Computer-generated, calligraphic, full-spectrum color system for visual simulation landing approach maneuvers

NASA Technical Reports Server (NTRS)

Chase, W. D.

1975-01-01

The calligraphic chromatic projector described was developed to improve the perceived realism of visual scene simulation ('out-the-window visuals'). The optical arrangement of the projector is illustrated and discussed. The device permits drawing 2000 vectors in as many as 500 colors, all above critical flicker frequencies, and use of high scene resolution and brightness at an acceptable level to the pilot, with the maximum system capabilities of 1000 lines and 1000 fL. The device for generating the colors is discussed, along with an experiment conducted to demonstrate potential improvements in performance and pilot opinion. Current research work and future research plans are noted.

Demonstration of the Wide-Field Imaging Interferometer Testbed Using a Calibrated Hyperspectral Image Projector

NASA Technical Reports Server (NTRS)

Bolcar, Matthew R.; Leisawitz, David; Maher, Steve; Rinehart, Stephen

2012-01-01

The Wide-field Imaging Interferometer testbed (WIIT) at NASA's Goddard Space Flight Center uses a dual-Michelson interferometric technique. The WIIT combines stellar interferometry with Fourier-transform interferometry to produce high-resolution spatial-spectral data over a large field-of-view. This combined technique could be employed on future NASA missions such as the Space Infrared Interferometric Telescope (SPIRIT) and the Sub-millimeter Probe of the Evolution of Cosmic Structure (SPECS). While both SPIRIT and SPECS would operate at far-infrared wavelengths, the WIIT demonstrates the dual-interferometry technique at visible wavelengths. The WIIT will produce hyperspectral image data, so a true hyperspectral object is necessary. A calibrated hyperspectral image projector (CHIP) has been constructed to provide such an object. The CHIP uses Digital Light Processing (DLP) technology to produce customized, spectrally-diverse scenes. CHIP scenes will have approximately 1.6-micron spatial resolution and the capability of . producing arbitrary spectra in the band between 380 nm and 1.6 microns, with approximately 5-nm spectral resolution. Each pixel in the scene can take on a unique spectrum. Spectral calibration is achieved with an onboard fiber-coupled spectrometer. In this paper we describe the operation of the CHIP. Results from the WIIT observations of CHIP scenes will also be presented.

Design of two-DMD based zoom MW and LW dual-band IRSP using pixel fusion

NASA Astrophysics Data System (ADS)

Pan, Yue; Xu, Xiping; Qiao, Yang

2018-06-01

In order to test the anti-jamming ability of mid-wave infrared (MWIR) and long-wave infrared (LWIR) dual-band imaging system, a zoom mid-wave (MW) and long-wave (LW) dual-band infrared scene projector (IRSP) based on two-digital micro-mirror device (DMD) was designed by using a projection method of pixel fusion. Two illumination systems, which illuminate the two DMDs directly with Kohler telecentric beam respectively, were combined with projection system by a spatial layout way. The distances of projection entrance pupil and illumination exit pupil were also analyzed separately. MWIR and LWIR virtual scenes were generated respectively by two DMDs and fused by a dichroic beam combiner (DBC), resulting in two radiation distributions in projected image. The optical performance of each component was evaluated by ray tracing simulations. Apparent temperature and image contrast were demonstrated by imaging experiments. On the basis of test and simulation results, the aberrations of optical system were well corrected, and the quality of projected image meets test requirements.

Advances in iterative non-uniformity correction techniques for infrared scene projection

NASA Astrophysics Data System (ADS)

Danielson, Tom; Franks, Greg; LaVeigne, Joe; Prewarski, Marcus; Nehring, Brian

2015-05-01

Santa Barbara Infrared (SBIR) is continually developing improved methods for non-uniformity correction (NUC) of its Infrared Scene Projectors (IRSPs) as part of its comprehensive efforts to achieve the best possible projector performance. The most recent step forward, Advanced Iterative NUC (AI-NUC), improves upon previous NUC approaches in several ways. The key to NUC performance is achieving the most accurate possible input drive-to-radiance output mapping for each emitter pixel. This requires many highly-accurate radiance measurements of emitter output, as well as sophisticated manipulation of the resulting data set. AI-NUC expands the available radiance data set to include all measurements made of emitter output at any point. In addition, it allows the user to efficiently manage that data for use in the construction of a new NUC table that is generated from an improved fit of the emitter response curve. Not only does this improve the overall NUC by offering more statistics for interpolation than previous approaches, it also simplifies the removal of erroneous data from the set so that it does not propagate into the correction tables. AI-NUC is implemented by SBIR's IRWindows4 automated test software as part its advanced turnkey IRSP product (the Calibration Radiometry System or CRS), which incorporates all necessary measurement, calibration and NUC table generation capabilities. By employing AI-NUC on the CRS, SBIR has demonstrated the best uniformity results on resistive emitter arrays to date.

Low-cost real-time infrared scene generation for image projection and signal injection

NASA Astrophysics Data System (ADS)

Buford, James A., Jr.; King, David E.; Bowden, Mark H.

1998-07-01

As cost becomes an increasingly important factor in the development and testing of Infrared sensors and flight computer/processors, the need for accurate hardware-in-the- loop (HWIL) simulations is critical. In the past, expensive and complex dedicated scene generation hardware was needed to attain the fidelity necessary for accurate testing. Recent technological advances and innovative applications of established technologies are beginning to allow development of cost-effective replacements for dedicated scene generators. These new scene generators are mainly constructed from commercial-off-the-shelf (COTS) hardware and software components. At the U.S. Army Aviation and Missile Command (AMCOM) Missile Research, Development, and Engineering Center (MRDEC), researchers have developed such a dynamic IR scene generator (IRSG) built around COTS hardware and software. The IRSG is used to provide dynamic inputs to an IR scene projector for in-band seeker testing and for direct signal injection into the seeker or processor electronics. AMCOM MRDEC has developed a second generation IRSG, namely IRSG2, using the latest Silicon Graphics Incorporated (SGI) Onyx2 with Infinite Reality graphics. As reported in previous papers, the SGI Onyx Reality Engine 2 is the platform of the original IRSG that is now referred to as IRSG1. IRSG1 has been in operation and used daily for the past three years on several IR projection and signal injection HWIL programs. Using this second generation IRSG, frame rates have increased from 120 Hz to 400 Hz and intensity resolution from 12 bits to 16 bits. The key features of the IRSGs are real time missile frame rates and frame sizes, dynamic missile-to-target(s) viewpoint updated each frame in real-time by a six-degree-of- freedom (6DOF) system under test (SUT) simulation, multiple dynamic objects (e.g. targets, terrain/background, countermeasures, and atmospheric effects), latency compensation, point-to-extended source anti-aliased targets, and sensor modeling effects. This paper provides a comparison between the IRSG1 and IRSG2 systems and focuses on the IRSG software, real time features, and database development tools.

Anti-aliasing algorithm development

NASA Astrophysics Data System (ADS)

Bodrucki, F.; Davis, J.; Becker, J.; Cordell, J.

2017-10-01

In this paper, we discuss the testing image processing algorithms for mitigation of aliasing artifacts under pulsed illumination. Previously sensors were tested, one with a fixed frame rate and one with an adjustable frame rate, which results showed different degrees of operability when subjected to a Quantum Cascade Laser (QCL) laser pulsed at the frame rate of the fixe-rate sensor. We implemented algorithms to allow the adjustable frame-rate sensor to detect the presence of aliasing artifacts, and in response, to alter the frame rate of the sensor. The result was that the sensor output showed a varying laser intensity (beat note) as opposed to a fixed signal level. A MIRAGE Infrared Scene Projector (IRSP) was used to explore the efficiency of the new algorithms, introduction secondary elements into the sensor's field of view.

Preprocessing of region of interest localization based on local surface curvature analysis for three-dimensional reconstruction with multiresolution

NASA Astrophysics Data System (ADS)

Li, Wanjing; Schütze, Rainer; Böhler, Martin; Boochs, Frank; Marzani, Franck S.; Voisin, Yvon

2009-06-01

We present an approach to integrate a preprocessing step of the region of interest (ROI) localization into 3-D scanners (laser or stereoscopic). The definite objective is to make the 3-D scanner intelligent enough to localize rapidly in the scene, during the preprocessing phase, the regions with high surface curvature, so that precise scanning will be done only in these regions instead of in the whole scene. In this way, the scanning time can be largely reduced, and the results contain only pertinent data. To test its feasibility and efficiency, we simulated the preprocessing process under an active stereoscopic system composed of two cameras and a video projector. The ROI localization is done in an iterative way. First, the video projector projects a regular point pattern in the scene, and then the pattern is modified iteratively according to the local surface curvature of each reconstructed 3-D point. Finally, the last pattern is used to determine the ROI. Our experiments showed that with this approach, the system is capable to localize all types of objects, including small objects with small depth.

Obstacle Detection and Avoidance of a Mobile Robotic Platform Using Active Depth Sensing

DTIC Science & Technology

2014-06-01

price of nearly one tenth of a laser range finder, the Xbox Kinect uses an infrared projector and camera to capture images of its environment in three...inception. At the price of nearly one tenth of a laser range finder, the Xbox Kinect uses an infrared projector and camera to capture images of its...cropped between 280 and 480 pixels. ........11 Figure 9. RGB image captured by the camera on the Xbox Kinect. ...............................12 Figure

Study on general design of dual-DMD based infrared two-band scene simulation system

NASA Astrophysics Data System (ADS)

Pan, Yue; Qiao, Yang; Xu, Xi-ping

2017-02-01

Mid-wave infrared(MWIR) and long-wave infrared(LWIR) two-band scene simulation system is a kind of testing equipment that used for infrared two-band imaging seeker. Not only it would be qualified for working waveband, but also realize the essence requests that infrared radiation characteristics should correspond to the real scene. Past single-digital micromirror device (DMD) based infrared scene simulation system does not take the huge difference between targets and background radiation into account, and it cannot realize the separated modulation to two-band light beam. Consequently, single-DMD based infrared scene simulation system cannot accurately express the thermal scene model that upper-computer built, and it is not that practical. To solve the problem, we design a dual-DMD based, dual-channel, co-aperture, compact-structure infrared two-band scene simulation system. The operating principle of the system is introduced in detail, and energy transfer process of the hardware-in-the-loop simulation experiment is analyzed as well. Also, it builds the equation about the signal-to-noise ratio of infrared detector in the seeker, directing the system overall design. The general design scheme of system is given, including the creation of infrared scene model, overall control, optical-mechanical structure design and image registration. By analyzing and comparing the past designs, we discuss the arrangement of optical engine framework in the system. According to the main content of working principle and overall design, we summarize each key techniques in the system.

Research on the generation of the background with sea and sky in infrared scene

NASA Astrophysics Data System (ADS)

Dong, Yan-zhi; Han, Yan-li; Lou, Shu-li

2008-03-01

It is important for scene generation to keep the texture of infrared images in simulation of anti-ship infrared imaging guidance. We studied the fractal method and applied it to the infrared scene generation. We adopted the method of horizontal-vertical (HV) partition to encode the original image. Basing on the properties of infrared image with sea-sky background, we took advantage of Local Iteration Function System (LIFS) to decrease the complexity of computation and enhance the processing rate. Some results were listed. The results show that the fractal method can keep the texture of infrared image better and can be used in the infrared scene generation widely in future.

Optical system for object detection and delineation in space

NASA Astrophysics Data System (ADS)

Handelman, Amir; Shwartz, Shoam; Donitza, Liad; Chaplanov, Loran

2018-01-01

Object recognition and delineation is an important task in many environments, such as in crime scenes and operating rooms. Marking evidence or surgical tools and attracting the attention of the surrounding staff to the marked objects can affect people's lives. We present an optical system comprising a camera, computer, and small laser projector that can detect and delineate objects in the environment. To prove the optical system's concept, we show that it can operate in a hypothetical crime scene in which a pistol is present and automatically recognize and segment it by various computer-vision algorithms. Based on such segmentation, the laser projector illuminates the actual boundaries of the pistol and thus allows the persons in the scene to comfortably locate and measure the pistol without holding any intermediator device, such as an augmented reality handheld device, glasses, or screens. Using additional optical devices, such as diffraction grating and a cylinder lens, the pistol size can be estimated. The exact location of the pistol in space remains static, even after its removal. Our optical system can be fixed or dynamically moved, making it suitable for various applications that require marking of objects in space.

Combined use of a priori data for fast system self-calibration of a non-rigid multi-camera fringe projection system

NASA Astrophysics Data System (ADS)

Stavroulakis, Petros I.; Chen, Shuxiao; Sims-Waterhouse, Danny; Piano, Samanta; Southon, Nicholas; Bointon, Patrick; Leach, Richard

2017-06-01

In non-rigid fringe projection 3D measurement systems, where either the camera or projector setup can change significantly between measurements or the object needs to be tracked, self-calibration has to be carried out frequently to keep the measurements accurate1. In fringe projection systems, it is common to use methods developed initially for photogrammetry for the calibration of the camera(s) in the system in terms of extrinsic and intrinsic parameters. To calibrate the projector(s) an extra correspondence between a pre-calibrated camera and an image created by the projector is performed. These recalibration steps are usually time consuming and involve the measurement of calibrated patterns on planes, before the actual object can continue to be measured after a motion of a camera or projector has been introduced in the setup and hence do not facilitate fast 3D measurement of objects when frequent experimental setup changes are necessary. By employing and combining a priori information via inverse rendering, on-board sensors, deep learning and leveraging a graphics processor unit (GPU), we assess a fine camera pose estimation method which is based on optimising the rendering of a model of a scene and the object to match the view from the camera. We find that the success of this calibration pipeline can be greatly improved by using adequate a priori information from the aforementioned sources.

Generative technique for dynamic infrared image sequences

NASA Astrophysics Data System (ADS)

Zhang, Qian; Cao, Zhiguo; Zhang, Tianxu

2001-09-01

The generative technique of the dynamic infrared image was discussed in this paper. Because infrared sensor differs from CCD camera in imaging mechanism, it generates the infrared image by incepting the infrared radiation of scene (including target and background). The infrared imaging sensor is affected deeply by the atmospheric radiation, the environmental radiation and the attenuation of atmospheric radiation transfers. Therefore at first in this paper the imaging influence of all kinds of the radiations was analyzed and the calculation formula of radiation was provided, in addition, the passive scene and the active scene were analyzed separately. Then the methods of calculation in the passive scene were provided, and the functions of the scene model, the atmospheric transmission model and the material physical attribute databases were explained. Secondly based on the infrared imaging model, the design idea, the achievable way and the software frame for the simulation software of the infrared image sequence were introduced in SGI workstation. Under the guidance of the idea above, in the third segment of the paper an example of simulative infrared image sequences was presented, which used the sea and sky as background and used the warship as target and used the aircraft as eye point. At last the simulation synthetically was evaluated and the betterment scheme was presented.

Real-time generation of infrared ocean scene based on GPU

NASA Astrophysics Data System (ADS)

Jiang, Zhaoyi; Wang, Xun; Lin, Yun; Jin, Jianqiu

2007-12-01

Infrared (IR) image synthesis for ocean scene has become more and more important nowadays, especially for remote sensing and military application. Although a number of works present ready-to-use simulations, those techniques cover only a few possible ways of water interacting with the environment. And the detail calculation of ocean temperature is rarely considered by previous investigators. With the advance of programmable features of graphic card, many algorithms previously limited to offline processing have become feasible for real-time usage. In this paper, we propose an efficient algorithm for real-time rendering of infrared ocean scene using the newest features of programmable graphics processors (GPU). It differs from previous works in three aspects: adaptive GPU-based ocean surface tessellation, sophisticated balance equation of thermal balance for ocean surface, and GPU-based rendering for infrared ocean scene. Finally some results of infrared image are shown, which are in good accordance with real images.

Omnidirectional-view three-dimensional display system based on cylindrical selective-diffusing screen.

PubMed

Xia, Xinxing; Zheng, Zhenrong; Liu, Xu; Li, Haifeng; Yan, Caijie

2010-09-10

We utilized a high-frame-rate projector, a rotating mirror, and a cylindrical selective-diffusing screen to present a novel three-dimensional (3D) omnidirectional-view display system without the need for any special viewing aids. The display principle and image size are analyzed, and the common display zone is proposed. The viewing zone for one observation place is also studied. The experimental results verify this method, and a vivid color 3D scene with occlusion and smooth parallax is also demonstrated with the system.

Graphics processing unit (GPU) real-time infrared scene generation

NASA Astrophysics Data System (ADS)

Christie, Chad L.; Gouthas, Efthimios (Themie); Williams, Owen M.

2007-04-01

VIRSuite, the GPU-based suite of software tools developed at DSTO for real-time infrared scene generation, is described. The tools include the painting of scene objects with radiometrically-associated colours, translucent object generation, polar plot validation and versatile scene generation. Special features include radiometric scaling within the GPU and the presence of zoom anti-aliasing at the core of VIRSuite. Extension of the zoom anti-aliasing construct to cover target embedding and the treatment of translucent objects is described.

A 360-degree floating 3D display based on light field regeneration.

PubMed

Xia, Xinxing; Liu, Xu; Li, Haifeng; Zheng, Zhenrong; Wang, Han; Peng, Yifan; Shen, Weidong

2013-05-06

Using light field reconstruction technique, we can display a floating 3D scene in the air, which is 360-degree surrounding viewable with correct occlusion effect. A high-frame-rate color projector and flat light field scanning screen are used in the system to create the light field of real 3D scene in the air above the spinning screen. The principle and display performance of this approach are investigated in this paper. The image synthesis method for all the surrounding viewpoints is analyzed, and the 3D spatial resolution and angular resolution of the common display zone are employed to evaluate display performance. The prototype is achieved and the real 3D color animation image has been presented vividly. The experimental results verified the representability of this method.

NMR and NQR parameters of ethanol crystal

NASA Astrophysics Data System (ADS)

Milinković, M.; Bilalbegović, G.

2012-04-01

Electric field gradients and chemical shielding tensors of the stable monoclinic crystal phase of ethanol are computed. The projector-augmented wave (PAW) and gauge-including projector-augmented wave (GIPAW) models in the periodic plane-wave density functional theory are used. The crystal data from X-ray measurements, as well as the structures where either all atomic, or only hydrogen atom positions are optimized in the density functional theory are analyzed. These structural models are also studied by including the semi-empirical van der Waals correction to the density functional theory. Infrared spectra of these five crystal models are calculated.

Robust infrared targets tracking with covariance matrix representation

NASA Astrophysics Data System (ADS)

Cheng, Jian

2009-07-01

Robust infrared target tracking is an important and challenging research topic in many military and security applications, such as infrared imaging guidance, infrared reconnaissance, scene surveillance, etc. To effectively tackle the nonlinear and non-Gaussian state estimation problems, particle filtering is introduced to construct the theory framework of infrared target tracking. Under this framework, the observation probabilistic model is one of main factors for infrared targets tracking performance. In order to improve the tracking performance, covariance matrices are introduced to represent infrared targets with the multi-features. The observation probabilistic model can be constructed by computing the distance between the reference target's and the target samples' covariance matrix. Because the covariance matrix provides a natural tool for integrating multiple features, and is scale and illumination independent, target representation with covariance matrices can hold strong discriminating ability and robustness. Two experimental results demonstrate the proposed method is effective and robust for different infrared target tracking, such as the sensor ego-motion scene, and the sea-clutter scene.

IR characteristic simulation of city scenes based on radiosity model

NASA Astrophysics Data System (ADS)

Xiong, Xixian; Zhou, Fugen; Bai, Xiangzhi; Yu, Xiyu

2013-09-01

Reliable modeling for thermal infrared (IR) signatures of real-world city scenes is required for signature management of civil and military platforms. Traditional modeling methods generally assume that scene objects are individual entities during the physical processes occurring in infrared range. However, in reality, the physical scene involves convective and conductive interactions between objects as well as the radiations interactions between objects. A method based on radiosity model describes these complex effects. It has been developed to enable an accurate simulation for the radiance distribution of the city scenes. Firstly, the physical processes affecting the IR characteristic of city scenes were described. Secondly, heat balance equations were formed on the basis of combining the atmospheric conditions, shadow maps and the geometry of scene. Finally, finite difference method was used to calculate the kinetic temperature of object surface. A radiosity model was introduced to describe the scattering effect of radiation between surface elements in the scene. By the synthesis of objects radiance distribution in infrared range, we could obtain the IR characteristic of scene. Real infrared images and model predictions were shown and compared. The results demonstrate that this method can realistically simulate the IR characteristic of city scenes. It effectively displays the infrared shadow effects and the radiation interactions between objects in city scenes.

Work step indication with grid-pattern projection for demented senior people.

PubMed

Uranishi, Yuki; Yamamoto, Goshiro; Asghar, Zeeshan; Pulli, Petri; Kato, Hirokazu; Oshiro, Osamu

2013-01-01

This paper proposes a work step indication method for supporting daily work with a grid-pattern projection. To support an independent life of demented senior people, it is desirable that an instruction is easy to understand visually and not complicated. The proposed method in this paper uses a range image sensor and a camera in addition to a projector. A 3D geometry of a target scene is measured by the range image sensor, and the grid-pattern is projected onto the scene directly. Direct projection of the work step is easier to be associated with the target objects around the assisted person, and the grid-pattern is a solution to indicate the spatial instruction. A prototype has been implemented and has demonstrated that the proposed grid-pattern projection is easy to show the work step.

Enhanced LWIR NUC using an uncooled microbolometer camera

NASA Astrophysics Data System (ADS)

LaVeigne, Joe; Franks, Greg; Sparkman, Kevin; Prewarski, Marcus; Nehring, Brian

2011-06-01

Performing a good non-uniformity correction is a key part of achieving optimal performance from an infrared scene projector, and the best NUC is performed in the band of interest for the sensor being tested. While cooled, large format MWIR cameras are readily available and have been successfully used to perform NUC, similar cooled, large format LWIR cameras are not as common and are prohibitively expensive. Large format uncooled cameras are far more available and affordable, but present a range of challenges in practical use for performing NUC on an IRSP. Some of these challenges were discussed in a previous paper. In this discussion, we report results from a continuing development program to use a microbolometer camera to perform LWIR NUC on an IRSP. Camera instability and temporal response and thermal resolution were the main problems, and have been solved by the implementation of several compensation strategies as well as hardware used to stabilize the camera. In addition, other processes have been developed to allow iterative improvement as well as supporting changes of the post-NUC lookup table without requiring re-collection of the pre-NUC data with the new LUT in use.

Scene-based nonuniformity correction technique for infrared focal-plane arrays.

PubMed

Liu, Yong-Jin; Zhu, Hong; Zhao, Yi-Gong

2009-04-20

A scene-based nonuniformity correction algorithm is presented to compensate for the gain and bias nonuniformity in infrared focal-plane array sensors, which can be separated into three parts. First, an interframe-prediction method is used to estimate the true scene, since nonuniformity correction is a typical blind-estimation problem and both scene values and detector parameters are unavailable. Second, the estimated scene, along with its corresponding observed data obtained by detectors, is employed to update the gain and the bias by means of a line-fitting technique. Finally, with these nonuniformity parameters, the compensated output of each detector is obtained by computing a very simple formula. The advantages of the proposed algorithm lie in its low computational complexity and storage requirements and ability to capture temporal drifts in the nonuniformity parameters. The performance of every module is demonstrated with simulated and real infrared image sequences. Experimental results indicate that the proposed algorithm exhibits a superior correction effect.

Controllable 3D Display System Based on Frontal Projection Lenticular Screen

NASA Astrophysics Data System (ADS)

Feng, Q.; Sang, X.; Yu, X.; Gao, X.; Wang, P.; Li, C.; Zhao, T.

2014-08-01

A novel auto-stereoscopic three-dimensional (3D) projection display system based on the frontal projection lenticular screen is demonstrated. It can provide high real 3D experiences and the freedom of interaction. In the demonstrated system, the content can be changed and the dense of viewing points can be freely adjusted according to the viewers' demand. The high dense viewing points can provide smooth motion parallax and larger image depth without blurry. The basic principle of stereoscopic display is described firstly. Then, design architectures including hardware and software are demonstrated. The system consists of a frontal projection lenticular screen, an optimally designed projector-array and a set of multi-channel image processors. The parameters of the frontal projection lenticular screen are based on the demand of viewing such as the viewing distance and the width of view zones. Each projector is arranged on an adjustable platform. The set of multi-channel image processors are made up of six PCs. One of them is used as the main controller, the other five client PCs can process 30 channel signals and transmit them to the projector-array. Then a natural 3D scene will be perceived based on the frontal projection lenticular screen with more than 1.5 m image depth in real time. The control section is presented in detail, including parallax adjustment, system synchronization, distortion correction, etc. Experimental results demonstrate the effectiveness of this novel controllable 3D display system.

Physics Based Modeling and Rendering of Vegetation in the Thermal Infrared

NASA Technical Reports Server (NTRS)

Smith, J. A.; Ballard, J. R., Jr.

1999-01-01

We outline a procedure for rendering physically-based thermal infrared images of simple vegetation scenes. Our approach incorporates the biophysical processes that affect the temperature distribution of the elements within a scene. Computer graphics plays a key role in two respects. First, in computing the distribution of scene shaded and sunlit facets and, second, in the final image rendering once the temperatures of all the elements in the scene have been computed. We illustrate our approach for a simple corn scene where the three-dimensional geometry is constructed based on measured morphological attributes of the row crop. Statistical methods are used to construct a representation of the scene in agreement with the measured characteristics. Our results are quite good. The rendered images exhibit realistic behavior in directional properties as a function of view and sun angle. The root-mean-square error in measured versus predicted brightness temperatures for the scene was 2.1 deg C.

Electrostatic artificial eyelid actuator as an analog micromirror device

NASA Astrophysics Data System (ADS)

Goodwin, Scott H.; Dausch, David E.; Solomon, Steven L.; Lamvik, Michael K.

2005-05-01

An electrostatic MEMS actuator is described for use as an analog micromirror device (AMD) for high performance, broadband, hardware-in-the-loop (HWIL) scene generation. Current state-of-the-art technology is based on resistively heated pixel arrays. As these arrays drive to the higher scene temperatures required by missile defense scenarios, the power required to drive the large format resistive arrays will ultimately become prohibitive. Existing digital micromirrors (DMD) are, in principle, capable of generating the required scene irradiances, but suffer from limited dynamic range, resolution and flicker effects. An AMD would be free of these limitations, and so represents a viable alternative for high performance UV/VIS/IR scene generation. An electrostatic flexible film actuator technology, developed for use as "artificial eyelid" shutters for focal plane sensors to protect against damaging radiation, is suitable as an AMD for analog control of projection irradiance. In shutter applications, the artificial eyelid actuator contained radius of curvature as low as 25um and operated at high voltage (>200V). Recent testing suggests that these devices are capable of analog operation as reflective microcantilever mirrors appropriate for scene projector systems. In this case, the device would possess larger radius and operate at lower voltages (20-50V). Additionally, frame rates have been measured at greater than 5kHz for continuous operation. The paper will describe the artificial eyelid technology, preliminary measurements of analog test pixels, and design aspects related to application for scene projection systems. We believe this technology will enable AMD projectors with at least 5122 spatial resolution, non-temporally-modulated output, and pixel response times of <1.25ms.

A Method of Sky Ripple Residual Nonuniformity Reduction for a Cooled Infrared Imager and Hardware Implementation.

PubMed

Li, Yiyang; Jin, Weiqi; Li, Shuo; Zhang, Xu; Zhu, Jin

2017-05-08

Cooled infrared detector arrays always suffer from undesired ripple residual nonuniformity (RNU) in sky scene observations. The ripple residual nonuniformity seriously affects the imaging quality, especially for small target detection. It is difficult to eliminate it using the calibration-based techniques and the current scene-based nonuniformity algorithms. In this paper, we present a modified temporal high-pass nonuniformity correction algorithm using fuzzy scene classification. The fuzzy scene classification is designed to control the correction threshold so that the algorithm can remove ripple RNU without degrading the scene details. We test the algorithm on a real infrared sequence by comparing it to several well-established methods. The result shows that the algorithm has obvious advantages compared with the tested methods in terms of detail conservation and convergence speed for ripple RNU correction. Furthermore, we display our architecture with a prototype built on a Xilinx Virtex-5 XC5VLX50T field-programmable gate array (FPGA), which has two advantages: (1) low resources consumption; and (2) small hardware delay (less than 10 image rows). It has been successfully applied in an actual system.

A Method of Sky Ripple Residual Nonuniformity Reduction for a Cooled Infrared Imager and Hardware Implementation

PubMed Central

Li, Yiyang; Jin, Weiqi; Li, Shuo; Zhang, Xu; Zhu, Jin

2017-01-01

Cooled infrared detector arrays always suffer from undesired ripple residual nonuniformity (RNU) in sky scene observations. The ripple residual nonuniformity seriously affects the imaging quality, especially for small target detection. It is difficult to eliminate it using the calibration-based techniques and the current scene-based nonuniformity algorithms. In this paper, we present a modified temporal high-pass nonuniformity correction algorithm using fuzzy scene classification. The fuzzy scene classification is designed to control the correction threshold so that the algorithm can remove ripple RNU without degrading the scene details. We test the algorithm on a real infrared sequence by comparing it to several well-established methods. The result shows that the algorithm has obvious advantages compared with the tested methods in terms of detail conservation and convergence speed for ripple RNU correction. Furthermore, we display our architecture with a prototype built on a Xilinx Virtex-5 XC5VLX50T field-programmable gate array (FPGA), which has two advantages: (1) low resources consumption; and (2) small hardware delay (less than 10 image rows). It has been successfully applied in an actual system. PMID:28481320

Utilization of DIRSIG in support of real-time infrared scene generation

NASA Astrophysics Data System (ADS)

Sanders, Jeffrey S.; Brown, Scott D.

2000-07-01

Real-time infrared scene generation for hardware-in-the-loop has been a traditionally difficult challenge. Infrared scenes are usually generated using commercial hardware that was not designed to properly handle the thermal and environmental physics involved. Real-time infrared scenes typically lack details that are included in scenes rendered in no-real- time by ray-tracing programs such as the Digital Imaging and Remote Sensing Scene Generation (DIRSIG) program. However, executing DIRSIG in real-time while retaining all the physics is beyond current computational capabilities for many applications. DIRSIG is a first principles-based synthetic image generation model that produces multi- or hyper-spectral images in the 0.3 to 20 micron region of the electromagnetic spectrum. The DIRSIG model is an integrated collection of independent first principles based on sub-models, each of which works in conjunction to produce radiance field images with high radiometric fidelity. DIRSIG uses the MODTRAN radiation propagation model for exo-atmospheric irradiance, emitted and scattered radiances (upwelled and downwelled) and path transmission predictions. This radiometry submodel utilizes bidirectional reflectance data, accounts for specular and diffuse background contributions, and features path length dependent extinction and emission for transmissive bodies (plumes, clouds, etc.) which may be present in any target, background or solar path. This detailed environmental modeling greatly enhances the number of rendered features and hence, the fidelity of a rendered scene. While DIRSIG itself cannot currently be executed in real-time, its outputs can be used to provide scene inputs for real-time scene generators. These inputs can incorporate significant features such as target to background thermal interactions, static background object thermal shadowing, and partially transmissive countermeasures. All of these features represent significant improvements over the current state of the art in real-time IR scene generation.

Confocal retinal imaging using a digital light projector with a near infrared VCSEL source

NASA Astrophysics Data System (ADS)

Muller, Matthew S.; Elsner, Ann E.

2018-02-01

A custom near infrared VCSEL source has been implemented in a confocal non-mydriatic retinal camera, the Digital Light Ophthalmoscope (DLO). The use of near infrared light improves patient comfort, avoids pupil constriction, penetrates the deeper retina, and does not mask visual stimuli. The DLO performs confocal imaging by synchronizing a sequence of lines displayed with a digital micromirror device to the rolling shutter exposure of a 2D CMOS camera. Real-time software adjustments enable multiply scattered light imaging, which rapidly and cost-effectively emphasizes drusen and other scattering disruptions in the deeper retina. A separate 5.1" LCD display provides customizable visible stimuli for vision experiments with simultaneous near infrared imaging.

Coloured computational imaging with single-pixel detectors based on a 2D discrete cosine transform

NASA Astrophysics Data System (ADS)

Liu, Bao-Lei; Yang, Zhao-Hua; Liu, Xia; Wu, Ling-An

2017-02-01

We propose and demonstrate a computational imaging technique that uses structured illumination based on a two-dimensional discrete cosine transform to perform imaging with a single-pixel detector. A scene is illuminated by a projector with two sets of orthogonal patterns, then by applying an inverse cosine transform to the spectra obtained from the single-pixel detector a full-colour image is retrieved. This technique can retrieve an image from sub-Nyquist measurements, and the background noise is easily cancelled to give excellent image quality. Moreover, the experimental set-up is very simple.

Signature modelling and radiometric rendering equations in infrared scene simulation systems

NASA Astrophysics Data System (ADS)

Willers, Cornelius J.; Willers, Maria S.; Lapierre, Fabian

2011-11-01

The development and optimisation of modern infrared systems necessitates the use of simulation systems to create radiometrically realistic representations (e.g. images) of infrared scenes. Such simulation systems are used in signature prediction, the development of surveillance and missile sensors, signal/image processing algorithm development and aircraft self-protection countermeasure system development and evaluation. Even the most cursory investigation reveals a multitude of factors affecting the infrared signatures of realworld objects. Factors such as spectral emissivity, spatial/volumetric radiance distribution, specular reflection, reflected direct sunlight, reflected ambient light, atmospheric degradation and more, all affect the presentation of an object's instantaneous signature. The signature is furthermore dynamically varying as a result of internal and external influences on the object, resulting from the heat balance comprising insolation, internal heat sources, aerodynamic heating (airborne objects), conduction, convection and radiation. In order to accurately render the object's signature in a computer simulation, the rendering equations must therefore account for all the elements of the signature. In this overview paper, the signature models, rendering equations and application frameworks of three infrared simulation systems are reviewed and compared. The paper first considers the problem of infrared scene simulation in a framework for simulation validation. This approach provides concise definitions and a convenient context for considering signature models and subsequent computer implementation. The primary radiometric requirements for an infrared scene simulator are presented next. The signature models and rendering equations implemented in OSMOSIS (Belgian Royal Military Academy), DIRSIG (Rochester Institute of Technology) and OSSIM (CSIR & Denel Dynamics) are reviewed. In spite of these three simulation systems' different application focus areas, their underlying physics-based approach is similar. The commonalities and differences between the different systems are investigated, in the context of their somewhat different application areas. The application of an infrared scene simulation system towards the development of imaging missiles and missile countermeasures are briefly described. Flowing from the review of the available models and equations, recommendations are made to further enhance and improve the signature models and rendering equations in infrared scene simulators.

Confocal Retinal Imaging Using a Digital Light Projector with a Near Infrared VCSEL Source

PubMed Central

Muller, Matthew S.; Elsner, Ann E.

2018-01-01

A custom near infrared VCSEL source has been implemented in a confocal non-mydriatic retinal camera, the Digital Light Ophthalmoscope (DLO). The use of near infrared light improves patient comfort, avoids pupil constriction, penetrates the deeper retina, and does not mask visual stimuli. The DLO performs confocal imaging by synchronizing a sequence of lines displayed with a digital micromirror device to the rolling shutter exposure of a 2D CMOS camera. Real-time software adjustments enable multiply scattered light imaging, which rapidly and cost-effectively emphasizes drusen and other scattering disruptions in the deeper retina. A separate 5.1″ LCD display provides customizable visible stimuli for vision experiments with simultaneous near infrared imaging. PMID:29899586

Sea-Based Infrared Scene Interpretation by Background Type Classification and Coastal Region Detection for Small Target Detection

PubMed Central

Kim, Sungho

2015-01-01

Sea-based infrared search and track (IRST) is important for homeland security by detecting missiles and asymmetric boats. This paper proposes a novel scheme to interpret various infrared scenes by classifying the infrared background types and detecting the coastal regions in omni-directional images. The background type or region-selective small infrared target detector should be deployed to maximize the detection rate and to minimize the number of false alarms. A spatial filter-based small target detector is suitable for identifying stationary incoming targets in remote sea areas with sky only. Many false detections can occur if there is an image sector containing a coastal region, due to ground clutter and the difficulty in finding true targets using the same spatial filter-based detector. A temporal filter-based detector was used to handle these problems. Therefore, the scene type and coastal region information is critical to the success of IRST in real-world applications. In this paper, the infrared scene type was determined using the relationships between the sensor line-of-sight (LOS) and a horizontal line in an image. The proposed coastal region detector can be activated if the background type of the probing sector is determined to be a coastal region. Coastal regions can be detected by fusing the region map and curve map. The experimental results on real infrared images highlight the feasibility of the proposed sea-based scene interpretation. In addition, the effects of the proposed scheme were analyzed further by applying region-adaptive small target detection. PMID:26404308

Infrared imaging of the crime scene: possibilities and pitfalls.

PubMed

Edelman, Gerda J; Hoveling, Richelle J M; Roos, Martin; van Leeuwen, Ton G; Aalders, Maurice C G

2013-09-01

All objects radiate infrared energy invisible to the human eye, which can be imaged by infrared cameras, visualizing differences in temperature and/or emissivity of objects. Infrared imaging is an emerging technique for forensic investigators. The rapid, nondestructive, and noncontact features of infrared imaging indicate its suitability for many forensic applications, ranging from the estimation of time of death to the detection of blood stains on dark backgrounds. This paper provides an overview of the principles and instrumentation involved in infrared imaging. Difficulties concerning the image interpretation due to different radiation sources and different emissivity values within a scene are addressed. Finally, reported forensic applications are reviewed and supported by practical illustrations. When introduced in forensic casework, infrared imaging can help investigators to detect, to visualize, and to identify useful evidence nondestructively. © 2013 American Academy of Forensic Sciences.

A Multi-Wavelength Thermal Infrared and Reflectance Scene Simulation Model

NASA Technical Reports Server (NTRS)

Ballard, J. R., Jr.; Smith, J. A.; Smith, David E. (Technical Monitor)

2002-01-01

Several theoretical calculations are presented and our approach discussed for simulating overall composite scene thermal infrared exitance and canopy bidirectional reflectance of a forest canopy. Calculations are performed for selected wavelength bands of the DOE Multispectral Thermal Imagery and comparisons with atmospherically corrected MTI imagery are underway. NASA EO-1 Hyperion observations also are available and the favorable comparison of our reflective model results with these data are reported elsewhere.

Scene-based nonuniformity correction algorithm based on interframe registration.

PubMed

Zuo, Chao; Chen, Qian; Gu, Guohua; Sui, Xiubao

2011-06-01

In this paper, we present a simple and effective scene-based nonuniformity correction (NUC) method for infrared focal plane arrays based on interframe registration. This method estimates the global translation between two adjacent frames and minimizes the mean square error between the two properly registered images to make any two detectors with the same scene produce the same output value. In this way, the accumulation of the registration error can be avoided and the NUC can be achieved. The advantages of the proposed algorithm lie in its low computational complexity and storage requirements and ability to capture temporal drifts in the nonuniformity parameters. The performance of the proposed technique is thoroughly studied with infrared image sequences with simulated nonuniformity and infrared imagery with real nonuniformity. It shows a significantly fast and reliable fixed-pattern noise reduction and obtains an effective frame-by-frame adaptive estimation of each detector's gain and offset.

Augmented reality 3D display using head-mounted projectors and transparent retro-reflective screen

NASA Astrophysics Data System (ADS)

Soomro, Shoaib R.; Urey, Hakan

2017-02-01

A 3D augmented reality display is proposed that can provide glass-free stereo parallax using a highly transparent projection screen. The proposed display is based on a transparent retro-reflective screen and a pair of laser pico projectors placed close to the viewer's head. The retro-reflective screen directs incident light towards its source with little scattering so that each of the viewer's eyes only perceives the content projected by the associated projector. Each projector displays one of the two components (left or right channel) of stereo content. The retro-reflective nature of screen provides high brightness compared to the regular diffused screens. The partially patterned retro-reflective material on clear substrate introduces optical transparency and facilitates the viewer to see the real-world scene on the other side of screen. The working principle and design of the proposed see-through 3D display are presented. A tabletop prototype consisting of an in-house fabricated 60×40cm2 see-through retro-reflective screen and a pair of 30 lumen pico-projectors with custom 3D printed housings is demonstrated. Geometric calibration between projectors and optimal viewing conditions (eye box size, eye-to-projector distance) are discussed. The display performance is evaluated by measuring the brightness and crosstalk for each eye. The screen provides high brightness (up to 300 cd/m2 per eye) using 30 lumens mobile projectors while maintaining the 75% screen transparency. The crosstalk between left and right views is measured as <10% at the optimum distance of 125-175 cm, which is within acceptable range.

A projector calibration method for monocular structured light system based on digital image correlation

NASA Astrophysics Data System (ADS)

Feng, Zhixin

2018-02-01

Projector calibration is crucial for a camera-projector three-dimensional (3-D) structured light measurement system, which has one camera and one projector. In this paper, a novel projector calibration method is proposed based on digital image correlation. In the method, the projector is viewed as an inverse camera, and a plane calibration board with feature points is used to calibrate the projector. During the calibration processing, a random speckle pattern is projected onto the calibration board with different orientations to establish the correspondences between projector images and camera images. Thereby, dataset for projector calibration are generated. Then the projector can be calibrated using a well-established camera calibration algorithm. The experiment results confirm that the proposed method is accurate and reliable for projector calibration.

An improved contrast enhancement algorithm for infrared images based on adaptive double plateaus histogram equalization

NASA Astrophysics Data System (ADS)

Li, Shuo; Jin, Weiqi; Li, Li; Li, Yiyang

2018-05-01

Infrared thermal images can reflect the thermal-radiation distribution of a particular scene. However, the contrast of the infrared images is usually low. Hence, it is generally necessary to enhance the contrast of infrared images in advance to facilitate subsequent recognition and analysis. Based on the adaptive double plateaus histogram equalization, this paper presents an improved contrast enhancement algorithm for infrared thermal images. In the proposed algorithm, the normalized coefficient of variation of the histogram, which characterizes the level of contrast enhancement, is introduced as feedback information to adjust the upper and lower plateau thresholds. The experiments on actual infrared images show that compared to the three typical contrast-enhancement algorithms, the proposed algorithm has better scene adaptability and yields better contrast-enhancement results for infrared images with more dark areas or a higher dynamic range. Hence, it has high application value in contrast enhancement, dynamic range compression, and digital detail enhancement for infrared thermal images.

Polarization measurements made on LFRA and OASIS emitter arrays

NASA Astrophysics Data System (ADS)

Geske, Jon; Sparkman, Kevin; Oleson, Jim; Laveigne, Joe; Sieglinger, Breck; Marlow, Steve; Lowry, Heard; Burns, James

2008-04-01

Polarization is increasingly being considered as a method of discrimination in passive sensing applications. In this paper the degree of polarization of the thermal emission from the emitter arrays of two new Santa Barbara Infrared (SBIR) micro-bolometer resistor array scene projectors was characterized at ambient temperature and at 77 K. The emitter arrays characterized were from the Large Format Resistive Array (LFRA) and the Optimized Arrays for Space-Background Infrared Simulation (OASIS) scene projectors. This paper reports the results of this testing.

