed. The 3D scenes are generated and the infrared atmospheric transmission effects are simulated using OGRE technology in real-time on the computer. The physical effects of the IRIS are classified as the signal response characteristic, modulation transfer characteristic and noise characteristic, and they are simulated on the single-board signal processing platform based on the core processor FPGA in real-time using high-speed parallel computation method.

The infrared imaging spectrograph (IRIS) for TMT: latest science cases and simulations

NASA Astrophysics Data System (ADS)

Wright, Shelley A.; Walth, Gregory; Do, Tuan; Marshall, Daniel; Larkin, James E.; Moore, Anna M.; Adamkovics, Mate; Andersen, David; Armus, Lee; Barth, Aaron; Cote, Patrick; Cooke, Jeff; Chisholm, Eric M.; Davidge, Timothy; Dunn, Jennifer S.; Dumas, Christophe; Ellerbroek, Brent L.; Ghez, Andrea M.; Hao, Lei; Hayano, Yutaka; Liu, Michael; Lopez-Rodriguez, Enrique; Lu, Jessica R.; Mao, Shude; Marois, Christian; Pandey, Shashi B.; Phillips, Andrew C.; Schoeck, Matthias; Subramaniam, Annapurni; Subramanian, Smitha; Suzuki, Ryuji; Tan, Jonathan C.; Terai, Tsuyoshi; Treu, Tommaso; Simard, Luc; Weiss, Jason L.; Wincentsen, James; Wong, Michael; Zhang, Kai

2016-07-01

The Thirty Meter Telescope (TMT) first light instrument IRIS (Infrared Imaging Spectrograph) will complete its preliminary design phase in 2016. The IRIS instrument design includes a near-infrared (0.85 - 2.4 micron) integral field spectrograph (IFS) and imager that are able to conduct simultaneous diffraction-limited observations behind the advanced adaptive optics system NFIRAOS. The IRIS science cases have continued to be developed and new science studies have been investigated to aid in technical performance and design requirements. In this development phase, the IRIS science team has paid particular attention to the selection of filters, gratings, sensitivities of the entire system, and science cases that will benefit from the parallel mode of the IFS and imaging camera. We present new science cases for IRIS using the latest end-to-end data simulator on the following topics: Solar System bodies, the Galactic center, active galactic nuclei (AGN), and distant gravitationally-lensed galaxies. We then briefly discuss the necessity of an advanced data management system and data reduction pipeline.

Design and performance evaluation of a high resolution IRI-microPET preclinical scanner

NASA Astrophysics Data System (ADS)

Islami rad, S. Z.; Peyvandi, R. Gholipour; lehdarboni, M. Askari; Ghafari, A. A.

2015-05-01

PET for small animal, IRI-microPET, was designed and built at the NSTRI. The scanner is made of four detectors positioned on a rotating gantry at a distance 50 mm from the center. Each detector consists of a 10×10 crystal matrix of 2×2×10 mm3 directly coupled to a PS-PMT. A position encoding circuit for specific PS-PMT has been designed, built and tested with a PD-MFS-2MS/s-8/14 data acquisition board. After implementing reconstruction algorithms (FBP, MLEM and SART) on sinograms, images quality and system performance were evaluated by energy resolution, timing resolution, spatial resolution, scatter fraction, sensitivity, RMS contrast and SNR parameters. The energy spectra were obtained for the crystals with an energy window of 300-700 keV. The energy resolution in 511 keV averaged over all modules, detectors, and crystals, was 23.5%. A timing resolution of 2.4 ns FWHM obtained by coincidence timing spectrum was measured with crystal LYSO. The radial and tangential resolutions for 18F (1.15-mm inner diameter) at the center of the field of view were 1.81 mm and 1.90 mm, respectively. At a radial offset of 5 mm, the FWHM values were 1.96 and 2.06 mm. The system scatter fraction was 7.1% for the mouse phantom. The sensitivity was measured for different energy windows, leading to a sensitivity of 1.74% at the center of FOV. Also, images quality was evaluated by RMS contrast and SNR factors, and the results show that the reconstructed images by MLEM algorithm have the best RMS contrast, and SNR. The IRI-microPET presents high image resolution, low scatter fraction values and improved SNR for animal studies.

Iridoschisis: high frequency ultrasound imaging. Evidence for a genetic defect?

PubMed Central

Danias, J; Aslanides, I M; Eichenbaum, J W; Silverman, R H; Reinstein, D Z; Coleman, D J

1996-01-01

AIMS: To elucidate changes in the anatomy of the anterior chamber associated with iridoschisis, a rare form of iris atrophy, and their potential contribution to angle closure glaucoma. METHODS: Both eyes of a 71-year-old woman with bilateral iridoschisis and fibrous dysplasia and her asymptomatic 50-year-old daughter were scanned with a very high frequency (50 MHz) ultrasound system. RESULTS: The symptomatic patient exhibited diffuse changes in the iris stoma with an intact posterior iris pigmented layer in both eyes. These changes were clinically compatible with the lack of iris transillumination defects. Additionally, iris bowing with a resultant narrowing of the angle occurred. The asymptomatic daughter showed discrete, but less severe iris stromal changes. CONCLUSION: This is the first detailed study of high frequency ultrasonic imaging of the iris in iridoschisis. The observed structural changes suggest angle narrowing by forward bowing of the anterior iris stroma may be a mechanism of IOP elevation in this condition. The ultrasonic detection of iris changes in the asymptomatic daughter of the symptomatic patient and the association of iridoschisis with fibrous dysplasia suggest a possible genetic component in the pathogenesis of this condition. Images PMID:9059271

The infrared imaging spectrograph (IRIS) for TMT: overview of innovative science programs

NASA Astrophysics Data System (ADS)

Wright, Shelley A.; Larkin, James E.; Moore, Anna M.; Do, Tuan; Simard, Luc; Adamkovics, Maté; Armus, Lee; Barth, Aaron J.; Barton, Elizabeth; Boyce, Hope; Cooke, Jeffrey; Cote, Patrick; Davidge, Timothy; Ellerbroek, Brent; Ghez, Andrea M.; Liu, Michael C.; Lu, Jessica R.; Macintosh, Bruce A.; Mao, Shude; Marois, Christian; Schoeck, Matthias; Suzuki, Ryuji; Tan, Jonathan C.; Treu, Tommaso; Wang, Lianqi; Weiss, Jason

2014-07-01

IRIS (InfraRed Imaging Spectrograph) is a first light near-infrared diffraction limited imager and integral field spectrograph being designed for the future Thirty Meter Telescope (TMT). IRIS is optimized to perform astronomical studies across a significant fraction of cosmic time, from our Solar System to distant newly formed galaxies (Barton et al. [1]). We present a selection of the innovative science cases that are unique to IRIS in the era of upcoming space and ground-based telescopes. We focus on integral field spectroscopy of directly imaged exoplanet atmospheres, probing fundamental physics in the Galactic Center, measuring 104 to 1010 M supermassive black hole masses, resolved spectroscopy of young star-forming galaxies (1 < z < 5) and first light galaxies (6 < z < 12), and resolved spectroscopy of strong gravitational lensed sources to measure dark matter substructure. For each of these science cases we use the IRIS simulator (Wright et al. [2], Do et al. [3]) to explore IRIS capabilities. To highlight the unique IRIS capabilities, we also update the point and resolved source sensitivities for the integral field spectrograph (IFS) in all five broadband filters (Z, Y, J, H, K) for the finest spatial scale of 0.004" per spaxel. We briefly discuss future development plans for the data reduction pipeline and quicklook software for the IRIS instrument suite.

Towards online iris and periocular recognition under relaxed imaging constraints.

PubMed

Tan, Chun-Wei; Kumar, Ajay

2013-10-01

Online iris recognition using distantly acquired images in a less imaging constrained environment requires the development of a efficient iris segmentation approach and recognition strategy that can exploit multiple features available for the potential identification. This paper presents an effective solution toward addressing such a problem. The developed iris segmentation approach exploits a random walker algorithm to efficiently estimate coarsely segmented iris images. These coarsely segmented iris images are postprocessed using a sequence of operations that can effectively improve the segmentation accuracy. The robustness of the proposed iris segmentation approach is ascertained by providing comparison with other state-of-the-art algorithms using publicly available UBIRIS.v2, FRGC, and CASIA.v4-distance databases. Our experimental results achieve improvement of 9.5%, 4.3%, and 25.7% in the average segmentation accuracy, respectively, for the UBIRIS.v2, FRGC, and CASIA.v4-distance databases, as compared with most competing approaches. We also exploit the simultaneously extracted periocular features to achieve significant performance improvement. The joint segmentation and combination strategy suggest promising results and achieve average improvement of 132.3%, 7.45%, and 17.5% in the recognition performance, respectively, from the UBIRIS.v2, FRGC, and CASIA.v4-distance databases, as compared with the related competing approaches.

Characterization of iris pattern stretches and application to the measurement of roll axis eye movements.

PubMed

Nishiyama, Junpei; Hashimoto, Tsutomu; Sakashita, Yusuke; Fujiyoshi, Hironobu; Hirata, Yutaka

2008-01-01

Eye movements are utilized in many scientific studies as a probe that reflects the neural representation of 3 dimensional extrapersonal space. This study proposes a method to accurately measure the roll component of eye movements under the conditions in which the pupil diameter changes. Generally, the iris pattern matching between a reference and a test iris image is performed to estimate roll angle of the test image. However, iris patterns are subject to change when the pupil size changes, thus resulting in less accurate roll angle estimation if the pupil sizes in the test and reference images are different. We characterized non-uniform iris pattern contraction/expansion caused by pupil dilation/constriction, and developed an algorithm to convert an iris pattern with an arbitrary pupil size into that with the same pupil size as the reference iris pattern. It was demonstrated that the proposed method improved the accuracy of the measurement of roll eye movement by up to 76.9%.

Multi-image encryption based on synchronization of chaotic lasers and iris authentication

NASA Astrophysics Data System (ADS)

Banerjee, Santo; Mukhopadhyay, Sumona; Rondoni, Lamberto

2012-07-01

A new technique of transmitting encrypted combinations of gray scaled and chromatic images using chaotic lasers derived from Maxwell-Bloch's equations has been proposed. This novel scheme utilizes the general method of solution of a set of linear equations to transmit similar sized heterogeneous images which are a combination of monochrome and chromatic images. The chaos encrypted gray scaled images are concatenated along the three color planes resulting in color images. These are then transmitted over a secure channel along with a cover image which is an iris scan. The entire cryptology is augmented with an iris-based authentication scheme. The secret messages are retrieved once the authentication is successful. The objective of our work is briefly outlined as (a) the biometric information is the iris which is encrypted before transmission, (b) the iris is used for personal identification and verifying for message integrity, (c) the information is transmitted securely which are colored images resulting from a combination of gray images, (d) each of the images transmitted are encrypted through chaos based cryptography, (e) these encrypted multiple images are then coupled with the iris through linear combination of images before being communicated over the network. The several layers of encryption together with the ergodicity and randomness of chaos render enough confusion and diffusion properties which guarantee a fool-proof approach in achieving secure communication as demonstrated by exhaustive statistical methods. The result is vital from the perspective of opening a fundamental new dimension in multiplexing and simultaneous transmission of several monochromatic and chromatic images along with biometry based authentication and cryptography.

Land Cover Classification of the Jornada Experimental Range with Simulated HyspIRI Data

NASA Astrophysics Data System (ADS)

Thorp, K. R.; French, A. N.

2011-12-01

The proposed NASA mission, HyspIRI, would facilitate the use of hyperspectral satellite remote sensing images for monitoring a variety of Earth system processes. We utilized four years of AVIRIS data of the USDA Jornada Experimental Range in southern New Mexico to simulate the visible and near-infrared bands of the planned HyspIRI satellite. Vegetation dynamics at Jornada has been the subject of several recent studies due to concerns of invasive plant species encroaching on native rangeland grasses. Our objective was to assess the added value of simulated HyspIRI images to appropriately classify rangeland vegetation. The AVIRIS images were georeferenced to an orthophoto of the region and 's6' was implemented for atmospheric correction. Images were resampled to simulate HyspIRI wavebands in the visible and near-infrared. Supervised image classification based on observed spectra of rangeland vegetation species was used to map spatial vegetation cover class and temporal dynamics over four years. Forthcoming results will identify the added value of hyperspectral images, as compared to broadband images, for monitoring vegetation dynamics at Jornada.

NOVEL OBSERVATIONS AND POTENTIAL APPLICATIONS USING DIGITAL INFRARED IRIS IMAGING

PubMed Central

Roberts, Daniel K.; Lukic, Ana; Yang, Yongyi; Moroi, Sayoko E.; Wilensky, Jacob T.; Wernick, Miles N.

2017-01-01

Digital infrared (IR) iris photography using a modified digital camera system was carried out on about 300 subjects seen during routine clinical care and research at one facility. Since this image database offered opportunity to gain new insight into the potential utility of IR iris imaging, it was surveyed for unique image patterns. Then, a selection of photos was compiled that would illustrate the spectrum of this imaging experience. Potentially informative image patterns were observed in subjects with cataracts, diabetic retinopathy, Posner-Schlossman syndrome, iridociliary cysts, long anterior lens zonules, nevi, oculocutaneous albinism, pigment dispersion syndrome, pseudophakia, suspected vascular anomaly, and trauma. Image patterns were often unanticipated regardless of pre-existing information and suggest that IR iris imaging may have numerous potential clinical and research applications, some of which may still not be recognized. These observations suggest further development and study of this technology. PMID:19320317

Method of preliminary localization of the iris in biometric access control systems

NASA Astrophysics Data System (ADS)

Minacova, N.; Petrov, I.

2015-10-01

This paper presents a method of preliminary localization of the iris, based on the stable brightness features of the iris in images of the eye. In tests on images of eyes from publicly available databases method showed good accuracy and speed compared to existing methods preliminary localization.

Wavefront sensorless adaptive optics optical coherence tomography for in vivo retinal imaging in mice

PubMed Central

Jian, Yifan; Xu, Jing; Gradowski, Martin A.; Bonora, Stefano; Zawadzki, Robert J.; Sarunic, Marinko V.

2014-01-01

We present wavefront sensorless adaptive optics (WSAO) Fourier domain optical coherence tomography (FD-OCT) for in vivo small animal retinal imaging. WSAO is attractive especially for mouse retinal imaging because it simplifies optical design and eliminates the need for wavefront sensing, which is difficult in the small animal eye. GPU accelerated processing of the OCT data permitted real-time extraction of image quality metrics (intensity) for arbitrarily selected retinal layers to be optimized. Modal control of a commercially available segmented deformable mirror (IrisAO Inc.) provided rapid convergence using a sequential search algorithm. Image quality improvements with WSAO OCT are presented for both pigmented and albino mouse retinal data, acquired in vivo. PMID:24575347

Iris Segmentation and Normalization Algorithm Based on Zigzag Collarette

NASA Astrophysics Data System (ADS)

Rizky Faundra, M.; Ratna Sulistyaningrum, Dwi

2017-01-01

In this paper, we proposed iris segmentation and normalization algorithm based on the zigzag collarette. First of all, iris images are processed by using Canny Edge Detection to detect pupil edge, then finding the center and the radius of the pupil with the Hough Transform Circle. Next, isolate important part in iris based zigzag collarette area. Finally, Daugman Rubber Sheet Model applied to get the fixed dimensions or normalization iris by transforming cartesian into polar format and thresholding technique to remove eyelid and eyelash. This experiment will be conducted with a grayscale eye image data taken from a database of iris-Chinese Academy of Sciences Institute of Automation (CASIA). Data iris taken is the data reliable and widely used to study the iris biometrics. The result show that specific threshold level is 0.3 have better accuracy than other, so the present algorithm can be used to segmentation and normalization zigzag collarette with accuracy is 98.88%

[Electronic Device for Retinal and Iris Imaging].

PubMed

Drahanský, M; Kolář, R; Mňuk, T

This paper describes design and construction of a new device for automatic capturing of eye retina and iris. This device has two possible ways of utilization - either for biometric purposes (persons recognition on the base of their eye characteristics) or for medical purposes as supporting diagnostic device. eye retina, eye iris, device, acquisition, image.

Efficient iris recognition by characterizing key local variations.

PubMed

Ma, Li; Tan, Tieniu; Wang, Yunhong; Zhang, Dexin

2004-06-01

Unlike other biometrics such as fingerprints and face, the distinct aspect of iris comes from randomly distributed features. This leads to its high reliability for personal identification, and at the same time, the difficulty in effectively representing such details in an image. This paper describes an efficient algorithm for iris recognition by characterizing key local variations. The basic idea is that local sharp variation points, denoting the appearing or vanishing of an important image structure, are utilized to represent the characteristics of the iris. The whole procedure of feature extraction includes two steps: 1) a set of one-dimensional intensity signals is constructed to effectively characterize the most important information of the original two-dimensional image; 2) using a particular class of wavelets, a position sequence of local sharp variation points in such signals is recorded as features. We also present a fast matching scheme based on exclusive OR operation to compute the similarity between a pair of position sequences. Experimental results on 2255 iris images show that the performance of the proposed method is encouraging and comparable to the best iris recognition algorithm found in the current literature.

Biometric image enhancement using decision rule based image fusion techniques

NASA Astrophysics Data System (ADS)

Sagayee, G. Mary Amirtha; Arumugam, S.

2010-02-01

Introducing biometrics into information systems may result in considerable benefits. Most of the researchers confirmed that the finger print is widely used than the iris or face and more over it is the primary choice for most privacy concerned applications. For finger prints applications, choosing proper sensor is at risk. The proposed work deals about, how the image quality can be improved by introducing image fusion technique at sensor levels. The results of the images after introducing the decision rule based image fusion technique are evaluated and analyzed with its entropy levels and root mean square error.

Evaluation and application of new AVIRIS data for the study of coral reefs in Hawaiian Islands

NASA Astrophysics Data System (ADS)

Wei, J.; Lee, Z.

2017-12-01

During the HyspIRI Hawaii campaign in early 2017, we collected hyperspectral remote sensing reflectance over coral reef environments in Kaneohe Bay in Oahu and the coastal waters of Maui Island. Based on in-situ measurements, we evaluated the data quality of reflectance measurements by the Airborne Visible-Infrared Imaging Spectrometer (AVIRIS). Further, these data were used to refine the remote sensing algorithms for identification of live corals, water bathymetry, and water clarity for the entire flight lines. Our results suggested great improvement in our understanding and capabilities of using HyspIRI-like data to observe and monitor coral reef environments.

Iris autofluorescence in Fuchs' heterochromic uveitis.

PubMed

Liu, Qian; Jia, Yading; Zhang, Suhua; Xie, Juan; Chang, Xin; Hou, Jia; Li, Gaiyun; Koch, Douglas D; Wang, Li

2016-10-01

To explore the characteristic autofluorescence patterns of iris depigmentation in eyes diagnosed with Fuchs' heterochromic uveitis (FHU). Near-infrared autofluorescence images and colour images of iris were taken in 21 eyes of 21 patients with FHU, 30 eyes of 15 normal subjects, 30 eyes of 15 normal age-related iris atrophy and 33 eyes of 20 patients with uveitis other than FHU. The confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph 2, HRA2) was used for melanin-related autofluorescence imaging. The indocyanine green angiography mode of HRA2 was applied for near-infrared laser imaging, and the wavelength of the excitation laser was 795 nm. Iris colour images were also taken with the slit lamp. In normal iris, moderately intense autofluorescence was noted for the pigment ruff at the pupillary border, the crests in the pupillary zone and the collarette; and there was mild autofluorescence in the ciliary zone. In eyes with age-related iris atrophy and uveitis, much less autofluorescence was seen than the healthy normal irides. In eyes with FHU, there was moderate but discontinuous autofluorescence in the pigment ruff, a petaloid pattern of autofluorescence in the pupillary zone, moderate autofluorescence in the collarette and reticular pattern of autofluorescence in the ciliary zone. Characteristic autofluorescence patterns appeared in eyes diagnosed with FHU. Near-infrared autofluorescence is a promising objective technique to document the iris changes in FHU. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Unified framework for automated iris segmentation using distantly acquired face images.

PubMed

Tan, Chun-Wei; Kumar, Ajay

2012-09-01

Remote human identification using iris biometrics has high civilian and surveillance applications and its success requires the development of robust segmentation algorithm to automatically extract the iris region. This paper presents a new iris segmentation framework which can robustly segment the iris images acquired using near infrared or visible illumination. The proposed approach exploits multiple higher order local pixel dependencies to robustly classify the eye region pixels into iris or noniris regions. Face and eye detection modules have been incorporated in the unified framework to automatically provide the localized eye region from facial image for iris segmentation. We develop robust postprocessing operations algorithm to effectively mitigate the noisy pixels caused by the misclassification. Experimental results presented in this paper suggest significant improvement in the average segmentation errors over the previously proposed approaches, i.e., 47.5%, 34.1%, and 32.6% on UBIRIS.v2, FRGC, and CASIA.v4 at-a-distance databases, respectively. The usefulness of the proposed approach is also ascertained from recognition experiments on three different publicly available databases.

On-instrument wavefront sensor design for the TMT infrared imaging spectrograph (IRIS) update

NASA Astrophysics Data System (ADS)

Dunn, Jennifer; Reshetov, Vladimir; Atwood, Jenny; Pazder, John; Wooff, Bob; Loop, David; Saddlemyer, Leslie; Moore, Anna M.; Larkin, James E.

2014-08-01

The first light instrument on the Thirty Meter Telescope (TMT) project will be the InfraRed Imaging Spectrograph (IRIS). IRIS will be mounted on a bottom port of the facility AO instrument NFIRAOS. IRIS will report guiding information to the NFIRAOS through the On-Instrument Wavefront Sensor (OIWFS) that is part of IRIS. This will be in a self-contained compartment of IRIS and will provide three deployable wavefront sensor probe arms. This entire unit will be rotated to provide field de-rotation. Currently in our preliminary design stage our efforts have included: prototyping of the probe arm to determine the accuracy of this critical component, handling cart design and reviewing different types of glass for the atmospheric dispersion.

Point spread function engineering for iris recognition system design.

PubMed

Ashok, Amit; Neifeld, Mark A

2010-04-01

Undersampling in the detector array degrades the performance of iris-recognition imaging systems. We find that an undersampling of 8 x 8 reduces the iris-recognition performance by nearly a factor of 4 (on CASIA iris database), as measured by the false rejection ratio (FRR) metric. We employ optical point spread function (PSF) engineering via a Zernike phase mask in conjunction with multiple subpixel shifted image measurements (frames) to mitigate the effect of undersampling. A task-specific optimization framework is used to engineer the optical PSF and optimize the postprocessing parameters to minimize the FRR. The optimized Zernike phase enhanced lens (ZPEL) imager design with one frame yields an improvement of nearly 33% relative to a thin observation module by bounded optics (TOMBO) imager with one frame. With four frames the optimized ZPEL imager achieves a FRR equal to that of the conventional imager without undersampling. Further, the ZPEL imager design using 16 frames yields a FRR that is actually 15% lower than that obtained with the conventional imager without undersampling.

On a methodology for robust segmentation of nonideal iris images.

PubMed

Schmid, Natalia A; Zuo, Jinyu

2010-06-01

Iris biometric is one of the most reliable biometrics with respect to performance. However, this reliability is a function of the ideality of the data. One of the most important steps in processing nonideal data is reliable and precise segmentation of the iris pattern from remaining background. In this paper, a segmentation methodology that aims at compensating various nonidealities contained in iris images during segmentation is proposed. The virtue of this methodology lies in its capability to reliably segment nonideal imagery that is simultaneously affected with such factors as specular reflection, blur, lighting variation, occlusion, and off-angle images. We demonstrate the robustness of our segmentation methodology by evaluating ideal and nonideal data sets, namely, the Chinese Academy of Sciences iris data version 3 interval subdirectory, the iris challenge evaluation data, the West Virginia University (WVU) data, and the WVU off-angle data. Furthermore, we compare our performance to that of our implementation of Camus and Wildes's algorithm and Masek's algorithm. We demonstrate considerable improvement in segmentation performance over the formerly mentioned algorithms.

Hi-C Observations of Penumbral Bright Dots

NASA Technical Reports Server (NTRS)

Alpert, S. E.; Tiwari, S. K.; Moore, R. L.; Savage, S. L.; Winebarger, A. R.

2014-01-01

We use high-quality data obtained by the High Resolution Coronal Imager (Hi-C) to examine bright dots (BDs) in a sunspot's penumbra. The sizes of these BDs are on the order of 1 arcsecond (1") and are therefore hard to identify using the Atmospheric Imaging Assembly's (AIA) 0.6" pixel(exp -1) resolution. These BD become readily apparent with Hi-C's 0.1" pixel(exp -1) resolution. Tian et al. (2014) found penumbral BDs in the transition region (TR) by using the Interface Region Imaging Spectrograph (IRIS). However, only a few of their dots could be associated with any enhanced brightness in AIA channels. In this work, we examine the characteristics of the penumbral BDs observed by Hi-C in a sunspot penumbra, including their sizes, lifetimes, speeds, and intensity. We also attempt to find any association of these BDs to the IRIS BDs. There are fewer Hi-C BDs in the penumbra than seen by IRIS, though different sunspots were studied. We use 193 Angstroms Hi-C data from July 11, 2012 which observed from approximately 18:52:00 UT- 18:56:00 UT and supplement it with data from AIA's 193 Angstrom passband to see the complete lifetime of the dots that were born before and/or lasted longer than Hi- C's 5-minute observation period. We use additional AIA passbands and compare the light curves of the BDs at different temperatures to test whether the Hi-C BDs are TR BDs. We find that most Hi-C BDs show clear movement, and of those that do, they move in a radial direction, toward or away from the sunspot umbra. Single BDs interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to move less. Many of the properties of our BDs are similar to the extreme values of the IRIS BDs, e.g., they move slower on average and their sizes and lifetimes are on the higher end of the IRIS BDs. We infer that our penumbral BDs are the large-scale end of the distribution of BDs observed by IRIS.

Hi-C Observations of Penumbral Bright Dots

NASA Astrophysics Data System (ADS)

Alpert, S.; Tiwari, S. K.; Moore, R. L.; Savage, S. L.; Winebarger, A. R.

2014-12-01

We use high-quality data obtained by the High Resolution Coronal Imager (Hi-C) to examine bright dots (BDs) in a sunspot's penumbra. The sizes of these BDs are on the order of 1 arcsecond (1") and are therefore hard to identify using the Atmospheric Imaging Assembly's (AIA) 0.6" pixel-1 resolution. These BDs become readily apparent with Hi-C's 0.1" pixel-1 resolution. Tian et al. (2014) found penumbral BDs in the transition region (TR) by using the Interface Region Imaging Spectrograph (IRIS). However, only a few of their dots could be associated with any enhanced brightness in AIA channels. In this work, we examine the characteristics of the penumbral BDs observed by Hi-C in a sunspot penumbra, including their sizes, lifetimes, speeds, and intensity. We also attempt to relate these BDs to the IRIS BDs. There are fewer Hi-C BDs in the penumbra than seen by IRIS, though different sunspots were studied. We use 193Å Hi-C data from July 11, 2012 which observed from ~18:52:00 UT--18:56:00 UT and supplement it with data from AIA's 193Å passband to see the complete lifetime of the dots that were born before and/or lasted longer than Hi-C's 5-minute observation period. We use additional AIA passbands and compare the light curves of the BDs at different temperatures to test whether the Hi-C BDs are TR BDs. We find that most Hi-C BDs show clear movement, and of those that do, they move in a radial direction, toward or away from the sunspot umbra. Single BDs interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to move less. Our BDs are similar to the exceptional IRIS BDs: they move slower on average and their sizes and lifetimes are on the high end of the distribution of IRIS BDs. We infer that our penumbral BDs are some of the larger BDs observed by IRIS, those that are bright enough in TR emission to be seen in the 193Å band of Hi-C.

Hyperspectral optical imaging of human iris in vivo: characteristics of reflectance spectra

NASA Astrophysics Data System (ADS)

Medina, José M.; Pereira, Luís M.; Correia, Hélder T.; Nascimento, Sérgio M. C.

2011-07-01

We report a hyperspectral imaging system to measure the reflectance spectra of real human irises with high spatial resolution. A set of ocular prosthesis was used as the control condition. Reflectance data were decorrelated by the principal-component analysis. The main conclusion is that spectral complexity of the human iris is considerable: between 9 and 11 principal components are necessary to account for 99% of the cumulative variance in human irises. Correcting image misalignments associated with spontaneous ocular movements did not influence this result. The data also suggests a correlation between the first principal component and different levels of melanin present in the irises. It was also found that although the spectral characteristics of the first five principal components were not affected by the radial and angular position of the selected iridal areas, they affect the higher-order ones, suggesting a possible influence of the iris texture. The results show that hyperspectral imaging in the iris, together with adequate spectroscopic analyses provide more information than conventional colorimetric methods, making hyperspectral imaging suitable for the characterization of melanin and the noninvasive diagnosis of ocular diseases and iris color.

Optimal wavelength band clustering for multispectral iris recognition.

PubMed

Gong, Yazhuo; Zhang, David; Shi, Pengfei; Yan, Jingqi

2012-07-01

This work explores the possibility of clustering spectral wavelengths based on the maximum dissimilarity of iris textures. The eventual goal is to determine how many bands of spectral wavelengths will be enough for iris multispectral fusion and to find these bands that will provide higher performance of iris multispectral recognition. A multispectral acquisition system was first designed for imaging the iris at narrow spectral bands in the range of 420 to 940 nm. Next, a set of 60 human iris images that correspond to the right and left eyes of 30 different subjects were acquired for an analysis. Finally, we determined that 3 clusters were enough to represent the 10 feature bands of spectral wavelengths using the agglomerative clustering based on two-dimensional principal component analysis. The experimental results suggest (1) the number, center, and composition of clusters of spectral wavelengths and (2) the higher performance of iris multispectral recognition based on a three wavelengths-bands fusion.

Comparative analysis of classification based algorithms for diabetes diagnosis using iris images.

PubMed

Samant, Piyush; Agarwal, Ravinder

2018-01-01

Photo-diagnosis is always an intriguing area for the researchers, with the advancement of image processing and computer machine vision techniques it have become more reliable and popular in recent years. The objective of this paper is to study the change in the features of iris, particularly irregularities in the pigmentation of certain areas of the iris with respect to diabetic health of an individual. Apart from the point that iris recognition concentrates on the overall structure of the iris, diagnostic techniques emphasises the local variations in the particular area of iris. Pre-image processing techniques have been applied to extract iris and thereafter, region of interest from the extracted iris have been cropped out. In order to observe the changes in the tissue pigmentation of region of interest, statistical, texture textural and wavelet features have been extracted. At the end, a comparison of accuracies of five different classifiers has been presented to classify two subject groups of diabetic and non-diabetic. Best classification accuracy has been calculated as 89.66% by the random forest classifier. Results have been shown the effectiveness and diagnostic significance of the proposed methodology. Presented piece of work offers a novel systemic perspective of non-invasive and automatic diabetic diagnosis.

Extended depth of field system for long distance iris acquisition

NASA Astrophysics Data System (ADS)

Chen, Yuan-Lin; Hsieh, Sheng-Hsun; Hung, Kuo-En; Yang, Shi-Wen; Li, Yung-Hui; Tien, Chung-Hao

2012-10-01

Using biometric signatures for identity recognition has been practiced for centuries. Recently, iris recognition system attracts much attention due to its high accuracy and high stability. The texture feature of iris provides a signature that is unique for each subject. Currently most commercial iris recognition systems acquire images in less than 50 cm, which is a serious constraint that needs to be broken if we want to use it for airport access or entrance that requires high turn-over rate . In order to capture the iris patterns from a distance, in this study, we developed a telephoto imaging system with image processing techniques. By using the cubic phase mask positioned front of the camera, the point spread function was kept constant over a wide range of defocus. With adequate decoding filter, the blurred image was restored, where the working distance between the subject and the camera can be achieved over 3m associated with 500mm focal length and aperture F/6.3. The simulation and experimental results validated the proposed scheme, where the depth of focus of iris camera was triply extended over the traditional optics, while keeping sufficient recognition accuracy.

Toward accurate and fast iris segmentation for iris biometrics.

PubMed

He, Zhaofeng; Tan, Tieniu; Sun, Zhenan; Qiu, Xianchao

2009-09-01

Iris segmentation is an essential module in iris recognition because it defines the effective image region used for subsequent processing such as feature extraction. Traditional iris segmentation methods often involve an exhaustive search of a large parameter space, which is time consuming and sensitive to noise. To address these problems, this paper presents a novel algorithm for accurate and fast iris segmentation. After efficient reflection removal, an Adaboost-cascade iris detector is first built to extract a rough position of the iris center. Edge points of iris boundaries are then detected, and an elastic model named pulling and pushing is established. Under this model, the center and radius of the circular iris boundaries are iteratively refined in a way driven by the restoring forces of Hooke's law. Furthermore, a smoothing spline-based edge fitting scheme is presented to deal with noncircular iris boundaries. After that, eyelids are localized via edge detection followed by curve fitting. The novelty here is the adoption of a rank filter for noise elimination and a histogram filter for tackling the shape irregularity of eyelids. Finally, eyelashes and shadows are detected via a learned prediction model. This model provides an adaptive threshold for eyelash and shadow detection by analyzing the intensity distributions of different iris regions. Experimental results on three challenging iris image databases demonstrate that the proposed algorithm outperforms state-of-the-art methods in both accuracy and speed.

Edge detection techniques for iris recognition system

NASA Astrophysics Data System (ADS)

Tania, U. T.; Motakabber, S. M. A.; Ibrahimy, M. I.

2013-12-01

Nowadays security and authentication are the major parts of our daily life. Iris is one of the most reliable organ or part of human body which can be used for identification and authentication purpose. To develop an iris authentication algorithm for personal identification, this paper examines two edge detection techniques for iris recognition system. Between the Sobel and the Canny edge detection techniques, the experimental result shows that the Canny's technique has better ability to detect points in a digital image where image gray level changes even at slow rate.

The Design of a Single-Bit CMOS Image Sensor for Iris Recognition Applications

PubMed Central

Park, Keunyeol; Song, Minkyu

2018-01-01

This paper presents a single-bit CMOS image sensor (CIS) that uses a data processing technique with an edge detection block for simple iris segmentation. In order to recognize the iris image, the image sensor conventionally captures high-resolution image data in digital code, extracts the iris data, and then compares it with a reference image through a recognition algorithm. However, in this case, the frame rate decreases by the time required for digital signal conversion of multi-bit digital data through the analog-to-digital converter (ADC) in the CIS. In order to reduce the overall processing time as well as the power consumption, we propose a data processing technique with an exclusive OR (XOR) logic gate to obtain single-bit and edge detection image data instead of multi-bit image data through the ADC. In addition, we propose a logarithmic counter to efficiently measure single-bit image data that can be applied to the iris recognition algorithm. The effective area of the proposed single-bit image sensor (174 × 144 pixel) is 2.84 mm2 with a 0.18 μm 1-poly 4-metal CMOS image sensor process. The power consumption of the proposed single-bit CIS is 2.8 mW with a 3.3 V of supply voltage and 520 frame/s of the maximum frame rates. The error rate of the ADC is 0.24 least significant bit (LSB) on an 8-bit ADC basis at a 50 MHz sampling frequency. PMID:29495273

The Design of a Single-Bit CMOS Image Sensor for Iris Recognition Applications.

PubMed

Park, Keunyeol; Song, Minkyu; Kim, Soo Youn

2018-02-24

This paper presents a single-bit CMOS image sensor (CIS) that uses a data processing technique with an edge detection block for simple iris segmentation. In order to recognize the iris image, the image sensor conventionally captures high-resolution image data in digital code, extracts the iris data, and then compares it with a reference image through a recognition algorithm. However, in this case, the frame rate decreases by the time required for digital signal conversion of multi-bit digital data through the analog-to-digital converter (ADC) in the CIS. In order to reduce the overall processing time as well as the power consumption, we propose a data processing technique with an exclusive OR (XOR) logic gate to obtain single-bit and edge detection image data instead of multi-bit image data through the ADC. In addition, we propose a logarithmic counter to efficiently measure single-bit image data that can be applied to the iris recognition algorithm. The effective area of the proposed single-bit image sensor (174 × 144 pixel) is 2.84 mm² with a 0.18 μm 1-poly 4-metal CMOS image sensor process. The power consumption of the proposed single-bit CIS is 2.8 mW with a 3.3 V of supply voltage and 520 frame/s of the maximum frame rates. The error rate of the ADC is 0.24 least significant bit (LSB) on an 8-bit ADC basis at a 50 MHz sampling frequency.

Differences in iris thickness among African Americans, Caucasian Americans, Hispanic Americans, Chinese Americans, and Filipino-Americans.

PubMed

Lee, Roland Y; Huang, Guofu; Porco, Travis C; Chen, Yi-Chun; He, Mingguang; Lin, Shan C

2013-12-01

To evaluate the capability of iris thickness parameters to explain the difference in primary angle-closure glaucoma prevalence among the different racial groups. In this prospective study, 436 patients with open and narrow angles that met inclusion criteria were consecutively recruited from the UCSF general ophthalmology and glaucoma clinics to receive anterior segment optical coherence tomography imaging under standardized dark conditions. Images from 11 patients were removed due to poor visibility of the scleral spurs and the remaining images were analyzed using the Zhongshan Angle Assessment Program to assess the following measurements for the nasal and temporal angle of the anterior chamber: iris thickness at 750 and 2000 μm from the scleral spurs and the maximum iris thickness at middle one third of the iris. Iris thickness parameters were compared among and within the following 5 different racial groups: African Americans, Caucasian Americans, Hispanic Americans, Chinese Americans, and Filipino-Americans. In comparing iris parameters among the open-angle racial groups, significant differences were found for nasal iris thickness at 750 and 2000 μm from the scleral spurs in which Chinese Americans displayed the highest mean value (P=0.01, P<0.0001). Among the narrow-angle racial groups, significant difference was found for nasal iris thickness at 2000 μm from the scleral in which Chinese Americans showed the highest mean value (P<0.0001). Significant difference was also found for temporal maximum iris thickness at middle one third of the iris in which African Americans exhibited the highest mean value (P=0.021). Iris thickness was modeled as a function of angle status using linear mixed-effects regression, adjusting for age, sex, pupil diameter, spherical equivalent, ethnicity, and the use of both eyes in patients. The iris thickness difference between the narrow-angle and open-angle groups was significant (P=0.0007). Racial groups that historically showed higher prevalence of primary angle-closure glaucoma possess thicker irides.

Cataract influence on iris recognition performance

NASA Astrophysics Data System (ADS)

Trokielewicz, Mateusz; Czajka, Adam; Maciejewicz, Piotr

2014-11-01

This paper presents the experimental study revealing weaker performance of the automatic iris recognition methods for cataract-affected eyes when compared to healthy eyes. There is little research on the topic, mostly incorporating scarce databases that are often deficient in images representing more than one illness. We built our own database, acquiring 1288 eye images of 37 patients of the Medical University of Warsaw. Those images represent several common ocular diseases, such as cataract, along with less ordinary conditions, such as iris pattern alterations derived from illness or eye trauma. Images were captured in near-infrared light (used in biometrics) and for selected cases also in visible light (used in ophthalmological diagnosis). Since cataract is a disorder that is most populated by samples in the database, in this paper we focus solely on this illness. To assess the extent of the performance deterioration we use three iris recognition methodologies (commercial and academic solutions) to calculate genuine match scores for healthy eyes and those influenced by cataract. Results show a significant degradation in iris recognition reliability manifesting by worsening the genuine scores in all three matchers used in this study (12% of genuine score increase for an academic matcher, up to 175% of genuine score increase obtained for an example commercial matcher). This increase in genuine scores affected the final false non-match rate in two matchers. To our best knowledge this is the only study of such kind that employs more than one iris matcher, and analyzes the iris image segmentation as a potential source of decreased reliability

A novel iris localization algorithm using correlation filtering

NASA Astrophysics Data System (ADS)

Pohit, Mausumi; Sharma, Jitu

2015-06-01

Fast and efficient segmentation of iris from the eye images is a primary requirement for robust database independent iris recognition. In this paper we have presented a new algorithm for computing the inner and outer boundaries of the iris and locating the pupil centre. Pupil-iris boundary computation is based on correlation filtering approach, whereas iris-sclera boundary is determined through one dimensional intensity mapping. The proposed approach is computationally less extensive when compared with the existing algorithms like Hough transform.

Simultaneous observations of Ellerman bombs by NST and IRIS

NASA Astrophysics Data System (ADS)

Kim, Y. H.; Yurchyshyn, V.; Cho, I. H.; Lee, J.; Park, Y. D.; Yang, H.; Ahn, K.; Goode, P.

2015-12-01

In this study, we present the simultaneous observations of Ellerman bombs made by New Solar Telescope (NST) of Big Bear Solar Observatory (BBSO) and Interface Region Imaging Spectrograph (IRIS) in space. The data obtained during joint NST-IRIS observations on 30 and 31 in July 2014. We observed two representative events on both days. The first one was a relatively weak Ellerman bomb occurred around 19:20 UT on 30 July 2014. IRIS observed this event by sit-and-stare mode thus we analyzed high cadence spectral data and slit-jaw data simultaneously. We found that this event was a hot explosion that occurred by magnetic reconnection in the lower atmosphere of the Sun. The second event was quite strong Ellerman bomb (20:20 UT on 31 July 2014) that is well observed by NST FISS (Fast Imaging Solar Spectrograph), while there was no IRIS spectral data. We had IRIS slit-jaw data only. The Ellerman bomb was clearly coincident with the IRIS brightening at the same location. Since the Ellerman bombs are usually believed to occur in the photosphere with no coronal emission, it should be explained its higher atmospheric emission in IRIS data. We will present the result of simultaneous observations by IRIS and NST instruments and discuss physical connection between Ellerman bombs and IRIS brightenings.

A novel iris transillumination grading scale allowing flexible assessment with quantitative image analysis and visual matching.

PubMed

Wang, Chen; Brancusi, Flavia; Valivullah, Zaheer M; Anderson, Michael G; Cunningham, Denise; Hedberg-Buenz, Adam; Power, Bradley; Simeonov, Dimitre; Gahl, William A; Zein, Wadih M; Adams, David R; Brooks, Brian

2018-01-01

To develop a sensitive scale of iris transillumination suitable for clinical and research use, with the capability of either quantitative analysis or visual matching of images. Iris transillumination photographic images were used from 70 study subjects with ocular or oculocutaneous albinism. Subjects represented a broad range of ocular pigmentation. A subset of images was subjected to image analysis and ranking by both expert and nonexpert reviewers. Quantitative ordering of images was compared with ordering by visual inspection. Images were binned to establish an 8-point scale. Ranking consistency was evaluated using the Kendall rank correlation coefficient (Kendall's tau). Visual ranking results were assessed using Kendall's coefficient of concordance (Kendall's W) analysis. There was a high degree of correlation among the image analysis, expert-based and non-expert-based image rankings. Pairwise comparisons of the quantitative ranking with each reviewer generated an average Kendall's tau of 0.83 ± 0.04 (SD). Inter-rater correlation was also high with Kendall's W of 0.96, 0.95, and 0.95 for nonexpert, expert, and all reviewers, respectively. The current standard for assessing iris transillumination is expert assessment of clinical exam findings. We adapted an image-analysis technique to generate quantitative transillumination values. Quantitative ranking was shown to be highly similar to a ranking produced by both expert and nonexpert reviewers. This finding suggests that the image characteristics used to quantify iris transillumination do not require expert interpretation. Inter-rater rankings were also highly similar, suggesting that varied methods of transillumination ranking are robust in terms of producing reproducible results.

[Use of computer technologies for studying the morphological characteristics of the iris color in anthropology].

PubMed

Dorofeeva, A A; Khrustalev, A V; Krylov, Iu V; Bocharov, D A; Negasheva, M A

2010-01-01

Digital images of the iris were received for study peculiarities of the iris color during the anthropological examination of 578 students aged 16-24 years. Simultaneously with the registration of the digital images, the visual assessment of the eye color was carried out using the traditional scale of Bunak, based on 12 ocular prostheses. Original software for automatic determination of the iris color based on 12 classes scale of Bunak was designed, and computer version of that scale was developed. The software proposed allows to conduct the determination of the iris color with high validity based on numerical evaluation; its application may reduce the bias due to subjective assessment and methodological divergences of the different researchers. The software designed for automatic determination of the iris color may help develop both theoretical and applied anthropology, it may be used in forensic and emergency medicine, sports medicine, medico-genetic counseling and professional selection.

A Novel Anti-Spoofing Solution for Iris Recognition Toward Cosmetic Contact Lens Attack Using Spectral ICA Analysis.