A read-in IC for infrared scene projectors with voltage drop compensation for improved uniformity of emitter current

NASA Astrophysics Data System (ADS)

Cho, Min Ji; Shin, Uisub; Lee, Hee Chul

2017-05-01

This paper proposes a read-in integrated circuit (RIIC) for infrared scene projectors, which compensates for the voltage drops in ground lines in order to improve the uniformity of the emitter current. A current output digital-to-analog converter is utilized to convert digital scene data into scene data currents. The unit cells in the array receive the scene data current and convert it into data voltage, which simultaneously self-adjusts to account for the voltage drop in the ground line in order to generate the desired emitter current independently of variations in the ground voltage. A 32 × 32 RIIC unit cell array was designed and fabricated using a 0.18-μm CMOS process. The experimental results demonstrate that the proposed RIIC can output a maximum emitter current of 150 μA and compensate for a voltage drop in the ground line of up to 500 mV under a 3.3-V supply. The uniformity of the emitter current is significantly improved compared to that of a conventional RIIC.

Improved neural network based scene-adaptive nonuniformity correction method for infrared focal plane arrays.

PubMed

Lai, Rui; Yang, Yin-tang; Zhou, Duan; Li, Yue-jin

2008-08-20

An improved scene-adaptive nonuniformity correction (NUC) algorithm for infrared focal plane arrays (IRFPAs) is proposed. This method simultaneously estimates the infrared detectors' parameters and eliminates the nonuniformity causing fixed pattern noise (FPN) by using a neural network (NN) approach. In the learning process of neuron parameter estimation, the traditional LMS algorithm is substituted with the newly presented variable step size (VSS) normalized least-mean square (NLMS) based adaptive filtering algorithm, which yields faster convergence, smaller misadjustment, and lower computational cost. In addition, a new NN structure is designed to estimate the desired target value, which promotes the calibration precision considerably. The proposed NUC method reaches high correction performance, which is validated by the experimental results quantitatively tested with a simulative testing sequence and a real infrared image sequence.

Irdis: A Digital Scene Storage And Processing System For Hardware-In-The-Loop Missile Testing

NASA Astrophysics Data System (ADS)

Sedlar, Michael F.; Griffith, Jerry A.

1988-07-01

This paper describes the implementation of a Seeker Evaluation and Test Simulation (SETS) Facility at Eglin Air Force Base. This facility will be used to evaluate imaging infrared (IIR) guided weapon systems by performing various types of laboratory tests. One such test is termed Hardware-in-the-Loop (HIL) simulation (Figure 1) in which the actual flight of a weapon system is simulated as closely as possible in the laboratory. As shown in the figure, there are four major elements in the HIL test environment; the weapon/sensor combination, an aerodynamic simulator, an imagery controller, and an infrared imagery system. The paper concentrates on the approaches and methodologies used in the imagery controller and infrared imaging system elements for generating scene information. For procurement purposes, these two elements have been combined into an Infrared Digital Injection System (IRDIS) which provides scene storage, processing, and output interface to drive a radiometric display device or to directly inject digital video into the weapon system (bypassing the sensor). The paper describes in detail how standard and custom image processing functions have been combined with off-the-shelf mass storage and computing devices to produce a system which provides high sample rates (greater than 90 Hz), a large terrain database, high weapon rates of change, and multiple independent targets. A photo based approach has been used to maximize terrain and target fidelity, thus providing a rich and complex scene for weapon/tracker evaluation.

Comparative Evaluation of Background Subtraction Algorithms in Remote Scene Videos Captured by MWIR Sensors

PubMed Central

Yao, Guangle; Lei, Tao; Zhong, Jiandan; Jiang, Ping; Jia, Wenwu

2017-01-01

Background subtraction (BS) is one of the most commonly encountered tasks in video analysis and tracking systems. It distinguishes the foreground (moving objects) from the video sequences captured by static imaging sensors. Background subtraction in remote scene infrared (IR) video is important and common to lots of fields. This paper provides a Remote Scene IR Dataset captured by our designed medium-wave infrared (MWIR) sensor. Each video sequence in this dataset is identified with specific BS challenges and the pixel-wise ground truth of foreground (FG) for each frame is also provided. A series of experiments were conducted to evaluate BS algorithms on this proposed dataset. The overall performance of BS algorithms and the processor/memory requirements were compared. Proper evaluation metrics or criteria were employed to evaluate the capability of each BS algorithm to handle different kinds of BS challenges represented in this dataset. The results and conclusions in this paper provide valid references to develop new BS algorithm for remote scene IR video sequence, and some of them are not only limited to remote scene or IR video sequence but also generic for background subtraction. The Remote Scene IR dataset and the foreground masks detected by each evaluated BS algorithm are available online: https://github.com/JerryYaoGl/BSEvaluationRemoteSceneIR. PMID:28837112

2D virtual texture on 3D real object with coded structured light

NASA Astrophysics Data System (ADS)

Molinier, Thierry; Fofi, David; Salvi, Joaquim; Gorria, Patrick

2008-02-01

Augmented reality is used to improve color segmentation on human body or on precious no touch artifacts. We propose a technique to project a synthesized texture on real object without contact. Our technique can be used in medical or archaeological application. By projecting a suitable set of light patterns onto the surface of a 3D real object and by capturing images with a camera, a large number of correspondences can be found and the 3D points can be reconstructed. We aim to determine these points of correspondence between cameras and projector from a scene without explicit points and normals. We then project an adjusted texture onto the real object surface. We propose a global and automatic method to virtually texture a 3D real object.

A projective surgical navigation system for cancer resection

NASA Astrophysics Data System (ADS)

Gan, Qi; Shao, Pengfei; Wang, Dong; Ye, Jian; Zhang, Zeshu; Wang, Xinrui; Xu, Ronald

2016-03-01

Near infrared (NIR) fluorescence imaging technique can provide precise and real-time information about tumor location during a cancer resection surgery. However, many intraoperative fluorescence imaging systems are based on wearable devices or stand-alone displays, leading to distraction of the surgeons and suboptimal outcome. To overcome these limitations, we design a projective fluorescence imaging system for surgical navigation. The system consists of a LED excitation light source, a monochromatic CCD camera, a host computer, a mini projector and a CMOS camera. A software program is written by C++ to call OpenCV functions for calibrating and correcting fluorescence images captured by the CCD camera upon excitation illumination of the LED source. The images are projected back to the surgical field by the mini projector. Imaging performance of this projective navigation system is characterized in a tumor simulating phantom. Image-guided surgical resection is demonstrated in an ex-vivo chicken tissue model. In all the experiments, the projected images by the projector match well with the locations of fluorescence emission. Our experimental results indicate that the proposed projective navigation system can be a powerful tool for pre-operative surgical planning, intraoperative surgical guidance, and postoperative assessment of surgical outcome. We have integrated the optoelectronic elements into a compact and miniaturized system in preparation for further clinical validation.

A two-dimensional location method based on digital micromirror device used in interactive projection systems

NASA Astrophysics Data System (ADS)

Chen, Liangjun; Ni, Kai; Zhou, Qian; Cheng, Xuemin; Ma, Jianshe; Gao, Yuan; Sun, Peng; Li, Yi; Liu, Minxia

2010-11-01

Interactive projection systems based on CCD/CMOS have been greatly developed in recent years. They can locate and trace the movement of a pen equipped with an infrared LED, and displays the user's handwriting or react to the user's operation in real time. However, a major shortcoming is that the location device and the projector are independent with each other, including both the optical system and the control system. This requires construction of two optical systems, calibration of the differences between the projector view and the camera view, and also synchronization between two control systems, etc. In this paper, we introduced a two-dimensional location method based on digital micro-mirror device (DMD). The DMD is used as the display device and the position detector in turn. By serially flipping the micro-mirrors on the DMD according to a specially designed scheme and monitoring the reflected light energy, the image spot of the infrared LED can be quickly located. By using this method, the same optical system as well as the DMD can be multiplexed for projection and location, which will reduce the complexity and cost of the whole system. Furthermore, this method can also achieve high positioning accuracy and sampling rates. The results of location experiments are given.

Advanced Wavefront Sensing and Control Testbed (AWCT)

NASA Technical Reports Server (NTRS)

Shi, Fang; Basinger, Scott A.; Diaz, Rosemary T.; Gappinger, Robert O.; Tang, Hong; Lam, Raymond K.; Sidick, Erkin; Hein, Randall C.; Rud, Mayer; Troy, Mitchell

2010-01-01

The Advanced Wavefront Sensing and Control Testbed (AWCT) is built as a versatile facility for developing and demonstrating, in hardware, the future technologies of wave front sensing and control algorithms for active optical systems. The testbed includes a source projector for a broadband point-source and a suite of extended scene targets, a dispersed fringe sensor, a Shack-Hartmann camera, and an imaging camera capable of phase retrieval wavefront sensing. The testbed also provides two easily accessible conjugated pupil planes which can accommodate the active optical devices such as fast steering mirror, deformable mirror, and segmented mirrors. In this paper, we describe the testbed optical design, testbed configurations and capabilities, as well as the initial results from the testbed hardware integrations and tests.

Enhancement of multispectral thermal infrared images - Decorrelation contrast stretching

NASA Technical Reports Server (NTRS)

Gillespie, Alan R.

1992-01-01

Decorrelation contrast stretching is an effective method for displaying information from multispectral thermal infrared (TIR) images. The technique involves transformation of the data to principle components ('decorrelation'), independent contrast 'stretching' of data from the new 'decorrelated' image bands, and retransformation of the stretched data back to the approximate original axes, based on the inverse of the principle component rotation. The enhancement is robust in that colors of the same scene components are similar in enhanced images of similar scenes, or the same scene imaged at different times. Decorrelation contrast stretching is reviewed in the context of other enhancements applied to TIR images.

Synthesis multi-projector content for multi-projector three dimension display using a layered representation

NASA Astrophysics Data System (ADS)

Qin, Chen; Ren, Bin; Guo, Longfei; Dou, Wenhua

2014-11-01

Multi-projector three dimension display is a promising multi-view glass-free three dimension (3D) display technology, can produce full colour high definition 3D images on its screen. One key problem of multi-projector 3D display is how to acquire the source images of projector array while avoiding pseudoscopic problem. This paper analysis the displaying characteristics of multi-projector 3D display first and then propose a projector content synthetic method using tetrahedral transform. A 3D video format that based on stereo image pair and associated disparity map is presented, it is well suit for any type of multi-projector 3D display and has advantage in saving storage usage. Experiment results show that our method solved the pseudoscopic problem.

Research on simulation technology of full-path infrared tail flame tracking of photoelectric theodolite in complicated environment

NASA Astrophysics Data System (ADS)

Wu, Hai-ying; Zhang, San-xi; Liu, Biao; Yue, Peng; Weng, Ying-hui

2018-02-01

The photoelectric theodolite is an important scheme to realize the tracking, detection, quantitative measurement and performance evaluation of weapon systems in ordnance test range. With the improvement of stability requirements for target tracking in complex environment, infrared scene simulation with high sense of reality and complex interference has become an indispensable technical way to evaluate the track performance of photoelectric theodolite. And the tail flame is the most important infrared radiation source of the weapon system. The dynamic tail flame with high reality is a key element for the photoelectric theodolite infrared scene simulation and imaging tracking test. In this paper, an infrared simulation method for the full-path tracking of tail flame by photoelectric theodolite is proposed aiming at the faint boundary, irregular, multi-regulated points. In this work, real tail images are employed. Simultaneously, infrared texture conversion technology is used to generate DDS texture for a particle system map. Thus, dynamic real-time tail flame simulation results with high fidelity from the theodolite perspective can be gained in the tracking process.

Segmented Separable Footprint Projector for Digital Breast Tomosynthesis and Its application for Subpixel Reconstruction

PubMed Central

Zheng, Jiabei; Fessler, Jeffrey A; Chan, Heang-Ping

2017-01-01

Purpose Digital forward and back projectors play a significant role in iterative image reconstruction. The accuracy of the projector affects the quality of the reconstructed images. Digital breast tomosynthesis (DBT) often uses the ray-tracing (RT) projector that ignores finite detector element size. This paper proposes a modified version of the separable footprint (SF) projector, called the segmented separable footprint (SG) projector, that calculates efficiently the Radon transform mean value over each detector element. The SG projector is specifically designed for DBT reconstruction because of the large height-to-width ratio of the voxels generally used in DBT. This study evaluates the effectiveness of the SG projector in reducing projection error and improving DBT reconstruction quality. Methods We quantitatively compared the projection error of the RT and the SG projector at different locations and their performance in regular and subpixel DBT reconstruction. Subpixel reconstructions used finer voxels in the imaged volume than the detector pixel size. Subpixel reconstruction with RT projector uses interpolated projection views as input to provide adequate coverage of the finer voxel grid with the traced rays. Subpixel reconstruction with the SG projector, however, uses the measured projection views without interpolation. We simulated DBT projections of a test phantom using CatSim (GE Global Research, Niskayuna, NY) under idealized imaging conditions without noise and blur, to analyze the effects of the projectors and subpixel reconstruction without other image degrading factors. The phantom contained an array of horizontal and vertical line pair patterns (1 to 9.5 line pairs/mm) and pairs of closely spaced spheres (diameters 0.053 to 0.5 mm) embedded at the mid-plane of a 5-cm-thick breast-tissue-equivalent uniform volume. The images were reconstructed with regular simultaneous algebraic reconstruction technique (SART) and subpixel SART using different projectors. The resolution and contrast of the test objects in the reconstructed images and the computation times were compared under different reconstruction conditions. Results The SG projector reduced the projector error by 1 to 2 orders of magnitude at most locations. In the worst case, the SG projector still reduced the projection error by about 50%. In the DBT reconstructed slices parallel to the detector plane, the SG projector not only increased the contrast of the line pairs and spheres, but also produced more smooth and continuous reconstructed images whereas the discrete and sparse nature of the RT projector caused artifacts appearing as patterned noise. For subpixel reconstruction, the SG projector significantly increased object contrast and computation speed, especially for high subpixel ratios, compared with the RT projector implemented with accelerated Siddon’s algorithm. The difference in the depth resolution among the projectors is negligible under the conditions studied. Our results also demonstrated that subpixel reconstruction can improve the spatial resolution of the reconstructed images, and can exceed the Nyquist limit of the detector under some conditions. Conclusions The SG projector was more accurate and faster than the RT projector. The SG projector also substantially reduced computation time and improved the image quality for the tomosynthesized images with and without subpixel reconstruction. PMID:28058719

Real-time range acquisition by adaptive structured light.

PubMed

Koninckx, Thomas P; Van Gool, Luc

2006-03-01

The goal of this paper is to provide a "self-adaptive" system for real-time range acquisition. Reconstructions are based on a single frame structured light illumination. Instead of using generic, static coding that is supposed to work under all circumstances, system adaptation is proposed. This occurs on-the-fly and renders the system more robust against instant scene variability and creates suitable patterns at startup. A continuous trade-off between speed and quality is made. A weighted combination of different coding cues--based upon pattern color, geometry, and tracking--yields a robust way to solve the correspondence problem. The individual coding cues are automatically adapted within a considered family of patterns. The weights to combine them are based on the average consistency with the result within a small time-window. The integration itself is done by reformulating the problem as a graph cut. Also, the camera-projector configuration is taken into account for generating the projection patterns. The correctness of the range maps is not guaranteed, but an estimation of the uncertainty is provided for each part of the reconstruction. Our prototype is implemented using unmodified consumer hardware only and, therefore, is cheap. Frame rates vary between 10 and 25 fps, dependent on scene complexity.

Media Manual (How to Use Media Equipment).

ERIC Educational Resources Information Center

Jones, Nancy

Using a workbook format, this guide explains the use of seven types of audiovisual equipment: overhead projector, Bell and Howell 16mm motion picture projector, Dukane filmstrip projector, record player, Kodak slide projector, Wollensak 2552 tape recorder, and JVC videocassette color video system. An introductory section includes (1) a media…

Self-adaptive calibration for staring infrared sensors

NASA Astrophysics Data System (ADS)

Kendall, William B.; Stocker, Alan D.

1993-10-01

This paper presents a new, self-adaptive technique for the correlation of non-uniformities (fixed-pattern noise) in high-density infrared focal-plane detector arrays. We have developed a new approach to non-uniformity correction in which we use multiple image frames of the scene itself, and take advantage of the aim-point wander caused by jitter, residual tracking errors, or deliberately induced motion. Such wander causes each detector in the array to view multiple scene elements, and each scene element to be viewed by multiple detectors. It is therefore possible to formulate (and solve) a set of simultaneous equations from which correction parameters can be computed for the detectors. We have tested our approach with actual images collected by the ARPA-sponsored MUSIC infrared sensor. For these tests we employed a 60-frame (0.75-second) sequence of terrain images for which an out-of-date calibration was deliberately used. The sensor was aimed at a point on the ground via an operator-assisted tracking system having a maximum aim point wander on the order of ten pixels. With these data, we were able to improve the calibration accuracy by a factor of approximately 100.

A high-resolution three-dimensional far-infrared thermal and true-color imaging system for medical applications.

PubMed

Cheng, Victor S; Bai, Jinfen; Chen, Yazhu

2009-11-01

As the needs for various kinds of body surface information are wide-ranging, we developed an imaging-sensor integrated system that can synchronously acquire high-resolution three-dimensional (3D) far-infrared (FIR) thermal and true-color images of the body surface. The proposed system integrates one FIR camera and one color camera with a 3D structured light binocular profilometer. To eliminate the emotion disturbance of the inspector caused by the intensive light projection directly into the eye from the LCD projector, we have developed a gray encoding strategy based on the optimum fringe projection layout. A self-heated checkerboard has been employed to perform the calibration of different types of cameras. Then, we have calibrated the structured light emitted by the LCD projector, which is based on the stereo-vision idea and the least-squares quadric surface-fitting algorithm. Afterwards, the precise 3D surface can fuse with undistorted thermal and color images. To enhance medical applications, the region-of-interest (ROI) in the temperature or color image representing the surface area of clinical interest can be located in the corresponding position in the other images through coordinate system transformation. System evaluation demonstrated a mapping error between FIR and visual images of three pixels or less. Experiments show that this work is significantly useful in certain disease diagnoses.

Smart windows with functions of reflective display and indoor temperature-control

NASA Astrophysics Data System (ADS)

Lee, I.-Hui; Chao, Yu-Ching; Hsu, Chih-Cheng; Chang, Liang-Chao; Chiu, Tien-Lung; Lee, Jiunn-Yih; Kao, Fu-Jen; Lee, Chih-Kung; Lee, Jiun-Haw

2010-02-01

In this paper, a switchable window based on cholestreric liquid crystal (CLC) was demonstrated. Under different applied voltages, incoming light at visible and infrared wavelengths was modulated, respectively. A mixture of CLC with a nematic liquid crystal and a chiral dopant selectively reflected infrared light without bias, which effectively reduced the indoor temperature under sunlight illumination. At this time, transmission at visible range was kept at high and the windows looked transparent. With increasing the voltage to 15V, CLC changed to focal conic state and can be used as a reflective display, a privacy window, or a screen for projector. Under a high voltage (30V), homeotropic state was achieved. At this time, both infrared and visible light can transmit which acted as a normal window, which permitted infrared spectrum of winter sunlight to enter the room so as to reduce the heating requirement. Such a device can be used as a switchable window in smart buildings, green houses and windshields.

Using a Video Projector for Color-Mixing Demonstrations.

ERIC Educational Resources Information Center

Bartels, Richard A.

1982-01-01

Suggestions are provided for using color television projector systems to demonstrate color mixing. With such a projector, manipulation of the three primary colors can be done by simply covering and uncovering the three separate beams. In addition, projector systems serve as good examples in studying geometrical optics. (Author/JN)

The review on infrared image restoration techniques

NASA Astrophysics Data System (ADS)

Li, Sijian; Fan, Xiang; Zhu, Bin Cheng; Zheng, Dong

2016-11-01

The goal of infrared image restoration is to reconstruct an original scene from a degraded observation. The restoration process in the application of infrared wavelengths, however, still has numerous research possibilities. In order to give people a comprehensive knowledge of infrared image restoration, the degradation factors divided into two major categories of noise and blur. Many kinds of infrared image restoration method were overviewed. Mathematical background and theoretical basis of infrared image restoration technology, and the limitations or insufficiency of existing methods were discussed. After the survey, the direction and prospects of infrared image restoration technology for the future development were forecast and put forward.

Image based performance analysis of thermal imagers

NASA Astrophysics Data System (ADS)

Wegner, D.; Repasi, E.

2016-05-01

Due to advances in technology, modern thermal imagers resemble sophisticated image processing systems in functionality. Advanced signal and image processing tools enclosed into the camera body extend the basic image capturing capability of thermal cameras. This happens in order to enhance the display presentation of the captured scene or specific scene details. Usually, the implemented methods are proprietary company expertise, distributed without extensive documentation. This makes the comparison of thermal imagers especially from different companies a difficult task (or at least a very time consuming/expensive task - e.g. requiring the execution of a field trial and/or an observer trial). For example, a thermal camera equipped with turbulence mitigation capability stands for such a closed system. The Fraunhofer IOSB has started to build up a system for testing thermal imagers by image based methods in the lab environment. This will extend our capability of measuring the classical IR-system parameters (e.g. MTF, MTDP, etc.) in the lab. The system is set up around the IR- scene projector, which is necessary for the thermal display (projection) of an image sequence for the IR-camera under test. The same set of thermal test sequences might be presented to every unit under test. For turbulence mitigation tests, this could be e.g. the same turbulence sequence. During system tests, gradual variation of input parameters (e. g. thermal contrast) can be applied. First ideas of test scenes selection and how to assembly an imaging suite (a set of image sequences) for the analysis of imaging thermal systems containing such black boxes in the image forming path is discussed.

Real-time maritime scene simulation for ladar sensors

NASA Astrophysics Data System (ADS)

Christie, Chad L.; Gouthas, Efthimios; Swierkowski, Leszek; Williams, Owen M.

2011-06-01

Continuing interest exists in the development of cost-effective synthetic environments for testing Laser Detection and Ranging (ladar) sensors. In this paper we describe a PC-based system for real-time ladar scene simulation of ships and small boats in a dynamic maritime environment. In particular, we describe the techniques employed to generate range imagery accompanied by passive radiance imagery. Our ladar scene generation system is an evolutionary extension of the VIRSuite infrared scene simulation program and includes all previous features such as ocean wave simulation, the physically-realistic representation of boat and ship dynamics, wake generation and simulation of whitecaps, spray, wake trails and foam. A terrain simulation extension is also under development. In this paper we outline the development, capabilities and limitations of the VIRSuite extensions.

Infrared small target detection in heavy sky scene clutter based on sparse representation

NASA Astrophysics Data System (ADS)

Liu, Depeng; Li, Zhengzhou; Liu, Bing; Chen, Wenhao; Liu, Tianmei; Cao, Lei

2017-09-01

A novel infrared small target detection method based on sky clutter and target sparse representation is proposed in this paper to cope with the representing uncertainty of clutter and target. The sky scene background clutter is described by fractal random field, and it is perceived and eliminated via the sparse representation on fractal background over-complete dictionary (FBOD). The infrared small target signal is simulated by generalized Gaussian intensity model, and it is expressed by the generalized Gaussian target over-complete dictionary (GGTOD), which could describe small target more efficiently than traditional structured dictionaries. Infrared image is decomposed on the union of FBOD and GGTOD, and the sparse representation energy that target signal and background clutter decomposed on GGTOD differ so distinctly that it is adopted to distinguish target from clutter. Some experiments are induced and the experimental results show that the proposed approach could improve the small target detection performance especially under heavy clutter for background clutter could be efficiently perceived and suppressed by FBOD and the changing target could also be represented accurately by GGTOD.

Experiment research on infrared targets signature in mid and long IR spectral bands

NASA Astrophysics Data System (ADS)

Wang, Chensheng; Hong, Pu; Lei, Bo; Yue, Song; Zhang, Zhijie; Ren, Tingting

2013-09-01

Since the infrared imaging system has played a significant role in the military self-defense system and fire control system, the radiation signature of IR target becomes an important topic in IR imaging application technology. IR target signature can be applied in target identification, especially for small and dim targets, as well as the target IR thermal design. To research and analyze the targets IR signature systematically, a practical and experimental project is processed under different backgrounds and conditions. An infrared radiation acquisition system based on a MWIR cooled thermal imager and a LWIR cooled thermal imager is developed to capture the digital infrared images. Furthermore, some instruments are introduced to provide other parameters. According to the original image data and the related parameters in a certain scene, the IR signature of interested target scene can be calculated. Different background and targets are measured with this approach, and a comparison experiment analysis shall be presented in this paper as an example. This practical experiment has proved the validation of this research work, and it is useful in detection performance evaluation and further target identification research.

The Wide-Field Imaging Interferometry Testbed (WIIT): Recent Progress in the Simulation and Synthesis of WIIT Data

NASA Technical Reports Server (NTRS)

Juanola Parramon, Roser; Leisawitz, David T.; Bolcar, Matthew R.; Maher, Stephen F.; Rinehart, Stephen A.; Iacchetta, Alex; Savini, Giorgio

2016-01-01

The Wide-field Imaging Interferometry Testbed (WIIT) is a double Fourier (DF) interferometer operating at optical wavelengths, and provides data that are highly representative of those from a space-based far-infrared interferometer like SPIRIT. This testbed has been used to measure both a geometrically simple test scene and an astronomically representative test scene. Here we present the simulation of recent WIIT measurements using FIInS (the Far-infrared Interferometer Instrument Simulator), the main goal of which is to simulate both the input and the output of a DFM system. FIInS has been modified to perform calculations at optical wavelengths and to include an extended field of view due to the presence of a detector array.

Micromachined single-level nonplanar polycrystalline SiGe thermal microemitters for infrared dynamic scene projection

NASA Astrophysics Data System (ADS)

Malyutenko, V. K.; Malyutenko, O. Yu.; Leonov, V.; Van Hoof, C.

2009-05-01

The technology for self-supported membraneless polycrystalline SiGe thermal microemitters, their design, and performance are presented. The 128-element arrays with a fill factor of 88% and a 2.5-μm-thick resonant cavity have been grown by low-pressure chemical vapor deposition and fabricated using surface micromachining technology. The 200-nm-thick 60×60 μm2 emitting pixels enforced with a U-shape profile pattern demonstrate a thermal time constant of 2-7 ms and an apparent temperature of 700 K in the 3-5 and 8-12 μm atmospheric transparency windows. The application of the devices to the infrared dynamic scene simulation and their benefit over conventional planar membrane-supported emitters are discussed.

Color Infrared view of Houston, TX, USA

NASA Image and Video Library

1991-09-18

This color infrared view of Houston (29.5N, 95.0W) was taken with a dual camera mount. Compare this scene with STS048-78-034 for an analysis of the unique properties of each film type. Comparative tests such as this aids in determining the kinds of information unique to each film system and evaluates and compares photography taken through hazy atmospheres. Infrared film is best at penetrating haze, vegetation detection and producing a sharp image.

Fast 3D NIR systems for facial measurement and lip-reading

NASA Astrophysics Data System (ADS)

Brahm, Anika; Ramm, Roland; Heist, Stefan; Rulff, Christian; Kühmstedt, Peter; Notni, Gunther

2017-05-01

Structured-light projection is a well-established optical method for the non-destructive contactless three-dimensional (3D) measurement of object surfaces. In particular, there is a great demand for accurate and fast 3D scans of human faces or facial regions of interest in medicine, safety, face modeling, games, virtual life, or entertainment. New developments of facial expression detection and machine lip-reading can be used for communication tasks, future machine control, or human-machine interactions. In such cases, 3D information may offer more detailed information than 2D images which can help to increase the power of current facial analysis algorithms. In this contribution, we present new 3D sensor technologies based on three different methods of near-infrared projection technologies in combination with a stereo vision setup of two cameras. We explain the optical principles of an NIR GOBO projector, an array projector and a modified multi-aperture projection method and compare their performance parameters to each other. Further, we show some experimental measurement results of applications where we realized fast, accurate, and irritation-free measurements of human faces.

Multi-Octave Spectral Imaging in the Infrared - A Newly Emerging Approach

DTIC Science & Technology

2002-01-01

as a function of wavelength, that arises from an example scene, and compare this with total noise (also as a function of wavelength). The signal...0.9 emissivity, for the purpose of this estimate of baseline performance. Total noise (in rms electrons) is estimated as a function of wavelength (or...spectral pixel number following the correspondence in Figure 2) from photon noise arising from both scene and optics emission, dark current noise , and

Out-of-Focus Projector Calibration Method with Distortion Correction on the Projection Plane in the Structured Light Three-Dimensional Measurement System.

PubMed

Zhang, Jiarui; Zhang, Yingjie; Chen, Bo

2017-12-20

The three-dimensional measurement system with a binary defocusing technique is widely applied in diverse fields. The measurement accuracy is mainly determined by out-of-focus projector calibration accuracy. In this paper, a high-precision out-of-focus projector calibration method that is based on distortion correction on the projection plane and nonlinear optimization algorithm is proposed. To this end, the paper experimentally presents the principle that the projector has noticeable distortions outside its focus plane. In terms of this principle, the proposed method uses a high-order radial and tangential lens distortion representation on the projection plane to correct the calibration residuals caused by projection distortion. The final accuracy parameters of out-of-focus projector were obtained using a nonlinear optimization algorithm with good initial values, which were provided by coarsely calibrating the parameters of the out-of-focus projector on the focal and projection planes. Finally, the experimental results demonstrated that the proposed method can accuracy calibrate an out-of-focus projector, regardless of the amount of defocusing.

Scene-based nonuniformity correction for focal plane arrays by the method of the inverse covariance form.

PubMed

Torres, Sergio N; Pezoa, Jorge E; Hayat, Majeed M

2003-10-10

What is to our knowledge a new scene-based algorithm for nonuniformity correction in infrared focal-plane array sensors has been developed. The technique is based on the inverse covariance form of the Kalman filter (KF), which has been reported previously and used in estimating the gain and bias of each detector in the array from scene data. The gain and the bias of each detector in the focal-plane array are assumed constant within a given sequence of frames, corresponding to a certain time and operational conditions, but they are allowed to randomly drift from one sequence to another following a discrete-time Gauss-Markov process. The inverse covariance form filter estimates the gain and the bias of each detector in the focal-plane array and optimally updates them as they drift in time. The estimation is performed with considerably higher computational efficiency than the equivalent KF. The ability of the algorithm in compensating for fixed-pattern noise in infrared imagery and in reducing the computational complexity is demonstrated by use of both simulated and real data.

Scene-based nonuniformity correction with video sequences and registration.

PubMed

Hardie, R C; Hayat, M M; Armstrong, E; Yasuda, B

2000-03-10

We describe a new, to our knowledge, scene-based nonuniformity correction algorithm for array detectors. The algorithm relies on the ability to register a sequence of observed frames in the presence of the fixed-pattern noise caused by pixel-to-pixel nonuniformity. In low-to-moderate levels of nonuniformity, sufficiently accurate registration may be possible with standard scene-based registration techniques. If the registration is accurate, and motion exists between the frames, then groups of independent detectors can be identified that observe the same irradiance (or true scene value). These detector outputs are averaged to generate estimates of the true scene values. With these scene estimates, and the corresponding observed values through a given detector, a curve-fitting procedure is used to estimate the individual detector response parameters. These can then be used to correct for detector nonuniformity. The strength of the algorithm lies in its simplicity and low computational complexity. Experimental results, to illustrate the performance of the algorithm, include the use of visible-range imagery with simulated nonuniformity and infrared imagery with real nonuniformity.

On the Integration of Medium Wave Infrared Cameras for Vision-Based Navigation

DTIC Science & Technology

2015-03-01

SWIR Short Wave Infrared VisualSFM Visual Structure from Motion WPAFB Wright Patterson Air Force Base xi ON THE INTEGRATION OF MEDIUM WAVE INFRARED...Structure from Motion Visual Structure from Motion ( VisualSFM ) is an application that performs incremental SfM using images fed into it of a scene [20...too drastically in between frames. When this happens, VisualSFM will begin creating a new model with images that do not fit to the old one. These new

Design of a single projector multiview 3D display system

NASA Astrophysics Data System (ADS)

Geng, Jason

2014-03-01

Multiview three-dimensional (3D) display is able to provide horizontal parallax to viewers with high-resolution and fullcolor images being presented to each view. Most multiview 3D display systems are designed and implemented using multiple projectors, each generating images for one view. Although this multi-projector design strategy is conceptually straightforward, implementation of such multi-projector design often leads to a very expensive system and complicated calibration procedures. Even for a multiview system with a moderate number of projectors (e.g., 32 or 64 projectors), the cost of a multi-projector 3D display system may become prohibitive due to the cost and complexity of integrating multiple projectors. In this article, we describe an optical design technique for a class of multiview 3D display systems that use only a single projector. In this single projector multiview (SPM) system design, multiple views for the 3D display are generated in a time-multiplex fashion by the single high speed projector with specially designed optical components, a scanning mirror, and a reflective mirror array. Images of all views are generated sequentially and projected via the specially design optical system from different viewing directions towards a 3D display screen. Therefore, the single projector is able to generate equivalent number of multiview images from multiple viewing directions, thus fulfilling the tasks of multiple projectors. An obvious advantage of the proposed SPM technique is the significant reduction of cost, size, and complexity, especially when the number of views is high. The SPM strategy also alleviates the time-consuming procedures for multi-projector calibration. The design method is flexible and scalable and can accommodate systems with different number of views.

Reconstruction of crimes by infrared photography.

PubMed

Sterzik, V; Bohnert, M

2016-09-01

Whenever blunt or sharp forces are used in a crime, analysis of bloodstain pattern distribution may provide important information for the reconstruction of happenings. Thereby, attention should be paid to both the crime scene and the clothes of everyone involved in the crime. On dark textiles, though, it is difficult or even impossible for the human eye to detect bloodstains because of the low contrast to the background. However, in the near infrared wavelength range, contrast is considerably higher. Many textiles reflect light beyond a wavelength of 830 nm and thus appear light-colored, whereas blood absorbs the light and appears dark. In our studies, a D7000 NIKON reflex camera modified for infrared photography produced high-resolution photographs visualizing even very small spatter stains on dark textiles. The equipment can be used at any crime scene or lab and provides immediately available and interpretable images. Thus, important findings can be obtained at an early stage of police investigations, as two examples (homicide and attempted homicide) illustrate.

Research on techniques for computer three-dimensional simulation of satellites and night sky

NASA Astrophysics Data System (ADS)

Yan, Guangwei; Hu, Haitao

2007-11-01

To study space attack-defense technology, a simulation of satellites is needed. We design and implement a 3d simulating system of satellites. The satellites are rendered under the Night sky background. The system structure is as follows: one computer is used to simulate the orbital of satellites, the other computers are used to render 3d simulation scene. To get a realistic effect, a three-channel multi-projector display system is constructed. We use MultiGen Creator to construct satellite and star models. We use MultiGen Distributed Vega to render the three-channel scene. There are one master and three slaves. The master controls the three slaves to render three channels separately. To get satellites' positions and attitudes, the master communicates with the satellite orbit simulator based on TCP/IP protocol. Then it calculates the observer's position, the satellites' position, the moon's and the sun's position and transmits the data to the slaves. To get a smooth orbit of target satellites, an orbit prediction method is used. Because the target satellite data packets and the attack satellite data packets cannot keep synchronization in the network, a target satellite dithering phenomenon will occur when the scene is rendered. To resolve this problem, an anti-dithering algorithm is designed. To render Night sky background, a file which stores stars' position and brightness data is used. According to the brightness of each star, the stars are classified into different magnitude. The star model is scaled according to the magnitude. All the stars are distributed on a celestial sphere. Experiments show, the whole system can run correctly, and the frame rate can reach 30Hz. The system can be used in a space attack-defense simulation field.

A simple and low-cost structured illumination microscopy using a pico-projector

NASA Astrophysics Data System (ADS)

Özgürün, Baturay

2018-02-01

Here, development of a low-cost structured illumination microscopy (SIM) based on a pico-projector is presented. The pico-projector consists of independent red, green and blue LEDs that remove need for an external illumination source. Moreover, display element of the pico-projector serves as a pattern generating spatial light modulator. A simple lens group is employed to couple light from the projector to an epi-illumination port of a commercial microscope system. 2D sub SIM images are acquired and synthesized to surpass the diffraction limit using 40x (0.75 NA) objective. Resolution of the reconstructed SIM images is verified with a dye-and-object object and a fixed cell sample.

Radiometrically accurate scene-based nonuniformity correction for array sensors.

PubMed

Ratliff, Bradley M; Hayat, Majeed M; Tyo, J Scott

2003-10-01

A novel radiometrically accurate scene-based nonuniformity correction (NUC) algorithm is described. The technique combines absolute calibration with a recently reported algebraic scene-based NUC algorithm. The technique is based on the following principle: First, detectors that are along the perimeter of the focal-plane array are absolutely calibrated; then the calibration is transported to the remaining uncalibrated interior detectors through the application of the algebraic scene-based algorithm, which utilizes pairs of image frames exhibiting arbitrary global motion. The key advantage of this technique is that it can obtain radiometric accuracy during NUC without disrupting camera operation. Accurate estimates of the bias nonuniformity can be achieved with relatively few frames, which can be fewer than ten frame pairs. Advantages of this technique are discussed, and a thorough performance analysis is presented with use of simulated and real infrared imagery.

Phoenix, AZ, USA

NASA Image and Video Library

1973-06-22

SL2-03-200 (22 June 1973) --- The city of Phoenix, AZ (33.5N, 112.0W) can be seen in good detail in this color infrared scene. Situated among truck crop agriculture fields, the color infrared photo depicts the vegetated fields as shades of red making the agriculture stand out in this desert environment. To the east, Lake Theodore Roosevelt and dam can be easily seen. Photo credit: NASA

Adaptive convergence nonuniformity correction algorithm.

PubMed

Qian, Weixian; Chen, Qian; Bai, Junqi; Gu, Guohua

2011-01-01

Nowadays, convergence and ghosting artifacts are common problems in scene-based nonuniformity correction (NUC) algorithms. In this study, we introduce the idea of space frequency to the scene-based NUC. Then the convergence speed factor is presented, which can adaptively change the convergence speed by a change of the scene dynamic range. In fact, the convergence speed factor role is to decrease the statistical data standard deviation. The nonuniformity space relativity characteristic was summarized by plenty of experimental statistical data. The space relativity characteristic was used to correct the convergence speed factor, which can make it more stable. Finally, real and simulated infrared image sequences were applied to demonstrate the positive effect of our algorithm.

Diode Lasers and Light Emitting Diodes Operating at Room Temperature with Wavelengths Above 3 Micrometers

DTIC Science & Technology

2011-11-29

as an active region of mid - infrared LEDs. It should be noted that active region based on interband transition is equally useful for both laser and...IR LED technology for infrared scene projectors”, Dr. E. Golden, Air Force Research Laboratory, Eglin Air Force Base .  “A stable mid -IR, GaSb...multimode lasers. Single spatial mode 3-3.2 J.lm diode lasers were developed. LEDs operate at wavelength above 4 J.lm at RT. Dual color mid - infrared

Overhead Projector Spectrum of Polymethine Dye: A Physical Chemistry Demonstration

NASA Astrophysics Data System (ADS)

Solomon, Sally; Hur, Chinhyu

1995-08-01

The position of the predominant peak of 1,1'-diethyl-4,4'-cyanine iodide is measured in class using an overhead projector spectrometer, then predicted using the model of a particle-in a one dimensional box. The calculated wavelength is in excellent agreement with the wavelength estimated from the overhead projector spectroscopy experiment.

Growing Crystals on the Ceiling.

ERIC Educational Resources Information Center

Christman, Robert A.

1980-01-01

Described is a method of studying growing crystals in a classroom utilizing a carrousel projector standing vertically. A saturated salt solution is placed on a slide on the lens of the projector and the heat from the projector causes the water to evaporate and salt to crystalize. (Author/DS)

Method and apparatus for coherent imaging of infrared energy

DOEpatents

Hutchinson, Donald P.

1998-01-01

A coherent camera system performs ranging, spectroscopy, and thermal imaging. Local oscillator radiation is combined with target scene radiation to enable heterodyne detection by the coherent camera's two-dimensional photodetector array. Versatility enables deployment of the system in either a passive mode (where no laser energy is actively transmitted toward the target scene) or an active mode (where a transmitting laser is used to actively illuminate the target scene). The two-dimensional photodetector array eliminates the need to mechanically scan the detector. Each element of the photodetector array produces an intermediate frequency signal that is amplified, filtered, and rectified by the coherent camera's integrated circuitry. By spectroscopic examination of the frequency components of each pixel of the detector array, a high-resolution, three-dimensional or holographic image of the target scene is produced for applications such as air pollution studies, atmospheric disturbance monitoring, and military weapons targeting.

Method and apparatus for coherent imaging of infrared energy

DOEpatents

Hutchinson, D.P.

1998-05-12

A coherent camera system performs ranging, spectroscopy, and thermal imaging. Local oscillator radiation is combined with target scene radiation to enable heterodyne detection by the coherent camera`s two-dimensional photodetector array. Versatility enables deployment of the system in either a passive mode (where no laser energy is actively transmitted toward the target scene) or an active mode (where a transmitting laser is used to actively illuminate the target scene). The two-dimensional photodetector array eliminates the need to mechanically scan the detector. Each element of the photodetector array produces an intermediate frequency signal that is amplified, filtered, and rectified by the coherent camera`s integrated circuitry. By spectroscopic examination of the frequency components of each pixel of the detector array, a high-resolution, three-dimensional or holographic image of the target scene is produced for applications such as air pollution studies, atmospheric disturbance monitoring, and military weapons targeting. 8 figs.

Implementation of jump-diffusion algorithms for understanding FLIR scenes

NASA Astrophysics Data System (ADS)

Lanterman, Aaron D.; Miller, Michael I.; Snyder, Donald L.

1995-07-01

Our pattern theoretic approach to the automated understanding of forward-looking infrared (FLIR) images brings the traditionally separate endeavors of detection, tracking, and recognition together into a unified jump-diffusion process. New objects are detected and object types are recognized through discrete jump moves. Between jumps, the location and orientation of objects are estimated via continuous diffusions. An hypothesized scene, simulated from the emissive characteristics of the hypothesized scene elements, is compared with the collected data by a likelihood function based on sensor statistics. This likelihood is combined with a prior distribution defined over the set of possible scenes to form a posterior distribution. The jump-diffusion process empirically generates the posterior distribution. Both the diffusion and jump operations involve the simulation of a scene produced by a hypothesized configuration. Scene simulation is most effectively accomplished by pipelined rendering engines such as silicon graphics. We demonstrate the execution of our algorithm on a silicon graphics onyx/reality engine.

The Development of a Computer Controlled Super 8 Motion Picture Projector.

ERIC Educational Resources Information Center

Reynolds, Eldon J.

Instructors in Child Development at the University of Texas at Austin selected sound motion pictures as the most effective medium to simulate the observation of children in nursery laboratories. A computer controlled projector was designed for this purpose. An interface and control unit controls the Super 8 projector from a time-sharing computer…

Improving AIRS Radiance Spectra in High Contrast Scenes Using MODIS

NASA Technical Reports Server (NTRS)

Pagano, Thomas S.; Aumann, Hartmut H.; Manning, Evan M.; Elliott, Denis A.; Broberg, Steven E.

2015-01-01

The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in 2378 channels ranging in wavelength from 3.7-15.4 microns with spectral resolution of better than 1200, and spatial resolution of 13.5 km with global daily coverage. The AIRS is designed to measure temperature and water vapor profiles for improvement in weather forecast accuracy and improved understanding of climate processes. As with most instruments, the AIRS Point Spread Functions (PSFs) are not the same for all detectors. When viewing a non-uniform scene, this causes a significant radiometric error in some channels that is scene dependent and cannot be removed without knowledge of the underlying scene. The magnitude of the error depends on the combination of non-uniformity of the AIRS spatial response for a given channel and the non-uniformity of the scene, but is typically only noticeable in about 1% of the scenes and about 10% of the channels. The current solution is to avoid those channels when performing geophysical retrievals. In this effort we use data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument to provide information on the scene uniformity that is used to correct the AIRS data. For the vast majority of channels and footprints the technique works extremely well when compared to a Principal Component (PC) reconstruction of the AIRS channels. In some cases where the scene has high inhomogeneity in an irregular pattern, and in some channels, the method can actually degrade the spectrum. Most of the degraded channels appear to be slightly affected by random noise introduced in the process, but those with larger degradation may be affected by alignment errors in the AIRS relative to MODIS or uncertainties in the PSF. Despite these errors, the methodology shows the ability to correct AIRS radiances in non-uniform scenes under some of the worst case conditions and improves the ability to match AIRS and MODIS radiances in non-uniform scenes.

Evaluating the effect of spatial subsetting on subpixel unmixing methodology applied to ASTER over a hydrothermally altered terrain

NASA Astrophysics Data System (ADS)

Ayoobi, Iman; Tangestani, Majid H.

2017-10-01

This study investigates the effect of spatial subsets of Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) L1B visible-near infrared and short wave-infrared (VNIR-SWIR) data on matched filtering results at the central part of Kerman magmatic arc, where abundant porphyry copper deposits exist. The matched filtering (MF) procedure was run separately at sites containing hydrothermal minerals such as sericite, kaolinite, chlorite, and jarosite to map the abundances of these minerals on spatial subsets containing 100, 75, 50, and 25 percent of the original scene. Results were evaluated by comparing the matched filtering scores with the mineral abundances obtained by semi-quantitative XRD analysis of corresponding field samples. It was concluded that MF method should be applied to the whole scene prior to any data subsetting.

Quantitative image fusion in infrared radiometry

NASA Astrophysics Data System (ADS)

Romm, Iliya; Cukurel, Beni

2018-05-01

Towards high-accuracy infrared radiance estimates, measurement practices and processing techniques aimed to achieve quantitative image fusion using a set of multi-exposure images of a static scene are reviewed. The conventional non-uniformity correction technique is extended, as the original is incompatible with quantitative fusion. Recognizing the inherent limitations of even the extended non-uniformity correction, an alternative measurement methodology, which relies on estimates of the detector bias using self-calibration, is developed. Combining data from multi-exposure images, two novel image fusion techniques that ultimately provide high tonal fidelity of a photoquantity are considered: ‘subtract-then-fuse’, which conducts image subtraction in the camera output domain and partially negates the bias frame contribution common to both the dark and scene frames; and ‘fuse-then-subtract’, which reconstructs the bias frame explicitly and conducts image fusion independently for the dark and the scene frames, followed by subtraction in the photoquantity domain. The performances of the different techniques are evaluated for various synthetic and experimental data, identifying the factors contributing to potential degradation of the image quality. The findings reflect the superiority of the ‘fuse-then-subtract’ approach, conducting image fusion via per-pixel nonlinear weighted least squares optimization.

Scene-based nonuniformity correction with reduced ghosting using a gated LMS algorithm.

PubMed

Hardie, Russell C; Baxley, Frank; Brys, Brandon; Hytla, Patrick

2009-08-17

In this paper, we present a scene-based nouniformity correction (NUC) method using a modified adaptive least mean square (LMS) algorithm with a novel gating operation on the updates. The gating is designed to significantly reduce ghosting artifacts produced by many scene-based NUC algorithms by halting updates when temporal variation is lacking. We define the algorithm and present a number of experimental results to demonstrate the efficacy of the proposed method in comparison to several previously published methods including other LMS and constant statistics based methods. The experimental results include simulated imagery and a real infrared image sequence. We show that the proposed method significantly reduces ghosting artifacts, but has a slightly longer convergence time. (c) 2009 Optical Society of America

A High Spatial Resolution Depth Sensing Method Based on Binocular Structured Light

PubMed Central

Yao, Huimin; Ge, Chenyang; Xue, Jianru; Zheng, Nanning

2017-01-01

Depth information has been used in many fields because of its low cost and easy availability, since the Microsoft Kinect was released. However, the Kinect and Kinect-like RGB-D sensors show limited performance in certain applications and place high demands on accuracy and robustness of depth information. In this paper, we propose a depth sensing system that contains a laser projector similar to that used in the Kinect, and two infrared cameras located on both sides of the laser projector, to obtain higher spatial resolution depth information. We apply the block-matching algorithm to estimate the disparity. To improve the spatial resolution, we reduce the size of matching blocks, but smaller matching blocks generate lower matching precision. To address this problem, we combine two matching modes (binocular mode and monocular mode) in the disparity estimation process. Experimental results show that our method can obtain higher spatial resolution depth without loss of the quality of the range image, compared with the Kinect. Furthermore, our algorithm is implemented on a low-cost hardware platform, and the system can support the resolution of 1280 × 960, and up to a speed of 60 frames per second, for depth image sequences. PMID:28397759

Maximum Likelihood Detection of Electro-Optic Moving Targets

DTIC Science & Technology

1992-01-16

indicates intensity. The Infrared Measurements Sensor (IRMS) is a scanning sensor that collects both long wave- length infrared ( LWIR , 8 to 12 fim...moving clutter. Nonstationary spatial statistics correspond to the nonuniform intensity of the background scene. An equivalent viewpoint is to...Figure 6 compares theory and experiment for 10 frames of the Longjump LWIR data obtained from the IRMS scanning sensor, which is looking at a background

New technologies for HWIL testing of WFOV, large-format FPA sensor systems

NASA Astrophysics Data System (ADS)

Fink, Christopher

2016-05-01

Advancements in FPA density and associated wide-field-of-view infrared sensors (>=4000x4000 detectors) have outpaced the current-art HWIL technology. Whether testing in optical projection or digital signal injection modes, current-art technologies for infrared scene projection, digital injection interfaces, and scene generation systems simply lack the required resolution and bandwidth. For example, the L3 Cincinnati Electronics ultra-high resolution MWIR Camera deployed in some UAV reconnaissance systems features 16MP resolution at 60Hz, while the current upper limit of IR emitter arrays is ~1MP, and single-channel dual-link DVI throughput of COTs graphics cards is limited to 2560x1580 pixels at 60Hz. Moreover, there are significant challenges in real-time, closed-loop, physics-based IR scene generation for large format FPAs, including the size and spatial detail required for very large area terrains, and multi - channel low-latency synchronization to achieve the required bandwidth. In this paper, the author's team presents some of their ongoing research and technical approaches toward HWIL testing of large-format FPAs with wide-FOV optics. One approach presented is a hybrid projection/injection design, where digital signal injection is used to augment the resolution of current-art IRSPs, utilizing a multi-channel, high-fidelity physics-based IR scene simulator in conjunction with a novel image composition hardware unit, to allow projection in the foveal region of the sensor, while non-foveal regions of the sensor array are simultaneously stimulated via direct injection into the post-detector electronics.

The Use of a Computer-Controlled Random Access Slide Projector for Rapid Information Display.

ERIC Educational Resources Information Center

Muller, Mark T.

A 35mm random access slide projector operated in conjunction with a computer terminal was adapted to meet the need for a more rapid and complex graphic display mechanism than is currently available with teletypewriter terminals. The model projector can be operated manually to provide for a maintenance checkout of the electromechanical system.…

Bulletin Boards and 3-D Showcases That Capture Them with Pizzazz. Volume 2.

ERIC Educational Resources Information Center

Hawthorne, Karen; Gibson, Jane E.

This book features bulletin boards and showcases, designed to motivate readers to use the library, that have been the favorites of students in grades 7-12. Chapter 1 covers getting started, including principles of design, tools of design, background, borders, letters, leaves and flowers, opaque projector/overhead projector/document projector,…

Modelling Middle Infrared Thermal Imagery from Observed or Simulated Active Fire

NASA Astrophysics Data System (ADS)

Paugam, R.; Gastellu-Etchegorry, J. P.; Mell, W.; Johnston, J.; Filippi, J. B.

2016-12-01

The Fire Radiative Power (FRP) is used in the atmospheric and fire communities to estimate fire emission. For example, the current version of the emission inventory GFAS is using FRP observation from the MODIS sensors to derive daily global distribution of fire emissions. Although the FRP product is widely accepted, most of its theoretical justifications are still based on small scale burns. When up-scaling to large fires effects of view angle, canopy cover, or smoke absorption are still unknown. To cover those questions, we are building a system based on the DART radiative transfer model to simulate the middle infrared radiance emitted by a propagating fire front and propagating in the surrounding scene made of ambient vegetation and plume aerosols. The current version of the system was applied to fire ranging from a 1m2 to 7ha. The 3D fire scene used as input in DART is made of the flame, the vegetation (burnt and unburnt), and the plume. It can be either set up from [i] 3D physical based model scene (ie WFDS, mainly applicable for small scale burn), [ii] coupled 2D fire spread - atmospheric models outputs (eg ForeFire-MesoNH) or [iii] derived from thermal imageries observations (here plume effects are not considered). In the last two cases, as the complexity of physical processes occurring in the flame (in particular soot formation and emission) is not to solved, the flames structures are parameterized with (a) temperature and soot concentration based on empirical derived profiles and (b) 3D triangular shape hull interpolated at the fire front location. Once the 3D fire scene is set up, DART is then used to render thermal imageries in the middle infrared. Using data collected from burns conducted at different scale, the modelled thermal imageries are compared against observations, and effects of view angle are discussed.

Scene-based nonuniformity corrections for optical and SWIR pushbroom sensors.

PubMed

Leathers, Robert; Downes, Trijntje; Priest, Richard

2005-06-27

We propose and evaluate several scene-based methods for computing nonuniformity corrections for visible or near-infrared pushbroom sensors. These methods can be used to compute new nonuniformity correction values or to repair or refine existing radiometric calibrations. For a given data set, the preferred method depends on the quality of the data, the type of scenes being imaged, and the existence and quality of a laboratory calibration. We demonstrate our methods with data from several different sensor systems and provide a generalized approach to be taken for any new data set.

An algebraic algorithm for nonuniformity correction in focal-plane arrays.

PubMed

Ratliff, Bradley M; Hayat, Majeed M; Hardie, Russell C

2002-09-01

A scene-based algorithm is developed to compensate for bias nonuniformity in focal-plane arrays. Nonuniformity can be extremely problematic, especially for mid- to far-infrared imaging systems. The technique is based on use of estimates of interframe subpixel shifts in an image sequence, in conjunction with a linear-interpolation model for the motion, to extract information on the bias nonuniformity algebraically. The performance of the proposed algorithm is analyzed by using real infrared and simulated data. One advantage of this technique is its simplicity; it requires relatively few frames to generate an effective correction matrix, thereby permitting the execution of frequent on-the-fly nonuniformity correction as drift occurs. Additionally, the performance is shown to exhibit considerable robustness with respect to lack of the common types of temporal and spatial irradiance diversity that are typically required by statistical scene-based nonuniformity correction techniques.

Robust Approach for Nonuniformity Correction in Infrared Focal Plane Array

PubMed Central

Boutemedjet, Ayoub; Deng, Chenwei; Zhao, Baojun

2016-01-01

In this paper, we propose a new scene-based nonuniformity correction technique for infrared focal plane arrays. Our work is based on the use of two well-known scene-based methods, namely, adaptive and interframe registration-based exploiting pure translation motion model between frames. The two approaches have their benefits and drawbacks, which make them extremely effective in certain conditions and not adapted for others. Following on that, we developed a method robust to various conditions, which may slow or affect the correction process by elaborating a decision criterion that adapts the process to the most effective technique to ensure fast and reliable correction. In addition to that, problems such as bad pixels and ghosting artifacts are also dealt with to enhance the overall quality of the correction. The performance of the proposed technique is investigated and compared to the two state-of-the-art techniques cited above. PMID:27834893

Laboratory Measurement of the Brighter-fatter Effect in an H2RG Infrared Detector

NASA Astrophysics Data System (ADS)

Plazas, A. A.; Shapiro, C.; Smith, R.; Huff, E.; Rhodes, J.

2018-06-01

The “brighter-fatter” (BF) effect is a phenomenon—originally discovered in charge coupled devices—in which the size of the detector point-spread function (PSF) increases with brightness. We present, for the first time, laboratory measurements demonstrating the existence of the effect in a Hawaii-2RG HgCdTe near-infrared (NIR) detector. We use JPL’s Precision Projector Laboratory, a facility for emulating astronomical observations with UV/VIS/NIR detectors, to project about 17,000 point sources onto the detector to stimulate the effect. After calibrating the detector for nonlinearity with flat-fields, we find evidence that charge is nonlinearly shifted from bright pixels to neighboring pixels during exposures of point sources, consistent with the existence of a BF-type effect. NASAs Wide Field Infrared Survey Telescope (WFIRST) will use similar detectors to measure weak gravitational lensing from the shapes of hundreds of million of galaxies in the NIR. The WFIRST PSF size must be calibrated to ≈0.1% to avoid biased inferences of dark matter and dark energy parameters; therefore further study and calibration of the BF effect in realistic images will be crucial.

A HWIL test facility of infrared imaging laser radar using direct signal injection

NASA Astrophysics Data System (ADS)

Wang, Qian; Lu, Wei; Wang, Chunhui; Wang, Qi

2005-01-01

Laser radar has been widely used these years and the hardware-in-the-loop (HWIL) testing of laser radar become important because of its low cost and high fidelity compare with On-the-Fly testing and whole digital simulation separately. Scene generation and projection two key technologies of hardware-in-the-loop testing of laser radar and is a complicated problem because the 3D images result from time delay. The scene generation process begins with the definition of the target geometry and reflectivity and range. The real-time 3D scene generation computer is a PC based hardware and the 3D target models were modeled using 3dsMAX. The scene generation software was written in C and OpenGL and is executed to extract the Z-buffer from the bit planes to main memory as range image. These pixels contain each target position x, y, z and its respective intensity and range value. Expensive optical injection technologies of scene projection such as LDP array, VCSEL array, DMD and associated scene generation is ongoing. But the optical scene projection is complicated and always unaffordable. In this paper a cheaper test facility was described that uses direct electronic injection to provide rang images for laser radar testing. The electronic delay and pulse shaping circuits inject the scenes directly into the seeker's signal processing unit.

Infrared polarimetric sensing of oil on water

NASA Astrophysics Data System (ADS)

Chenault, David B.; Vaden, Justin P.; Mitchell, Douglas A.; DeMicco, Erik D.

2016-10-01

Infrared polarimetry is an emerging sensing modality that offers the potential for significantly enhanced contrast in situations where conventional thermal imaging falls short. Polarimetric imagery leverages the different polarization signatures that result from material differences, surface roughness quality, and geometry that are frequently different from those features that lead to thermal signatures. Imaging of the polarization in a scene can lead to enhanced understanding, particularly when materials in a scene are at thermal equilibrium. Polaris Sensor Technologies has measured the polarization signatures of oil on water in a number of different scenarios and has shown significant improvement in detection through the contrast improvement offered by polarimetry. The sensing improvement offers the promise of automated detection of oil spills and leaks for routine monitoring and accidents with the added benefit of being able to continue monitoring at night. In this paper, we describe the instrumentation, and the results of several measurement exercises in both controlled and uncontrolled conditions.

Robust Approach for Nonuniformity Correction in Infrared Focal Plane Array.

PubMed

Boutemedjet, Ayoub; Deng, Chenwei; Zhao, Baojun

2016-11-10

In this paper, we propose a new scene-based nonuniformity correction technique for infrared focal plane arrays. Our work is based on the use of two well-known scene-based methods, namely, adaptive and interframe registration-based exploiting pure translation motion model between frames. The two approaches have their benefits and drawbacks, which make them extremely effective in certain conditions and not adapted for others. Following on that, we developed a method robust to various conditions, which may slow or affect the correction process by elaborating a decision criterion that adapts the process to the most effective technique to ensure fast and reliable correction. In addition to that, problems such as bad pixels and ghosting artifacts are also dealt with to enhance the overall quality of the correction. The performance of the proposed technique is investigated and compared to the two state-of-the-art techniques cited above.

ASTER Waves

NASA Image and Video Library

2000-10-06

The pattern on the right half of this image of the Bay of Bengal is the result of two opposing wave trains colliding. This ASTER sub-scene, acquired on March 29, 2000, covers an area 18 kilometers (13 miles) wide and 15 kilometers (9 miles) long in three bands of the reflected visible and infrared wavelength region. The visible and near-infrared bands highlight surface waves due to specular reflection of sunlight off of the wave faces. http://photojournal.jpl.nasa.gov/catalog/PIA02662

Multi- and hyperspectral scene modeling

NASA Astrophysics Data System (ADS)

Borel, Christoph C.; Tuttle, Ronald F.

2011-06-01

This paper shows how to use a public domain raytracer POV-Ray (Persistence Of Vision Raytracer) to render multiand hyper-spectral scenes. The scripting environment allows automatic changing of the reflectance and transmittance parameters. The radiosity rendering mode allows accurate simulation of multiple-reflections between surfaces and also allows semi-transparent surfaces such as plant leaves. We show that POV-Ray computes occlusion accurately using a test scene with two blocks under a uniform sky. A complex scene representing a plant canopy is generated using a few lines of script. With appropriate rendering settings, shadows cast by leaves are rendered in many bands. Comparing single and multiple reflection renderings, the effect of multiple reflections is clearly visible and accounts for 25% of the overall apparent canopy reflectance in the near infrared.

Classification of high dimensional multispectral image data

NASA Technical Reports Server (NTRS)

Hoffbeck, Joseph P.; Landgrebe, David A.

1993-01-01

A method for classifying high dimensional remote sensing data is described. The technique uses a radiometric adjustment to allow a human operator to identify and label training pixels by visually comparing the remotely sensed spectra to laboratory reflectance spectra. Training pixels for material without obvious spectral features are identified by traditional means. Features which are effective for discriminating between the classes are then derived from the original radiance data and used to classify the scene. This technique is applied to Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data taken over Cuprite, Nevada in 1992, and the results are compared to an existing geologic map. This technique performed well even with noisy data and the fact that some of the materials in the scene lack absorption features. No adjustment for the atmosphere or other scene variables was made to the data classified. While the experimental results compare favorably with an existing geologic map, the primary purpose of this research was to demonstrate the classification method, as compared to the geology of the Cuprite scene.

Radiometric consistency assessment of hyperspectral infrared sounders

NASA Astrophysics Data System (ADS)

Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

2015-07-01

The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark datasets for both inter-calibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and -B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through one year of simultaneous nadir overpass (SNO) observations to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the longwave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both Polar and Tropical SNOs. The combined global SNO datasets indicate that, the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 comparison spectral regions and they range from 0.15 to 0.21 K in the remaining 4 spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

Development of an Infrared Remote Sensing System for Continuous Monitoring of Stromboli Volcano

NASA Astrophysics Data System (ADS)

Harig, R.; Burton, M.; Rausch, P.; Jordan, M.; Gorgas, J.; Gerhard, J.

2009-04-01

In order to monitor gases emitted by Stromboli volcano in the Eolian archipelago, Italy, a remote sensing system based on Fourier-transform infrared spectroscopy has been developed and installed on the summit of Stromboli volcano. Hot rocks and lava are used as sources of infrared radiation. The system is based on an interferometer with a single detector element in combination with an azimuth-elevation scanning mirror system. The mirror system is used to align the field of view of the instrument. In addition, the system is equipped with an infrared camera. Two basic modes of operation have been implemented: The user may use the infrared image to align the system to a vent that is to be examined. In addition, the scanning system may be used for (hyperspectral) imaging of the scene. In this mode, the scanning mirror is set sequentially move to all positions within a region of interest which is defined by the operator using the image generated from the infrared camera. The spectral range used for the measurements is 1600 - 4200 cm-1 allowing the quantification of many gases such as CO, CO2, SO2, and HCl. The spectral resolution is 0.5 cm-1. In order to protect the optical, mechanical and electrical parts of the system from the volcanic gases, all components are contained in a gas-tight aluminium housing. The system is controlled via TCP/IP (data transfer by WLAN), allowing the user to operate it from a remote PC. The infrared image of the scene and measured spectra are transferred to and displayed by a remote PC at INGV or TUHH in real-time. However, the system is capable of autonomous operation on the volcano, once a measurement has been started. Measurements are stored by an internal embedded PC.

Real-time synchronized multiple-sensor IR/EO scene generation utilizing the SGI Onyx2

NASA Astrophysics Data System (ADS)

Makar, Robert J.; O'Toole, Brian E.

1998-07-01

An approach to utilize the symmetric multiprocessing environment of the Silicon Graphics Inc.R (SGI) Onyx2TM has been developed to support the generation of IR/EO scenes in real-time. This development, supported by the Naval Air Warfare Center Aircraft Division (NAWC/AD), focuses on high frame rate hardware-in-the-loop testing of multiple sensor avionics systems. In the past, real-time IR/EO scene generators have been developed as custom architectures that were often expensive and difficult to maintain. Previous COTS scene generation systems, designed and optimized for visual simulation, could not be adapted for accurate IR/EO sensor stimulation. The new Onyx2 connection mesh architecture made it possible to develop a more economical system while maintaining the fidelity needed to stimulate actual sensors. An SGI based Real-time IR/EO Scene Simulator (RISS) system was developed to utilize the Onyx2's fast multiprocessing hardware to perform real-time IR/EO scene radiance calculations. During real-time scene simulation, the multiprocessors are used to update polygon vertex locations and compute radiometrically accurate floating point radiance values. The output of this process can be utilized to drive a variety of scene rendering engines. Recent advancements in COTS graphics systems, such as the Silicon Graphics InfiniteRealityR make a total COTS solution possible for some classes of sensors. This paper will discuss the critical technologies that apply to infrared scene generation and hardware-in-the-loop testing using SGI compatible hardware. Specifically, the application of RISS high-fidelity real-time radiance algorithms on the SGI Onyx2's multiprocessing hardware will be discussed. Also, issues relating to external real-time control of multiple synchronized scene generation channels will be addressed.

Spectral Analysis of the Primary Flight Focal Plane Arrays for the Thermal Infrared Sensor

NASA Technical Reports Server (NTRS)

Montanaro, Matthew; Reuter, Dennis C.; Markham, Brian L.; Thome, Kurtis J.; Lunsford, Allen W.; Jhabvala, Murzy D.; Rohrbach, Scott O.; Gerace, Aaron D.

2011-01-01

Thermal Infrared Sensor (TIRS) is a (1) New longwave infrared (10 - 12 micron) sensor for the Landsat Data Continuity Mission, (2) 185 km ground swath; 100 meter pixel size on ground, (3) Pushbroom sensor configuration. Issue of Calibration are: (1) Single detector -- only one calibration, (2) Multiple detectors - unique calibration for each detector -- leads to pixel-to-pixel artifacts. Objectives are: (1) Predict extent of residual striping when viewing a uniform blackbody target through various atmospheres, (2) Determine how different spectral shapes affect the derived surface temperature in a realistic synthetic scene.

ASTER First Views of Red Sea, Ethiopia - Thermal-Infrared TIR Image monochrome

NASA Image and Video Library

2000-03-11

ASTER succeeded in acquiring this image at night, which is something Visible/Near Infrared VNIR) and Shortwave Infrared (SWIR) sensors cannot do. The scene covers the Red Sea coastline to an inland area of Ethiopia. White pixels represent areas with higher temperature material on the surface, while dark pixels indicate lower temperatures. This image shows ASTER's ability as a highly sensitive, temperature-discerning instrument and the first spaceborne TIR multi-band sensor in history. The size of image: 60 km x 60 km approx., ground resolution 90 m x 90 m approximately. http://photojournal.jpl.nasa.gov/catalog/PIA02452

Contrast performance modeling of broadband reflective imaging systems with hypothetical tunable filter fore-optics

NASA Astrophysics Data System (ADS)

Hodgkin, Van A.

2015-05-01

Most mass-produced, commercially available and fielded military reflective imaging systems operate across broad swaths of the visible, near infrared (NIR), and shortwave infrared (SWIR) wavebands without any spectral selectivity within those wavebands. In applications that employ these systems, it is not uncommon to be imaging a scene in which the image contrasts between the objects of interest, i.e., the targets, and the objects of little or no interest, i.e., the backgrounds, are sufficiently low to make target discrimination difficult or uncertain. This can occur even when the spectral distribution of the target and background reflectivity across the given waveband differ significantly from each other, because the fundamental components of broadband image contrast are the spectral integrals of the target and background signatures. Spectral integration by the detectors tends to smooth out any differences. Hyperspectral imaging is one approach to preserving, and thus highlighting, spectral differences across the scene, even when the waveband integrated signatures would be about the same, but it is an expensive, complex, noncompact, and untimely solution. This paper documents a study of how the capability to selectively customize the spectral width and center wavelength with a hypothetical tunable fore-optic filter would allow a broadband reflective imaging sensor to optimize image contrast as a function of scene content and ambient illumination.

The visible, near-infrared and short wave infrared channels of the EarthCARE multi-spectral imager

NASA Astrophysics Data System (ADS)

Doornink, J.; de Goeij, B.; Marinescu, O.; Meijer, E.; Vink, R.; van Werkhoven, W.; van't Hof, A.

2017-11-01

The EarthCARE satellite mission objective is the observation of clouds and aerosols from low Earth orbit. The payload will include active remote sensing instruments being the W-band Cloud Profiling Radar (CPR) and the ATLID LIDAR. These are supported by the passive instruments Broadband Radiometer (BBR) and the Multispectral Imager (MSI) providing the radiometric and spatial context of the ground scene being probed. The MSI will form Earth images over a swath width of 150 km; it will image the Earth atmosphere in 7 spectral bands. The MSI instrument consists of two parts: the Visible, Near infrared and Short wave infrared (VNS) unit, and the Thermal InfraRed (TIR) unit. Subject of this paper is the VNS unit. In the VNS optical unit, the ground scene is imaged in four spectral bands onto four linear detectors via separate optical channels. Driving requirements for the VNS instrument performance are the spectral sensitivity including out-of-band rejection, the MTF, co-registration and the inter-channel radiometric accuracy. The radiometric accuracy performance of the VNS is supported by in-orbit calibration, in which direct solar radiation is fed into the instrument via a set of quasi volume diffusers. The compact optical concept with challenging stability requirements together with the strict thermal constraints have led to a sophisticated opto-mechanical design. This paper, being the second of a sequence of two on the Multispectral Imager describes the VNS instrument concept chosen to fulfil the performance requirements within the resource and accommodation constraints.

Simultaneous digital super-resolution and nonuniformity correction for infrared imaging systems.

PubMed

Meza, Pablo; Machuca, Guillermo; Torres, Sergio; Martin, Cesar San; Vera, Esteban

2015-07-20

In this article, we present a novel algorithm to achieve simultaneous digital super-resolution and nonuniformity correction from a sequence of infrared images. We propose to use spatial regularization terms that exploit nonlocal means and the absence of spatial correlation between the scene and the nonuniformity noise sources. We derive an iterative optimization algorithm based on a gradient descent minimization strategy. Results from infrared image sequences corrupted with simulated and real fixed-pattern noise show a competitive performance compared with state-of-the-art methods. A qualitative analysis on the experimental results obtained with images from a variety of infrared cameras indicates that the proposed method provides super-resolution images with significantly less fixed-pattern noise.

Tampa Bay, St. Petersburg, Florida, USA

NASA Technical Reports Server (NTRS)

1992-01-01

This photo of the Tampa Bay, St. Petersburg, Florida (28.0N, 82.5W) is one of a pair (see STS049-97-020) to compare the differences between color film and color infrared film. In the color image above, the scene appears as it would to the human eye. The city of St. Petersburg can be seen even though there is atmospheric haze obscuring the image. Color infrared film filters out the haze and portrays vegetation as shades of red or pink.

MONET: multidimensional radiative cloud scene model

NASA Astrophysics Data System (ADS)

Chervet, Patrick

1999-12-01

All cloud fields exhibit variable structures (bulge) and heterogeneities in water distributions. With the development of multidimensional radiative models by the atmospheric community, it is now possible to describe horizontal heterogeneities of the cloud medium, to study these influences on radiative quantities. We have developed a complete radiative cloud scene generator, called MONET (French acronym for: MOdelisation des Nuages En Tridim.) to compute radiative cloud scene from visible to infrared wavelengths for various viewing and solar conditions, different spatial scales, and various locations on the Earth. MONET is composed of two parts: a cloud medium generator (CSSM -- Cloud Scene Simulation Model) developed by the Air Force Research Laboratory, and a multidimensional radiative code (SHDOM -- Spherical Harmonic Discrete Ordinate Method) developed at the University of Colorado by Evans. MONET computes images for several scenario defined by user inputs: date, location, viewing angles, wavelength, spatial resolution, meteorological conditions (atmospheric profiles, cloud types)... For the same cloud scene, we can output different viewing conditions, or/and various wavelengths. Shadowing effects on clouds or grounds are taken into account. This code is useful to study heterogeneity effects on satellite data for various cloud types and spatial resolutions, and to determine specifications of new imaging sensor.

Cross-sensor comparisons between Landsat 5 TM and IRS-P6 AWiFS and disturbance detection using integrated Landsat and AWiFS time-series images

USGS Publications Warehouse

Chen, Xuexia; Vogelmann, James E.; Chander, Gyanesh; Ji, Lei; Tolk, Brian; Huang, Chengquan; Rollins, Matthew

2013-01-01

Routine acquisition of Landsat 5 Thematic Mapper (TM) data was discontinued recently and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) has an ongoing problem with the scan line corrector (SLC), thereby creating spatial gaps when covering images obtained during the process. Since temporal and spatial discontinuities of Landsat data are now imminent, it is therefore important to investigate other potential satellite data that can be used to replace Landsat data. We thus cross-compared two near-simultaneous images obtained from Landsat 5 TM and the Indian Remote Sensing (IRS)-P6 Advanced Wide Field Sensor (AWiFS), both captured on 29 May 2007 over Los Angeles, CA. TM and AWiFS reflectances were compared for the green, red, near-infrared (NIR), and shortwave infrared (SWIR) bands, as well as the normalized difference vegetation index (NDVI) based on manually selected polygons in homogeneous areas. All R2 values of linear regressions were found to be higher than 0.99. The temporally invariant cluster (TIC) method was used to calculate the NDVI correlation between the TM and AWiFS images. The NDVI regression line derived from selected polygons passed through several invariant cluster centres of the TIC density maps and demonstrated that both the scene-dependent polygon regression method and TIC method can generate accurate radiometric normalization. A scene-independent normalization method was also used to normalize the AWiFS data. Image agreement assessment demonstrated that the scene-dependent normalization using homogeneous polygons provided slightly higher accuracy values than those obtained by the scene-independent method. Finally, the non-normalized and relatively normalized ‘Landsat-like’ AWiFS 2007 images were integrated into 1984 to 2010 Landsat time-series stacks (LTSS) for disturbance detection using the Vegetation Change Tracker (VCT) model. Both scene-dependent and scene-independent normalized AWiFS data sets could generate disturbance maps similar to what were generated using the LTSS data set, and their kappa coefficients were higher than 0.97. These results indicate that AWiFS can be used instead of Landsat data to detect multitemporal disturbance in the event of Landsat data discontinuity.

Tampa Bay, St. Petersburg, Florida, USA

NASA Technical Reports Server (NTRS)

1992-01-01

This photo of the Tampa Bay, St. Petersburg, Florida (28.0N, 82.5W) is one of a pair (see STS049-92-017) to compare the differences between color film and color infrared film. In the color image above, the scene appears as it would to the human eye. The city of St. Petersburg can be seen even though there is atmospheric haze obscuring the image. Color infrared film filters out the haze and portrays vegetation as shades of red or pink.

Tachistoscopic exposure and masking of real three-dimensional scenes

PubMed Central

Pothier, Stephen; Philbeck, John; Chichka, David; Gajewski, Daniel A.

2010-01-01

Although there are many well-known forms of visual cues specifying absolute and relative distance, little is known about how visual space perception develops at small temporal scales. How much time does the visual system require to extract the information in the various absolute and relative distance cues? In this article, we describe a system that may be used to address this issue by presenting brief exposures of real, three-dimensional scenes, followed by a masking stimulus. The system is composed of an electronic shutter (a liquid crystal smart window) for exposing the stimulus scene, and a liquid crystal projector coupled with an electromechanical shutter for presenting the masking stimulus. This system can be used in both full- and reduced-cue viewing conditions, under monocular and binocular viewing, and at distances limited only by the testing space. We describe a configuration that may be used for studying the microgenesis of visual space perception in the context of visually directed walking. PMID:19182129

Toward the light field display: autostereoscopic rendering via a cluster of projectors.

PubMed

Yang, Ruigang; Huang, Xinyu; Li, Sifang; Jaynes, Christopher

2008-01-01

Ultimately, a display device should be capable of reproducing the visual effects observed in reality. In this paper we introduce an autostereoscopic display that uses a scalable array of digital light projectors and a projection screen augmented with microlenses to simulate a light field for a given three-dimensional scene. Physical objects emit or reflect light in all directions to create a light field that can be approximated by the light field display. The display can simultaneously provide many viewers from different viewpoints a stereoscopic effect without head tracking or special viewing glasses. This work focuses on two important technical problems related to the light field display; calibration and rendering. We present a solution to automatically calibrate the light field display using a camera and introduce two efficient algorithms to render the special multi-view images by exploiting their spatial coherence. The effectiveness of our approach is demonstrated with a four-projector prototype that can display dynamic imagery with full parallax.

Distributed rendering for multiview parallax displays

NASA Astrophysics Data System (ADS)

Annen, T.; Matusik, W.; Pfister, H.; Seidel, H.-P.; Zwicker, M.

2006-02-01

3D display technology holds great promise for the future of television, virtual reality, entertainment, and visualization. Multiview parallax displays deliver stereoscopic views without glasses to arbitrary positions within the viewing zone. These systems must include a high-performance and scalable 3D rendering subsystem in order to generate multiple views at real-time frame rates. This paper describes a distributed rendering system for large-scale multiview parallax displays built with a network of PCs, commodity graphics accelerators, multiple projectors, and multiview screens. The main challenge is to render various perspective views of the scene and assign rendering tasks effectively. In this paper we investigate two different approaches: Optical multiplexing for lenticular screens and software multiplexing for parallax-barrier displays. We describe the construction of large-scale multi-projector 3D display systems using lenticular and parallax-barrier technology. We have developed different distributed rendering algorithms using the Chromium stream-processing framework and evaluate the trade-offs and performance bottlenecks. Our results show that Chromium is well suited for interactive rendering on multiview parallax displays.

A portable low-cost 3D point cloud acquiring method based on structure light

NASA Astrophysics Data System (ADS)

Gui, Li; Zheng, Shunyi; Huang, Xia; Zhao, Like; Ma, Hao; Ge, Chao; Tang, Qiuxia

2018-03-01

A fast and low-cost method of acquiring 3D point cloud data is proposed in this paper, which can solve the problems of lack of texture information and low efficiency of acquiring point cloud data with only one pair of cheap cameras and projector. Firstly, we put forward a scene adaptive design method of random encoding pattern, that is, a coding pattern is projected onto the target surface in order to form texture information, which is favorable for image matching. Subsequently, we design an efficient dense matching algorithm that fits the projected texture. After the optimization of global algorithm and multi-kernel parallel development with the fusion of hardware and software, a fast acquisition system of point-cloud data is accomplished. Through the evaluation of point cloud accuracy, the results show that point cloud acquired by the method proposed in this paper has higher precision. What`s more, the scanning speed meets the demand of dynamic occasion and has better practical application value.

Aberration analysis of the putative projector for Lorenzo Lotto's Husband and wife: image analysis through computer ray-tracing

NASA Astrophysics Data System (ADS)

Robinson, Dirk; Stork, David G.

2008-02-01

A recent theory claims that the late-Italian Renaissance painter Lorenzo Lotto secretly built a concave-mirror projector to project an image of a carpet onto his canvas and trace it during the execution of Husband and wife (c. 1543). Key evidence adduced to support this claim includes "perspective anomalies" and changes in "magnification" that the theory's proponents ascribe to Lotto refocusing his projector to overcome its limitations in depth of field. We find, though, that there are important geometrical constraints upon such a putative optical projector not incorporated into the proponents' analyses, and that when properly included, the argument for the use of optics loses its force. We used Zemax optical design software to create a simple model of Lotto's studio and putative projector, and incorporated the optical properties proponents inferred from geometrical properties of the depicted carpet. Our central contribution derives from including the 116-cm-wide canvas screen; we found that this screen forces the incident light to strike the concave mirror at large angles (>= 15°) and that this, in turn, means that the projected image would reveal severe off-axis aberrations, particularly astigmatism. Such aberrations are roughly as severe as the defocus blur claimed to have led Lotto to refocus the projector. In short, we find that the projected images would not have gone in and out of focus in the way claimed by proponents, a result that undercuts their claim that Lotto used a projector for this painting. We speculate on the value of further uses of sophisticated ray-tracing analyses in the study of fine arts.

40. View of dual projector system located in MWOC facility ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

40. View of dual projector system located in MWOC facility in transmitter building no. 102 by Bessler Company. System used to project images in MWOC on backlit screen system with fiber optic electro/mechanical system linked to computer output to indicate information on screen linked with display from projector system. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Overhead Projector Demonstrations.

ERIC Educational Resources Information Center

Kolb, Doris, Ed.

1987-01-01

Describes several chemistry demonstrations that use an overhead projector. Some of the demonstrations deal with electrochemistry, and another deals with the reactions of nonvolatile immiscible liquid in water. (TW)

A computer vision system for the recognition of trees in aerial photographs

NASA Technical Reports Server (NTRS)

Pinz, Axel J.

1991-01-01

Increasing problems of forest damage in Central Europe set the demand for an appropriate forest damage assessment tool. The Vision Expert System (VES) is presented which is capable of finding trees in color infrared aerial photographs. Concept and architecture of VES are discussed briefly. The system is applied to a multisource test data set. The processing of this multisource data set leads to a multiple interpretation result for one scene. An integration of these results will provide a better scene description by the vision system. This is achieved by an implementation of Steven's correlation algorithm.

Overhead Projector Demonstrations.

ERIC Educational Resources Information Center

Kolb, Doris, Ed.

1989-01-01

Included are demonstrations using the overhead projector to show change in optical rotation with wavelength and aromatic pi cloud availability, and formation of colored charge-transfer complexes. Instructional techniques unique to these topics are discussed. (CW)

Radiometric consistency assessment of hyperspectral infrared sounders

NASA Astrophysics Data System (ADS)

Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

2015-11-01

The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark data sets for both intercalibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and MetOp-B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through simultaneous nadir overpass (SNO) observations in 2013, to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the long-wave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both polar and tropical SNOs. The combined global SNO data sets indicate that the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 spectral regions and they range from 0.15 to 0.21 K in the remaining four spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

Overhead Projector Demonstrations.

ERIC Educational Resources Information Center

Kolb, Doris, Ed.

1989-01-01

Described are demonstrations of the optical activity of two sugar solutions, and the effects of various substituents on acid strength using an overhead projector. Materials and procedures for each demonstration are discussed. (CW)

Shutterless non-uniformity correction for the long-term stability of an uncooled long-wave infrared camera

NASA Astrophysics Data System (ADS)

Liu, Chengwei; Sui, Xiubao; Gu, Guohua; Chen, Qian

2018-02-01

For the uncooled long-wave infrared (LWIR) camera, the infrared (IR) irradiation the focal plane array (FPA) receives is a crucial factor that affects the image quality. Ambient temperature fluctuation as well as system power consumption can result in changes of FPA temperature and radiation characteristics inside the IR camera; these will further degrade the imaging performance. In this paper, we present a novel shutterless non-uniformity correction method to compensate for non-uniformity derived from the variation of ambient temperature. Our method combines a calibration-based method and the properties of a scene-based method to obtain correction parameters at different ambient temperature conditions, so that the IR camera performance can be less influenced by ambient temperature fluctuation or system power consumption. The calibration process is carried out in a temperature chamber with slowly changing ambient temperature and a black body as uniform radiation source. Enough uniform images are captured and the gain coefficients are calculated during this period. Then in practical application, the offset parameters are calculated via the least squares method based on the gain coefficients, the captured uniform images and the actual scene. Thus we can get a corrected output through the gain coefficients and offset parameters. The performance of our proposed method is evaluated on realistic IR images and compared with two existing methods. The images we used in experiments are obtained by a 384× 288 pixels uncooled LWIR camera. Results show that our proposed method can adaptively update correction parameters as the actual target scene changes and is more stable to temperature fluctuation than the other two methods.

A novel design of membrane mirror with small deformation and imaging performance analysis in infrared system

NASA Astrophysics Data System (ADS)

Zhang, Shuqing; Wang, Yongquan; Zhi, Xiyang

2017-05-01

A method of diminishing the shape error of membrane mirror is proposed in this paper. The inner inflating pressure is considerably decreased by adopting the pre-shaped membrane. Small deformation of the membrane mirror with greatly reduced shape error is sequentially achieved. Primarily a finite element model of the above pre-shaped membrane is built on the basis of its mechanical properties. Then accurate shape data under different pressures can be acquired by iteratively calculating the node displacements of the model. Shape data are applicable to build up deformed reflecting surfaces for the simulative analysis in ZEMAX. Finally, ground-based imaging experiments of 4-bar targets and nature scene are conducted. Experiment results indicate that the MTF of the infrared system can reach to 0.3 at a high spatial resolution of 10l p/mm, and texture details of the nature scene are well-presented. The method can provide theoretical basis and technical support for the applications in lightweight optical components with ultra-large apertures.

Use of an Infrared Thermometer with Laser Targeting in Morphological Scene Change Detection for Fire Detection

NASA Astrophysics Data System (ADS)

Tickle, Andrew J.; Singh, Harjap; Grindley, Josef E.

2013-06-01

Morphological Scene Change Detection (MSCD) is a process typically tasked at detecting relevant changes in a guarded environment for security applications. This can be implemented on a Field Programmable Gate Array (FPGA) by a combination of binary differences based around exclusive-OR (XOR) gates, mathematical morphology and a crucial threshold setting. This is a robust technique and can be applied many areas from leak detection to movement tracking, and further augmented to perform additional functions such as watermarking and facial detection. Fire is a severe problem, and in areas where traditional fire alarm systems are not installed or feasible, it may not be detected until it is too late. Shown here is a way of adapting the traditional Morphological Scene Change Detector (MSCD) with a temperature sensor so if both the temperature sensor and scene change detector are triggered, there is a high likelihood of fire present. Such a system would allow integration into autonomous mobile robots so that not only security patrols could be undertaken, but also fire detection.

Research of infrared laser based pavement imaging and crack detection

NASA Astrophysics Data System (ADS)

Hong, Hanyu; Wang, Shu; Zhang, Xiuhua; Jing, Genqiang

2013-08-01

Road crack detection is seriously affected by many factors in actual applications, such as some shadows, road signs, oil stains, high frequency noise and so on. Due to these factors, the current crack detection methods can not distinguish the cracks in complex scenes. In order to solve this problem, a novel method based on infrared laser pavement imaging is proposed. Firstly, single sensor laser pavement imaging system is adopted to obtain pavement images, high power laser line projector is well used to resist various shadows. Secondly, the crack extraction algorithm which has merged multiple features intelligently is proposed to extract crack information. In this step, the non-negative feature and contrast feature are used to extract the basic crack information, and circular projection based on linearity feature is applied to enhance the crack area and eliminate noise. A series of experiments have been performed to test the proposed method, which shows that the proposed automatic extraction method is effective and advanced.