PubMed

Hsieh, Sheng-Hsun; Li, Yung-Hui; Wang, Wei; Tien, Chung-Hao

2018-03-06

In this study, we maneuvered a dual-band spectral imaging system to capture an iridal image from a cosmetic-contact-lens-wearing subject. By using the independent component analysis to separate individual spectral primitives, we successfully distinguished the natural iris texture from the cosmetic contact lens (CCL) pattern, and restored the genuine iris patterns from the CCL-polluted image. Based on a database containing 200 test image pairs from 20 CCL-wearing subjects as the proof of concept, the recognition accuracy (False Rejection Rate: FRR) was improved from FRR = 10.52% to FRR = 0.57% with the proposed ICA anti-spoofing scheme.

Hyperspectral imaging of the human iris

NASA Astrophysics Data System (ADS)

Di Cecilia, Luca; Marazzi, Francesco; Rovati, Luigi

2017-07-01

We describe an optical system and a method for measuring the human iris spectral reflectance in vivo by hyperspectral imaging analysis. It is important to monitor age-related changes in the reflectance properties of the iris as they are a prognostic factor for several eye pathologies. In this paper, we report the outcomes of our most recent research, resulting from the improvement of our imaging system. In particular, a custom tunable light source was developed: the images are now acquired in the spectral range 440 - 900 nm. With this system, we are able to obtain a spectral resolution of 20nm, while each image of 2048 x 1536 pixels has a spatial resolution of 10.7 μm. The results suggest that the instrument could be exploited for measuring iris pigmentation changes over time. These measurements could provide new diagnostic capabilities in ophthalmology. Further studies are required to determine the measurements' repeatability and to develop a spectral library for results evaluation and to detect differences among subsequent screenings of the same subject.

Texture Feature Extraction and Classification for Iris Diagnosis

NASA Astrophysics Data System (ADS)

Ma, Lin; Li, Naimin

Appling computer aided techniques in iris image processing, and combining occidental iridology with the traditional Chinese medicine is a challenging research area in digital image processing and artificial intelligence. This paper proposes an iridology model that consists the iris image pre-processing, texture feature analysis and disease classification. To the pre-processing, a 2-step iris localization approach is proposed; a 2-D Gabor filter based texture analysis and a texture fractal dimension estimation method are proposed for pathological feature extraction; and at last support vector machines are constructed to recognize 2 typical diseases such as the alimentary canal disease and the nerve system disease. Experimental results show that the proposed iridology diagnosis model is quite effective and promising for medical diagnosis and health surveillance for both hospital and public use.

Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content (LWC)

NASA Technical Reports Server (NTRS)

Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

2011-01-01

This study presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetic active radiation (PAR) absorbed by chlorophyll of a canopy (fAPAR(sub chl)) and leaf water content (LWC), for future HyspIRI implementation at 60 m spatial resolution. For this, we used existing 30 m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRI-like images were atmospherically corrected to obtain surface reflectance, and spectrally resampled to produce 60 m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest[1]. With this study, we provide additional evidence that the fAPARchl product is more realistic for describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPAR(sub canopy)), and thus should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle studies and ecosystem studies.

[The automatic iris map overlap technology in computer-aided iridiagnosis].

PubMed

He, Jia-feng; Ye, Hu-nian; Ye, Miao-yuan

2002-11-01

In the paper, iridology and computer-aided iridiagnosis technologies are briefly introduced and the extraction method of the collarette contour is then investigated. The iris map can be overlapped on the original iris image based on collarette contour extraction. The research on collarette contour extraction and iris map overlap is of great importance to computer-aided iridiagnosis technologies.

The Priority of Road Rehabilitation in Karanganyar Regency Using IRI Estimation from Roadroid

NASA Astrophysics Data System (ADS)

Achmadi, F.; Suprapto, M.; Setyawan, A.

2017-02-01

The IRI (International Roughness Index) is a road roughness index commonly obtained from measured longitudinal road profiles. This is one of the functional performance a surface of road pavement. Therefore, needs to be done evaluation and monitoring periodically to getting priority of road rehabilitation right on target. The IRI standard has commonly been used worldwide for evaluating road system. The Roadroid is an application to measure road quality with a website to view road quality. It is designed for Android smartphones, so we can easily measure and monitor the road and also use the camera for GPS-tagged photo. By using the built-in vibration sensor in smartphones, it is possible to collect IRI value which can be an indicator road conditions. This study attempts to explain the priority of road rehabilitation in Karanganyar Regency. The location of the study focused on a collector street (primary, secondary and locally road). The result of IRI estimation will be combined with other aspects that influences; land use, policy, the connectivity of road and traffic average daily. Based on IRI estimation using Roadroid, the road conditions in Karanganyar Regency can be described 59,60% were good (IRI<4,5) 21,30% fair (4,512).

A Novel Anti-Spoofing Solution for Iris Recognition Toward Cosmetic Contact Lens Attack Using Spectral ICA Analysis

PubMed Central

Hsieh, Sheng-Hsun; Wang, Wei; Tien, Chung-Hao

2018-01-01

In this study, we maneuvered a dual-band spectral imaging system to capture an iridal image from a cosmetic-contact-lens-wearing subject. By using the independent component analysis to separate individual spectral primitives, we successfully distinguished the natural iris texture from the cosmetic contact lens (CCL) pattern, and restored the genuine iris patterns from the CCL-polluted image. Based on a database containing 200 test image pairs from 20 CCL-wearing subjects as the proof of concept, the recognition accuracy (False Rejection Rate: FRR) was improved from FRR = 10.52% to FRR = 0.57% with the proposed ICA anti-spoofing scheme. PMID:29509692

Trade off between variable and fixed size normalization in orthogonal polynomials based iris recognition system.

PubMed

Krishnamoorthi, R; Anna Poorani, G

2016-01-01

Iris normalization is an important stage in any iris biometric, as it has a propensity to trim down the consequences of iris distortion. To indemnify the variation in size of the iris owing to the action of stretching or enlarging the pupil in iris acquisition process and camera to eyeball distance, two normalization schemes has been proposed in this work. In the first method, the iris region of interest is normalized by converting the iris into the variable size rectangular model in order to avoid the under samples near the limbus border. In the second method, the iris region of interest is normalized by converting the iris region into a fixed size rectangular model in order to avoid the dimensional discrepancies between the eye images. The performance of the proposed normalization methods is evaluated with orthogonal polynomials based iris recognition in terms of FAR, FRR, GAR, CRR and EER.

Performance evaluation of the CT component of the IRIS PET/CT preclinical tomograph

NASA Astrophysics Data System (ADS)

Panetta, Daniele; Belcari, Nicola; Tripodi, Maria; Burchielli, Silvia; Salvadori, Piero A.; Del Guerra, Alberto

2016-01-01

In this paper, we evaluate the physical performance of the CT component of the IRIS scanner, a novel combined PET/CT scanner for preclinical imaging. The performance assessment is based on phantom measurement for the determination of image quality parameters (spatial resolution, linearity, geometric accuracy, contrast to noise ratio) and reproducibility in dynamic (4D) imaging. The CTDI100 has been measured free in air with a pencil ionization chamber, and the animal dose was calculated using Monte Carlo derived conversion factors taken from the literature. The spatial resolution at the highest quality protocol was 6.9 lp/mm at 10% of the MTF, using the smallest reconstruction voxel size of 58.8 μm. The accuracy of the reconstruction voxel size was within 0.1%. The linearity of the CT numbers as a function of the concentration of iodine was very good, with R2>0.996 for all the tube voltages. The animal dose depended strongly on the scanning protocol, ranging from 158 mGy for the highest quality protocol (2 min, 80 kV) to about 12 mGy for the fastest protocol (7.3 s, 80 kV). In 4D dynamic modality, the maximum scanning rate reached was 3.1 frames per minute, using a short-scan protocol with 7.3 s of scan time per frame at the isotropic voxel size of 235 μm. The reproducibility of the system was high throughout the 10 frames acquired in dynamic modality, with a standard deviation of the CT values of all frames <8 HU and an average spatial reproducibility within 30% of the voxel size across all the field of view. Example images obtained during animal experiments are also shown.

Real-time digital imaging of leukocyte-endothelial interaction in ischemia-reperfusion injury (IRI) of the rat cremaster muscle.

PubMed

Thiele, Jan R; Goerendt, Kurt; Stark, G Bjoern; Eisenhardt, Steffen U

2012-08-05

Ischemia-reperfusion injury (IRI) has been implicated in a large array of pathological conditions such as cerebral stroke, myocardial infarction, intestinal ischemia as well as following transplant and cardiovascular surgery. Reperfusion of previously ischemic tissue, while essential for the prevention of irreversible tissue injury, elicits excessive inflammation of the affected tissue. Adjacent to the production of reactive oxygen species, activation of the complement system and increased microvascular permeability, the activation of leukocytes is one of the principle actors in the pathological cascade of inflammatory tissue damage during reperfusion. Leukocyte activation is a multistep process consisting of rolling, firm adhesion and transmigration and is mediated by a complex interaction between adhesion molecules in response to chemoattractants such as complement factors, chemokines, or platelet-activating factor. While leukocyte rolling in postcapillary venules is predominantly mediated by the interaction of selectins with their counter ligands, firm adhesion of leukocytes to the endothelium is selectin-controlled via binding to intercellular adhesion molecules (ICAM) and vascular cellular adhesion molecules (VCAM). Gold standard for the in vivo observation of leukocyte-endothelial interaction is the technique of intravital microscopy, first described in 1968. Though various models of IRI (ischemia-reperfusion injury) have been described for various organs, only few are suitable for direct visualization of leukocyte recruitment in the microvascular bed on a high level of image quality. We here promote the digital intravital epifluorescence microscopy of the postcapillary venule in the cremasteric microcirculation of the rat as a convenient method to qualitatively and quantitatively analyze leukocyte recruitment for IRI-research in striated muscle tissue and provide a detailed manual for accomplishing the technique. We further illustrate common pitfalls and provide useful tips which should enable the reader to truly appreciate, and safely perform the method. In a step by step protocol we depict how to get started with respiration controlled anesthesia under sufficient monitoring to keep the animal firmly anesthetized for longer periods of time. We then describe the cremasteric preparation as a thin flat sheet for outstanding optical resolution and provide a protocol for leukocyte imaging in IRI that has been well established in our laboratories.

DCT-based iris recognition.

PubMed

Monro, Donald M; Rakshit, Soumyadip; Zhang, Dexin

2007-04-01

This paper presents a novel iris coding method based on differences of discrete cosine transform (DCT) coefficients of overlapped angular patches from normalized iris images. The feature extraction capabilities of the DCT are optimized on the two largest publicly available iris image data sets, 2,156 images of 308 eyes from the CASIA database and 2,955 images of 150 eyes from the Bath database. On this data, we achieve 100 percent Correct Recognition Rate (CRR) and perfect Receiver-Operating Characteristic (ROC) Curves with no registered false accepts or rejects. Individual feature bit and patch position parameters are optimized for matching through a product-of-sum approach to Hamming distance calculation. For verification, a variable threshold is applied to the distance metric and the False Acceptance Rate (FAR) and False Rejection Rate (FRR) are recorded. A new worst-case metric is proposed for predicting practical system performance in the absence of matching failures, and the worst case theoretical Equal Error Rate (EER) is predicted to be as low as 2.59 x 10(-4) on the available data sets.

Scheimpflug with computational imaging to extend the depth of field of iris recognition systems

NASA Astrophysics Data System (ADS)

Sinharoy, Indranil

Despite the enormous success of iris recognition in close-range and well-regulated spaces for biometric authentication, it has hitherto failed to gain wide-scale adoption in less controlled, public environments. The problem arises from a limitation in imaging called the depth of field (DOF): the limited range of distances beyond which subjects appear blurry in the image. The loss of spatial details in the iris image outside the small DOF limits the iris image capture to a small volume-the capture volume. Existing techniques to extend the capture volume are usually expensive, computationally intensive, or afflicted by noise. Is there a way to combine the classical Scheimpflug principle with the modern computational imaging techniques to extend the capture volume? The solution we found is, surprisingly, simple; yet, it provides several key advantages over existing approaches. Our method, called Angular Focus Stacking (AFS), consists of capturing a set of images while rotating the lens, followed by registration, and blending of the in-focus regions from the images in the stack. The theoretical underpinnings of AFS arose from a pair of new and general imaging models we developed for Scheimpflug imaging that directly incorporates the pupil parameters. The model revealed that we could register the images in the stack analytically if we pivot the lens at the center of its entrance pupil, rendering the registration process exact. Additionally, we found that a specific lens design further reduces the complexity of image registration making AFS suitable for real-time performance. We have demonstrated up to an order of magnitude improvement in the axial capture volume over conventional image capture without sacrificing optical resolution and signal-to-noise ratio. The total time required for capturing the set of images for AFS is less than the time needed for a single-exposure, conventional image for the same DOF and brightness level. The net reduction in capture time can significantly relax the constraints on subject movement during iris acquisition, making it less restrictive.

KSC-2013-2730

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit is moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2731

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit is moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2726

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit is moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2733

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit is moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2734

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit is moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2732

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit is moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2669

NASA Image and Video Library

2013-06-11

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June is seen in a hangar at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2668

NASA Image and Video Library

2013-06-11

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June is seen in a hangar at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2666

NASA Image and Video Library

2013-06-11

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June is seen in a hangar at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2665

NASA Image and Video Library

2013-06-11

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June is seen in a hangar at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2667

NASA Image and Video Library

2013-06-11

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June is seen in a hangar at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2727

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit is moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

Developments in Seismic Data Quality Assessment Using MUSTANG at the IRIS DMC

NASA Astrophysics Data System (ADS)

Sharer, G.; Keyson, L.; Templeton, M. E.; Weertman, B.; Smith, K.; Sweet, J. R.; Tape, C.; Casey, R. E.; Ahern, T.

2017-12-01

MUSTANG is the automated data quality metrics system at the IRIS Data Management Center (DMC), designed to help characterize data and metadata "goodness" across the IRIS data archive, which holds 450 TB of seismic and related earth science data spanning the past 40 years. It calculates 46 metrics ranging from sample statistics and miniSEED state-of-health flag counts to Power Spectral Densities (PSDs) and Probability Density Functions (PDFs). These quality measurements are easily and efficiently accessible to users through the use of web services, which allows users to make requests not only by station and time period but also to filter the results according to metric values that match a user's data requirements. Results are returned in a variety of formats, including XML, JSON, CSV, and text. In the case of PSDs and PDFs, results can also be retrieved as plot images. In addition, there are several user-friendly client tools available for exploring and visualizing MUSTANG metrics: LASSO, MUSTANG Databrowser, and MUSTANGular. Over the past year we have made significant improvements to MUSTANG. We have nearly complete coverage over our archive for broadband channels with sample rates of 20-200 sps. With this milestone achieved, we are now expanding to include higher sample rate, short-period, and strong-motion channels. Data availability metrics will soon be calculated when a request is made which guarantees that the information reflects the current state of the archive and also allows for more flexibility in content. For example, MUSTANG will be able to return a count of gaps for any arbitrary time period instead of being limited to 24 hour spans. We are also promoting the use of data quality metrics beyond the IRIS archive through our recent release of ISPAQ, a Python command-line application that calculates MUSTANG-style metrics for users' local miniSEED files or for any miniSEED data accessible through FDSN-compliant web services. Finally, we will explore how researchers are using MUSTANG in real-world situations to select data, improve station data quality, anticipate station outages and servicing, and characterize site noise and environmental conditions.

The concave iris in pigment dispersion syndrome.

PubMed

Liu, Lance; Ong, Ee Lin; Crowston, Jonathan

2011-01-01

To visualize the changes of the iris contour in patients with pigment dispersion syndrome after blinking, accommodation, and pharmacologic miosis using anterior segment optical coherence tomography. Observational case series. A total of 33 eyes of 20 patients with pigment dispersion syndrome. Each eye was imaged along the horizontal 0- to 180-degree meridian using the Visante Anterior Segment Imaging System (Carl Zeiss Meditec, Dublin, CA). Scans were performed at baseline and after focusing on an internal fixation target for 5 minutes, forced blinking, accommodation, and pharmacologic miosis with pilocarpine 2%. Quantitative analysis of the changes in the iris configuration. After 5 minutes of continual fixation, the iris became planar with the mean ± standard deviation curvature decreasing from 214 ± 74 μm to 67 ± 76 μm (P < 0.05). The iris remained planar in all patients with pigment dispersion syndrome after forced blinking, but the iris concavity recovered to 227 ± 113 μm (P = 0.34) and 238 ± 119 μm (P = 0.19) with the -3.0 and -6.0 diopter lenses, respectively. Pilocarpine-induced miosis caused the iris to assume a planar configuration in all subjects. This study shows that the iris in pigment dispersion syndrome assumes a planar configuration when fixating and that the concavity of the iris surface is not restored by blinking. Accommodation restored the iris concavity, suggesting that the posterior curvature of the iris in pigment dispersion syndrome is induced and probably maintained, at least in part, by accommodation. Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Qualitative evaluation of the iris and ciliary body by ultrasound biomicroscopy in subjects with angle closure.

PubMed

Ku, Judy Y; Nongpiur, Monisha E; Park, Judy; Narayanaswamy, Arun K; Perera, Shamira A; Tun, Tin A; Kumar, Rajesh S; Baskaran, Mani; Aung, Tin

2014-12-01

To qualitatively analyze anterior chamber structures imaged by ultrasound biomicroscopy (UBM) in primary angle-closure patients. Subjects diagnosed as primary angle-closure suspect (PACS), primary angle-closure glaucoma (PACG), and previous acute primary angle closure (APAC) were recruited prospectively along with a group of normal controls. UBM was performed under standardized dark room conditions and qualitative assessment was carried out using a set of reference photographs of standard UBM images to categorize the various anatomic features related to angle configuration. These included overall and basal iris thicknesses, iris convexity, iris angulation, ciliary body size, and ciliary sulcus. A total of 60 PACS, 114 PACG, 41 APAC, and 33 normal controls were included. Patients were predominantly older Chinese females. After controlling the confounding effect of age and sex, eyes with overall thicker irides [medium odds ratio (OR) 3.58, thick OR 2.84] when compared with thin irides have a significantly higher likelihood of having PACS/PACG/APAC versus controls. Thicker basal iris component (medium OR 4.13, thick OR 3.39) also have higher likelihood of having angle closure when compared with thin basal iris thickness. Subjects with basal iris insertion, mild iris angulation, and large ciliary body have a higher OR of having angle closure. In contrast, the presence/absence of a ciliary sulcus did not influence the likelihood of angle closure. Eyes with thicker overall and basal iris thicknesses are more likely to have angle closure than controls. Other features that increase the likelihood of angle closure include basal iris insertion, mild iris angulation, and large ciliary body.

Effect of cataract surgery and pupil dilation on iris pattern recognition for personal authentication.

PubMed

Dhir, L; Habib, N E; Monro, D M; Rakshit, S

2010-06-01

The purpose of this study was to investigate the effect of cataract surgery and pupil dilation on iris pattern recognition for personal authentication. Prospective non-comparative cohort study. Images of 15 subjects were captured before (enrolment), and 5, 10, and 15 min after instillation of mydriatics before routine cataract surgery. After cataract surgery, images were captured 2 weeks thereafter. Enrolled and test images (after pupillary dilation and after cataract surgery) were segmented to extract the iris. This was then unwrapped onto a rectangular format for normalization and a novel method using the Discrete Cosine Transform was applied to encode the image into binary bits. The numerical difference between two iris codes (Hamming distance, HD) was calculated. The HD between identification and enrolment codes was used as a score and was compared with a confidence threshold for specific equipment, giving a match or non-match result. The Correct Recognition Rate (CRR) and Equal Error Rates (EERs) were calculated to analyse overall system performance. After cataract surgery, perfect identification and verification was achieved, with zero false acceptance rate, zero false rejection rate, and zero EER. After pupillary dilation, non-elastic deformation occurs and a CRR of 86.67% and EER of 9.33% were obtained. Conventional circle-based localization methods are inadequate. Matching reliability decreases considerably with increase in pupillary dilation. Cataract surgery has no effect on iris pattern recognition, whereas pupil dilation may be used to defeat an iris-based authentication system.

Spatial Light Modulator Would Serve As Electronic Iris

NASA Technical Reports Server (NTRS)

Gutow, David A.

1991-01-01

In proposed technique for controlling brightness of image formed by lens, spatial light modulator serves as segmented, electronically variable aperture. Offers several advantages: spatial light modulator controlled remotely and responds faster than motorized iris or other remotely controlled mechanical iris. Unlike iris, modulator also configured so as not to vary depth of field appreciably. Unlike lead lanthanum zirconate titanate crystal, spatial light modulator does not require high voltage.

Predictors of intraocular pressure change after phacoemulsification in patients with pseudoexfoliation syndrome.

PubMed

Moghimi, Sasan; Johari, Mohammadkarim; Mahmoudi, Alireza; Chen, Rebecca; Mazloumi, Mehdi; He, Mingguang; Lin, Shan C

2017-03-01

To evaluate anterior chamber biometric factors and intraoperative metrics associated with the intraocular pressure (IOP) reduction after phacoemulsification in non-glaucomatous pseudoexfoliative syndrome (PXS) eyes. Thirty-three patients were enrolled in this prospective interventional study. Images were excluded if they had poor quality, poor perpendicularity or inability to locate sclera spurs. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness, iris area, iris curvature, lens vault, angle opening distance (AOD500, AOD750) and trabecular iris space area (TISA500, TISA750) were measured in qualified images using the Zhongshan Angle Assessment Program and compared preoperatively and 3 months postoperatively. Cumulative dissipated energy (CDE), aspiration time and infusion fluid usage during cataract surgery were obtained from the phacoemulsification machine's metrics record. Postoperative IOP change was compared with these anatomical and intraoperative metric parameters. Mean IOP was 18.1±3.4 mm Hg preoperatively and decreased by 3.3 mm Hg (18%) to 14.8±3.6 mm Hg at 3 months postoperatively (p<0.001). All angle parameters, ACD and ACA increased significantly postoperatively (p<0.001 for all) and iris curvature decreased (p<0.001). In univariate analysis, preoperative IOP (B=-0.668, p=0.002), infusion fluid usage (B=-0.040, p=0.04) and aspiration time (B=-0.045, p=0.003) were negatively associated with IOP decrease after phacoemulsification. Changes in IOP did not demonstrate significant associations with CDE measurements or anterior segment optical coherence tomography measurements, including preoperative angle, iris or anterior segment parameters. In the final multivariate regression model, preoperative IOP (B=-0.668, p=0.002) and infusion fluid usage (B=-0.041, p=0.04) were significantly associated with IOP drop and together can predict 45.1% (p=0.002) of the variability in IOP change. Non-glaucomatous patients with PXS experience moderate IOP reduction following phacoemulsification, and this effect is correlated with preoperative IOP, aspiration time and infusion fluid used intraoperatively. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Shape Adaptive, Robust Iris Feature Extraction from Noisy Iris Images

PubMed Central

Ghodrati, Hamed; Dehghani, Mohammad Javad; Danyali, Habibolah

2013-01-01

In the current iris recognition systems, noise removing step is only used to detect noisy parts of the iris region and features extracted from there will be excluded in matching step. Whereas depending on the filter structure used in feature extraction, the noisy parts may influence relevant features. To the best of our knowledge, the effect of noise factors on feature extraction has not been considered in the previous works. This paper investigates the effect of shape adaptive wavelet transform and shape adaptive Gabor-wavelet for feature extraction on the iris recognition performance. In addition, an effective noise-removing approach is proposed in this paper. The contribution is to detect eyelashes and reflections by calculating appropriate thresholds by a procedure called statistical decision making. The eyelids are segmented by parabolic Hough transform in normalized iris image to decrease computational burden through omitting rotation term. The iris is localized by an accurate and fast algorithm based on coarse-to-fine strategy. The principle of mask code generation is to assign the noisy bits in an iris code in order to exclude them in matching step is presented in details. An experimental result shows that by using the shape adaptive Gabor-wavelet technique there is an improvement on the accuracy of recognition rate. PMID:24696801

Shape adaptive, robust iris feature extraction from noisy iris images.

PubMed

Ghodrati, Hamed; Dehghani, Mohammad Javad; Danyali, Habibolah

2013-10-01

In the current iris recognition systems, noise removing step is only used to detect noisy parts of the iris region and features extracted from there will be excluded in matching step. Whereas depending on the filter structure used in feature extraction, the noisy parts may influence relevant features. To the best of our knowledge, the effect of noise factors on feature extraction has not been considered in the previous works. This paper investigates the effect of shape adaptive wavelet transform and shape adaptive Gabor-wavelet for feature extraction on the iris recognition performance. In addition, an effective noise-removing approach is proposed in this paper. The contribution is to detect eyelashes and reflections by calculating appropriate thresholds by a procedure called statistical decision making. The eyelids are segmented by parabolic Hough transform in normalized iris image to decrease computational burden through omitting rotation term. The iris is localized by an accurate and fast algorithm based on coarse-to-fine strategy. The principle of mask code generation is to assign the noisy bits in an iris code in order to exclude them in matching step is presented in details. An experimental result shows that by using the shape adaptive Gabor-wavelet technique there is an improvement on the accuracy of recognition rate.

TECHNICAL BRIEF: Isolation of total DNA from postmortem human eye tissues and quality comparison between iris and retina

PubMed Central

Wang, Jay Ching Chieh; Wang, Aikun; Gao, Jiangyuan; Cao, Sijia; Samad, Idris; Zhang, Dean; Ritland, Carol; Cui, Jing Z.

2012-01-01

Background Recent genomic technologies have propelled our understanding of the mechanisms underlying complex eye diseases such as age-related macular degeneration (AMD). Genotyping postmortem eye tissues for known single nucleotide polymorphisms (SNPs) associated with AMD may prove valuable, especially when combined with information obtained through other methods such as immunohistochemistry, western blot, enzyme-linked immunosorbent assay (ELISA), and proteomics. Initially intending to genotype postmortem eye tissues for AMD-related SNPs, our group became interested in isolating and comparing the quality of DNA from the iris and retina of postmortem donor eyes. Since there is no previously published protocol in the literature on this topic, we present a protocol suitable for isolating high-quality DNA from postmortem eye tissues for genomic studies. Methods DNA from 33 retinal samples and 35 iris samples was extracted using the phenol-chloroform-isoamyl method from postmortem donor eye tissues. The quantity of DNA was measured with a spectrophotometer while the quality was checked using gel electrophoresis. The DNA samples were then amplified with PCR for the complement factor H (CFH) gene. The purified amplified products were then genotyped for the SNPs in the CFH gene. Results Regarding concentration, the retina yielded 936 ng/μl of DNA, while the iris yielded 78 ng/μl of DNA. Retinal DNA was also purer than iris DNA (260/280=1.78 vs. 1.46, respectively), and produced superior PCR results. Retinal tissue yielded significantly more DNA than the iris tissue per mg of sample (21.7 ng/μl/mg vs. 7.42 ng/μl/mg). Retinal DNA can be readily amplified with PCR, while iris DNA can also be amplified by adding bovine serum albumin. Overall, retinal tissues yielded DNA of superior quality, quantity, and suitability for genotyping and genomic studies. Conclusions The protocol presented here provides a clear and reliable method for isolating total DNA from postmortem eye tissues. Retinal tissue provides DNA of excellent quantity and quality for genotyping and downstream genomic studies. However, DNA isolated from iris tissues, and treated with bovine serum albumin, may also be a valuable source of DNA for genotyping and genomic studies. PMID:23288996

Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content(LWC)

NASA Technical Reports Server (NTRS)

Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

2012-01-01

This paper presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetically active radiation (PAR) absorbed by chlorophyll of a canopy (fAPARchl) and leaf water content (LWC), for future HyspIRI implementation at 60-m spatial resolution. For this, we used existing 30-m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRIlike images were atmospherically corrected to obtain surface reflectance and spectrally resampled to produce 60-m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest. With this paper, we provide additional evidence that the fAPARchl product is more realistic in describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPARcanopy), and thus, it should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle and ecosystem studies.

Iris recognition using possibilistic fuzzy matching on local features.

PubMed

Tsai, Chung-Chih; Lin, Heng-Yi; Taur, Jinshiuh; Tao, Chin-Wang

2012-02-01

In this paper, we propose a novel possibilistic fuzzy matching strategy with invariant properties, which can provide a robust and effective matching scheme for two sets of iris feature points. In addition, the nonlinear normalization model is adopted to provide more accurate position before matching. Moreover, an effective iris segmentation method is proposed to refine the detected inner and outer boundaries to smooth curves. For feature extraction, the Gabor filters are adopted to detect the local feature points from the segmented iris image in the Cartesian coordinate system and to generate a rotation-invariant descriptor for each detected point. After that, the proposed matching algorithm is used to compute a similarity score for two sets of feature points from a pair of iris images. The experimental results show that the performance of our system is better than those of the systems based on the local features and is comparable to those of the typical systems.

Effects of Iris Surface Curvature on Iris Recognition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, Joseph T; Flynn, Patrick J; Bowyer, Kevin W

To focus on objects at various distances, the lens of the eye must change shape to adjust its refractive power. This change in lens shape causes a change in the shape of the iris surface which can be measured by examining the curvature of the iris. This work isolates the variable of iris curvature in the recognition process and shows that differences in iris curvature degrade matching ability. To our knowledge, no other work has examined the effects of varying iris curvature on matching ability. To examine this degradation, we conduct a matching experiment across pairs of images with varyingmore » degrees of iris curvature differences. The results show a statistically signi cant degradation in matching ability. Finally, the real world impact of these ndings is discussed« less

KSC-2013-2627

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Detail of the Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2620

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Detail of the Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2625

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Detail of the Orbital Sciences Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

Waardenburg syndrome: iris and choroidal hypopigmentation: findings on anterior and posterior segment imaging.

PubMed

Shields, Carol L; Nickerson, Stephanie J; Al-Dahmash, Saad; Shields, Jerry A

2013-09-01

Waardenburg syndrome typically manifests with congenital iris pigmentary abnormalities, but careful inspection can reveal additional posterior uveal pigmentary abnormalities. To demonstrate iris and choroidal hypopigmentation in patients with Waardenburg syndrome. Retrospective review of 7 patients referred for evaluation of presumed ocular melanocytosis. To describe the clinical and imaging features of the anterior and posterior uvea. In all patients, the diagnosis of Waardenburg syndrome was established. The nonocular features included white forelock in 4 of 7 (57%), tubular nose in 5 of 6 (83%), and small nasal alae in 5 of 6 (83%) patients. In 2 patients, a hearing deficit was documented on audiology testing. Family history of Waardenburg syndrome was elicited in 5 of 7 (71%) patients. Ocular features (7 patients) included telecanthus in 5 (71%), synophrys in 2 (29%), iris hypopigmentation in 5 (71%), and choroidal hypopigmentation in 5 (71%) patients. No patient had muscle contractures or Hirschsprung disease. Visual acuity was 20/20 to 20/50 in all patients. Iris hypopigmentation in 8 eyes was sector in 6 (75%) and diffuse (complete) in 2 (25%). Choroidal hypopigmentation in 9 eyes (100%) showed a sector pattern in 6 (67%) and a diffuse pattern in 3 (33%). Anterior segment optical coherence tomography revealed the hypopigmented iris to be thinner and with shallower crypts than the normal iris. Posterior segment optical coherence tomography showed a normal retina in all patients, but the subfoveal choroid in the hypopigmented region was slightly thinner (mean, 197 μm) compared with the opposite normal choroid (243 μm). Fundus autofluorescence demonstrated mild hyperautofluorescence (scleral unmasking) in hypopigmented choroid and no lipofuscin abnormality. Waardenburg syndrome manifests hypopigmentation of the iris and choroid with imaging features showing a slight reduction in the thickness of the affected tissue.

KSC-2013-2910

NASA Image and Video Library

2013-06-25

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, NASA hosted a prelaunch mission briefing on the Interface Region Imaging Spectrograph, or IRIS, solar observatory scheduled to launch on a Pegasus XL rocket. Participating in the news conference are George Diller, NASA Public Affairs, Dr. S. Pete Worden, director of NASA's Ames Research Center in Calif., Jeffrey Newmark, IRIS Program scientist at NASA Headquarters in Washington D.C., and Alan Title, IRIS principal investigator with Lockheed Martin. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/ Daniel Casper

High-frequency ultrasound measurements of the normal ciliary body and iris.

PubMed

Garcia, Julian P S; Spielberg, Leigh; Finger, Paul T

2011-01-01

To determine the normal ultrasonographic thickness of the iris and ciliary body. This prospective 35-MHz ultrasonographic study included 80 normal eyes of 40 healthy volunteers. The images were obtained at the 12-, 3-, 6-, and 9-o'clock radial meridians, measured at three locations along the radial length of the iris and at the thickest section of the ciliary body. Mixed model was used to estimate eye site-adjusted means and standard errors and to test the statistical difference of adjusted results. Parameters included mean thickness, standard deviation, and range. Mean thicknesses at the iris root, midway along the radial length of the iris, and at the juxtapupillary margin were 0.4 ± 0.1, 0.5 ± 0.1, and 0.6 ± 0.1 mm, respectively. Those of the ciliary body, ciliary processes, and ciliary body + ciliary processes were 0.7 ± 0.1, 0.6 ± 0.1, and 1.3 ± 0.2 mm, respectively. This study provides standard, normative thickness data for the iris and ciliary body in healthy adults using ultrasonographic imaging. Copyright 2011, SLACK Incorporated.

Broadband infrared imaging spectroscopy for standoff detection of trace explosives

NASA Astrophysics Data System (ADS)

Kendziora, Christopher A.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; McGill, R. Andrew

2016-05-01

This manuscript describes advancements toward a mobile platform for standoff detection of trace explosives on relevant substrates using broadband infrared spectroscopic imaging. In conjunction with this, we are developing a technology for detection based on photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). PT-IRIS leverages one or more IR quantum cascade lasers (QCL), tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. Here we describe methods to increase both sensitivity to trace explosives and selectivity between different analyte types by exploiting a broader spectral range than in previous configurations. Previously we demonstrated PT-IRIS at several meters of standoff distance indoors and in field tests, while operating the lasers below the infrared eye-safe intensity limit (100 mW/cm2). Sensitivity to explosive traces as small as a single 10 μm diameter particle (~1 ng) has been demonstrated.

Wavelet Types Comparison for Extracting Iris Feature Based on Energy Compaction

NASA Astrophysics Data System (ADS)

Rizal Isnanto, R.

2015-06-01

Human iris has a very unique pattern which is possible to be used as a biometric recognition. To identify texture in an image, texture analysis method can be used. One of method is wavelet that extract the image feature based on energy. Wavelet transforms used are Haar, Daubechies, Coiflets, Symlets, and Biorthogonal. In the research, iris recognition based on five mentioned wavelets was done and then comparison analysis was conducted for which some conclusions taken. Some steps have to be done in the research. First, the iris image is segmented from eye image then enhanced with histogram equalization. The features obtained is energy value. The next step is recognition using normalized Euclidean distance. Comparison analysis is done based on recognition rate percentage with two samples stored in database for reference images. After finding the recognition rate, some tests are conducted using Energy Compaction for all five types of wavelets above. As the result, the highest recognition rate is achieved using Haar, whereas for coefficients cutting for C(i) < 0.1, Haar wavelet has a highest percentage, therefore the retention rate or significan coefficient retained for Haaris lower than other wavelet types (db5, coif3, sym4, and bior2.4)

Modeling IrisCode and its variants as convex polyhedral cones and its security implications.

PubMed

Kong, Adams Wai-Kin

2013-03-01

IrisCode, developed by Daugman, in 1993, is the most influential iris recognition algorithm. A thorough understanding of IrisCode is essential, because over 100 million persons have been enrolled by this algorithm and many biometric personal identification and template protection methods have been developed based on IrisCode. This paper indicates that a template produced by IrisCode or its variants is a convex polyhedral cone in a hyperspace. Its central ray, being a rough representation of the original biometric signal, can be computed by a simple algorithm, which can often be implemented in one Matlab command line. The central ray is an expected ray and also an optimal ray of an objective function on a group of distributions. This algorithm is derived from geometric properties of a convex polyhedral cone but does not rely on any prior knowledge (e.g., iris images). The experimental results show that biometric templates, including iris and palmprint templates, produced by different recognition methods can be matched through the central rays in their convex polyhedral cones and that templates protected by a method extended from IrisCode can be broken into. These experimental results indicate that, without a thorough security analysis, convex polyhedral cone templates cannot be assumed secure. Additionally, the simplicity of the algorithm implies that even junior hackers without knowledge of advanced image processing and biometric databases can still break into protected templates and reveal relationships among templates produced by different recognition methods.

Losing focus: how lens position and viewing angle affect the function of multifocal lenses in fishes.

PubMed

Gagnon, Yakir Luc; Wilby, David; Temple, Shelby Eric

2016-09-01

Light rays of different wavelengths are focused at different distances when they pass through a lens (longitudinal chromatic aberration [LCA]). For animals with color vision this can pose a serious problem, because in order to perceive a sharp image the rays must be focused at the shallow plane of the photoreceptor's outer segments in the retina. A variety of fish and tetrapods have been found to possess multifocal lenses, which correct for LCA by assigning concentric zones to correctly focus specific wavelengths. Each zone receives light from a specific beam entrance position (BEP) (the lateral distance between incoming light and the center of the lens). Any occlusion of incoming light at specific BEPs changes the composition of the wavelengths that are correctly focused on the retina. Here, we calculated the effect of lens position relative to the plane of the iris and light entering the eye at oblique angles on how much of the lens was involved in focusing the image on the retina (measured as the availability of BEPs). We used rotational photography of fish eyes and mathematical modeling to quantify the degree of lens occlusion. We found that, at most lens positions and viewing angles, there was a decrease of BEP availability and in some cases complete absence of some BEPs. Given the implications of these effects on image quality, we postulate that three morphological features (aphakic spaces, curvature of the iris, and intraretinal variability in spectral sensitivity) may, in part, be adaptations to mitigate the loss of spectral image quality in the periphery of the eyes of fishes.

Improved Iris Recognition through Fusion of Hamming Distance and Fragile Bit Distance.

PubMed

Hollingsworth, Karen P; Bowyer, Kevin W; Flynn, Patrick J

2011-12-01

The most common iris biometric algorithm represents the texture of an iris using a binary iris code. Not all bits in an iris code are equally consistent. A bit is deemed fragile if its value changes across iris codes created from different images of the same iris. Previous research has shown that iris recognition performance can be improved by masking these fragile bits. Rather than ignoring fragile bits completely, we consider what beneficial information can be obtained from the fragile bits. We find that the locations of fragile bits tend to be consistent across different iris codes of the same eye. We present a metric, called the fragile bit distance, which quantitatively measures the coincidence of the fragile bit patterns in two iris codes. We find that score fusion of fragile bit distance and Hamming distance works better for recognition than Hamming distance alone. To our knowledge, this is the first and only work to use the coincidence of fragile bit locations to improve the accuracy of matches.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos-Villalobos, Hector J; Barstow, Del R; Karakaya, Mahmut

Iris recognition has been proven to be an accurate and reliable biometric. However, the recognition of non-ideal iris images such as off angle images is still an unsolved problem. We propose a new biometric targeted eye model and a method to reconstruct the off-axis eye to its frontal view allowing for recognition using existing methods and algorithms. This allows for existing enterprise level algorithms and approaches to be largely unmodified by using our work as a pre-processor to improve performance. In addition, we describe the `Limbus effect' and its importance for an accurate segmentation of off-axis irides. Our method usesmore » an anatomically accurate human eye model and ray-tracing techniques to compute a transformation function, which reconstructs the iris to its frontal, non-refracted state. Then, the same eye model is used to render a frontal view of the reconstructed iris. The proposed method is fully described and results from synthetic data are shown to establish an upper limit on performance improvement and establish the importance of the proposed approach over traditional linear elliptical unwrapping methods. Our results with synthetic data demonstrate the ability to perform an accurate iris recognition with an image taken as much as 70 degrees off-axis.« less

2014 Summer Series - Robert Carvalho - Pursuing the Mysteries of the Sun: The IRIS Mission

NASA Image and Video Library

2014-06-19

Pursuing the Mysteries of the Sun: The Interface Region Imaging Spectrograph (IRIS) Mission. Flight controllers from the IRIS mission will present their individual experiences on IRIS from development through the first year of flight. This will begin with a discussion of the unique nature of IRIS's mission and science, and how it fits into NASA's fleet of solar observatories. Next will be a discussion of the critical roles Ames contributed in the mission including spacecraft and flight software development, ground system development, and training for launch. This will be followed by experiences from launch, early operations, ongoing operations, and unusual operations experiences. The presentation will close with IRIS science imagery and questions.

An Improved Iris Recognition Algorithm Based on Hybrid Feature and ELM

NASA Astrophysics Data System (ADS)

Wang, Juan

2018-03-01

The iris image is easily polluted by noise and uneven light. This paper proposed an improved extreme learning machine (ELM) based iris recognition algorithm with hybrid feature. 2D-Gabor filters and GLCM is employed to generate a multi-granularity hybrid feature vector. 2D-Gabor filter and GLCM feature work for capturing low-intermediate frequency and high frequency texture information, respectively. Finally, we utilize extreme learning machine for iris recognition. Experimental results reveal our proposed ELM based multi-granularity iris recognition algorithm (ELM-MGIR) has higher accuracy of 99.86%, and lower EER of 0.12% under the premise of real-time performance. The proposed ELM-MGIR algorithm outperforms other mainstream iris recognition algorithms.

The Prototype HyspIRI Thermal Infrared Radiometer (PHyTIR): A High Speed, Multispectral, Thermal Instrument Development in Support of HyspIRI-TIR

NASA Technical Reports Server (NTRS)

Hook, Simon

2011-01-01

The Prototype HyspIRI Thermal Infrared Radiometer (PHyTIR) is being developed as part of the risk reduction activities associated with the Hyperspectral Infrared Imager (HyspIRI). The HyspIRI mission was recommended by the National Research Council Decadal Survey and includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. The HyspIRI TIR system will have 60m ground resolution, better than 200mK noise equivalent delta temperature (NEDT), 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. PHyTIR addresses the technology readiness level (TRL) of certain key subsystems of the TIR imager, primarily the detector assembly and scanning mechanism. PHyTIR will use Mercury Cadmium Telluride (MCT) technology at the focal plane and operate in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence allowing the high data rates needed for the 5 day repeat. PHyTIR will also demonstrate a newly developed interferometeric metrology system. This system will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing post-processing (e.g. geo-rectification computations).

The best bits in an iris code.

PubMed

Hollingsworth, Karen P; Bowyer, Kevin W; Flynn, Patrick J

2009-06-01

Iris biometric systems apply filters to iris images to extract information about iris texture. Daugman's approach maps the filter output to a binary iris code. The fractional Hamming distance between two iris codes is computed and decisions about the identity of a person are based on the computed distance. The fractional Hamming distance weights all bits in an iris code equally. However, not all the bits in an iris code are equally useful. Our research is the first to present experiments documenting that some bits are more consistent than others. Different regions of the iris are compared to evaluate their relative consistency, and contrary to some previous research, we find that the middle bands of the iris are more consistent than the inner bands. The inconsistent-bit phenomenon is evident across genders and different filter types. Possible causes of inconsistencies, such as segmentation, alignment issues, and different filters are investigated. The inconsistencies are largely due to the coarse quantization of the phase response. Masking iris code bits corresponding to complex filter responses near the axes of the complex plane improves the separation between the match and nonmatch Hamming distance distributions.

HypsIRI On-Board Science Data Processing

NASA Technical Reports Server (NTRS)

Flatley, Tom

2010-01-01

Topics include On-board science data processing, on-board image processing, software upset mitigation, on-board data reduction, on-board 'VSWIR" products, HyspIRI demonstration testbed, and processor comparison.