Overhead Projector Demonstrations: A Classroom Demonstration of Aliphatic Substitution.

ERIC Educational Resources Information Center

Perina, Ivo; Mihanovic, Branka

1989-01-01

Presents a halogen substitution of an alkane using a compartmentalized Petri dish or Conway dish on an overhead projector. Provides methodology and several modifications for different reactions. Uses hexane, methyl orange, bromine, and silver nitrate. (MVL)

Joint de-blurring and nonuniformity correction method for infrared microscopy imaging

NASA Astrophysics Data System (ADS)

Jara, Anselmo; Torres, Sergio; Machuca, Guillermo; Ramírez, Wagner; Gutiérrez, Pablo A.; Viafora, Laura A.; Godoy, Sebastián E.; Vera, Esteban

2018-05-01

In this work, we present a new technique to simultaneously reduce two major degradation artifacts found in mid-wavelength infrared microscopy imagery, namely the inherent focal-plane array nonuniformity noise and the scene defocus presented due to the point spread function of the infrared microscope. We correct both nuisances using a novel, recursive method that combines the constant range nonuniformity correction algorithm with a frame-by-frame deconvolution approach. The ability of the method to jointly compensate for both nonuniformity noise and blur is demonstrated using two different real mid-wavelength infrared microscopic video sequences, which were captured from two microscopic living organisms using a Janos-Sofradir mid-wavelength infrared microscopy setup. The performance of the proposed method is assessed on real and simulated infrared data by computing the root mean-square error and the roughness-laplacian pattern index, which was specifically developed for the present work.

Robotic vision techniques for space operations

NASA Technical Reports Server (NTRS)

Krishen, Kumar

1994-01-01

Automation and robotics for space applications are being pursued for increased productivity, enhanced reliability, increased flexibility, higher safety, and for the automation of time-consuming tasks and those activities which are beyond the capacity of the crew. One of the key functional elements of an automated robotic system is sensing and perception. As the robotics era dawns in space, vision systems will be required to provide the key sensory data needed for multifaceted intelligent operations. In general, the three-dimensional scene/object description, along with location, orientation, and motion parameters will be needed. In space, the absence of diffused lighting due to a lack of atmosphere gives rise to: (a) high dynamic range (10(exp 8)) of scattered sunlight intensities, resulting in very high contrast between shadowed and specular portions of the scene; (b) intense specular reflections causing target/scene bloom; and (c) loss of portions of the image due to shadowing and presence of stars, Earth, Moon, and other space objects in the scene. In this work, developments for combating the adverse effects described earlier and for enhancing scene definition are discussed. Both active and passive sensors are used. The algorithm for selecting appropriate wavelength, polarization, look angle of vision sensors is based on environmental factors as well as the properties of the target/scene which are to be perceived. The environment is characterized on the basis of sunlight and other illumination incident on the target/scene and the temperature profiles estimated on the basis of the incident illumination. The unknown geometrical and physical parameters are then derived from the fusion of the active and passive microwave, infrared, laser, and optical data.

Centripetal Force on an Overhead Projector.

ERIC Educational Resources Information Center

Rheam, Harry

1995-01-01

Describes two simple demonstrations of an object moving in a straight line tangent to the circle if centripetal force is removed. Demonstrations use a pie plate and petri dish with ball bearings to illustrate the phenomena on an overhead projector. (LZ)

Detection range enhancement using circularly polarized light in scattering environments for infrared wavelengths

DOE PAGES

van der Laan, J. D.; Sandia National Lab.; Scrymgeour, D. A.; ...

2015-03-13

We find for infrared wavelengths there are broad ranges of particle sizes and refractive indices that represent fog and rain where the use of circular polarization can persist to longer ranges than linear polarization. Using polarization tracking Monte Carlo simulations for varying particle size, wavelength, and refractive index, we show that for specific scene parameters circular polarization outperforms linear polarization in maintaining the intended polarization state for large optical depths. This enhancement with circular polarization can be exploited to improve range and target detection in obscurant environments that are important in many critical sensing applications. Specifically, circular polarization persists bettermore » than linear for radiation fog in the short-wave infrared, for advection fog in the short-wave infrared and the long-wave infrared, and large particle sizes of Sahara dust around the 4 micron wavelength.« less

Methods of editing cloud and atmospheric layer affected pixels from satellite data

NASA Technical Reports Server (NTRS)

Nixon, P. R.; Wiegand, C. L.; Richardson, A. J.; Johnson, M. P. (Principal Investigator)

1982-01-01

Subvisible cirrus clouds (SCi) were easily distinguished in mid-infrared (MIR) TIROS-N daytime data from south Texas and northeast Mexico. The MIR (3.55-3.93 micrometer) pixel digital count means of the SCi affected areas were more than 3.5 standard deviations on the cold side of the scene means. (These standard deviations were made free of the effects of unusual instrument error by factoring out the Ch 3 MIR noise on the basis of detailed examination of noisy and noise-free pixels). SCi affected areas in the IR Ch 4 (10.5-11.5 micrometer) appeared cooler than the general scene, but were not as prominent as in Ch 3, being less than 2 standard deviations from the scene mean. Ch 3 and 4 standard deviations and coefficients of variation are not reliable indicators, by themselves, of the presence of SCi because land features can have similar statistical properties.

Thermal-depth matching in dynamic scene based on affine projection and feature registration

NASA Astrophysics Data System (ADS)

Wang, Hongyu; Jia, Tong; Wu, Chengdong; Li, Yongqiang

2018-03-01

This paper aims to study the construction of 3D temperature distribution reconstruction system based on depth and thermal infrared information. Initially, a traditional calibration method cannot be directly used, because the depth and thermal infrared camera is not sensitive to the color calibration board. Therefore, this paper aims to design a depth and thermal infrared camera calibration board to complete the calibration of the depth and thermal infrared camera. Meanwhile a local feature descriptors in thermal and depth images is proposed. The belief propagation matching algorithm is also investigated based on the space affine transformation matching and local feature matching. The 3D temperature distribution model is built based on the matching of 3D point cloud and 2D thermal infrared information. Experimental results show that the method can accurately construct the 3D temperature distribution model, and has strong robustness.

Modern Approaches to the Computation of the Probability of Target Detection in Cluttered Environments

NASA Astrophysics Data System (ADS)

Meitzler, Thomas J.

The field of computer vision interacts with fields such as psychology, vision research, machine vision, psychophysics, mathematics, physics, and computer science. The focus of this thesis is new algorithms and methods for the computation of the probability of detection (Pd) of a target in a cluttered scene. The scene can be either a natural visual scene such as one sees with the naked eye (visual), or, a scene displayed on a monitor with the help of infrared sensors. The relative clutter and the temperature difference between the target and background (DeltaT) are defined and then used to calculate a relative signal -to-clutter ratio (SCR) from which the Pd is calculated for a target in a cluttered scene. It is shown how this definition can include many previous definitions of clutter and (DeltaT). Next, fuzzy and neural -fuzzy techniques are used to calculate the Pd and it is shown how these methods can give results that have a good correlation with experiment. The experimental design for actually measuring the Pd of a target by observers is described. Finally, wavelets are applied to the calculation of clutter and it is shown how this new definition of clutter based on wavelets can be used to compute the Pd of a target.

Active modulation of laser coded systems using near infrared video projection system based on digital micromirror device (DMD)

NASA Astrophysics Data System (ADS)

Khalifa, Aly A.; Aly, Hussein A.; El-Sherif, Ashraf F.

2016-02-01

Near infrared (NIR) dynamic scene projection systems are used to perform hardware in-the-loop (HWIL) testing of a unit under test operating in the NIR band. The common and complex requirement of a class of these units is a dynamic scene that is spatio-temporal variant. In this paper we apply and investigate active external modulation of NIR laser in different ranges of temporal frequencies. We use digital micromirror devices (DMDs) integrated as the core of a NIR projection system to generate these dynamic scenes. We deploy the spatial pattern to the DMD controller to simultaneously yield the required amplitude by pulse width modulation (PWM) of the mirror elements as well as the spatio-temporal pattern. Desired modulation and coding of high stable, high power visible (Red laser at 640 nm) and NIR (Diode laser at 976 nm) using the combination of different optical masks based on DMD were achieved. These spatial versatile active coding strategies for both low and high frequencies in the range of kHz for irradiance of different targets were generated by our system and recorded using VIS-NIR fast cameras. The temporally-modulated laser pulse traces were measured using array of fast response photodetectors. Finally using a high resolution spectrometer, we evaluated the NIR dynamic scene projection system response in terms of preserving the wavelength and band spread of the NIR source after projection.

Dynamic thermal signature prediction for real-time scene generation

NASA Astrophysics Data System (ADS)

Christie, Chad L.; Gouthas, Efthimios (Themie); Williams, Owen M.; Swierkowski, Leszek

2013-05-01

At DSTO, a real-time scene generation framework, VIRSuite, has been developed in recent years, within which trials data are predominantly used for modelling the radiometric properties of the simulated objects. Since in many cases the data are insufficient, a physics-based simulator capable of predicting the infrared signatures of objects and their backgrounds has been developed as a new VIRSuite module. It includes transient heat conduction within the materials, and boundary conditions that take into account the heat fluxes due to solar radiation, wind convection and radiative transfer. In this paper, an overview is presented, covering both the steady-state and transient performance.

Modular design of the LED vehicle projector headlamp system.

PubMed

Hsieh, Chi-Chang; Li, Yan-Huei; Hung, Chih-Ching

2013-07-20

A well designed headlamp for a vehicle lighting system is very important as it provides drivers with safe and comfortable driving conditions at night or in dark places. With the advances of the semiconductor technology, the LED has become the fourth generation lighting source in the auto industry. In this study, we will propose a LED vehicle projector headlamp system. This headlamp system contains several LED headlamp modules, and every module of it includes four components: focused LEDs, asymmetric metal-based plates, freeform surfaces, and condenser lenses. By optimizing the number of LED headlamp modules, the proposed LED vehicle projector headlamp system has only five LED headlamp modules. It not only provides the low-beam cutoff without a shield, but also meets the requirements of the ECE R112 regulation. Finally, a prototype of the LED vehicle projector headlamp system was assembled and fabricated to create the correct light pattern.

Multi-projector auto-calibration and placement optimization for non-planar surfaces

NASA Astrophysics Data System (ADS)

Li, Dong; Xie, Jinghui; Zhao, Lu; Zhou, Lijing; Weng, Dongdong

2015-10-01

Non-planar projection has been widely applied in virtual reality and digital entertainment and exhibitions because of its flexible layout and immersive display effects. Compared with planar projection, a non-planar projection is more difficult to achieve because projector calibration and image distortion correction are difficult processes. This paper uses a cylindrical screen as an example to present a new method for automatically calibrating a multi-projector system in a non-planar environment without using 3D reconstruction. This method corrects the geometric calibration error caused by the screen's manufactured imperfections, such as an undulating surface or a slant in the vertical plane. In addition, based on actual projection demand, this paper presents the overall performance evaluation criteria for the multi-projector system. According to these criteria, we determined the optimal placement for the projectors. This method also extends to surfaces that can be parameterized, such as spheres, ellipsoids, and paraboloids, and demonstrates a broad applicability.

High resolution satellite observations of mesoscale oceanography in the Tasman Sea, 1978 - 1979

NASA Technical Reports Server (NTRS)

Nilsson, C. S.; Andrews, J. C.; Hornibrook, M.; Latham, A. R.; Speechley, G. C.; Scully-Power, P. (Principal Investigator)

1982-01-01

Of the Nearly 1000 standard infrared photographic images received, 273 images were on computer compatible tape. It proved necessary to digitally enhance the scene contrast to cover only a select few degrees K over the photographic grey scale appropriate to the scene-specific range of sea surface temperature (SST). Some 178 images were so enhanced. Comparison with sea truth show that SST, as seen by satellite, provides a good guide to the ocean currents and eddies off East Australia, both in summer and winter. This is in contrast, particularly in summer, to SST mapped by surface survey, which usually lacks the necessary spatial resolution.

Real-time interactive projection system based on infrared structured-light method

NASA Astrophysics Data System (ADS)

Qiao, Xiaorui; Zhou, Qian; Ni, Kai; He, Liang; Wu, Guanhao; Mao, Leshan; Cheng, Xuemin; Ma, Jianshe

2012-11-01

Interactive technologies have been greatly developed in recent years, especially in projection field. However, at present, most interactive projection systems are based on special designed interactive pens or whiteboards, which is inconvenient and limits the improvement of user experience. In this paper, we introduced our recent progress on theoretically modeling a real-time interactive projection system. The system permits the user to easily operate or draw on the projection screen directly by fingers without any other auxiliary equipment. The projector projects infrared striping patterns onto the screen and the CCD captures the deformational image. We resolve the finger's position and track its movement by processing the deformational image in real-time. A new way to determine whether the finger touches the screen is proposed. The first deformational fringe on the fingertip and the first fringe at the finger shadow are the same one. The correspondence is obtained, so the location parameters can be decided by triangulation. The simulation results are given, and errors are analyzed.

Overhead Projector Demonstrations: Tilted TOPS: Inclined Plane Projection.

ERIC Educational Resources Information Center

Alyea, Hubert N.

1989-01-01

The construction and uses of a device to facilitate the use of an overhead projector to show chemical reactions is presented. Materials and instructions for construction as well as reactor vessels are discussed. (CW)

Projector Center: Using an Overhead Projector to Initiate Discussion of Life and Non-Life.

ERIC Educational Resources Information Center

Barman, Charles R.

1982-01-01

Describes a demonstration and role-playing activity focusing on differences between living/dead, definitions of living/dead, and situations in which active euthanasia could be morally right. (Author/JN)

The fermionic projector in a time-dependent external potential: Mass oscillation property and Hadamard states

NASA Astrophysics Data System (ADS)

Finster, Felix; Murro, Simone; Röken, Christian

2016-07-01

We give a non-perturbative construction of the fermionic projector in Minkowski space coupled to a time-dependent external potential which is smooth and decays faster than quadratically for large times. The weak and strong mass oscillation properties are proven. We show that the integral kernel of the fermionic projector is of the Hadamard form, provided that the time integral of the spatial sup-norm of the potential satisfies a suitable bound. This gives rise to an algebraic quantum field theory of Dirac fields in an external potential with a distinguished pure quasi-free Hadamard state.

Predicting top-of-atmosphere radiance for arbitrary viewing geometries from the visible to thermal infrared: generalization to arbitrary average scene temperatures

NASA Astrophysics Data System (ADS)

Florio, Christopher J.; Cota, Steve A.; Gaffney, Stephanie K.

2010-08-01

In a companion paper presented at this conference we described how The Aerospace Corporation's Parameterized Image Chain Analysis & Simulation SOftware (PICASSO) may be used in conjunction with a limited number of runs of AFRL's MODTRAN4 radiative transfer code, to quickly predict the top-of-atmosphere (TOA) radiance received in the visible through midwave IR (MWIR) by an earth viewing sensor, for any arbitrary combination of solar and sensor elevation angles. The method is particularly useful for large-scale scene simulations where each pixel could have a unique value of reflectance/emissivity and temperature, making the run-time required for direct prediction via MODTRAN4 prohibitive. In order to be self-consistent, the method described requires an atmospheric model (defined, at a minimum, as a set of vertical temperature, pressure and water vapor profiles) that is consistent with the average scene temperature. MODTRAN4 provides only six model atmospheres, ranging from sub-arctic winter to tropical conditions - too few to cover with sufficient temperature resolution the full range of average scene temperatures that might be of interest. Model atmospheres consistent with intermediate temperature values can be difficult to come by, and in any event, their use would be too cumbersome for use in trade studies involving a large number of average scene temperatures. In this paper we describe and assess a method for predicting TOA radiance for any arbitrary average scene temperature, starting from only a limited number of model atmospheres.

On the regularized fermionic projector of the vacuum

NASA Astrophysics Data System (ADS)

Finster, Felix

2008-03-01

We construct families of fermionic projectors with spherically symmetric regularization, which satisfy the condition of a distributional MP-product. The method is to analyze regularization tails with a power law or logarithmic scaling in composite expressions in the fermionic projector. The resulting regularizations break the Lorentz symmetry and give rise to a multilayer structure of the fermionic projector near the light cone. Furthermore, we construct regularizations which go beyond the distributional MP-product in that they yield additional distributional contributions supported at the origin. The remaining freedom for the regularization parameters and the consequences for the normalization of the fermionic states are discussed.

Spectroscopy on the Overhead Projector.

ERIC Educational Resources Information Center

Solomon, Sally; And Others

1994-01-01

Any overhead projector easily can be converted into a simple spectrometer by placing a piece of diffraction grating over the projecting lens. A detailed description of the apparatus and suggested spectroscopy experiments are included. Demonstrations can utilize solutions of cobalt chloride, potassium permanganate, potassium dichromate, or…

The causal perturbation expansion revisited: Rescaling the interacting Dirac sea

NASA Astrophysics Data System (ADS)

Finster, Felix; Grotz, Andreas

2010-07-01

The causal perturbation expansion defines the Dirac sea in the presence of a time-dependent external field. It yields an operator whose image generalizes the vacuum solutions of negative energy and thus gives a canonical splitting of the solution space into two subspaces. After giving a self-contained introduction to the ideas and techniques, we show that this operator is, in general, not idempotent. We modify the standard construction by a rescaling procedure giving a projector on the generalized negative-energy subspace. The resulting rescaled causal perturbation expansion uniquely defines the fermionic projector in terms of a series of distributional solutions of the Dirac equation. The technical core of the paper is to work out the combinatorics of the expansion in detail. It is also shown that the fermionic projector with interaction can be obtained from the free projector by a unitary transformation. We finally analyze the consequences of the rescaling procedure on the light-cone expansion.

Efficiency enhancement of liquid crystal projection displays using light recycle technology

NASA Technical Reports Server (NTRS)

Wang, Y.

2002-01-01

A new technology developed at JPL using low absorption color filters with polarization and color recycle system, is able to enhance efficiency of a single panel liquid crytal display (LCD) projector to the same efficiency of a 3 panel LCD projector.

A Forensic Experiment: The Case of the Crime at the Cinema

ERIC Educational Resources Information Center

Valente Nabais, J. M.; Costa, Sara D.

2017-01-01

This paper reports an experimental activity where students have to carefully analyze the evidence collected at the crime scene, namely fibers and lipstick traces. The fibers are analyzed by infrared spectroscopy, solubility tests, and optical microscopy, while in turn the lipstick traces are investigated by thin layer chromatography. Students also…

High-Resolution Surface Reconstruction from Imagery for Close Range Cultural Heritage Applications

NASA Astrophysics Data System (ADS)

Wenzel, K.; Abdel-Wahab, M.; Cefalu, A.; Fritsch, D.

2012-07-01

The recording of high resolution point clouds with sub-mm resolution is a demanding and cost intensive task, especially with current equipment like handheld laser scanners. We present an image based approached, where techniques of image matching and dense surface reconstruction are combined with a compact and affordable rig of off-the-shelf industry cameras. Such cameras provide high spatial resolution with low radiometric noise, which enables a one-shot solution and thus an efficient data acquisition while satisfying high accuracy requirements. However, the largest drawback of image based solutions is often the acquisition of surfaces with low texture where the image matching process might fail. Thus, an additional structured light projector is employed, represented here by the pseudo-random pattern projector of the Microsoft Kinect. Its strong infrared-laser projects speckles of different sizes. By using dense image matching techniques on the acquired images, a 3D point can be derived for almost each pixel. The use of multiple cameras enables the acquisition of a high resolution point cloud with high accuracy for each shot. For the proposed system up to 3.5 Mio. 3D points with sub-mm accuracy can be derived per shot. The registration of multiple shots is performed by Structure and Motion reconstruction techniques, where feature points are used to derive the camera positions and rotations automatically without initial information.

A simple and high-resolution stereolithography-based 3D bioprinting system using visible light crosslinkable bioinks.

PubMed

Wang, Zongjie; Abdulla, Raafa; Parker, Benjamin; Samanipour, Roya; Ghosh, Sanjoy; Kim, Keekyoung

2015-12-22

Bioprinting is a rapidly developing technique for biofabrication. Because of its high resolution and the ability to print living cells, bioprinting has been widely used in artificial tissue and organ generation as well as microscale living cell deposition. In this paper, we present a low-cost stereolithography-based bioprinting system that uses visible light crosslinkable bioinks. This low-cost stereolithography system was built around a commercial projector with a simple water filter to prevent harmful infrared radiation from the projector. The visible light crosslinking was achieved by using a mixture of polyethylene glycol diacrylate (PEGDA) and gelatin methacrylate (GelMA) hydrogel with eosin Y based photoinitiator. Three different concentrations of hydrogel mixtures (10% PEG, 5% PEG + 5% GelMA, and 2.5% PEG + 7.5% GelMA, all w/v) were studied with the presented systems. The mechanical properties and microstructure of the developed bioink were measured and discussed in detail. Several cell-free hydrogel patterns were generated to demonstrate the resolution of the solution. Experimental results with NIH 3T3 fibroblast cells show that this system can produce a highly vertical 3D structure with 50 μm resolution and 85% cell viability for at least five days. The developed system provides a low-cost visible light stereolithography solution and has the potential to be widely used in tissue engineering and bioengineering for microscale cell patterning.

Infrared Cephalic-Vein to Assist Blood Extraction Tasks: Automatic Projection and Recognition

NASA Astrophysics Data System (ADS)

Lagüela, S.; Gesto, M.; Riveiro, B.; González-Aguilera, D.

2017-05-01

Thermal infrared band is not commonly used in photogrammetric and computer vision algorithms, mainly due to the low spatial resolution of this type of imagery. However, this band captures sub-superficial information, increasing the capabilities of visible bands regarding applications. This fact is especially important in biomedicine and biometrics, allowing the geometric characterization of interior organs and pathologies with photogrammetric principles, as well as the automatic identification and labelling using computer vision algorithms. This paper presents advances of close-range photogrammetry and computer vision applied to thermal infrared imagery, with the final application of Augmented Reality in order to widen its application in the biomedical field. In this case, the thermal infrared image of the arm is acquired and simultaneously projected on the arm, together with the identification label of the cephalic-vein. This way, blood analysts are assisted in finding the vein for blood extraction, especially in those cases where the identification by the human eye is a complex task. Vein recognition is performed based on the Gaussian temperature distribution in the area of the vein, while the calibration between projector and thermographic camera is developed through feature extraction and pattern recognition. The method is validated through its application to a set of volunteers, with different ages and genres, in such way that different conditions of body temperature and vein depth are covered for the applicability and reproducibility of the method.

Computational imaging with a single-pixel detector and a consumer video projector

NASA Astrophysics Data System (ADS)

Sych, D.; Aksenov, M.

2018-02-01

Single-pixel imaging is a novel rapidly developing imaging technique that employs spatially structured illumination and a single-pixel detector. In this work, we experimentally demonstrate a fully operating modular single-pixel imaging system. Light patterns in our setup are created with help of a computer-controlled digital micromirror device from a consumer video projector. We investigate how different working modes and settings of the projector affect the quality of reconstructed images. We develop several image reconstruction algorithms and compare their performance for real imaging. Also, we discuss the potential use of the single-pixel imaging system for quantum applications.

Viewing Vertical Objects with an Overhead Projector.

ERIC Educational Resources Information Center

Wild, R. L.

1988-01-01

Discusses the use of an overhead projector for the deflection of a vertical image to a screen. Describes three demonstrations: magnetizing of a steel ball bearing and paper clip; convection currents of a hot liquid within a cold liquid; and oscillation of concentrated salt solution into fresh water. (YP)

Considerations in Using Computer for Presentation.

ERIC Educational Resources Information Center

Lee, Shih-chung

1997-01-01

Addresses issues to consider in conducting computer presentations. Discusses presentation devices--television, multiscan capable monitor, LCD (liquid crystal display) panel with overhead projector, and video/RGB (red, green, blue) projector; lighting; audience size; and types of presentations--fast/short time multimedia presentations, oral and…

Relative spectral response corrected calibration inter-comparison of S-NPP VIIRS and Aqua MODIS thermal emissive bands

NASA Astrophysics Data System (ADS)

Efremova, Boryana; Wu, Aisheng; Xiong, Xiaoxiong

2014-09-01

The S-NPP Visible Infrared Imaging Radiometer Suite (VIIRS) instrument is built with strong heritage from EOS MODIS, and has very similar thermal emissive bands (TEB) calibration algorithm and on-board calibrating source - a V-grooved blackbody. The calibration of the two instruments can be assessed by comparing the brightness temperatures retrieved from VIIRS and Aqua MODIS simultaneous nadir observations (SNO) from their spectrally matched TEB. However, even though the VIIRS and MODIS bands are similar there are still relative spectral response (RSR) differences and thus some differences in the retrieved brightness temperatures are expected. The differences depend on both the type and the temperature of the observed scene, and contribute to the bias and the scatter of the comparison. In this paper we use S-NPP Cross-track Infrared Sounder (CrIS) data taken simultaneously with the VIIRS data to derive a correction for the slightly different spectral coverage of VIIRS and MODIS TEB bands. An attempt to correct for RSR differences is also made using MODTRAN models, computed with physical parameters appropriate for each scene, and compared to the value derived from actual CrIS spectra. After applying the CrIS-based correction for RSR differences we see an excellent agreement between the VIIRS and Aqua MODIS measurements in the studied band pairs M13-B23, M15-B31, and M16- B32. The agreement is better than the VIIRS uncertainty at cold scenes, and improves with increasing scene temperature up to about 290K.

Scene-based nonuniformity correction technique that exploits knowledge of the focal-plane array readout architecture.

PubMed

Narayanan, Balaji; Hardie, Russell C; Muse, Robert A

2005-06-10

Spatial fixed-pattern noise is a common and major problem in modern infrared imagers owing to the nonuniform response of the photodiodes in the focal plane array of the imaging system. In addition, the nonuniform response of the readout and digitization electronics, which are involved in multiplexing the signals from the photodiodes, causes further nonuniformity. We describe a novel scene based on a nonuniformity correction algorithm that treats the aggregate nonuniformity in separate stages. First, the nonuniformity from the readout amplifiers is corrected by use of knowledge of the readout architecture of the imaging system. Second, the nonuniformity resulting from the individual detectors is corrected with a nonlinear filter-based method. We demonstrate the performance of the proposed algorithm by applying it to simulated imagery and real infrared data. Quantitative results in terms of the mean absolute error and the signal-to-noise ratio are also presented to demonstrate the efficacy of the proposed algorithm. One advantage of the proposed algorithm is that it requires only a few frames to obtain high-quality corrections.

The ship-borne infrared searching and tracking system based on the inertial platform

NASA Astrophysics Data System (ADS)

Li, Yan; Zhang, Haibo

2011-08-01

As a result of the radar system got interferenced or in the state of half silent ,it can cause the guided precision drop badly In the modern electronic warfare, therefore it can lead to the equipment depended on electronic guidance cannot strike the incoming goals exactly. It will need to rely on optoelectronic devices to make up for its shortcomings, but when interference is in the process of radar leading ,especially the electro-optical equipment is influenced by the roll, pitch and yaw rotation ,it can affect the target appear outside of the field of optoelectronic devices for a long time, so the infrared optoelectronic equipment can not exert the superiority, and also it cannot get across weapon-control system "reverse bring" missile against incoming goals. So the conventional ship-borne infrared system unable to track the target of incoming quickly , the ability of optoelectronic rivalry declines heavily.Here we provide a brand new controlling algorithm for the semi-automatic searching and infrared tracking based on inertial navigation platform. Now it is applying well in our XX infrared optoelectronic searching and tracking system. The algorithm is mainly divided into two steps: The artificial mode turns into auto-searching when the deviation of guide exceeds the current scene under the course of leading for radar.When the threshold value of the image picked-up is satisfied by the contrast of the target in the searching scene, the speed computed by using the CA model Least Square Method feeds back to the speed loop. And then combine the infrared information to accomplish the closed-loop control of the infrared optoelectronic system tracking. The algorithm is verified via experiment. Target capturing distance is 22.3 kilometers on the great lead deviation by using the algorithm. But without using the algorithm the capturing distance declines 12 kilometers. The algorithm advances the ability of infrared optoelectronic rivalry and declines the target capturing time by using semi-automatic searching and reliable capturing-tracking, when the lead deviation of the radar is great.

A Simple Polarimeter and Experiments Utilizing an Overhead Projector.

ERIC Educational Resources Information Center

Dorn, H. C.; And Others

1984-01-01

Although polarimeters that illustrate rotation of plane-polarized light by chiral solutions have been previously described, the polarimeter described in this paper has certain advantages when used in conjunction with an overhead projector. Instructions for constructing this polarimeter and its use in demonstrating the optical activity of sugars…

Launcher and Transparent Air Table for Use with Overhead Projector

ERIC Educational Resources Information Center

Carr, H. Y.; and others

1969-01-01

Describes an apparatus designed for quantitative demonstrations of collision experiments. The apparatus consists of a transparent air table and a launching device for projecting two objects simultaneously. It may be used with an overhead projector. The apparatus won third prize in Demonstration Lecture Apparatus in the A.A.P.T. Apparatus…

Creating a Smart Classroom

ERIC Educational Resources Information Center

Domermuth, David

2005-01-01

This article provides a description of an affordable, smart classroom built for the Technology Department at Appalachian State university. The system consists of three basic components: a home theater combo, a tablet PC, and a digital projector, costing a total of $7,300, or $8,800 if a podium, screen, and projector mount are purchased. The…

Infrared hyperspectral imaging for chemical vapour detection

NASA Astrophysics Data System (ADS)

Ruxton, K.; Robertson, G.; Miller, W.; Malcolm, G. P. A.; Maker, G. T.; Howle, C. R.

2012-10-01

Active hyperspectral imaging is a valuable tool in a wide range of applications. One such area is the detection and identification of chemicals, especially toxic chemical warfare agents, through analysis of the resulting absorption spectrum. This work presents a selection of results from a prototype midwave infrared (MWIR) hyperspectral imaging instrument that has successfully been used for compound detection at a range of standoff distances. Active hyperspectral imaging utilises a broadly tunable laser source to illuminate the scene with light at a range of wavelengths. While there are a number of illumination methods, the chosen configuration illuminates the scene by raster scanning the laser beam using a pair of galvanometric mirrors. The resulting backscattered light from the scene is collected by the same mirrors and focussed onto a suitable single-point detector, where the image is constructed pixel by pixel. The imaging instrument that was developed in this work is based around an IR optical parametric oscillator (OPO) source with broad tunability, operating in the 2.6 to 3.7 μm (MWIR) and 1.5 to 1.8 μm (shortwave IR, SWIR) spectral regions. The MWIR beam was primarily used as it addressed the fundamental absorption features of the target compounds compared to the overtone and combination bands in the SWIR region, which can be less intense by more than an order of magnitude. We show that a prototype NCI instrument was able to locate hydrocarbon materials at distances up to 15 metres.

Scene-based nonuniformity correction for airborne point target detection systems.

PubMed

Zhou, Dabiao; Wang, Dejiang; Huo, Lijun; Liu, Rang; Jia, Ping

2017-06-26

Images acquired by airborne infrared search and track (IRST) systems are often characterized by nonuniform noise. In this paper, a scene-based nonuniformity correction method for infrared focal-plane arrays (FPAs) is proposed based on the constant statistics of the received radiation ratios of adjacent pixels. The gain of each pixel is computed recursively based on the ratios between adjacent pixels, which are estimated through a median operation. Then, an elaborate mathematical model describing the error propagation, derived from random noise and the recursive calculation procedure, is established. The proposed method maintains the characteristics of traditional methods in calibrating the whole electro-optics chain, in compensating for temporal drifts, and in not preserving the radiometric accuracy of the system. Moreover, the proposed method is robust since the frame number is the only variant, and is suitable for real-time applications owing to its low computational complexity and simplicity of implementation. The experimental results, on different scenes from a proof-of-concept point target detection system with a long-wave Sofradir FPA, demonstrate the compelling performance of the proposed method.

Passive Fourier-transform infrared spectroscopy of chemical plumes: an algorithm for quantitative interpretation and real-time background removal

NASA Astrophysics Data System (ADS)

Polak, Mark L.; Hall, Jeffrey L.; Herr, Kenneth C.

1995-08-01

We present a ratioing algorithm for quantitative analysis of the passive Fourier-transform infrared spectrum of a chemical plume. We show that the transmission of a near-field plume is given by tau plume = (Lobsd - Lbb-plume)/(Lbkgd - Lbb-plume), where tau _{plume is the frequency-dependent transmission of the plume, L obsd is the spectral radiance of the scene that contains the plume, Lbkgd is the spectral radiance of the same scene without the plume, and Lbb-plume is the spectral radiance of a blackbody at the plume temperature. The algorithm simultaneously achieves background removal, elimination of the spectrometer internal signature, and quantification of the plume spectral transmission. It has applications to both real-time processing for plume visualization and quantitative measurements of plume column densities. The plume temperature (Lbb-plume ), which is not always precisely known, can have a profound effect on the quantitative interpretation of the algorithm and is discussed in detail. Finally, we provide an illustrative example of the use of the algorithm on a trichloroethylene and acetone plume.}

Uniqueness of thermodynamic projector and kinetic basis of molecular individualism

NASA Astrophysics Data System (ADS)

Gorban, Alexander N.; Karlin, Iliya V.

2004-05-01

Three results are presented: First, we solve the problem of persistence of dissipation for reduction of kinetic models. Kinetic equations with thermodynamic Lyapunov functions are studied. Uniqueness of the thermodynamic projector is proven: There exists only one projector which transforms any vector field equipped with the given Lyapunov function into a vector field with the same Lyapunov function for a given anzatz manifold which is not tangent to the Lyapunov function levels. Second, we use the thermodynamic projector for developing the short memory approximation and coarse-graining for general nonlinear dynamic systems. We prove that in this approximation the entropy production increases. ( The theorem about entropy overproduction.) In example, we apply the thermodynamic projector to derive the equations of reduced kinetics for the Fokker-Planck equation. A new class of closures is developed, the kinetic multipeak polyhedra. Distributions of this type are expected in kinetic models with multidimensional instability as universally as the Gaussian distribution appears for stable systems. The number of possible relatively stable states of a nonequilibrium system grows as 2 m, and the number of macroscopic parameters is in order mn, where n is the dimension of configuration space, and m is the number of independent unstable directions in this space. The elaborated class of closures and equations pretends to describe the effects of “molecular individualism”. This is the third result.

Application of infrared spectroscopy and pyrolysis gas chromatography for characterisation of adhesive tapes

NASA Astrophysics Data System (ADS)

Zięba-Palus, Janina; Nowińska, Sabina; Kowalski, Rafał

2016-12-01

Infrared spectroscopy and pyrolysis GC/MS were applied in the comparative analysis of adhesive tapes. By providing information about the polymer composition, it was possible to classify both backings and adhesives of tapes into defined chemical classes. It was found that samples of the same type (of backings and adhesives) and similar infrared spectra can in most cases be effectively differentiated using Py-GC/MS, sometimes based only on the presence of peaks of very low intensity originating from minor components. The results obtained enabled us to draw the conclusion that Py-GC/MS appears to be a valuable analytical technique for examining tapes, which is complementary to infrared spectroscopy. Identification of pyrolysis products enables discrimination of samples. Both methods also provide crucial information that is useful for identification of adhesive tapes found at the crime scene.

Automated Slide Projector

ERIC Educational Resources Information Center

Gould, Mauri

1975-01-01

Describes assembly of a moderately priced synchronized projector and cassette tape recorder using a single channel recorder with a tuned amplifier to separate voice and control tones. Construction requires familiarity with transistors and use of an oscilloscope with an audio signal generator. A picture as well as schematics is provided. (GH)

An Accurate Projector Calibration Method Based on Polynomial Distortion Representation

PubMed Central

Liu, Miao; Sun, Changku; Huang, Shujun; Zhang, Zonghua

2015-01-01

In structure light measurement systems or 3D printing systems, the errors caused by optical distortion of a digital projector always affect the precision performance and cannot be ignored. Existing methods to calibrate the projection distortion rely on calibration plate and photogrammetry, so the calibration performance is largely affected by the quality of the plate and the imaging system. This paper proposes a new projector calibration approach that makes use of photodiodes to directly detect the light emitted from a digital projector. By analyzing the output sequence of the photoelectric module, the pixel coordinates can be accurately obtained by the curve fitting method. A polynomial distortion representation is employed to reduce the residuals of the traditional distortion representation model. Experimental results and performance evaluation show that the proposed calibration method is able to avoid most of the disadvantages in traditional methods and achieves a higher accuracy. This proposed method is also practically applicable to evaluate the geometric optical performance of other optical projection system. PMID:26492247

Orthogonal polynomial projectors for the Projector Augmented Wave (PAW) formalism.

NASA Astrophysics Data System (ADS)

Holzwarth, N. A. W.; Matthews, G. E.; Tackett, A. R.; Dunning, R. B.

1998-03-01

The PAW method for density functional electronic structure calculations developed by Blöchl(Phys. Rev. B 50), 17953 (1994) and also used by our group(Phys. Rev. B 55), 2005 (1997) has numerical advantages of a pseudopotential technique while retaining the physics of an all-electron formalism. We describe a new method for generating the necessary set of atom-centered projector and basis functions, based on choosing the projector functions from a set of orthogonal polynomials multiplied by a localizing weight factor. Numerical benefits of the new scheme result from having direct control of the shape of the projector functions and from the use of a simple repulsive local potential term to eliminate ``ghost state" problems, which can haunt calculations of this kind. We demonstrate the method by calculating the cohesive energies of CaF2 and Mo and the density of states of CaMoO4 which shows detailed agreement with LAPW results over a 66 eV range of energy including upper core, valence, and conduction band states.

Effects of mold design of aspheric projector lens for head up display

NASA Astrophysics Data System (ADS)

Chen, Chao-Chang A.; Tang, Jyun-Cing; Teng, Lin-Ming

2010-08-01

This paper investigates the mold design and related effects on an aspheric projector lens for Head Up Display (HUD) with injection molding process. Injection flow analysis with a commercial software, Moldex3D has been used to simulate this projector lens for filling, packing, shrinkage, and flow-induced residual stress. This projector lens contains of variant thickness due to different aspheric design on both surfaces. Defects may be induced as the melt front from the gate into the cavity with jet-flow phenomenon, short shot, weld line, and even shrinkage. Thus, this paper performs a gate design to find the significant parameters including injection velocity, melt temperature, and mold temperature. After simulation by the Moldex3D, gate design for the final assembly of Head Up Display (HUD) has been obtained and then experimental tests have been proceeded for verification of short-shot, weight variation, and flow-induced stress. Moreover, warpage analysis of the Head Up Display (HUD) can be integrated with the optical design specification in future work.

Studying the Earth from space

USGS Publications Warehouse

,

1981-01-01

scene, as man sees it, on film sensitive to that part of the electromagnetic spectrum called visible energy. Electromagnetic energy travels in waves of various lengths; most are invisible to the human eye. Wavelengths progressively longer than those that the eye can see are infrared and microwave. Wavelengths progressively shorter than the eye can see are ultraviolet, X-rays, and gamma rays.

Coherent infrared imaging camera (CIRIC)

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

Hutchinson, D.P.; Simpson, M.L.; Bennett, C.A.

1995-07-01

New developments in 2-D, wide-bandwidth HgCdTe (MCT) and GaAs quantum-well infrared photodetectors (QWIP) coupled with Monolithic Microwave Integrated Circuit (MMIC) technology are now making focal plane array coherent infrared (IR) cameras viable. Unlike conventional IR cameras which provide only thermal data about a scene or target, a coherent camera based on optical heterodyne interferometry will also provide spectral and range information. Each pixel of the camera, consisting of a single photo-sensitive heterodyne mixer followed by an intermediate frequency amplifier and illuminated by a separate local oscillator beam, constitutes a complete optical heterodyne receiver. Applications of coherent IR cameras are numerousmore » and include target surveillance, range detection, chemical plume evolution, monitoring stack plume emissions, and wind shear detection.« less

A Formulation of Quantum Field Theory Realizing a Sea of Interacting Dirac Particles

NASA Astrophysics Data System (ADS)

Finster, Felix

2011-08-01

In this survey article, we explain a few ideas behind the fermionic projector approach and summarize recent results which clarify the connection to quantum field theory. The fermionic projector is introduced, which describes the physical system by a collection of Dirac states, including the states of the Dirac sea. Formulating the interaction by an action principle for the fermionic projector, we obtain a consistent description of interacting quantum fields which reproduces the results of perturbative quantum field theory. We find a new mechanism for the generation of boson masses and obtain small corrections to the field equations which violate causality.

Overhead Projector Demonstrations: Some Ideas from the Past.

ERIC Educational Resources Information Center

Kolb, Doris

1987-01-01

Describes nine chemistry demonstrations that can be done using an overhead projector. Includes demonstrations on common ion effect, crystal formation from supersaturated solutions, making iron positive with nitric acid, optical activity, carbon dioxide in human breath, amphoteric hydroxides, the surface tension of mercury, and natural acid-base…

Polarimetric infrared imaging simulation of a synthetic sea surface with Mie scattering.

PubMed

He, Si; Wang, Xia; Xia, Runqiu; Jin, Weiqi; Liang, Jian'an

2018-03-01

A novel method to simulate the polarimetric infrared imaging of a synthetic sea surface with atmospheric Mie scattering effects is presented. The infrared emission, multiple reflections, and infrared polarization of the sea surface and the Mie scattering of aerosols are all included for the first time. At first, a new approach to retrieving the radiative characteristics of a wind-roughened sea surface is introduced. A two-scale method of sea surface realization and the inverse ray tracing of light transfer calculation are combined and executed simultaneously, decreasing the consumption of time and memory dramatically. Then the scattering process that the infrared light emits from the sea surface and propagates in the aerosol particles is simulated with a polarized light Monte Carlo model. Transformations of the polarization state of the light are calculated with the Mie theory. Finally, the polarimetric infrared images of the sea surface of different environmental conditions and detection parameters are generated based on the scattered light detected by the infrared imaging polarimeter. The results of simulation examples show that our polarimetric infrared imaging simulation can be applied to predict the infrared polarization characteristics of the sea surface, model the oceanic scene, and guide the detection in the oceanic environment.

Video System Highlights Hydrogen Fires

NASA Technical Reports Server (NTRS)

Youngquist, Robert C.; Gleman, Stuart M.; Moerk, John S.

1992-01-01

Video system combines images from visible spectrum and from three bands in infrared spectrum to produce color-coded display in which hydrogen fires distinguished from other sources of heat. Includes linear array of 64 discrete lead selenide mid-infrared detectors operating at room temperature. Images overlaid on black and white image of same scene from standard commercial video camera. In final image, hydrogen fires appear red; carbon-based fires, blue; and other hot objects, mainly green and combinations of green and red. Where no thermal source present, image remains in black and white. System enables high degree of discrimination between hydrogen flames and other thermal emitters.

Beamforming using subspace estimation from a diagonally averaged sample covariance.

PubMed

Quijano, Jorge E; Zurk, Lisa M

2017-08-01

The potential benefit of a large-aperture sonar array for high resolution target localization is often challenged by the lack of sufficient data required for adaptive beamforming. This paper introduces a Toeplitz-constrained estimator of the clairvoyant signal covariance matrix corresponding to multiple far-field targets embedded in background isotropic noise. The estimator is obtained by averaging along subdiagonals of the sample covariance matrix, followed by covariance extrapolation using the method of maximum entropy. The sample covariance is computed from limited data snapshots, a situation commonly encountered with large-aperture arrays in environments characterized by short periods of local stationarity. Eigenvectors computed from the Toeplitz-constrained covariance are used to construct signal-subspace projector matrices, which are shown to reduce background noise and improve detection of closely spaced targets when applied to subspace beamforming. Monte Carlo simulations corresponding to increasing array aperture suggest convergence of the proposed projector to the clairvoyant signal projector, thereby outperforming the classic projector obtained from the sample eigenvectors. Beamforming performance of the proposed method is analyzed using simulated data, as well as experimental data from the Shallow Water Array Performance experiment.

Hyperspectral and Hypertemporal Longwave Infrared Data Characterization

NASA Astrophysics Data System (ADS)

Jeganathan, Nirmalan

The Army Research Lab conducted a persistent imaging experiment called the Spectral and Polarimetric Imagery Collection Experiment (SPICE) in 2012 and 2013 which focused on collecting and exploiting long wave infrared hyperspectral and polarimetric imagery. A part of this dataset was made for public release for research and development purposes. This thesis investigated the hyperspectral portion of this released dataset through data characterization and scene characterization of man-made and natural objects. First, the data were contrasted with MODerate resolution atmospheric TRANsmission (MODTRAN) results and found to be comparable. Instrument noise was characterized using an in-scene black panel, and was found to be comparable with the sensor manufacturer's specication. The temporal and spatial variation of certain objects in the scene were characterized. Temporal target detection was conducted on man-made objects in the scene using three target detection algorithms: spectral angle mapper (SAM), spectral matched lter (SMF) and adaptive coherence/cosine estimator (ACE). SMF produced the best results for detecting the targets when the training and testing data originated from different time periods, with a time index percentage result of 52.9%. Unsupervised and supervised classification were conducted using spectral and temporal target signatures. Temporal target signatures produced better visual classification than spectral target signature for unsupervised classification. Supervised classification yielded better results using the spectral target signatures, with a highest weighted accuracy of 99% for 7-class reference image. Four emissivity retrieval algorithms were applied on this dataset. However, the retrieved emissivities from all four methods did not represent true material emissivity and could not be used for analysis. This spectrally and temporally rich dataset enabled to conduct analysis that was not possible with other data collections. Regarding future work, applying noise-reduction techniques before applying temperature-emissivity retrieval algorithms may produce more realistic emissivity values, which could be used for target detection and material identification.

Mid-infrared hyperspectral imaging for the detection of explosive compounds

NASA Astrophysics Data System (ADS)

Ruxton, K.; Robertson, G.; Miller, W.; Malcolm, G. P. A.; Maker, G. T.

2012-10-01

Active hyperspectral imaging is a valuable tool in a wide range of applications. A developing market is the detection and identification of energetic compounds through analysis of the resulting absorption spectrum. This work presents a selection of results from a prototype mid-infrared (MWIR) hyperspectral imaging instrument that has successfully been used for compound detection at a range of standoff distances. Active hyperspectral imaging utilises a broadly tunable laser source to illuminate the scene with light over a range of wavelengths. While there are a number of illumination methods, this work illuminates the scene by raster scanning the laser beam using a pair of galvanometric mirrors. The resulting backscattered light from the scene is collected by the same mirrors and directed and focussed onto a suitable single-point detector, where the image is constructed pixel by pixel. The imaging instrument that was developed in this work is based around a MWIR optical parametric oscillator (OPO) source with broad tunability, operating at 2.6 μm to 3.7 μm. Due to material handling procedures associated with explosive compounds, experimental work was undertaken initially using simulant compounds. A second set of compounds that was tested alongside the simulant compounds is a range of confusion compounds. By having the broad wavelength tunability of the OPO, extended absorption spectra of the compounds could be obtained to aid in compound identification. The prototype imager instrument has successfully been used to record the absorption spectra for a range of compounds from the simulant and confusion sets and current work is now investigating actual explosive compounds. The authors see a very promising outlook for the MWIR hyperspectral imager. From an applications point of view this format of imaging instrument could be used for a range of standoff, improvised explosive device (IED) detection applications and potential incident scene forensic investigation.

A Visual Servoing-Based Method for ProCam Systems Calibration

PubMed Central

Berry, Francois; Aider, Omar Ait; Mosnier, Jeremie

2013-01-01

Projector-camera systems are currently used in a wide field of applications, such as 3D reconstruction and augmented reality, and can provide accurate measurements, depending on the configuration and calibration. Frequently, the calibration task is divided into two steps: camera calibration followed by projector calibration. The latter still poses certain problems that are not easy to solve, such as the difficulty in obtaining a set of 2D–3D points to compute the projection matrix between the projector and the world. Existing methods are either not sufficiently accurate or not flexible. We propose an easy and automatic method to calibrate such systems that consists in projecting a calibration pattern and superimposing it automatically on a known printed pattern. The projected pattern is provided by a virtual camera observing a virtual pattern in an OpenGL model. The projector displays what the virtual camera visualizes. Thus, the projected pattern can be controlled and superimposed on the printed one with the aid of visual servoing. Our experimental results compare favorably with those of other methods considering both usability and accuracy. PMID:24084121

The Overhead Projector in the Mathematics Classroom.

ERIC Educational Resources Information Center

Lenchner, George

The first section of this pamphlet illustrates and describes the overhead projector, and discusses several of its advantages over other projection devises, including its simplicity of operation, conservation of class time, dynamic effects, image size, etc. The second section describes in some detail materials and methods used to make visuals, then…

Using the Overhead Projector as a Light Source for Physics Demonstrations

ERIC Educational Resources Information Center

Mak, Se-Yuen

2006-01-01

This article illustrates how the overhead projector can be used as a light source in some peculiar ways for physics demonstrations. Five examples are included: (1) Study of chromatic aberration; (2) Making giant Newton's rings; (3) Comparison of the rate of heat absorption by different surfaces; (4) Demonstration of greenhouse effect; and (5)…

The remote sensing of algae

NASA Technical Reports Server (NTRS)

Thorne, J. F.

1977-01-01

State agencies need rapid, synoptic and inexpensive methods for lake assessment to comply with the 1972 Amendments to the Federal Water Pollution Control Act. Low altitude aerial photography may be useful in providing information on algal type and quantity. Photography must be calibrated properly to remove sources of error including airlight, surface reflectance and scene-to-scene illumination differences. A 550-nm narrow wavelength band black and white photographic exposure provided a better correlation to algal biomass than either red or infrared photographic exposure. Of all the biomass parameters tested, depth-integrated chlorophyll a concentration correlated best to remote sensing data. Laboratory-measured reflectance of selected algae indicate that different taxonomic classes of algae may be discriminated on the basis of their reflectance spectra.

Recent Experiments Conducted with the Wide-Field Imaging Interferometry Testbed (WIIT)

NASA Technical Reports Server (NTRS)

Leisawitz, David T.; Juanola-Parramon, Roser; Bolcar, Matthew; Iacchetta, Alexander S.; Maher, Stephen F.; Rinehart, Stephen A.

2016-01-01

The Wide-field Imaging Interferometry Testbed (WIIT) was developed at NASA's Goddard Space Flight Center to demonstrate and explore the practical limitations inherent in wide field-of-view double Fourier (spatio-spectral) interferometry. The testbed delivers high-quality interferometric data and is capable of observing spatially and spectrally complex hyperspectral test scenes. Although WIIT operates at visible wavelengths, by design the data are representative of those from a space-based far-infrared observatory. We used WIIT to observe a calibrated, independently characterized test scene of modest spatial and spectral complexity, and an astronomically realistic test scene of much greater spatial and spectral complexity. This paper describes the experimental setup, summarizes the performance of the testbed, and presents representative data.

Interpretation of multispectral and infrared thermal surveys of the Suez Canal Zone, Egypt

NASA Technical Reports Server (NTRS)

Elshazly, E. M.; Hady, M. A. A. H.; Hafez, M. A. A.; Salman, A. B.; Morsy, M. A.; Elrakaiby, M. M.; Alaassy, I. E. E.; Kamel, A. F.

1977-01-01

Remote sensing airborne surveys were conducted, as part of the plan of rehabilitation, of the Suez Canal Zone using I2S multispectral camera and Bendix LN-3 infrared passive scanner. The multispectral camera gives four separate photographs for the same scene in the blue, green, red, and near infrared bands. The scanner was operated in the microwave bands of 8 to 14 microns and the thermal surveying was carried out both at night and in the day time. The surveys, coupled with intensive ground investigations, were utilized in the construction of new geological, structural lineation and drainage maps for the Suez Canal Zone on a scale of approximately 1:20,000, which are superior to the maps made by normal aerial photography. A considerable number of anomalies belonging to various types were revealed through the interpretation of the executed multispectral and infrared thermal surveys.

E-Learning Technologies and Adult Education in Nigeria

ERIC Educational Resources Information Center

Oguzor, Nkasiobi Silas

2011-01-01

The internet has proved to be one of the greatest learning resources available in the 21st Century. Modern education is becoming progressively more dynamic. Internet has helped man to see the other part of the world at the click of a mouse. Various forms of instructional technologies such as the overhead projector, opaque projector, filmstrip and…

Projector-Camera Systems for Immersive Training

DTIC Science & Technology

2006-01-01

average to a sequence of 100 captured distortion corrected images. The OpenCV library [ OpenCV ] was used for camera calibration. To correct for...rendering application [Treskunov, Pair, and Swartout, 2004]. It was transposed to take into account different matrix conventions between OpenCV and...Screen Imperfections. Proc. Workshop on Projector-Camera Systems (PROCAMS), Nice, France, IEEE. OpenCV : Open Source Computer Vision. [Available

A closed-loop control-loading system

NASA Technical Reports Server (NTRS)

Ashworth, B. R.; Parrish, R. V.

1979-01-01

Langley Differential Maneuvering Simulator (DMS) realistically simulates two aircraft operating in differential mode. It consists of two identical fixed-base cockpits and dome projection systems. Each projection system consists of sky/Earth projector and target-image generator and projector. Although programmable control forces are small part of overall system, they play large role in providing pilot with kinesthetic cues.

Infrared small target detection based on multiscale center-surround contrast measure

NASA Astrophysics Data System (ADS)

Fu, Hao; Long, Yunli; Zhu, Ran; An, Wei

2018-04-01

Infrared(IR) small target detection plays a critical role in the Infrared Search And Track (IRST) system. Although it has been studied for years, there are some difficulties remained to the clutter environment. According to the principle of human discrimination of small targets from a natural scene that there is a signature of discontinuity between the object and its neighboring regions, we develop an efficient method for infrared small target detection called multiscale centersurround contrast measure (MCSCM). First, to determine the maximum neighboring window size, an entropy-based window selection technique is used. Then, we construct a novel multiscale center-surround contrast measure to calculate the saliency map. Compared with the original image, the MCSCM map has less background clutters and noise residual. Subsequently, a simple threshold is used to segment the target. Experimental results show our method achieves better performance.

Combined use of visible, reflected infrared, and thermal infrared images for mapping Hawaiian lava flows

NASA Technical Reports Server (NTRS)

Abrams, Michael; Abbott, Elsa; Kahle, Anne

1991-01-01

The weathering of Hawaiian basalts is accompanied by chemical and physical changes of the surfaces. These changes have been mapped using remote sensing data from the visible and reflected infrared and thermal infrared wavelength regions. They are related to the physical breakdown of surface chill coats, the development and erosion of silica coatings, the oxidation of mafic minerals, and the development of vegetation cover. These effects show systematic behavior with age and can be mapped using the image data and related to relative ages of pahoehoe and aa flows. The thermal data are sensitive to silica rind development and fine structure of the scene; the reflectance data show the degree of oxidation and differentiate vegetation from aa and cinders. Together, data from the two wavelength regions show more than either separately. The combined data potentially provide a powerful tool for mapping basalt flows in arid to semiarid volcanic environments.

Weber-aware weighted mutual information evaluation for infrared-visible image fusion

NASA Astrophysics Data System (ADS)

Luo, Xiaoyan; Wang, Shining; Yuan, Ding

2016-10-01

A performance metric for infrared and visible image fusion is proposed based on Weber's law. To indicate the stimulus of source images, two Weber components are provided. One is differential excitation to reflect the spectral signal of visible and infrared images, and the other is orientation to capture the scene structure feature. By comparing the corresponding Weber component in infrared and visible images, the source pixels can be marked with different dominant properties in intensity or structure. If the pixels have the same dominant property label, the pixels are grouped to calculate the mutual information (MI) on the corresponding Weber components between dominant source and fused images. Then, the final fusion metric is obtained via weighting the group-wise MI values according to the number of pixels in different groups. Experimental results demonstrate that the proposed metric performs well on popular image fusion cases and outperforms other image fusion metrics.

Target Detection over the Diurnal Cycle Using a Multispectral Infrared Sensor

PubMed Central

Zhao, Huijie; Ji, Zheng; Li, Na; Gu, Jianrong; Li, Yansong

2016-01-01

When detecting a target over the diurnal cycle, a conventional infrared thermal sensor might lose the target due to the thermal crossover, which could happen at any time throughout the day when the infrared image contrast between target and background in a scene is indistinguishable due to the temperature variation. In this paper, the benefits of using a multispectral-based infrared sensor over the diurnal cycle have been shown. Firstly, a brief theoretical analysis on how the thermal crossover influences a conventional thermal sensor, within the conditions where the thermal crossover would happen and why the mid-infrared (3~5 μm) multispectral technology is effective, is presented. Furthermore, the effectiveness of this technology is also described and we describe how the prototype design and multispectral technology is employed to help solve the thermal crossover detection problem. Thirdly, several targets are set up outside and imaged in the field experiment over a 24-h period. The experimental results show that the multispectral infrared imaging system can enhance the contrast of the detected images and effectively solve the failure of the conventional infrared sensor during the diurnal cycle, which is of great significance for infrared surveillance applications. PMID:28036073

Dissolving Carboxylic Acids and Primary Amines on the Overhead Projector

ERIC Educational Resources Information Center

Solomon, Sally D.; Rutkowsky, Susan A.

2010-01-01

Liquid carboxylic acids (or primary amines) with limited solubility in water are dissolved by addition of aqueous sodium hydroxide (or hydrochloric acid) on the stage of an overhead projector using simple glassware and very small quantities of chemicals. This effective and colorful demonstration can be used to accompany discussions of the…

Perturbative description of the fermionic projector: Normalization, causality, and Furry's theorem

NASA Astrophysics Data System (ADS)

Finster, Felix; Tolksdorf, Jürgen

2014-05-01

The causal perturbation expansion of the fermionic projector is performed with a contour integral method. Different normalization conditions are analyzed. It is shown that the corresponding light-cone expansions are causal in the sense that they only involve bounded line integrals. For the resulting loop diagrams we prove a generalized Furry theorem.

Real time imaging and infrared background scene analysis using the Naval Postgraduate School infrared search and target designation (NPS-IRSTD) system

NASA Astrophysics Data System (ADS)

Bernier, Jean D.

1991-09-01

The imaging in real time of infrared background scenes with the Naval Postgraduate School Infrared Search and Target Designation (NPS-IRSTD) System was achieved through extensive software developments in protected mode assembly language on an Intel 80386 33 MHz computer. The new software processes the 512 by 480 pixel images directly in the extended memory area of the computer where the DT-2861 frame grabber memory buffers are mapped. Direct interfacing, through a JDR-PR10 prototype card, between the frame grabber and the host computer AT bus enables each load of the frame grabber memory buffers to be effected under software control. The protected mode assembly language program can refresh the display of a six degree pseudo-color sector in the scanner rotation within the two second period of the scanner. A study of the imaging properties of the NPS-IRSTD is presented with preliminary work on image analysis and contrast enhancement of infrared background scenes.

Target Detection over the Diurnal Cycle Using a Multispectral Infrared Sensor.

PubMed

Zhao, Huijie; Ji, Zheng; Li, Na; Gu, Jianrong; Li, Yansong

2016-12-29

When detecting a target over the diurnal cycle, a conventional infrared thermal sensor might lose the target due to the thermal crossover, which could happen at any time throughout the day when the infrared image contrast between target and background in a scene is indistinguishable due to the temperature variation. In this paper, the benefits of using a multispectral-based infrared sensor over the diurnal cycle have been shown. Firstly, a brief theoretical analysis on how the thermal crossover influences a conventional thermal sensor, within the conditions where the thermal crossover would happen and why the mid-infrared (3~5 μm) multispectral technology is effective, is presented. Furthermore, the effectiveness of this technology is also described and we describe how the prototype design and multispectral technology is employed to help solve the thermal crossover detection problem. Thirdly, several targets are set up outside and imaged in the field experiment over a 24-h period. The experimental results show that the multispectral infrared imaging system can enhance the contrast of the detected images and effectively solve the failure of the conventional infrared sensor during the diurnal cycle, which is of great significance for infrared surveillance applications.

An infrared/video fusion system for military robotics

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

Davis, A.W.; Roberts, R.S.

1997-08-05

Sensory information is critical to the telerobotic operation of mobile robots. In particular, visual sensors are a key component of the sensor package on a robot engaged in urban military operations. Visual sensors provide the robot operator with a wealth of information including robot navigation and threat assessment. However, simple countermeasures such as darkness, smoke, or blinding by a laser, can easily neutralize visual sensors. In order to provide a robust visual sensing system, an infrared sensor is required to augment the primary visual sensor. An infrared sensor can acquire useful imagery in conditions that incapacitate a visual sensor. Amore » simple approach to incorporating an infrared sensor into the visual sensing system is to display two images to the operator: side-by-side visual and infrared images. However, dual images might overwhelm the operator with information, and result in degraded robot performance. A better solution is to combine the visual and infrared images into a single image that maximizes scene information. Fusing visual and infrared images into a single image demands balancing the mixture of visual and infrared information. Humans are accustom to viewing and interpreting visual images. They are not accustom to viewing or interpreting infrared images. Hence, the infrared image must be used to enhance the visual image, not obfuscate it.« less

Overhead Projector Spectrum of Polymethine Dye: A Physical Chemistry Demonstration.

ERIC Educational Resources Information Center

Solomon, Sally; Hur, Chinhyu

1995-01-01

Encourages the incorporation into lecture of live experiments that can be predicted or interpreted with abstract models. A demonstration is described where the position of the predominant peak of 1,1'-diethyl-4,4'-cyanine iodide is measured in class using an overhead projector spectrometer, then predicted using the model of a particle in a…

A Volumetric Flask as a Projector

ERIC Educational Resources Information Center

Limsuwan, P.; Asanithi, P.; Thongpool, V.; Piriyawong, V.; Limsuwan, S.

2012-01-01

A lens based on liquid in the confined volume of a volumetric flask was presented as a potential projector to observe microscopic floating organisms or materials. In this experiment, a mosquito larva from a natural pond was selected as a demonstration sample. By shining a light beam from a laser pointer of any visible wavelength through the…

A Mobile Mixed-Reality Environment for Children's Storytelling Using a Handheld Projector and a Robot

ERIC Educational Resources Information Center

Sugimoto, Masanori

2011-01-01

This paper describes a system called GENTORO that uses a robot and a handheld projector for supporting children's storytelling activities. GENTORO differs from many existing systems in that children can make a robot play their own story in a physical space augmented by mixed-reality technologies. Pilot studies have been conducted to clarify the…

Room-temperature quantum noise limited spectrometry and methods of the same

DOEpatents

Stevens, Charles G.; Tringe, Joseph W.; Cunningham, Christopher T.

2016-08-02

In one embodiment, a heterodyne detection system for detecting light includes a first input aperture configured to receive first light from a scene input, a second input aperture configured to receive second light from a local oscillator input, a broadband local oscillator configured to provide the second light to the second input aperture, a dispersive element configured to disperse the first light and the second light, and a final condensing lens coupled to an infrared detector. The final condensing lens is configured to concentrate incident light from a primary condensing lens onto the infrared detector, and the infrared detector is a square-law detector capable of sensing the frequency difference between the first light and the second light. More systems and methods for detecting light are described according to other embodiments.

Room-temperature quantum noise limited spectrometry and methods of the same

DOEpatents

Stevens, Charles G.; Tringe, Joseph W.; Cunningham, Christopher Thomas

2014-08-26

In one embodiment, a heterodyne detection system for detecting light includes a first input aperture adapted for receiving first light from a scene input, a second input aperture adapted for receiving second light from a local oscillator input, a broadband local oscillator adapted for providing the second light to the second input aperture, a dispersive element adapted for dispersing the first light and the second light, and a final condensing lens coupled to an infrared detector. The final condensing lens is adapted for concentrating incident light from a primary condensing lens onto the infrared detector, and the infrared detector is a square-law detector capable of sensing the frequency difference between the first light and the second light. More systems and methods for detecting light are described according to other embodiments.

Multispectral linear array visible and shortwave infrared sensors

NASA Astrophysics Data System (ADS)

Tower, J. R.; Warren, F. B.; Pellon, L. E.; Strong, R.; Elabd, H.; Cope, A. D.; Hoffmann, D. M.; Kramer, W. M.; Longsderff, R. W.

1984-08-01

All-solid state pushbroom sensors for multispectral linear array (MLA) instruments to replace mechanical scanners used on LANDSAT satellites are introduced. A buttable, four-spectral-band, linear-format charge coupled device (CCD) and a buttable, two-spectral-band, linear-format, shortwave infrared CCD are described. These silicon integrated circuits may be butted end to end to provide multispectral focal planes with thousands of contiguous, in-line photosites. The visible CCD integrated circuit is organized as four linear arrays of 1024 pixels each. Each array views the scene in a different spectral window, resulting in a four-band sensor. The shortwave infrared (SWIR) sensor is organized as 2 linear arrays of 512 detectors each. Each linear array is optimized for performance at a different wavelength in the SWIR band.

We Have Met Our Past and Our Future: Thanks for the Walk down Memory Lane

ERIC Educational Resources Information Center

Wiseman, Robert C.

2006-01-01

In this article, the author takes the readers for a walk down memory lane on the use of teaching aids. He shares his experience of the good old days of Audio Visual--opaque projector, motion pictures/films, recorders, and overhead projector. Computers have arrived, and now people can make graphics, pictures, motion pictures, and many different…

Neonatal infrared thermography imaging: Analysis of heat flux during different clinical scenarios

NASA Astrophysics Data System (ADS)

Abbas, Abbas K.; Heimann, Konrad; Blazek, Vladimir; Orlikowsky, Thorsten; Leonhardt, Steffen

2012-11-01

IntroductionAn accurate skin temperature measurement of Neonatal Infrared Thermography (NIRT) imaging requires an appropriate calibration process for compensation of external effects (e.g. variation of environmental temperature, variable air velocity or humidity). Although modern infrared cameras can perform such calibration, an additional compensation is required for highly accurate thermography. This compensation which corrects any temperature drift should occur during the NIRT imaging process. We introduce a compensation technique which is based on modeling the physical interactions within the measurement scene and derived the detected temperature signal of the object. Materials and methodsIn this work such compensation was performed for different NIRT imaging application in neonatology (e.g. convective incubators, kangaroo mother care (KMC), and an open radiant warmer). The spatially distributed temperatures of 12 preterm infants (average gestation age 31 weeks) were measured under these different infant care arrangements (i.e. closed care system like a convective incubator, and open care system like kangaroo mother care, and open radiant warmer). ResultsAs errors in measurement of temperature were anticipated, a novel compensation method derived from infrared thermography of the neonate's skin was developed. Moreover, the differences in temperature recording for the 12 preterm infants varied from subject to subject. This variation could be arising from individual experimental setting applied to the same region of interest over the neonate's body. The experimental results for the model-based corrections is verified over the selected patient group. ConclusionThe proposed technique relies on applying model-based correction to the measured temperature and reducing extraneous errors during NIRT. This application specific method is based on different heat flux compartments present in neonatal thermography scene. Furthermore, these results are considered to be groundwork for further investigation, especially when using NIRT imaging arrangement with additional compensation settings together with reference temperature measurements.

Ripple FPN reduced algorithm based on temporal high-pass filter and hardware implementation

NASA Astrophysics Data System (ADS)

Li, Yiyang; Li, Shuo; Zhang, Zhipeng; Jin, Weiqi; Wu, Lei; Jin, Minglei

2016-11-01

Cooled infrared detector arrays always suffer from undesired Ripple Fixed-Pattern Noise (FPN) when observe the scene of sky. The Ripple Fixed-Pattern Noise seriously affect the imaging quality of thermal imager, especially for small target detection and tracking. It is hard to eliminate the FPN by the Calibration based techniques and the current scene-based nonuniformity algorithms. In this paper, we present a modified space low-pass and temporal high-pass nonuniformity correction algorithm using adaptive time domain threshold (THP&GM). The threshold is designed to significantly reduce ghosting artifacts. We test the algorithm on real infrared in comparison to several previously published methods. This algorithm not only can effectively correct common FPN such as Stripe, but also has obviously advantage compared with the current methods in terms of detail protection and convergence speed, especially for Ripple FPN correction. Furthermore, we display our architecture with a prototype built on a Xilinx Virtex-5 XC5VLX50T field-programmable gate array (FPGA). The hardware implementation of the algorithm based on FPGA has two advantages: (1) low resources consumption, and (2) small hardware delay (less than 20 lines). The hardware has been successfully applied in actual system.

Enhanced Video-Oculography System

NASA Technical Reports Server (NTRS)

Moore, Steven T.; MacDougall, Hamish G.

2009-01-01

A previously developed video-oculography system has been enhanced for use in measuring vestibulo-ocular reflexes of a human subject in a centrifuge, motor vehicle, or other setting. The system as previously developed included a lightweight digital video camera mounted on goggles. The left eye was illuminated by an infrared light-emitting diode via a dichroic mirror, and the camera captured images of the left eye in infrared light. To extract eye-movement data, the digitized video images were processed by software running in a laptop computer. Eye movements were calibrated by having the subject view a target pattern, fixed with respect to the subject s head, generated by a goggle-mounted laser with a diffraction grating. The system as enhanced includes a second camera for imaging the scene from the subject s perspective, and two inertial measurement units (IMUs) for measuring linear accelerations and rates of rotation for computing head movements. One IMU is mounted on the goggles, the other on the centrifuge or vehicle frame. All eye-movement and head-motion data are time-stamped. In addition, the subject s point of regard is superimposed on each scene image to enable analysis of patterns of gaze in real time.

Interactive Projector as an Interactive Teaching Tool in the Classroom: Evaluating Teaching Efficiency and Interactivity

ERIC Educational Resources Information Center

Liu, Li-Ying; Cheng, Meng-Tzu

2015-01-01

This study reports on a measurement that is used to investigate interactivity in the classrooms and examines the impact of integrating the interactive projector into middle school science classes on classroom interactivity and students' biology learning. A total of 126 7th grade Taiwanese students were involved in the study and quasi-experimental…

76 FR 30180 - Notice of Issuance of Final Determination Concerning Pocket Projectors

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-24

..., and adhering by electrostatic means. The finished projector will undergo a series of tests in Taiwan: A pre-test, a run-in test, and a function test. The pre-test consists of: ensuring that the... the projector is turned on (developed in Taiwan), (2) test patterns that are projected on the screen...

Temporal high-pass non-uniformity correction algorithm based on grayscale mapping and hardware implementation

NASA Astrophysics Data System (ADS)

Jin, Minglei; Jin, Weiqi; Li, Yiyang; Li, Shuo

2015-08-01

In this paper, we propose a novel scene-based non-uniformity correction algorithm for infrared image processing-temporal high-pass non-uniformity correction algorithm based on grayscale mapping (THP and GM). The main sources of non-uniformity are: (1) detector fabrication inaccuracies; (2) non-linearity and variations in the read-out electronics and (3) optical path effects. The non-uniformity will be reduced by non-uniformity correction (NUC) algorithms. The NUC algorithms are often divided into calibration-based non-uniformity correction (CBNUC) algorithms and scene-based non-uniformity correction (SBNUC) algorithms. As non-uniformity drifts temporally, CBNUC algorithms must be repeated by inserting a uniform radiation source which SBNUC algorithms do not need into the view, so the SBNUC algorithm becomes an essential part of infrared imaging system. The SBNUC algorithms' poor robustness often leads two defects: artifacts and over-correction, meanwhile due to complicated calculation process and large storage consumption, hardware implementation of the SBNUC algorithms is difficult, especially in Field Programmable Gate Array (FPGA) platform. The THP and GM algorithm proposed in this paper can eliminate the non-uniformity without causing defects. The hardware implementation of the algorithm only based on FPGA has two advantages: (1) low resources consumption, and (2) small hardware delay: less than 20 lines, it can be transplanted to a variety of infrared detectors equipped with FPGA image processing module, it can reduce the stripe non-uniformity and the ripple non-uniformity.

Sensor performance analysis

NASA Technical Reports Server (NTRS)

Montgomery, H. E.; Ostrow, H.; Ressler, G. M.

1990-01-01

The theory is described and the equations required to design are developed and the performance of electro-optical sensor systems that operate from the visible through the thermal infrared spectral regions are analyzed. Methods to compute essential optical and detector parameters, signal-to-noise ratio, MTF, and figures of merit such as NE delta rho and NE delta T are developed. A set of atmospheric tables are provided to determine scene radiance in the visible spectral region. The Planck function is used to determine radiance in the infrared. The equations developed were incorporated in a spreadsheet so that a wide variety of sensor studies can be rapidly and efficiently conducted.

Autocalibration of a projector-camera system.

PubMed

Okatani, Takayuki; Deguchi, Koichiro

2005-12-01

This paper presents a method for calibrating a projector-camera system that consists of multiple projectors (or multiple poses of a single projector), a camera, and a planar screen. We consider the problem of estimating the homography between the screen and the image plane of the camera or the screen-camera homography, in the case where there is no prior knowledge regarding the screen surface that enables the direct computation of the homography. It is assumed that the pose of each projector is unknown while its internal geometry is known. Subsequently, it is shown that the screen-camera homography can be determined from only the images projected by the projectors and then obtained by the camera, up to a transformation with four degrees of freedom. This transformation corresponds to arbitrariness in choosing a two-dimensional coordinate system on the screen surface and when this coordinate system is chosen in some manner, the screen-camera homography as well as the unknown poses of the projectors can be uniquely determined. A noniterative algorithm is presented, which computes the homography from three or more images. Several experimental results on synthetic as well as real images are shown to demonstrate the effectiveness of the method.

Salient contour extraction from complex natural scene in night vision image

NASA Astrophysics Data System (ADS)

Han, Jing; Yue, Jiang; Zhang, Yi; Bai, Lian-fa

2014-03-01

The theory of center-surround interaction in non-classical receptive field can be applied in night vision information processing. In this work, an optimized compound receptive field modulation method is proposed to extract salient contour from complex natural scene in low-light-level (LLL) and infrared images. The kernel idea is that multi-feature analysis can recognize the inhomogeneity in modulatory coverage more accurately and that center and surround with the grouping structure satisfying Gestalt rule deserves high connection-probability. Computationally, a multi-feature contrast weighted inhibition model is presented to suppress background and lower mutual inhibition among contour elements; a fuzzy connection facilitation model is proposed to achieve the enhancement of contour response, the connection of discontinuous contour and the further elimination of randomly distributed noise and texture; a multi-scale iterative attention method is designed to accomplish dynamic modulation process and extract contours of targets in multi-size. This work provides a series of biologically motivated computational visual models with high-performance for contour detection from cluttered scene in night vision images.

Design of a Computer-Controlled, Random-Access Slide Projector Interface. Final Report (April 1974 - November 1974).

ERIC Educational Resources Information Center

Kirby, Paul J.; And Others

The design, development, test, and evaluation of an electronic hardware device interfacing a commercially available slide projector with a plasma panel computer terminal is reported. The interface device allows an instructional computer program to select slides for viewing based upon the lesson student situation parameters of the instructional…

The Use of the Overhead Projector in Teaching Composition.

ERIC Educational Resources Information Center

Bissex, Henry

The overhead projector, used as a controllable blackboard or bulletin board in the teaching of writing, extends the range of teaching techniques so that an instructor may (1) prepare, in advance, handwritten sheets of film--test questions, pupils' sentences, quotations, short poems--to be shown in any order or form; (2) use pictures, graphics, or…

Parallel and patterned optogenetic manipulation of neurons in the brain slice using a DMD-based projector.

PubMed

Sakai, Seiichiro; Ueno, Kenichi; Ishizuka, Toru; Yawo, Hiromu

2013-01-01

Optical manipulation technologies greatly advanced the understanding of the neuronal network and its dysfunctions. To achieve patterned and parallel optical switching, we developed a microscopic illumination system using a commercial DMD-based projector and a software program. The spatiotemporal patterning of the system was evaluated using acute slices of the hippocampus. The neural activity was optically manipulated, positively by the combination of channelrhodopsin-2 (ChR2) and blue light, and negatively by the combination of archaerhodopsin-T (ArchT) and green light. It is suggested that our projector-managing optical system (PMOS) would effectively facilitate the optogenetic analyses of neurons and their circuits. Copyright © 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Design and test of a simulation system for autonomous optic-navigated planetary landing

NASA Astrophysics Data System (ADS)

Cai, Sheng; Yin, Yanhe; Liu, Yanjun; He, Fengyun

2018-02-01

In this paper, a simulation system based on commercial projector is proposed to test the optical navigation algorithms for autonomous planetary landing in laboratorial scenarios. The design work of optics, mechanics and synchronization control are carried out. Furthermore, the whole simulation system is set up and tested. Through the calibration of the system, two main problems, synchronization between the projector and CCD and pixel-level shifting caused by the low repeatability of DMD used in the projector, are settled. The experimental result shows that the RMS errors of pitch, yaw and roll angles are 0.78', 0.48', and 2.95' compared with the theoretical calculation, which can fulfill the requirement of experimental simulation for planetary landing in laboratory.

Fringe-shifting single-projector moiré topography application for cotyle implantate abrasion measurement

NASA Astrophysics Data System (ADS)

Rössler, Tomáš; Hrabovský, Miroslav; Pluháček, František

2005-08-01

The cotyle implantate is abraded in the body of patient and its shape changes. Information about the magnitude of abrasion is contained in the result contour map of the implantate. The locations and dimensions of abraded areas can be computed from the contours deformation. The method called the single-projector moire topography was used for the contour lines determination. The theoretical description of method is given at first. The design of the experimental set-up follows. The light grating projector was developed to realize the periodic structure on the measured surface. The method of fringe-shifting was carried out to increase the data quantity. The description of digital processing applied to the moire grating images is introduced at the end together with the examples of processed images.

The Principle of the Fermionic Projector: An Approach for Quantum Gravity?

NASA Astrophysics Data System (ADS)

Finster, Felix

In this short article we introduce the mathematical framework of the principle of the fermionic projector and set up a variational principle in discrete space-time. The underlying physical principles are discussed. We outline the connection to the continuum theory and state recent results. In the last two sections, we speculate on how it might be possible to describe quantum gravity within this framework.

Daylight coloring for monochrome infrared imagery

NASA Astrophysics Data System (ADS)

Gabura, James

2015-05-01

The effectiveness of infrared imagery in poor visibility situations is well established and the range of applications is expanding as we enter a new era of inexpensive thermal imagers for mobile phones. However there is a problem in that the counterintuitive reflectance characteristics of various common scene elements can cause slowed reaction times and impaired situational awareness-consequences that can be especially detrimental in emergency situations. While multiband infrared sensors can be used, they are inherently more costly. Here we propose a technique for adding a daylight color appearance to single band infrared images, using the normally overlooked property of local image texture. The simple method described here is illustrated with colorized images from the visible red and long wave infrared bands. Our colorizing process not only imparts a natural daylight appearance to infrared images but also enhances the contrast and visibility of otherwise obscure detail. We anticipate that this colorizing method will lead to a better user experience, faster reaction times and improved situational awareness for a growing community of infrared camera users. A natural extension of our process could expand upon its texture discerning feature by adding specialized filters for discriminating specific targets.

Clutter characterization within segmented hyperspectral imagery

NASA Astrophysics Data System (ADS)

Kacenjar, Steve T.; Hoffberg, Michael; North, Patrick

2007-10-01

Use of a Mean Class Propagation Model (MCPM) has been shown to be an effective approach in the expedient propagation of hyperspectral data scenes through the atmosphere. In this approach, real scene data are spatially subdivided into regions of common spectral properties. Each sub-region which we call a class possesses two important attributes (1) the mean spectral radiance and (2) the spectral covariance. The use of this attributes can significantly improve throughput performance of computing systems over conventional pixel-based methods. However, this approach assumes that background clutter can be approximated as having multivariate Gaussian distributions. Under such conditions, covariance propagations can be effectively performed from ground through the atmosphere. This paper explores this basic assumption using real-scene Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and examines how the partitioning of the scene into smaller and smaller segments influences local clutter characterization. It also presents a clutter characterization metric that helps explain the migration of the magnitude of statistical clutter from parent class to child sub-classes populations. It is shown that such a metric can be directly related to an approximate invariant between the parent class and its child classes.

Operation Desert Storm: Evaluation of the Air Campaign.

DTIC Science & Technology

1997-06-12

210Weight of Effort and TOE Platform Comparisons 217 Type of Effort Analysis Appendix IX 22RTreSesrRadar 221 Target Sensor Electro- optical 221 Technologies...DSMAC Digital Scene Matching Area Correlator ELE electrical facilities EO electro- optical EW electronic warfare FLIR forward-looking infrared FOV...the exposure of aircraft to clouds, haze, smoke, and high humidity, thereby impeding IR and electro- optical (EO) sensors and laser designators for

Generalized algebraic scene-based nonuniformity correction algorithm.

PubMed

Ratliff, Bradley M; Hayat, Majeed M; Tyo, J Scott

2005-02-01

A generalization of a recently developed algebraic scene-based nonuniformity correction algorithm for focal plane array (FPA) sensors is presented. The new technique uses pairs of image frames exhibiting arbitrary one- or two-dimensional translational motion to compute compensator quantities that are then used to remove nonuniformity in the bias of the FPA response. Unlike its predecessor, the generalization does not require the use of either a blackbody calibration target or a shutter. The algorithm has a low computational overhead, lending itself to real-time hardware implementation. The high-quality correction ability of this technique is demonstrated through application to real IR data from both cooled and uncooled infrared FPAs. A theoretical and experimental error analysis is performed to study the accuracy of the bias compensator estimates in the presence of two main sources of error.

Perturbative quantum field theory in the framework of the fermionic projector

NASA Astrophysics Data System (ADS)

Finster, Felix

2014-04-01

We give a microscopic derivation of perturbative quantum field theory, taking causal fermion systems and the framework of the fermionic projector as the starting point. The resulting quantum field theory agrees with standard quantum field theory on the tree level and reproduces all bosonic loop diagrams. The fermion loops are described in a different formalism in which no ultraviolet divergences occur.

Proceedings of the Eleventh International Symposium on Remote Sensing of Environment, volume 2. [application and processing of remotely sensed data

NASA Technical Reports Server (NTRS)

1977-01-01

Application and processing of remotely sensed data are discussed. Areas of application include: pollution monitoring, water quality, land use, marine resources, ocean surface properties, and agriculture. Image processing and scene analysis are described along with automated photointerpretation and classification techniques. Data from infrared and multispectral band scanners onboard LANDSAT satellites are emphasized.

Mars Rover Opportunity Panorama of Wharton Ridge Enhanced Color

NASA Image and Video Library

2016-10-07

This scene from NASA's Mars Exploration Rover Opportunity shows "Wharton Ridge," which forms part of the southern wall of "Marathon Valley" on the western rim of Endeavour Crater. In this version of the scene the landscape is presented in enhanced color to make differences in surface materials more easily visible The full extent of Wharton Ridge is visible, with the floor of Endeavour Crater beyond it and the far wall of the crater in the distant background. Near the right edge of the scene is "Lewis and Clark Gap," through which Opportunity crossed from Marathon Valley to "Bitterroot Valley" in September 2016. Before the rover departed Marathon Valley, its panoramic camera (Pancam) acquired the component images for this scene on Aug. 30, 2016, during the 4,480th Martian day, or sol, of Opportunity's work on Mars. Opportunity's science team chose the ridge's name to honor the memory of Robert A. Wharton (1951-2012), an astrobiologist who was a pioneer in the use of terrestrial analog environments, particularly in Antarctica, to study scientific problems connected to the habitability of Mars. Over the course of his career, he was a visiting senior scientist at NASA Headquarters, vice president for research at the Desert Research Institute, provost at Idaho State University, and president of the South Dakota School of Mines and Technology. The view spans from east-northeast at left to southeast at right. Color in the scene comes from component images taken through three of the Pancam's color filters, centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet). http://photojournal.jpl.nasa.gov/catalog/PIA20850

System for training and evaluation of security personnel in use of firearms

DOEpatents

Hall, Howard F.

1990-01-01

An interactive video display system comprising a laser disc player with a remote large-screen projector to view life-size video scenarios and a control computer. A video disc has at least one basic scenario and one or more branches of the basic scenario with one or more subbranches from any one or more of the branches and further subbranches, if desired, to any level of programming desired. The control computer is programmed for interactive control of the branching, and control of other effects that enhance the scenario, in response to detection of when the trainee has (1) drawn an infrared laser handgun from his holster, (2) fired his laser handgun, (3) taken cover, (4) advanced or retreated from the adversary on the screen, and (5) when the adversary has fired his gun at the trainee.

The Fermionic Projector, entanglement and the collapse of the wave function

NASA Astrophysics Data System (ADS)

Finster, Felix

2011-07-01

After a brief introduction to the fermionic projector approach, we review how entanglement and second quantized bosonic and fermionic fields can be described in this framework. The constructions are discussed with regard to decoherence phenomena and the measurement problem. We propose a mechanism leading to the collapse of the wave function in the quantum mechanical measurement process.

Spectral decomposition of AVIRIS data

NASA Technical Reports Server (NTRS)

Gaddis, Lisa; Soderblom, Laurence; Kieffer, Hugh; Becker, Kris; Torson, Jim; Mullins, Kevin

1993-01-01

A set of techniques is presented that uses only information contained within a raw Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) scene to estimate and to remove additive components such as multiple scattering and instrument dark current. Multiplicative components (instrument gain, topographic modulation of brightness, atmospheric transmission) can then be normalized, permitting enhancement, extraction, and identification of relative reflectance information related to surface composition and mineralogy. The technique for derivation of additive-component spectra from a raw AVIRIS scene is an adaption of the 'regression intersection method' of Crippen. This method uses two surface units that are spatially extensive, and located in rugged terrain. For a given wavelength pair, subtraction of the derived additive component from individual band values will remove topography in both regions in a band/band ratio image. Normalization of all spectra in the scene to the average scene spectrum then results in cancellation of multiplicative components and production of a relative-reflectance scene. The resulting AVIRIS product contains relative-reflectance features due to mineral absorption that depart from the average spectrum. These features commonly are extremely weak and difficult to recognize, but they can be enhanced by using two simple 3-D image-processing tools. The validity of these techniques will be demonstrated by comparisons between relative-reflectance AVIRIS spectra and those derived by using JPL standard calibrations. The AVIRIS data used in this analysis were acquired over the Kelso Dunes area (34 deg 55' N, 115 deg 43' W) of the eastern Mojave Desert, CA (in 1987) and the Upheaval Dome area (38 deg 27' N, 109 deg 55' W) of the Canyonlands National Park, UT (in 1991).