KSC-2012-5883

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians install the wing on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-1784

NASA Image and Video Library

2013-03-05

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the three stages of the Orbital Sciences Corp. Pegasus XL rocket have been mated in preparation for the launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than April 29, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-2728

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences launch team monitors the Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit as the rocket and payload are moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2012-5878

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians prepare to install the wing on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-1785

NASA Image and Video Library

2013-03-05

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the three stages of the Orbital Sciences Corp. Pegasus XL rocket have been mated in preparation for the launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than April 29, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2012-5881

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians install the wing on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2012-5884

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians install the wing on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2012-5887

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians install the aft skirt on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-2725

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences launch team monitors the Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit as the rocket and payload are moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2483

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. - A mission logo decal for the launch of NASA's IRIS solar observatory aboard an Orbital Sciences Pegasus XL rocket. The decal is on the side of the Pegasus. Engineers are working inside a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2012-5885

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, a technician helps install the wing on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2012-5886

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians install the wing on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-1786

NASA Image and Video Library

2013-03-06

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the three stages of the Orbital Sciences Corp. Pegasus XL rocket have been mated in preparation for the launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than April 29, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2012-5889

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians install the aft skirt on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-2484

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. - A mission logo decal for the launch of NASA's IRIS solar observatory aboard an Orbital Sciences Pegasus XL rocket. The decal is on the side of the Pegasus. Engineers are working inside a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2729

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences launch team monitors the Pegasus XL rocket that will lift NASA's IRIS solar observatory into orbit as the rocket and payload are moved from a hangar onto a transporter at Vandenberg Air Force Base. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2012-5890

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians install the aft skirt on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2012-5879

NASA Image and Video Library

2012-10-09

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, technicians prepare to install the wing on the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-2203

NASA Image and Video Library

2013-04-25

VANDENBERG AIR FORCE BASE, Calif. -- The Interface Region Imaging Spectrograph, or IRIS, is being readied for mating to the Orbital Sciences Corp. Pegasus XL rocket that will launch the spacecraft. IRIS will be covered in a fairing after it's connected to the nose of the Pegasus to protect the spacecraft from atmospheric heating and stress during launch. Upcoming work includes electrical verification testing. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

Evaluation of Laser Stabilization and Imaging Systems for LCLS-II - Final Paper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barry, Matthew

2015-08-20

By combining the top performing commercial laser beam stabilization system with the most ideal optical imaging configuration, the beamline for the Linear Accelerator Coherent Light Source II (LCLS-II) will deliver the highest quality and most stable beam to the cathode. To determine the optimal combination, LCLS-II beamline conditions were replicated and the systems tested with a He-Ne laser. The Guidestar-II and MRC active laser beam stabilization systems were evaluated for their ideal positioning and stability. Both a two and four lens optical imaging configuration was then evaluated for beam imaging quality, magnification properties, and natural stability. In their best performancesmore » when tested over fifteen hours, Guidestar-II kept the beam stable over approximately 70-110um while the MRC system kept it stable over approximately 90-100um. During short periods of time, Guidestar-II kept the beam stable between 10-20um, but was more susceptible to drift over time, while the MRC system maintained the beam between 30-50um with less overall drift. The best optical imaging configuration proved to be a four lens system that images to the iris located in the cathode room and from there, imaged to the cathode. The magnification from the iris to the cathode was 2:1, within an acceptable tolerance to the expected 2.1:1 magnification. The two lens configuration was slightly more stable in small periods of time (less than 10 minutes) without the assistance of a stability system, approximately 55um compared to approximately 70um, but the four lens configurations beam image had a significantly flatter intensity distribution compared to the two lens configuration which had a Gaussian distribution. A final test still needs to be run with both stability systems running at the same time through the four lens system. With this data, the optimal laser beam stabilization system can be determined for the beamline of LCLS-II.« less

Physician acceptance of the IRIS user interface during a clinical trial at the Ottawa Civic Hospital

NASA Astrophysics Data System (ADS)

Coristine, Marjorie; Beeton, Carolyn; Tombaugh, Jo W.; Ahuja, J.; Belanger, Garry; Dillon, Richard F.; Currie, Shawn; Hind, E.

1990-07-01

During a clinical trial, emergency physicians and radiologists at the Ottawa Civic Hospital used IRIS (Integrated Radiological Information System) to process patients' x-rays, requisitions, and reports, and to have consultations, for 319 active cases. This paper discusses IRIS user interface issues raised during the clinical trial. The IRIS workstation consists of three major system components: 1) an image screen for viewing and enhancing images; 2) a control screen for presenting patient information, selecting images, and executing commands; and 3) a hands-free telephone for reporting activities and consultations. The control screen and hands-free telephone user interface allow physicians to navigate through patient files, select images and access reports, enter new reports, and perform remote consultations. Physicians were observed using the system during the trial and responded to questions about the user interface on an extensive debriefing interview after the trial. Overall, radiologists and emergency physicians were satisfied with IRIS control screen functionality and user interface. In a number of areas radiologists and emergency physicians differed in their user interface needs. Some features were found to be acceptable to one group of physicians but required modification to meet the needs of the other physician group. The data from the interviews, along with the comments from radiologists and emergency physicians provided important information for the revision of some features, and for the evolution of new features.

KSC-2013-2739

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The launch crew of the Orbital Sciences L-1011 aircraft called "Stargazer" after arrival at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2745

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences L-1011 aircraft called "Stargazer" arrives at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2740

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The launch crew of the Orbital Sciences L-1011 aircraft called "Stargazer" after arrival at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2738

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The launch crew of the Orbital Sciences L-1011 aircraft called "Stargazer" after arrival at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2743

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences L-1011 aircraft called "Stargazer" arrives at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2736

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The cockpit of the Orbital Sciences L-1011 aircraft called "Stargazer" after arrival at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2744

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. – One of the portable control trailers is set up at Vandenberg Air Force Base for the upcoming launch of an Orbital Sciences Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2735

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The Orbital Sciences L-1011 aircraft called "Stargazer" arrives at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2737

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. - The launch crew of the Orbital Sciences L-1011 aircraft called "Stargazer" after arrival at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

Extending the Capture Volume of an Iris Recognition System Using Wavefront Coding and Super-Resolution.

PubMed

Hsieh, Sheng-Hsun; Li, Yung-Hui; Tien, Chung-Hao; Chang, Chin-Chen

2016-12-01

Iris recognition has gained increasing popularity over the last few decades; however, the stand-off distance in a conventional iris recognition system is too short, which limits its application. In this paper, we propose a novel hardware-software hybrid method to increase the stand-off distance in an iris recognition system. When designing the system hardware, we use an optimized wavefront coding technique to extend the depth of field. To compensate for the blurring of the image caused by wavefront coding, on the software side, the proposed system uses a local patch-based super-resolution method to restore the blurred image to its clear version. The collaborative effect of the new hardware design and software post-processing showed great potential in our experiment. The experimental results showed that such improvement cannot be achieved by using a hardware-or software-only design. The proposed system can increase the capture volume of a conventional iris recognition system by three times and maintain the system's high recognition rate.

In vivo analysis of the iris thickness by spectral domain optical coherence tomography.

PubMed

Invernizzi, Alessandro; Cigada, Mario; Savoldi, Luisa; Cavuto, Silvio; Fontana, Luigi; Cimino, Luca

2014-09-01

To assess the effectiveness of spectral domain optical coherence tomography (SD-OCT) in providing in vivo measurements of iris thickness in healthy and pathological subjects. 14 healthy volunteers and 14 patients with unilateral Fuchs' uveitis were enrolled in the study. The two groups were comparable for age, gender and race. Each subject underwent complete clinical examination and anterior segment SD-OCT imaging in both eyes. SD-OCT scans of the iris were performed following a cross-sectional pattern. Iris thickness values were obtained using a purposely developed software-based analysis of OCT images. Measurements were carried out twice by two trained independent operators to assess intraobserver and interobserver repeatability. Analysis of iris thickness was conducted in four main quadrants: superior, inferior, nasal and temporal. Iris thickness values from normal subjects were compared with the ones measured in the affected and fellow eyes of patients with Fuchs' uveitis. Iris thickness measurements showed good intraobserver and interobserver repeatability (intraclass correlation coefficient >0.971). Superior and temporal iris sectors showed respectively thickest and thinnest values in all groups. In healthy eyes, iris thickness ranged from 327.92±37.29 μm temporally to 405.25±48.49 μm superiorly. Iris thickness measurements in the affected eyes of Fuchs' uveitis patients ranged from 285.48±56.02 μm temporally to 376.12±60.97 μm superiorly. Multiple comparison analysis showed iris thickness values to be significantly lower in eyes affected by Fuchs' uveitis than both in fellow eyes (p<0.001) of the same patients and in healthy eyes (p=0.0074). SD-OCT is a suitable technique for iris thickness assessment. Thickness analysis must be carried out using a sectorial approach, taking into consideration anatomical variations existing between different iris regions. SD-OCT is a potentially useful tool for detecting iris thickness variations induced by pathological conditions such as Fuchs' uveitis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Relationship between iris surface features and angle width in Asian eyes.

PubMed

Sidhartha, Elizabeth; Nongpiur, Monisha Esther; Cheung, Carol Y; He, Mingguang; Wong, Tien Yin; Aung, Tin; Cheng, Ching-Yu

2014-10-23

To examine the associations between iris surface features with anterior chamber angle width in Asian eyes. In this prospective cross-sectional study, we recruited 600 subjects from a large population-based study, the Singapore Epidemiology of Eye Diseases (SEED) study. We obtained standardized digital slit-lamp iris photographs and graded the iris crypts (by number and size), furrows (by number and circumferential extent), and color (higher grade denoting darker iris). Vertical and horizontal cross-sections of anterior chamber were imaged using anterior segment optical coherence tomography. Angle opening distance (AOD), angle recess area (ARA), and trabecular-iris space area (TISA) were measured using customized software. Associations of the angle width with the iris surface features in the subject's right eyes were assessed using linear regression analysis. A total of 464 eyes of the 464 subjects (mean age: 57.5 ± 8.6 years) had complete and gradable data for crypts and color, and 423 eyes had gradable data for furrows. After adjustment for age, sex, ethnicity, pupil size, and corneal arcus, higher crypt grade was independently associated with wider AOD750 (β [change in angle width per grade higher] = 0.018, P = 0.023), ARA750 (β = 0.022, P = 0.049), and TISA750 (β = 0.011, P = 0.019), and darker iris was associated narrower ARA750 (β = -0.025, P = 0.044) and TISA750 (β = -0.013, P = 0.011). Iris surface features, assessed and measured from slit-lamp photographs, correlated well with anterior chamber angle width; irises with more crypts and lighter color were associated with wider angle. These findings may provide another imaging modality to assess angle closure risk based on iris surface features. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Biometric analysis of pigment dispersion syndrome using anterior segment optical coherence tomography.

PubMed

Aptel, Florent; Beccat, Sylvain; Fortoul, Vincent; Denis, Philippe

2011-08-01

To compare anterior chamber volume (ACV), iris volume, and iridolenticular contact (ILC) area before and after laser peripheral iridotomy (LPI) in eyes with pigment dispersion syndrome (PDS) using anterior segment optical coherence tomography (AS OCT) and image processing software. Cross-sectional study. Eighteen eyes of 18 patients with PDS; 30 eyes of 30 controls matched for age, gender, and refraction. Anterior segment OCT imaging was performed in all eyes before LPI and 1, 4, and 12 weeks after LPI. At each visit, 12 cross-sectional images of the AS were taken: 4 in bright conditions with accommodation (accommodation), 4 in bright conditions without accommodation (physiological miosis), and 4 under dark conditions (physiologic mydriasis). Biometric parameters were estimated using AS OCT radial sections and customized image-processing software. Anterior chamber volume, iris volume-to-length ratio, ILC area, AS OCT anterior chamber depth, and A-scan ultrasonography axial length. Before LPI, PDS eyes had a significantly greater ACV and ILC area than control eyes (P<0.01) and a significantly smaller iris volume-to-length ratio than the controls (P<0.05). After LPI, ACV and ILC area decreased significantly in PDS eyes, but iris volume-to-length ratio increased significantly (P<0.02) and was not significantly different from that of controls. These biometric changes were stable over time. Iris volume-to-length ratio decreased significantly from accommodation to mydriasis and from miosis to mydriasis, both in PDS and control eyes (P<0.01). In PDS eyes, ILC area decreased significantly from accommodation to mydriasis, both before and after LPI (P<0.01). On multivariate analysis, greater anterior chamber (AC) volume (P<0.02) and larger AC depth (P<0.05) before LPI were significant predictors of a larger ILC area. Pigment dispersion syndrome eyes do not have an iris that is abnormally large, relative to the AS size, but have a weakly resistant iris that is stretched and pushed against the lens when there is a pressure difference across the iris. The author(s) have no proprietary or commercial interest in any materials discussed in this article. Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Comparison of Hyperspectral and Multispectral Satellites for Forest Alliance Classification in the San Francisco Bay Area

NASA Astrophysics Data System (ADS)

Clark, M. L.

2016-12-01

The goal of this study was to assess multi-temporal, Hyperspectral Infrared Imager (HyspIRI) satellite imagery for improved forest class mapping relative to multispectral satellites. The study area was the western San Francisco Bay Area, California and forest alliances (e.g., forest communities defined by dominant or co-dominant trees) were defined using the U.S. National Vegetation Classification System. Simulated 30-m HyspIRI, Landsat 8 and Sentinel-2 imagery were processed from image data acquired by NASA's AVIRIS airborne sensor in year 2015, with summer and multi-temporal (spring, summer, fall) data analyzed separately. HyspIRI reflectance was used to generate a suite of hyperspectral metrics that targeted key spectral features related to chemical and structural properties. The Random Forests classifier was applied to the simulated images and overall accuracies (OA) were compared to those from real Landsat 8 images. For each image group, broad land cover (e.g., Needle-leaf Trees, Broad-leaf Trees, Annual agriculture, Herbaceous, Built-up) was classified first, followed by a finer-detail forest alliance classification for pixels mapped as closed-canopy forest. There were 5 needle-leaf tree alliances and 16 broad-leaf tree alliances, including 7 Quercus (oak) alliance types. No forest alliance classification exceeded 50% OA, indicating that there was broad spectral similarity among alliances, most of which were not spectrally pure but rather a mix of tree species. In general, needle-leaf (Pine, Redwood, Douglas Fir) alliances had better class accuracies than broad-leaf alliances (Oaks, Madrone, Bay Laurel, Buckeye, etc). Multi-temporal data classifications all had 5-6% greater OA than with comparable summer data. For simulated data, HyspIRI metrics had 4-5% greater OA than Landsat 8 and Sentinel-2 multispectral imagery and 3-4% greater OA than HyspIRI reflectance. Finally, HyspIRI metrics had 8% greater OA than real Landsat 8 imagery. In conclusion, forest alliance classification was found to be a difficult remote sensing application with moderate resolution (30 m) satellite imagery; however, of the data tested, HyspIRI spectral metrics had the best performance relative to multispectral satellites.

Iris unwrapping using the Bresenham circle algorithm for real-time iris recognition

NASA Astrophysics Data System (ADS)

Carothers, Matthew T.; Ngo, Hau T.; Rakvic, Ryan N.; Broussard, Randy P.

2015-02-01

An efficient parallel architecture design for the iris unwrapping process in a real-time iris recognition system using the Bresenham Circle Algorithm is presented in this paper. Based on the characteristics of the model parameters this algorithm was chosen over the widely used polar conversion technique as the iris unwrapping model. The architecture design is parallelized to increase the throughput of the system and is suitable for processing an inputted image size of 320 × 240 pixels in real-time using Field Programmable Gate Array (FPGA) technology. Quartus software is used to implement, verify, and analyze the design's performance using the VHSIC Hardware Description Language. The system's predicted processing time is faster than the modern iris unwrapping technique used today∗.

IRIS Mission Operations Director's Colloquium

NASA Technical Reports Server (NTRS)

Carvalho, Robert; Mazmanian, Edward A.

2014-01-01

Pursuing the Mysteries of the Sun: The Interface Region Imaging Spectrograph (IRIS) Mission. Flight controllers from the IRIS mission will present their individual experiences on IRIS from development through the first year of flight. This will begin with a discussion of the unique nature of IRISs mission and science, and how it fits into NASA's fleet of solar observatories. Next will be a discussion of the critical roles Ames contributed in the mission including spacecraft and flight software development, ground system development, and training for launch. This will be followed by experiences from launch, early operations, ongoing operations, and unusual operations experiences. The presentation will close with IRIS science imagery and questions.

Multispectral iris recognition based on group selection and game theory

NASA Astrophysics Data System (ADS)

Ahmad, Foysal; Roy, Kaushik

2017-05-01

A commercially available iris recognition system uses only a narrow band of the near infrared spectrum (700-900 nm) while iris images captured in the wide range of 405 nm to 1550 nm offer potential benefits to enhance recognition performance of an iris biometric system. The novelty of this research is that a group selection algorithm based on coalition game theory is explored to select the best patch subsets. In this algorithm, patches are divided into several groups based on their maximum contribution in different groups. Shapley values are used to evaluate the contribution of patches in different groups. Results show that this group selection based iris recognition

KSC-2013-2643

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – The Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June is seen after the payload fairing was connected over NASA's IRIS spacecraft. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2494

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers unwrap NASA's IRIS spacecraft after its connection to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2012-5601

NASA Image and Video Library

2012-09-25

Vandenberg Air Force Base, Calif. – At Vandenberg Air Force Base in California, technicians install the avionics shelf on the third stage of the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

KSC-2013-2493

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers unwrap NASA's IRIS spacecraft after its connection to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2012-5602

NASA Image and Video Library

2012-09-25

Vandenberg Air Force Base, Calif. – At Vandenberg Air Force Base in California, technicians install the avionics shelf on the third stage of the Orbital Sciences Corp. Pegasus XL rocket which will launch the Interface Region Imaging Spectrograph, or IRIS, spacecraft. Scheduled for launch from Vandenberg Air Force Base no earlier than Feb. 27, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. For more information, visit http://iris.gsfc.nasa.gov Photo credit: NASA/Randy Beaudoin

Transition-Region Ultraviolet Explosive Events in IRIS Si IV: A Statistical Analysis

NASA Astrophysics Data System (ADS)

Bartz, Allison

2018-01-01

Explosive events (EEs) in the solar transition region are characterized by broad, non-Gaussian line profiles with wings at Doppler velocities exceeding the speed of sound. We present a statistical analysis of 23 IRIS (Interface Region Imaging Spectrograph) sit-and-stare observations, observed between April 2014 and March 2017. Using the IRIS Si IV 1394 Å and 1403 Å spectral windows and the 1400Å Slit Jaw images we have identified 581 EEs. We found that most EEs last less than 20 min. and have a spatial scale on the slit less than 10”, agreeing with measurements in previous work. We observed most EEs in active regions, regardless of date of observation, but selection bias of IRIS observations cannot be ruled out. We also present preliminary findings of optical depth effects from our statistical study.

Infrared instrument support for HyspIRI-TIR

NASA Astrophysics Data System (ADS)

Johnson, William R.; Hook, Simon J.; Foote, Marc; Eng, Bjorn T.; Jau, Bruno

2012-10-01

The Jet Propulsion Laboratory is currently developing an end-to-end instrument which will provide a proof of concept prototype vehicle for a high data rate, multi-channel, thermal instrument in support of the Hyperspectral Infrared Imager (HyspIRI)-Thermal Infrared (TIR) space mission. HyspIRI mission was recommended by the National Research Council Decadal Survey (DS). The HyspIRI mission includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. The prototype testbed instrument addressed in this effort will only support the TIR. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. Current designs for the HyspIRI-TIR space borne imager utilize eight spectral bands delineated with filters. The system will have 60m ground resolution, 200mK NEDT, 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. The prototype instrument will use mercury cadmium telluride (MCT) technology at the focal plane array in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence high data rates needed for the 5 day repeat. The current HyspIRI requirements dictate a ground knowledge measurement of 30m, so the prototype instrument will tackle this problem with a newly developed interferometeric metrology system. This will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing post-processing (e.g. geo-rectification computations).

High speed, multi-channel, thermal instrument development in support of HyspIRI-TIR

NASA Astrophysics Data System (ADS)

Johnson, William R.; Hook, Simon J.; Foote, Marc; Eng, Bjorn T.; Jau, Bruno

2011-10-01

The Jet Propulsion Laboratory is currently developing an end-to-end instrument which will provide a proof of concept prototype vehicle for a high data rate, multi-channel, thermal instrument in support of the Hyperspectral Infrared Imager (HyspIRI)-Thermal Infrared (TIR) space mission. HyspIRI mission was recommended by the National Research Council Decadal Survey (DS). The HyspIRI mission includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. The prototype testbed instrument addressed in this effort will only support the TIR. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. Current designs for the HyspIRI-TIR space borne imager utilize eight spectral bands delineated with filters. The system will have 60m ground resolution, 200mK NEDT, 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. The prototype instrument will use mercury cadmium telluride (MCT) technology at the focal plane array in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence high data rates needed for the 5 day repeat. The current HyspIRI requirements dictate a ground knowledge measurement of 30m, so the prototype instrument will tackle this problem with a newly developed interferometeric metrology system. This will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing postprocessing (e.g. geo-rectification computations).

Joint functional impairment and thermal alterations in patients with Psoriatic Arthritis: A thermal imaging study.

PubMed

Capo, A; Ismail, E; Cardone, D; Celletti, E; Auriemma, M; Sabatini, E; Merla, A; Amerio, P

2015-11-01

Functional infrared imaging (fIRI) is used to provide information on circulation, thermal properties and thermoregulatory function of the cutaneous tissue in several clinical settings. This study aims to evaluate the application of fIRI in Psoriatic Arthritis (PsA) assessment, evaluating the thermoregulatory alterations due to joint inflammation in PsA patients both in basal conditions and after a mild functional (isometric) exercise; fIRI outcomes were compared with those provided by Power Doppler Ultrasonography (PWD-US). 10 patients with PsA and 11 healthy controls were enrolled in the study. The cutaneous temperature dynamics of 20 regions of interest located on the dominant hand were recorded by means of high-resolution thermal imaging at baseline and after a functional exercise. Higher temperature values and faster temperature variations characterized the PsA group compared to healthy controls, confirming that the PsA-related inflammatory state alters the normal thermal proprieties of the skin overlying inflamed joints. fIRI outcomes correlated with the PWD-US findings. fIRI applied to the study of the response to a functional stimulus may represent an innovative, non-invasive, and operator-independent method for the assessment of peripheral PsA. Copyright © 2015 Elsevier Inc. All rights reserved.

Noninvasive monitoring of Pirenoxine Sodium concentration in aqueous humor based on dual-wavelength iris imaging technique

PubMed Central

Zhou, Yong; Hu, Ye; Zeng, Nan; Ji, Yanhong; Dai, Xiangsong; Li, Peng; Ma, Hui; He, Yonghong

2011-01-01

We present a noninvasive method of detecting substance concentration in the aqueous humor based on dual-wavelength iris imaging technology. Two light sources, one centered within (392 nm) and the other centered outside (850 nm) of an absorption band of Pirenoxine Sodium, a common type of drugs in eye disease treatment, were used for dual-wavelength iris imaging measurement. After passing through the aqueous humor twice, the back-scattering light was detected by a charge-coupled device (CCD). The detected images were then used to calculate the concentration of Pirenoxine Sodium. In eye model experiment, a resolution of 0.6525 ppm was achieved. Meanwhile, at least 4 ppm can be distinguished in in vivo experiment. These results demonstrated that our method can measure Pirenoxine Sodium concentration in the aqueous humor and its potential ability to monitor other materials’ concentration in the aqueous humor. PMID:21339869

Comparing an FPGA to a Cell for an Image Processing Application

NASA Astrophysics Data System (ADS)

Rakvic, Ryan N.; Ngo, Hau; Broussard, Randy P.; Ives, Robert W.

2010-12-01

Modern advancements in configurable hardware, most notably Field-Programmable Gate Arrays (FPGAs), have provided an exciting opportunity to discover the parallel nature of modern image processing algorithms. On the other hand, PlayStation3 (PS3) game consoles contain a multicore heterogeneous processor known as the Cell, which is designed to perform complex image processing algorithms at a high performance. In this research project, our aim is to study the differences in performance of a modern image processing algorithm on these two hardware platforms. In particular, Iris Recognition Systems have recently become an attractive identification method because of their extremely high accuracy. Iris matching, a repeatedly executed portion of a modern iris recognition algorithm, is parallelized on an FPGA system and a Cell processor. We demonstrate a 2.5 times speedup of the parallelized algorithm on the FPGA system when compared to a Cell processor-based version.

IRIS COLOUR CLASSIFICATION SCALES – THEN AND NOW

PubMed Central

Grigore, Mariana; Avram, Alina

2015-01-01

Eye colour is one of the most obvious phenotypic traits of an individual. Since the first documented classification scale developed in 1843, there have been numerous attempts to classify the iris colour. In the past centuries, iris colour classification scales has had various colour categories and mostly relied on comparison of an individual’s eye with painted glass eyes. Once photography techniques were refined, standard iris photographs replaced painted eyes, but this did not solve the problem of painted/ printed colour variability in time. Early clinical scales were easy to use, but lacked objectivity and were not standardised or statistically tested for reproducibility. The era of automated iris colour classification systems came with the technological development. Spectrophotometry, digital analysis of high-resolution iris images, hyper spectral analysis of the human real iris and the dedicated iris colour analysis software, all accomplished an objective, accurate iris colour classification, but are quite expensive and limited in use to research environment. Iris colour classification systems evolved continuously due to their use in a wide range of studies, especially in the fields of anthropology, epidemiology and genetics. Despite the wide range of the existing scales, up until present there has been no generally accepted iris colour classification scale. PMID:27373112

IRIS COLOUR CLASSIFICATION SCALES--THEN AND NOW.

PubMed

Grigore, Mariana; Avram, Alina

2015-01-01

Eye colour is one of the most obvious phenotypic traits of an individual. Since the first documented classification scale developed in 1843, there have been numerous attempts to classify the iris colour. In the past centuries, iris colour classification scales has had various colour categories and mostly relied on comparison of an individual's eye with painted glass eyes. Once photography techniques were refined, standard iris photographs replaced painted eyes, but this did not solve the problem of painted/ printed colour variability in time. Early clinical scales were easy to use, but lacked objectivity and were not standardised or statistically tested for reproducibility. The era of automated iris colour classification systems came with the technological development. Spectrophotometry, digital analysis of high-resolution iris images, hyper spectral analysis of the human real iris and the dedicated iris colour analysis software, all accomplished an objective, accurate iris colour classification, but are quite expensive and limited in use to research environment. Iris colour classification systems evolved continuously due to their use in a wide range of studies, especially in the fields of anthropology, epidemiology and genetics. Despite the wide range of the existing scales, up until present there has been no generally accepted iris colour classification scale.

An inverse method to determine the mechanical properties of the iris in vivo

PubMed Central

2014-01-01

Background Understanding the mechanical properties of the iris can help to have an insight into the eye diseases with abnormalities of the iris morphology. Material parameters of the iris were simply calculated relying on the ex vivo experiment. However, the mechanical response of the iris in vivo is different from that ex vivo, therefore, a method was put forward to determine the material parameters of the iris using the optimization method in combination with the finite element method based on the in vivo experiment. Material and methods Ocular hypertension was induced by rapid perfusion to the anterior chamber, during perfusion intraocular pressures in the anterior and posterior chamber were record by sensors, images of the anterior segment were captured by the ultrasonic system. The displacement of the characteristic points on the surface of the iris was calculated. A finite element model of the anterior chamber was developed using the ultrasonic image before perfusion, the multi-island genetic algorithm was employed to determine the material parameters of the iris by minimizing the difference between the finite element simulation and the experimental measurements. Results Material parameters of the iris in vivo were identified as the iris was taken as a nearly incompressible second-order Ogden solid. Values of the parameters μ1, α1, μ2 and α2 were 0.0861 ± 0.0080 MPa, 54.2546 ± 12.7180, 0.0754 ± 0.0200 MPa, and 48.0716 ± 15.7796 respectively. The stability of the inverse finite element method was verified, the sensitivity of the model parameters was investigated. Conclusion Material properties of the iris in vivo could be determined using the multi-island genetic algorithm coupled with the finite element method based on the experiment. PMID:24886660

KSC-2013-2485

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. - An Orbital Sciences Pegasus XL rocket undergoes launch preparations inside a hangar at Vandenberg Air Force Base for NASA's IRIS mission, short for Interface Region Imaging Spectrograph. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2486

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. - An Orbital Sciences Pegasus XL rocket undergoes launch preparations inside a hangar at Vandenberg Air Force Base for NASA's IRIS mission, short for Interface Region Imaging Spectrograph. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

Increasing the information acquisition volume in iris recognition systems.

PubMed

Barwick, D Shane

2008-09-10

A significant hurdle for the widespread adoption of iris recognition in security applications is that the typically small imaging volume for eye placement results in systems that are not user friendly. Separable cubic phase plates at the lens pupil have been shown to ameliorate this disadvantage by increasing the depth of field. However, these phase masks have limitations on how efficiently they can capture the information-bearing spatial frequencies in iris images. The performance gains in information acquisition that can be achieved by more general, nonseparable phase masks is demonstrated. A detailed design method is presented, and simulations using representative designs allow for performance comparisons.

Challenges in diagnosis and management of Cryptococcal immune reconstitution inflammatory syndrome (IRIS) in resource limited settings.

PubMed

Musubire, A K; Meya, B D; Mayanja-Kizza, H; Lukande, R; Wiesner, L D; Bohjanen, P; R Boulware, R D

2012-06-01

In many resource-limited settings, cryptococcal meningitis (CM) contributes up to 20% of all deaths with further complications due to Immune Reconstitution Inflammatory Syndrome (IRIS). We present a case report on a patient who developed CM-IRIS and then subsequent CM-relapse with a fluconazole-resistant organism and then later CM-IRIS once again, manifesting as cystic cryptococcomas, hydrocephalus, and sterile CSF. In this case we, demonstrate that CM-IRIS and persistent low level cryptococcal infection are not mutually exclusive phenomena. The management of IRIS with corticosteroids may increase the risk of culture positive CM-relapse which may further increase the risk of recurrent IRIS and resulting complications including death. We also highlight the role of imaging and fluconazole resistance testing in patients with recurrent meningitis and the importance of CSF cultures in guiding treatment decisions.

New methods in iris recognition.

PubMed

Daugman, John

2007-10-01

This paper presents the following four advances in iris recognition: 1) more disciplined methods for detecting and faithfully modeling the iris inner and outer boundaries with active contours, leading to more flexible embedded coordinate systems; 2) Fourier-based methods for solving problems in iris trigonometry and projective geometry, allowing off-axis gaze to be handled by detecting it and "rotating" the eye into orthographic perspective; 3) statistical inference methods for detecting and excluding eyelashes; and 4) exploration of score normalizations, depending on the amount of iris data that is available in images and the required scale of database search. Statistical results are presented based on 200 billion iris cross-comparisons that were generated from 632500 irises in the United Arab Emirates database to analyze the normalization issues raised in different regions of receiver operating characteristic curves.

Deep learning architecture for iris recognition based on optimal Gabor filters and deep belief network

NASA Astrophysics Data System (ADS)

He, Fei; Han, Ye; Wang, Han; Ji, Jinchao; Liu, Yuanning; Ma, Zhiqiang

2017-03-01

Gabor filters are widely utilized to detect iris texture information in several state-of-the-art iris recognition systems. However, the proper Gabor kernels and the generative pattern of iris Gabor features need to be predetermined in application. The traditional empirical Gabor filters and shallow iris encoding ways are incapable of dealing with such complex variations in iris imaging including illumination, aging, deformation, and device variations. Thereby, an adaptive Gabor filter selection strategy and deep learning architecture are presented. We first employ particle swarm optimization approach and its binary version to define a set of data-driven Gabor kernels for fitting the most informative filtering bands, and then capture complex pattern from the optimal Gabor filtered coefficients by a trained deep belief network. A succession of comparative experiments validate that our optimal Gabor filters may produce more distinctive Gabor coefficients and our iris deep representations be more robust and stable than traditional iris Gabor codes. Furthermore, the depth and scales of the deep learning architecture are also discussed.

Three-Dimensional Morphometric Analysis of the Iris by Swept-Source Anterior Segment Optical Coherence Tomography in a Caucasian Population.

PubMed

Invernizzi, Alessandro; Giardini, Piero; Cigada, Mario; Viola, Francesco; Staurenghi, Giovanni

2015-07-01

We analyzed by swept-source anterior segment optical coherence tomography (SS-ASOCT) the three-dimensional iris morphology in a Caucasian population, and correlated the findings with iris color, iris sectors, subject age, and sex. One eye each from consecutive healthy emmetropic (refractive spherical equivalent ± 3 diopters) volunteers were selected for the study. The enrolled eye underwent standardized anterior segment photography to assess iris color. Iris images were assessed by SS-ASOCT for volume, thickness, width, and pupil size. Sectoral variations of morphometric data among the superior, nasal, inferior, and temporal sectors were recorded. A total of 135 eyes from 57 males and 78 females, age 49 ± 17 years, fulfilled the inclusion criteria. All iris morphometric parameters varied significantly among the different sectors (all P < 0.0001). Iris total volume and thickness were significantly correlated with increasingly darker pigmentation (P < 0.0001, P = 0.0384, respectively). Neither width nor pupil diameter was influenced by iris color. Age did not affect iris volume or thickness; iris width increased and pupil diameter decreased with age (rs = 0.52, rs = -0.58, respectively). There was no effect of sex on iris volume, thickness, or pupil diameter; iris width was significantly greater in males (P = 0.007). Morphology of the iris varied by iris sector, and iris color was associated with differences in iris volume and thickness. Morphological parameter variations associated with iris color, sector, age, and sex can be used to identify pathological changes in suspect eyes. To be effective in clinical settings, construction of iris morphological databases for different ethnic and racial populations is essential.

Frontal view reconstruction for iris recognition

DOEpatents

Santos-Villalobos, Hector J; Bolme, David S; Boehnen, Chris Bensing

2015-02-17

Iris recognition can be accomplished for a wide variety of eye images by correcting input images with an off-angle gaze. A variety of techniques, from limbus modeling, corneal refraction modeling, optical flows, and genetic algorithms can be used. A variety of techniques, including aspherical eye modeling, corneal refraction modeling, ray tracing, and the like can be employed. Precomputed transforms can enhance performance for use in commercial applications. With application of the technologies, images with significantly unfavorable gaze angles can be successfully recognized.

Workshop to discuss NRC 2014 Recommendations for IRIS

EPA Pesticide Factsheets

EPA is holding a public workshop to discuss some specific recommendations from the National Academies' National Research Council's May 2014 report on further improving the scientific quality of IRIS assessments.

Feature Vector Construction Method for IRIS Recognition

NASA Astrophysics Data System (ADS)

Odinokikh, G.; Fartukov, A.; Korobkin, M.; Yoo, J.

2017-05-01

One of the basic stages of iris recognition pipeline is iris feature vector construction procedure. The procedure represents the extraction of iris texture information relevant to its subsequent comparison. Thorough investigation of feature vectors obtained from iris showed that not all the vector elements are equally relevant. There are two characteristics which determine the vector element utility: fragility and discriminability. Conventional iris feature extraction methods consider the concept of fragility as the feature vector instability without respect to the nature of such instability appearance. This work separates sources of the instability into natural and encodinginduced which helps deeply investigate each source of instability independently. According to the separation concept, a novel approach of iris feature vector construction is proposed. The approach consists of two steps: iris feature extraction using Gabor filtering with optimal parameters and quantization with separated preliminary optimized fragility thresholds. The proposed method has been tested on two different datasets of iris images captured under changing environmental conditions. The testing results show that the proposed method surpasses all the methods considered as a prior art by recognition accuracy on both datasets.

KSC-2013-2628

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2490

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers unwrap NASA's IRIS spacecraft after its connection to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg no earlier than June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2503

NASA Image and Video Library

2013-05-30

VANDENBERG AFB, Calif. – Engineers prepare to install a radial retraction system on NASA's IRIS spacecraft after its connection to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2601

NASA Image and Video Library

2013-06-10

VANDENBERG AFB, Calif. – Engineers conduct inspections on NASA's IRIS spacecraft with blacklights before the payload fairing before it is connected. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2642

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences team engineers monitor the connection of the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2640

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – The payload fairing locked in place over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2618

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences team members watch as engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2613

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Engineers attach the starboard side of the payload fairing into place for NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2581

NASA Image and Video Library

2013-06-05

VANDENBERG AFB – Engineers move the port side of the payload fairing before it is connected into place for NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2477

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers prepare to connect NASA's IRIS spacecraft to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg no earlier than June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2617

NASA Image and Video Library

2013-06-10

VANDENBERG AFB - Orbital Sciences engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2636

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2641

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences engineers monitor the connection of the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2619

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – NASA's IRIS spacecraft before the second half of the payload fairing is installed over it. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2480

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers prepare to connect NASA's IRIS spacecraft to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg no earlier than June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2635

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2481

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers prepare to connect NASA's IRIS spacecraft to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg no earlier than June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2633

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences team members move the second half of the payload fairing before it is placed over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2489

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers unwrap NASA's IRIS spacecraft after its connection to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg no earlier than June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2639

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2504

NASA Image and Video Library

2013-05-30

VANDENBERG AFB, Calif. – Engineers install a radial retraction system on NASA's IRIS spacecraft after its connection to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2637

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2630

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences team members move the second half of the payload fairing before it is placed over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2602

NASA Image and Video Library

2013-06-10

VANDENBERG AFB, Calif. – Engineers conduct inspections on NASA's IRIS spacecraft with blacklights before the payload fairing before it is connected. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2580

NASA Image and Video Library

2013-06-05

- VANDENBERG AFB – An engineer makes preparations on the starboard side of the payload fairing before it is connected into place for NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2626

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences team members move the second half of the payload fairing before it is placed over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2616

NASA Image and Video Library

2013-06-11

Orbital Sciences engineers connect the payload fairing over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2482

NASA Image and Video Library

2013-05-29

VANDENBERG AFB, Calif. – Engineers prepare to connect NASA's IRIS spacecraft to the nose of an Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg no earlier than June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Randy Beaudoin

KSC-2013-2629

NASA Image and Video Library

2013-06-10

VANDENBERG AFB – Orbital Sciences team members move the second half of the payload fairing before it is placed over NASA's IRIS spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit in June. The work is taking place in a hangar at Vandenberg Air Force Base where IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg June 26, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: NASA/Tony Vauclin

KSC-2013-2828

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2825

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2831

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2885

NASA Image and Video Library

2013-06-24

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, mission managers participate in a pre-launch dress rehearsal in the Launch Vehicle Data Center for NASA’s Interface Region Imaging Spectrograph, or IRIS, solar observatory. Scheduled for launch from Vandenberg on June 26 aboard an Orbital Sciences Pegasus XL rocket, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region in to the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun’s visible surface and upper atmosphere, is where most of the sun’s ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth’s climate. For more information, visit http://www.nasa.gov/iris. Photo credit: NASA/Daniel Casper

KSC-2013-2830

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2832

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2912

NASA Image and Video Library

2013-06-25

VANDENBERG AIR FORCE BASE, Calif. – Final checkouts are being completed at Vandenberg Air Force Base in California as preparations continue for the launch from the L-1011 carrier aircraft of the Orbital Sciences Corp. Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/ Daniel Casper

KSC-2013-2833

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2824

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2888

NASA Image and Video Library

2013-06-24

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, mission managers participate in a pre-launch dress rehearsal in the Launch Vehicle Data Center for NASA’s Interface Region Imaging Spectrograph, or IRIS, solar observatory. Scheduled for launch from Vandenberg on June 26 aboard an Orbital Sciences Pegasus XL rocket, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region in to the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun’s visible surface and upper atmosphere, is where most of the sun’s ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth’s climate. For more information, visit http://www.nasa.gov/iris. Photo credit: NASA/Daniel Casper

KSC-2013-2827

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2826

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2887

NASA Image and Video Library

2013-06-24

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, mission managers participate in a pre-launch dress rehearsal in the Launch Vehicle Data Center for NASA’s Interface Region Imaging Spectrograph, or IRIS, solar observatory. Scheduled for launch from Vandenberg on June 26 aboard an Orbital Sciences Pegasus XL rocket, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region in to the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun’s visible surface and upper atmosphere, is where most of the sun’s ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth’s climate. For more information, visit http://www.nasa.gov/iris. Photo credit: NASA/Daniel Casper

KSC-2013-2911

NASA Image and Video Library

2013-06-25

VANDENBERG AIR FORCE BASE, Calif. – Final checkouts are being completed at Vandenberg Air Force Base in California as preparations continue for the launch from the L-1011 carrier aircraft of the Orbital Sciences Corp. Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/ Daniel Casper

KSC-2013-2829

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2886

NASA Image and Video Library

2013-06-24

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, mission managers participate in a pre-launch dress rehearsal in the Launch Vehicle Data Center for NASA’s Interface Region Imaging Spectrograph, or IRIS, solar observatory. Scheduled for launch from Vandenberg on June 26 aboard an Orbital Sciences Pegasus XL rocket, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region in to the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun’s visible surface and upper atmosphere, is where most of the sun’s ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth’s climate. For more information, visit http://www.nasa.gov/iris. Photo credit: NASA/Daniel Casper

KSC-2013-2834

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – Technicians and engineers at Vandenberg Air Force Base in California mate the Pegasus XL rocket with the Interface Region Imaging Spectrograph, or IRIS, solar observatory to the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2742

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. – A look through the inside of the fuselage of the Orbital Sciences L-1011 aircraft called "Stargazer" after arrival at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2741

NASA Image and Video Library

2013-06-13

VANDENBERG ABF, Calif. – A look through the inside of the fuselage of the Orbital Sciences L-1011 aircraft called "Stargazer" after arrival at Vandenberg Air Force Base for the upcoming launch of the company's Pegasus XL rocket lifting NASA's IRIS solar observatory into orbit. The aircraft will carry the winged rocket to an altitude of 39,000 feet before releasing the Pegasus so its own motors can ignite to send the IRIS into space. The L-1011 is a modified airliner equipped to hold the Pegasus under its body safely. IRIS, short for Interface Region Imaging Spectrograph, is being prepared for launch from Vandenberg June 26. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

The Road to IRIS data products

NASA Astrophysics Data System (ADS)

Hurlburt, N. E.; Title, A. M.; De Pontieu, B.; Lemen, J. R.; Wuelser, J.; Tarbell, T. D.; Wolfson, C. J.; Schrijver, C. J.; Golub, L.; DeLuca, E. E.; Kankelborg, C. C.; Hansteen, V. H.; Carlsson, M.; Bush, R. I.

2013-12-01

The Interface Region Imaging Spectrograph generates a complex set of data products that the IRIS team has strived to deliver to the community in forms that are easy to find and use. We review the results of these efforts and invite the community to explore the data and tools. All standard IRIS data products are based on calibrated images are corrected for a variety of instrumental effects. The resulting products are incorporated into the Heliophysics Event Knowledgebase (HEK) as annotated data sets accessible through the HEK Coverage Registry (HCR). Annotations include descriptions of the data products themselves (pointing, field of view, cadence...) as well as references to coordinated observations from the Hinode mission and other observatories, and to solar events identified in the HEK Event Registry (HER). IRIS data products are available at the LMSAL and Stanford (JSOC) data centers in Palo Alto and the Hinode Data Center in Oslo. Portals that can help users to select data products include the LMSAL iSolsearch, the Virtual Solar Observatory and Helioviewer. Supporting analysis software is available in the IRIS branch of SolarSoft.

Optical Coherence Tomography Angiography Features of Iris Racemose Hemangioma in 4 Cases.

PubMed

Chien, Jason L; Sioufi, Kareem; Ferenczy, Sandor; Say, Emil Anthony T; Shields, Carol L

2017-10-01

Optical coherence tomography angiography (OCTA) allows visualization of iris racemose hemangioma course and its relation to the normal iris microvasculature. To describe OCTA features of iris racemose hemangioma. Descriptive, noncomparative case series at a tertiary referral center (Ocular Oncology Service of Wills Eye Hospital). Patients diagnosed with unilateral iris racemose hemangioma were included in the study. Features of iris racemose hemangioma on OCTA. Four eyes of 4 patients with unilateral iris racemose hemangioma were included in the study. Mean patient age was 50 years, all patients were white, and Snellen visual acuity was 20/20 in each case. All eyes had sectoral iris racemose hemangioma without associated iris or ciliary body solid tumor on clinical examination and ultrasound biomicroscopy. By anterior segment OCT, the racemose hemangioma was partially visualized in all cases. By OCTA, the hemangioma was clearly visualized as a uniform large-caliber vascular tortuous loop with intense flow characteristics superimposed over small-caliber radial iris vessels against a background of low-signal iris stroma. The vascular course on OCTA resembled a light bulb filament (filament sign), arising from the peripheral iris (base of light bulb) and forming a tortuous loop on reaching its peak (midfilament) near the pupil (n = 3) or midzonal iris (n = 1), before returning to the peripheral iris (base of light bulb). Intravenous fluorescein angiography performed in 1 eye depicted the iris hemangioma; however, small-caliber radial iris vessels were more distinct on OCTA than intravenous fluorescein angiography. Optical coherence tomography angiography is a noninvasive vascular imaging modality that clearly depicts the looping course of iris racemose hemangioma. Optical coherence tomography angiography depicted fine details of radial iris vessels, not distinct on intravenous fluorescein angiography.

An iris recognition algorithm based on DCT and GLCM

NASA Astrophysics Data System (ADS)

Feng, G.; Wu, Ye-qing

2008-04-01

With the enlargement of mankind's activity range, the significance for person's status identity is becoming more and more important. So many different techniques for person's status identity were proposed for this practical usage. Conventional person's status identity methods like password and identification card are not always reliable. A wide variety of biometrics has been developed for this challenge. Among those biologic characteristics, iris pattern gains increasing attention for its stability, reliability, uniqueness, noninvasiveness and difficult to counterfeit. The distinct merits of the iris lead to its high reliability for personal identification. So the iris identification technique had become hot research point in the past several years. This paper presents an efficient algorithm for iris recognition using gray-level co-occurrence matrix(GLCM) and Discrete Cosine transform(DCT). To obtain more representative iris features, features from space and DCT transformation domain are extracted. Both GLCM and DCT are applied on the iris image to form the feature sequence in this paper. The combination of GLCM and DCT makes the iris feature more distinct. Upon GLCM and DCT the eigenvector of iris extracted, which reflects features of spatial transformation and frequency transformation. Experimental results show that the algorithm is effective and feasible with iris recognition.