System for training and evaluation of security personnel in use of firearms

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

Hall, H.F.

This patent describes an interactive video display system comprising a laser disc player with a remote large-screen projector to view life-size video scenarios and a control computer. A video disc has at least one basic scenario and one or more branches of the basic scenario with one or more subbranches from any one or more of the branches and further subbranches, if desired, to any level of programming desired. The control computer is programmed for interactive control of the branching, and control of other effects that enhance the scenario, in response to detection of when the trainee has drawn anmore » infrared laser handgun from his holster, fired his laser handgun, taken cover, advanced or retreated from the adversary on the screen, and when the adversary has fired his gun at the trainee.« less

Research on hyperspectral dynamic scene and image sequence simulation

NASA Astrophysics Data System (ADS)

Sun, Dandan; Liu, Fang; Gao, Jiaobo; Sun, Kefeng; Hu, Yu; Li, Yu; Xie, Junhu; Zhang, Lei

2016-10-01

This paper presents a simulation method of hyperspectral dynamic scene and image sequence for hyperspectral equipment evaluation and target detection algorithm. Because of high spectral resolution, strong band continuity, anti-interference and other advantages, in recent years, hyperspectral imaging technology has been rapidly developed and is widely used in many areas such as optoelectronic target detection, military defense and remote sensing systems. Digital imaging simulation, as a crucial part of hardware in loop simulation, can be applied to testing and evaluation hyperspectral imaging equipment with lower development cost and shorter development period. Meanwhile, visual simulation can produce a lot of original image data under various conditions for hyperspectral image feature extraction and classification algorithm. Based on radiation physic model and material characteristic parameters this paper proposes a generation method of digital scene. By building multiple sensor models under different bands and different bandwidths, hyperspectral scenes in visible, MWIR, LWIR band, with spectral resolution 0.01μm, 0.05μm and 0.1μm have been simulated in this paper. The final dynamic scenes have high real-time and realistic, with frequency up to 100 HZ. By means of saving all the scene gray data in the same viewpoint image sequence is obtained. The analysis results show whether in the infrared band or the visible band, the grayscale variations of simulated hyperspectral images are consistent with the theoretical analysis results.

Projection Mapping User Interface for Disabled People

PubMed Central

Simutis, Rimvydas; Maskeliūnas, Rytis

2018-01-01

Difficulty in communicating is one of the key challenges for people suffering from severe motor and speech disabilities. Often such person can communicate and interact with the environment only using assistive technologies. This paper presents a multifunctional user interface designed to improve communication efficiency and person independence. The main component of this interface is a projection mapping technique used to highlight objects in the environment. Projection mapping makes it possible to create a natural augmented reality information presentation method. The user interface combines a depth sensor and a projector to create camera-projector system. We provide a detailed description of camera-projector system calibration procedure. The described system performs tabletop object detection and automatic projection mapping. Multiple user input modalities have been integrated into the multifunctional user interface. Such system can be adapted to the needs of people with various disabilities. PMID:29686827

Feasibility study of utilizing ultraportable projectors for endoscopic video display (with videos).

PubMed

Tang, Shou-Jiang; Fehring, Amanda; Mclemore, Mac; Griswold, Michael; Wang, Wanmei; Paine, Elizabeth R; Wu, Ruonan; To, Filip

2014-10-01

Modern endoscopy requires video display. Recent miniaturized, ultraportable projectors are affordable, durable, and offer quality image display. Explore feasibility of using ultraportable projectors in endoscopy. Prospective bench-top comparison; clinical feasibility study. Masked comparison study of images displayed via 2 Samsung ultraportable light-emitting diode projectors (pocket-sized SP-HO3; pico projector SP-P410M) and 1 Microvision Showwx-II Laser pico projector. BENCH-TOP FEASIBILITY STUDY: Prerecorded endoscopic video was streamed via computer. CLINICAL COMPARISON STUDY: Live high-definition endoscopy video was simultaneously displayed through each processor onto a standard liquid crystal display monitor and projected onto a portable, pull-down projection screen. Endoscopists, endoscopy nurses, and technicians rated video images; ratings were analyzed by linear mixed-effects regression models with random intercepts. All projectors were easy to set up, adjust, focus, and operate, with no real-time lapse for any. Bench-top study outcomes: Samsung pico preferred to Laser pico, overall rating 1.5 units higher (95% confidence interval [CI] = 0.7-2.4), P < .001; Samsung pocket preferred to Laser pico, 3.3 units higher (95% CI = 2.4-4.1), P < .001; Samsung pocket preferred to Samsung pico, 1.7 units higher (95% CI = 0.9-2.5), P < .001. The clinical comparison study confirmed the Samsung pocket projector as best, with a higher overall rating of 2.3 units (95% CI = 1.6-3.0), P < .001, than Samsung pico. Low brightness currently limits pico projector use in clinical endoscopy. The pocket projector, with higher brightness levels (170 lumens), is clinically useful. Continued improvements to ultraportable projectors will supply a needed niche in endoscopy through portability, reduced cost, and equal or better image quality. © The Author(s) 2013.

A robust sub-pixel edge detection method of infrared image based on tremor-based retinal receptive field model

NASA Astrophysics Data System (ADS)

Gao, Kun; Yang, Hu; Chen, Xiaomei; Ni, Guoqiang

2008-03-01

Because of complex thermal objects in an infrared image, the prevalent image edge detection operators are often suitable for a certain scene and extract too wide edges sometimes. From a biological point of view, the image edge detection operators work reliably when assuming a convolution-based receptive field architecture. A DoG (Difference-of- Gaussians) model filter based on ON-center retinal ganglion cell receptive field architecture with artificial eye tremors introduced is proposed for the image contour detection. Aiming at the blurred edges of an infrared image, the subsequent orthogonal polynomial interpolation and sub-pixel level edge detection in rough edge pixel neighborhood is adopted to locate the foregoing rough edges in sub-pixel level. Numerical simulations show that this method can locate the target edge accurately and robustly.

Research on hyperspectral dynamic scene and image sequence simulation

NASA Astrophysics Data System (ADS)

Sun, Dandan; Gao, Jiaobo; Sun, Kefeng; Hu, Yu; Li, Yu; Xie, Junhu; Zhang, Lei

2016-10-01

This paper presents a simulation method of hyper-spectral dynamic scene and image sequence for hyper-spectral equipment evaluation and target detection algorithm. Because of high spectral resolution, strong band continuity, anti-interference and other advantages, in recent years, hyper-spectral imaging technology has been rapidly developed and is widely used in many areas such as optoelectronic target detection, military defense and remote sensing systems. Digital imaging simulation, as a crucial part of hardware in loop simulation, can be applied to testing and evaluation hyper-spectral imaging equipment with lower development cost and shorter development period. Meanwhile, visual simulation can produce a lot of original image data under various conditions for hyper-spectral image feature extraction and classification algorithm. Based on radiation physic model and material characteristic parameters this paper proposes a generation method of digital scene. By building multiple sensor models under different bands and different bandwidths, hyper-spectral scenes in visible, MWIR, LWIR band, with spectral resolution 0.01μm, 0.05μm and 0.1μm have been simulated in this paper. The final dynamic scenes have high real-time and realistic, with frequency up to 100 HZ. By means of saving all the scene gray data in the same viewpoint image sequence is obtained. The analysis results show whether in the infrared band or the visible band, the grayscale variations of simulated hyper-spectral images are consistent with the theoretical analysis results.

Integration of an open interface PC scene generator using COTS DVI converter hardware

NASA Astrophysics Data System (ADS)

Nordland, Todd; Lyles, Patrick; Schultz, Bret

2006-05-01

Commercial-Off-The-Shelf (COTS) personal computer (PC) hardware is increasingly capable of computing high dynamic range (HDR) scenes for military sensor testing at high frame rates. New electro-optical and infrared (EO/IR) scene projectors feature electrical interfaces that can accept the DVI output of these PC systems. However, military Hardware-in-the-loop (HWIL) facilities such as those at the US Army Aviation and Missile Research Development and Engineering Center (AMRDEC) utilize a sizeable inventory of existing projection systems that were designed to use the Silicon Graphics Incorporated (SGI) digital video port (DVP, also known as DVP2 or DD02) interface. To mate the new DVI-based scene generation systems to these legacy projection systems, CG2 Inc., a Quantum3D Company (CG2), has developed a DVI-to-DVP converter called Delta DVP. This device takes progressive scan DVI input, converts it to digital parallel data, and combines and routes color components to derive a 16-bit wide luminance channel replicated on a DVP output interface. The HWIL Functional Area of AMRDEC has developed a suite of modular software to perform deterministic real-time, wave band-specific rendering of sensor scenes, leveraging the features of commodity graphics hardware and open source software. Together, these technologies enable sensor simulation and test facilities to integrate scene generation and projection components with diverse pedigrees.

Development of infrared scene projectors for testing fire-fighter cameras

NASA Astrophysics Data System (ADS)

Neira, Jorge E.; Rice, Joseph P.; Amon, Francine K.

2008-04-01

We have developed two types of infrared scene projectors for hardware-in-the-loop testing of thermal imaging cameras such as those used by fire-fighters. In one, direct projection, images are projected directly into the camera. In the other, indirect projection, images are projected onto a diffuse screen, which is then viewed by the camera. Both projectors use a digital micromirror array as the spatial light modulator, in the form of a Micromirror Array Projection System (MAPS) engine having resolution of 800 x 600 with mirrors on a 17 micrometer pitch, aluminum-coated mirrors, and a ZnSe protective window. Fire-fighter cameras are often based upon uncooled microbolometer arrays and typically have resolutions of 320 x 240 or lower. For direct projection, we use an argon-arc source, which provides spectral radiance equivalent to a 10,000 Kelvin blackbody over the 7 micrometer to 14 micrometer wavelength range, to illuminate the micromirror array. For indirect projection, an expanded 4 watt CO II laser beam at a wavelength of 10.6 micrometers illuminates the micromirror array and the scene formed by the first-order diffracted light from the array is projected onto a diffuse aluminum screen. In both projectors, a well-calibrated reference camera is used to provide non-uniformity correction and brightness calibration of the projected scenes, and the fire-fighter cameras alternately view the same scenes. In this paper, we compare the two methods for this application and report on our quantitative results. Indirect projection has an advantage of being able to more easily fill the wide field of view of the fire-fighter cameras, which typically is about 50 degrees. Direct projection more efficiently utilizes the available light, which will become important in emerging multispectral and hyperspectral applications.

Augmented reality and dynamic infrared thermography for perforator mapping in the anterolateral thigh.

PubMed

Cifuentes, Ignacio Javier; Dagnino, Bruno Leonardo; Salisbury, María Carolina; Perez, María Eliana; Ortega, Claudia; Maldonado, Daniela

2018-05-01

Dynamic infrared thermography (DIRT) has been used for the preoperative mapping of cutaneous perforators. This technique has shown a positive correlation with intraoperative findings. Our aim was to evaluate the accuracy of perforator mapping with DIRT and augmented reality using a portable projector. For this purpose, three volunteers had both of their anterolateral thighs assessed for the presence and location of cutaneous perforators using DIRT. The obtained image of these "hotspots" was projected back onto the thigh and the presence of Doppler signals within a 10-cm diameter from the midpoint between the lateral patella and the anterior superior iliac spine was assessed using a handheld Doppler device. Hotspots were identified in all six anterolateral thighs and were successfully projected onto the skin. The median number of perforators identified within the area of interest was 5 (range, 3-8) and the median time needed to identify them was 3.5 minutes (range, 3.3-4.0 minutes). Every hotspot was correlated to a Doppler sound signal. In conclusion, augmented reality can be a reliable method for transferring the location of perforators identified by DIRT onto the thigh, facilitating its assessment and yielding a reliable map of potential perforators for flap raising.

Augmented reality and dynamic infrared thermography for perforator mapping in the anterolateral thigh

PubMed Central

Cifuentes, Ignacio Javier; Dagnino, Bruno Leonardo; Salisbury, María Carolina; Perez, María Eliana; Ortega, Claudia; Maldonado, Daniela

2018-01-01

Dynamic infrared thermography (DIRT) has been used for the preoperative mapping of cutaneous perforators. This technique has shown a positive correlation with intraoperative findings. Our aim was to evaluate the accuracy of perforator mapping with DIRT and augmented reality using a portable projector. For this purpose, three volunteers had both of their anterolateral thighs assessed for the presence and location of cutaneous perforators using DIRT. The obtained image of these “hotspots” was projected back onto the thigh and the presence of Doppler signals within a 10-cm diameter from the midpoint between the lateral patella and the anterior superior iliac spine was assessed using a handheld Doppler device. Hotspots were identified in all six anterolateral thighs and were successfully projected onto the skin. The median number of perforators identified within the area of interest was 5 (range, 3–8) and the median time needed to identify them was 3.5 minutes (range, 3.3–4.0 minutes). Every hotspot was correlated to a Doppler sound signal. In conclusion, augmented reality can be a reliable method for transferring the location of perforators identified by DIRT onto the thigh, facilitating its assessment and yielding a reliable map of potential perforators for flap raising. PMID:29788686

System for training and evaluation of security personnel in use of firearms

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

Hall, H.F.

An interactive video display system comprising a laser disc player with a remote large-screen projector to view life-size video scenarios and a control computer. A video disc has at least one basic scenario and one or more branches of the basic scenario with one or more subbranches from any one or more of the branches and further subbranches, if desired, to any level of programming desired. The control computer is programmed for interactive control of the branching, and control of other effects that enhance the scenario, in response to detection of when the trainee has drawn an infrared laser handgunmore » from high holster, fired his laser handgun, taken cover, advanced or retreated from the adversary on the screen, and when the adversary has fired his gun at the trainee. 8 figs.« less

Tower testing of a 64W shortwave infrared supercontinuum laser for use as a hyperspectral imaging illuminator

NASA Astrophysics Data System (ADS)

Meola, Joseph; Absi, Anthony; Islam, Mohammed N.; Peterson, Lauren M.; Ke, Kevin; Freeman, Michael J.; Ifaraguerri, Agustin I.

2014-06-01

Hyperspectral imaging systems are currently used for numerous activities related to spectral identification of materials. These passive imaging systems rely on naturally reflected/emitted radiation as the source of the signal. Thermal infrared systems measure radiation emitted from objects in the scene. As such, they can operate at both day and night. However, visible through shortwave infrared systems measure solar illumination reflected from objects. As a result, their use is limited to daytime applications. Omni Sciences has produced high powered broadband shortwave infrared super-continuum laser illuminators. A 64-watt breadboard system was recently packaged and tested at Wright-Patterson Air Force Base to gauge beam quality and to serve as a proof-of-concept for potential use as an illuminator for a hyperspectral receiver. The laser illuminator was placed in a tower and directed along a 1.4km slant path to various target materials with reflected radiation measured with both a broadband camera and a hyperspectral imaging system to gauge performance.

A color fusion method of infrared and low-light-level images based on visual perception

NASA Astrophysics Data System (ADS)

Han, Jing; Yan, Minmin; Zhang, Yi; Bai, Lianfa

2014-11-01

The color fusion images can be obtained through the fusion of infrared and low-light-level images, which will contain both the information of the two. The fusion images can help observers to understand the multichannel images comprehensively. However, simple fusion may lose the target information due to inconspicuous targets in long-distance infrared and low-light-level images; and if targets extraction is adopted blindly, the perception of the scene information will be affected seriously. To solve this problem, a new fusion method based on visual perception is proposed in this paper. The extraction of the visual targets ("what" information) and parallel processing mechanism are applied in traditional color fusion methods. The infrared and low-light-level color fusion images are achieved based on efficient typical targets learning. Experimental results show the effectiveness of the proposed method. The fusion images achieved by our algorithm can not only improve the detection rate of targets, but also get rich natural information of the scenes.

The application of color display techniques for the analysis of Nimbus infrared radiation data

NASA Technical Reports Server (NTRS)

Allison, L. J.; Cherrix, G. T.; Ausfresser, H.

1972-01-01

A color enhancement system designed for the Applications Technology Satellite (ATS) spin scan experiment has been adapted for the analysis of Nimbus infrared radiation measurements. For a given scene recorded on magnetic tape by the Nimbus scanning radiometers, a virtually unlimited number of color images can be produced at the ATS Operations Control Center from a color selector paper tape input. Linear image interpolation has produced radiation analyses in which each brightness-color interval has a smooth boundary without any mosaic effects. An annotated latitude-longitude gridding program makes it possible to precisely locate geophysical parameters, which permits accurate interpretation of pertinent meteorological, geological, hydrological, and oceanographic features.

Center for Coastline Security Technology, Year 3

DTIC Science & Technology

2008-05-01

Polarization control for 3D Imaging with the Sony SRX-R105 Digital Cinema Projectors 3.4 HDMAX Camera and Sony SRX-R105 Projector Configuration for 3D...HDMAX Camera Pair Figure 3.2 Sony SRX-R105 Digital Cinema Projector Figure 3.3 Effect of camera rotation on projected overlay image. Figure 3.4...system that combines a pair of FAU’s HD-MAX video cameras with a pair of Sony SRX-R105 digital cinema projectors for stereo imaging and projection

ASTER Mexicali

NASA Image and Video Library

2000-10-06

Dramatic differences in land use patterns are highlighted in this image of the U.S.-Mexico border. Lush, regularly gridded agricultural fields on the U.S. side contrast with the more barren fields of Mexico. This June 12, 2000, sub-scene combines visible and near infrared bands, displaying vegetation in red. The town of Mexicali-Calexico spans the border in the middle of the image; El Centro, California, is in the upper left. Watered by canals fed from the Colorado River, California's Imperial Valley is one of the country's major fruit and vegetable producers. This image covers an area 24 kilometers (15 miles) wide and 30 kilometers (19 miles) long in three bands of the reflected visible and infrared wavelength region. http://photojournal.jpl.nasa.gov/catalog/PIA02659

Recursive algorithms for bias and gain nonuniformity correction in infrared videos.

PubMed

Pipa, Daniel R; da Silva, Eduardo A B; Pagliari, Carla L; Diniz, Paulo S R

2012-12-01

Infrared focal-plane array (IRFPA) detectors suffer from fixed-pattern noise (FPN) that degrades image quality, which is also known as spatial nonuniformity. FPN is still a serious problem, despite recent advances in IRFPA technology. This paper proposes new scene-based correction algorithms for continuous compensation of bias and gain nonuniformity in FPA sensors. The proposed schemes use recursive least-square and affine projection techniques that jointly compensate for both the bias and gain of each image pixel, presenting rapid convergence and robustness to noise. The synthetic and real IRFPA videos experimentally show that the proposed solutions are competitive with the state-of-the-art in FPN reduction, by presenting recovered images with higher fidelity.

Principle component analyses of questionnaires measuring individual differences in synaesthetic phenomenology.

PubMed

Anderson, Hazel P; Ward, Jamie

2015-05-01

Questionnaires have been developed for categorising grapheme-colour synaesthetes into two sub-types based on phenomenology: associators and projectors. The general approach has been to assume a priori the existence of two sub-types on a single dimension (with endpoints as projector and associator) rather than explore, in a data-driven fashion, other possible models. We collected responses from 175 grapheme-colour synaesthetes on two questionnaires, the Illustrated Synaesthetic Experience Questionnaire (Skelton, Ludwig, & Mohr, 2009) and Rouw and Scholte's (2007) Projector-Associator Questionnaire. After Principle Component Analysis both questionnaires were comprised of two factors which coincide with the projector/associator distinction. This suggests that projectors and associators are not opposites of each other, but separate dimensions of experience (e.g. some synaesthetes claim to be both, others claim to be neither). The revised questionnaires provide a useful tool for researchers and insights into the phenomenology of synaesthesia. Copyright © 2015 Elsevier Inc. All rights reserved.

[Authentication of Trace Material Evidence in Forensic Science Field with Infrared Microscopic Technique].

PubMed

Jiang, Zhi-quan; Hu, Ke-liang

2016-03-01

In the field of forensic science, conventional infrared spectral analysis technique is usually unable to meet the detection requirements, because only very a few trace material evidence with diverse shapes and complex compositions, can be extracted from the crime scene. Infrared microscopic technique is developed based on a combination of Fourier-transform infrared spectroscopic technique and microscopic technique. Infrared microscopic technique has a lot of advantages over conventional infrared spectroscopic technique, such as high detection sensitivity, micro-area analysisand nondestructive examination. It has effectively solved the problem of authentication of trace material evidence in the field of forensic science. Additionally, almost no external interference is introduced during measurements by infrared microscopic technique. It can satisfy the special need that the trace material evidence must be reserved for witness in court. It is illustrated in detail through real case analysis in this experimental center that, infrared microscopic technique has advantages in authentication of trace material evidence in forensic science field. In this paper, the vibration features in infrared spectra of material evidences, including paints, plastics, rubbers, fibers, drugs and toxicants, can be comparatively analyzed by means of infrared microscopic technique, in an attempt to provide powerful spectroscopic evidence for qualitative diagnosis of various criminal and traffic accident cases. The experimental results clearly suggest that infrared microscopic technique has an incomparable advantage and it has become an effective method for authentication of trace material evidence in the field of forensic science.

Airborne Infrared and Visible Image Fusion Combined with Region Segmentation.

PubMed

Zuo, Yujia; Liu, Jinghong; Bai, Guanbing; Wang, Xuan; Sun, Mingchao

2017-05-15

This paper proposes an infrared (IR) and visible image fusion method introducing region segmentation into the dual-tree complex wavelet transform (DTCWT) region. This method should effectively improve both the target indication and scene spectrum features of fusion images, and the target identification and tracking reliability of fusion system, on an airborne photoelectric platform. The method involves segmenting the region in an IR image by significance, and identifying the target region and the background region; then, fusing the low-frequency components in the DTCWT region according to the region segmentation result. For high-frequency components, the region weights need to be assigned by the information richness of region details to conduct fusion based on both weights and adaptive phases, and then introducing a shrinkage function to suppress noise; Finally, the fused low-frequency and high-frequency components are reconstructed to obtain the fusion image. The experimental results show that the proposed method can fully extract complementary information from the source images to obtain a fusion image with good target indication and rich information on scene details. They also give a fusion result superior to existing popular fusion methods, based on eithers subjective or objective evaluation. With good stability and high fusion accuracy, this method can meet the fusion requirements of IR-visible image fusion systems.

Airborne Infrared and Visible Image Fusion Combined with Region Segmentation

PubMed Central

Zuo, Yujia; Liu, Jinghong; Bai, Guanbing; Wang, Xuan; Sun, Mingchao

2017-01-01

This paper proposes an infrared (IR) and visible image fusion method introducing region segmentation into the dual-tree complex wavelet transform (DTCWT) region. This method should effectively improve both the target indication and scene spectrum features of fusion images, and the target identification and tracking reliability of fusion system, on an airborne photoelectric platform. The method involves segmenting the region in an IR image by significance, and identifying the target region and the background region; then, fusing the low-frequency components in the DTCWT region according to the region segmentation result. For high-frequency components, the region weights need to be assigned by the information richness of region details to conduct fusion based on both weights and adaptive phases, and then introducing a shrinkage function to suppress noise; Finally, the fused low-frequency and high-frequency components are reconstructed to obtain the fusion image. The experimental results show that the proposed method can fully extract complementary information from the source images to obtain a fusion image with good target indication and rich information on scene details. They also give a fusion result superior to existing popular fusion methods, based on eithers subjective or objective evaluation. With good stability and high fusion accuracy, this method can meet the fusion requirements of IR-visible image fusion systems. PMID:28505137

Identification, definition and mapping of terrestrial ecosystems in interior Alaska

NASA Technical Reports Server (NTRS)

Anderson, J. H. (Principal Investigator)

1973-01-01

The author has identified the following significant results. A reconstituted, simulated color-infrared print, enlarged to a scale of 1:250,000, was used to make a vegetation map of a 3,110 sq km area just west of Fairbanks, Alaska. Information was traced from the print which comprised the southeastern part of ERTS-1 scene 1033-21011. A 1:1,000,000 scale color-infrared transparency of this scene, obtained from NASA, was used along side the print as an aid in recognizing colors, color intensities and blends, and mosaics of different colors. Color units on the transparency and print were identified according to vegetation types using NASA air photos, U.S. Forest Service air photos, and experience of the investigator. Five more or less pure colors were identified and associated with vegetation types. These colors were designated according to their appearances on the print: (1) orange for forest vegetation dominated by broad-leaved trees: (2) gray for forest vegetation dominated by needle-leaved trees; (3) violet for scrub vegetation; (4) light violet denoting herbaceous tundra vegetation; and (5) dull violet for muskeg vegetation. This study has shown, through close examinations of the NASA transparency, that much more detailed vegetation landscape, or ecosystem maps could be produced, if only spectral signatures could be consistently and reliably recognized and transferred to a map of suitable scale.

Nighttime Foreground Pedestrian Detection Based on Three-Dimensional Voxel Surface Model.

PubMed

Li, Jing; Zhang, Fangbing; Wei, Lisong; Yang, Tao; Lu, Zhaoyang

2017-10-16

Pedestrian detection is among the most frequently-used preprocessing tasks in many surveillance application fields, from low-level people counting to high-level scene understanding. Even though many approaches perform well in the daytime with sufficient illumination, pedestrian detection at night is still a critical and challenging problem for video surveillance systems. To respond to this need, in this paper, we provide an affordable solution with a near-infrared stereo network camera, as well as a novel three-dimensional foreground pedestrian detection model. Specifically, instead of using an expensive thermal camera, we build a near-infrared stereo vision system with two calibrated network cameras and near-infrared lamps. The core of the system is a novel voxel surface model, which is able to estimate the dynamic changes of three-dimensional geometric information of the surveillance scene and to segment and locate foreground pedestrians in real time. A free update policy for unknown points is designed for model updating, and the extracted shadow of the pedestrian is adopted to remove foreground false alarms. To evaluate the performance of the proposed model, the system is deployed in several nighttime surveillance scenes. Experimental results demonstrate that our method is capable of nighttime pedestrian segmentation and detection in real time under heavy occlusion. In addition, the qualitative and quantitative comparison results show that our work outperforms classical background subtraction approaches and a recent RGB-D method, as well as achieving comparable performance with the state-of-the-art deep learning pedestrian detection method even with a much lower hardware cost.

Nighttime Foreground Pedestrian Detection Based on Three-Dimensional Voxel Surface Model

PubMed Central

Li, Jing; Zhang, Fangbing; Wei, Lisong; Lu, Zhaoyang

2017-01-01

Pedestrian detection is among the most frequently-used preprocessing tasks in many surveillance application fields, from low-level people counting to high-level scene understanding. Even though many approaches perform well in the daytime with sufficient illumination, pedestrian detection at night is still a critical and challenging problem for video surveillance systems. To respond to this need, in this paper, we provide an affordable solution with a near-infrared stereo network camera, as well as a novel three-dimensional foreground pedestrian detection model. Specifically, instead of using an expensive thermal camera, we build a near-infrared stereo vision system with two calibrated network cameras and near-infrared lamps. The core of the system is a novel voxel surface model, which is able to estimate the dynamic changes of three-dimensional geometric information of the surveillance scene and to segment and locate foreground pedestrians in real time. A free update policy for unknown points is designed for model updating, and the extracted shadow of the pedestrian is adopted to remove foreground false alarms. To evaluate the performance of the proposed model, the system is deployed in several nighttime surveillance scenes. Experimental results demonstrate that our method is capable of nighttime pedestrian segmentation and detection in real time under heavy occlusion. In addition, the qualitative and quantitative comparison results show that our work outperforms classical background subtraction approaches and a recent RGB-D method, as well as achieving comparable performance with the state-of-the-art deep learning pedestrian detection method even with a much lower hardware cost. PMID:29035295

Evaluation and display of polarimetric image data using long-wave cooled microgrid focal plane arrays

NASA Astrophysics Data System (ADS)

Bowers, David L.; Boger, James K.; Wellems, L. David; Black, Wiley T.; Ortega, Steve E.; Ratliff, Bradley M.; Fetrow, Matthew P.; Hubbs, John E.; Tyo, J. Scott

2006-05-01

Recent developments for Long Wave InfraRed (LWIR) imaging polarimeters include incorporating a microgrid polarizer array onto the focal plane array (FPA). Inherent advantages over typical polarimeters include packaging and instantaneous acquisition of thermal and polarimetric information. This allows for real time video of thermal and polarimetric products. The microgrid approach has inherent polarization measurement error due to the spatial sampling of a non-uniform scene, residual pixel to pixel variations in the gain corrected responsivity and in the noise equivalent input (NEI), and variations in the pixel to pixel micro-polarizer performance. The Degree of Linear Polarization (DoLP) is highly sensitive to these parameters and is consequently used as a metric to explore instrument sensitivities. Image processing and fusion techniques are used to take advantage of the inherent thermal and polarimetric sensing capability of this FPA, providing additional scene information in real time. Optimal operating conditions are employed to improve FPA uniformity and sensitivity. Data from two DRS Infrared Technologies, L.P. (DRS) microgrid polarizer HgCdTe FPAs are presented. One FPA resides in a liquid nitrogen (LN2) pour filled dewar with a 80°K nominal operating temperature. The other FPA resides in a cryogenic (cryo) dewar with a 60° K nominal operating temperature.

Three-dimensional shape measurement and calibration for fringe projection by considering unequal height of the projector and the camera

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

Zhu Feipeng; Shi Hongjian; Bai Pengxiang

In fringe projection, the CCD camera and the projector are often placed at equal height. In this paper, we will study the calibration of an unequal arrangement of the CCD camera and the projector. The principle of fringe projection with two-dimensional digital image correlation to acquire the profile of object surface is described in detail. By formula derivation and experiment, the linear relationship between the out-of-plane calibration coefficient and the y coordinate is clearly found. To acquire the three-dimensional (3D) information of an object correctly, this paper presents an effective calibration method with linear least-squares fitting, which is very simplemore » in principle and calibration. Experiments are implemented to validate the availability and reliability of the calibration method.« less

Projection Mapping User Interface for Disabled People.

PubMed

Gelšvartas, Julius; Simutis, Rimvydas; Maskeliūnas, Rytis

2018-01-01

Difficulty in communicating is one of the key challenges for people suffering from severe motor and speech disabilities. Often such person can communicate and interact with the environment only using assistive technologies. This paper presents a multifunctional user interface designed to improve communication efficiency and person independence. The main component of this interface is a projection mapping technique used to highlight objects in the environment. Projection mapping makes it possible to create a natural augmented reality information presentation method. The user interface combines a depth sensor and a projector to create camera-projector system. We provide a detailed description of camera-projector system calibration procedure. The described system performs tabletop object detection and automatic projection mapping. Multiple user input modalities have been integrated into the multifunctional user interface. Such system can be adapted to the needs of people with various disabilities.

Design of LED projector based on gradient-index lens

NASA Astrophysics Data System (ADS)

Qian, Liyong; Zhu, Xiangbing; Cui, Haitian; Wang, Yuanhang

2018-01-01

In this study, a new type of projector light path is designed to eliminate the deficits of existing projection systems, such as complex structure and low collection efficiency. Using a three-color LED array as the lighting source, by means of the special optical properties of a gradient-index lens, the complex structure of the traditional projector is simplified. Traditional components, such as the color wheel, relay lens, and mirror, become unnecessary. In this way, traditional problems, such as low utilization of light energy and loss of light energy, are solved. With the help of Zemax software, the projection lens is optimized. The optimized projection lens, LED, gradient-index lens, and digital micromirror device are imported into Tracepro. The ray tracing results show that both the utilization of light energy and the uniformity are improved significantly.

GPU-accelerated iterative reconstruction from Compton scattered data using a matched pair of conic projector and backprojector.

PubMed

Nguyen, Van-Giang; Lee, Soo-Jin

2016-07-01

Iterative reconstruction from Compton scattered data is known to be computationally more challenging than that from conventional line-projection based emission data in that the gamma rays that undergo Compton scattering are modeled as conic projections rather than line projections. In conventional tomographic reconstruction, to parallelize the projection and backprojection operations using the graphics processing unit (GPU), approximated methods that use an unmatched pair of ray-tracing forward projector and voxel-driven backprojector have been widely used. In this work, we propose a new GPU-accelerated method for Compton camera reconstruction which is more accurate by using exactly matched pair of projector and backprojector. To calculate conic forward projection, we first sample the cone surface into conic rays and accumulate the intersecting chord lengths of the conic rays passing through voxels using a fast ray-tracing method (RTM). For conic backprojection, to obtain the true adjoint of the conic forward projection, while retaining the computational efficiency of the GPU, we use a voxel-driven RTM which is essentially the same as the standard RTM used for the conic forward projector. Our simulation results show that, while the new method is about 3 times slower than the approximated method, it is still about 16 times faster than the CPU-based method without any loss of accuracy. The net conclusion is that our proposed method is guaranteed to retain the reconstruction accuracy regardless of the number of iterations by providing a perfectly matched projector-backprojector pair, which makes iterative reconstruction methods for Compton imaging faster and more accurate. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A fusion algorithm for infrared and visible based on guided filtering and phase congruency in NSST domain

NASA Astrophysics Data System (ADS)

Liu, Zhanwen; Feng, Yan; Chen, Hang; Jiao, Licheng

2017-10-01

A novel and effective image fusion method is proposed for creating a highly informative and smooth surface of fused image through merging visible and infrared images. Firstly, a two-scale non-subsampled shearlet transform (NSST) is employed to decompose the visible and infrared images into detail layers and one base layer. Then, phase congruency is adopted to extract the saliency maps from the detail layers and a guided filtering is proposed to compute the filtering output of base layer and saliency maps. Next, a novel weighted average technique is used to make full use of scene consistency for fusion and obtaining coefficients map. Finally the fusion image was acquired by taking inverse NSST of the fused coefficients map. Experiments show that the proposed approach can achieve better performance than other methods in terms of subjective visual effect and objective assessment.

ASTER's First Views of Red Sea, Ethiopia - Thermal-Infrared (TIR) Image (monochrome)

NASA Technical Reports Server (NTRS)

2000-01-01

ASTER succeeded in acquiring this image at night, which is something Visible/Near Infrared VNIR) and Shortwave Infrared (SWIR) sensors cannot do. The scene covers the Red Sea coastline to an inland area of Ethiopia. White pixels represent areas with higher temperature material on the surface, while dark pixels indicate lower temperatures. This image shows ASTER's ability as a highly sensitive, temperature-discerning instrument and the first spaceborne TIR multi-band sensor in history.

The size of image: 60 km x 60 km approx., ground resolution 90 m x 90 m approximately.

The ASTER instrument was built in Japan for the Ministry of International Trade and Industry. A joint United States/Japan Science Team is responsible for instrument design, calibration, and data validation. ASTER is flying on the Terra satellite, which is managed by NASA's Goddard Space Flight Center, Greenbelt, MD.

Multimodel Kalman filtering for adaptive nonuniformity correction in infrared sensors.

PubMed

Pezoa, Jorge E; Hayat, Majeed M; Torres, Sergio N; Rahman, Md Saifur

2006-06-01

We present an adaptive technique for the estimation of nonuniformity parameters of infrared focal-plane arrays that is robust with respect to changes and uncertainties in scene and sensor characteristics. The proposed algorithm is based on using a bank of Kalman filters in parallel. Each filter independently estimates state variables comprising the gain and the bias matrices of the sensor, according to its own dynamic-model parameters. The supervising component of the algorithm then generates the final estimates of the state variables by forming a weighted superposition of all the estimates rendered by each Kalman filter. The weights are computed and updated iteratively, according to the a posteriori-likelihood principle. The performance of the estimator and its ability to compensate for fixed-pattern noise is tested using both simulated and real data obtained from two cameras operating in the mid- and long-wave infrared regime.

Pharmaceutical properties of two ethenzamide-gentisic acid cocrystal polymorphs: Drug release profiles, spectroscopic studies and theoretical calculations.

PubMed

Sokal, Agnieszka; Pindelska, Edyta; Szeleszczuk, Lukasz; Kolodziejski, Waclaw

2017-04-30

The aim of this study was to evaluate the stability and solubility of the polymorphic forms of the ethenzamide (ET) - gentisic acid (GA) cocrystals during standard technological processes leading to tablet formation, such as compression and excipient addition. In this work two polymorphic forms of pharmaceutical cocrystals (ETGA) were characterized by 13 C and 15 N solid-state nuclear magnetic resonance and Fourier transformed infrared spectroscopy. Spectroscopic studies were supported by gauge including projector augmented wave (GIPAW) calculations of chemical shielding constants.Polymorphs of cocrystals were easily identified and characterized on the basis of solid-state spectroscopic studies. ETGA cocrystals behaviour during direct compressionand tabletting with excipient addition were tested. In order to choose the best tablet composition with suitable properties for the pharmaceutical industry dissolution profile studies of tablets containing polymorphic forms of cocrystals with selected excipients were carried out. Copyright © 2017. Published by Elsevier B.V.

Background characterization techniques for target detection using scene metrics and pattern recognition

NASA Astrophysics Data System (ADS)

Noah, Paul V.; Noah, Meg A.; Schroeder, John W.; Chernick, Julian A.

1990-09-01

The U.S. Army has a requirement to develop systems for the detection and identification of ground targets in a clutter environment. Autonomous Homing Munitions (AHM) using infrared, visible, millimeter wave and other sensors are being investigated for this application. Advanced signal processing and computational approaches using pattern recognition and artificial intelligence techniques combined with multisensor data fusion have the potential to meet the Army's requirements for next generation ARM.

Simulated Tank Anti-Armor Gunnery System (STAGS-TOW).

DTIC Science & Technology

1983-05-01

to train TOW gunners. It is derived from a model previously developed for DRAGON. The system employs a terrain board with model enemy armored vehicles ...gunnery training. TOW is a crew-portable, heavy anti-tank weapon designed to attack and defeat armored vehicles and field fortifications. The missile is...a target area, converts the infrared energy to electrical signals and then to visible light and displays the visible light as a real-time scene for

Synthetic Infrared Scene: Improving the KARMA IRSG Module and Signature Modelling Tool SMAT

DTIC Science & Technology

2011-03-01

d’engagements impliquant des autodirecteurs infrarouges dans l’environnement de simulation KARMA. Le travail a été réalisé à partir de novembre 2008...infrarouges dans l’environnement de simulation KARMA. Le travail a été réalisé à partir de novembre 2008 jusqu’à mars 2011. Ce rapport de contrat est axé...74 13 Evaluating Performance Validator tool

Mapping the spectral variability in photosynthetic and non-photosynthetic vegetation, soils, and shade using AVIRIS

NASA Technical Reports Server (NTRS)

Roberts, Dar A.; Smith, Milton O.; Sabol, Donald E.; Adams, John B.; Ustin, Susan L.

1992-01-01

The primary objective of this research was to map as many spectrally distinct types of green vegetation (GV), non-photosynthetic vegetation (NPV), shade, and soil (endmembers) in an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) scene as is warranted by the spectral variability of the data. Once determined, a secondary objective was to interpret these endmembers and their abundances spatially and spectrally in an ecological context.

Wide-field depth-sectioning fluorescence microscopy using projector-generated patterned illumination

NASA Astrophysics Data System (ADS)

Delica, Serafin; Mar Blanca, Carlo

2007-10-01

We present a simple and cost-effective wide-field, depth-sectioning, fluorescence microscope utilizing a commercial multimedia projector to generate excitation patterns on the sample. Highly resolved optical sections of fluorescent pollen grains at 1.9 μm axial resolution are constructed using the structured illumination technique. This requires grid excitation patterns to be scanned across the sample, which is straightforwardly implemented by creating slideshows of gratings at different phases, projecting them onto the sample, and synchronizing camera acquisition with slide transition. In addition to rapid dynamic pattern generation, the projector provides high illumination power and spectral excitation selectivity. We exploit these properties by imaging mouse neural cells in cultures multistained with Alexa 488 and Cy3. The spectral and structural neural information is effectively resolved in three dimensions. The flexibility and commercial availability of this light source is envisioned to open multidimensional imaging to a broader user base.

Optical characterization of the InFocus TVT-6000 liquid crystal television (LCTV) using custom drive electronics

NASA Astrophysics Data System (ADS)

Duffey, Jason N.; Jones, Brian K.; Loudin, Jeffrey A.; Booth, Joseph J.

1995-03-01

Liquid crystal televisions are popular low-cost spatial light modulators. One LCTV of interest is found in the InFocus TVT-6000 television projector. A wavefront splitting interferometer has been constructed and analyzed for measuring the complex characteristics of these modulators, including phase and amplitude coupling. The results of this evaluation using the TVT-6000 projector drive electronics have been presented in a previous work. This work will present results of the complex characterizations of these modulators using custom drive electronics.

Invisible Cirrus Clouds

NASA Technical Reports Server (NTRS)

2002-01-01

The Moderate-resolution Imaging Spectroradiometer's (MODIS') cloud detection capability is so sensitive that it can detect clouds that would be indistinguishable to the human eye. This pair of images highlights MODIS' ability to detect what scientists call 'sub-visible cirrus.' The image on top shows the scene using data collected in the visible part of the electromagnetic spectrum-the part our eyes can see. Clouds are apparent in the center and lower right of the image, while the rest of the image appears to be relatively clear. However, data collected at 1.38um (lower image) show that a thick layer of previously undetected cirrus clouds obscures the entire scene. These kinds of cirrus are called 'sub-visible' because they can't be detected using only visible light. MODIS' 1.38um channel detects electromagnetic radiation in the infrared region of the spectrum. These images were made from data collected on April 4, 2000. Image courtesy Mark Gray, MODIS Atmosphere Team

Quality status display for a vibration welding process

DOEpatents

Spicer, John Patrick; Abell, Jeffrey A.; Wincek, Michael Anthony; Chakraborty, Debejyo; Bracey, Jennifer; Wang, Hui; Tavora, Peter W.; Davis, Jeffrey S.; Hutchinson, Daniel C.; Reardon, Ronald L.; Utz, Shawn

2017-03-28

A system includes a host machine and a status projector. The host machine is in electrical communication with a collection of sensors and with a welding controller that generates control signals for controlling the welding horn. The host machine is configured to execute a method to thereby process the sensory and control signals, as well as predict a quality status of a weld that is formed using the welding horn, including identifying any suspect welds. The host machine then activates the status projector to illuminate the suspect welds. This may occur directly on the welds using a laser projector, or on a surface of the work piece in proximity to the welds. The system and method may be used in the ultrasonic welding of battery tabs of a multi-cell battery pack in a particular embodiment. The welding horn and welding controller may also be part of the system.

Home theater projectors: the next big thing?

NASA Astrophysics Data System (ADS)

Chinnock, Christopher B.

2002-04-01

The business presentation market has traditionally been the mainstay of the projection business, but as these users find the projectors work well at showing movies at home, interest in the home entertainment market is heating up. The idea of creating a theater environment in the home, complete with big screen projector and quality audio system, is not new. Wealthy patrons have been doing it for years. But can the concept be extended to ordinary living rooms? Many think so. Already pioneers like Sony, InFocus, Toshiba and Plus Vision are offering first generation products - and others will follow. But this market will require projectors that have different performance characteristics than those designed for data projection. In this paper, we will discuss how the requirements for a home theater projector differ from those of a data projector. We will provide updated information on who is doing what in this segment and give some insight into the growth potential.