Iris recognition in the presence of ocular disease

PubMed Central

Aslam, Tariq Mehmood; Tan, Shi Zhuan; Dhillon, Baljean

2009-01-01

Iris recognition systems are among the most accurate of all biometric technologies with immense potential for use in worldwide security applications. This study examined the effect of eye pathology on iris recognition and in particular whether eye disease could cause iris recognition systems to fail. The experiment involved a prospective cohort of 54 patients with anterior segment eye disease who were seen at the acute referral unit of the Princess Alexandra Eye Pavilion in Edinburgh. Iris camera images were obtained from patients before treatment was commenced and again at follow-up appointments after treatment had been given. The principal outcome measure was that of mathematical difference in the iris recognition templates obtained from patients' eyes before and after treatment of the eye disease. Results showed that the performance of iris recognition was remarkably resilient to most ophthalmic disease states, including corneal oedema, iridotomies (laser puncture of iris) and conjunctivitis. Problems were, however, encountered in some patients with acute inflammation of the iris (iritis/anterior uveitis). The effects of a subject developing anterior uveitis may cause current recognition systems to fail. Those developing and deploying iris recognition should be aware of the potential problems that this could cause to this key biometric technology. PMID:19324690

Iris recognition in the presence of ocular disease.

PubMed

Aslam, Tariq Mehmood; Tan, Shi Zhuan; Dhillon, Baljean

2009-05-06

Iris recognition systems are among the most accurate of all biometric technologies with immense potential for use in worldwide security applications. This study examined the effect of eye pathology on iris recognition and in particular whether eye disease could cause iris recognition systems to fail. The experiment involved a prospective cohort of 54 patients with anterior segment eye disease who were seen at the acute referral unit of the Princess Alexandra Eye Pavilion in Edinburgh. Iris camera images were obtained from patients before treatment was commenced and again at follow-up appointments after treatment had been given. The principal outcome measure was that of mathematical difference in the iris recognition templates obtained from patients' eyes before and after treatment of the eye disease. Results showed that the performance of iris recognition was remarkably resilient to most ophthalmic disease states, including corneal oedema, iridotomies (laser puncture of iris) and conjunctivitis. Problems were, however, encountered in some patients with acute inflammation of the iris (iritis/anterior uveitis). The effects of a subject developing anterior uveitis may cause current recognition systems to fail. Those developing and deploying iris recognition should be aware of the potential problems that this could cause to this key biometric technology.

KSC-2012-2821

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – A truck carrying the third stage of the Orbital Sciences Pegasus XL rocket arrives at Vandenberg Air Force Base in California. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2820

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – A truck carrying all three stages of the Orbital Sciences Pegasus XL rocket arrives at Vandenberg Air Force Base in California. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2826

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – A truck carrying all three stages of the Orbital Sciences Pegasus XL rocket arrives at Vandenberg Air Force Base in California. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

Multi-wavelength Spectral Analysis of Ellerman Bombs Observed by FISS and IRIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Jie; Ding, M. D.; Cao, Wenda, E-mail: dmd@nju.edu.cn

Ellerman bombs (EBs) are a kind of solar activity that is suggested to occur in the lower solar atmosphere. Recent observations using the Interface Region Imaging Spectrograph (IRIS) show connections between EBs and IRIS bombs (IBs), which imply that EBs might be heated to a much higher temperature (8 × 10{sup 4} K) than previous results. Here we perform a spectral analysis of EBs simultaneously observed by the Fast Imaging Solar Spectrograph and IRIS. The observational results show clear evidence of heating in the lower atmosphere, indicated by the wing enhancement in H α , Ca ii 8542 Å, andmore » Mg ii triplet lines and also by brightenings in images of the 1700 Å and 2832 Å ultraviolet continuum channels. Additionally, the intensity of the Mg ii triplet line is correlated with that of H α when an EB occurs, suggesting the possibility of using the triplet as an alternative way to identify EBs. However, we do not find any signal in IRIS hotter lines (C ii and Si iv). For further analysis, we employ a two-cloud model to fit the two chromospheric lines (H α and Ca ii 8542 Å) simultaneously, and obtain a temperature enhancement of 2300 K for a strong EB. This temperature is among the highest of previous modeling results, albeit still insufficient to produce IB signatures at ultraviolet wavelengths.« less

MULTI-WAVELENGTH STUDY OF TRANSITION REGION PENUMBRAL SUBARCSECOND BRIGHT DOTS USING IRIS AND NST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Na; Liu, Chang; Xu, Yan

Using high-resolution transition region (TR) observations taken by the Interface Region Imaging Spectrograph ( IRIS ) mission, Tian et al. revealed numerous short-lived subarcsecond bright dots (BDs) above sunspots (mostly located in the penumbrae), which indicate yet unexplained small-scale energy releases. Moreover, whether or not these subarcsecond TR brightenings have any signature in the lower atmosphere and how they are formed are still not fully resolved. This paper presents a multi-wavelength study of the TR penumbral BDs using a coordinated observation of a near disk center sunspot with IRIS and the 1.6 m New Solar Telescope (NST) at the Bigmore » Bear Solar Observatory. NST provides high-resolution chromospheric and photospheric observations with narrowband H α imaging spectroscopy and broadband TiO images, respectively, complementary to IRIS TR observations. A total of 2692 TR penumbral BDs are identified from a 37 minute time series of IRIS 1400 Å slit-jaw images. Their locations tend to be associated more with downflowing and darker fibrils in the chromosphere, and weakly associated with bright penumbral features in the photosphere. However, temporal evolution analyses of the BDs show that there is no consistent and convincing brightening response in the chromosphere. These results are compatible with a formation mechanism of the TR penumbral BDs by falling plasma from coronal heights along more vertical and dense magnetic loops. The BDs may also be produced by small-scale impulsive magnetic reconnection taking place sufficiently high in the atmosphere that has no energy release in the chromosphere.« less

Workshop to Review Advances Made to the IRIS Process (Feb 2018)

EPA Pesticide Factsheets

NAS held a public workshop to review the progress made on the recommendations from the National Academies' National Research Council's May 2014 report on further improving the scientific quality of IRIS assessments.

Public Watches IRIS Launch Broadcast at NASA Ames (Reporter Pkg)

NASA Image and Video Library

2013-06-27

Crowds of space enthusiasts gathered at Ames Research Center to witness the broadcast of NASA's Interface Region Imaging Spectrograph or IRIS Mission as it launched from an aircraft out of Vandenberg Air Force Base in California. Speakers shared insights about the IRIS Mission and attendees cheered as the Pegasus rocket successfully separated from the L-1011 launch aircraft and proceeded to fire its rockets and launch into a polar orbit around the Earth.

Cross-sensor iris recognition through kernel learning.

PubMed

Pillai, Jaishanker K; Puertas, Maria; Chellappa, Rama

2014-01-01

Due to the increasing popularity of iris biometrics, new sensors are being developed for acquiring iris images and existing ones are being continuously upgraded. Re-enrolling users every time a new sensor is deployed is expensive and time-consuming, especially in applications with a large number of enrolled users. However, recent studies show that cross-sensor matching, where the test samples are verified using data enrolled with a different sensor, often lead to reduced performance. In this paper, we propose a machine learning technique to mitigate the cross-sensor performance degradation by adapting the iris samples from one sensor to another. We first present a novel optimization framework for learning transformations on iris biometrics. We then utilize this framework for sensor adaptation, by reducing the distance between samples of the same class, and increasing it between samples of different classes, irrespective of the sensors acquiring them. Extensive evaluations on iris data from multiple sensors demonstrate that the proposed method leads to improvement in cross-sensor recognition accuracy. Furthermore, since the proposed technique requires minimal changes to the iris recognition pipeline, it can easily be incorporated into existing iris recognition systems.

Fluorescein angiography of the iris in anterior segment pigment dispersal syndrome.

PubMed Central

Gillies, W E; Tangas, C

1986-01-01

The results are presented of fluorescein angiography of the iris in 11 patients with anterior segment pigment dispersal syndrome. These show a general hypovascularity of the iris with fine neovascularisation at the pupil margin and the peripupillary area. Hypoplasia of the iris stroma was also present in many cases. When the condition was virtually unilateral, the vascular changes were present though less marked in the relatively unaffected eye. It is postulated that the anterior segment pigment dispersal syndrome is secondary to a congenital mesodermal deficiency of the iris stroma with hypovascularity of the iris, which forms a poor support tissue for the pigment epithelium of the iris, resulting in shedding of pigment granules particularly in the region of the attachment of the dilator muscle to the pigment epithelium. The condition may be hereditary. Because of the hypovascularity the mesodermal hypoplasia may be progressive, but pigment release may diminish in later life with treatment, with consequent diminution of pupil activity. Images PMID:2421760

A multi-approach feature extractions for iris recognition

NASA Astrophysics Data System (ADS)

Sanpachai, H.; Settapong, M.

2014-04-01

Biometrics is a promising technique that is used to identify individual traits and characteristics. Iris recognition is one of the most reliable biometric methods. As iris texture and color is fully developed within a year of birth, it remains unchanged throughout a person's life. Contrary to fingerprint, which can be altered due to several aspects including accidental damage, dry or oily skin and dust. Although iris recognition has been studied for more than a decade, there are limited commercial products available due to its arduous requirement such as camera resolution, hardware size, expensive equipment and computational complexity. However, at the present time, technology has overcome these obstacles. Iris recognition can be done through several sequential steps which include pre-processing, features extractions, post-processing, and matching stage. In this paper, we adopted the directional high-low pass filter for feature extraction. A box-counting fractal dimension and Iris code have been proposed as feature representations. Our approach has been tested on CASIA Iris Image database and the results are considered successful.

Iris-based medical analysis by geometric deformation features.

PubMed

Ma, Lin; Zhang, D; Li, Naimin; Cai, Yan; Zuo, Wangmeng; Wang, Kuanguan

2013-01-01

Iris analysis studies the relationship between human health and changes in the anatomy of the iris. Apart from the fact that iris recognition focuses on modeling the overall structure of the iris, iris diagnosis emphasizes the detecting and analyzing of local variations in the characteristics of irises. This paper focuses on studying the geometrical structure changes in irises that are caused by gastrointestinal diseases, and on measuring the observable deformations in the geometrical structures of irises that are related to roundness, diameter and other geometric forms of the pupil and the collarette. Pupil and collarette based features are defined and extracted. A series of experiments are implemented on our experimental pathological iris database, including manual clustering of both normal and pathological iris images, manual classification by non-specialists, manual classification by individuals with a medical background, classification ability verification for the proposed features, and disease recognition by applying the proposed features. The results prove the effectiveness and clinical diagnostic significance of the proposed features and a reliable recognition performance for automatic disease diagnosis. Our research results offer a novel systematic perspective for iridology studies and promote the progress of both theoretical and practical work in iris diagnosis.

Eclipse-Free-Time Assessment Tool for IRIS

NASA Technical Reports Server (NTRS)

Eagle, David

2012-01-01

IRIS_EFT is a scientific simulation that can be used to perform an Eclipse-Free- Time (EFT) assessment of IRIS (Infrared Imaging Surveyor) mission orbits. EFT is defined to be those time intervals longer than one day during which the IRIS spacecraft is not in the Earth s shadow. Program IRIS_EFT implements a special perturbation of orbital motion to numerically integrate Cowell's form of the system of differential equations. Shadow conditions are predicted by embedding this integrator within Brent s method for finding the root of a nonlinear equation. The IRIS_EFT software models the effects of the following types of orbit perturbations on the long-term evolution and shadow characteristics of IRIS mission orbits. (1) Non-spherical Earth gravity, (2) Atmospheric drag, (3) Point-mass gravity of the Sun, and (4) Point-mass gravity of the Moon. The objective of this effort was to create an in-house computer program that would perform eclipse-free-time analysis. of candidate IRIS spacecraft mission orbits in an accurate and timely fashion. The software is a suite of Fortran subroutines and data files organized as a "computational" engine that is used to accurately predict the long-term orbit evolution of IRIS mission orbits while searching for Earth shadow conditions.

The IRIS Data Management Center: Enabling Access to Observational Time Series Spanning Decades

NASA Astrophysics Data System (ADS)

Ahern, T.; Benson, R.; Trabant, C.

2009-04-01

The Incorporated Research Institutions for Seismology (IRIS) is funded by the National Science Foundation (NSF) to operate the facilities to generate, archive, and distribute seismological data to research communities in the United States and internationally. The IRIS Data Management System (DMS) is responsible for the ingestion, archiving, curation and distribution of these data. The IRIS Data Management Center (DMC) manages data from more than 100 permanent seismic networks, hundreds of temporary seismic deployments as well as data from other geophysical observing networks such as magnetotelluric sensors, ocean bottom sensors, superconducting gravimeters, strainmeters, surface meteorological measurements, and in-situ atmospheric pressure measurements. The IRIS DMC has data from more than 20 different types of sensors. The IRIS DMC manages approximately 100 terabytes of primary observational data. These data are archived in multiple distributed storage systems that insure data availability independent of any single catastrophic failure. Storage systems include both RAID systems of greater than 100 terabytes as well as robotic tape robots of petabyte capacity. IRIS performs routine transcription of the data to new media and storage systems to insure the long-term viability of the scientific data. IRIS adheres to the OAIS Data Preservation Model in most cases. The IRIS data model requires the availability of metadata describing the characteristics and geographic location of sensors before data can be fully archived. IRIS works with the International Federation of Digital Seismographic Networks (FDSN) in the definition and evolution of the metadata. The metadata insures that the data remain useful to both current and future generations of earth scientists. Curation of the metadata and time series is one of the most important activities at the IRIS DMC. Data analysts and an automated quality assurance system monitor the quality of the incoming data. This insures data are of acceptably high quality. The formats and data structures used by the seismological community are esoteric. IRIS and its FDSN partners are developing web services that can transform the data holdings to structures that are more easily used by broader scientific communities. For instance, atmospheric scientists are interested in using global observations of microbarograph data but that community does not understand the methods of applying instrument corrections to the observations. Web processing services under development at IRIS will transform these data in a manner that allows direct use within such analysis tools as MATLAB® already in use by that community. By continuing to develop web-service based methods of data discovery and access, IRIS is enabling broader access to its data holdings. We currently support data discovery using many of the Open Geospatial Consortium (OGC) web mapping services. We are involved in portal technologies to support data discovery and distribution for all data from the EarthScope project. We are working with computer scientists at several universities including the University of Washington as part of a DataNet proposal and we intend to enhance metadata, further develop ontologies, develop a Registry Service to aid in the discovery of data sets and services, and in general improve the semantic interoperability of the data managed at the IRIS DMC. Finally IRIS has been identified as one of four scientific organizations that the External Research Division of Microsoft wants to work with in the development of web services and specifically with the development of a scientific workflow engine. More specific details of current and future developments at the IRIS DMC will be included in this presentation.

Does Iris Change Over Time?

PubMed Central

Mehrotra, Hunny; Vatsa, Mayank; Singh, Richa; Majhi, Banshidhar

2013-01-01

Iris as a biometric identifier is assumed to be stable over a period of time. However, some researchers have observed that for long time lapse, the genuine match score distribution shifts towards the impostor score distribution and the performance of iris recognition reduces. The main purpose of this study is to determine if the shift in genuine scores can be attributed to aging or not. The experiments are performed on the two publicly available iris aging databases namely, ND-Iris-Template-Aging-2008–2010 and ND-TimeLapseIris-2012 using a commercial matcher, VeriEye. While existing results are correct about increase in false rejection over time, we observe that it is primarily due to the presence of other covariates such as blur, noise, occlusion, and pupil dilation. This claim is substantiated with quality score comparison of the gallery and probe pairs. PMID:24244305

Does iris change over time?

PubMed

Mehrotra, Hunny; Vatsa, Mayank; Singh, Richa; Majhi, Banshidhar

2013-01-01

Iris as a biometric identifier is assumed to be stable over a period of time. However, some researchers have observed that for long time lapse, the genuine match score distribution shifts towards the impostor score distribution and the performance of iris recognition reduces. The main purpose of this study is to determine if the shift in genuine scores can be attributed to aging or not. The experiments are performed on the two publicly available iris aging databases namely, ND-Iris-Template-Aging-2008-2010 and ND-TimeLapseIris-2012 using a commercial matcher, VeriEye. While existing results are correct about increase in false rejection over time, we observe that it is primarily due to the presence of other covariates such as blur, noise, occlusion, and pupil dilation. This claim is substantiated with quality score comparison of the gallery and probe pairs.

Association of iris surface features with iris parameters assessed by swept-source optical coherence tomography in Asian eyes.

PubMed

Tun, Tin A; Chua, Jacqueline; Shi, Yuan; Sidhartha, Elizabeth; Thakku, Sri Gowtham; Shei, William; Tan, Marcus Chiang Lee; Quah, Joanne Hui Min; Aung, Tin; Cheng, Ching-Yu

2016-12-01

To characterise the association of iris surface features (crypts, furrows and colour) with iris volume and curvature assessed by swept-source optical coherence tomography (SSOCT) in Asian eyes. Iris crypts (by number and size) and furrows (by number and circumferential extent) were graded from iris photographs. Iris colour was measured by a customised algorithm written on MATLAB (MathWorks, Natick, Massachusetts, USA). The iris was imaged by SSOCT (SS-1000, CASIA, Tomey, Nagoya, Japan). The associations of surface features with iris parameters were analysed using a generalised estimating equation. A total of 1704 subjects (3297 eyes) were included in the analysis. The majority was Chinese (86.4%), and 63.2% were females, and their mean age (±SD) was 61.4±6.6 years. After adjusting for age, sex, ethnicity, pupil size and corneal arcus, higher iris crypt grade was independently associated with smaller iris volume (β=-0.54, p<0.001), whereas darker irides and higher iris furrow grade were associated with larger iris volume (β=-0.041, p<0.001) and (β=0.233, p<0.001), respectively. Lighter coloured irides with more crypts and/or more furrows were also associated with less convexity (crypts: β=-0.003, p=0.03; furrows: β=-0.004, p=0.007; and colour: β=-0.001, p=0.005). Iris surface features were highly correlated with iris volume and curvature. Irides with more crypts have a smaller volume; and darker irides with more furrows have a larger volume. Lighter irides with more crypts and/or furrows have less convexity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

KSC-2012-2824

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – Inside a hangar at Vandenberg Air Force Base in California, technicians offload the second stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2828

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – At Vandenberg Air Force Base in California, technicians prepare to offload the first stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2827

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – At Vandenberg Air Force Base in California, technicians prepare to offload the first stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2825

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – Inside a hangar at Vandenberg Air Force Base in California, technicians offload the second stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2822

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – Inside a hangar at Vandenberg Air Force Base in California, technicians prepare to offload the third stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2831

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – At Vandenberg Air Force Base in California, technicians offload the first stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2829

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – At Vandenberg Air Force Base in California, technicians prepare to offload the first stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2830

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – At Vandenberg Air Force Base in California, technicians offload the first stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-2823

NASA Image and Video Library

2012-05-11

Vandenberg Air Force Base, Calif. – Inside a hangar at Vandenberg Air Force Base in California, technicians prepare to offload the third stage of the Orbital Sciences Pegasus XL rocket from the truck in which it was transported. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2013-2204

NASA Image and Video Library

2013-04-25

VANDENBERG AIR FORCE BASE, Calif. -- Half of the fairing that will be fitted to the nose of the Orbital Sciences Corp. Pegasus XL rocket is ready for its installation around the Interface Region Imaging Spectrograph, or IRIS, spacecraft. The fairing will protect the spacecraft from atmospheric heating and stress during launch. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2012-4672

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians assist as a crane moves the wing closer for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-4677

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians assist as a crane lowers the wing closer for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-4674

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians assist as a crane moves the wing closer for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-4673

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians assist as a crane moves the wing closer for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-4671

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians prepare the wing for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-4675

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians assist as a crane lowers the wing closer for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-4676

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians assist as a crane lowers the wing closer for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

KSC-2012-4670

NASA Image and Video Library

2012-08-21

Vandenberg Air Force Base, Calif. – Inside a processing facility at Vandenberg Air Force Base in California, technicians prepare the wing for a fit check with the Orbital Sciences Pegasus XL launch vehicle. NASA’s Interface Region Imaging Spectrograph, or IRIS, spacecraft will launch aboard the Pegasus XL in late 2012. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and heliosphere, or region around the sun. Photo credit: NASA/Randy Beaudoin

NASA HyspIRI Workshop Report

USDA-ARS?s Scientific Manuscript database

On October 21-23rd 2008 NASA held a three-day workshop to consider the Hyperspectral and Infrared Imager (HyspIRI) mission recommended for implementation by the 2007 National Research Council Earth Science Decadal Survey. The open workshop provided a forum to present the initial observational requir...

IRIS - A concept for microwave sensing of soil moisture and ocean salinity

NASA Technical Reports Server (NTRS)

Moghaddam, M.; Njoku, E.

1997-01-01

A concept is described for passive microwave sensing of soil moisture and ocean salinity from space. The Inflatable Radiometric Imaging System (IRIS) makes use of a large-diameter, offset-fed, parabolic-torus antenna with multiple feeds, in a conical pushbroom configuration.

Region based feature extraction from non-cooperative iris images using triplet half-band filter bank

NASA Astrophysics Data System (ADS)

Barpanda, Soubhagya Sankar; Majhi, Banshidhar; Sa, Pankaj Kumar

2015-09-01

In this paper, we have proposed energy based features using a multi-resolution analysis (MRA) on iris template. The MRA is based on our suggested triplet half-band filter bank (THFB). The THFB derivation process is discussed in detail. The iris template is divided into six equispaced sub-templates and two level decomposition has been made to each sub-template using THFB except second one. The reason for discarding the second template is due to the fact that it mostly contains the noise due to eyelids, eyelashes, and occlusion due to segmentation failure. Subsequently, energy features are derived from the decomposed coefficients of each sub-template. The proposed feature has been experimented on standard databases like CASIAv3, UBIRISv1, and IITD and mostly on iris images which encounter a segmentation failure. Comparative analysis has been done with existing features based on Gabor transform, Fourier transform, and CDF 9/7 filter bank. The proposed scheme shows superior performance with respect to FAR, GAR and AUC.

KSC-2013-2835

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the Pegasus XL rocket with the attached Interface Region Imaging Spectrograph IRIS solar observatory rolled out of the hangar on its transporter to the runway at Vandenberg. There, the rocket and spacecraft were mated with the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2839

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the Pegasus XL rocket with the attached Interface Region Imaging Spectrograph IRIS solar observatory rolled out of the hangar on its transporter to the runway at Vandenberg. There, the rocket and spacecraft were mated with the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2837

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the Pegasus XL rocket with the attached Interface Region Imaging Spectrograph IRIS solar observatory rolled out of the hangar on its transporter to the runway at Vandenberg. There, the rocket and spacecraft were mated with the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2840

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the Pegasus XL rocket with the attached Interface Region Imaging Spectrograph IRIS solar observatory rolled out of the hangar on its transporter to the runway at Vandenberg. There, the rocket and spacecraft were mated with the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

KSC-2013-2843

NASA Image and Video Library

2013-06-19

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, the Pegasus XL rocket with the attached Interface Region Imaging Spectrograph IRIS solar observatory rolled out of the hangar on its transporter to the runway at Vandenberg. There, the rocket and spacecraft were mated with the Orbital Sciences L-1011 carrier aircraft. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/Randy Beaudoin

Multimodal imaging of bilateral diffuse uveal melanocytic proliferation associated with an iris mass lesion.

PubMed

Naysan, Jonathan; Pang, Claudine E; Klein, Robert W; Freund, K Bailey

2016-01-01

Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a rare, paraneoplastic syndrome characterized by bilateral painless visual loss and proliferation of choroidal melanocytes in association with an underlying systemic malignancy. We report a case of bilateral diffuse uveal melanocytic proliferation associated with an underlying gynecological malignancy that also features the infrequent finding of an iris mass lesion, using multimodal imaging including ultra-widefield imaging, spectral domain and swept-source optical coherence tomography. A 59-year-old white female with a prior history of gynecological malignancy in remission presented with progressive bilateral visual loss over several weeks. The patient was noted to have a focal iris mass lesion in her right eye. Ultra-widefield color fundus photography showed a characteristic bilateral 'giraffe pattern' of pigmentary changes extending into the periphery as well as multiple discrete deeply pigmented lesions. Ultra-widefield autofluorescence was useful for visualizing the full extent of involvement. Indocyanine green angiography helped to demarcate the discrete pigmented choroidal lesions. Swept-source OCT clearly delineated the alternating zones of retinal pigment epithelium (RPE) thickening and RPE loss, as well as the prominent choroidal infiltration and thickening. BDUMP is an important diagnosis to consider in the presence of multiple discrete melanocytic choroidal lesions, diffuse choroidal thickening, characteristic RPE changes, iris mass lesions and exudative retinal detachment. Ultra-widefield imaging may demonstrate more extensive lesions than that detected on clinical examination or standard field imaging. Imaging with SS-OCT shows choroidal and RPE characteristics that correlate well with known histopathology of this entity.

SUMER-IRIS Observations of AR11875

NASA Astrophysics Data System (ADS)

Schmit, Donald; Innes, Davina

2014-05-01

We present results of the first joint observing campaign of IRIS and SOHO/SUMER. While the IRIS datasets provide information on the chromosphere and transition region, SUMER provides complementary diagnostics on the corona. On 2013-10-24, we observed an active region, AR11875, and the surrounding plage for approximately 4 hours using rapid-cadence observing programs. These datasets include spectra from a small C -class flare which occurs in conjunction with an Ellerman-bomb type event. Our analysis focusses on how the high spatial resolution and slit jaw imaging capabilities of IRIS shed light on the unresolved structure of transient events in the SUMER catalog.

Immunogold localisation of laminin in normal and exfoliative iris.

PubMed Central

Konstas, A. G.; Marshall, G. E.; Lee, W. R.

1990-01-01

Immunoelectron microscopic studies of exfoliative iris tissue (seven specimens) revealed the presence of laminin in the fibrillar component of exfoliation material. The immunogold label was uniformly distributed on the exfoliation fibres. Deposition of laminin labelled exfoliation material in the dilator muscle was a noteworthy feature, as was an apparent depletion of laminin in the basement membranes of ostensibly unaffected vessels. In control iris tissue (five enucleated eyes) laminin was identified in the basement membrane round vascular contractile cells, but not beneath the endothelium. Images PMID:2390517

Secure and Robust Iris Recognition Using Random Projections and Sparse Representations.

PubMed

Pillai, Jaishanker K; Patel, Vishal M; Chellappa, Rama; Ratha, Nalini K

2011-09-01

Noncontact biometrics such as face and iris have additional benefits over contact-based biometrics such as fingerprint and hand geometry. However, three important challenges need to be addressed in a noncontact biometrics-based authentication system: ability to handle unconstrained acquisition, robust and accurate matching, and privacy enhancement without compromising security. In this paper, we propose a unified framework based on random projections and sparse representations, that can simultaneously address all three issues mentioned above in relation to iris biometrics. Our proposed quality measure can handle segmentation errors and a wide variety of possible artifacts during iris acquisition. We demonstrate how the proposed approach can be easily extended to handle alignment variations and recognition from iris videos, resulting in a robust and accurate system. The proposed approach includes enhancements to privacy and security by providing ways to create cancelable iris templates. Results on public data sets show significant benefits of the proposed approach.

Iris Crypts Influence Dynamic Changes of Iris Volume.

PubMed

Chua, Jacqueline; Thakku, Sri Gowtham; Tun, Tin A; Nongpiur, Monisha E; Tan, Marcus Chiang Lee; Girard, Michael J A; Wong, Tien Yin; Quah, Joanne Hui Min; Aung, Tin; Cheng, Ching-Yu

2016-10-01

To determine the association of iris surface features with iris volume change after physiologic pupil dilation in adults. Cross-sectional observational study. Chinese adults aged ≥ 50 years without ocular diseases. Digital iris photographs were taken from eyes of each participant and graded for crypts (by number and size) and furrows (by number and circumferential extent) following a standardized grading scheme. Iris color was measured objectively, using the Commission Internationale de l'Eclairage (CIE) L* color parameter (higher value denoting lighter iris). The anterior segment was imaged by swept-source optical coherence tomography (SS-OCT) (Casia; Tomey, Nagoya, Japan) under bright light and dark room conditions. Iris volumes in light and dark conditions were measured with custom semiautomated software, and the change in iris volume was quantified. Associations of the change in iris volume after pupil dilation with underlying iris surface features in right eyes were assessed using linear regression analysis. Iris volume change after physiologic pupil dilation from light to dark condition. A total of 65 Chinese participants (mean age, 59.8±5.7 years) had gradable data for iris surface features. In light condition, higher iris crypt grade was associated independently with smaller iris volume (β [change in iris volume in millimeters per crypt grade increment] = -1.43, 95% confidence interval [CI], -2.26 to -0.59; P = 0.001) and greater reduction of iris volume on pupil dilation (β [change in iris volume in millimeters per crypt grade increment] = 0.23, 95% CI, 0.06-0.40; P = 0.010), adjusting for age, gender, presence of corneal arcus, and change in pupil size. Iris furrows and iris color were not associated with iris volume in light condition or change in iris volume (all P > 0.05). Although few Chinese persons have multiple crypts on their irides, irides with more crypts were significantly thinner and lost more volume on pupil dilation. In view that the latter feature is known to be protective for acute angle-closure attack, it is likely that the macroscopic and microscopic composition of the iris is a contributing feature to angle-closure disease. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

PHyTIR - A Prototype Thermal Infrared Radiometer

NASA Technical Reports Server (NTRS)

Jau, Bruno M.; Hook, Simon J.; Johnson, William R.; Foote, Marc C.; Paine, Christopher G.; Pannell, Zack W.; Smythe, Robert F.; Kuan, Gary M.; Jakoboski, Julie K.; Eng, Bjorn T.

2013-01-01

This paper describes the PHyTIR (Prototype HyspIRI Thermal Infrared Radiometer) instrument, which is the engineering model for the proposed HyspIRI (Hyperspectral Infrared Imager) earth observing instrument. The HyspIRI mission would be comprised of the HyspIRI TIR (Thermal Infrared Imager), and a VSWIR (Visible Short-Wave Infra-Red Imaging Spectrometer). Both instruments would be used to address key science questions related to the earth's carbon cycle, ecosystems, climate, and solid earth properties. Data gathering of volcanic activities, earthquakes, wildfires, water use and availability, urbanization, and land surface compositions and changes, would aid the predictions and evaluations of such events and the impact they create. Even though the proposed technology for the HyspIRI imager is mature, the PHyTIR prototype is needed to advance the technology levels for several of the instrument's key components, and to reduce risks, in particular to validate 1) the higher sensitivity, spatial resolution, and higher throughput required for this focal plane array, 2) the pointing accuracy, 2) the characteristics of several spectral channels, and 4) the use of ambient temperature optics. The PHyTIR telescope consists of the focal plane assembly that is housed within a cold housing located inside a vacuum enclosure; all mounted to a bulkhead, and an optical train that consists of 3 powered mirrors; extending to both sides of the bulkhead. A yoke connects the telescope to a scan mirror. The rotating mirror enables to scan- a large track on the ground. This structure is supported by kinematic mounts, linking the telescope assembly to a base plate that would also become the spacecraft interface for HyspIRI. The focal plane's cooling units are also mounted to the base plate, as is an overall enclosure that has two viewing ports with large exterior baffles, shielding the focal plane from incoming stray light. PHyTIR's electronics is distributed inside and near the vacuum enclosure, and in a nearby rack. The data acquisition technique would be to take measurements over a 51deg wide swath in the cross spacecraft velocity direction, which is brought into view through the rotating scan mirror. A landscape mosaic thus can be assembled by overlaying rows of measurements. The paper briefly outlines the proposed HyspIRI mission and its data acquisition technique; it then describes the prototype PHyTIR instrument.

KSC-2013-2205

NASA Image and Video Library

2013-04-25

VANDENBERG AIR FORCE BASE, Calif. -- The Interface Region Imaging Spectrograph, or IRIS, is being readied for mating to the Orbital Sciences Corp. Pegasus XL rocket that will launch the spacecraft. A fairing will be fitted to the nose of the Pegasus to protect the spacecraft from atmospheric heating and stress during launch. Upcoming work includes electrical verification testing. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2206

NASA Image and Video Library

2013-04-25

VANDENBERG AIR FORCE BASE, Calif. -- The Interface Region Imaging Spectrograph, or IRIS, is being readied for mating to the Orbital Sciences Corp. Pegasus XL rocket that will launch the spacecraft. A fairing will be fitted to the nose of the Pegasus to protect the spacecraft from atmospheric heating and stress during launch. Upcoming work includes electrical verification testing. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

KSC-2013-2207

NASA Image and Video Library

2013-04-25

VANDENBERG AIR FORCE BASE, Calif. -- The Interface Region Imaging Spectrograph, or IRIS, is being readied for mating to the Orbital Sciences Corp. Pegasus XL rocket that will launch the spacecraft. A fairing will be fitted to the nose of the Pegasus to protect the spacecraft from atmospheric heating and stress during launch. Upcoming work includes electrical verification testing. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. Photo credit: VAFB/Randy Beaudoin

The Evolution of Transition Region Loops Using IRIS and AIA

NASA Technical Reports Server (NTRS)

Winebarger, Amy R.; DePontieu, Bart

2014-01-01

Over the past 50 years, the model for the structure of the solar transition region has evolved from a simple transition layer between the cooler chromosphere to the hotter corona to a complex and diverse region that is dominated by complete loops that never reach coronal temperatures. The IRIS slitjaw images show many complete transition region loops. Several of the "coronal" channels in the SDO AIA instrument include contributions from weak transition region lines. In this work, we combine slitjaw images from IRIS with these channels to determine the evolution of the loops. We develop a simple model for the temperature and density evolution of the loops that can explain the simultaneous observations. Finally, we estimate the percentage of AIA emission that originates in the transition region.

Infrared photothermal imaging of trace explosives on relevant substrates

NASA Astrophysics Data System (ADS)

Kendziora, Christopher A.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; Borchert, James; Byers, Jeff; McGill, R. Andrew

2013-06-01

We are developing a technique for the stand-off detection of trace explosives on relevant substrate surfaces using photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). This approach leverages one or more compact IR quantum cascade lasers, tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface and detect small increases in thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. The ability to detect trace analytes on relevant substrates is critical for stand-off applications, but is complicated by the optical and thermal analyte/substrate interactions. This manuscript describes recent PT-IRIS experimental results and analysis for traces of RDX, TNT, ammonium nitrate (AN) and sucrose on relevant substrates (steel, polyethylene, glass and painted steel panels). We demonstrate that these analytes can be detected on these substrates at relevant surface mass loadings (10 μg/cm2 to 100 μg/cm2) even at the single pixel level.

Hurricane Iris Hits Belize

NASA Technical Reports Server (NTRS)

2002-01-01

Hurricane Iris hit the small Central American country of Belize around midnight on October 8, 2001. At the time, Iris was the strongest Atlantic hurricane of the season, with sustained winds up to 225 kilometers per hour (140 mph). The hurricane caused severe damage-destroying homes, flooding streets, and leveling trees-in coastal towns south of Belize City. In addition, a boat of American recreational scuba divers docked along the coast was capsized by the storm, leaving 20 of the 28 passengers missing. Within hours the winds had subsided to only 56 kph (35 mph), a modest tropical depression, but Mexico, Guatemala, El Salvador, and Honduras were still expecting heavy rains. The above image is a combination of visible and thermal infrared data (for clouds) acquired by a NOAA Geostationary Operational Environmental Satellite (GOES-8) on October 8, 2001, at 2:45 p.m., and the Moderate-resolution Imaging Spectroradiometer (MODIS) (for the color of the ground). The three-dimensional view is from the south-southeast (north is towards the upper left). Belize is off the image to the left. Image courtesy Marit Jentoft-Nilsen, NASA GSFC Visualization Analysis Lab

Infrared photothermal imaging spectroscopy for detection of trace explosives on surfaces.

PubMed

Kendziora, Christopher A; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; Byers, Jeff; Andrew McGill, R

2015-11-01

We are developing a technique for the standoff detection of trace explosives on relevant substrate surfaces using photothermal infrared (IR) imaging spectroscopy (PT-IRIS). This approach leverages one or more compact IR quantum cascade lasers, which are tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface and detect increases in thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral, and temporal dimensions as vectors within a detection algorithm. The ability to detect trace analytes at standoff on relevant substrates is critical for security applications but is complicated by the optical and thermal analyte/substrate interactions. This manuscript describes a series of PT-IRIS experimental results and analysis for traces of RDX, TNT, ammonium nitrate, and sucrose on steel, polyethylene, glass, and painted steel panels. We demonstrate detection at surface mass loadings comparable with fingerprint depositions ( 10μg/cm2 to 100μg/cm2) from an area corresponding to a single pixel within the thermal image.

Preparing NASA's Next Solar Satellite for Launch

NASA Image and Video Library

2017-12-08

Orbital Sciences team members move the second half of the payload fairing before it is placed over NASA's IRIS (Interface Region Imaging Spectrograph) spacecraft. The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit. The work is taking place in a hangar at Vandenberg Air Force Base, where IRIS is being prepared for launch on a Pegasus XL rocket. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun's corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. High res file available here: 1.usa.gov/11yal3w Photo Credit: NASA/Tony Vauclin NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

How Reliable Are Informal Reading Inventories?

ERIC Educational Resources Information Center

Spector, Janet E.

2005-01-01

Informal Reading Inventories (IRI) are often recommended as instructionally relevant measures of reading. However, they have also been criticized for inattention to technical quality. Examination of reliability evidence in nine recently revised IRIs revealed that fewer than half report reliability. Several appear to have sufficient reliability for…

Correlation between Visible Length of the Iris and the Length of the Maxillary Central Incisor Using Digital Image Analysis- A Pilot Study.

PubMed

Rohini; Hemalatha; Chander, Gopi Naveen; Anitha, Kuttae Viswanathan

2017-02-01

Complete denture therapy is one such modality where science and art goes hand in hand. Selection of artificial teeth for completely edentulous patients is not easy in the absence of pre extraction records, because till date concrete guidelines do not exist. The purpose of this study was to determine if a correlation existed between the visible length of the iris and the length of the maxillary central incisor to potentially provide a guide for teeth selection. A total of 20 Indian dental students consented to participate in the pilot study. Standardized digital images of the face revealing the eyes and component of teeth on smiling was captured using a digital camera. The digital measurements of the visible iris length (medial aperture height, tangential to iris) and the length of the maxillary central incisor from the zenith to the incisal edge were analysed using Adobe Photoshop creative cloud software. The data was statistically evaluated and results were tabulated. Karl Pearson's Coefficient of Correlation was utilized to detect if any association existed between the two variables. The mean value of length of central incisor was 10.39 mm and the mean value of the visible length of iris was found to be 12.9 mm. A Pearson correlation analysis revealed an r-value <0.3 indicating minimal association between the two variables with a p-value >0.01 (.322). On inference, the correlation between the visible iris length and that of maxillary central incisor were unable to produce a strong positive statistical association. However, an association factor between the two has been obtained. Deduction of 2.5 mm from the dimension of visible iris length will help in attaining the length of artificial maxillary central incisor tooth.

Excimer Laser Surgery: Biometrical Iris Eye Recognition with Cyclorotational Control Eye Tracker System.

PubMed

Pajic, Bojan; Cvejic, Zeljka; Mijatovic, Zoran; Indjin, Dragan; Mueller, Joerg

2017-05-25

A prospective comparative study assessing the importance of the intra-operative dynamic rotational tracking-especially in the treatment of astigmatisms in corneal refractive Excimer laser correction-concerning clinical outcomes is presented. The cyclotorsion from upright to supine position was measured using iris image comparison. The Group 1 of patients was additionally treated with cyclorotational control and Group 2 only with X-Y control. Significant differences were observed between the groups regarding the mean postoperative cylinder refraction ( p < 0.05). The mean cyclotorsion can be calculated to 3.75° with a standard deviation of 3.1°. The total range of torsion was from -14.9° to +12.6°. Re-treatment rate was 2.2% in Group 1 and 8.2% in Group 2, which is highly significant ( p < 0.01). The investigation confirms that the dynamic rotational tracking system used for LASIK results in highly predictable refraction quality with significantly less postoperative re-treatments.

Excimer Laser Surgery: Biometrical Iris Eye Recognition with Cyclorotational Control Eye Tracker System

PubMed Central

Pajic, Bojan; Cvejic, Zeljka; Mijatovic, Zoran; Indjin, Dragan; Mueller, Joerg

2017-01-01

A prospective comparative study assessing the importance of the intra-operative dynamic rotational tracking—especially in the treatment of astigmatisms in corneal refractive Excimer laser correction—concerning clinical outcomes is presented. The cyclotorsion from upright to supine position was measured using iris image comparison. The Group 1 of patients was additionally treated with cyclorotational control and Group 2 only with X-Y control. Significant differences were observed between the groups regarding the mean postoperative cylinder refraction (p < 0.05). The mean cyclotorsion can be calculated to 3.75° with a standard deviation of 3.1°. The total range of torsion was from −14.9° to +12.6°. Re-treatment rate was 2.2% in Group 1 and 8.2% in Group 2, which is highly significant (p < 0.01). The investigation confirms that the dynamic rotational tracking system used for LASIK results in highly predictable refraction quality with significantly less postoperative re-treatments. PMID:28587100

Hi-C Observations of Penumbral Bright Dots: Comparison with the IRIS Results

NASA Technical Reports Server (NTRS)

Alpert, S. E.; Tiwari, S. K.; Moore, R. L.; Savage, S. L.; Winebarger, A. R.

2014-01-01

We observed bright dots (BDs) in a sunspot penumbra by using data acquired by the High Resolution Coronal Imager (Hi-C). The sizes of these BDs are on the order of 1 arcsecond (1') and are therefore hard to identify using the Atmospheric Imaging Assembly's (AIA) 0.6' pixel -1 resolution. These BDs become readily apparent with Hi-C's 0.1' pixel -1 resolution. Tian et al. (2014) found penumbral BDs in the transition region (TR) by using the Interface Region Imaging Spectrograph (IRIS). However, only a few of their dots could be associated with any enhanced brightness in AIA channels. In this work, we examine the characteristics of the penumbral BDs observed by Hi-C in a sunspot penumbra, including their sizes, lifetimes, speeds, and intensity. We also attempt to relate these BDs to the IRIS BDs. There are fewer Hi-C BDs in the penumbra than seen by IRIS, though different sunspots were studied and Hi-C had a short observation time. We use 193 A Hi-C data from July 11, 2012 which observed from 18:52:00 UT{18:56:00 UT and supplement it with data from AIA's 193 A passband to see the complete lifetime of the dots that were born before and/or lasted longer than Hi-C's 5-minute observation period. We use additional AIA passbands and compare the light curves of the BDs at different temperatures to test whether the Hi-C BDs are TR BDs. We find that most Hi-C BDs show clear movement, and of those that do, they move in a radial direction, toward or away from the sunspot umbra, sometimes doing both. BDs interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to move less and last longer. We examine the properties of the Hi-C BDs and compare them with the IRIS BDs. Our BDs are similar to the exceptional values of the IRIS BDs: they move slower on average and their sizes and lifetimes are on the higher end of the distributions of IRIS BDs. We infer that our penumbral BDs are some of the larger BDs observed by IRIS.

From the Ground Up: Building an Earth Science Satellite (HyspIRI Hawaii, Part 4)

NASA Image and Video Library

2017-04-20

Flying high aboard NASA’s ER-2, the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) uses over 224 sensors to identify, measure, and monitor natural features of the Earth's surface and atmosphere based on reflective light from the sun. The instrument was recently used for the Hyperspectral InfraRed Imager (HyspIRI) airborne preparatory mission, which focused on observing coral reef health and volcano emissions and eruptions around the Hawaiian Islands. Data from this mission will help develop a NASA satellite to study natural hazards and ecosystems. The Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) instrument is developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, California. NASA’s ER-2 aircraft is managed and based at NASA’s Armstrong Flight Research Center, Building 703 in Palmdale, California. Read more about the HyspIRI Hawaii mission here: https://www.nasa.gov/feature/jpl/nasa-tests-observing-capability-on-hawaiis-coral-reefs https://www.nasa.gov/feature/jpl/nasa-led-campaign-studies-hawaii-s-iconic-volcanoes

From the Ground Up: Building an Earth Science Satellite (HyspIRI Hawaii, Part 2)

NASA Image and Video Library

2017-04-03

Flying high aboard NASA’s ER-2, the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) uses over 224 sensors to identify, measure, and monitor natural features of the Earth's surface and atmosphere based on reflective light from the sun. The instrument was recently used for the Hyperspectral InfraRed Imager (HyspIRI) airborne preparatory mission, which focused on observing coral reef health and volcano emissions and eruptions around the Hawaiian Islands. Data from this mission will help develop a NASA satellite to study natural hazards and ecosystems. The Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) instrument is developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, California. NASA’s ER-2 aircraft is managed and based at NASA’s Armstrong Flight Research Center, Building 703 in Palmdale, California. Read more about the HyspIRI Hawaii mission here: https://www.nasa.gov/feature/jpl/nasa-tests-observing-capability-on-hawaiis-coral-reefs https://www.nasa.gov/feature/jpl/nasa-led-campaign-studies-hawaii-s-iconic-volcanoes

From the Ground Up: Building an Earth Science Satellite (HyspIRI Hawaii, Part 3)

NASA Image and Video Library

2017-04-12

Flying high aboard NASA’s ER-2, the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) uses over 224 sensors to identify, measure, and monitor natural features of the Earth's surface and atmosphere based on reflective light from the sun. The instrument was recently used for the Hyperspectral InfraRed Imager (HyspIRI) airborne preparatory mission, which focused on observing coral reef health and volcano emissions and eruptions around the Hawaiian Islands. Data from this mission will help develop a NASA satellite to study natural hazards and ecosystems. The Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) instrument is developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, California. NASA’s ER-2 aircraft is managed and based at NASA’s Armstrong Flight Research Center, Building 703 in Palmdale, California. Read more about the HyspIRI Hawaii mission here: https://www.nasa.gov/feature/jpl/nasa-tests-observing-capability-on-hawaiis-coral-reefs https://www.nasa.gov/feature/jpl/nasa-led-campaign-studies-hawaii-s-iconic-volcanoes

Noninvasive in vivo glucose sensing using an iris based technique

NASA Astrophysics Data System (ADS)

Webb, Anthony J.; Cameron, Brent D.

2011-03-01

Physiological glucose monitoring is important aspect in the treatment of individuals afflicted with diabetes mellitus. Although invasive techniques for glucose monitoring are widely available, it would be very beneficial to make such measurements in a noninvasive manner. In this study, a New Zealand White (NZW) rabbit animal model was utilized to evaluate a developed iris-based imaging technique for the in vivo measurement of physiological glucose concentration. The animals were anesthetized with isoflurane and an insulin/dextrose protocol was used to control blood glucose concentration. To further help restrict eye movement, a developed ocular fixation device was used. During the experimental time frame, near infrared illuminated iris images were acquired along with corresponding discrete blood glucose measurements taken with a handheld glucometer. Calibration was performed using an image based Partial Least Squares (PLS) technique. Independent validation was also performed to assess model performance along with Clarke Error Grid Analysis (CEGA). Initial validation results were promising and show that a high percentage of the predicted glucose concentrations are within 20% of the reference values.

Measuring the quality of infection control in Dutch nursing homes using a standardized method; the Infection prevention RIsk Scan (IRIS)

PubMed Central

2014-01-01

Background We developed a standardised method to assess the quality of infection control in Dutch Nursing Home (NH), based on a cross-sectional survey that visualises the results. The method was called the Infection control RIsk Infection Scan (IRIS). We tested the applicability of this new tool in a multicentre surveillance executed June and July 2012. Methods The IRIS includes two patient outcome-variables, i.e. the prevalence of healthcare associated infections (HAI) and rectal carriage of Extended-Spectrum Beta-Lactamase (ESBL) producing Enterobacteriaceae (ESBL-E); two patient-related risk factors, i.e. use of medical devices, and antimicrobial therapy; and three ward-related risk factors, i.e. environmental contamination, availability of local guidelines, and shortcomings in infection prevention preconditions. Results were categorised as low-, intermediate- and high risk, presented in an easy-to-read graphic risk spider-plot. This plot was given as feedback to management and healthcare workers of the NH. Results Large differences were found among most the variables in the different NH. Common shortcomings were the availability of infection control guidelines and the level of environmental cleaning. Most striking differences were observed in the prevalence of ESBL carriage, ranged from zero to 20.6% (p < 0.001). Conclusions The IRIS provided a rapid and easy to understand assessment of the infection control situation of the participating NH. The results can be used to improve the quality of infection control based on the specific needs of a NH but needs further validation in future studies. Repeated measurement can determine the effectiveness of the interventions. This makes the IRIS a useful tool for quality systems. PMID:25243067

Identification of factors to increase efficacy of telemedicine screening for diabetic retinopathy in endocrinology practices using the Intelligent Retinal Imaging System (IRIS) platform.

PubMed

Naik, Sapna; Wykoff, Charles C; Ou, William C; Stevenson, Jonathan; Gupta, Sunil; Shah, Ankoor R

2018-06-01

Diabetic retinopathy (DR) and diabetic macular edema (DME) can be evaluated using telemedicine systems, such as the Intelligent Retinal Imaging Systems (IRIS), in patients with Diabetes Mellitus (DM). In an endocrinology-based population utilizing IRIS we determine prevalence rates of DR and DME, and identify associated epidemiologic correlations. This is a multicenter, retrospective chart review using screening data from IRIS. Centers for Disease Control and Prevention (CDC) data on epidemiologic variables (by county) namely, prevalence of DM, incidence of DM, obesity, and time of physical inactivity, were compared against prevalence rates of DR found at screening. A total of 10,223 eyes of 5,242 patients with DM were imaged. DR and DME were noted in 1781 (33.98%) and 226 imaging studies (4.31%) respectively. The coefficient of determination was greatest for incidence of DM (R 2  = 0.92), followed by DM prevalence (R 2  = 0.79), obesity, (R 2  = 0.67), and physical inactivity (R 2  = 0.34). The presence of DR during screening varied significantly by county (p < 0.001). Screening in counties with a higher incidence of DM led to a higher prevalence of identified DR at time of screening. The current work suggests that telemedicine screening in areas known to have a higher incidence of DM may be worthwhile. Copyright © 2018 Elsevier B.V. All rights reserved.

Double hump sign in indentation gonioscopy is correlated with presence of plateau iris configuration regardless of patent iridotomy.

PubMed

Kiuchi, Yoshiaki; Kanamoto, Takashi; Nakamura, Takao

2009-02-01

A plateau iris is one of the clinical forms of angle closure glaucoma. In patients with a patent iridotomy, the double hump sign detected during indentation gonioscopy has been reported to indicate the existence of a plateau iris configuration. The purpose of this study was to determine whether the double hump sign is correlated with the presence of the plateau iris syndrome regardless of the patency of the iridotomy. Five women and 3 men without a patent iridotomy presented with narrow angles on gonioscopy and a double hump sign on indentation gonioscopy. Ultrasound biomicroscopy (UBM) imaging was performed to determine the etiology of the narrow angle and double hump sign, and to determine the appropriate treatment to prevent the progression of visual field damage. Ten patients with narrow angles and without a double hump sign were also examined by UBM to serve as a control group. All 8 patients who showed double hump sign had a short iris root, which was inserted anterior to the ciliary face, a typical anatomic appearance of a plateau iris. On the other hand, only 1 eye of 10 eyes in control group appeared to have a plateau iris. A double hump sign observed on indentation gonioscopy is strongly correlated with the presence of a plateau iris, and therefore a useful indicator of a plateau iris configuration regardless of the patency of a laser iridotomy. Thus, a plateau iris configuration can be detected without using a UBM in many cases.

Spectral Analysis Flare ribbons by NST and IRIS

NASA Astrophysics Data System (ADS)

Huang, Nengyi; Xu, Yan; Wang, Haimin; Jing, Ju

2017-08-01

As one of the most powerful phenomena of solar activities, flares have long been observed and studied extensively. Taking advantages of observing capabilities of modern solar telescopes and focal-plane instruments such as the Interface Region Imaging Spectrograph (IRIS) and the 1.6 m New Solar Telescope (NST) at Big Bear Solar observatory (BBSO), we are able to obtain high resolution imaging spectroscopic data in UV, visible and near-infrared (NIR) wavelengths. Here we present the spectral analysis of an M6.5 flare (SOL2015-06-22T18:23) which was well covered by the joint observation of IRIS and NST. In the visible wavelengths H-alpha and TiO, we can separate the flare ribbon into a very narrow leading front and faint trailing component, of which the former is characterized by the intense emission and significant Doppler signals. In the IRIS UV spectra, the ribbon front shows distinct properties, such as the line broadening, Doppler shifts and central reversal pattern, which are consistent with the visible observations. These characteristics suggest that the ribbon front to be the p

IRIS Toxicological Review of Thallium and Compounds ...

EPA Pesticide Factsheets

Thallium compounds are used in the semiconductor industry, the manufacture of optic lenses and low-melting glass, low-temperature thermometers, alloys, electronic devices, mercury lamps, fireworks, and imitation germs, and clinically as an imaging agent in the diagnosis of certain tumors. EPA's assessment of noncancer health effects and carcinogenic potential of thallium compounds was last prepared and added to the IRIS database between 1988 and 1990. The IRIS program is preparing an assessment that will incorporate current health effects information available for thallium and compounds, and current risk assessment methods. The IRIS assessment for thallium compounds will consist of a Toxicological Review and IRIS Summary. The Toxicological Review is a critical review of the physiochemical and toxicokinetic properties of a chemical, and its toxicity in humans and experimental systems. The assessment will present reference values for the noncancer effects of thallium compounds (RfD and Rfc), and a cancer assessment. The Toxicological Review and IRIS Summary have been subject to Agency review, Interagency review, and external scientific peer review. The final product will reflect the Agency opinion on the overall toxicity of thallium and compounds. EPA is undertaking an Integrated Risk Information System (IRIS) health assessment for thallium and compounds. IRIS is an EPA database containing Agency scientific positions on potential adverse human health effec

Appropriate Objective Functions for Quantifying Iris Mechanical Properties Using Inverse Finite Element Modeling.

PubMed

Pant, Anup D; Dorairaj, Syril K; Amini, Rouzbeh

2018-07-01

Quantifying the mechanical properties of the iris is important, as it provides insight into the pathophysiology of glaucoma. Recent ex vivo studies have shown that the mechanical properties of the iris are different in glaucomatous eyes as compared to normal ones. Notwithstanding the importance of the ex vivo studies, such measurements are severely limited for diagnosis and preclude development of treatment strategies. With the advent of detailed imaging modalities, it is possible to determine the in vivo mechanical properties using inverse finite element (FE) modeling. An inverse modeling approach requires an appropriate objective function for reliable estimation of parameters. In the case of the iris, numerous measurements such as iris chord length (CL) and iris concavity (CV) are made routinely in clinical practice. In this study, we have evaluated five different objective functions chosen based on the iris biometrics (in the presence and absence of clinical measurement errors) to determine the appropriate criterion for inverse modeling. Our results showed that in the absence of experimental measurement error, a combination of iris CL and CV can be used as the objective function. However, with the addition of measurement errors, the objective functions that employ a large number of local displacement values provide more reliable outcomes.

The HYSPIRI Decadal Survey Mission: Update on the Mission Concept and Science Objectives for Global Imaging Spectroscopy and Multi-Spectral Thermal Measurements

NASA Technical Reports Server (NTRS)

Green, Robert O.; Hook, Simon J.; Middleton, Elizabeth; Turner, Woody; Ungar, Stephen; Knox, Robert

2012-01-01

The NASA HyspIRI mission is planned to provide global solar reflected energy spectroscopic measurement of the terrestrial and shallow water regions of the Earth every 19 days will all measurements downlinked. In addition, HyspIRI will provide multi-spectral thermal measurements with a single band in the 4 micron region and seven bands in the 8 to 12 micron region with 5 day day/night coverage. A direct broadcast capability for measurement subsets is also planned. This HyspIRI mission is one of those designated in the 2007 National Research Council (NRC) Decadal Survey: Earth Science and Applications from Space. In the Decadal Survey, HyspIRI was recognized as relevant to a range of Earth science and science applications, including climate: "A hyperspectral sensor (e.g., FLORA) combined with a multispectral thermal sensor (e.g., SAVII) in low Earth orbit (LEO) is part of an integrated mission concept [described in Parts I and II] that is relevant to several panels, especially the climate variability panel." The HyspIRI science study group was formed in 2008 to evaluate and refine the mission concept. This group has developed a series of HyspIRI science objectives: (1) Climate: Ecosystem biochemistry, condition & feedback; spectral albedo; carbon/dust on snow/ice; biomass burning; evapotranspiration (2) Ecosystems: Global plant functional types, physiological condition, and biochemistry including agricultural lands (3) Fires: Fuel status, fire frequency, severity, emissions, and patterns of recovery globally (4) Coral reef and coastal habitats: Global composition and status (5) Volcanoes: Eruptions, emissions, regional and global impact (6) Geology and resources: Global distributions of surface mineral resources and improved understanding of geology and related hazards These objectives are achieved with the following measurement capabilities. The HyspIRI imaging spectrometer provides: full spectral coverage from 380 to 2500 at 10 nm sampling; 60 m spatial sampling with a 150 km swath; and fully downlinked coverage of the Earth's terrestrial and shallow water regions every 19 days to provide seasonal cloud-free coverage of the terrestrial surface. The HyspIRI Multi-Spectral Thermal instrument provides: 8 spectral bands from 4 to 12 microns; 60 m spatial sampling with a 600 km swath; and fully downlinked coverage of the Earth's terrestrial shallow water regions every 5 days (day/night) to provide nominally cloud-free monthly coverage. The HyspIRI mission also includes an on-board processing and direct broadcast capability, referred to as the Intelligent Payload Module (IPM), which will allow users with the appropriate antenna to download a subset of the HyspIRI data stream to a local ground station. These science and science application objectives are critical today and uniquely addressed by the combined imaging spectroscopy, thermal infrared measurements, and IPM direct broadcast capability of HyspIRI. Two key objectives are: (1) The global HyspIRI spectroscopic measurements of the terrestrial biosphere including vegetation composition and function to constrain and reduce the uncertainty in climate-carbon interactions and terrestrial biosphere feedback. (2) The global 8 band thermal measurements to provide improved constraint of fire related emissions. In this paper the current HyspIRI mission concept that has been reviewed and refined to its current level of maturity with a Data Products Symposium, Science Workshop and NASA HWorkshop is presented including traceability between the measurements and the science and science application objectives.

Mitochondria-targeted antioxidant MitoQ reduced renal damage caused by ischemia-reperfusion injury in rodent kidneys: Longitudinal observations of T2 -weighted imaging and dynamic contrast-enhanced MRI.

PubMed

Liu, Xiaoge; Murphy, Michael P; Xing, Wei; Wu, Huanhuan; Zhang, Rui; Sun, Haoran

2018-03-01

To investigate the effect of mitochondria-targeted antioxidant MitoQ in reducing the severity of renal ischemia-reperfusion injury (IRI) in rats using T 2 -weighted imaging and dynamic contrast-enhanced MRI (DCE-MRI). Ischemia-reperfusion injury was induced by temporarily clamping the left renal artery. Rats were pretreated with MitoQ or saline. The MRI examination was performed before and after IRI (days 2, 5, 7, and 14). The T 2 -weighted standardized signal intensity of the outer stripe of the outer medulla (OSOM) was measured. The unilateral renal clearance rate k cl was derived from DCE-MRI. Histopathology was evaluated after the final MRI examination. The standardized signal intensity of the OSOM on IRI kidneys with MitoQ were lower than those with saline on days 5 and 7 (P = 0.004, P < 0.001, respectively). K cl values of IRI kidneys with MitoQ were higher than those with saline at all time points (P = 0.002, P < 0.001, P = 0.001, P < 0.001). Histopathology showed that renal damage was the most predominant on the OSOM of IRI kidneys with saline, which was less obvious with MitoQ (P < 0.001). These findings demonstrate that MitoQ can reduce the severity of renal damage in rodent IRI models using T 2 -weighted imaging and DCE-MRI. Magn Reson Med 79:1559-1667, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Mitochondria‐targeted antioxidant MitoQ reduced renal damage caused by ischemia‐reperfusion injury in rodent kidneys: Longitudinal observations of T 2‐weighted imaging and dynamic contrast‐enhanced MRI

PubMed Central

Liu, Xiaoge; Murphy, Michael P.; Xing, Wei; Wu, Huanhuan; Zhang, Rui

2017-01-01

Purpose To investigate the effect of mitochondria‐targeted antioxidant MitoQ in reducing the severity of renal ischemia‐reperfusion injury (IRI) in rats using T2‐weighted imaging and dynamic contrast‐enhanced MRI (DCE‐MRI). Methods Ischemia‐reperfusion injury was induced by temporarily clamping the left renal artery. Rats were pretreated with MitoQ or saline. The MRI examination was performed before and after IRI (days 2, 5, 7, and 14). The T2‐weighted standardized signal intensity of the outer stripe of the outer medulla (OSOM) was measured. The unilateral renal clearance rate kcl was derived from DCE‐MRI. Histopathology was evaluated after the final MRI examination. Results The standardized signal intensity of the OSOM on IRI kidneys with MitoQ were lower than those with saline on days 5 and 7 (P = 0.004, P < 0.001, respectively). Kcl values of IRI kidneys with MitoQ were higher than those with saline at all time points (P = 0.002, P < 0.001, P = 0.001, P < 0.001). Histopathology showed that renal damage was the most predominant on the OSOM of IRI kidneys with saline, which was less obvious with MitoQ (P < 0.001). Conclusions These findings demonstrate that MitoQ can reduce the severity of renal damage in rodent IRI models using T2‐weighted imaging and DCE‐MRI. Magn Reson Med 79:1559–1667, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:28608403

Infrared interferometer spectrometer and radiometer (IRIS) instrument for Mariner/Jupiter/Saturn 1977 (MJS'77)

NASA Technical Reports Server (NTRS)

Vanous, D. D.

1974-01-01

The development and characteristics of the infrared interferometer spectrometer and radiometer (IRIS) instrument for use with the Mariner/Jupiter/Saturn space probe. The subjects discussed are: (1) the electronic design, (2) the opto-mechanical design, (3) reliability analysis, (4) quality control, and (5) program management.

Comparison of gonioscopy and anterior segment ocular coherence tomography in detecting angle closure in different quadrants of the anterior chamber angle.

PubMed

Sakata, Lisandro M; Lavanya, Raghavan; Friedman, David S; Aung, Han T; Gao, Hong; Kumar, Rajesh S; Foster, Paul J; Aung, Tin

2008-05-01

To compare the performance of gonioscopy and anterior segment (AS) optical coherence tomography (OCT) in detecting angle closure in the different quadrants of the anterior chamber angle (ACA). Cross-sectional observational study. Five hundred two consecutive subjects more than 50 years of age with no previous ophthalmic problems recruited from a community clinic in Singapore. All subjects underwent gonioscopy and AS OCT imaging in the dark. Using gonioscopy, the ACA was graded using the Scheie system by a single examiner masked to AS OCT findings. The ACA in a particular quadrant was classified as closed if the posterior trabecular meshwork could not be seen on gonioscopy. A closed ACA on AS OCT imaging was defined by the presence of any contact between the iris and angle wall anterior to the scleral spur. After excluding eyes with poor image quality, a total of 423 right eyes were included in the analysis. A closed angle in at least 1 quadrant was observed in 59% of the eyes by AS OCT and in 33% of the eyes by gonioscopy (P<0.001), with fair agreement between the two methods (kappa = 0.40). The frequency of closed angles by AS OCT and gonioscopy were 48% versus 29% superiorly, 43% versus 22% inferiorly, 18% versus 14% nasally, and 12% versus 20% temporally, respectively. Of the 119 of 1692 quadrants that were closed on gonioscopy but open on AS OCT, a steep iris profile was present in 61 (51%) of 119 quadrants on AS OCT, and of the 276 of 1692 quadrants that were open on gonioscopy but closed on AS OCT, 196 (71%) of 276 quadrants showed short iridoangle contact on AS OCT. The highest rates of closed angles on gonioscopy and AS OCT images were observed in the superior quadrant. Anterior segment OCT tended to detect more closed ACAs than gonioscopy, particularly in the superior and inferior quadrants. Variations in the iris profile and level of iridoangle contact also may explain some of the differences seen between gonioscopy and AS OCT.

Update On Ink Jet Proofing

NASA Astrophysics Data System (ADS)

Santos, Richard P.

1989-04-01

IRIS Graphics, Inc., is a new start-up company chartered to develop, manufacture, and market direct digital filmless color imaging systems. IRIS is pleased to have been the recipient of the Graphic Art Technologies Foundation INTERTEC '87 Award for innovative excellence. IRIS is extremely proud to have been given this honor. IRIS was incorporated in April 1984 and received its initial funding of approximately 1 million by September 1984. The first 2044 Beta unit was installed in August 1985, and the first 2044 sales were made in December 1985 to R. R. Donnelley, the largest printer in the United States, and to G. S. Litho, the largest U.S. color separation house. In May 1986, IRIS received an additional 3 million in its second round of financing. A smaller version of the 2044, the 2024 was introduced at Lasers In Graphics in September 1986. IRIS achieved additional financing in July 1987 and completed the introduction of the new breakthrough Series 3000 again at Lasers In Graphics in September 1987 in Orlando, Florida. IRIS occupies 20,000 square feet at its new location in Bedford, Massachusetts, which located off of Route 128 in the high technology area near Boston.

In vivo label-free photoacoustic microscopy of the anterior segment of the mouse eye

NASA Astrophysics Data System (ADS)

Rao, Bin; Hu, Song; Li, Li; Maslov, Konstantin; Wang, Lihong V.

2010-02-01

Both iris fluorescein angiography (IFA) and indocyanine green angiography (ICGA) provide ophthalmologists imaging tools in studying the microvasculature structure and hemodynamics of the anterior segment of the eye in normal and diseased status. However, a non-invasive, endogenous imaging modality is preferable for the monitoring of hemodynamics of the iris microvasculature. We investigated the in vivo, label-free ocular anterior segment imaging with photo-acoustic microscopy (PAM) in mouse eyes. We demonstrated the unique advantage of endogenous contrast that is not available in both IFA and ICGA. The laser radiation was maintained within the ANSI laser safety limit. The in vivo, label-free nature of our imaging technology has the potential for ophthalmic applications.

KSC-2013-3005

NASA Image and Video Library

2013-06-27

VANDENBERG AFB, Calif. – An Orbital Sciences L-1011 carrier aircraft flies over the Pacific Ocean off the California coast on a mission to launch NASA's IRIS spacecraft into low-Earth orbit. IRIS, short for Interface Region Imaging Spectrograph, was launched aboard an Orbital Sciences Pegasus XL rocket released from the bottom of the L-1011.Photo credit: NASA/Lori Losey

KSC-2013-3003

NASA Image and Video Library

2013-06-27

VANDENBERG AFB, Calif. – An Orbital Sciences L-1011 carrier aircraft flies over the Pacific Ocean off the California coast on a mission to launch NASA's IRIS spacecraft into low-Earth orbit. IRIS, short for Interface Region Imaging Spectrograph, was launched aboard an Orbital Sciences Pegasus XL rocket released from the bottom of the L-1011.Photo credit: NASA/Lori Losey

KSC-2013-3004

NASA Image and Video Library

2013-06-27

VANDENBERG AFB, Calif. – An Orbital Sciences L-1011 carrier aircraft flies over the Pacific Ocean off the California coast on a mission to launch NASA's IRIS spacecraft into low-Earth orbit. IRIS, short for Interface Region Imaging Spectrograph, was launched aboard an Orbital Sciences Pegasus XL rocket released from the bottom of the L-1011.Photo credit: NASA/Lori Losey

Selective atrophy in the lateral geniculate nucleus associated with iris coloboma in cat.

PubMed

Richards, W

1977-01-01

A kitten with a unilateral, congenital coloboma of the iris was raised in a normal environment and sacrificed at 6 monthlicted eye was seen in Nissl-stained sections taken through the lateral geniculate. The result suggests that image degradation is more important than luminance reduction in causing selective changes in the visual pathway.

UV and X-ray Evolution of AR12230 as Observed with IRIS and FOXSI-II

NASA Astrophysics Data System (ADS)

Ryan, Daniel; Christe, Steven; Glesener, Lindsay; Vievering, Julie; Krucker, Sam; Ishikawa, Shin-Nosuke

2017-08-01

We present a multi-spectral and spatio-temporal analysis of AR12230 using both UV and X-ray spectroscopic imaging obtained as part of a coordinated observing campaign on 11 December 2014. The campaign involved IRIS (Interface Region Imaging Spectrometer) -- which provides both UV imaging and slit spectrograph observations of optically thick chromospheric and transition region emission -- and FOXSI-II (Focusing Optics X-ray Solar Imager) -- the second in a series of sounding rocket flights which combines grazing incidence direct focusing optics to produce solar X-ray spectroscopic imaging in the range 4-15keV. The active region exhibits a prolonged compact brightening in the IRIS 1330 A and 1400 A slit-jaw channels near the center of the active region throughout the duration of the observations. In the early phase of the observations FOXSI-II shows an X-ray source approximately 20x20 arcsec centered at the same location. The X-ray spectra show the presence of hot (~8 MK) thermal plasma and is suggestive of the presence of non-thermal electrons.. Later, two additional transient, spatially extended, simultaneous brightenings are observed, one of which was captured by the IRIS slit spectrograph. We combine these observations to explore the evolution and topology of the active region. Hydrodynamic modeling of the chromosphere is used to place a limit on the amount of non-thermal electrons required to produce the observed UV emission. This result is then compared to the limit inferred from the FOXSI-II X-ray spectra. Thus, we explore the role of non-thermal electrons and hydrodynamics in the energization and evolution of plasma in active regions.

NASA's Best-Observed X-Class Flare of All Time

NASA Image and Video Library

2014-05-07

Like almost all solar observatories, NASA's IRIS can provide images of different layers of the sun's atmosphere, which together create a whole picture of what's happening. This image shows light at a wavelength of 1400 Angstrom, which highlights material some 650 miles above the sun's surface. The vertical line in the middle shows the slit for IRIS's spectrograph, which can separate light into its many wavelengths to provide even more information about the temperature and velocity of material during a flare. Credit: NASA/IRIS/Goddard Space Flight Center -- On March 29, 2014 the sun released an X-class flare. It was observed by NASA's Interface Region Imaging Spectrograph, or IRIS; NASA's Solar Dynamics Observatory, or SDO; NASA's Reuven Ramaty High Energy Solar Spectroscopic Imager, or RHESSI; the Japanese Aerospace Exploration Agency's Hinode; and the National Solar Observatory's Dunn Solar Telescope located at Sacramento Peak in New Mexico. To have a record of such an intense flare from so many observatories is unprecedented. Such research can help scientists better understand what catalyst sets off these large explosions on the sun. Perhaps we may even some day be able to predict their onset and forewarn of the radio blackouts solar flares can cause near Earth - blackouts that can interfere with airplane, ship and military communications. Read more: 1.usa.gov/1kMDQbO Join our Google+ Hangout on May 8 at 2:30pm EST: go.nasa.gov/1mwbBEZ Credit: NASA Goddard NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Comparison of Hyperspectral and Multispectral Satellites for Discriminating Land Cover in Northern California

NASA Astrophysics Data System (ADS)

Clark, M. L.; Kilham, N. E.

2015-12-01

Land-cover maps are important science products needed for natural resource and ecosystem service management, biodiversity conservation planning, and assessing human-induced and natural drivers of land change. Most land-cover maps at regional to global scales are produced with remote sensing techniques applied to multispectral satellite imagery with 30-500 m pixel sizes (e.g., Landsat, MODIS). Hyperspectral, or imaging spectrometer, imagery measuring the visible to shortwave infrared regions (VSWIR) of the spectrum have shown impressive capacity to map plant species and coarser land-cover associations, yet techniques have not been widely tested at regional and greater spatial scales. The Hyperspectral Infrared Imager (HyspIRI) mission is a VSWIR hyperspectral and thermal satellite being considered for development by NASA. The goal of this study was to assess multi-temporal, HyspIRI-like satellite imagery for improved land cover mapping relative to multispectral satellites. We mapped FAO Land Cover Classification System (LCCS) classes over 22,500 km2 in the San Francisco Bay Area, California using 30-m HyspIRI, Landsat 8 and Sentinel-2 imagery simulated from data acquired by NASA's AVIRIS airborne sensor. Random Forests (RF) and Multiple-Endmember Spectral Mixture Analysis (MESMA) classifiers were applied to the simulated images and accuracies were compared to those from real Landsat 8 images. The RF classifier was superior to MESMA, and multi-temporal data yielded higher accuracy than summer-only data. With RF, hyperspectral data had overall accuracy of 72.2% and 85.1% with full 20-class and reduced 12-class schemes, respectively. Multispectral imagery had lower accuracy. For example, simulated and real Landsat data had 7.5% and 4.6% lower accuracy than HyspIRI data with 12 classes, respectively. In summary, our results indicate increased mapping accuracy using HyspIRI multi-temporal imagery, particularly in discriminating different natural vegetation types, such as spectrally-mixed woodlands and forests.

The Hyperspectral Infrared Imager (HyspIRI) and Global Observations of Tidal Wetlands

NASA Astrophysics Data System (ADS)

Turpie, K. R.; Klemas, V. V.; Byrd, K. B.; Kelly, M.; Jo, Y. H.

2016-02-01

HyspIRI mission will employ a high-spectral resolution VSWIR spectrometer, with a 30 m spatial resolution and swath width equal to Landsat legacy instruments. The spectrometer is expected to have a signal-to-noise (SNR) ratio comparable to or better than the Hyperspectral Imager of the Coastal Ocean (HICO). The mission will also provide an imaging radiometer with eight thermal bands at 60m resolution 600 km swath width. HyspIRI will offer new and unique opportunities to globally study ecosystems where land meets sea. In particular, the mission will be a boon to observations of tidal wetlands, which are highly productive and act as critical habitat for a wide variety of plants, fish, shellfish, and other wildlife. These ecotones between aquatic and terrestrial environments also provide protection from storm damage, run-off filtering, and recharge of aquifers. Many wetlands along coasts have been exposed to stress-inducing alterations globally, including dredge and fill operations, hydrologic modifications, pollutants, impoundments, fragmentation by roads/ditches, and sea level rise. For wetland protection and sensible coastal development, there is a need to monitor these ecosystems at global and regional scales. We will describe how the HyspIRI hyperspectral and thermal infrared sensors can be used to study and map key ecological properties of tidal salt and brackish marshes and mangroves, and perhaps other major wetland types, including freshwater marshes and wooded/shrub wetlands.

Reconstruction of a helical prominence in 3D from IRIS spectra and images

NASA Astrophysics Data System (ADS)

Schmieder, B.; Zapiór, M.; López Ariste, A.; Levens, P.; Labrosse, N.; Gravet, R.

2017-10-01

Context. Movies of prominences obtained by space instruments e.g. the Solar Optical Telescope (SOT) aboard the Hinode satellite and the Interface Region Imaging Spectrograph (IRIS) with high temporal and spatial resolution revealed the tremendous dynamical nature of prominences. Knots of plasma belonging to prominences appear to travel along both vertical and horizontal thread-like loops, with highly dynamical nature. Aims: The aim of the paper is to reconstruct the 3D shape of a helical prominence observed over two and a half hours by IRIS. Methods: From the IRIS Mg II k spectra we compute Doppler shifts of the plasma inside the prominence and from the slit-jaw images (SJI) we derive the transverse field in the plane of the sky. Finally we obtain the velocity vector field of the knots in 3D. Results.We reconstruct the real trajectories of nine knots travelling along ellipses. Conclusions: The spiral-like structure of the prominence observed in the plane of the sky is mainly due to the projection effect of long arches of threads (up to 8 × 104 km). Knots run along more or less horizontal threads with velocities reaching 65 km s-1. The dominant driving force is the gas pressure. Movies associated to Figs. 1, 9, 10, and 13 are available at http://www.aanda.org

Propagating Disturbances in the Solar Corona and Spicular Connection

NASA Astrophysics Data System (ADS)

Samanta, Tanmoy; Pant, Vaibhav; Banerjee, Dipankar

2015-12-01

Spicules are small, hairy-like structures seen at the solar limb, mainly at chromospheric and transition region lines. They generally live for 3-10 minutes. We study these spicules in a south polar region of the Sun with coordinated observations using the Interface Region Imaging Spectrograph (IRIS) and the Atmospheric Imaging Assembly (AIA) instruments on board the Solar Dynamics Observatory. Propagating disturbances (PDs) are observed everywhere in the polar off-limb regions of the Sun at coronal heights. From these simultaneous observations, we show that the spicules and the PDs may have originated through a common process. From spacetime maps, we find that the start of the trajectory of PDs is almost cotemporal with the time of the rise of the spicular envelope as seen by IRIS slit-jaw images at 2796 and 1400 Å. During the return of spicular material, brightenings are seen in AIA 171 and 193 Å images. The quasi-periodic nature of the spicular activity, as revealed by the IRIS spectral image sequences, and its relation to coronal PDs, as recorded by the coronal AIA channels, suggest that they share a common origin. We propose that reconnection-like processes generate the spicules and waves simultaneously. The waves escape while the cool spicular material falls back.

Iris biometric system design using multispectral imaging

NASA Astrophysics Data System (ADS)

Widhianto, Benedictus Yohanes Bagus Y. B.; Nasution, Aulia M. T.

2016-11-01

An identity recognition system is a vital component that cannot be separated from life, iris biometric is one of the biometric that has the best accuracy reaching 99%. Usually, iris biometric systems use infrared spectrum lighting to reduce discomfort caused by radiation when the eye is given direct light, while the eumelamin that is forming the iris has the most flourescent radiation when given a spectrum of visible light. This research will be conducted by detecting iris wavelengths of 850 nm, 560 nm, and 590 nm, where the detection algorithm will be using Daugman algorithm by using a Gabor wavelet extraction feature, and matching feature using a Hamming distance. Results generated will be analyzed to identify how much differences there are, and to improve the accuracy of the multispectral biometric system and as a detector of the authenticity of the iris. The results obtained from the analysis of wavelengths 850 nm, 560 nm, and 590 nm respectively has an accuracy of 99,35 , 97,5 , 64,5 with a matching score of 0,26 , 0,23 , 0,37.

IRIS Burst Spectra Co-spatial to a Quiet-Sun Ellerman-like Brightening

NASA Astrophysics Data System (ADS)

Nelson, C. J.; Freij, N.; Reid, A.; Oliver, R.; Mathioudakis, M.; Erdélyi, R.

2017-08-01

Ellerman bombs (EBs) have been widely studied over the past two decades; however, only recently have the counterparts of these events been observed in the quiet-Sun. The aim of this article is to further understand small-scale quiet-Sun Ellerman-like brightenings (QSEBs) through research into their spectral signatures, including investigating whether the hot signatures associated with some EBs are also visible co-spatial to any QSEBs. We combine Hα and Ca II 8542 Å line scans at the solar limb with spectral and imaging data sampled by the Interface Region Imaging Spectrograph (IRIS). Twenty-one QSEBs were identified with average lifetimes, lengths, and widths measured to be around 120 s, 0.″63, and 0.″35, respectively. Three of these QSEBs displayed clear repetitive flaring through their lifetimes, comparable to the behavior of EBs in active regions. Two QSEBs in this sample occurred co-spatial to increased emission in SDO/AIA 1600 Å and IRIS slit-jaw imager 1400 Å data; however, these intensity increases were smaller than those reported co-spatially with EBs. One QSEB was also sampled by the IRIS slit during its lifetime, displaying increases in intensity in the Si IV 1393 Å and Si IV 1403 Å cores, as well as the C II and Mg II line wings, analogous to IRIS bursts (IBs). Using RADYN simulations, we are unable to reproduce the observed QSEB Hα and Ca II 8542 Å line profiles, leaving the question of the temperature stratification of QSEBs open. Our results imply that some QSEBs could be heated to transition region temperatures, suggesting that IB profiles should be observed throughout the quiet-Sun.

Spectroscopic photoacoustics for assessing ischemic kidney damage

NASA Astrophysics Data System (ADS)

Berndl, Elizabeth S. L.; He, Xiaolin; Yuen, Darren A.; Kolios, Michael C.

2018-02-01

Ischemic reperfusion injuries (IRIs) are caused by return of blood to a tissue or organ after a period without oxygen or nutrients. Damage in the microvasculature causes an inflammatory response and heterogeneous scarring, which is associated with an increase in collagen in the extracellular matrix. Although most often associated with heart attacks and strokes, IRI also occurs when blood reperfuses a transplanted organ. Currently, monitoring for IRI is limited to biopsies, which are invasive and sample a limited area. In this work, we explored photoacoustic (PA) biomarkers of scarring. IRI events were induced in mice (n=2) by clamping the left renal artery, then re-establishing flow. At 53 days post-surgery, kidneys were saline perfused and cut in half laterally. One half was immediately imaged with a VevoX system (Fujifilm-VisualSonics, Toronto) in two near infrared ranges - 680 to 970 nm (NIR), and 1200 to 1350 nm (NIR II). The other half was decellularized and then imaged at NIR and NIR II. Regions of interest were manually identified and analyzed for each kidney. For both cellularized and decellularized samples, the PA signal ratio based on irradiation wavelengths of 715:930 nm was higher in damaged kidneys than for undamaged kidneys (p < 0.0001 for both). Damaged kidneys had ROIs with spectra indicating the presence of collagen in the NIR II range, while healthy kidneys did not. Collagen rich spectra were more apparent in decellularized kidneys, suggesting that in the cellularized samples, other components may be contributing to the signal. PA imaging using spectral ratios associated with collagen signatures may provide a non-invasive tool to determine areas of tissue damage due to IRIs.

IRIS Burst Spectra Co-spatial to a Quiet-Sun Ellerman-like Brightening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, C. J.; Erdélyi, R.; Freij, N.

Ellerman bombs (EBs) have been widely studied over the past two decades; however, only recently have the counterparts of these events been observed in the quiet-Sun. The aim of this article is to further understand small-scale quiet-Sun Ellerman-like brightenings (QSEBs) through research into their spectral signatures, including investigating whether the hot signatures associated with some EBs are also visible co-spatial to any QSEBs. We combine H α and Ca ii 8542 Å line scans at the solar limb with spectral and imaging data sampled by the Interface Region Imaging Spectrograph ( IRIS ). Twenty-one QSEBs were identified with average lifetimes,more » lengths, and widths measured to be around 120 s, 0.″63, and 0.″35, respectively. Three of these QSEBs displayed clear repetitive flaring through their lifetimes, comparable to the behavior of EBs in active regions. Two QSEBs in this sample occurred co-spatial to increased emission in SDO /AIA 1600 Å and IRIS slit-jaw imager 1400 Å data; however, these intensity increases were smaller than those reported co-spatially with EBs. One QSEB was also sampled by the IRIS slit during its lifetime, displaying increases in intensity in the Si iv 1393 Å and Si iv 1403 Å cores, as well as the C ii and Mg ii line wings, analogous to IRIS bursts (IBs). Using RADYN simulations, we are unable to reproduce the observed QSEB H α and Ca ii 8542 Å line profiles, leaving the question of the temperature stratification of QSEBs open. Our results imply that some QSEBs could be heated to transition region temperatures, suggesting that IB profiles should be observed throughout the quiet-Sun.« less

Measurement of the temperature increase in the porcine cadaver iris during direct illumination by femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Sun, Hui; Kurtz, Ronald M.; Juhasz, Tibor

2010-02-01

Multiple femtosecond lasers have now been cleared for use for ophthalmic surgery, including for creation of corneal flaps in LASIK surgery. Preliminary measurements indicated that during typical surgical use, 50-60% of laser energy may pass beyond the cornea with potential effects on the iris. To further evaluate iris laser exposure during femtosecond corneal surgery, we measured the temperature increase in porcine cadaver iris in situ during direct illumination by the iFS Advanced Femtoosecond Laser (AMO Inc. Santa Ana, CA) with an infrared thermal imaging camera. To replicate the illumination geometry of the eye during the surgery, an excised porcine cadaver iris was placed 1.5 mm from the flat glass contact lens. The temperature field was observed in twenty cadaver iris at laser pulse energy levels ranging from 1 to 2 μJ (corresponding approximately to surgical energies of 2 to 4 μJ per pulse). Temperature increases up to 2.3 °C (corresponding to 2 μJ per pulse and 24 second procedure time) were observed in the cadaver iris with little variation in temperature profiles between specimens for the same laser energy illumination. For laser pulse energy and procedure time characteristic to the iFS Advanced Femtoosecond Laser the temperature increase was measured to be 1.2 °C. Our studies suggest that the magnitude of iris heating that occurs during such femtosecond laser corneal surgery is small and does not present a safety hazard to the iris.

A new method for generating an invariant iris private key based on the fuzzy vault system.

PubMed

Lee, Youn Joo; Park, Kang Ryoung; Lee, Sung Joo; Bae, Kwanghyuk; Kim, Jaihie

2008-10-01

Cryptographic systems have been widely used in many information security applications. One main challenge that these systems have faced has been how to protect private keys from attackers. Recently, biometric cryptosystems have been introduced as a reliable way of concealing private keys by using biometric data. A fuzzy vault refers to a biometric cryptosystem that can be used to effectively protect private keys and to release them only when legitimate users enter their biometric data. In biometric systems, a critical problem is storing biometric templates in a database. However, fuzzy vault systems do not need to directly store these templates since they are combined with private keys by using cryptography. Previous fuzzy vault systems were designed by using fingerprint, face, and so on. However, there has been no attempt to implement a fuzzy vault system that used an iris. In biometric applications, it is widely known that an iris can discriminate between persons better than other biometric modalities. In this paper, we propose a reliable fuzzy vault system based on local iris features. We extracted multiple iris features from multiple local regions in a given iris image, and the exact values of the unordered set were then produced using the clustering method. To align the iris templates with the new input iris data, a shift-matching technique was applied. Experimental results showed that 128-bit private keys were securely and robustly generated by using any given iris data without requiring prealignment.

Analysis of Inter-Moss Loops in the Solar Region with IRIS and SDO AIA: Automatic Event Detection and Characterization

NASA Technical Reports Server (NTRS)

Fayock, Brian; Winebarger, Amy; De Pontieu, Bart; Alexander, Caroline

2016-01-01

The Interface Region Imaging Spectrograph (IRIS), launched in the summer of 2013, is designed specifically to observe and investigate the transition region and adjacent layers of the solar atmosphere, obtaining images in high spatial, temporal, and spectral resolution. Our particular work is focused on the evolution of inter-moss loops, which have been detected in the lower corona by the Atmospheric Imaging Assembly (AIA) and the High-Resolution Coronal Imager (Hi- C), but are known to have foot points below the transition region. With the high-resolution capabilities of IRIS and its Si IV pass band, which measures activity in the upper chromosphere, we can study these magnetic loops in detail and compare their characteristic length and time scales to those obtained from several AIA image sets, particularly the 171, 193, and 211 pass bands. By comparing the results between these four data sets, one can potentially establish a measure of the ionization equilibrium for the location in question. To explore this idea, we found a large, sit-and-stare observation within the IRIS database that fit our specifications. This data set contained a number of well-defined inter-moss loops (by visual inspection) with a cadence less than or equal to that of AIA (approximately 12 seconds). This particular data set was recorded on October 23, 2013 at 07:09:30, lasting for 3219 seconds with a field of view of 120.6 by 128.1 arcseconds, centered on -53.9 by 59.1 arcseconds from disk center. For ease of comparison, the AIA data has been interpolated to match the IRIS cadence and resolution. In the main portion of the poster, we demonstrate the detection of events, the information collected, and the immediate results to the right, showing the progress of an event with green as the start, blue as the peak, and red as the end. Below here, we demonstrate how pixels are combined to form groups. The 3D results are shown to the right

Analysis of Inter-Moss Loops in the Solar Region with IRIS and SDO AIA: Automatic Event Detection and Characterization

NASA Technical Reports Server (NTRS)

Fayock, Brian; Winebarger, Amy; De Pontieu, Bart

2014-01-01

The Interface Region Imaging Spectrograph (IRIS), launched in the summer of 2013, is designed specifically to observe and investigate the transition region and adjacent layers of the solar atmosphere, obtaining images in high spatial, temporal, and spectral resolution. Our particular work is focused on the evolution of inter-moss loops, which have been detected in the lower corona by the Atmospheric Imaging Assembly (AIA) and the High-Resolution Coronal Imager (Hi- C), but are known to have foot points below the transition region. With the high-resolution capabilities of IRIS and its Si IV pass band, which measures activity in the upper chromosphere, we can study these magnetic loops in detail and compare their characteristic length and time scales to those obtained from several AIA image sets, particularly the 171, 193, and 211 pass bands. By comparing the results between these four data sets, one can potentially establish a measure of the ionization equilibrium for the location in question. To explore this idea, we found a large, sit-and-stare observation within the IRIS database that fit our specifications. This data set contained a number of well-defined inter-moss loops (by visual inspection) with a cadence less than or equal to that of AIA (approximately 12 seconds). This particular data set was recorded on October 23, 2013 at 07:09:30, lasting for 3219 seconds with a field of view of 120.6 by 128.1 arcseconds, centered on -53.9 by 59.1 arcseconds from disk center. For ease of comparison, the AIA data has been interpolated to match the IRIS cadence and resolution. In the main portion of the poster, we demonstrate the detection of events, the information collected, and the immediate results to the right, showing the progress of an event with green as the start, blue as the peak, and red as the end. Below here, we demonstrate how pixels are combined to form groups. The 3D results are shown to the right.