An Evaluation of Pixel-Based Methods for the Detection of Floating Objects on the Sea Surface

NASA Astrophysics Data System (ADS)

Borghgraef, Alexander; Barnich, Olivier; Lapierre, Fabian; Van Droogenbroeck, Marc; Philips, Wilfried; Acheroy, Marc

2010-12-01

Ship-based automatic detection of small floating objects on an agitated sea surface remains a hard problem. Our main concern is the detection of floating mines, which proved a real threat to shipping in confined waterways during the first Gulf War, but applications include salvaging, search-and-rescue operation, perimeter, or harbour defense. Detection in infrared (IR) is challenging because a rough sea is seen as a dynamic background of moving objects with size order, shape, and temperature similar to those of the floating mine. In this paper we have applied a selection of background subtraction algorithms to the problem, and we show that the recent algorithms such as ViBe and behaviour subtraction, which take into account spatial and temporal correlations within the dynamic scene, significantly outperform the more conventional parametric techniques, with only little prior assumptions about the physical properties of the scene.

Modeling and analysis of LWIR signature variability associated with 3D and BRDF effects

NASA Astrophysics Data System (ADS)

Adler-Golden, Steven; Less, David; Jin, Xuemin; Rynes, Peter

2016-05-01

Algorithms for retrieval of surface reflectance, emissivity or temperature from a spectral image almost always assume uniform illumination across the scene and horizontal surfaces with Lambertian reflectance. When these algorithms are used to process real 3-D scenes, the retrieved "apparent" values contain the strong, spatially dependent variations in illumination as well as surface bidirectional reflectance distribution function (BRDF) effects. This is especially problematic with horizontal or near-horizontal viewing, where many observed surfaces are vertical, and where horizontal surfaces can show strong specularity. The goals of this study are to characterize long-wavelength infrared (LWIR) signature variability in a HSI 3-D scene and develop practical methods for estimating the true surface values. We take advantage of synthetic near-horizontal imagery generated with the high-fidelity MultiService Electro-optic Signature (MuSES) model, and compare retrievals of temperature and directional-hemispherical reflectance using standard sky downwelling illumination and MuSES-based non-uniform environmental illumination.

Real-time depth processing for embedded platforms

NASA Astrophysics Data System (ADS)

Rahnama, Oscar; Makarov, Aleksej; Torr, Philip

2017-05-01

Obtaining depth information of a scene is an important requirement in many computer-vision and robotics applications. For embedded platforms, passive stereo systems have many advantages over their active counterparts (i.e. LiDAR, Infrared). They are power efficient, cheap, robust to lighting conditions and inherently synchronized to the RGB images of the scene. However, stereo depth estimation is a computationally expensive task that operates over large amounts of data. For embedded applications which are often constrained by power consumption, obtaining accurate results in real-time is a challenge. We demonstrate a computationally and memory efficient implementation of a stereo block-matching algorithm in FPGA. The computational core achieves a throughput of 577 fps at standard VGA resolution whilst consuming less than 3 Watts of power. The data is processed using an in-stream approach that minimizes memory-access bottlenecks and best matches the raster scan readout of modern digital image sensors.

A Martin-Puplett cartridge FIR interferometer

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

Smith, Roger J.; Penniman, Edwin E.; Jarboe, Thomas R.

2004-10-01

A compact prealigned Martin-Puplett interferometer (MPI) cartridge for plasma interferometry is described. The MPI cartridge groups all components of a MP interferometer, with the exception of the end mirror for the scene beam, on a stand-alone rigid platform. The interferometer system is completed by positioning a cartridge anywhere along and coaxial with the scene beam, considerably reducing the amount of effort in alignment over a discrete component layout. This allows the interferometer to be expanded to any number of interferometry chords consistent with optical access, limited only by the laser power. The cartridge interferometer has been successfully incorporated as amore » second chord on the Helicity Injected Torus II (HIT-II) far infrared interferometer system and a comparison with the discrete component system is presented. Given the utility and compactness of the cartridge, a possible design for a five-chord interferometer arrangement on the HIT-II device is described.« less

Image reconstruction of dynamic infrared single-pixel imaging system

NASA Astrophysics Data System (ADS)

Tong, Qi; Jiang, Yilin; Wang, Haiyan; Guo, Limin

2018-03-01

Single-pixel imaging technique has recently received much attention. Most of the current single-pixel imaging is aimed at relatively static targets or the imaging system is fixed, which is limited by the number of measurements received through the single detector. In this paper, we proposed a novel dynamic compressive imaging method to solve the imaging problem, where exists imaging system motion behavior, for the infrared (IR) rosette scanning system. The relationship between adjacent target images and scene is analyzed under different system movement scenarios. These relationships are used to build dynamic compressive imaging models. Simulation results demonstrate that the proposed method can improve the reconstruction quality of IR image and enhance the contrast between the target and the background in the presence of system movement.

Depth measurements through controlled aberrations of projected patterns.

PubMed

Birch, Gabriel C; Tyo, J Scott; Schwiegerling, Jim

2012-03-12

Three-dimensional displays have become increasingly present in consumer markets. However, the ability to capture three-dimensional images in space confined environments and without major modifications to current cameras is uncommon. Our goal is to create a simple modification to a conventional camera that allows for three dimensional reconstruction. We require such an imaging system have imaging and illumination paths coincident. Furthermore, we require that any three-dimensional modification to a camera also permits full resolution 2D image capture.Here we present a method of extracting depth information with a single camera and aberrated projected pattern. A commercial digital camera is used in conjunction with a projector system with astigmatic focus to capture images of a scene. By using an astigmatic projected pattern we can create two different focus depths for horizontal and vertical features of a projected pattern, thereby encoding depth. By designing an aberrated projected pattern, we are able to exploit this differential focus in post-processing designed to exploit the projected pattern and optical system. We are able to correlate the distance of an object at a particular transverse position from the camera to ratios of particular wavelet coefficients.We present our information regarding construction, calibration, and images produced by this system. The nature of linking a projected pattern design and image processing algorithms will be discussed.

Geometric and radiometric preprocessing of airborne visible/infrared imaging spectrometer (AVIRIS) data in rugged terrain for quantitative data analysis

NASA Technical Reports Server (NTRS)

Meyer, Peter; Green, Robert O.; Staenz, Karl; Itten, Klaus I.

1994-01-01

A geocoding procedure for remotely sensed data of airborne systems in rugged terrain is affected by several factors: buffeting of the aircraft by turbulence, variations in ground speed, changes in altitude, attitude variations, and surface topography. The current investigation was carried out with an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) scene of central Switzerland (Rigi) from NASA's Multi Aircraft Campaign (MAC) in Europe (1991). The parametric approach reconstructs for every pixel the observation geometry based on the flight line, aircraft attitude, and surface topography. To utilize the data for analysis of materials on the surface, the AVIRIS data are corrected to apparent reflectance using algorithms based on MODTRAN (moderate resolution transfer code).

Preliminary Geologic/spectral Analysis of LANDSAT-4 Thematic Mapper Data, Wind River/bighorn Basin Area, Wyoming

NASA Technical Reports Server (NTRS)

Lang, H. R.; Conel, J. E.; Paylor, E. D.

1984-01-01

A LIDQA evaluation for geologic applications of a LANDSAT TM scene covering the Wind River/Bighorn Basin area, Wyoming, is examined. This involves a quantitative assessment of data quality including spatial and spectral characteristics. Analysis is concentrated on the 6 visible, near infrared, and short wavelength infrared bands. Preliminary analysis demonstrates that: (1) principal component images derived from the correlation matrix provide the most useful geologic information. To extract surface spectral reflectance, the TM radiance data must be calibrated. Scatterplots demonstrate that TM data can be calibrated and sensor response is essentially linear. Low instrumental offset and gain settings result in spectral data that do not utilize the full dynamic range of the TM system.

Infrared fix pattern noise reduction method based on Shearlet Transform

NASA Astrophysics Data System (ADS)

Rong, Shenghui; Zhou, Huixin; Zhao, Dong; Cheng, Kuanhong; Qian, Kun; Qin, Hanlin

2018-06-01

The non-uniformity correction (NUC) is an effective way to reduce fix pattern noise (FPN) and improve infrared image quality. The temporal high-pass NUC method is a kind of practical NUC method because of its simple implementation. However, traditional temporal high-pass NUC methods rely deeply on the scene motion and suffer image ghosting and blurring. Thus, this paper proposes an improved NUC method based on Shearlet Transform (ST). First, the raw infrared image is decomposed into multiscale and multi-orientation subbands by ST and the FPN component mainly exists in some certain high-frequency subbands. Then, high-frequency subbands are processed by the temporal filter to extract the FPN due to its low-frequency characteristics. Besides, each subband has a confidence parameter to determine the degree of FPN, which is estimated by the variance of subbands adaptively. At last, the process of NUC is achieved by subtracting the estimated FPN component from the original subbands and the corrected infrared image can be obtained by the inverse ST. The performance of the proposed method is evaluated with real and synthetic infrared image sequences thoroughly. Experimental results indicate that the proposed method can reduce heavily FPN with less roughness and RMSE.

Improved detection probability of low level light and infrared image fusion system

NASA Astrophysics Data System (ADS)

Luo, Yuxiang; Fu, Rongguo; Zhang, Junju; Wang, Wencong; Chang, Benkang

2018-02-01

Low level light(LLL) image contains rich information on environment details, but is easily affected by the weather. In the case of smoke, rain, cloud or fog, much target information will lose. Infrared image, which is from the radiation produced by the object itself, can be "active" to obtain the target information in the scene. However, the image contrast and resolution is bad, the ability of the acquisition of target details is very poor, and the imaging mode does not conform to the human visual habit. The fusion of LLL and infrared image can make up for the deficiency of each sensor and give play to the advantages of single sensor. At first, we show the hardware design of fusion circuit. Then, through the recognition probability calculation of the target(one person) and the background image(trees), we find that the trees detection probability of LLL image is higher than that of the infrared image, and the person detection probability of the infrared image is obviously higher than that of LLL image. The detection probability of fusion image for one person and trees is higher than that of single detector. Therefore, image fusion can significantly enlarge recognition probability and improve detection efficiency.

Current LWIR HSI Remote Sensing Activities at Defence R&D Canada - Valcartier

DTIC Science & Technology

2009-10-01

measures the IR radiation from a target scene which is optically combined onto a single detector out-of-phase with the IR radiation from a corresponding...Hyper-Cam-LW. The MODDIFS project involves the development of a leading edge infrared ( IR ) hyperspectral sensor optimized for the standoff detection...essentially offer the optical subtraction capability of the CATSI system but at high-spatial resolution using an MCT focal plane array of 8484

Full-color laser cathode ray tube (L-CRT) projector

NASA Astrophysics Data System (ADS)

Kozlovskiy, Vladimir; Nasibov, Alexander S.; Popov, Yuri M.; Reznikov, Parvel V.; Skasyrsky, Yan K.

1995-04-01

A full color TV projector based on three laser cathode-ray tubes (L-CRT) is described. A water-cooled laser screen (LS) is the radiation element of the L-CRT. We have produced three main colors (blue, green and red) by using the LS made of three II-VI compounds: ZnSe ((lambda) equals 475 nm), CdS ((lambda) equals 530 nm) and ZnCdSe (630 nm). The total light flow reaches 1500 Lm, and the number of elements per line is not less than 1000. The LS efficiency may be about 10 Lm/W. In our experiments we have tested new electron optics: - (30 - 37) kV are applied to the cathode unit of the electron gun; the anode of the e-gun and the e-beam intensity modulator are under low potential; the LS has a potential + (30 - 37) kV. The accelerating voltage is divided into two parts, and this enables us to diminish the size and weight of the projector.

Structured Light Based 3d Scanning for Specular Surface by the Combination of Gray Code and Phase Shifting

NASA Astrophysics Data System (ADS)

Zhang, Yujia; Yilmaz, Alper

2016-06-01

Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i) A complete setup of the structured light based 3D scanning system; (ii) A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the advantages of our new combined coding method.

Field-Sequential Electronic Stereoscopic Projector

NASA Astrophysics Data System (ADS)

Lipton, Lenny

1989-07-01

Culminating a research and development project spanning many years, StereoGraphics Corporation has succeeded in bringing to market the first field-sequential electronic stereoscopic projector. The product is based on a modification of Electrohome and Barco projectors. Our design goal was to produce a projector capable of displaying an image on a six-foot (or larger) diagonal screen for an audience of 50 or 60 people, or for an individual using a simulator. A second goal was to produce an image that required only passive polarizing glasses rather than powered, tethered visors. Two major design challenges posed themselves. First, it was necessary to create an electro-optical modulator which could switch the characteristic of polarized light at field rate, and second, it was necessary to produce a bright green CRT with short persistence to prevent crosstalk between left and right fields. To solve the first problem, development was undertaken to produce the required electro-optical modulator. The second problem was solved with the help of a vendor specializing in high performance CRT's.

Six-color solid state illuminator for cinema projector

NASA Astrophysics Data System (ADS)

Huang, Junejei; Wang, Yuchang

2014-09-01

Light source for cinema projector requires reliability, high brightness, good color and 3D for without silver screens. To meet these requirements, a laser-phosphor based solid state illuminator with 6 primary colors is proposed. The six primary colors are divided into two groups and include colors of R1, R2, G1, G2, B1 and B2. Colors of B1, B2 and R2 come from lasers of wavelengths 440 nm, 465 nm and 639 nm. Color of G1 comes from G-phosphor pumped by B2 laser. Colors of G2 and R1 come from Y-phosphor pumped by B1 laser. Two groups of colors are combined by a multiband filter and working by alternately switching B1 and B2 lasers. The combined two sequences of three colors are sent to the 3-chip cinema projector and synchronized with frame rate of 120Hz. In 2D mode, the resulting 6 primary colors provide a very wide color gamut. In 3D mode, two groups of red, green and blue primary colors provide two groups of images that received by left and right eyes.

Generic precise augmented reality guiding system and its calibration method based on 3D virtual model.

PubMed

Liu, Miao; Yang, Shourui; Wang, Zhangying; Huang, Shujun; Liu, Yue; Niu, Zhenqi; Zhang, Xiaoxuan; Zhu, Jigui; Zhang, Zonghua

2016-05-30

Augmented reality system can be applied to provide precise guidance for various kinds of manual works. The adaptability and guiding accuracy of such systems are decided by the computational model and the corresponding calibration method. In this paper, a novel type of augmented reality guiding system and the corresponding designing scheme are proposed. Guided by external positioning equipment, the proposed system can achieve high relative indication accuracy in a large working space. Meanwhile, the proposed system is realized with a digital projector and the general back projection model is derived with geometry relationship between digitized 3D model and the projector in free space. The corresponding calibration method is also designed for the proposed system to obtain the parameters of projector. To validate the proposed back projection model, the coordinate data collected by a 3D positioning equipment is used to calculate and optimize the extrinsic parameters. The final projecting indication accuracy of the system is verified with subpixel pattern projecting technique.

Bispectral infrared forest fire detection and analysis using classification techniques

NASA Astrophysics Data System (ADS)

Aranda, Jose M.; Melendez, Juan; de Castro, Antonio J.; Lopez, Fernando

2004-01-01

Infrared cameras are well established as a useful tool for fire detection, but their use for quantitative forest fire measurements faces difficulties, due to the complex spatial and spectral structure of fires. In this work it is shown that some of these difficulties can be overcome by applying classification techniques, a standard tool for the analysis of satellite multispectral images, to bi-spectral images of fires. Images were acquired by two cameras that operate in the medium infrared (MIR) and thermal infrared (TIR) bands. They provide simultaneous and co-registered images, calibrated in brightness temperatures. The MIR-TIR scatterplot of these images can be used to classify the scene into different fire regions (background, ashes, and several ember and flame regions). It is shown that classification makes possible to obtain quantitative measurements of physical fire parameters like rate of spread, embers temperature, and radiated power in the MIR and TIR bands. An estimation of total radiated power and heat release per unit area is also made and compared with values derived from heat of combustion and fuel consumption.

Bloodstain detection and discrimination impacted by spectral shift when using an interference filter-based visible and near-infrared multispectral crime scene imaging system

NASA Astrophysics Data System (ADS)

Yang, Jie; Messinger, David W.; Dube, Roger R.

2018-03-01

Bloodstain detection and discrimination from nonblood substances on various substrates are critical in forensic science as bloodstains are a critical source for confirmatory DNA tests. Conventional bloodstain detection methods often involve time-consuming sample preparation, a chance of harm to investigators, the possibility of destruction of blood samples, and acquisition of too little data at crime scenes either in the field or in the laboratory. An imaging method has the advantages of being nondestructive, noncontact, real-time, and covering a large field-of-view. The abundant spectral information provided by multispectral imaging makes it a potential presumptive bloodstain detection and discrimination method. This article proposes an interference filter (IF) based area scanning three-spectral-band crime scene imaging system used for forensic bloodstain detection and discrimination. The impact of large angle of views on the spectral shift of calibrated IFs is determined, for both detecting and discriminating bloodstains from visually similar substances on multiple substrates. Spectral features in the visible and near-infrared portion employed by the relative band depth method are used. This study shows that 1 ml bloodstain on black felt, gray felt, red felt, white cotton, white polyester, and raw wood can be detected. Bloodstains on the above substrates can be discriminated from cola, coffee, ketchup, orange juice, red wine, and green tea.

In Vivo Near Infrared Virtual Intraoperative Surgical Photoacoustic Optical Coherence Tomography

PubMed Central

Lee, Donghyun; Lee, Changho; Kim, Sehui; Zhou, Qifa; Kim, Jeehyun; Kim, Chulhong

2016-01-01

Since its first implementation in otolaryngological surgery nearly a century ago, the surgical microscope has improved the accuracy and the safety of microsurgeries. However, the microscope shows only a magnified surface view of the surgical region. To overcome this limitation, either optical coherence tomography (OCT) or photoacoustic microscopy (PAM) has been independently combined with conventional surgical microscope. Herein, we present a near-infrared virtual intraoperative photoacoustic optical coherence tomography (NIR-VISPAOCT) system that combines both PAM and OCT with a conventional surgical microscope. Using optical scattering and absorption, the NIR-VISPAOCT system simultaneously provides surgeons with real-time comprehensive biological information such as tumor margins, tissue structure, and a magnified view of the region of interest. Moreover, by utilizing a miniaturized beam projector, it can back-project 2D cross-sectional PAM and OCT images onto the microscopic view plane. In this way, both microscopic and cross-sectional PAM and OCT images are concurrently displayed on the ocular lens of the microscope. To verify the usability of the NIR-VISPAOCT system, we demonstrate simulated surgeries, including in vivo image-guided melanoma resection surgery and in vivo needle injection of carbon particles into a mouse thigh. The proposed NIR-VISPAOCT system has potential applications in neurosurgery, ophthalmological surgery, and other microsurgeries. PMID:27731390

Non-destructive 3D shape measurement of transparent and black objects with thermal fringes

NASA Astrophysics Data System (ADS)

Brahm, Anika; Rößler, Conrad; Dietrich, Patrick; Heist, Stefan; Kühmstedt, Peter; Notni, Gunther

2016-05-01

Fringe projection is a well-established optical method for the non-destructive contactless three-dimensional (3D) measurement of object surfaces. Typically, fringe sequences in the visible wavelength range (VIS) are projected onto the surfaces of objects to be measured and are observed by two cameras in a stereo vision setup. The reconstruction is done by finding corresponding pixels in both cameras followed by triangulation. Problems can occur if the properties of some materials disturb the measurements. If the objects are transparent, translucent, reflective, or strongly absorbing in the VIS range, the projected patterns cannot be recorded properly. To overcome these challenges, we present a new alternative approach in the infrared (IR) region of the electromagnetic spectrum. For this purpose, two long-wavelength infrared (LWIR) cameras (7.5 - 13 μm) are used to detect the emitted heat radiation from surfaces which is induced by a pattern projection unit driven by a CO2 laser (10.6 μm). Thus, materials like glass or black objects, e.g. carbon fiber materials, can be measured non-destructively without the need of any additional paintings. We will demonstrate the basic principles of this heat pattern approach and show two types of 3D systems based on a freeform mirror and a GOBO wheel (GOes Before Optics) projector unit.

NCAP projection displays

NASA Astrophysics Data System (ADS)

Havens, John R.; Ishioka, J.; Jones, Philip J.; Lau, Aldrich; Tomita, Akira; Asano, A.; Konuma, Nobuhiro; Sato, Kazuhiko; Takemoto, Iwao

1997-05-01

Projectors based on polymer-eNCAPsulated liquid crystals can provide bright displays suitable for use in conference rooms with normal lighting. Contrast is generated by light scattering among the droplets, rather than by light absorption with crossed polarizers. We have demonstrated a full-color, compact projector showing 1200 ANSI lumens with 200 watts of lamp power - a light efficiency of 6 lumens/watt. This projector is based on low-voltage NCAP material, highly reflective CMOS die, and matched illumination and projection optics. We will review each of these areas and discuss the integrated system performance.

Evaluation of the InFocus TVT-6000 LCTV

NASA Astrophysics Data System (ADS)

Duffey, Jason N.; Jones, Brian K.; Gregory, Don A.; McClain, John L., Jr.

1994-03-01

Liquid crystal televisions have become increasingly popular as low-cost spatial light modulators. While the early devices suffered from poor resolution and low contrast, recent models compare favorably to the more traditional (and expensive) modulators. One of the most recent LCTVs is found in the InFocus TVT-6000 television projector. The panels in this projector have 480 X 440 pixels with a 1.32' diagonal clear aperture. A wavefront splitting interferometer has been constructed and analyzed for measuring the complex characteristics of these modulators, including phase and amplitude coupling. The results of this evaluation will be presented.

Fast, accurate, small-scale 3D scene capture using a low-cost depth sensor

PubMed Central

Carey, Nicole; Nagpal, Radhika; Werfel, Justin

2017-01-01

Commercially available depth sensing devices are primarily designed for domains that are either macroscopic, or static. We develop a solution for fast microscale 3D reconstruction, using off-the-shelf components. By the addition of lenses, precise calibration of camera internals and positioning, and development of bespoke software, we turn an infrared depth sensor designed for human-scale motion and object detection into a device with mm-level accuracy capable of recording at up to 30Hz. PMID:28758159

Stripe nonuniformity correction for infrared imaging system based on single image optimization

NASA Astrophysics Data System (ADS)

Hua, Weiping; Zhao, Jufeng; Cui, Guangmang; Gong, Xiaoli; Ge, Peng; Zhang, Jiang; Xu, Zhihai

2018-06-01

Infrared imaging is often disturbed by stripe nonuniformity noise. Scene-based correction method can effectively reduce the impact of stripe noise. In this paper, a stripe nonuniformity correction method based on differential constraint is proposed. Firstly, the gray distribution of stripe nonuniformity is analyzed and the penalty function is constructed by the difference of horizontal gradient and vertical gradient. With the weight function, the penalty function is optimized to obtain the corrected image. Comparing with other single-frame approaches, experiments show that the proposed method performs better in both subjective and objective analysis, and does less damage to edge and detail. Meanwhile, the proposed method runs faster. We have also discussed the differences between the proposed idea and multi-frame methods. Our method is finally well applied in hardware system.

Infrared spectroscopy and spectroscopic imaging in forensic science.

PubMed

Ewing, Andrew V; Kazarian, Sergei G

2017-01-16

Infrared spectroscopy and spectroscopic imaging, are robust, label free and inherently non-destructive methods with a high chemical specificity and sensitivity that are frequently employed in forensic science research and practices. This review aims to discuss the applications and recent developments of these methodologies in this field. Furthermore, the use of recently emerged Fourier transform infrared (FT-IR) spectroscopic imaging in transmission, external reflection and Attenuated Total Reflection (ATR) modes are summarised with relevance and potential for forensic science applications. This spectroscopic imaging approach provides the opportunity to obtain the chemical composition of fingermarks and information about possible contaminants deposited at a crime scene. Research that demonstrates the great potential of these techniques for analysis of fingerprint residues, explosive materials and counterfeit drugs will be reviewed. The implications of this research for the examination of different materials are considered, along with an outlook of possible future research avenues for the application of vibrational spectroscopic methods to the analysis of forensic samples.

The use of thematic mapper data for land cover discrimination: Preliminary results from the UK SATMaP programme

NASA Technical Reports Server (NTRS)

Jackson, M. J.; Baker, J. R.; Townshend, J. R. G.; Gayler, J. E.; Hardy, J. R.

1983-01-01

The principal objectives of the UK SATMaP program are to determine thematic mapper (TM) performance with particular reference to spatial resolution properties and geometric characteristics of the data. So far, analysis is restricted to images from the U.S. and concentrates on spectra and radiometric properties. The results indicate that the data are inherently three dimensional compared with the two dimensional character of MSS data. Preliminary classification results indicate the importance of the near infrared band (TM 4), at least one middle infrared band (TM 5 or TM 6) and at least one of the visible bands (preferably either TM 3 or TM 1). The thermal infrared also appears to have discriminatory ability despite its coarser spatial resolution. For band 4 the forward and reverse scans show somewhat different spectral responses in one scene but this effect is absent in the other analyzed. From examination of the histograms it would appear that the full 8-bit quantization is not being effectively utilized for all the bands.

Aerial 3D display by use of a 3D-shaped screen with aerial imaging by retro-reflection (AIRR)

NASA Astrophysics Data System (ADS)

Kurokawa, Nao; Ito, Shusei; Yamamoto, Hirotsugu

2017-06-01

The purpose of this paper is to realize an aerial 3D display. We design optical system that employs a projector below a retro-reflector and a 3D-shaped screen. A floating 3D image is formed with aerial imaging by retro-reflection (AIRR). Our proposed system is composed of a 3D-shaped screen, a projector, a quarter-wave retarder, a retro-reflector, and a reflective polarizer. Because AIRR forms aerial images that are plane-symmetric of the light sources regarding the reflective polarizer, the shape of the 3D screen is inverted from a desired aerial 3D image. In order to expand viewing angle, the 3D-shaped screen is surrounded by a retro-reflector. In order to separate the aerial image from reflected lights on the retro- reflector surface, the retro-reflector is tilted by 30 degrees. A projector is located below the retro-reflector at the same height of the 3D-shaped screen. The optical axis of the projector is orthogonal to the 3D-shaped screen. Scattered light on the 3D-shaped screen forms the aerial 3D image. In order to demonstrate the proposed optical design, a corner-cube-shaped screen is used for the 3D-shaped screen. Thus, the aerial 3D image is a cube that is floating above the reflective polarizer. For example, an aerial green cube is formed by projecting a calculated image on the 3D-shaped screen. The green cube image is digitally inverted in depth by our developed software. Thus, we have succeeded in forming aerial 3D image with our designed optical system.

Infrared Thermography Approach for Effective Shielding Area of Field Smoke Based on Background Subtraction and Transmittance Interpolation.

PubMed

Tang, Runze; Zhang, Tonglai; Chen, Yongpeng; Liang, Hao; Li, Bingyang; Zhou, Zunning

2018-05-06

Effective shielding area is a crucial indicator for the evaluation of the infrared smoke-obscuring effectiveness on the battlefield. The conventional methods for assessing the shielding area of the smoke screen are time-consuming and labor intensive, in addition to lacking precision. Therefore, an efficient and convincing technique for testing the effective shielding area of the smoke screen has great potential benefits in the smoke screen applications in the field trial. In this study, a thermal infrared sensor with a mid-wavelength infrared (MWIR) range of 3 to 5 μm was first used to capture the target scene images through clear as well as obscuring smoke, at regular intervals. The background subtraction in motion detection was then applied to obtain the contour of the smoke cloud at each frame. The smoke transmittance at each pixel within the smoke contour was interpolated based on the data that was collected from the image. Finally, the smoke effective shielding area was calculated, based on the accumulation of the effective shielding pixel points. One advantage of this approach is that it utilizes only one thermal infrared sensor without any other additional equipment in the field trial, which significantly contributes to the efficiency and its convenience. Experiments have been carried out to demonstrate that this approach can determine the effective shielding area of the field infrared smoke both practically and efficiently.

Hyperspectral Infrared Imaging of Flames Using a Spectrally Scanning Fabry-Perot Filter

NASA Technical Reports Server (NTRS)

Rawlins, W. T.; Lawrence, W. G.; Marinelli, W. J.; Allen, M. G.; Piltch, N. (Technical Monitor)

2001-01-01

The temperatures and compositions of gases in and around flames can be diagnosed using infrared emission spectroscopy to observe molecular band shapes and intensities. We have combined this approach with a low-order scanning Fabry-Perot filter and an infrared camera to obtain spectrally scanned infrared emission images of a laboratory flame and exhaust plume from 3.7 to 5.0 micrometers, at a spectral resolution of 0.043 micrometers, and a spatial resolution of 1 mm. The scanning filter or AIRIS (Adaptive Infrared Imaging Spectroradiometer) is a Fabry-Perot etalon operating in low order (mirror spacing = wavelength) such that the central spot, containing a monochromatic image of the scene, is viewed by the detector array. The detection system is a 128 x 128 liquid-nitrogen-cooled InSb focal plane array. The field of view is controlled by a 50 mm focal length multielement lens and an V4.8 aperture, resulting in an image 6.4 x 6.4 cm in extent at the flame and a depth of field of approximately 4 cm. Hyperspectral images above a laboratory CH4/air flame show primarily the strong emission from CO2 at 4.3 micrometers, and weaker emissions from CO and H2O. We discuss techniques to analyze the spectra, and plans to use this instrument in microgravity flame spread experiments.

Infrared thermography: A non-invasive window into thermal physiology.

PubMed

Tattersall, Glenn J

2016-12-01

Infrared thermography is a non-invasive technique that measures mid to long-wave infrared radiation emanating from all objects and converts this to temperature. As an imaging technique, the value of modern infrared thermography is its ability to produce a digitized image or high speed video rendering a thermal map of the scene in false colour. Since temperature is an important environmental parameter influencing animal physiology and metabolic heat production an energetically expensive process, measuring temperature and energy exchange in animals is critical to understanding physiology, especially under field conditions. As a non-contact approach, infrared thermography provides a non-invasive complement to physiological data gathering. One caveat, however, is that only surface temperatures are measured, which guides much research to those thermal events occurring at the skin and insulating regions of the body. As an imaging technique, infrared thermal imaging is also subject to certain uncertainties that require physical modelling, which is typically done via built-in software approaches. Infrared thermal imaging has enabled different insights into the comparative physiology of phenomena ranging from thermogenesis, peripheral blood flow adjustments, evaporative cooling, and to respiratory physiology. In this review, I provide background and guidelines for the use of thermal imaging, primarily aimed at field physiologists and biologists interested in thermal biology. I also discuss some of the better known approaches and discoveries revealed from using thermal imaging with the objective of encouraging more quantitative assessment. Copyright © 2016 Elsevier Inc. All rights reserved.

Analysis and Compensation for Lateral Chromatic Aberration in a Color Coding Structured Light 3D Measurement System.

PubMed

Huang, Junhui; Xue, Qi; Wang, Zhao; Gao, Jianmin

2016-09-03

While color-coding methods have improved the measuring efficiency of a structured light three-dimensional (3D) measurement system, they decreased the measuring accuracy significantly due to lateral chromatic aberration (LCA). In this study, the LCA in a structured light measurement system is analyzed, and a method is proposed to compensate the error caused by the LCA. Firstly, based on the projective transformation, a 3D error map of LCA is constructed in the projector images by using a flat board and comparing the image coordinates of red, green and blue circles with the coordinates of white circles at preselected sample points within the measurement volume. The 3D map consists of the errors, which are the equivalent errors caused by LCA of the camera and projector. Then in measurements, error values of LCA are calculated and compensated to correct the projector image coordinates through the 3D error map and a tri-linear interpolation method. Eventually, 3D coordinates with higher accuracy are re-calculated according to the compensated image coordinates. The effectiveness of the proposed method is verified in the following experiments.

Color image processing and object tracking workstation

NASA Technical Reports Server (NTRS)

Klimek, Robert B.; Paulick, Michael J.

1992-01-01

A system is described for automatic and semiautomatic tracking of objects on film or video tape which was developed to meet the needs of the microgravity combustion and fluid science experiments at NASA Lewis. The system consists of individual hardware parts working under computer control to achieve a high degree of automation. The most important hardware parts include 16 mm film projector, a lens system, a video camera, an S-VHS tapedeck, a frame grabber, and some storage and output devices. Both the projector and tapedeck have a computer interface enabling remote control. Tracking software was developed to control the overall operation. In the automatic mode, the main tracking program controls the projector or the tapedeck frame incrementation, grabs a frame, processes it, locates the edge of the objects being tracked, and stores the coordinates in a file. This process is performed repeatedly until the last frame is reached. Three representative applications are described. These applications represent typical uses and include tracking the propagation of a flame front, tracking the movement of a liquid-gas interface with extremely poor visibility, and characterizing a diffusion flame according to color and shape.

Image system for three dimensional, 360 DEGREE, time sequence surface mapping of moving objects

DOEpatents

Lu, Shin-Yee

1998-01-01

A three-dimensional motion camera system comprises a light projector placed between two synchronous video cameras all focused on an object-of-interest. The light projector shines a sharp pattern of vertical lines (Ronchi ruling) on the object-of-interest that appear to be bent differently to each camera by virtue of the surface shape of the object-of-interest and the relative geometry of the cameras, light projector and object-of-interest Each video frame is captured in a computer memory and analyzed. Since the relative geometry is known and the system pre-calibrated, the unknown three-dimensional shape of the object-of-interest can be solved for by matching the intersections of the projected light lines with orthogonal epipolar lines corresponding to horizontal rows in the video camera frames. A surface reconstruction is made and displayed on a monitor screen. For 360.degree. all around coverage of theobject-of-interest, two additional sets of light projectors and corresponding cameras are distributed about 120.degree. apart from one another.

A micro-machined source transducer for a parametric array in air.

PubMed

Lee, Haksue; Kang, Daesil; Moon, Wonkyu

2009-04-01

Parametric array applications in air, such as highly directional parametric loudspeaker systems, usually rely on large radiators to generate the high-intensity primary beams required for nonlinear interactions. However, a conventional transducer, as a primary wave projector, requires a great deal of electrical power because its electroacoustic efficiency is very low due to the large characteristic mechanical impedance in air. The feasibility of a micro-machined ultrasonic transducer as an efficient finite-amplitude wave projector was studied. A piezoelectric micro-machined ultrasonic transducer array consisting of lead zirconate titanate uni-morph elements was designed and fabricated for this purpose. Theoretical and experimental evaluations showed that a micro-machined ultrasonic transducer array can be used as an efficient source transducer for a parametric array in air. The beam patterns and propagation curves of the difference frequency wave and the primary wave generated by the micro-machined ultrasonic transducer array were measured. Although the theoretical results were based on ideal parametric array models, the theoretical data explained the experimental results reasonably well. These experiments demonstrated the potential of micro-machined primary wave projector.

Analysis and Compensation for Lateral Chromatic Aberration in a Color Coding Structured Light 3D Measurement System

PubMed Central

Huang, Junhui; Xue, Qi; Wang, Zhao; Gao, Jianmin

2016-01-01

While color-coding methods have improved the measuring efficiency of a structured light three-dimensional (3D) measurement system, they decreased the measuring accuracy significantly due to lateral chromatic aberration (LCA). In this study, the LCA in a structured light measurement system is analyzed, and a method is proposed to compensate the error caused by the LCA. Firstly, based on the projective transformation, a 3D error map of LCA is constructed in the projector images by using a flat board and comparing the image coordinates of red, green and blue circles with the coordinates of white circles at preselected sample points within the measurement volume. The 3D map consists of the errors, which are the equivalent errors caused by LCA of the camera and projector. Then in measurements, error values of LCA are calculated and compensated to correct the projector image coordinates through the 3D error map and a tri-linear interpolation method. Eventually, 3D coordinates with higher accuracy are re-calculated according to the compensated image coordinates. The effectiveness of the proposed method is verified in the following experiments. PMID:27598174

Acoustic beam control in biomimetic projector via velocity gradient

NASA Astrophysics Data System (ADS)

Gao, Xiaowei; Zhang, Yu; Cao, Wenwu; Dong, Erqian; Song, Zhongchang; Li, Songhai; Tang, Liguo; Zhang, Sai

2016-07-01

A biomimetic projector (BioP) based on computerized tomography of pygmy sperm whale's biosonar system has been designed using gradient-index (GRIN) material. The directivity of this BioP device was investigated as function of frequency and the velocity gradient of the GRIN material. A strong beam control over a broad bandwidth at the subwavelength scale has been achieved. Compared with a bare subwavelength source, the main lobe pressure of the BioP is about five times as high and the angular resolution is one order of magnitude better. Our results indicate that this BioP has excellent application potential in miniaturized underwater sonars.

Acoustic beam control in biomimetic projector via velocity gradient

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

Gao, Xiaowei; Dong, Erqian; Song, Zhongchang

A biomimetic projector (BioP) based on computerized tomography of pygmy sperm whale's biosonar system has been designed using gradient-index (GRIN) material. The directivity of this BioP device was investigated as function of frequency and the velocity gradient of the GRIN material. A strong beam control over a broad bandwidth at the subwavelength scale has been achieved. Compared with a bare subwavelength source, the main lobe pressure of the BioP is about five times as high and the angular resolution is one order of magnitude better. Our results indicate that this BioP has excellent application potential in miniaturized underwater sonars.

MEASURING PROJECTOR

DOEpatents

Franck, J.V.; Broadhead, P.S.; Skiff, E.W.

1959-07-14

A semiautomatic measuring projector particularly adapted for measurement of the coordinates of photographic images of particle tracks as prcduced in a bubble or cloud chamber is presented. A viewing screen aids the operator in selecting a particle track for measurement. After approximate manual alignment, an image scanning system coupled to a servo control provides automatic exact alignment of a track image with a reference point. The apparatus can follow along a track with a continuous motion while recording coordinate data at various selected points along the track. The coordinate data is recorded on punched cards for subsequent computer calculation of particle trajectory, momentum, etc.

A novel scene-based non-uniformity correction method for SWIR push-broom hyperspectral sensors

NASA Astrophysics Data System (ADS)

Hu, Bin-Lin; Hao, Shi-Jing; Sun, De-Xin; Liu, Yin-Nian

2017-09-01

A novel scene-based non-uniformity correction (NUC) method for short-wavelength infrared (SWIR) push-broom hyperspectral sensors is proposed and evaluated. This method relies on the assumption that for each band there will be ground objects with similar reflectance to form uniform regions when a sufficient number of scanning lines are acquired. The uniform regions are extracted automatically through a sorting algorithm, and are used to compute the corresponding NUC coefficients. SWIR hyperspectral data from airborne experiment are used to verify and evaluate the proposed method, and results show that stripes in the scenes have been well corrected without any significant information loss, and the non-uniformity is less than 0.5%. In addition, the proposed method is compared to two other regular methods, and they are evaluated based on their adaptability to the various scenes, non-uniformity, roughness and spectral fidelity. It turns out that the proposed method shows strong adaptability, high accuracy and efficiency.

A novel false color mapping model-based fusion method of visual and infrared images

NASA Astrophysics Data System (ADS)

Qi, Bin; Kun, Gao; Tian, Yue-xin; Zhu, Zhen-yu

2013-12-01

A fast and efficient image fusion method is presented to generate near-natural colors from panchromatic visual and thermal imaging sensors. Firstly, a set of daytime color reference images are analyzed and the false color mapping principle is proposed according to human's visual and emotional habits. That is, object colors should remain invariant after color mapping operations, differences between infrared and visual images should be enhanced and the background color should be consistent with the main scene content. Then a novel nonlinear color mapping model is given by introducing the geometric average value of the input visual and infrared image gray and the weighted average algorithm. To determine the control parameters in the mapping model, the boundary conditions are listed according to the mapping principle above. Fusion experiments show that the new fusion method can achieve the near-natural appearance of the fused image, and has the features of enhancing color contrasts and highlighting the infrared brilliant objects when comparing with the traditional TNO algorithm. Moreover, it owns the low complexity and is easy to realize real-time processing. So it is quite suitable for the nighttime imaging apparatus.

MIMA, a miniaturized Fourier infrared spectrometer for Mars ground exploration: Part I. Concept and expected performance

NASA Astrophysics Data System (ADS)

Bellucci, G.; Saggin, B.; Fonti, S.; Biondi, D.; Cerulli, P.; De Luca, M.; Altieri, F.; Mattana, A.; Alberti, E.; Marzo, G.; Zasova, L.

2007-10-01

The Mars Infrared MApper (MIMA) is a FT-IR miniaturised spectrometer which is being developed for ESA ExoMars Pasteur mission. The Martian Infrared MApper Fourier Spectrometer is designed to provide remote measurements of mineralogy and atmosphere of the scene surrounding a Martian rover and guide it to key targets for detailed in situ measurements by other rover experiments. Among the main scientific objectives of the MIMA instrument are to assist the rover in rock/soils selection for further in-situ investigation and to identify rocks and soils on the Martian surface which provide evidence of past/present biological activity. The instrument is also designed to measure the water vapour abundance and vertical distribution and its diurnal and seasonal variation, dust opacity, optical properties, composition, diurnal and seasonal variation. The instrument is a double pendulum interferometer providing spectra in the 2 - 25 μm wavelength domain with a resolving power of 1000 at 2 μm and 80 at 25 μm. The radiometric performances are SNR > 40 in the near infrared and a NEDe = 0.002 in the thermal region. The instrument design is very compact, with a total mass of 1kg and an average power consumption of 5 W.

Cloud Top Scanning radiometer (CTS): User's guide

NASA Technical Reports Server (NTRS)

Brown, K. S.

1981-01-01

The CTS maps the Earth's surface with a resolution of 0.1 km from an altitude of 18km with 60km side-to-side coverage of the field. It has three spectral channels. The 0.625 micrometer centered visual channel detects reflectance to within 1 percent. The 6.75 micrometer centered water vapor channel detects changes in temperature of less than one degree Kelvin at 175 K. The 11.5 micrometer centered infrared window channel detects changes of less one half degree Kelvin at 175 K. The data can be converted graphically into three display images of the scene. Values for scene temperature and albedo are calculated from calibration equations. The equations were derived from in-situ and laboratory measurements. Intercomparisons of the flight data temperatures with ground based and other remote sensor results established the certainty of the derived temperature values to within 3 K over a wide temperature range (180 to 320 K). The system performance, calibration, and operation is successful and the engineering information describing this system should prove useful to scientists and potential users of the data.

Satellite and airborne oil spill remote sensing: State of the art and application to the BP DeepWater Horizon oil spill

USGS Publications Warehouse

Leifer, I.; Clark, R.; Jones, C.; Holt, B.; Svejkovsky, J.; Swayze, G.