From the Ground Up: Building an Earth Science Satellite (HyspIRI Hawaii, Part 5)

NASA Image and Video Library

2017-05-01

Scientists from NASA and University of Hawaii, in partnership the U.S. Naval Research Laboratory, teamed up in February 2017 to study the health of coral reefs located around the Hawaiian Islands for the Hyperspectral InfraRed Imager (HyspIRI) airborne preparatory mission. Research divers and an autonomous kayak monitored coral color signatures from the ocean floor and surface, while NASA’s high-altitude ER-2 collected images of the same areas from a height of 70,000 ft. The data from these sources are being combined to better understand how coral reef ecosystems are responding to stressful conditions like warming ocean temperatures and water acidification. Data from this mission will potentially help develop a NASA satellite to study natural hazards and ecosystems all over the world. Learn more about the HyspIRI airborne mission here: https://www.jpl.nasa.gov/news/news.php?feature=6793

Interferometric Reflectance Imaging Sensor (IRIS)—A Platform Technology for Multiplexed Diagnostics and Digital Detection

PubMed Central

Avci, Oguzhan; Lortlar Ünlü, Nese; Yalçın Özkumur, Ayça; Ünlü, M. Selim

2015-01-01

Over the last decade, the growing need in disease diagnostics has stimulated rapid development of new technologies with unprecedented capabilities. Recent emerging infectious diseases and epidemics have revealed the shortcomings of existing diagnostics tools, and the necessity for further improvements. Optical biosensors can lay the foundations for future generation diagnostics by providing means to detect biomarkers in a highly sensitive, specific, quantitative and multiplexed fashion. Here, we review an optical sensing technology, Interferometric Reflectance Imaging Sensor (IRIS), and the relevant features of this multifunctional platform for quantitative, label-free and dynamic detection. We discuss two distinct modalities for IRIS: (i) low-magnification (ensemble biomolecular mass measurements) and (ii) high-magnification (digital detection of individual nanoparticles) along with their applications, including label-free detection of multiplexed protein chips, measurement of single nucleotide polymorphism, quantification of transcription factor DNA binding, and high sensitivity digital sensing and characterization of nanoparticles and viruses. PMID:26205273

High frequency ultrasound imaging in pupillary block glaucoma.

PubMed Central

Aslanides, I M; Libre, P E; Silverman, R H; Reinstein, D Z; Lazzaro, D R; Rondeau, M J; Harmon, G K; Coleman, D J

1995-01-01

BACKGROUND--The diagnosis of pupillary block glaucoma requires sufficient clarity of the ocular media. This is particularly important for assessment of both the presence and patency of an iridotomy, and the determination of central anterior chamber depth. METHODS--High frequency ultrasonography was used in three patients with suspected pupillary block to determine iris configuration, posterior chamber volume, and ciliary body conformation. RESULTS--All patients demonstrated high frequency ultrasonographic findings consistent with pupillary block: iris bombé, a formed posterior chamber, and a lack of anterior rotation of the ciliary processes. CONCLUSION--High frequency ultrasound imaging appears to be a valuable adjunct in making or corroborating the diagnosis of pupillary block glaucoma. Images PMID:8534666

Onboard Autonomy and Ground Operations Automation for the Intelligent Payload Experiment (IPEX) CubeSat Mission

NASA Technical Reports Server (NTRS)

Chien, Steve; Doubleday, Joshua; Ortega, Kevin; Tran, Daniel; Bellardo, John; Williams, Austin; Piug-Suari, Jordi; Crum, Gary; Flatley, Thomas

2012-01-01

The Intelligent Payload Experiment (IPEX) is a cubesat manifested for launch in October 2013 that will flight validate autonomous operations for onboard instrument processing and product generation for the Intelligent Payload Module (IPM) of the Hyperspectral Infra-red Imager (HyspIRI) mission concept. We first describe the ground and flight operations concept for HyspIRI IPM operations. We then describe the ground and flight operations concept for the IPEX mission and how that will validate HyspIRI IPM operations. We then detail the current status of the mission and outline the schedule for future development.

Synegies Between Visible/Near-Infrared Imaging Spectrometry and the Thermal Infrared in an Urban Environment: An Evaluation of the Hyperspectral Infrared Imager (HYSPIRI) Mission

NASA Technical Reports Server (NTRS)

Roberts, Dar A.; Quattrochi, Dale A.; Hulley, Glynn C.; Hook, Simon J.; Green, Robert O.

2012-01-01

A majority of the human population lives in urban areas and as such, the quality of urban environments is becoming increasingly important to the human population. Furthermore, these areas are major sources of environmental contaminants and sinks of energy and materials. Remote sensing provides an improved understanding of urban areas and their impacts by mapping urban extent, urban composition (vegetation and impervious cover fractions), and urban radiation balance through measures of albedo, emissivity and land surface temperature (LST). Recently, the National Research Council (NRC) completed an assessment of remote sensing needs for the next decade (NRC, 2007), proposing several missions suitable for urban studies, including a visible, near-infrared and shortwave infrared (VSWIR) imaging spectrometer and a multispectral thermal infrared (TIR) instrument called the Hyperspectral Infrared Imagery (HyspIRI). In this talk, we introduce the HyspIRI mission, focusing on potential synergies between VSWIR and TIR data in an urban area. We evaluate potential synergies using an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and MODIS-ASTER (MASTER) image pair acquired over Santa Barbara, United States. AVIRIS data were analyzed at their native spatial resolutions (7.5m VSWIR and 15m TIR), and aggregated 60 m spatial resolution similar to HyspIRI. Surface reflectance was calculated using ACORN and a ground reflectance target to remove atmospheric and sensor artifacts. MASTER data were processed to generate estimates of spectral emissivity and LST using Modtran radiative transfer code and the ASTER Temperature Emissivity Separation algorithm. A spectral library of common urban materials, including urban vegetation, roofs and roads was assembled from combined AVIRIS and field-measured reflectance spectra. LST and emissivity were also retrieved from MASTER and reflectance/emissivity spectra for a subset of urban materials were retrieved from co-located MASTER and AVIRIS pixels. Fractions of Impervious, Soil, Green Vegetation (GV) and Non-photosynthetic Vegetation (NPV), were estimated using Multiple Endmember Spectral Mixture Analysis (MESMA) applied to AVIRIS data at 7.5, 15 and 60 m spatial scales. Surface energy parameters, including albedo, vegetation cover fraction, broadband emissivity and LST were also determined for urban and natural land-cover classes in the region. Fractions were validated using 1m digital photography.

How Big Data Informs Us About Cataract Surgery: The LXXII Edward Jackson Memorial Lecture.

PubMed

Coleman, Anne Louise

2015-12-01

To characterize the role of Big Data in evaluating quality of care in ophthalmology, to highlight opportunities for studying quality improvement using data available in the American Academy of Ophthalmology Intelligent Research in Sight (IRIS) Registry, and to show how Big Data informs us about rare events such as endophthalmitis after cataract surgery. Review of published studies, analysis of public-use Medicare claims files from 2010 to 2013, and analysis of IRIS Registry from 2013 to 2014. Statistical analysis of observational data. The overall rate of endophthalmitis after cataract surgery was 0.14% in 216 703 individuals in the Medicare database. In the IRIS Registry the endophthalmitis rate after cataract surgery was 0.08% among 511 182 individuals. Endophthalmitis rates tended to be higher in eyes with combined cataract surgery and anterior vitrectomy (P = .051), although only 0.08% of eyes had this combined procedure. Visual acuity (VA) in the IRIS Registry in eyes with and without postoperative endophthalmitis measured 1-7 days postoperatively were logMAR 0.58 (standard deviation [SD]: 0.84) (approximately Snellen acuity of 20/80) and logMAR 0.31 (SD: 0.34) (approximately Snellen acuity of 20/40), respectively. In 33 547 eyes with postoperative VA after cataract surgery, 18.3% had 1-month-postoperative VA worse than 20/40. Big Data drawing on Medicare claims and IRIS Registry records can help identify additional areas for quality improvement, such as in the 18.3% of eyes in the IRIS Registry having 1-month-postoperative VA worse than 20/40. The ability to track patient outcomes in Big Data sets provides opportunities for further research on rare complications such as postoperative endophthalmitis and outcomes from uncommon procedures such as cataract surgery combined with anterior vitrectomy. But privacy and data-security concerns associated with Big Data should not be taken lightly. Copyright © 2015 Elsevier Inc. All rights reserved.

ELLERMAN BOMBS AT HIGH RESOLUTION. III. SIMULTANEOUS OBSERVATIONS WITH IRIS AND SST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vissers, G. J. M.; Voort, L. H. M. Rouppe van der; Rutten, R. J.

Ellerman bombs (EBs) are transient brightenings of the extended wings of the solar Balmer lines in emerging active regions. We describe their properties in the ultraviolet lines sampled by the Interface Region Imaging Spectrograph (IRIS), using simultaneous imaging spectroscopy in Hα with the Swedish 1-m Solar Telescope (SST) and ultraviolet images from the Solar Dynamics Observatory for Ellerman bomb detection and identification. We select multiple co-observed EBs for detailed analysis. The IRIS spectra strengthen the view that EBs mark reconnection between bipolar kilogauss fluxtubes with the reconnection and the resulting bi-directional jet located within the solar photosphere and shielded bymore » overlying chromospheric fibrils in the cores of strong lines. The spectra suggest that the reconnecting photospheric gas underneath is heated sufficiently to momentarily reach stages of ionization normally assigned to the transition region and the corona. We also analyze similar outburst phenomena that we classify as small flaring arch filaments and ascribe to reconnection at a higher location. They have different morphologies and produce hot arches in million-Kelvin diagnostics.« less

Limbal Stem Cell Preservation During Proton Beam Irradiation for Diffuse Iris Melanoma.

PubMed

Singh, Arun D; Dupps, William J; Biscotti, Charles V; Suh, John H; Lathrop, Kira L; Nairn, John P; Shih, Helen

2017-01-01

To report the outcome after limbal stem cell preservation during proton beam irradiation for diffuse iris melanoma. This is a single-case report of diffuse iris melanoma that was managed with proton beam radiation (53 Gy), wherein preemptively harvested superior and inferior limbal stem cells before radiation were replaced after irradiation. Regeneration of the palisades of Vogt and the limbal stem cells was documented by an optical coherence tomography-based imaging protocol. At 24 months after radiation therapy, best-corrected visual acuity was 20/25. The cornea was clear without evidence of limbal stem cell dysfunction. Clinical examination (including gonioscopy and ultrasound biomicroscopy [UBM]) was indicative of local control, and systemic surveillance was negative for metastatic disease. At posttransplant (21 months), there were more palisade structures visible in both anterior and posterior regions of the superior and inferior limbus, and the linear presentation of the inferior palisades appears to have regenerated. Diffuse iris melanoma can be managed successfully with proton beam radiation while preserving corneal limbal stem cells by harvesting them before radiation and then replacing them after irradiation. Regeneration of the palisades of Vogt could be documented by an optical coherence tomography-based imaging protocol.

DYNAMICS OF ON-DISK PLUMES AS OBSERVED WITH THE INTERFACE REGION IMAGING SPECTROGRAPH, THE ATMOSPHERIC IMAGING ASSEMBLY, AND THE HELIOSEISMIC AND MAGNETIC IMAGER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pant, Vaibhav; Mazumder, Rakesh; Banerjee, Dipankar

2015-07-01

We examine the role of small-scale transients in the formation and evolution of solar coronal plumes. We study the dynamics of plume footpoints seen in the vicinity of a coronal hole using the Atmospheric Imaging Assembly (AIA) images, the Helioseismic and Magnetic Imager magnetogram on board the Solar Dynamics Observatory and spectroscopic data from the Interface Region Imaging Spectrograph (IRIS). Quasi-periodic brightenings are observed in the base of the plumes and are associated with magnetic flux changes. With the high spectral and spatial resolution of IRIS, we identify the sources of these oscillations and try to understand what role themore » transients at the footpoints can play in sustaining the coronal plumes. IRIS “sit-and-stare” observations provide a unique opportunity to study the evolution of footpoints of the plumes. We notice enhanced line width and intensity, and large deviation from the average Doppler shift in the line profiles at specific instances, which indicate the presence of flows at the footpoints of plumes. We propose that outflows (jet-like features) as a result of small-scale reconnections affect the line profiles. These jet-like features may also be responsible for the generation of propagating disturbances (PDs) within the plumes, which are observed to be propagating to larger distances as recorded from multiple AIA channels. These PDs can be explained in terms of slow magnetoacoustic waves.« less

SIMULTANEOUS IRIS AND HINODE/EIS OBSERVATIONS AND MODELING OF THE 2014 OCTOBER 27 X2.0 CLASS FLARE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polito, V.; Reep, J. W.; Del Zanna, G.

We present a study of the X2-class flare which occurred on 2014 October 27 and was observed with the Interface Region Imaging Spectrograph (IRIS) and the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. Thanks to the high cadence and spatial resolution of the IRIS and EIS instruments, we are able to compare simultaneous observations of the Fe xxi 1354.08 Å and Fe xxiii 263.77 Å high-temperature emission (≳10 MK) in the flare ribbon during the chromospheric evaporation phase. We find that IRIS observes completely blueshifted Fe xxi line profiles, up to 200 km s{sup −1} during the rise phase of the flare, indicatingmore » that the site of the plasma upflows is resolved by IRIS. In contrast, the Fe xxiii line is often asymmetric, which we interpret as being due to the lower spatial resolution of EIS. Temperature estimates from SDO/AIA and Hinode/XRT show that hot emission (log(T[K]) > 7.2) is first concentrated at the footpoints before filling the loops. Density-sensitive lines from IRIS and EIS give estimates of electron number density of ≳10{sup 12} cm{sup −3} in the transition region lines and 10{sup 10} cm{sup −3} in the coronal lines during the impulsive phase. In order to compare the observational results against theoretical predictions, we have run a simulation of a flare loop undergoing heating using the HYDRAD 1D hydro code. We find that the simulated plasma parameters are close to the observed values that are obtained with IRIS, Hinode, and AIA. These results support an electron beam heating model rather than a purely thermal conduction model as the driving mechanism for this flare.« less

Intracellular cytoskeleton and junction proteins of endothelial cells in the porcine iris microvasculature.

PubMed

Yang, Hongfang; Yu, Paula K; Cringle, Stephen J; Sun, Xinghuai; Yu, Dao-Yi

2015-11-01

Recently we reported studies of the iris microvasculature and its endothelial cells using intra-luminal micro-perfusion, fixation, and silver staining, suggesting that the iris vascular endothelium may be crucial for maintaining homeostasis in the ocular anterior segment. Here we present information regarding the intracellular structure and cell junctions of the iris endothelium. Thirty-seven porcine eyes were used for this study. The temporal long posterior ciliary artery was cannulated to assess the iris microvascular network and its endothelium using intra-luminal micro-perfusion, fixation, and staining with phalloidin for intracellular cytoskeleton f-actin, and with antibodies against claudin-5 and VE-cadherin for junction proteins. Nuclei were counterstained with Hoechst. The iris was flat-mounted for confocal imaging. The iris microvasculature was studied for its distribution, branch orders and endothelial morphometrics with endothelial cell length measured for each vessel order. Our results showed that morphometrics of the iris microvasculature was comparable with our previous silver staining. Abundant stress fibres and peripheral border staining were seen within the endothelial cells in larger arteries. An obvious decrease in cytoplasmic stress fibres was evident further downstream in the smaller arterioles, and they tended to be absent from capillaries and veins. Endothelial intercellular junctions throughout the iris vasculature were VE-cadherin and claudin-5 immuno-positive, indicating the presence of both adherent junctions and tight junctions between vascular endothelial cells throughout the iris microvasculature. Unevenness of claudin-5 staining was noted along the endothelial cell borders in almost every order of vessels, especially in veins and small arterioles. Our results suggest that significant heterogeneity of intracellular structure and junction proteins is present in different orders of the iris vasculature in addition to vascular diameter and shape of the endothelia. Detailed information of the topography and intracellular structure and junction proteins of the endothelium of the iris microvasculature combined with unique structural features of the iris may help us to further understand the physiological and pathogenic roles of the iris vasculature in relevant ocular diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Survey of Technologies for the Airport Border of the Future

DTIC Science & Technology

2014-04-01

geometry Handwriting recognition ID cards Image classification Image enhancement Image fusion Image matching Image processing Image segmentation Iris...00 Tongue print Footstep recognition Odour recognition Retinal recognition Emotion recognition Periocular recognition Handwriting recognition Ear...recognition Palmprint recognition Hand geometry DNA matching Vein matching Ear recognition Handwriting recognition Periocular recognition Emotion

Quality-adjusted survival with combination nal-IRI+5-FU/LV vs 5-FU/LV alone in metastatic pancreatic cancer patients previously treated with gemcitabine-based therapy: a Q-TWiST analysis.

PubMed

Pelzer, Uwe; Blanc, Jean-Frédéric; Melisi, Davide; Cubillo, Antonio; Von Hoff, Daniel D; Wang-Gillam, Andrea; Chen, Li-Tzong; Siveke, Jens T; Wan, Yin; Solem, Caitlyn T; Botteman, Marc F; Yang, Yoojung; de Jong, Floris A; Hubner, Richard A

2017-05-09

In the NAPOLI-1 Phase 3 trial, nal-IRI+5-fluorouracil and leucovorin (5-FU/LV) significantly improved median overall survival (6.1 vs 4.2 months, P=0.012) and progression-free survival (3.1 vs 1.5 months, P=0.0001) vs 5-FU/LV alone in metastatic pancreatic adenocarcinoma patients previously treated with gemcitabine-based therapy. This analysis evaluated between treatment differences in quality-adjusted time without symptoms of disease progression or toxicity (Q-TWiST). Overall survival was partitioned into time with grade ⩾3 toxicity (TOX), disease progression (REL), and time without disease progression symptoms or grade ⩾3 toxicity (TWiST). Mean Q-TWiST was calculated by weighting time spent by a utility of 1.0 for TWiST and 0.5 for TOX and REL. In threshold analyses, utility for TOX and REL were varied from 0.0 to 1.0. Patients in nal-IRI+5-FU/LV (n=117) vs 5-FU/LV (n=119) had significantly more mean time in TWiST (3.4 vs 2.4 months) and TOX (1.0 vs 0.3 months) but similar REL (2.5 vs 2.7 months). In the base case, nal-IRI+5-FU/LV patients had 1.3 months (95% CI, 0.4-2.1; 5.1 vs 3.9) greater Q-TWiST (threshold analyses range: 0.9-1.6 months). Within NAPOLI-1, nal-IRI+5-FU/LV resulted in statistically significant and clinically meaningful gains in quality-adjusted survival vs 5-FU/LV alone.

KSC-2013-2909

NASA Image and Video Library

2013-06-25

VANDENBERG AIR FORCE BASE, Calif. – At Vandenberg Air Force Base in California, NASA hosted a prelaunch news conference on the Interface Region Imaging Spectrograph, or IRIS, solar observatory scheduled to launch on a Pegasus XL rocket. Participating in the news conference are George Diller, NASA Public Affairs, Geoffrey Yoder, deputy associate administrator for the Programs, Science Mission Directorate at NASA Headquarters in Washington, D.C., Tim Dunn, NASA launch director/NASA Launch Manager at the Kennedy Space Center in Florida, Bryan Baldwin, Pegasus launch vehicle program director for Orbital Sciences Corp. of Dulles, Va., Gary Kushner, IRIS project manager for Lockheed Martin's Solar and Astrophysics Laboratory in Palo Alto, Calif., and First Lt. Jennifer Kelley, launch weather officer for the U.S. Air Force 30th Operations Support Squadron at Vandenberg. Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun’s corona using spectrometry and imaging. The IRIS mission will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. For more information, visit http://www.nasa.gov/iris Photo credit: NASA/ Daniel Casper

Initial Results of a Large-scale Statistical Survey of Small-scale UV Bursts with IRIS and SDO

NASA Astrophysics Data System (ADS)

Madsen, C. A.; DeLuca, E.

2016-12-01

UV bursts are small-scale ( 1 arcsec or less) brightenings observed in the NUV/FUV passbands of the Interface Region Imaging Spectrograph (IRIS). These peculiar phenomena are found exclusively in active regions and exhibit dramatic and defining spectroscopic characteristics. In particular, they present intense broadening and splitting, often in excess of 70 km s-1, in all bright emission lines observable by IRIS. Furthermore, these broadened lines also display strong absorption from cool metallic ions such as Fe II and Ni II which typically populate the chromosphere. These features suggest that bursts are bidirectional plasma flows at transition region temperatures embedded much farther down in the cool chromosphere. To better characterize these phenomena, we have launched a statistical survey encompassing the entire IRIS data catalogue to date and its accompanying data from the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI). We sample a wide variety of IRIS observations of Si IV lines, ranging from large 400-step rasters for large detection rates to short-cadence sit-and-stare observations to provide in-depth time evolution data of individual bursts. Detection is streamlined by a semi-automated method that isolates characteristic burst spectra based on single-Gaussian fit parameters, greatly reducing search times in the vast IRIS catalogue. Our initial results demonstrate that UV bursts tend to appear when active regions are young and actively emerging, preferring to populate poorly developed inversion lines composed of numerous small mixed-polarity regions. Burst occurrence rates peak at 30-70 per hour in young active regions, decreasing as those regions age. We also find dramatic variations in spectral morphology in spatial scans of bursts with many split into distinct, opposing, resolved regions of blueshifts and redshifts. Finally, we find little evidence for coronal counterparts in AIA 171 Å, but we do find that a significant ratio of bursts coincide with localized bright features in AIA 1700 Å, lending support to the link between bursts and Ellerman bombs. With further involvement in the survey, we hope to constrain the burst/Ellerman bomb coincidence, the time evolution of burst spectral morphologies, and the distribution of their peak kinetic energies.

Quasi-periodic Oscillation of a Coronal Bright Point

NASA Astrophysics Data System (ADS)

Samanta, Tanmoy; Banerjee, Dipankar; Tian, Hui

2015-06-01

Coronal bright points (BPs) are small-scale luminous features seen in the solar corona. Quasi-periodic brightenings are frequently observed in the BPs and are generally linked with underlying magnetic flux changes. We study the dynamics of a BP seen in the coronal hole using the Atmospheric Imaging Assembly images, the Helioseismic and Magnetic Imager magnetogram on board the Solar Dynamics Observatory, and spectroscopic data from the newly launched Interface Region Imaging Spectrograph (IRIS). The detailed analysis shows that the BP evolves throughout our observing period along with changes in underlying photospheric magnetic flux and shows periodic brightenings in different EUV and far-UV images. With the highest possible spectral and spatial resolution of IRIS, we attempted to identify the sources of these oscillations. IRIS sit-and-stare observation provided a unique opportunity to study the time evolution of one footpoint of the BP as the slit position crossed it. We noticed enhanced line profile asymmetry, enhanced line width, intensity enhancements, and large deviation from the average Doppler shift in the line profiles at specific instances, which indicate the presence of sudden flows along the line-of-sight direction. We propose that transition region explosive events originating from small-scale reconnections and the reconnection outflows are affecting the line profiles. The correlation between all these parameters is consistent with the repetitive reconnection scenario and could explain the quasi-periodic nature of the brightening.

Source of Quasi-Periodic Brightenings of Solar Coronal Bright Points: Waves or Repeated Reconnections

NASA Astrophysics Data System (ADS)

Samanta, Tanmoy; Tian, Hui; Banerjee, Dipankar

2016-07-01

Coronal bright points (BPs) are small-scale luminous features seen in the solar corona. Quasi-periodic brightenings are frequently observed in the BPs and are generally linked with underlying magnetic flux changes. We study the dynamics of a BP seen in the coronal hole using the Atmospheric Imaging Assembly images, the Helioseismic and Magnetic Imager magnetogram on board the Solar Dynamics Observatory, and spectroscopic data from the newly launched Interface Region Imaging Spectrograph (IRIS). The detailed analysis shows that the BP evolves throughout our observing period along with changes in underlying photospheric magnetic flux and shows periodic brightenings in different EUV and far-UV images. With the highest possible spectral and spatial resolution of IRIS, we attempted to identify the sources of these oscillations. IRIS sit-and-stare observation provided a unique opportunity to study the time evolution of one footpoint of the BP as the slit position crossed it. We noticed enhanced line profile asymmetry, enhanced line width, intensity enhancements, and large deviation from the average Doppler shift in the line profiles at specific instances, which indicate the presence of sudden flows along the line-of-sight direction. We propose that transition region explosive events originating from small-scale reconnections and the reconnection outflows are affecting the line profiles. The correlation between all these parameters is consistent with the repetitive reconnection scenario and could explain the quasi-periodic nature of the brightening.

Spontaneous anterior chamber hemorrhage from the iris: a unique cinematographic documentation.

PubMed Central

Welch, R B

1980-01-01

A 54-year-old white female was observed with an apparent spontaneous idiopathic anterior chamber hemorrhage from the pupillary border of the iris. This event was documented by cinematography. A review of the literature concerning anterior chamber hemorrhage is presented and reports of spontaneous hyphema enumerated. The relationship of the entity of pupillary vascular tufts to the present report are discussed and etiologic factors considered. It is apparent that closer scrutiny of the pupillary border should be performed and iris angiography obtained in a variety of eyes to delineate normal and abnormal variants. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 PMID:6167051

Diannexin Protects against Renal Ischemia Reperfusion Injury and Targets Phosphatidylserines in Ischemic Tissue

PubMed Central

Wever, Kimberley E.; Wagener, Frank A. D. T. G.; Frielink, Cathelijne; Boerman, Otto C.; Scheffer, Gert J.; Allison, Anthony; Masereeuw, Rosalinde; Rongen, Gerard A.

2011-01-01

Renal ischemia/reperfusion injury (IRI) frequently complicates shock, renal transplantation and cardiac and aortic surgery, and has prognostic significance. The translocation of phosphatidylserines to cell surfaces is an important pro-inflammatory signal for cell-stress after IRI. We hypothesized that shielding of exposed phosphatidylserines by the annexin A5 (ANXA5) homodimer Diannexin protects against renal IRI. Protective effects of Diannexin on the kidney were studied in a mouse model of mild renal IRI. Diannexin treatment before renal IRI decreased proximal tubule damage and leukocyte influx, decreased transcription and expression of renal injury markers Neutrophil Gelatinase Associated Lipocalin and Kidney Injury Molecule-1 and improved renal function. A mouse model of ischemic hind limb exercise was used to assess Diannexin biodistribution and targeting. When comparing its biodistribution and elimination to ANXA5, Diannexin was found to have a distinct distribution pattern and longer blood half-life. Diannexin targeted specifically to the ischemic muscle and its affinity exceeded that of ANXA5. Targeting of both proteins was inhibited by pre-treatment with unlabeled ANXA5, suggesting that Diannexin targets specifically to ischemic tissues via phosphatidylserine-binding. This study emphasizes the importance of phosphatidylserine translocation in the pathophysiology of IRI. We show for the first time that Diannexin protects against renal IRI, making it a promising therapeutic tool to prevent IRI in a clinical setting. Our results indicate that Diannexin is a potential new imaging agent for the study of phosphatidylserine-exposing organs in vivo. PMID:21918686

Detection of trace explosives on relevant substrates using a mobile platform for photothermal infrared imaging spectroscopy (PT-IRIS)

NASA Astrophysics Data System (ADS)

Kendziora, Christopher A.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; Byers, Jeff; McGill, R. Andrew

2015-05-01

This manuscript describes the results of recent tests regarding standoff detection of trace explosives on relevant substrates using a mobile platform. We are developing a technology for detection based on photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). This approach leverages one or more microfabricated IR quantum cascade lasers, tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. Increased sensitivity to explosives and selectivity between different analyte types is achieved by narrow bandpass IR filters in the collection path. We have previously demonstrated the technique at several meters of stand-off distance indoors and in field tests, while operating the lasers below the infrared eye-safe intensity limit (100 mW/cm2). Sensitivity to explosive traces as small as a single 10 μm diameter particle (~1 ng) has been demonstrated. Analytes tested here include RDX, TNT, ammonium nitrate and sucrose. The substrates tested in this current work include metal, plastics, glass and painted car panels.

ON THE CONNECTION BETWEEN PROPAGATING SOLAR CORONAL DISTURBANCES AND CHROMOSPHERIC FOOTPOINTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryans, P.; McIntosh, S. W.; Moortel, I. De

2016-09-20

The Interface Region Imaging Spectrograph ( IRIS ) provides an unparalleled opportunity to explore the (thermal) interface between the chromosphere, transition region, and the coronal plasma observed by the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory ( SDO ). The SDO /AIA observations of coronal loop footpoints show strong recurring upward propagating signals—“propagating coronal disturbances” (PCDs) with apparent speeds of the order of 100–120 km s{sup −1}. That signal has a clear signature in the slit-jaw images of IRIS in addition to identifiable spectral signatures and diagnostics in the Mg iih (2803 Å) line. In analyzing the Mgmore » iih line, we are able to observe the presence of magnetoacoustic shock waves that are also present in the vicinity of the coronal loop footpoints. We see there is enough of a correspondence between the shock propagation in Mg iih, the evolution of the Si iv line profiles, and the PCD evolution to indicate that these waves are an important ingredient for PCDs. In addition, the strong flows in the jet-like features in the IRIS Si iv slit-jaw images are also associated with PCDs, such that waves and flows both appear to be contributing to the signals observed at the footpoints of PCDs.« less

The effects of navigator distortion and noise level on interleaved EPI DWI reconstruction: a comparison between image- and k-space-based method.

PubMed

Dai, Erpeng; Zhang, Zhe; Ma, Xiaodong; Dong, Zijing; Li, Xuesong; Xiong, Yuhui; Yuan, Chun; Guo, Hua

2018-03-23

To study the effects of 2D navigator distortion and noise level on interleaved EPI (iEPI) DWI reconstruction, using either the image- or k-space-based method. The 2D navigator acquisition was adjusted by reducing its echo spacing in the readout direction and undersampling in the phase encoding direction. A POCS-based reconstruction using image-space sampling function (IRIS) algorithm (POCSIRIS) was developed to reduce the impact of navigator distortion. POCSIRIS was then compared with the original IRIS algorithm and a SPIRiT-based k-space algorithm, under different navigator distortion and noise levels. Reducing the navigator distortion can improve the reconstruction of iEPI DWI. The proposed POCSIRIS and SPIRiT-based algorithms are more tolerable to different navigator distortion levels, compared to the original IRIS algorithm. SPIRiT may be hindered by low SNR of the navigator. Multi-shot iEPI DWI reconstruction can be improved by reducing the 2D navigator distortion. Different reconstruction methods show variable sensitivity to navigator distortion or noise levels. Furthermore, the findings can be valuable in applications such as simultaneous multi-slice accelerated iEPI DWI and multi-slab diffusion imaging. © 2018 International Society for Magnetic Resonance in Medicine.

IRIS Toxicological Review of tert-Butyl Alcohol (tert-Butanol) ...

EPA Pesticide Factsheets

In August 2013, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for TBA to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in comments on the following: Draft literature search strategies The approach for identifying studies The screening process for selecting pertinent studies The resulting list of pertinent studies Preliminary evidence tables The process for selecting studies to include in evidence tables The quality of the studies in the evidence tables The literature search strategy, which describes the processes for identifying scientific literature, contains the studies that EPA considered and selected to include in the evidence tables. The preliminary evidence tables and exposure-response arrays present the key study data in a standardized format. The evidence tables summarize the available critical scientific literature. The exposure-response figures provide a graphical representation of the responses at different levels of exposure for each study in the evidence table. EPA is undertaking a new health assessment for t-butyl alcohol (TBA) for the Integrated Risk Information System (IRIS). The outcome of this project will be a Toxicological Review and IRIS and IRIS Summary of TBA that will be entered on the IRIS database. IRIS is an EPA da

MUSTANG: A Community-Facing Web Service to Improve Seismic Data Quality Awareness Through Metrics

NASA Astrophysics Data System (ADS)

Templeton, M. E.; Ahern, T. K.; Casey, R. E.; Sharer, G.; Weertman, B.; Ashmore, S.

2014-12-01

IRIS DMC is engaged in a new effort to provide broad and deep visibility into the quality of data and metadata found in its terabyte-scale geophysical data archive. Taking advantage of large and fast disk capacity, modern advances in open database technologies, and nimble provisioning of virtual machine resources, we are creating an openly accessible treasure trove of data measurements for scientists and the general public to utilize in providing new insights into the quality of this data. We have branded this statistical gathering system MUSTANG, and have constructed it as a component of the web services suite that IRIS DMC offers. MUSTANG measures over forty data metrics addressing issues with archive status, data statistics and continuity, signal anomalies, noise analysis, metadata checks, and station state of health. These metrics could potentially be used both by network operators to diagnose station problems and by data users to sort suitable data from unreliable or unusable data. Our poster details what MUSTANG is, how users can access it, what measurements they can find, and how MUSTANG fits into the IRIS DMC's data access ecosystem. Progress in data processing, approaches to data visualization, and case studies of MUSTANG's use for quality assurance will be presented. We want to illustrate what is possible with data quality assurance, the need for data quality assurance, and how the seismic community will benefit from this freely available analytics service.

Defense Standardization Program Journal, January/March 2013

DTIC Science & Technology

2013-03-01

image plane , representing half the distance across the iris along the horizontal Pupil-to-iris ratio Degree to which the pupil is dilated or constricted... the Poincare indices, ori- entation zone coherences, entropy of local orientations, and core orien- tation field masks Number of deltas Detected deltas...based on the combination of the Poincare indices, ori- entation zone coherences, entropy of local orientations, and delta ori- entation field masks

HyspIRI Measurements of Agricultural Systems in California: 2013-2015

NASA Astrophysics Data System (ADS)

Townsend, P. A.; Kruger, E. L.; Singh, A.; Jablonski, A. D.; Kochaver, S.; Serbin, S.

2015-12-01

During 2013-2015, NASA collected high-altitude AVIRIS hyperspectral and MASTER thermal infrared imagery across large swaths of California in support of the HyspIRI planning and prototyping activities. During these campaigns, we made extensive measurements of photosynthetic capacity—Vcmax and Jmax—and their temperature sensitivities across a range of sites, crop types and environmental conditions. Our objectives were to characterize the physiological diversity of agricultural vegetation in California and develop generalizable algorithms to map these physiological parameters across several image acquisitions, regardless of crop type and canopy temperatures. We employed AVIRIS imagery to scale and estimate the vegetation parameters and MASTER surface temperature to provide context, since physiology responds exponentially to leaf temperature. We demonstrate a segmentation approach to disentangling leaf and background soil temperature, and then illustrate our retrievals of Vcmax and Jmax during overflight conditions across a large number of the 2013-2015 HyspIRI acquisitions. Our results show >80% repeatability (R2) across split sample jack-knifing, with RMSEs within 15% of the range of our data. The approach was robust across crop types (e.g., grape, almond, pistachio, avocado, pomegranate, oats, peppers, citrus, date palm, alfalfa, melons, beets) and leaf temperatures. A global imaging spectroscopy system such as HyspIRI will offer unprecedented ability to monitor agricultural crop performance under widely varying surface conditions.

Curvature of iris profile in spectral domain optical coherence tomography and dependency to refraction, age and pupil size - the MIPH Eye&Health Study.

PubMed

Schuster, Alexander K; Fischer, Joachim E; Vossmerbaeumer, Urs

2017-03-01

Optical coherence tomography (OCT) of the anterior segment allows quantitative analysis of the geometry of the iris. We performed spectral domain OCT examinations in healthy emmetropic, hyperopic and myopic subjects to investigate iris curvature and its associations. In a cross-sectional study, out of 4617 eyes (2309 subjects) those with refractive errors of <-4 or >+3 dioptres were identified by objective refraction. The iris was examined using the anterior segment mode of a spectral domain 3D OCT-2000 (Topcon Inc., Japan) in the temporal meridian, and OCT scans were investigated with respect to presence and amount of convex and concave iris configuration. Ninety-three eyes of 50 subjects served as emmetropic group (-0.5 ≤ x ≤+0.5 dioptres). Previous ocular surgery was exclusion criterion. Six hundred and sixty-eight eyes of 398 persons [292 male (76%); age range; 18-66 years] were included in the study. In the myopic group, 105 eyes had a concave iris configuration (26%), while in the hyperopic group, no eye had this configuration (0%) and in the emmetropic group five eyes (5%). Convex iris configuration was found in 96% of hyperopic, in 85% of the emmetropic and in 67% of the myopic eyes. There was an association between concave iris configuration and myopia, younger age and male gender, and with anterior chamber angle width. Spectral domain OCT images can be used for analysis of the iris structure and geometry. Our results are limited to the properties of the study population having an age range from 18 to 66 years and consisting mainly of men. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Clinical and Anterior Segment Anatomical Features in Primary Angle Closure Subgroups Based on Configurations of Iris Root Insertion.

PubMed

Hong, Ji Wook; Yun, Sung-Cheol; Sung, Kyung Rim; Lee, Jong Eun

2016-06-01

To compare the clinical and anterior segment anatomical features in primary angle closure sub-groups based on configurations of iris root insertion. Primary angle closure patients were imaged using anterior segment optical coherence tomography. Anterior chamber depth, iris curvature, iris thickness (IT) at the scleral spur and 500, 750, and 1,500 µm from the scleral spur (IT0, IT500, IT750, and IT1500), lens vault, iris area, angle opening distance (AOD500), angle recess area (ARA750), and trabecular iris space area (TISA750) were measured. Iris root insertion was categorized into a non-basal insertion group (NBG) and basal insertion group (BG). In total, 43 eyes of 39 participants belonged to the NBG and 89 eyes of 53 participants to the BG. The mean age of participants was greater in the NBG than the BG (62.7 ± 5.7 vs. 59.8 ± 7.3 years, p = 0.043), and the baseline intraocular pressure was higher in the BG than the NBG (16.4 ± 4.4 vs. 14.9 ± 3.3 mmHg, p = 0.037). The BG showed a greater IT0 (0.265 ± 0.04 vs. 0.214 ± 0.03 mm, p < 0.001) and iris area (1.59 ± 0.24 vs. 1.52 ± 0.27 mm(2), p = 0.045), lower ARA750 (0.112 ± 0.08 vs. 0.154 ± 0.08 mm(2), p = 0.017) and AOD500 (0.165 ± 0.07 vs. 0.202 ± 0.08 mm, p = 0.014) compared to the NBG. The BG had a narrower anterior chamber angle, thicker peripheral iris, and higher pretreatment intraocular pressure.

Clinical and histopathological features of adenomas of the ciliary pigment epithelium.

PubMed

Chang, Ying; Wei, Wen Bin; Shi, Ji Tong; Xian, Jun Fang; Yang, Wen Li; Xu, Xiao Lin; Bai, Hai Xia; Li, Bin; Jonas, Jost B

2016-11-01

Adenomas of the ciliary pigment epithelium (CPE) are rare benign tumours which have mainly to be differentiated from malignant ciliary body melanomas. Here we report on a consecutive series of patients with CPE adenomas and describe their characteristics. The retrospective hospital-based case series study included all patients who were consecutively operated for CPE adenomas. Of the 110 patients treated for ciliary body tumours, five patients (4.5%) had a CPE adenoma. Mean age was 59.0 ± 9.9 years (range: 46-72 years). Mean tumour apical thickness was 6.6 ± 1.7 mm. Tumour colour was mostly homogenously brown to black, and the tumour surface was smooth. The tumour masses pushed the iris tissue forward without infiltrating iris or anterior chamber angle. Sonography revealed an irregular echogram with sharp lesion borders and signs of blood flow in Color Doppler flow imaging. Ultrasonographic biomicroscopy demonstrated medium-low internal reflectivity and acoustic attenuation. In magnetic resonance imaging (MRI), the tumours as compared to brain were hyperintense on T1-weighted images and hypointense on T2-weighted images. Tumour tissue consisted of cords and nests of pigment epithelium cells separated by septa of vascularized fibrous connective tissue, leading to a pseudo-glandular appearance. The melanin granules in the cytoplasm were large and mostly spherical in shape. In four patients, the tumours were hyperpigmented. Tumour cells were large with round or oval nuclei and clearly detectable nucleoli. These clinical characteristics of CPE adenomas, such as homogenous dark brown colour, smooth surface, iris dislocation and anterior chamber angle narrowing but no iris infiltration, segmental cataract, pigment dispersion, and, as compared to brain tissue, hypointensity and, as compared to extraocular muscles or lacrimal gland, hyperintensity on T2-weighted MRI images, may be helpful for the differentiation from ciliary body malignant melanomas. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Evaluation of treatment in the Smart Home IRIS in terms of functional independence and occupational performance and satisfaction.

PubMed

Ocepek, Julija; Roberts, Anne E K; Vidmar, Gaj

2013-01-01

The development of assistive technologies, home modifications, and smart homes has rapidly advanced in the last two decades. Health professionals have recognised the benefits of these technologies in improving individual's quality of life. The Smart Home IRIS was established in 2008 within the University Rehabilitation Institute in Ljubljana with the aim to enable persons with disabilities and elderly people to test various assistive technologies and technical solutions for their independent living. We investigated the effect of treatments in the Smart Home IRIS. A convenience sample of 59 persons with disabilities and elderly people (aged 24-81 years) who were treated in the Smart Home IRIS from April to December 2011 participated. Standardised instruments--the Canadian Occupational Performance Measure (COPM) and the Functional Independence Measure (FIM)--were administered at the first assessment in the Smart Home IRIS and at a second assessment at the participant's home after 6-12 months. All the outcomes statistically significantly improved from the first to the second assessment. The treatments in the Smart Home IRIS appeared to contribute to higher occupational performance and satisfaction with performance and higher functional independence of persons with disabilities and elderly people.

Evaluation of Treatment in the Smart Home IRIS in terms of Functional Independence and Occupational Performance and Satisfaction

PubMed Central

Ocepek, Julija; Roberts, Anne E. K.; Vidmar, Gaj

2013-01-01

The development of assistive technologies, home modifications, and smart homes has rapidly advanced in the last two decades. Health professionals have recognised the benefits of these technologies in improving individual's quality of life. The Smart Home IRIS was established in 2008 within the University Rehabilitation Institute in Ljubljana with the aim to enable persons with disabilities and elderly people to test various assistive technologies and technical solutions for their independent living. We investigated the effect of treatments in the Smart Home IRIS. A convenience sample of 59 persons with disabilities and elderly people (aged 24–81 years) who were treated in the Smart Home IRIS from April to December 2011 participated. Standardised instruments—the Canadian Occupational Performance Measure (COPM) and the Functional Independence Measure (FIM)—were administered at the first assessment in the Smart Home IRIS and at a second assessment at the participant's home after 6–12 months. All the outcomes statistically significantly improved from the first to the second assessment. The treatments in the Smart Home IRIS appeared to contribute to higher occupational performance and satisfaction with performance and higher functional independence of persons with disabilities and elderly people. PMID:24348748

A pilot study using an infrared imaging system in prevention of post-endoscopic submucosal dissection ulcer bleeding.

PubMed

Yoshida, Yukinaga; Matsuda, Koji; Tamai, Naoto; Yoshizawa, Kai; Nikami, Toshiki; Ishiguro, Haruya; Tajiri, Hisao

2014-01-01

Endoscopic submucosal dissection (ESD) for superficial gastric neoplasm is a curative method. The aim of this study was to detect potential nonbleeding visible vessels (NBVVs) by using an infrared imaging (IRI) system. A total of 24 patients (25 lesions) were consecutively enrolled between March 2010 and December 2010. The day after ESD, endoscopist A (K.M.), who was blinded to the actual procedure of ESD, performed esophagogastroduodenoscopy (EGD) of the post-ESD ulcer base using the IRI system. Endoscopist A marked gray/blue points in the hard-copy images with the IRI system. After the first procedure, endoscopist B (Y.Y.), who was blinded to the results recorded by endoscopist A, performed a second EGD with white light endoscopy and administered water-jet pressure with the maximum level of an Olympus flushing pump onto the post-ESD ulcer base. This test can cause iatrogenic bleeding via application of pressure to NBVV in the post-ESD ulcer. The IRI system detected 58 gray points and 71 blue points. The post-ESD ulcer was divided into the central area and the peripheral area. There were 14 gray points (24 %) in the central area and 44 gray points (76 %) in the peripheral area. There were 19 blue points (27 %) in the central area and 52 blue points (73 %) in the peripheral area. There was no significant difference when comparing the distribution of gray points and blue points. Bleeding occurred with a water-jet pressure in 11 of 58 gray points and in none of the blue points (P = 0.000478). Among the gray points, bleeding in response to a water-jet pressure occurred in 2 points in the central area and in 9 points in the peripheral area. The IRI system detects visible vessels (VVs) that are in no need of coagulation as blue points, and VVs have a potential risk of bleeding as gray points.

Biometric Factors Associated With Acute Primary Angle Closure: Comparison of the Affected and Fellow Eye.

PubMed

Atalay, Eray; Nongpiur, Monisha E; Baskaran, Mani; Sharma, Sourabh; Perera, Shamira A; Aung, Tin

2016-10-01

To compare ocular biometric and anterior segment parameters between the affected and fellow eye in subjects with acute primary angle closure (APAC). We evaluated 76 subjects with unilateral APAC who had undergone bilateral laser peripheral iridotomy before enrollment. Imaging was done using anterior segment optical coherence tomography and a customized software was used to measure the following: angle opening distance (AOD750); trabecular-iris space area (TISA750); iris thickness (IT750); iris curvature (ICURV); iris area (IAREA); anterior chamber depth; area and volume (ACD; ACA and ACV); anterior chamber width (ACW); anterior vault (ACD+LV); lens vault (LV); and pupil diameter (PD). We used A-scan ultrasonography to measure axial length (AL) and lens thickness (LT). Mean differences in ocular biometric and anterior segment parameters were assessed using linear mixed model adjusting for PD. A total of 53 subjects (36 females, 67.9%) with a mean age of 62.7 ± 8.1 years were analyzed after excluding 17 unanalyzable images in at least one eye. Affected eyes had shallower ACD, smaller ACA, ACV, anterior vault, TISA750, AOD750, and ICURV (all P < 0.05). Axial length, ACW, LV, LT, IAREA, and IT750 did not differ between the eyes. In the affected eyes, IT750 was significantly associated AOD750 (P < 0.05); whereas in the fellow eyes, IT750 and AL was predictive of AOD750 (all P < 0.05). Eyes with previous APAC had smaller anterior segment dimensions when compared with their fellow eyes. Iris thickness was the strongest predictor of angle width in both affected and fellow eyes.

Supporting flight data analysis for Space Shuttle Orbiter Experiments at NASA Ames Research Center

NASA Technical Reports Server (NTRS)

Green, M. J.; Budnick, M. P.; Yang, L.; Chiasson, M. P.

1983-01-01

The Space Shuttle Orbiter Experiments program in responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The Infrared Imagery of Shuttle (IRIS), Catalytic Surface Effects, and Tile Gap Heating experiments sponsored by Ames Research Center are part of this program. The paper describes the software required to process the flight data which support these experiments. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques have provided information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third Shuttle mission.

Supporting flight data analysis for Space Shuttle Orbiter experiments at NASA Ames Research Center

NASA Technical Reports Server (NTRS)

Green, M. J.; Budnick, M. P.; Yang, L.; Chiasson, M. P.

1983-01-01

The space shuttle orbiter experiments program is responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The infrared imagery of shuttle (IRIS), catalytic surface effects, and tile gap heating experiments sponsored by Ames Research Center are part of this program. The software required to process the flight data which support these experiments is described. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques provide information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third shuttle mission.

The role of the lens in pigment dispersion syndrome.

PubMed

Liu, Lance

2010-12-01

In patients with pigment dispersion syndrome, changes of the iris configuration can occur with accommodation, blinking, miotics, and following a laser iridotomy. This observational case series looks at the changes following cataract surgery in 3 eyes with signs of pigment dispersion, symptomatic cataracts, and no previous laser iridotomy that were imaged with optical coherence tomography. The iris was concave posteriorly in dark and light lighting conditions, and became flat following an uncomplicated cataract operation. This may be explained by the elimination of iridolenticular contact, which contributes to the mechanism of reverse pupil block. These iris changes suggest the lens plays an important role in the mechanism of pigment dispersion. Copyright 2010, SLACK Incorporated.

Conversion from mutual helicity to self-helicity observed with IRIS

NASA Astrophysics Data System (ADS)

Li, L. P.; Peter, H.; Chen, F.; Zhang, J.

2014-10-01

Context. In the upper atmosphere of the Sun observations show convincing evidence for crossing and twisted structures, which are interpreted as mutual helicity and self-helicity. Aims: We use observations with the new Interface Region Imaging Spectrograph (IRIS) to show the conversion of mutual helicity into self-helicity in coronal structures on the Sun. Methods: Using far UV spectra and slit-jaw images from IRIS and coronal images and magnetograms from SDO, we investigated the evolution of two crossing loops in an active region, in particular, the properties of the Si IV line profile in cool loops. Results: In the early stage two cool loops cross each other and accordingly have mutual helicity. The Doppler shifts in the loops indicate that they wind around each other. As a consequence, near the crossing point of the loops (interchange) reconnection sets in, which heats the plasma. This is consistent with the observed increase of the line width and of the appearance of the loops at higher temperatures. After this interaction, the two new loops run in parallel, and in one of them shows a clear spectral tilt of the Si IV line profile. This is indicative of a helical (twisting) motion, which is the same as to say that the loop has self-helicity. Conclusions: The high spatial and spectral resolution of IRIS allowed us to see the conversion of mutual helicity to self-helicity in the (interchange) reconnection of two loops. This is observational evidence for earlier theoretical speculations. Movie associated with Fig. 1 and Appendix A are available in electronic form at http://www.aanda.org

Efficient quantitative assessment of facial paralysis using iris segmentation and active contour-based key points detection with hybrid classifier.

PubMed

Barbosa, Jocelyn; Lee, Kyubum; Lee, Sunwon; Lodhi, Bilal; Cho, Jae-Gu; Seo, Woo-Keun; Kang, Jaewoo

2016-03-12

Facial palsy or paralysis (FP) is a symptom that loses voluntary muscles movement in one side of the human face, which could be very devastating in the part of the patients. Traditional methods are solely dependent to clinician's judgment and therefore time consuming and subjective in nature. Hence, a quantitative assessment system becomes apparently invaluable for physicians to begin the rehabilitation process; and to produce a reliable and robust method is challenging and still underway. We introduce a novel approach for a quantitative assessment of facial paralysis that tackles classification problem for FP type and degree of severity. Specifically, a novel method of quantitative assessment is presented: an algorithm that extracts the human iris and detects facial landmarks; and a hybrid approach combining the rule-based and machine learning algorithm to analyze and prognosticate facial paralysis using the captured images. A method combining the optimized Daugman's algorithm and Localized Active Contour (LAC) model is proposed to efficiently extract the iris and facial landmark or key points. To improve the performance of LAC, appropriate parameters of initial evolving curve for facial features' segmentation are automatically selected. The symmetry score is measured by the ratio between features extracted from the two sides of the face. Hybrid classifiers (i.e. rule-based with regularized logistic regression) were employed for discriminating healthy and unhealthy subjects, FP type classification, and for facial paralysis grading based on House-Brackmann (H-B) scale. Quantitative analysis was performed to evaluate the performance of the proposed approach. Experiments show that the proposed method demonstrates its efficiency. Facial movement feature extraction on facial images based on iris segmentation and LAC-based key point detection along with a hybrid classifier provides a more efficient way of addressing classification problem on facial palsy type and degree of severity. Combining iris segmentation and key point-based method has several merits that are essential for our real application. Aside from the facial key points, iris segmentation provides significant contribution as it describes the changes of the iris exposure while performing some facial expressions. It reveals the significant difference between the healthy side and the severe palsy side when raising eyebrows with both eyes directed upward, and can model the typical changes in the iris region.

Efficient iris texture analysis method based on Gabor ordinal measures

NASA Astrophysics Data System (ADS)

Tajouri, Imen; Aydi, Walid; Ghorbel, Ahmed; Masmoudi, Nouri

2017-07-01

With the remarkably increasing interest directed to the security dimension, the iris recognition process is considered to stand as one of the most versatile technique critically useful for the biometric identification and authentication process. This is mainly due to every individual's unique iris texture. A modestly conceived efficient approach relevant to the feature extraction process is proposed. In the first place, iris zigzag "collarette" is extracted from the rest of the image by means of the circular Hough transform, as it includes the most significant regions lying in the iris texture. In the second place, the linear Hough transform is used for the eyelids' detection purpose while the median filter is applied for the eyelashes' removal. Then, a special technique combining the richness of Gabor features and the compactness of ordinal measures is implemented for the feature extraction process, so that a discriminative feature representation for every individual can be achieved. Subsequently, the modified Hamming distance is used for the matching process. Indeed, the advanced procedure turns out to be reliable, as compared to some of the state-of-the-art approaches, with a recognition rate of 99.98%, 98.12%, and 95.02% on CASIAV1.0, CASIAV3.0, and IIT Delhi V1 iris databases, respectively.

Use of IRIS image-enhancement facilities on digital images by radiologists during a clinical trial at the Ottawa Civic Hospital

NASA Astrophysics Data System (ADS)

Coristine, Marjorie; Goldberg, Morris; Beeton, Carolyn; Dillon, Richard F.; Tombaugh, Jo W.; Belanger, Garry; Ahuja, J.

1990-07-01

The Integrated Radiological Information System (IRIS) supports the capture and distribution of digitized x-ray images and voice reports in the form of " electronic" patient folders which can be accessed at physician workstations throughout the hospital. Each workstation has an image screen to display documents and x-ray images a control screen to access patient folders and a hands-free telephone to dictate and play back reports and enable consultation between radiologist and clinician workstations. A seven week clinical trial of IRIS was conducted at the Ottawa Civic Hospital during April and May 1989. The system operated to process cases from the Department of Emergency Medicine weekday afternoons. Observers recorded for each case how radiologists used the system. After the trial radiologists participated in an extensive debriefing interview during which they were asked to complete a number of rating scales addressing the following issues: 1) willingness to diagnose by tissue type and by type of pathology 2) seriousness of problems due to system limitations 3) the perceived usefulness of enhancement capabilities and measurement tools. Overall the system was found to be acceptable by the radiologists. There was some concern about diagnosis in soft tissue regions. Most of the system features were regarded as acceptable but there were areas which needed improvement. The suggested improvements are described where applicable. The enhancement facilities and the means of using the facilities were acceptable overall. 426 /

Graphics and Flow Visualization of Computer Generated Flow Fields

NASA Technical Reports Server (NTRS)

Kathong, M.; Tiwari, S. N.

1987-01-01

Flow field variables are visualized using color representations described on surfaces that are interpolated from computational grids and transformed to digital images. Techniques for displaying two and three dimensional flow field solutions are addressed. The transformations and the use of an interactive graphics program for CFD flow field solutions, called PLOT3D, which runs on the color graphics IRIS workstation are described. An overview of the IRIS workstation is also described.

Immune Reconstitution Inflammatory Syndrome Unmasking or Worsening AIDS-Related Progressive Multifocal Leukoencephalopathy: A Literature Review.

PubMed

Fournier, Anna; Martin-Blondel, Guillaume; Lechapt-Zalcman, Emmanuèle; Dina, Julia; Kazemi, Apolline; Verdon, Renaud; Mortier, Emmanuel; de La Blanchardière, Arnaud

2017-01-01

Incidence of progressive multifocal leukoencephalopathy (PML) in HIV-infected patients has declined in the combined antiretroviral therapy (cART) era although a growing number of acquired immunodeficiency syndrome (AIDS)-related PML-immune reconstitution inflammatory syndromes (PML-IRIS) have been published during the same period. Therapeutic management of PML-IRIS is not consensual and mainly relies on corticosteroids. Our main aim was, in addition to provide a thoughtful analysis of published PML-IRIS cases, to assess the benefit of corticosteroids in the management of PML-IRIS, focusing on confirmed cases. We performed a literature review of the 46 confirmed cases of PML-IRIS cases occurring in HIV-infected patients from 1998 to September 2016 (21 unmasking and 25 paradoxical PML-IRIS). AIDS-related PML-IRIS patients were mostly men (sex ratio 4/1) with a median age of 40.5 years (range 12-66). Median CD4 T cell count before cART and at PML-IRIS onset was 45/μl (0-301) and 101/μl (20-610), respectively. After cART initiation, PML-IRIS occurred within a median timescale of 38 days (18-120). Clinical signs were motor deficits (69%), speech disorders (36%), cognitive disorders (33%), cerebellar ataxia (28%), and visual disturbances (23%). Brain MRI revealed hyperintense areas on T2-weighted sequences and FLAIR images (76%) and suggestive contrast enhancement (87%). PCR for John Cunningham virus (JCV) in cerebrospinal fluid (CSF) was positive in only 84% of cases; however, when performed, brain biopsy confirmed diagnosis of PML in 90% of cases and demonstrated histological signs of IRIS in 95% of cases. Clinical worsening related to PML-IRIS and leading to death was observed in 28% of cases. Corticosteroids were prescribed in 63% of cases and maraviroc in one case. Statistical analysis failed to demonstrate significant benefit from steroid treatment, despite spectacular improvement in certain cases. Diagnosis of PML-IRIS should be considered in HIV-infected patients with worsening neurological symptoms after initiation or resumption of effective cART, independently of CD4 cell count prior to cART. If PCR for JCV is negative in CSF, brain biopsy should be discussed. Only large multicentric randomized trials could potentially demonstrate the possible efficacy of corticosteroids and/or CCR5 antagonists in the management of PML-IRIS.

Immune Reconstitution Inflammatory Syndrome Unmasking or Worsening AIDS-Related Progressive Multifocal Leukoencephalopathy: A Literature Review

PubMed Central

Fournier, Anna; Martin-Blondel, Guillaume; Lechapt-Zalcman, Emmanuèle; Dina, Julia; Kazemi, Apolline; Verdon, Renaud; Mortier, Emmanuel; de La Blanchardière, Arnaud

2017-01-01

Incidence of progressive multifocal leukoencephalopathy (PML) in HIV-infected patients has declined in the combined antiretroviral therapy (cART) era although a growing number of acquired immunodeficiency syndrome (AIDS)-related PML-immune reconstitution inflammatory syndromes (PML-IRIS) have been published during the same period. Therapeutic management of PML-IRIS is not consensual and mainly relies on corticosteroids. Our main aim was, in addition to provide a thoughtful analysis of published PML-IRIS cases, to assess the benefit of corticosteroids in the management of PML-IRIS, focusing on confirmed cases. We performed a literature review of the 46 confirmed cases of PML-IRIS cases occurring in HIV-infected patients from 1998 to September 2016 (21 unmasking and 25 paradoxical PML-IRIS). AIDS-related PML-IRIS patients were mostly men (sex ratio 4/1) with a median age of 40.5 years (range 12–66). Median CD4 T cell count before cART and at PML-IRIS onset was 45/μl (0–301) and 101/μl (20–610), respectively. After cART initiation, PML-IRIS occurred within a median timescale of 38 days (18–120). Clinical signs were motor deficits (69%), speech disorders (36%), cognitive disorders (33%), cerebellar ataxia (28%), and visual disturbances (23%). Brain MRI revealed hyperintense areas on T2-weighted sequences and FLAIR images (76%) and suggestive contrast enhancement (87%). PCR for John Cunningham virus (JCV) in cerebrospinal fluid (CSF) was positive in only 84% of cases; however, when performed, brain biopsy confirmed diagnosis of PML in 90% of cases and demonstrated histological signs of IRIS in 95% of cases. Clinical worsening related to PML-IRIS and leading to death was observed in 28% of cases. Corticosteroids were prescribed in 63% of cases and maraviroc in one case. Statistical analysis failed to demonstrate significant benefit from steroid treatment, despite spectacular improvement in certain cases. Diagnosis of PML-IRIS should be considered in HIV-infected patients with worsening neurological symptoms after initiation or resumption of effective cART, independently of CD4 cell count prior to cART. If PCR for JCV is negative in CSF, brain biopsy should be discussed. Only large multicentric randomized trials could potentially demonstrate the possible efficacy of corticosteroids and/or CCR5 antagonists in the management of PML-IRIS. PMID:28588577

Convolution Comparison Pattern: An Efficient Local Image Descriptor for Fingerprint Liveness Detection

PubMed Central

Gottschlich, Carsten

2016-01-01

We present a new type of local image descriptor which yields binary patterns from small image patches. For the application to fingerprint liveness detection, we achieve rotation invariant image patches by taking the fingerprint segmentation and orientation field into account. We compute the discrete cosine transform (DCT) for these rotation invariant patches and attain binary patterns by comparing pairs of two DCT coefficients. These patterns are summarized into one or more histograms per image. Each histogram comprises the relative frequencies of pattern occurrences. Multiple histograms are concatenated and the resulting feature vector is used for image classification. We name this novel type of descriptor convolution comparison pattern (CCP). Experimental results show the usefulness of the proposed CCP descriptor for fingerprint liveness detection. CCP outperforms other local image descriptors such as LBP, LPQ and WLD on the LivDet 2013 benchmark. The CCP descriptor is a general type of local image descriptor which we expect to prove useful in areas beyond fingerprint liveness detection such as biological and medical image processing, texture recognition, face recognition and iris recognition, liveness detection for face and iris images, and machine vision for surface inspection and material classification. PMID:26844544

The infrared imaging spectrograph (IRIS) for TMT: reflective ruled diffraction grating performance testing and discussion

NASA Astrophysics Data System (ADS)

Meyer, Elliot; Chen, Shaojie; Wright, Shelley A.; Moore, Anna M.; Larkin, James E.; Simard, Luc; Marie, Jerome; Mieda, Etsuko; Gordon, Jacob

2014-07-01

We present the efficiency of near-infrared reflective ruled diffraction gratings designed for the InfraRed Imaging Spectrograph (IRIS). IRIS is a first light, integral field spectrograph and imager for the Thirty Meter Telescope (TMT) and narrow field infrared adaptive optics system (NFIRAOS). IRIS will operate across the near-infrared encompassing the ZYJHK bands (~0.84 - 2.4μm) with multiple spectral resolutions. We present our experimental setup and analysis of the efficiency of selected reflective diffraction gratings. These measurements are used as a comparison sample against selected candidate Volume Phase Holographic (VPH) gratings (see Chen et al., this conference). We investigate the efficiencies of five ruled gratings designed for IRIS from two separate vendors. Three of the gratings accept a bandpass of 1.19-1.37μm (J band) with ideal spectral resolutions of R=4000 and R=8000, groove densities of 249 and 516 lines/mm, and blaze angles of 9.86° and 20.54° respectively. The other two gratings accept a bandpass of 1.51-1.82μm (H Band) with an ideal spectral resolution of R=4000, groove density of 141 lines/mm, and blaze angle of 9.86°. The fraction of flux in each diffraction mode was compared to both a pure reflection mirror as well as the sum of the flux measured in all observable modes. We measure the efficiencies off blaze angle for all gratings and the efficiencies between the polarization transverse magnetic (TM) and transverse electric (TE) states. The peak reflective efficiencies are 98.90 +/- 3.36% (TM) and 84.99 +/- 2.74% (TM) for the H-band R=4000 and J-band R=4000 respectively. The peak reflective efficiency for the J-band R=8000 grating is 78.78 +/- 2.54% (TE). We find that these ruled gratings do not exhibit a wide dependency on incident angle within +/-3°. Our best-manufactured gratings were found to exhibit a dependency on the polarization state of the incident beam with a ~10-20% deviation, consistent with the theoretical efficiency predictions. This work will significantly contribute to the selection of the final grating type and vendor for the IRIS optical system, and are also pertinent to current and future near-infrared astronomical spectrographs.

An alternative method for irones quantification in iris rhizomes using headspace solid-phase microextraction.

PubMed

Roger, B; Fernandez, X; Jeannot, V; Chahboun, J

2010-01-01

The essential oil obtained from iris rhizomes is one of the most precious raw materials for the perfume industry. Its fragrance is due to irones that are gradually formed by oxidative degradation of iridals during rhizome ageing. The development of an alternative method allowing irone quantification in iris rhizomes using HS-SPME-GC. The development of the method using HS-SPME-GC was achieved using the results obtained from a conventional method, i.e. a solid-liquid extraction (SLE) followed by irone quantification by CG. Among several calibration methods tested, internal calibration gave the best results and was the least sensitive to the matrix effect. The proposed method using HS-SPME-GC is as accurate and reproducible as the conventional one using SLE. These two methods were used to monitor and compare irone concentrations in iris rhizomes that had been stored for 6 months to 9 years. Irone quantification in iris rhizome can be achieved using HS-SPME-GC. This method can thus be used for the quality control of the iris rhizomes. It offers the advantage of combining extraction and analysis with an automated device and thus allows a large number of rhizome batches to be analysed and compared in a limited amount of time. Copyright © 2010 John Wiley & Sons, Ltd.

EO-1/Hyperion: Nearing Twelve Years of Successful Mission Science Operation and Future Plans

NASA Technical Reports Server (NTRS)

Middleton, Elizabeth M.; Campbell, Petya K.; Huemmrich, K. Fred; Zhang, Qingyuan; Landis, David R.; Ungar, Stephen G.; Ong, Lawrence; Pollack, Nathan H.; Cheng, Yen-Ben

2012-01-01

The Earth Observing One (EO-1) satellite is a technology demonstration mission that was launched in November 2000, and by July 2012 will have successfully completed almost 12 years of high spatial resolution (30 m) imaging operations from a low Earth orbit. EO-1 has two unique instruments, the Hyperion and the Advanced Land Imager (ALI). Both instruments have served as prototypes for NASA's newer satellite missions, including the forthcoming (in early 2013) Landsat-8 and the future Hyperspectral Infrared Imager (HyspIRI). As well, EO-1 is a heritage platform for the upcoming German satellite, EnMAP (2015). Here, we provide an overview of the mission, and highlight the capabilities of the Hyperion for support of science investigations, and present prototype products developed with Hyperion imagery for the HyspIRI and other space-borne spectrometers.

An IRIS Optically Thin View of the Dynamics of the Solar Chromosphere

NASA Astrophysics Data System (ADS)

Carlsson, M.

2017-12-01

We analyze the formation of the O I 1356 and Cl I 1351 lines and show that they are formed in the mid-chromosphere and are optically thin. Their non-thermal line-widths are thus a direct measure of the velocity field along the line of sight. We use this insight to analyze a large set of observations from the Interface Region Imaging Spectrograph (IRIS) to study the dynamics of the Solar Chromosphere.

Evidence from IRIS that Sunspot Large Penumbral Jets Spin

NASA Technical Reports Server (NTRS)

Tiwari, Sanjiv K.; Moore, Ronald L.; De Pontieu, Bart; Tarbell, Theodore D.; Panesar, Navdeep K.; Winebarger, Amy R.; Sterling, Alphonse C.

2017-01-01

Recent observations from Hinode (SOT/FG) revealed the presence of large penumbral jets (widths = 500 km, larger than normal penumbral microjets, which have widths < 400 km) repeatedly occurring at the same locations in a sunspot penumbra, at the tail of a filament or where the tails of several penumbral filaments apparently converge (Tiwari et al. 2016, ApJ). These locations were observed to have mixed-polarity flux in Stokes-V images from SOT/FG. Large penumbral jets displayed direct signatures in AIA 1600, 304, 171, and 193 channels; thus they were heated to at least transition region temperatures. Because large jets could not be detected in AIA 94 Å, whether they had any coronal-temperature plasma remains unclear. In the present work, for another sunspot, we use IRIS Mg II k 2796 Å slit jaw images and spectra and magnetograms from Hinode SOT/FG and SOT/SP to examine: whether penumbral jets spin, similar to spicules and coronal jets in the quiet Sun and coronal holes; whether they stem from mixed-polarity flux; and whether they produce discernible coronal emission, especially in AIA 94 Å images. The few large penumbral jets for which we have IRIS spectra show evidence of spin. If these have mixed-polarity at their base, then they might be driven the same way as coronal jets and CMEs.

Interferometric biosensing platform for multiplexed digital detection of viral pathogens and biomarkers

NASA Astrophysics Data System (ADS)

Daaboul, George

Label-free optical biosensors have been established as proven tools for monitoring specific biomolecular interactions. However, compact and robust embodiments of such instruments have yet to be introduced in order to provide sensitive, quantitative, and high-throughput biosensing for low-cost research and clinical applications. Here we present the interferometric reflectance-imaging sensor (IRIS). IRIS allows sensitive label free analysis using an inexpensive and durable multi-color LED illumination source on a silicon based surface. IRIS monitors biomolecular interaction through measurement of biomass addition to the sensor's surface. We demonstrate the capability of this system to dynamically monitor antigen---antibody interactions with a noise floor of 5.2 pg/mm 2 and DNA single mismatch detection under isothermal melting conditions in an array format. Ensemble detection of binding events using IRIS did not provide the sensitivity needed for detection of infectious disease and biomarkers at clinically relevant concentrations. Therefore, a new approach was adapted to the IRIS platform that allowed the detection and identification of individual nanoparticles on the sensor's surface. The new detection method was termed single-particle IRIS (SP-IRIS). We developed two detection modalities for SP-IRIS. The first modality is when the target is a nanoparticle such as a virus. We verified that SP-IRIS can accurately detect and size individual viral particles. Then we demonstrated that single nanoparticle counting and sizing methodology on SP-IRIS leads to a specific and sensitive virus sensor that can be multiplexed. Finally, we developed an assay for the detection of Ebola and Marburg. A detection limit of 3 x 103 PFU/ml was demonstrated for vesicular stomatitis virus (VSV) pseudotyped with Ebola or Marburg virus glycoprotein. We have demonstrated that virus detection can be done in human whole blood directly without the need for sample preparation. The second modality of SP-IRIS we developed was single molecule counting of biomarkers utilizing a sandwich assay with detection probes labeled with gold nanoparticles. We demonstrated the use of single molecule counting in a nucleic acid assay for melanoma biomarker detection. We showed that a single molecule counting assay can lead to detection limits in the attomolar range. The improved sensitivity of IRIS utilizing single nanoparticle detection holds promise for a simple and low-cost technology for rapid virus detection and multiplexed molecular screening for clinical applications.

KSC-2013-2939

NASA Image and Video Library

2013-06-27

VANDENBERG AIR FORCE BASE, Calif. – The Orbital Sciences L-1011 aircraft takes off from Vandenberg Air Force Base in California at 9:30 p.m. EDT, headed over the Pacific Ocean to release the Pegasus XL rocket carrying NASA's Interface Region Imaging Spectrograph, or IRIS, solar observatory. Release of the rocket from under the wing of the aircraft is scheduled for 10:27 p.m. EDT. IRIS will open a new window of discovery using spectrometry and imaging to trace the flow of energy and plasma through the chromospheres and transition region into the sun’s corona. The spacecraft will observe how solar material moves, gathers energy and heats up as it travels through a largely unexplored region of the solar atmosphere. This interface region, located between the sun's visible surface and its upper atmosphere, is where most of its ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate. NASA's Launch Services Program at the agency's Kennedy Space Center in Florida is managing the countdown and launch. For more information, visit http://www.nasa.gov/iris. Photo credit: NASA/Daniel Casper

Are IRIS Bombs Connected to Ellerman Bombs?

NASA Astrophysics Data System (ADS)

Tian, Hui; Xu, Zhi; He, Jiansen; Madsen, Chad

2016-06-01

Recent observations by the Interface Region Imaging Spectrograph (IRIS) have revealed pockets of hot gas (˜2-8 × 104 K) potentially resulting from magnetic reconnection in the partially ionized lower solar atmosphere (IRIS bombs; IBs). Using joint observations between IRIS and the Chinese New Vacuum Solar Telescope, we have identified 10 IBs. We find that 3 are unambiguously and 3 others are possibly connected to Ellerman bombs (EBs), which show intense brightening of the extended {{{H}}}α wings without leaving an obvious signature in the {{{H}}}α core. These bombs generally reveal the following distinct properties: (1) the O IV 1401.156 Å and 1399.774 Å lines are absent or very weak; (2) the Mn I 2795.640 Å line manifests as an absorption feature superimposed on the greatly enhanced Mg II k line wing; (3) the Mg II k and h lines show intense brightening in the wings and no dramatic enhancement in the cores; (4) chromospheric absorption lines such as Ni II 1393.330 Å and 1335.203 Å are very strong; and (5) the 1700 Å images obtained with the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory reveal intense and compact brightenings. These properties support the formation of these bombs in the photosphere, demonstrating that EBs can be heated much more efficiently than previously thought. We also demonstrate that the Mg II k and h lines can be used to investigate EBs similarly to {{{H}}}α , which opens a promising new window for EB studies. The remaining four IBs obviously have no connection to EBs and they do not have the properties mentioned above, suggesting a higher formation layer, possibly in the chromosphere.

Digital cartography of Io

NASA Technical Reports Server (NTRS)

Mcewen, Alfred S.; Duck, B.; Edwards, Kathleen

1991-01-01

A high resolution controlled mosaic of the hemisphere of Io centered on longitude 310 degrees is produced. Digital cartographic techniques were employed. Approximately 80 Voyager 1 clear and blue filter frames were utilized. This mosaic was merged with low-resolution color images. This dataset is compared to the geologic map of this region. Passage of the Voyager spacecraft through the Io plasma torus during acquisition of the highest resolution images exposed the vidicon detectors to ionized radiation, resulting in dark-current buildup on the vidicon. Because the vidicon is scanned from top to bottom, more charge accumulated toward the bottom of the frames, and the additive error increases from top to bottom as a ramp function. This ramp function was removed by using a model. Photometric normalizations were applied using the Minnaert function. An attempt to use Hapke's photometric function revealed that this function does not adequately describe Io's limb darkening at emission angles greater than 80 degrees. In contrast, the Minnaert function accurately describes the limb darkening up to emission angles of about 89 degrees. The improved set of discrete camera angles derived from this effort will be used in conjunction with the space telemetry pointing history file (the IPPS file), corrected on 4 or 12 second intervals to derive a revised time history for the pointing of the Infrared Interferometric Spectrometer (IRIS). For IRIS observations acquired between camera shutterings, the IPPS file can be corrected by linear interpolation, provided that the spacecraft motions were continuous. Image areas corresponding to the fields of view of IRIS spectra acquired between camera shutterings will be extracted from the mosaic to place the IRIS observations and hotspot models into geologic context.

NASA 2008 HyspIRI whitepaper and workshop report

USGS Publications Warehouse

,; Mars, John

2009-01-01

From October 21-23, 2008, NASA held a three-day workshop to consider the Hyperspectral Infrared Imager (HyspIRI) mission recommended for implementation by the 2007 report from the U.S. National Research Council Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, also known as the Earth Science Decadal Survey. The open workshop provided a forum to present the initial observational requirements for the mission and assess its anticipated impact on scientific and operational applications as well as obtain feedback from the broader scientific community on the mission concept. The workshop participants concluded the HyspIRI mission would provide a significant new capability to study ecosystems and natural hazards at spatial scales relevant to human resource use. In addition, participants confirmed that the proposed instrument designs could meet the measurement requirements and be implemented through the use of current technology. The workshop participants, like the Decadal Survey itself, strongly endorsed the need for the HyspIRI mission and felt the mission, as defined, would accomplish the intended science.

Face-iris multimodal biometric scheme based on feature level fusion

NASA Astrophysics Data System (ADS)

Huo, Guang; Liu, Yuanning; Zhu, Xiaodong; Dong, Hongxing; He, Fei

2015-11-01

Unlike score level fusion, feature level fusion demands all the features extracted from unimodal traits with high distinguishability, as well as homogeneity and compatibility, which is difficult to achieve. Therefore, most multimodal biometric research focuses on score level fusion, whereas few investigate feature level fusion. We propose a face-iris recognition method based on feature level fusion. We build a special two-dimensional-Gabor filter bank to extract local texture features from face and iris images, and then transform them by histogram statistics into an energy-orientation variance histogram feature with lower dimensions and higher distinguishability. Finally, through a fusion-recognition strategy based on principal components analysis and support vector machine (FRSPS), feature level fusion and one-to-n identification are accomplished. The experimental results demonstrate that this method can not only effectively extract face and iris features but also provide higher recognition accuracy. Compared with some state-of-the-art fusion methods, the proposed method has a significant performance advantage.

Coastal and Inland Aquatic Data Products for the Hyperspectral Infrared Imager (HyspIRI)

NASA Technical Reports Server (NTRS)

Abelev, Andrei; Babin, Marcel; Bachmann, Charles; Bell, Thomas; Brando, Vittorio; Byrd, Kristin; Dekker , Arnold; Devred, Emmanuel; Forget, Marie-Helene; Goodman, James;

Prominence plasma and magnetic field structure - A coordinated observation with IRIS, Hinode and THEMIS

NASA Astrophysics Data System (ADS)

Schmieder, Brigitte; Labrosse, Nicolas; Levens, Peter; Lopez Ariste, Arturo

2016-07-01

During an international campaign in 2014, utilising both space-based (IRIS and Hinode) and ground-based (THEMIS) instruments, we focused on observing prominences. We compare IRIS observations with those of Hinode (EIS and SOT) in order to build a more complete picture of the prominence structure for a quiescent prominence observed on 15 July 2014, identified to have tornado-like structure. THEMIS provides valuable information on the orientation and strength of the internal magnetic field. Here we find there is almost ubiquitously horizontal field with respect to the local limb, with possibly a turbulent component. The Mg II lines form the majority of our IRIS analysis, with a mixture of reversed and non-reversed profiles present in the prominence spectra. Comparing the differences between the Mg II data from IRIS and the Ca II images from Hinode/SOT provides an intriguing insight into the prominence legs in these channels. We present plasma diagnostics from IRIS, with line of sight velocities of around 10 km/s in either direction along the magnetic loops of material in the front of the prominence, and line widths comparable to those found for prominences by previous authors (e.g. Schmieder et al. 2014). We also take a look into the lines formed at higher, coronal plasma temperatures, as seen by Hinode/EIS, to compare plasma structures at a full range of temperatures.

Fourier transform infrared spectroscopy to quantify collagen and elastin in an in vitro model of extracellular matrix degradation in aorta.

PubMed

Cheheltani, Rabee; McGoverin, Cushla M; Rao, Jayashree; Vorp, David A; Kiani, Mohammad F; Pleshko, Nancy

2014-06-21

Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues.

Fourier Transform Infrared Spectroscopy to Quantify Collagen and Elastin in an In Vitro Model of Extracellular Matrix Degradation in Aorta

PubMed Central

Cheheltani, Rabee; McGoverin, Cushla M.; Rao, Jayashree; Vorp, David A.; Kiani, Mohammad F.; Pleshko, N.

2014-01-01

Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues. PMID:24761431

Iris features-based heart disease diagnosis by computer vision

NASA Astrophysics Data System (ADS)

Nguchu, Benedictor A.; Li, Li

2017-07-01

The study takes advantage of several new breakthroughs in computer vision technology to develop a new mid-irisbiomedical platform that processes iris image for early detection of heart-disease. Guaranteeing early detection of heart disease provides a possibility of having non-surgical treatment as suggested by biomedical researchers and associated institutions. However, our observation discovered that, a clinical practicable solution which could be both sensible and specific for early detection is still lacking. Due to this, the rate of majority vulnerable to death is highly increasing. The delayed diagnostic procedures, inefficiency, and complications of available methods are the other reasons for this catastrophe. Therefore, this research proposes the novel IFB (Iris Features Based) method for diagnosis of premature, and early stage heart disease. The method incorporates computer vision and iridology to obtain a robust, non-contact, nonradioactive, and cost-effective diagnostic tool. The method analyzes abnormal inherent weakness in tissues, change in color and patterns, of a specific region of iris that responds to impulses of heart organ as per Bernard Jensen-iris Chart. The changes in iris infer the presence of degenerative abnormalities in heart organ. These changes are precisely detected and analyzed by IFB method that includes, tensor-based-gradient(TBG), multi orientations gabor filters(GF), textural oriented features(TOF), and speed-up robust features(SURF). Kernel and Multi class oriented support vector machines classifiers are used for classifying normal and pathological iris features. Experimental results demonstrated that the proposed method, not only has better diagnostic performance, but also provides an insight for early detection of other diseases.

Effective Solar Indices for Ionospheric Modeling: A Review and a Proposal for a Real-Time Regional IRI

NASA Astrophysics Data System (ADS)

Pignalberi, A.; Pezzopane, M.; Rizzi, R.; Galkin, I.

2018-01-01

The first part of this paper reviews methods using effective solar indices to update a background ionospheric model focusing on those employing the Kriging method to perform the spatial interpolation. Then, it proposes a method to update the International Reference Ionosphere (IRI) model through the assimilation of data collected by a European ionosonde network. The method, called International Reference Ionosphere UPdate (IRI UP), that can potentially operate in real time, is mathematically described and validated for the period 9-25 March 2015 (a time window including the well-known St. Patrick storm occurred on 17 March), using IRI and IRI Real Time Assimilative Model (IRTAM) models as the reference. It relies on foF2 and M(3000)F2 ionospheric characteristics, recorded routinely by a network of 12 European ionosonde stations, which are used to calculate for each station effective values of IRI indices IG_{12} and R_{12} (identified as IG_{{12{eff}}} and R_{{12{eff}}}); then, starting from this discrete dataset of values, two-dimensional (2D) maps of IG_{{12{eff}}} and R_{{12{eff}}} are generated through the universal Kriging method. Five variogram models are proposed and tested statistically to select the best performer for each effective index. Then, computed maps of IG_{{12{eff}}} and R_{{12{eff}}} are used in the IRI model to synthesize updated values of foF2 and hmF2. To evaluate the ability of the proposed method to reproduce rapid local changes that are common under disturbed conditions, quality metrics are calculated for two test stations whose measurements were not assimilated in IRI UP, Fairford (51.7°N, 1.5°W) and San Vito (40.6°N, 17.8°E), for IRI, IRI UP, and IRTAM models. The proposed method turns out to be very effective under highly disturbed conditions, with significant improvements of the foF2 representation and noticeable improvements of the hmF2 one. Important improvements have been verified also for quiet and moderately disturbed conditions. A visual analysis of foF2 and hmF2 maps highlights the ability of the IRI UP method to catch small-scale changes occurring under disturbed conditions which are not seen by IRI.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwak, Hannah; Chae, Jongchul; Song, Donguk

We report three-minute oscillations in the solar chromosphere driven by a strong downflow event in a sunspot. We used the Fast Imaging Solar Spectrograph of the 1.6 m New Solar Telescope and the Interface Region Imaging Spectrograph (IRIS). The strong downflow event is identified in the chromospheric and transition region lines above the sunspot umbra. After the event, oscillations occur at the same region. The amplitude of the Doppler velocity oscillations is 2 km s{sup −1} and gradually decreases with time. In addition, the period of the oscillations gradually increases from 2.7 to 3.3 minutes. In the IRIS 1330 Åmore » slit-jaw images, we identify a transient brightening near the footpoint of the downflow detected in the H α +0.5 Å image. The characteristics of the downflowing material are consistent with those of sunspot plumes. Based on our findings, we suggest that the gravitationally stratified atmosphere came to oscillate with a three-minute period in response to the impulsive downflow event as was theoretically investigated by Chae and Goode.« less

Remote Sensing of Ionosphere by IONOLAB Group

NASA Astrophysics Data System (ADS)

Arikan, Feza

2016-07-01

Ionosphere is a temporally and spatially varying, dispersive, anisotropic and inhomogeneous medium that is characterized primarily by its electron density distribution. Electron density is a complex function of spatial and temporal variations of solar, geomagnetic, and seismic activities. Ionosphere is the main source of error for navigation and positioning systems and satellite communication. Therefore, characterization and constant monitoring of variability of the ionosphere is of utmost importance for the performance improvement of these systems. Since ionospheric electron density is not a directly measurable quantity, an important derivable parameter is the Total Electron Content (TEC), which is used widely to characterize the ionosphere. TEC is proportional to the total number of electrons on a line crossing the atmosphere. IONOLAB is a research group is formed by Hacettepe University, Bilkent University and Kastamonu University, Turkey gathered to handle the challenges of the ionosphere using state-of-the-art remote sensing and signal processing techniques. IONOLAB group provides unique space weather services of IONOLAB-TEC, International Reference Ionosphere extended to Plasmasphere (IRI-Plas) model based IRI-Plas-MAP, IRI-Plas-STEC and Online IRI-Plas-2015 model at www.ionolab.org. IONOLAB group has been working for imaging and monitoring of ionospheric structure for the last 15 years. TEC is estimated from dual frequency GPS receivers as IONOLAB-TEC using IONOLAB-BIAS. For high spatio-temporal resolution 2-D imaging or mapping, IONOLAB-MAP algorithm is developed that uses automated Universal Kriging or Ordinary Kriging in which the experimental semivariogram is fitted to Matern Function with Particle Swarm Optimization (PSO). For 3-D imaging of ionosphere and 1-D vertical profiles of electron density, state-of-the-art IRI-Plas model based IONOLAB-CIT algorithm is developed for regional reconstruction that employs Kalman Filters for state/temporal transition. IONOLAB group contributes to remote sensing of upper atmosphere, ionosphere and plasmasphere with continuing TUBITAK projects. IONOLAB group is open to joint research and collaboration with researchers from all disciplines that investigate the challenges of ionosphere and space weather. This study is supported by TUBITAK 114E541, 115E915 and Joint TUBITAK 114E092 and AS CR 14/001 projects.

Photographic photometry with Iris diaphragm photometers

NASA Technical Reports Server (NTRS)

Schaefer, B. E.

1981-01-01

A general method is presented for solving problems encountered in the analysis of Iris diaphragm photometer (IDP) data. The method is used to derive the general shape of the calibration curve, allowing both a more accurate fit to the IDP data for comparison stars and extrapolation to magnitude ranges for which no comparison stars are measured. The profile of starlight incident and the characteristic curve of the plate are both assumed and then used to derive the profile of the star image. An IDP reading is then determined for each star image. A procedure for correcting the effects of a nonconstant background fog level on the plate is also demonstrated. Additional applications of the method are made in the appendix to determine the relation between the radius of a photographic star image and the star's magnitude, and to predict the IDP reading of the 'point of optimum density'.

Morphology and Neurochemistry of Rabbit Iris Innervation

PubMed Central

He, Jiucheng; Bazan, Haydee E.P.

2016-01-01

The aim of this study was to map the entire nerve architecture and sensory neuropeptide content of the rabbit iris. Irises from New Zealand rabbits were stained with antibodies against neuronal-class βIII-tubulin, calcitonin gene-related peptide (CGRP) and substance P (SP), and whole-mount images were acquired to build a two-dimensional view of the iridal nerve architecture. After taking images in time-lapse mode, we observed thick nerves running in the iris stroma close to the anterior epithelia, forming four to five stromal nerve rings from the iris periphery to the pupillary margin and sub-branches that connected with each other, constituting the stromal nerve plexus. In the anterior side, fine divisions derivated from the stromal nerves, forming a nerve network-like structure to innervate the superficial anterior border layer, with the pupillary margin having the densest innervation. In the posterior side, the nerve bundles ran along with the pupil dilator muscle in a radial pattern. The morphology of the iris nerves on both sides changed with pupil size. To obtain the relative content of the neuropeptides in the iris, the specimens were double stained with βIII-tubulin and CGRP or SP antibodies. Relative nerve fiber densities for each fiber population were assessed quantitatively by computer-assisted analysis. On the anterior side, CGRP-positive nerve fibers constituted about 61%, while SP-positive nerves constitute about 30.5%, of the total nerve content, which was expressed as βIII tubulin-positive fibers. In addition, in the anterior stroma of the collarette region, there were non-neuronal cells that were positive for SP. On the posterior side, CGRP-positive nerve fibers were about 69% of total nerve content, while SP constituted only up to 20%. Similarly, in the trigeminal ganglia (TG), the number of CGRP-positive neurons significantly outnumbered those that were positive for SP. Also, all the SP-positive neurons were labeled with CGRP. This is the first study to provide a two-dimensional whole mount and a cross-sectional view of the entire iris nerve architecture. Considering the anatomical location, the high expression of CGRP and SP suggests that these neuropeptides may play a role in the pathogenesis of anterior uveitis, glaucoma, cataracts and chronic ocular pain. PMID:25752697

Morphology and neurochemistry of rabbit iris innervation.

PubMed

He, Jiucheng; Bazan, Haydee E P

2015-06-01

The aim of this study was to map the entire nerve architecture and sensory neuropeptide content of the rabbit iris. Irises from New Zealand rabbits were stained with antibodies against neuronal-class βIII-tubulin, calcitonin gene-related peptide (CGRP) and substance P (SP), and whole-mount images were acquired to build a two-dimensional view of the iridal nerve architecture. After taking images in time-lapse mode, we observed thick nerves running in the iris stroma close to the anterior epithelia, forming four to five stromal nerve rings from the iris periphery to the pupillary margin and sub-branches that connected with each other, constituting the stromal nerve plexus. In the anterior side, fine divisions derivated from the stromal nerves, forming a nerve network-like structure to innervate the superficial anterior border layer, with the pupillary margin having the densest innervation. In the posterior side, the nerve bundles ran along with the pupil dilator muscle in a radial pattern. The morphology of the iris nerves on both sides changed with pupil size. To obtain the relative content of the neuropeptides in the iris, the specimens were double stained with βIII-tubulin and CGRP or SP antibodies. Relative nerve fiber densities for each fiber population were assessed quantitatively by computer-assisted analysis. On the anterior side, CGRP-positive nerve fibers constituted about 61%, while SP-positive nerves constitute about 30.5%, of the total nerve content, which was expressed as βIII tubulin-positive fibers. In addition, in the anterior stroma of the collarette region, there were non-neuronal cells that were positive for SP. On the posterior side, CGRP-positive nerve fibers were about 69% of total nerve content, while SP constituted only up to 20%. Similarly, in the trigeminal ganglia (TG), the number of CGRP-positive neurons significantly outnumbered those that were positive for SP. Also, all the SP-positive neurons were labeled with CGRP. This is the first study to provide a two-dimensional whole mount and a cross-sectional view of the entire iris nerve architecture. Considering the anatomical location, the high expression of CGRP and SP suggests that these neuropeptides may play a role in the pathogenesis of anterior uveitis, glaucoma, cataracts and chronic ocular pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluid and structure coupling analysis of the interaction between aqueous humor and iris.

PubMed

Wang, Wenjia; Qian, Xiuqing; Song, Hongfang; Zhang, Mindi; Liu, Zhicheng

2016-12-28

Glaucoma is the primary cause of irreversible blindness worldwide associated with high intraocular pressure (IOP). Elevated intraocular pressure will affect the normal aqueous humor outflow, resulting in deformation of iris. However, the deformation ability of iris is closely related to its material properties. Meanwhile, the passive deformation of the iris aggravates the pupillary block and angle closure. The nature of the interaction mechanism of iris deformation and aqueous humor fluid flow has not been fully understood and has been somewhat a controversial issue. The purpose here was to study the effect of IOP, localization, and temperature on the flow of the aqueous humor and the deformation of iris interacted by aqueous humor fluid flow. Based on mechanisms of aqueous physiology and fluid dynamics, 3D model of anterior chamber (AC) was constructed with the human anatomical parameters as a reference. A 3D idealized standard geometry of anterior segment of human eye was performed. Enlarge the size of the idealization geometry model 5 times to create a simulation device by using 3D printing technology. In this paper, particle image velocimetry technology is applied to measure the characteristic of fluid outflow in different inlet velocity based on the device. Numerically calculations were made by using ANSYS 14.0 Finite Element Analysis. Compare of the velocity distributions to confirm the validity of the model. The fluid structure interaction (FSI) analysis was carried out in the valid geometry model to study the aqueous flow and iris change. In this paper, the validity of the model is verified through computation and comparison. The results indicated that changes of gravity direction of model significantly affected the fluid dynamics parameters and the temperature distribution in anterior chamber. Increased pressure and the vertical position increase the velocity of the aqueous humor fluid flow, with the value increased of 0.015 and 0.035 mm/s. The results act on the iris showed that, gravity direction from horizontal to vertical decrease the equivalent stress in the normal IOP model, while almost invariably in the high IOP model. With the increased of the iris elasticity modulus, the equivalent strain and the total deformation of iris is decreased. The maximal value of equivalent strain of iris in high IOP model is higher than that of in normal IOP model. The maximum deformation of iris is lower in the high IOP model than in the normal IOP model. The valid model of idealization geometry of human eye could be helpful to study the relationship between localization, iris deformation and IOP. So far the FSI analysis was carried out in that idealization geometry model of anterior segment to study aqueous flow and iris change.

Current progress on GSN data quality evaluation

NASA Astrophysics Data System (ADS)

Davis, J. P.; Gee, L. S.; Anderson, K. R.; Ahern, T. K.

2012-12-01

We discuss ongoing work to assess and improve the quality of data collected from instruments deployed at the 150+ stations of the Global Seismographic Network (GSN). The USGS and the IRIS Consortium are coordinating efforts to emphasize data quality following completion of the major installation phase of the GSN and recapitalization of the network's data acquisition systems, ancillary equipment and many of the secondary seismic sensors. We highlight here procedures adopted by the network's operators, the USGS' Albuquerque Seismological Laboratory (ASL) and UCSD's Project IDA, to ensure that the quality of the waveforms collected is maximized, that published metadata accurately reflect the instrument response of the data acquisitions systems, and that the data users are informed of the status of the GSN data quality. Additional details can be found at the GSN Quality webpage (www.iris.edu/hq/programs/gsn/quality). The GSN network operation teams meet frequently to share information and techniques. While custom software developed by each network operator to identify and track known problems remains important, recent efforts are providing new resources and tools to evaluate waveform quality, including analysis provided by the Lamont Waveform Quality Center (www.ldeo.columbia.edu/~ekstrom/Projects/WQC.html) and synthetic seismograms made available through Princeton University's Near Real Time Global Seismicity Portal ( http://global.shakemovie.princeton.edu/home.jsp ) and developments such as the IRIS DMS's MUSTANG and the ASL's Data Quality Analyzer. We conclude with the concept of station certification, a comprehensive overview of a station's performance that we have developed to communicate to data users the state of data- and metadata quality. As progress is made to verify the response and performance of existing systems as well as analysis of past calibration signals and waveform data, we will update information on the GSN web portals to apprise users of the condition of each GSN station's data.

Water Quality Instructional Resources Information System (IRIS): A Compilation of Abstracts to Water Quality and Water Resources Materials, Supplement 30, 1987.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus, OH. Information Reference Center for Science, Mathematics, and Environmental Education.

The Environmental Quality Instructional Resources Center acquires, reviews, indexes, and announces both print (books, modules, units, etc.) and non-print (films, slides, video tapes, etc.) materials related to water quality and water resources education and instruction. This publication contains abstracts and indexes to selected materials related…

Novel Molecular Imaging Approach for Subclinical Detection of Iritis and Evaluation of Therapeutic Success

PubMed Central

Xie, Fang; Sun, Dawei; Schering, Alexander; Nakao, Shintaro; Zandi, Souska; Liu, Ping; Hafezi-Moghadam, Ali

2010-01-01

There is an urgent need for early diagnosis in medicine, whereupon effective treatments could prevent irreversible tissue damage. Acute anterior chamber inflammation is the most common form of uveitis and a major cause of vision loss. The proximity of the iris vasculature to the light-permeable cornea and its involvement in ocular inflammation make it an ideal target for noninvasive molecular imaging. To accomplish this, carboxylated fluorescent microspheres (MSs) were conjugated with recombinant P-selectin glycoprotein ligand-1 and systemically injected in endotoxin-induced uveitic animals. MS adhesion in the microcirculation of the anterior and posterior chamber was visualized by intravital microscopy and scanning laser ophthalmoscopy. In iritic animals, significantly higher numbers of recombinant P-selectin glycoprotein ligand-1-conjugated MSs adhered to the endothelium (P = 0.03) matching the increase in leukocyte adhesion. Conjugated MSs specifically interacted with firmly adhering leukocytes, allowing quantification of the endogenous immune response. Topical eye drop treatment with dexamethasone (P < 0.01) or cyclosporine A (P < 0.01) significantly lowered MS adhesion in iris vessels. Surprisingly, topical dexamethasone significantly reduced MS interaction in the fundus vessels (P < 0.01), while cyclosporine A did not. In vivo MS accumulation preceded clinical signs of anterior uveitis and leukocyte adhesion in iris vasculature. This work introduces noninvasive subclinical detection of endothelial injury in the iris vasculature, providing a unique opportunity for quantifying vascular injury and immune response in vivo. PMID:20581051

Oscillations in the 45 - 5000 MHz Radio Spectrum of the 18 April 2014 Flare

NASA Astrophysics Data System (ADS)

Karlický, Marian; Rybák, Ján; Monstein, Christian

2017-07-01

Using a new type of oscillation map, made from the radio spectra by the wavelet technique, we study the 18 April 2014 M7.3 flare (SOL2014-04-18T13:03:00L245C017). We find a quasi-periodic character of this flare with periods in the range 65 - 115 seconds. At the very beginning of this flare, in connection with the drifting pulsation structure (plasmoid ejection), we find that the 65 - 115 s oscillation phase slowly drifts towards lower frequencies, which indicates an upward propagating wave initiated at the start of the magnetic reconnection. Many periods (1 - 200 seconds) are found in the drifting pulsation structure, which documents multi-scale and multi-periodic processes. On this drifting structure, fiber bursts with a characteristic period of about one second are superimposed, whose frequency drift is similar to that of the drifting 65 - 115 s oscillation phase. We also checked periods found in this flare by the EUV Imaging Spectrometer (EIS)/ Hinode and Interface Region Imaging Spectrograph (IRIS) observations. We recognize the type III bursts (electron beams) as proposed, but their time coincidence with the EIS and IRIS peaks is not very good. The reason probably is that the radio spectrum is a whole-disk record consisting of all bursts from any location, while the EIS and IRIS peaks are emitted only from locations of slits in the EIS and IRIS observations.

12 CFR 1022.3 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... fingerprint, voice print, retina or iris image, or other unique physical representation; (3) Unique electronic... reporting agency to require additional documentation or information, such as a notarized affidavit. (j...

12 CFR 1022.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... fingerprint, voice print, retina or iris image, or other unique physical representation; (3) Unique electronic... reporting agency to require additional documentation or information, such as a notarized affidavit. (j...

Local earthquake interferometry of the IRIS Community Wavefield Experiment, Grant County, Oklahoma

NASA Astrophysics Data System (ADS)

Eddy, A. C.; Harder, S. H.

2017-12-01

The IRIS Community Wavefield Experiment was deployed in Grant County, located in north central Oklahoma, from June 21 to July 27, 2016. Data from all nodes were recorded at 250 samples per second between June 21 and July 20 along three lines. The main line was 12.5 km long oriented east-west and consisted of 129 nodes. The other two lines were 5.5 km long north-south oriented with 49 nodes each. During this time, approximately 150 earthquakes of magnitude 1.0 to 4.4 were recorded in the surrounding counties of Oklahoma and Kansas. Ideally, sources for local earthquake interferometry should be near surface events that produce high frequency body waves. Unlike ambient noise seismic interferometry (ANSI), which uses days, weeks, or even months of continuously recorded seismic data, local earthquake interferometry uses only short segments ( 2 min.) of data. Interferometry in this case is based on the cross-correlation of body wave surface multiples where the event source is translated to a reference station in the array, which acts as a virtual source. Multiples recorded between the reference station and all other stations can be cross-correlated to produce a clear seismic trace. This process will be repeated with every node acting as the reference station for all events. The resulting shot gather will then be processed and analyzed for quality and accuracy. Successful application of local earthquake interferometry will produce a crustal image with identifiable sedimentary and basement reflectors and possibly a Moho reflection. Economically, local earthquake interferometry could lower the time and resource cost of active and passive seismic surveys while improving subsurface image quality in urban settings or areas of limited access. The applications of this method can potentially be expanded with the inclusion of seismic events with a magnitude of 1.0 or lower.

Changes of the eye optics after iris constriction☆

PubMed Central

Montés-Micó, Robert; Hernández, Patricio; Fernández-Sánchez, Vicente; Bonaque, Sergio; Lara, Francisco; López-Gil, Norberto

2011-01-01

Purpose To evaluate the possible change in the optics of the human eye after iris constriction. Methods Ocular aberrations were measured under natural viewing conditions in 26 eyes. The measured eyes fixated on a dim target while the contralateral eye was either occluded (so the measured eye had a large pupil) or highly illuminated (so the measured eye had a small pupil). The measured eyes fixated to a dim target placed 0.5 D beyond the subject’s far point. Zernike values obtained in both situations were compared within the same pupil diameter corresponding to the one obtained under the high illumination condition. Results Significant variation in some aberration coefficients were found between the two illumination conditions. Specially, spherical aberration (SA) increased significantly after pupil miosis (P = .0017). The mean increase of SA measured was 0.018 microns, for a 3-mm pupil. Mean values of other ocular aberrations also vary significantly after pupil miosis (changes were larger than the standard deviation of the repeated measurements). A mean paraxial hyperopic shift of one third of diopter was found after iris constriction. Conclusion Iris constriction slightly modifies the optics of the eye. The small hyperopic shift of the best image plane after iris constriction may be explained by a change in the lens shape and/or position.

Photoacoustic imaging for assessing ischemic kidney damage in vivo

NASA Astrophysics Data System (ADS)

Berndl, Elizabeth S. L.; He, Xiaolin; Yuen, Darren A.; Kolios, Michael C.

2018-02-01

Ischemic reperfusion injuries (IRIs) occur after blood returns to a tissue or organ after a period without oxygen or nutrients, which causes an inflammatory response leading to heterogeneous scarring of the nearby tissue and vasculature. This is associated with long-term decreases blood flow, and necrosis. Although most commonly associated with heart attacks and strokes, IRIs are also a side effect of organ transplants, when the organ is reperfused in the recipient's body after being transported from the donor to the transplant hospital. Currently, the optimal method of monitoring for IRI is limited to biopsies, which are invasive and poorly monitor the spatial heterogeneity of the damage. To non-invasively identify changes in kidneys, the left renal artery in mice (n=3) was clamped for 45 minutes to create an IRI event. Both kidneys of each animal were monitored using photoacoustics (PA) with the VevoLAZR system (Fujifilm-VisualSonics, Toronto) three, four and eight weeks after surgery. IRI-treated kidneys show increased picosirius red staining, indicative of collagen (0.601 vs 0.042, p < 0.0001), decreased size as assessed by cross-sectional area (7.8 mm2 vs 35.9 mm2 , p < 0.0001), and decreased oxygen saturation (sO2; 62% vs 77%, p = 0.02). Analysis of the photoacoustic data shows that a two-point metric, the 715:930 nm ratio of the whole kidney (1.05 vs 0.57, p = 0.049) and the optical spectral slope (OSS) (0.8 * 10-3 vs 3.0 * 10-3, p = 0.013) are both able to differentiate between IRI-treated and healthy kidneys. These data suggest that photoacoustics can be used as a non-invasive method to observe in vivo changes in the kidney due to IRI.

Inability to perform posterior segment monitoring by scanning laser ophthalmoscopy or optical coherence tomography with some occlusive intraocular lenses in clinical use.

PubMed

Yusuf, Imran H; Peirson, Stuart N; Patel, Chetan K

2012-03-01

To evaluate whether occlusive intraocular lenses (IOLs) produced by several manufacturers for clinical use equivalently transmit near-infrared (IR) light for scanning laser ophthalmoscopy (SLO) or optical coherence tomography (OCT) imaging. Nuffield Laboratory of Ophthalmology, Oxford University, United Kingdom. Evaluation of diagnostic test or technology. The study evaluated 6 black IOLs of 2 designs: 3 poly(methyl methacrylate) (PMMA) and 3 iris-claw anterior chamber IOLs. Each IOL was placed between a broad-spectrum white light source and a spectroradiometer to generate transmission spectra. Transmission in the near-IR range was examined using an 850 nm light-emitting diode. Scanning laser ophthalmoscopy or OCT imaging using Spectralis spectral-domain SLO or OCT was attempted through occlusive IOLs in a model eye. Artisan iris-claw and MS 612 PMMA occlusive IOLs totally occluded all wavelengths of light, including in the near IR range in which SLO and OCT imaging systems operate. It was not possible to capture SLO or OCT images through the iris-claw and PMMA occlusive IOLs in a model eye. Results suggest the property of near-IR transmission that permits SLO or OCT imaging through occlusive IOLs is restricted to the Morcher range of occlusive IOLs. Patients with non-near IR transmitting IOLs will not be able to receive detailed posterior segment monitoring with SLO or OCT. This finding may have a significant impact on preoperative occlusive IOL selection and the management of current patients with occlusive IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

ON THE ACTIVE REGION BRIGHT GRAINS OBSERVED IN THE TRANSITION REGION IMAGING CHANNELS OF IRIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skogsrud, H.; Voort, L. Rouppe van der; Pontieu, B. De

The Interface Region Imaging Spectrograph (IRIS) provides spectroscopy and narrow band slit-jaw (SJI) imaging of the solar chromosphere and transition region at unprecedented spatial and temporal resolutions. Combined with high-resolution context spectral imaging of the photosphere and chromosphere as provided by the Swedish 1 m Solar Telescope (SST), we can now effectively trace dynamic phenomena through large parts of the solar atmosphere in both space and time. IRIS SJI 1400 images from active regions, which primarily sample the transition region with the Si iv 1394 and 1403 Å lines, reveal ubiquitous bright “grains” which are short-lived (two to five minute)more » bright roundish small patches of sizes 0.″5–1.″7 that generally move limbward with velocities up to about 30 km s{sup −1}. In this paper, we show that many bright grains are the result of chromospheric shocks impacting the transition region. These shocks are associated with dynamic fibrils (DFs), most commonly observed in Hα. We find that the grains show the strongest emission in the ascending phase of the DF, that the emission is strongest toward the top of the DF, and that the grains correspond to a blueshift and broadening of the Si iv lines. We note that the SJI 1400 grains can also be observed in the SJI 1330 channel which is dominated by C ii lines. Our observations show that a significant part of the active region transition region dynamics is driven from the chromosphere below rather than from coronal activity above. We conclude that the shocks that drive DFs also play an important role in the heating of the upper chromosphere and lower transition region.« less

On the Origin of the Flare Emission in IRIS ’ SJI 2832 Filter:Balmer Continuum or Spectral Lines?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleint, Lucia; Krucker, Säm; Heinzel, Petr

Continuum (“white-light,” WL) emission dominates the energetics of flares. Filter-based observations, such as the IRIS SJI 2832 filter, show WL-like brightenings during flares, but it is unclear whether the emission arises from real continuum emission or enhanced spectral lines, possibly turning into emission. The difficulty in filter-based observations, contrary to spectral observations, is to determine which processes contribute to the observed brightening during flares. Here we determine the contribution of the Balmer continuum and the spectral line emission to IRIS ’ SJI 2832 emission by analyzing the appropriate passband in simultaneous IRIS NUV spectra. We find that spectral line emissionmore » can contribute up to 100% to the observed slitjaw images (SJI) emission, that the relative contributions usually temporally vary, and that the highest SJI enhancements that are observed are most likely because of the Balmer continuum. We conclude that care should be taken when calling SJI 2832 a continuum filter during flares, because the influence of the lines on the emission can be significant.« less

Privacy information management for video surveillance

NASA Astrophysics Data System (ADS)

Luo, Ying; Cheung, Sen-ching S.

2013-05-01

The widespread deployment of surveillance cameras has raised serious privacy concerns. Many privacy-enhancing schemes have been proposed to automatically redact images of trusted individuals in the surveillance video. To identify these individuals for protection, the most reliable approach is to use biometric signals such as iris patterns as they are immutable and highly discriminative. In this paper, we propose a privacy data management system to be used in a privacy-aware video surveillance system. The privacy status of a subject is anonymously determined based on her iris pattern. For a trusted subject, the surveillance video is redacted and the original imagery is considered to be the privacy information. Our proposed system allows a subject to access her privacy information via the same biometric signal for privacy status determination. Two secure protocols, one for privacy information encryption and the other for privacy information retrieval are proposed. Error control coding is used to cope with the variability in iris patterns and efficient implementation is achieved using surrogate data records. Experimental results on a public iris biometric database demonstrate the validity of our framework.

Extended depth of field in an intrinsically wavefront-encoded biometric iris camera

NASA Astrophysics Data System (ADS)

Bergkoetter, Matthew D.; Bentley, Julie L.

2014-12-01

This work describes a design process which greatly increases the depth of field of a simple three-element lens system intended for biometric iris recognition. The system is optimized to produce a point spread function which is insensitive to defocus, so that recorded images may be deconvolved without knowledge of the exact object distance. This is essentially a variation on the technique of wavefront encoding, however the desired encoding effect is achieved by aberrations intrinsic to the lens system itself, without the need for a pupil phase mask.

Water Quality Instructional Resources Information System (IRIS): A Compilation of Abstracts to Water Quality and Water Resources materials. Supplement 31, 1987.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus, OH. Information Reference Center for Science, Mathematics, and Environmental Education.

The Environmental Quality Instructional Resources Center in Columbus, Ohio, acquires, reviews, indexes, and announces both print (books, modules, units, etc.) and non-print (films, slides, video tapes, etc.) materials related to water quality and water resources education and instruction. This publication contains abstracts and indexes to selected…

Water Quality Instructional Resources Information System (IRIS): A Compilation of Abstracts to Water Quality and Water Resources Materials. Supplement 33, 1988.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus, OH. Information Reference Center for Science, Mathematics, and Environmental Education.

The Environmental Quality Instructional Resources Center in Columbus, Ohio, acquires, reviews, indexes, and announces both print (books, modules, units, etc.) and non-print (films, slides, video tapes, etc.) materials related to water quality and water resources education and instruction. In addition some materials related to hazardous materials,…

Water Quality Instructional Resources Information System (IRIS): A Compilation of Abstracts to Water Quality and Water Resources Materials. Supplement 32, 1987.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus, OH. Information Reference Center for Science, Mathematics, and Environmental Education.

The Environmental Quality Instructional Resources Center in Columbus, Ohio, acquires, reviews, indexes, and announces both print (books, modules, units, etc.) and non-print (films, slides, video tapes, etc.) materials related to water quality and water resources education and instruction. In addition some materials related to pesticides, hazardous…

Water Quality Instructional Resources Information System (IRIS): A Compilation of Abstracts to Water Quality and Water Resources Materials. Supplement 34, 1988.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus, OH. Information Reference Center for Science, Mathematics, and Environmental Education.

The Environmental Quality Instructional Resources Center in Columbus, Ohio, acquires, reviews, indexes, and announces both print (books, modules, units, etc.) and non-print (films, slides, video tapes, etc.) materials related to water quality and water resources education and instruction. In addition some materials related to pesticides, hazardous…

The GSN Data Quality Initiative

NASA Astrophysics Data System (ADS)

Davis, J. P.; Anderson, K. R.; Gee, L. S.

2010-12-01

The Global Seismographic Network (GSN) is undertaking a renewed effort to assess and assure data quality that builds upon completion of the major installation phase of the GSN and recent funding to recapitalize most of the network’s equipment including data acquisition systems, ancillary equipment and secondary sensors. We highlight here work by the network operators, the USGS’ Albuquerque Seismological Lab and UCSD’s Project IDA, to ensure that both the quality of the waveforms collected is maximized, that the published metadata accurately reflect the instrument response of the data acquisitions systems, and that data users are informed of the status of the GSN data quality. Procedures to evaluate waveform quality blend tools made available through the IRIS DMC’s Quality Analysis Control Kit (http://www.iris.washington.edu/QUACK/), analysis results provided by the Lamont Waveform Quality Center (www.ldeo.columbia.edu/~ekstrom/Projects/WQC.html), and custom software developed by each of the operators to identify and track known hardware failure modes. Each operator’s equipment upgrade schedule is updated periodically to address sensors identified as failing or problematic and for which replacements are available. Particular attention is also paid to monitoring the GPS clock signal to guarantee that the data are timed properly. Devices based on GPS technology unavailable when the GSN began 25 years ago are being integrated into operations to verify sensor orientations. Portable, broadband seismometers whose stable response can be verified in the laboratory are now co-located with GSN sensors during field visits to verify the existing GSN sensors’ sensitivity. Additional effort is being made to analyze past calibration signals and to check the system response functions of the secondary broadband sensors at GSN sites. The new generation of data acquisition systems will enable relative calibrations to be performed more frequently than was possible in the past. Additional details of this effort can be found at the GSN Quality webpage (www.iris.edu/hq/programs/gsn/quality).

IRIS Ultraviolet Spectral Properties of a Sample of X-Class Solar Flares

NASA Astrophysics Data System (ADS)

Butler, Elizabeth; Kowalski, Adam; Cauzzi, Gianna; Allred, Joel C.; Daw, Adrian N.

2018-06-01

The white-light (near-ultraviolet (NUV) and optical) continuum emission comprises the majority of the radiated energy in solar flares. However, there are nearly as many explanations for the origin of the white-light continuum radiation as there are white-light flares that have been studied in detail with spectra. Furthermore, there are rarely robust constraints on the time-resolved dynamics in the white-light emitting flare layers. We are conducting a statistical study of the properties of Fe II lines, Mg II lines, and NUV continuum intensity in bright flare kernels observed by the Interface Region Imaging Spectrograph (IRIS), in order to provide comprehensive constraints for radiative-hydrodynamic flare models. Here we present a new technique for identifying bright flare kernels and preliminary relationships among IRIS spectral properties for a sample of X-class solar flares.

Hi-C OBSERVATIONS OF SUNSPOT PENUMBRAL BRIGHT DOTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alpert, Shane E.; Tiwari, Sanjiv K.; Moore, Ronald L.

We report observations of bright dots (BDs) in a sunspot penumbra using High Resolution Coronal Imager (Hi-C) data in 193 Å and examine their sizes, lifetimes, speeds, and intensities. The sizes of the BDs are on the order of 1″ and are therefore hard to identify in the Atmospheric Imaging Assembly (AIA) 193 Å images, which have a 1.″2 spatial resolution, but become readily apparent with Hi-C's spatial resolution, which is five times better. We supplement Hi-C data with data from AIA's 193 Å passband to see the complete lifetime of the BDs that appeared before and/or lasted longer thanmore » Hi-C's three-minute observation period. Most Hi-C BDs show clear lateral movement along penumbral striations, either toward or away from the sunspot umbra. Single BDs often interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to have smaller displacements. These BDs are about as numerous but move slower on average than Interface Region Imaging Spectrograph (IRIS) BDs, which was recently reported by Tian et al., and the sizes and lifetimes are on the higher end of the distribution of IRIS BDs. Using additional AIA passbands, we compare the light curves of the BDs to test whether the Hi-C BDs have transition region (TR) temperatures like those of the IRIS BDs. The light curves of most Hi-C BDs peak together in different AIA channels, indicating that their temperatures are likely in the range of the cooler TR (1−4 × 10{sup 5} K).« less

Characterization of skin abnormalities in a mouse model of osteogenesis imperfecta using high resolution magnetic resonance imaging and Fourier transform infrared imaging spectroscopy.

PubMed

Canuto, H C; Fishbein, K W; Huang, A; Doty, S B; Herbert, R A; Peckham, J; Pleshko, N; Spencer, R G

2012-01-01

Evaluation of the skin phenotype in osteogenesis imperfecta (OI) typically involves biochemical measurements, such as histologic or biochemical assessment of the collagen produced from biopsy-derived dermal fibroblasts. As an alternative, the current study utilized non-invasive magnetic resonance imaging (MRI) microscopy and optical spectroscopy to define biophysical characteristics of skin in an animal model of OI. MRI of skin harvested from control, homozygous oim/oim and heterozygous oim/+ mice demonstrated several differences in anatomic and biophysical properties. Fourier transform infrared imaging spectroscopy (FT-IRIS) was used to interpret observed MRI signal characteristics in terms of chemical composition. Differences between wild-type and OI mouse skin included the appearance of a collagen-depleted lower dermal layer containing prominent hair follicles in the oim/oim mice, accounting for 55% of skin thickness in these. The MRI magnetization transfer rate was lower by 50% in this layer as compared to the upper dermis, consistent with lower collagen content. The MRI transverse relaxation time, T2, was greater by 30% in the dermis of the oim/oim mice compared to controls, consistent with a more highly hydrated collagen network. Similarly, an FT-IRIS-defined measure of collagen integrity was 30% lower in the oim/oim mice. We conclude that characterization of phenotypic differences between the skin of OI and wild-type mice by MRI and FT-IRIS is feasible, and that these techniques provide powerful complementary approaches for the analysis of the skin phenotype in animal models of disease. Copyright © 2011 John Wiley & Sons, Ltd.

Synchronized observations of bright points from the solar photosphere to the corona

NASA Astrophysics Data System (ADS)

Tavabi, Ehsan

2018-05-01

One of the most important features in the solar atmosphere is the magnetic network and its relationship to the transition region (TR) and coronal brightness. It is important to understand how energy is transported into the corona and how it travels along the magnetic field lines between the deep photosphere and chromosphere through the TR and corona. An excellent proxy for transportation is the Interface Region Imaging Spectrograph (IRIS) raster scans and imaging observations in near-ultraviolet (NUV) and far-ultraviolet (FUV) emission channels, which have high time, spectral and spatial resolutions. In this study, we focus on the quiet Sun as observed with IRIS. The data with a high signal-to-noise ratio in the Si IV, C II and Mg II k lines and with strong emission intensities show a high correlation with TR bright network points. The results of the IRIS intensity maps and dopplergrams are compared with those of the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) instruments onboard the Solar Dynamical Observatory (SDO). The average network intensity profiles show a strong correlation with AIA coronal channels. Furthermore, we applied simultaneous observations of the magnetic network from HMI and found a strong relationship between the network bright points in all levels of the solar atmosphere. These features in the network elements exhibited regions of high Doppler velocity and strong magnetic signatures. Plenty of corona bright points emission, accompanied by the magnetic origins in the photosphere, suggest that magnetic field concentrations in the network rosettes could help to couple the inner and outer solar atmosphere.

Topside correction of IRI by global modeling of ionospheric scale height using COSMIC radio occultation data

NASA Astrophysics Data System (ADS)

Wu, M. J.; Guo, P.; Fu, N. F.; Xu, T. L.; Xu, X. S.; Jin, H. L.; Hu, X. G.

2016-06-01

The ionosphere scale height is one of the most significant ionospheric parameters, which contains information about the ion and electron temperatures and dynamics in upper ionosphere. In this paper, an empirical orthogonal function (EOF) analysis method is applied to process all the ionospheric radio occultations of GPS/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) from the year 2007 to 2011 to reconstruct a global ionospheric scale height model. This monthly medium model has spatial resolution of 5° in geomagnetic latitude (-87.5° ~ 87.5°) and temporal resolution of 2 h in local time. EOF analysis preserves the characteristics of scale height quite well in the geomagnetic latitudinal, anural, seasonal, and diurnal variations. In comparison with COSMIC measurements of the year of 2012, the reconstructed model indicates a reasonable accuracy. In order to improve the topside model of International Reference Ionosphere (IRI), we attempted to adopt the scale height model in the Bent topside model by applying a scale factor q as an additional constraint. With the factor q functioning in the exponent profile of topside ionosphere, the IRI scale height should be forced equal to the precise COSMIC measurements. In this way, the IRI topside profile can be improved to get closer to the realistic density profiles. Internal quality check of this approach is carried out by comparing COSMIC realistic measurements and IRI with or without correction, respectively. In general, the initial IRI model overestimates the topside electron density to some extent, and with the correction introduced by COSMIC scale height model, the deviation of vertical total electron content (VTEC) between them is reduced. Furthermore, independent validation with Global Ionospheric Maps VTEC implies a reasonable improvement in the IRI VTEC with the topside model correction.

Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases.

PubMed

Jang, Si Young; Lalonde, Ron; Ozhasoglu, Cihat; Burton, Steven; Heron, Dwight; Huq, M Saiful

2016-09-08

We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty-four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study. Treatment plans were generated for all lesions using the InCise MLC. Number of monitor units, delivery time, target coverage, conformity index, and dose falloff were compared between MLC- and clinical cone/Iris-based plans. Statistical analysis was performed using the non-parametric Wilcoxon-Mann-Whitney signed-rank test. The planning accuracy of the MLC-based plans was validated using chamber and film measurements. The InCise MLC-based plans achieved mean dose and target coverage comparable to the cone/Iris-based plans. Although the conformity indices of the MLC-based plans were slightly higher than those of the cone/Iris-based plans, beam delivery time for the MLC-based plans was shorter by 30% ~ 40%. For smaller targets or cases with OARs located close to or abutting target volumes, MLC-based plans provided inferior dose conformity compared to cone/Iris-based plans. The QA results of MLC-based plans were within 5% absolute dose difference with over 90% gamma passing rate using 2%/2 mm gamma criteria. The first version of InCise MLC could be a useful delivery modality, especially for clinical situations for which delivery time is a limiting factor or for multitarget cases. © 2016 The Authors.

Progress Toward an IRIS++ Database Open to the Helioseismological Community

NASA Astrophysics Data System (ADS)

Gelly, B.; Khalikov, S.; Pallé, P. L.; IRIS Team

The IRIS network is now fourteen years old, and has continuously been taking data since 1989. The data analysis, which produced some noticeable scientifical results, like the measurement of the ell = 1 rotationnal splitting or the measurement of the solar acoustic cut-off frequency, was mainly performed with the summer campaigns data of 1989 to 1992. P-mode frequency and width tables were recently published using the same subset of the IRIS data . We are now finishing the calibration and the timing of the whole set of IRIS data from 89 to 97, which will increase by a factor of 4 the amount of available data. The duty cycle of the IRIS network ranges from about 65% over 3 months of the summer campaigns to some 23% over one year in the worst case. To improve our duty cycle we developed several collaborations with other teams running similar instruments: (1) the Mark I instrument, ran at the IAC for many years, a potassium resonance single pixel device, also part of the BiSON network (Elsworth et al., 1988). (2) Alexandro Cacciani's MOF, ran at the JPL in Pasadena. Although this is a sodium resonance imaging instrument, it has been used in ``one pixel'' format for several summer seasons since 1989 (Cacciani et al., 1984). (3) the LOWL instrument is a Doppler imager also based on a Magneto-Optical Filter (MOF), operated at the Mauna Loa solar observatory since 1994 (Tomczyk et al., 1995). The merging of those 'alien' data has been carefully adressed at the calibration ands timing stages, and we can now present the advantages of such a-posteriori collaborations. We endeavour to set-up the corresponding database of 'one-pixel seismological data from ground-based intruments' in Nice and to open it to the scientific community of this meeting by the end of 1998. This database will soon have the potential to trace the spectral features of the solar signal over one 11-years cycle.

Chronic post-operative iris prosthesis endophthalmitis in a patient with traumatic aniridia: a case report.

PubMed

Firl, Kevin C; Montezuma, Sandra R

2016-11-09

Post-operative endophthalmitis is a serious complication of intraocular surgery which may present acutely or chronically. Chronic post-operative endophthalmitis is characterized by decreased visual acuity, mild pain, and low-grade uveitis several weeks or months after intraocular surgery which may be responsive to corticosteroids, but recur upon tapering. Low virulence organisms such as Propionibacterium acnes are the most common culprit organisms, and treatment most often consists of both intravitreal antibiotic injections and surgery. Aniridia is a condition defined by total or partial loss of the iris and leads to decreased visual quality marked by glare and photophobia. Treatment of complex or severe cases of traumatic aniridia in which surgical repair is difficult may consist of implantation of iris prostheses, devices designed to reduce symptoms of aniridia. Though chronic, post-operative endophthalmitis has been associated with most intraocular surgeries including intraocular lens implantation after cataract removal, it has never been described in a patient with an iris prosthesis. In this case report, we describe the case of a 49 year old, male construction worker with traumatic aniridia who experienced chronic, recurrent low-grade intraocular inflammation and irritation for months after implantation of the Ophtec 311 prosthetic iris. Symptoms and signs of inflammation improved temporarily with sub-Tenon's capsule triamcinolone injections. Ultimately after more than 2 post-operative years, the iris prosthesis was explanted, and intravitreal cultures showed P. acnes growth after 5 days. Intravitreal antibiotics treated the infection successfully. To our knowledge, this is the first reported case of chronic, post-operative endophthalmitis in a patient with an iris prosthesis. Chronic, post-operative endophthalmitis may be a difficult to identify in the context of traumatic aniridia and iris prosthesis implantation due to other potential etiologies of chronic intraocular inflammation such as implant-induced chafing. Clinicians should suspect chronic, post-operative endophthalmitis in any case of recurrent, low-grade intraocular inflammation.

Water Quality Instructional Resources Information System (IRIS): A Compilation of Abstracts to Water Quality and Water Resources Materials.

ERIC Educational Resources Information Center

Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

Presented is a compilation of over 3,000 abstracts on print and non-print materials related to water quality and water resources education. Entries are included from all levels of governmental sources, private concerns, and educational institutions. Each entry includes: title, author, cross references, descriptors, and availability. (CLS)

Water Quality Instructional Resources Information System (IRIS): A Compilation of Abstracts to Water Quality and Water Resources Materials. Supplement VIII.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus, OH. Information Reference Center for Science, Mathematics, and Environmental Education.

Compiled are abstracts and indexes to selected print and non-print materials; related to wastewater treatment and water quality education and instruction, as well as materials related to pesticides, hazardous wastes, and public participation. Sources of abstracted/indexed materials include all levels of government, private concerns, and…

Machine learning techniques for medical diagnosis of diabetes using iris images.

PubMed

Samant, Piyush; Agarwal, Ravinder

2018-04-01

Complementary and alternative medicine techniques have shown their potential for the treatment and diagnosis of chronical diseases like diabetes, arthritis etc. On the same time digital image processing techniques for disease diagnosis is reliable and fastest growing field in biomedical. Proposed model is an attempt to evaluate diagnostic validity of an old complementary and alternative medicine technique, iridology for diagnosis of type-2 diabetes using soft computing methods. Investigation was performed over a close group of total 338 subjects (180 diabetic and 158 non-diabetic). Infra-red images of both the eyes were captured simultaneously. The region of interest from the iris image was cropped as zone corresponds to the position of pancreas organ according to the iridology chart. Statistical, texture and discrete wavelength transformation features were extracted from the region of interest. The results show best classification accuracy of 89.63% calculated from RF classifier. Maximum specificity and sensitivity were absorbed as 0.9687 and 0.988, respectively. Results have revealed the effectiveness and diagnostic significance of proposed model for non-invasive and automatic diabetes diagnosis. Copyright © 2018 Elsevier B.V. All rights reserved.

Application of IRI-Plas in Ionospheric Tomography and HF Communication Studies with Assimilation of GPS-TEC

NASA Astrophysics Data System (ADS)

Arikan, Feza; Gulyaeva, Tamara; Sezen, Umut; Arikan, Orhan; Toker, Cenk; Hakan Tuna, MR.; Erdem, Esra

2016-07-01

International Reference Ionosphere is the most acknowledged climatic model of ionosphere that provides electron density profile and hourly, monthly median values of critical layer parameters of the ionosphere for a desired location, date and time between 60 to 2,000 km altitude. IRI is also accepted as the International Standard Ionosphere model. Recently, the IRI model is extended to the Global Positioning System (GPS) satellite orbital range of 20,000 km. The new version is called IRI-Plas and it can be obtained from http://ftp.izmiran.ru/pub/izmiran /SPIM/. A user-friendly online version is also provided at www.ionolab.org as a space weather service. Total Electron Content (TEC), which is defined as the line integral of electron density on a given ray path, is an observable parameter that can be estimated from earth based GPS receivers in a cost-effective manner as GPS-TEC. One of the most important advantages of IRI-Plas is the possible input of GPS-TEC to update the background deterministic ionospheric model to the current ionospheric state. This option is highly useful in regional and global tomography studies and HF link assessments. IONOLAB group currently implements IRI-Plas as a background model and updates the ionospheric state using GPS-TEC in IONOLAB-CIT and IONOLAB-RAY algorithms. The improved state of ionosphere allows the most reliable 4-D imaging of electron density profiles and HF and satellite communication link simulations.This study is supported by TUBITAK 115E915 and joint TUBITAK 114E092 and AS CR 14/001.

Evidence for two-loop interaction from IRIS and SDO observations of penumbral brightenings

NASA Astrophysics Data System (ADS)

Alissandrakis, C. E.; Koukras, A.; Patsourakos, S.; Nindos, A.

2017-07-01

Aims: We investigate small scale energy release events which can provide clues on the heating mechanism of the solar corona. Methods: We analyzed spectral and imaging data from the Interface Region Imaging Spectrograph (IRIS), images from the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatoty (SDO), and magnetograms from the Helioseismic and Magnetic Imager (HMI) aboard SDO. Results: We report observations of small flaring loops in the penumbra of a large sunspot on July 19, 2013. Our main event consisted of a loop spanning 15'', from the umbral-penumbral boundary to an opposite polarity region outside the penumbra. It lasted approximately 10 min with a two minute impulsive peak and was observed in all AIA/SDO channels, while the IRIS slit was located near its penumbral footpoint. Mass motions with an apparent velocity of 100 km s-1 were detected beyond the brightening, starting in the rise phase of the impulsive peak; these were apparently associated with a higher-lying loop. We interpret these motions in terms of two-loop interaction. IRIS spectra in both the C II and Si iv lines showed very extended wings, up to about 400 km s-1, first in the blue (upflows) and subsequently in the red wing. In addition to the strong lines, emission was detected in the weak lines of Cl I, O I and C I, as well as in the Mg II triplet lines. Absorption features in the profiles of the C II doublet, the Si iv doublet and the Mg II h and k lines indicate the existence of material with a lower source function between the brightening and the observer. We attribute this absorption to the higher loop and this adds further credibility to the two-loop interaction hypothesis. Tilts were detected in the absorption spectra, as well as in the spectra of Cl I, O I, and C I lines, possibly indicating rotational motions from the untwisting of magnetic flux tubes. Conclusions: We conclude that the absorption features in the C II, Si iv and Mg II profiles originate in a higher-lying, descending loop; as this approached the already activated lower-lying loop, their interaction gave rise to the impulsive peak, the very broad line profiles and the mass motions. Movies associated to Figs. A.1-A.3 are available at http://www.aanda.org

Deployment of Indicator of Reduction in Soils (IRIS) Probes in Arctic Drained Thaw Lake Basins and Drainages: Time Integrated Signals of Soil Saturation and Redox

NASA Astrophysics Data System (ADS)

Heikoop, J. M.; Newman, B. D.; Hudak, M.; Gard, M.; Altmann, G.; Throckmorton, H.; Wilson, C. J.

2013-12-01

Climate driven warming and degradation of permafrost may lead to changes in the hydrology of low gradient regions like the North Slope of Alaska. Hydrologic changes will affect the saturation and redox state of soils in drained thaw lake basins (DTLBs), interlake areas, and associated drainages. These changes are being investigated at the Barrow Environmental Observatory (BEO) and surroundings as part of the Next Generation Ecosystem Experiment - Arctic project. As a complement to traditional redox and aqueous chemistry measurements, the use of indicator of reduction in soils (IRIS) probes is being assessed as a simple and cost-effective way to monitor redox changes. The probes consist of PVC sheets coated with a ferrihydrite paint. Under reducing conditions iron on these probes will partially dissolve. The amount of dissolution can be quantified by image analysis and related in a semi-quantitative fashion to redox conditions in the soils. IRIS probes have been successfully utilized in numerous temperate settings to demonstrate, for example, the presence of reducing soils for wetlands delineation. Test probes were installed in saturated soils for 48 hours in July, 2013. After 48 hours, minor reductive dissolution of ferrihydrite was observed. No sulfide precipitation was noted. As such, probes were installed in quadruplicate at 14 locations representing primarily outlet drainages from different-aged DTLBs and interlake areas. In each case, the probes were installed to refusal at the frost table within the active layer overlying the permafrost. IRIS probes were deployed adjacent to arrays of rhizon samplers used for soil pore water sampling so that time-integrated IRIS probe results can be compared to chemical results (a snapshot in time) obtained at the beginning and end of the monitoring period (probes will be extracted in September). Image analysis will employ LANL's GENIE technology. Field measurements of ferrous iron in water samples showed significant redox variation both between locations and with depth at each location. Values were lowest in surface waters (as low as zero mg/L) and were generally higher in soil pore water with values up to approximately 7 mg/L. Correlations between percentage iron removal from the IRIS probes and ferrous iron and other redox sensitive species will be presented. If correlations are significant, redox couples (ammonia/nitrate, Fe(II)/Fe(III), sulfide/sulfate) will be used to estimate Eh and to develop an empirical relationship for the use of IRIS probes in the BEO and surrounding environs.

Re: Request for Correction - IRIS Assessment for Trichloroethylene

EPA Pesticide Factsheets

Letter from Faye Graul providing supplemental information to her Request for Correction for Threshold of Trichloroethylene Contamination of Maternal Drinking Waters submitted under the Information Quality Act.

Transillumination of iris and subnormal visual acuity--ocular albinism?

PubMed Central

Sjödell, L.; Sjöström, A.; Abrahamsson, M.

1996-01-01

BACKGROUND: A common clinical sign in children with subnormal visual acuity or slow visual development was iris transillumination. This was used as the inclusion criterion in a study of children shown to have a subnormal visual acuity in a general health examination at age 4 years. METHODS: Refraction values, stereopsis, fundus photography, macular and nerve head appearance, and visual evoked response (VER) recordings were studied in 18 children. The clinical results were compared with 64 controls referred to the eye clinic because of subnormal vision from the general health examination or from school health care. RESULTS: Eight children had VERs showing asymmetry typical for albinism. Another four had only small asymmetries on the VER, indicating a lower degree of decussation abnormality. No simple correlation of visual acuity, degree of iris transillumination, stereopsis, or macular pathology and VER asymmetries were found. However, marked iris transillumination in all four quadrants, absence of a foveal reflex, and low visual acuity were weakly correlated. CONCLUSIONS: In a rather homogeneous group of children with iris transillumination and subnormal visual acuity eight of 18 had typical albino VERs. The findings of small atypical VER asymmetries in four children and no asymmetry in six children suggest that albinism may be considered as a description of a heterogeneous group of conditions including maximal decussation rate (100%) in the chiasma to a condition with almost normal (> or = 50%) decussation rate. Images PMID:8795373