2011-01-01

The vast, persistent, and unconstrained oil release from the DeepWater Horizon (DWH) challenged the spill response, which required accurate quantitative oil assessment at synoptic and operational scales. Experienced observers are the mainstay of oil spill response. Key limitations are weather, scene illumination geometry, and few trained observers, leading to potential observer bias. Aiding the response was extensive passive and active satellite and airborne remote sensing, including intelligent system augmentation, reviewed herein. Oil slick appearance strongly depends on many factors like emulsion composition and scene geometry, yielding false positives and great thickness uncertainty. Oil thicknesses and the oil to water ratios for thick slicks were derived quantitatively with a new spectral library approach based on the shape and depth of spectral features related to C-H vibration bands. The approach used near infrared, imaging spectroscopy data from the AVIRIS (Airborne Visual/InfraRed Imaging Spectrometer) instrument on the NASA ER-2 stratospheric airplane. Extrapolation to the total slick used MODIS satellite visual-spectrum broadband data, which observes sunglint reflection from surface slicks; i.e., indicates the presence of oil and/or surfactant slicks. Oil slick emissivity is less than seawater's allowing MODIS thermal infrared (TIR) nighttime identification; however, water temperature variations can cause false positives. Some strong emissivity features near 6.7 and 9.7 ??m could be analyzed as for the AVIRIS short wave infrared features, but require high spectral resolution data. TIR spectral trends can allow fresh/weathered oil discrimination. Satellite Synthetic Aperture Radar (SSAR) provided synoptic data under all-sky conditions by observing oil dampening of capillary waves; however, SSAR typically cannot discriminate thick from thin oil slicks. Airborne UAVSAR's significantly greater signal-to-noise ratio and fine spatial resolution allowed successful mapping of oil slick thickness-related patterns. Laser induced fluorescence (LIF) can quantify oil thicknesses by Raman scattering line distortions, but saturates for >20-??m thick oil and depends on oil optical characteristics and sea state. Combined with laser bathymetry LIF can provide submerged oil remote sensing.

LWIR pupil imaging and prospects for background compensation

NASA Astrophysics Data System (ADS)

LeVan, Paul; Sakoglu, Ünal; Stegall, Mark; Pierce, Greg

2015-08-01

A previous paper described LWIR Pupil Imaging with a sensitive, low-flux focal plane array, and behavior of this type of system for higher flux operations as understood at the time. We continue this investigation, and report on a more detailed characterization of the system over a broad range of pixel fluxes. This characterization is then shown to enable non-uniformity correction over the flux range, using a standard approach. Since many commercial tracking platforms include a "guider port" that accepts pulse width modulation (PWM) error signals, we have also investigated a variation on the use of this port to "dither" the tracking platform in synchronization with the continuous collection of infrared images. The resulting capability has a broad range of applications that extend from generating scene motion in the laboratory for quantifying performance of "realtime, scene-based non-uniformity correction" approaches, to effectuating subtraction of bright backgrounds by alternating viewing aspect between a point source and adjacent, source-free backgrounds.

Study of LANDSAT-D thematic mapper performance as applied to hydrocarbon exploration

NASA Technical Reports Server (NTRS)

Everett, J. R. (Principal Investigator)

1983-01-01

Two fully processed test tapes were enhanced and evaluated at scales up to 1:10,000, using both hardcopy output and interactive screen display. A large scale, the Detroit, Michigan scene shows evidence of an along line data slip every sixteenth line in TM channel 2. Very large scale products generated in false color using channels 1,3, and 4 should be very acceptable for interpretation at scales up to 1:50,000 and useful for change mapping probably up to scale 1:24,000. Striping visible in water bodies for both natural and color products indicates that the detector calibration is probably performing below preflight specification. For a set of 512 x 512 windows within the NE Arkansas scene, the variance-covariance matrices were computed and principal component analyses performed. Initial analysis suggests that the shortwave infrared TM 5 and 6 channels are a highly significant data source. The thermal channel (TM 7) shows negative correlation with TM 1 and 4.

Identification of recently handled materials by analysis of latent human fingerprints using infrared spectromicroscopy.

PubMed

Grant, Ashleigh; Wilkinson, T J; Holman, Derek R; Martin, Michael C

2005-09-01

Analysis of fingerprints has predominantly focused on matching the pattern of ridges to a specific person as a form of identification. The present work focuses on identifying extrinsic materials that are left within a person's fingerprint after recent handling of such materials. Specifically, we employed infrared spectromicroscopy to locate and positively identify microscopic particles from a mixture of common materials in the latent human fingerprints of volunteer subjects. We were able to find and correctly identify all test substances based on their unique infrared spectral signatures. Spectral imaging is demonstrated as a method for automating recognition of specific substances in a fingerprint. We also demonstrate the use of attenuated total reflectance (ATR) and synchrotron-based infrared spectromicroscopy for obtaining high-quality spectra from particles that were too thick or too small, respectively, for reflection/absorption measurements. We believe the application of this rapid, nondestructive analytical technique to the forensic study of latent human fingerprints has the potential to add a new layer of information available to investigators. Using fingerprints to not only identify who was present at a crime scene, but also to link who was handling key materials, will be a powerful investigative tool.

Infrared Thermal Imaging System on a Mobile Phone

PubMed Central

Lee, Fu-Feng; Chen, Feng; Liu, Jing

2015-01-01

A novel concept towards pervasively available low-cost infrared thermal imaging system lunched on a mobile phone (MTIS) was proposed and demonstrated in this article. Through digestion on the evolutional development of milestone technologies in the area, it can be found that the portable and low-cost design would become the main stream of thermal imager for civilian purposes. As a representative trial towards this important goal, a MTIS consisting of a thermal infrared module (TIM) and mobile phone with embedded exclusive software (IRAPP) was presented. The basic strategy for the TIM construction is illustrated, including sensor adoption and optical specification. The user-oriented software was developed in the Android environment by considering its popularity and expandability. Computational algorithms with non-uniformity correction and scene-change detection are established to optimize the imaging quality and efficiency of TIM. The performance experiments and analysis indicated that the currently available detective distance for the MTIS is about 29 m. Furthermore, some family-targeted utilization enabled by MTIS was also outlined, such as sudden infant death syndrome (SIDS) prevention, etc. This work suggests a ubiquitous way of significantly extending thermal infrared image into rather wide areas especially health care in the coming time. PMID:25942639

Hyperspectral target detection analysis of a cluttered scene from a virtual airborne sensor platform using MuSES

NASA Astrophysics Data System (ADS)

Packard, Corey D.; Viola, Timothy S.; Klein, Mark D.

2017-10-01

The ability to predict spectral electro-optical (EO) signatures for various targets against realistic, cluttered backgrounds is paramount for rigorous signature evaluation. Knowledge of background and target signatures, including plumes, is essential for a variety of scientific and defense-related applications including contrast analysis, camouflage development, automatic target recognition (ATR) algorithm development and scene material classification. The capability to simulate any desired mission scenario with forecast or historical weather is a tremendous asset for defense agencies, serving as a complement to (or substitute for) target and background signature measurement campaigns. In this paper, a systematic process for the physical temperature and visible-through-infrared radiance prediction of several diverse targets in a cluttered natural environment scene is presented. The ability of a virtual airborne sensor platform to detect and differentiate targets from a cluttered background, from a variety of sensor perspectives and across numerous wavelengths in differing atmospheric conditions, is considered. The process described utilizes the thermal and radiance simulation software MuSES and provides a repeatable, accurate approach for analyzing wavelength-dependent background and target (including plume) signatures in multiple band-integrated wavebands (multispectral) or hyperspectrally. The engineering workflow required to combine 3D geometric descriptions, thermal material properties, natural weather boundary conditions, all modes of heat transfer and spectral surface properties is summarized. This procedure includes geometric scene creation, material and optical property attribution, and transient physical temperature prediction. Radiance renderings, based on ray-tracing and the Sandford-Robertson BRDF model, are coupled with MODTRAN for the inclusion of atmospheric effects. This virtual hyperspectral/multispectral radiance prediction methodology has been extensively validated and provides a flexible process for signature evaluation and algorithm development.

Use of a compact range approach to evaluate rf and dual-mode missiles

NASA Astrophysics Data System (ADS)

Willis, Kenneth E.; Weiss, Yosef

2000-07-01

This paper describes a hardware-in-the-loop (HWIL) system developed for testing Radio Frequency (RF), Infra-Red (IR), and Dual-Mode missile seekers. The system consists of a unique hydraulic five-axis (three seeker axes plus two target axes) Flight Motion Table (FMT), an off-axis parabolic reflector, and electronics required to generate the signals to the RF feeds. RF energy that simulates the target is fed into the reflector from three orthogonal feeds mounted on the inner target axis, at the focal point area of the parabolic reflector. The parabolic reflector, together with the three RF feeds (the Compact Range), effectively produces a far-field image of the target. Both FMT target axis motion and electronic control of the RF beams (deflection) modify the simulated line-of-sight target angles. Multiple targets, glint, multi-path, ECM, and clutter can be introduced electronically. To evaluate dual-mode seekers, the center section of the parabolic reflector is replaced with an IR- transparent, but RF-reflective section. An IR scene projector mounts to the FMT target axes, with its image focused on the intersection of the FMT seeker axes. The system eliminates the need for a large anechoic chamber and 'Target Wall' or target motion system used with conventional HWIL systems. This reduces acquisition and operating costs of the facility.

3D thermography in non-destructive testing of composite structures

NASA Astrophysics Data System (ADS)

Hellstein, Piotr; Szwedo, Mariusz

2016-12-01

The combination of 3D scanners and infrared cameras has lead to the introduction of 3D thermography. Such analysis produces results in the form of three-dimensional thermograms, where the temperatures are mapped on a 3D model reconstruction of the inspected object. All work in the field of 3D thermography focused on its utility in passive thermography inspections. The authors propose a new real-time 3D temperature mapping method, which for the first time can be applied to active thermography analyses. All steps required to utilise 3D thermography are discussed, starting from acquisition of three-dimensional and infrared data, going through image processing and scene reconstruction, finishing with thermal projection and ray-tracing visualisation techniques. The application of the developed method was tested during diagnosis of several industrial composite structures—boats, planes and wind turbine blades.

Computed tomography imaging spectrometer (CTIS) with 2D reflective grating for ultraviolet to long-wave infrared detection especially useful for surveying transient events

NASA Technical Reports Server (NTRS)

Muller, Richard E. (Inventor); Mouroulis, Pantazis Z. (Inventor); Maker, Paul D. (Inventor); Wilson, Daniel W. (Inventor)

2003-01-01

The optical system of this invention is an unique type of imaging spectrometer, i.e. an instrument that can determine the spectra of all points in a two-dimensional scene. The general type of imaging spectrometer under which this invention falls has been termed a computed-tomography imaging spectrometer (CTIS). CTIS's have the ability to perform spectral imaging of scenes containing rapidly moving objects or evolving features, hereafter referred to as transient scenes. This invention, a reflective CTIS with an unique two-dimensional reflective grating, can operate in any wavelength band from the ultraviolet through long-wave infrared. Although this spectrometer is especially useful for rapidly occurring events it is also useful for investigation of some slow moving phenomena as in the life sciences.

Near-infrared high-resolution real-time omnidirectional imaging platform for drone detection

NASA Astrophysics Data System (ADS)

Popovic, Vladan; Ott, Beat; Wellig, Peter; Leblebici, Yusuf

2016-10-01

Recent technological advancements in hardware systems have made higher quality cameras. State of the art panoramic systems use them to produce videos with a resolution of 9000 x 2400 pixels at a rate of 30 frames per second (fps).1 Many modern applications use object tracking to determine the speed and the path taken by each object moving through a scene. The detection requires detailed pixel analysis between two frames. In fields like surveillance systems or crowd analysis, this must be achieved in real time.2 In this paper, we focus on the system-level design of multi-camera sensor acquiring near-infrared (NIR) spectrum and its ability to detect mini-UAVs in a representative rural Swiss environment. The presented results show the UAV detection from the trial that we conducted during a field trial in August 2015.

The AEDC aerospace chamber 7V: An advanced test capability for infrared surveillance and seeker sensors

NASA Technical Reports Server (NTRS)

Simpson, W. R.

1994-01-01

An advanced sensor test capability is now operational at the Air Force Arnold Engineering Development Center (AEDC) for calibration and performance characterization of infrared sensors. This facility, known as the 7V, is part of a broad range of test capabilities under development at AEDC to provide complete ground test support to the sensor community for large-aperture surveillance sensors and kinetic kill interceptors. The 7V is a state-of-the-art cryo/vacuum facility providing calibration and mission simulation against space backgrounds. Key features of the facility include high-fidelity scene simulation with precision track accuracy and in-situ target monitoring, diffraction limited optical system, NIST traceable broadband and spectral radiometric calibration, outstanding jitter control, environmental systems for 20 K, high-vacuum, low-background simulation, and an advanced data acquisition system.

Image system for three dimensional, 360{degree}, time sequence surface mapping of moving objects

DOEpatents

Lu, S.Y.

1998-12-22

A three-dimensional motion camera system comprises a light projector placed between two synchronous video cameras all focused on an object-of-interest. The light projector shines a sharp pattern of vertical lines (Ronchi ruling) on the object-of-interest that appear to be bent differently to each camera by virtue of the surface shape of the object-of-interest and the relative geometry of the cameras, light projector and object-of-interest. Each video frame is captured in a computer memory and analyzed. Since the relative geometry is known and the system pre-calibrated, the unknown three-dimensional shape of the object-of-interest can be solved for by matching the intersections of the projected light lines with orthogonal epipolar lines corresponding to horizontal rows in the video camera frames. A surface reconstruction is made and displayed on a monitor screen. For 360{degree} all around coverage of the object-of-interest, two additional sets of light projectors and corresponding cameras are distributed about 120{degree} apart from one another. 20 figs.

Dynamic modeling method for infrared smoke based on enhanced discrete phase model

NASA Astrophysics Data System (ADS)

Zhang, Zhendong; Yang, Chunling; Zhang, Yan; Zhu, Hongbo

2018-03-01

The dynamic modeling of infrared (IR) smoke plays an important role in IR scene simulation systems and its accuracy directly influences the system veracity. However, current IR smoke models cannot provide high veracity, because certain physical characteristics are frequently ignored in fluid simulation; simplifying the discrete phase as a continuous phase and ignoring the IR decoy missile-body spinning. To address this defect, this paper proposes a dynamic modeling method for IR smoke, based on an enhanced discrete phase model (DPM). A mathematical simulation model based on an enhanced DPM is built and a dynamic computing fluid mesh is generated. The dynamic model of IR smoke is then established using an extended equivalent-blackbody-molecule model. Experiments demonstrate that this model realizes a dynamic method for modeling IR smoke with higher veracity.

The Role of the Modern Planetarium as an Effective Tool in Astronomy Education and Public Outreach

NASA Astrophysics Data System (ADS)

Albin, Edward F.

2016-01-01

As the planetarium approaches its 100th anniversary, today's planetarium educator must reflect on the role of such technology in contemporary astronomy education and outreach. The projection planetarium saw "first light" in 1923 at the Carl Zeiss factory in Jena, Germany. During the 20th century, the concept of a star projector beneath a dome flourished as an extraordinary device for the teaching of astronomy. The evolution of digital technology over the past twenty years has dramatically changed the perception / utilization of the planetarium. The vast majority of modern star theaters have shifted entirely to fulldome digital projection systems, abandoning the once ubiquitous electromechanical star projector altogether. These systems have evolved into ultra-high resolution theaters, capable of projecting imagery, videos, and any web-based media onto the dome. Such capability has rendered the planetarium as a multi-disciplinary tool, broadening its educational appeal to a wide variety of fields -- including life sciences, the humanities, and even entertainment venues. However, we suggest that what is at the heart of the planetarium appeal is having a theater adept at projecting a beautiful / accurate star-field. To this end, our facility chose to keep / maintain its aging Zeiss V star projector while adding fulldome digital capability. Such a hybrid approach provides an excellent compromise between presenting state of the art multimedia while at the same time maintaining the ability to render a stunning night sky. In addition, our facility maintains two portable StarLab planetariums for outreach purposes, one unit with a classic electromechanical star projector and the other having a relatively inexpensive fulldome projection system. With a combination of these technologies, it is possible for the planetarium to be an effective tool for astronomical education / outreach well into the 21st century.

Real-time imaging of methane gas leaks using a single-pixel camera.

PubMed

Gibson, Graham M; Sun, Baoqing; Edgar, Matthew P; Phillips, David B; Hempler, Nils; Maker, Gareth T; Malcolm, Graeme P A; Padgett, Miles J

2017-02-20

We demonstrate a camera which can image methane gas at video rates, using only a single-pixel detector and structured illumination. The light source is an infrared laser diode operating at 1.651μm tuned to an absorption line of methane gas. The light is structured using an addressable micromirror array to pattern the laser output with a sequence of Hadamard masks. The resulting backscattered light is recorded using a single-pixel InGaAs detector which provides a measure of the correlation between the projected patterns and the gas distribution in the scene. Knowledge of this correlation and the patterns allows an image to be reconstructed of the gas in the scene. For the application of locating gas leaks the frame rate of the camera is of primary importance, which in this case is inversely proportional to the square of the linear resolution. Here we demonstrate gas imaging at ~25 fps while using 256 mask patterns (corresponding to an image resolution of 16×16). To aid the task of locating the source of the gas emission, we overlay an upsampled and smoothed image of the low-resolution gas image onto a high-resolution color image of the scene, recorded using a standard CMOS camera. We demonstrate for an illumination of only 5mW across the field-of-view imaging of a methane gas leak of ~0.2 litres/minute from a distance of ~1 metre.

A biomimetic projector with high subwavelength directivity based on dolphin biosonar

NASA Astrophysics Data System (ADS)

Zhang, Yu; Gao, Xiaowei; Zhang, Sai; Cao, Wenwu; Tang, Liguo; Wang, Ding; Li, Yan

2014-09-01

Based on computed tomography of a Yangtze finless porpoise's biosonar system, a biomimetic structure was designed to include air cavity, gradient-index material, and steel outer-structure mimicking air sacs, melon, and skull, respectively. The mainlobe pressure was about three times higher, the angular resolution was one order of magnitude higher, and the effective source size was orders of magnitude larger than those of the subwavelength source without the biomimetic structure. The superior subwavelength directivity over a broad bandwidth suggests potential applications of this biomimetic projector in underwater sonar, medical ultrasonography, and other related applications.

Projector primary-based optimization for superimposed projection mappings

NASA Astrophysics Data System (ADS)

Ahmed, Bilal; Lee, Jong Hun; Lee, Yong Yi; Lee, Kwan H.

2018-01-01

Recently, many researchers have focused on fully overlapping projections for three-dimensional (3-D) projection mapping systems but reproducing a high-quality appearance using this technology still remains a challenge. On top of existing color compensation-based methods, much effort is still required to faithfully reproduce an appearance that is free from artifacts, colorimetric inconsistencies, and inappropriate illuminance over the 3-D projection surface. According to our observation, this is due to the fact that overlapping projections are treated as an additive-linear mixture of color. However, this is not the case according to our elaborated observations. We propose a method that enables us to use high-quality appearance data that are measured from original objects and regenerate the same appearance by projecting optimized images using multiple projectors, ensuring that the projection-rendered results look visually close to the real object. We prepare our target appearances by photographing original objects. Then, using calibrated projector-camera pairs, we compensate for missing geometric correspondences to make our method robust against noise. The heart of our method is a target appearance-driven adaptive sampling of the projection surface followed by a representation of overlapping projections in terms of the projector-primary response. This gives off projector-primary weights to facilitate blending and the system is applied with constraints. These samples are used to populate a light transport-based system. Then, the system is solved minimizing the error to get the projection images in a noise-free manner by utilizing intersample overlaps. We ensure that we make the best utilization of available hardware resources to recreate projection mapped appearances that look as close to the original object as possible. Our experimental results show compelling results in terms of visual similarity and colorimetric error.

Autographic theme extraction

USGS Publications Warehouse

Edson, D.; Colvocoresses, Alden P.

1973-01-01

Remote-sensor images, including aerial and space photographs, are generally recorded on film, where the differences in density create the image of the scene. With panchromatic and multiband systems the density differences are recorded in shades of gray. On color or color infrared film, with the emulsion containing dyes sensitive to different wavelengths, a color image is created by a combination of color densities. The colors, however, can be separated by filtering or other techniques, and the color image reduced to monochromatic images in which each of the separated bands is recorded as a function of the gray scale.

A quantitative analysis of TIMS data obtained on the Learjet 23 at various altitudes

NASA Technical Reports Server (NTRS)

Jaggi, S.

1992-01-01

A series of Thermal Infrared Multispectral Scanner (TIMS) data acquisition flights were conducted on the NASA Learjet 23 at different altitudes over a test site. The objective was to monitor the performance of the TIMS (its estimation of the brightness temperatures of the ground scene) with increasing altitude. The results do not show any significant correlation between the brightness temperatures and the altitude. The analysis indicates that the estimation of the temperatures is a function of the accuracy of the atmospheric correction used for each altitude.

Atmospheric Compensation and Surface Temperature and Emissivity Retrieval with LWIR Hyperspectral Imagery

NASA Astrophysics Data System (ADS)

Pieper, Michael

Accurate estimation or retrieval of surface emissivity spectra from long-wave infrared (LWIR) or Thermal Infrared (TIR) hyperspectral imaging data acquired by airborne or space-borne sensors is necessary for many scientific and defense applications. The at-aperture radiance measured by the sensor is a function of the ground emissivity and temperature, modified by the atmosphere. Thus the emissivity retrieval process consists of two interwoven steps: atmospheric compensation (AC) to retrieve the ground radiance from the measured at-aperture radiance and temperature-emissivity separation (TES) to separate the temperature and emissivity from the ground radiance. In-scene AC (ISAC) algorithms use blackbody-like materials in the scene, which have a linear relationship between their ground radiances and at-aperture radiances determined by the atmospheric transmission and upwelling radiance. Using a clear reference channel to estimate the ground radiance, a linear fitting of the at-aperture radiance and estimated ground radiance is done to estimate the atmospheric parameters. TES algorithms for hyperspectral imaging data assume that the emissivity spectra for solids are smooth compared to the sharp features added by the atmosphere. The ground temperature and emissivity are found by finding the temperature that provides the smoothest emissivity estimate. In this thesis we develop models to investigate the sensitivity of AC and TES to the basic assumptions enabling their performance. ISAC assumes that there are perfect blackbody pixels in a scene and that there is a clear channel, which is never the case. The developed ISAC model explains how the quality of blackbody-like pixels affect the shape of atmospheric estimates and the clear channel assumption affects their magnitude. Emissivity spectra for solids usually have some roughness. The TES model identifies four sources of error: the smoothing error of the emissivity spectrum, the emissivity error from using the incorrect temperature, and the errors caused by sensor noise and wavelength calibration. The ways these errors interact determines the overall TES performance. Since the AC and TES processes are interwoven, any errors in AC are transferred to TES and the final temperature and emissivity estimates. Combining the two models, shape errors caused by the blackbody assumption are transferred to the emissivity estimates, where magnitude errors from the clear channel assumption are compensated by TES temperature induced emissivity errors. The ability for the temperature induced error to compensate for such atmospheric errors makes it difficult to determine the correct atmospheric parameters for a scene. With these models we are able to determine the expected quality of estimated emissivity spectra based on the quality of blackbody-like materials on the ground, the emissivity of the materials being searched for, and the properties of the sensor. The quality of material emissivity spectra is a key factor in determining detection performance for a material in a scene.

A hyperspectral image projector for hyperspectral imagers

NASA Astrophysics Data System (ADS)

Rice, Joseph P.; Brown, Steven W.; Neira, Jorge E.; Bousquet, Robert R.

2007-04-01

We have developed and demonstrated a Hyperspectral Image Projector (HIP) intended for system-level validation testing of hyperspectral imagers, including the instrument and any associated spectral unmixing algorithms. HIP, based on the same digital micromirror arrays used in commercial digital light processing (DLP*) displays, is capable of projecting any combination of many different arbitrarily programmable basis spectra into each image pixel at up to video frame rates. We use a scheme whereby one micromirror array is used to produce light having the spectra of endmembers (i.e. vegetation, water, minerals, etc.), and a second micromirror array, optically in series with the first, projects any combination of these arbitrarily-programmable spectra into the pixels of a 1024 x 768 element spatial image, thereby producing temporally-integrated images having spectrally mixed pixels. HIP goes beyond conventional DLP projectors in that each spatial pixel can have an arbitrary spectrum, not just arbitrary color. As such, the resulting spectral and spatial content of the projected image can simulate realistic scenes that a hyperspectral imager will measure during its use. Also, the spectral radiance of the projected scenes can be measured with a calibrated spectroradiometer, such that the spectral radiance projected into each pixel of the hyperspectral imager can be accurately known. Use of such projected scenes in a controlled laboratory setting would alleviate expensive field testing of instruments, allow better separation of environmental effects from instrument effects, and enable system-level performance testing and validation of hyperspectral imagers as used with analysis algorithms. For example, known mixtures of relevant endmember spectra could be projected into arbitrary spatial pixels in a hyperspectral imager, enabling tests of how well a full system, consisting of the instrument + calibration + analysis algorithm, performs in unmixing (i.e. de-convolving) the spectra in all pixels. We discuss here the performance of a visible prototype HIP. The technology is readily extendable to the ultraviolet and infrared spectral ranges, and the scenes can be static or dynamic.

CIRiS: Compact Infrared Radiometer in Space

NASA Astrophysics Data System (ADS)

Osterman, D. P.; Collins, S.; Ferguson, J.; Good, W.; Kampe, T.; Rohrschneider, R.; Warden, R.

2016-09-01

The Compact Infrared Radiometer in Space (CIRiS) is a thermal infrared radiometric imaging instrument under development by Ball Aerospace for a Low Earth Orbit mission on a CubeSat spacecraft. Funded by the NASA Earth Science Technology Office's In-Space Validation of Earth Science Technology (InVEST) program, the mission objective is technology demonstration for improved on-orbit radiometric calibration. The CIRiS calibration approach uses a scene select mirror to direct three calibration views to the focal plane array and to transfer the resulting calibrated response to earth images. The views to deep space and two blackbody sources, including one at a selectable temperature, provide multiple options for calibration optimization. Two new technologies, carbon nanotube blackbody sources and microbolometer focal plane arrays with reduced pixel sizes, enable improved radiometric performance within the constrained 6U CubeSat volume. The CIRiS instrument's modular design facilitates subsystem modifications as required by future mission requirements. CubeSat constellations of CIRiS and derivative instruments offer an affordable approach to achieving revisit times as short as one day for diverse applications including water resource and drought management, cloud, aerosol, and dust studies, and land use and vegetation monitoring. Launch is planned for 2018.

Real time imaging of infrared scene data generated by the Naval Postgraduate School Infrared Search and Target Designation (NPS-IRSTD) system

NASA Astrophysics Data System (ADS)

Baca, Michael J.

1990-09-01

A system to display images generated by the Naval Postgraduate School Infrared Search and Target Designation (a modified AN/SAR-8 Advanced Development Model) in near real time was developed using a 33 MHz NIC computer as the central controller. This computer was enhanced with a Data Translation DT2861 Frame Grabber for image processing and an interface board designed and constructed at NPS to provide synchronization between the IRSTD and Frame Grabber. Images are displayed in false color in a video raster format on a 512 by 480 pixel resolution monitor. Using FORTRAN, programs have been written to acquire, unscramble, expand and display a 3 deg sector of data. The time line for acquisition, processing and display has been analyzed and repetition periods of less than four seconds for successive screen displays have been achieved. This represents a marked improvement over previous methods necessitating slower Direct Memory Access transfers of data into the Frame Grabber. Recommendations are made for further improvements to enhance the speed and utility of images produced.

Determination of the microbolometric FPA's responsivity with imaging system's radiometric considerations

NASA Astrophysics Data System (ADS)

Gogler, Slawomir; Bieszczad, Grzegorz; Krupinski, Michal

2013-10-01

Thermal imagers and used therein infrared array sensors are subject to calibration procedure and evaluation of their voltage sensitivity on incident radiation during manufacturing process. The calibration procedure is especially important in so-called radiometric cameras, where accurate radiometric quantities, given in physical units, are of concern. Even though non-radiometric cameras are not expected to stand up to such elevated standards, it is still important, that the image faithfully represents temperature variations across the scene. Detectors used in thermal camera are illuminated by infrared radiation transmitted through an infrared transmitting optical system. Often an optical system, when exposed to uniform Lambertian source forms a non-uniform irradiation distribution in its image plane. In order to be able to carry out an accurate non-uniformity correction it is essential to correctly predict irradiation distribution from a uniform source. In the article a non-uniformity correction method has been presented, that takes into account optical system's radiometry. Predictions of the irradiation distribution have been confronted with measured irradiance values. Presented radiometric model allows fast and accurate non-uniformity correction to be carried out.

Saline Valley

NASA Image and Video Library

2001-10-22

These images of the Saline Valley area, California, were acquired March 30, 2000 and cover a full ASTER scene (60 by 60 km). Each image displays data from a different spectral region, and illustrates the complementary nature of surface compositional information available as a function of wavelength. This image displays visible and near infrared bands 3, 2, and 1 in red, green, and blue (RGB). Vegetation appears red, snow and dry salt lakes are white, and exposed rocks are brown, gray, yellow and blue. Rock colors mainly reflect the presence of iron minerals, and variations in albedo. Figure 1 displays short wavelength infrared bands 4, 6, and 8 as RGB. In this wavelength region, clay, carbonate, and sulfate minerals have diagnostic absorption features, resulting in distinct colors on the image. For example, limestones are yellow-green, and purple areas are kaolinite-rich. Figure 2 displays thermal infrared bands 13, 12 and 10 as RGB. In this wavelength region, variations in quartz content appear as more or less red; carbonate rocks are green, and mafic volcanic rocks are purple. The image is located at 36.8 degrees north latitude and 117.7 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA11164

An adaptive enhancement algorithm for infrared video based on modified k-means clustering

NASA Astrophysics Data System (ADS)

Zhang, Linze; Wang, Jingqi; Wu, Wen

2016-09-01

In this paper, we have proposed a video enhancement algorithm to improve the output video of the infrared camera. Sometimes the video obtained by infrared camera is very dark since there is no clear target. In this case, infrared video should be divided into frame images by frame extraction, in order to carry out the image enhancement. For the first frame image, which can be divided into k sub images by using K-means clustering according to the gray interval it occupies before k sub images' histogram equalization according to the amount of information per sub image, we used a method to solve a problem that final cluster centers close to each other in some cases; and for the other frame images, their initial cluster centers can be determined by the final clustering centers of the previous ones, and the histogram equalization of each sub image will be carried out after image segmentation based on K-means clustering. The histogram equalization can make the gray value of the image to the whole gray level, and the gray level of each sub image is determined by the ratio of pixels to a frame image. Experimental results show that this algorithm can improve the contrast of infrared video where night target is not obvious which lead to a dim scene, and reduce the negative effect given by the overexposed pixels adaptively in a certain range.

Development of Yellow Sand Image Products Using Infrared Brightness Temperature Difference Method

NASA Astrophysics Data System (ADS)

Ha, J.; Kim, J.; Kwak, M.; Ha, K.

2007-12-01

A technique for detection of airborne yellow sand dust using meteorological satellite has been developed from various bands from ultraviolet to infrared channels. Among them, Infrared (IR) channels have an advantage of detecting aerosols over high reflecting surface as well as during nighttime. There had been suggestion of using brightness temperature difference (BTD) between 11 and 12¥ìm. We have found that the technique is highly depends on surface temperature, emissivity, and zenith angle, which results in changing the threshold of BTD. In order to overcome these problems, we have constructed the background brightness temperature threshold of BTD and then aerosol index (AI) has been determined from subtracting the background threshold from BTD of our interested scene. Along with this, we utilized high temporal coverage of geostationary satellite, MTSAT, to improve the reliability of the determined AI signal. The products have been evaluated by comparing the forecasted wind field with the movement fiend of AI. The statistical score test illustrates that this newly developed algorithm produces a promising result for detecting mineral dust by reducing the errors with respect to the current BTD method.

The Observing Modes of JWST/NIRISS

NASA Astrophysics Data System (ADS)

Taylor, Joanna M.; NIRISS Team

2018-06-01

The Near Infrared Imager and Slitless Spectrograph (NIRISS) is a contribution of the Canadian Space Agency to the James Webb Space Telescope (JWST). NIRISS complements the other near-infrared science instruments onboard JWST by providing capabilities for (a) low resolution grism spectroscopy between 0.8 and 2.2 µm over the entire field of view, with the possibility of observing the same scene with orthogonal dispersion directions to disentangle blended objects; (b) medium-resolution grism spectroscopy between 0.6 and 2.8 µm that has been optimized to provide high spectrophotometric stability for time-series observations of transiting exoplanets; (c) aperture masking interferometry that provides high angular resolution of 70 - 400 mas at wavelengths between 2.8 and 4.8 µm and (d) parallel imaging through a set of filters that are closely matched to NIRCam's.In this poster, we discuss each of these modes and present simulations of how they might typically be used to address specific scientific questions.

Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

NASA Astrophysics Data System (ADS)

Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

2016-03-01

Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

First Global Analysis of Saturation Artifacts in the VIIRS Infrared Channels and the Effects of Detector Aggregation

NASA Astrophysics Data System (ADS)

Wang, J.; Polivka, T. N.; Hyer, E. J.; Peterson, D. A.

2014-12-01

Unlike previous space-borne Earth-observing sensors, the Visible Infrared Imaging Radiometer Suite (VIIRS) employs aggregation to reduce downlink bandwidth requirements and preserve spatial resolution across the swath. To examine the potentially deleterious impacts of aggregation when encountering detector saturation, nearly four months of NOAA's Nightfire product were analyzed, which contains a subset of the hottest observed nighttime pixels. An empirical method for identifying saturation was devised. The 3.69 µm band (M12) was the most frequently-saturating band with 0.15% of the Nightfire pixels at or near the ~359 K hard saturation limit, with possible saturation also occurring in M14, M15, and M16. Artifacts consistent with detector saturation were seen with M12 temperatures as low as 330 K in the scene center. This partial saturation and aggregation influence must be considered when using VIIRS radiances for quantitative characterization of hot emission sources such as fires and gas flaring.

Development and testing of the EVS 2000 enhanced vision system

NASA Astrophysics Data System (ADS)

Way, Scott P.; Kerr, Richard; Imamura, Joe J.; Arnoldy, Dan; Zeylmaker, Richard; Zuro, Greg

2003-09-01

An effective enhanced vision system must operate over a broad spectral range in order to offer a pilot an optimized scene that includes runway background as well as airport lighting and aircraft operations. The large dynamic range of intensities of these images is best handled with separate imaging sensors. The EVS 2000 is a patented dual-band Infrared Enhanced Vision System (EVS) utilizing image fusion concepts to provide a single image from uncooled infrared imagers in both the LWIR and SWIR. The system is designed to provide commercial and corporate airline pilots with improved situational awareness at night and in degraded weather conditions. A prototype of this system was recently fabricated and flown on the Boeing Advanced Technology Demonstrator 737-900 aircraft. This paper will discuss the current EVS 2000 concept, show results taken from the Boeing Advanced Technology Demonstrator program, and discuss future plans for EVS systems.

Non-invasive detection of superimposed latent fingerprints and inter-ridge trace evidence by infrared spectroscopic imaging.

PubMed

Bhargava, Rohit; Perlman, Rebecca Schwartz; Fernandez, Daniel C; Levin, Ira W; Bartick, Edward G

2009-08-01

Current latent print and trace evidence collecting technologies are usually invasive and can be destructive to the original deposits. We describe a non-invasive vibrational spectroscopic approach that yields latent fingerprints that are overlaid on top of one another or that may contain trace evidence that needs to be distinguished from the print. Because of the variation in the chemical composition distribution within the fingerprint, we demonstrate that linear unmixing applied to the spectral content of the data can be used to provide images that reveal superimposed fingerprints. In addition, we demonstrate that the chemical composition of the trace evidence located in the region of the print can potentially be identified by its infrared spectrum. Thus, trace evidence found at a crime scene that previously could not be directly related to an individual, now has the potential to be directly related by its presence in the individual-identifying fingerprints.

Pattern recognition analysis of polar clouds during summer and winter

NASA Technical Reports Server (NTRS)

Ebert, Elizabeth E.

1992-01-01

A pattern recognition algorithm is demonstrated which classifies eighteen surface and cloud types in high-latitude AVHRR imagery based on several spectral and textural features, then estimates the cloud properties (fractional coverage, albedo, and brightness temperature) using a hybrid histogram and spatial coherence technique. The summertime version of the algorithm uses both visible and infrared data (AVHRR channels 1-4), while the wintertime version uses only infrared data (AVHRR channels 3-5). Three days of low-resolution AVHRR imagery from the Arctic and Antarctic during January and July 1984 were analyzed for cloud type and fractional coverage. The analysis showed significant amounts of high cloudiness in the Arctic during one day in winter. The Antarctic summer scene was characterized by heavy cloud cover in the southern ocean and relatively clear conditions in the continental interior. A large region of extremely low brightness temperatures in East Antarctica during winter suggests the presence of polar stratospheric cloud.

Implementation of density functional theory method on object-oriented programming (C++) to calculate energy band structure using the projector augmented wave (PAW)

NASA Astrophysics Data System (ADS)

Alfianto, E.; Rusydi, F.; Aisyah, N. D.; Fadilla, R. N.; Dipojono, H. K.; Martoprawiro, M. A.

2017-05-01

This study implemented DFT method into the C++ programming language with object-oriented programming rules (expressive software). The use of expressive software results in getting a simple programming structure, which is similar to mathematical formula. This will facilitate the scientific community to develop the software. We validate our software by calculating the energy band structure of Silica, Carbon, and Germanium with FCC structure using the Projector Augmented Wave (PAW) method then compare the results to Quantum Espresso calculation’s results. This study shows that the accuracy of the software is 85% compared to Quantum Espresso.

Human speckle perception threshold for still images from a laser projection system.

PubMed

Roelandt, Stijn; Meuret, Youri; Jacobs, An; Willaert, Koen; Janssens, Peter; Thienpont, Hugo; Verschaffelt, Guy

2014-10-06

We study the perception of speckle by human observers in a laser projector based on a 40 persons survey. The speckle contrast is first objectively measured making use of a well-defined speckle measurement method. We statistically analyse the results of the user quality scores, revealing that the speckle perception is not only influenced by the speckle contrast settings of the projector, but it is also strongly influenced by the type of image shown. Based on the survey, we derive a speckle contrast threshold for which speckle can be seen, and separately we investigate a speckle disturbance limit that is tolerated by the majority of test persons.

Infrared radiation scene generation of stars and planets in celestial background

NASA Astrophysics Data System (ADS)

Guo, Feng; Hong, Yaohui; Xu, Xiaojian

2014-10-01

An infrared (IR) radiation generation model of stars and planets in celestial background is proposed in this paper. Cohen's spectral template1 is modified for high spectral resolution and accuracy. Based on the improved spectral template for stars and the blackbody assumption for planets, an IR radiation model is developed which is able to generate the celestial IR background for stars and planets appearing in sensor's field of view (FOV) for specified observing date and time, location, viewpoint and spectral band over 1.2μm ~ 35μm. In the current model, the initial locations of stars are calculated based on midcourse space experiment (MSX) IR astronomical catalogue (MSX-IRAC) 2 , while the initial locations of planets are calculated using secular variations of the planetary orbits (VSOP) theory. Simulation results show that the new IR radiation model has higher resolution and accuracy than common model.

Noise-cancellation-based nonuniformity correction algorithm for infrared focal-plane arrays.

PubMed

Godoy, Sebastián E; Pezoa, Jorge E; Torres, Sergio N

2008-10-10

The spatial fixed-pattern noise (FPN) inherently generated in infrared (IR) imaging systems compromises severely the quality of the acquired imagery, even making such images inappropriate for some applications. The FPN refers to the inability of the photodetectors in the focal-plane array to render a uniform output image when a uniform-intensity scene is being imaged. We present a noise-cancellation-based algorithm that compensates for the additive component of the FPN. The proposed method relies on the assumption that a source of noise correlated to the additive FPN is available to the IR camera. An important feature of the algorithm is that all the calculations are reduced to a simple equation, which allows for the bias compensation of the raw imagery. The algorithm performance is tested using real IR image sequences and is compared to some classical methodologies. (c) 2008 Optical Society of America

Local structure preserving sparse coding for infrared target recognition

PubMed Central

Han, Jing; Yue, Jiang; Zhang, Yi; Bai, Lianfa

2017-01-01

Sparse coding performs well in image classification. However, robust target recognition requires a lot of comprehensive template images and the sparse learning process is complex. We incorporate sparsity into a template matching concept to construct a local sparse structure matching (LSSM) model for general infrared target recognition. A local structure preserving sparse coding (LSPSc) formulation is proposed to simultaneously preserve the local sparse and structural information of objects. By adding a spatial local structure constraint into the classical sparse coding algorithm, LSPSc can improve the stability of sparse representation for targets and inhibit background interference in infrared images. Furthermore, a kernel LSPSc (K-LSPSc) formulation is proposed, which extends LSPSc to the kernel space to weaken the influence of the linear structure constraint in nonlinear natural data. Because of the anti-interference and fault-tolerant capabilities, both LSPSc- and K-LSPSc-based LSSM can implement target identification based on a simple template set, which just needs several images containing enough local sparse structures to learn a sufficient sparse structure dictionary of a target class. Specifically, this LSSM approach has stable performance in the target detection with scene, shape and occlusions variations. High performance is demonstrated on several datasets, indicating robust infrared target recognition in diverse environments and imaging conditions. PMID:28323824

Evaluation of data thinning strategies for climate applications using the first four years of AIRS hyperspectral data

NASA Astrophysics Data System (ADS)

Aumann, Hartmut H.; Fishbein, Evan; Gohlke, Jan

2007-09-01

The application of infrared hyper-spectral sounder data to climate research requires the global analysis of multi-decadal time series of various atmosphere, surface or cloud related parameters. The data used in this analysis has to meet stringent global and scene independent absolute accuracy and stability requirements, it also has to be spatially and radiometrically unbiased, manageable in size and self-contained. Self-contained means that the data set contains not only a globally unbiased sample of the state of the Earth Climate system as seen in the infrared, it has to contain enough data to contrast clear with average (cloudy) data and to allow an independent assessment of the radiometric and spectral accuracy and stability of the data. We illustrate this with data from the Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounder Interferometer (IASI) data. AIRS and IASI were designed with fairly similar functional requirements. AIRS was launched on the EOS Aqua spacecraft in May 2002 into a 705 km polar sun-synchronous orbit with accurately maintained 1:30 PM ascending node. Essentially un-interrupted data are available since September 2002. Since October 2006 IASI is in a 9:30 AM polar orbit at 815 km altitude on the MetOp2 satellite, with data available since May 2007.

Laser scatter feature of surface defect on apples

NASA Astrophysics Data System (ADS)

Rao, Xiuqin; Ying, Yibin; Cen, YiKe; Huang, Haibo

2006-10-01

A machine vision system for real-time fruit quality inspection was developed. The system consists of a chamber, a laser projector, a TMS-7DSP CCD camera (PULNIX Inc.), and a computer. A Meteor-II/MC frame grabber (Matrox Graphics Inc.) was inserted into the slot of the computer to grab fruit images. The laser projector and the camera were mounted at the ceiling of the chamber. An apple was put in the chamber, the spot of the laser projector was projected on the surface of the fruit, and an image was grabbed. 2 breed of apples was test, Each apple was imaged twice, one was imaged for the normal surface, and the other for the defect. The red component of the images was used to get the feature of the defect and the sound surface of the fruits. The average value, STD value and comentropy Value of red component of the laser scatter image were analyzed. The Standard Deviation value of red component of normal is more suitable to separate the defect surface from sound surface for the ShuijinFuji apples, but for bintang apples, there is more work need to do to separate the different surface with laser scatter image.

Recent progress in liquid crystal projection displays

NASA Astrophysics Data System (ADS)

Hamada, Hiroshi

1997-05-01

An LC-projector usually contains 3 monochrome TFT-LCDs with a 3-channel dichroic system or a single TFT-LCD with a micro color filter. The liquid crystal operation mode adopted in a TFT-LCD is TN. The optical throughput of an LC-projector is reduced by a pair of polarizers, an aperture ratio of a TFT- LCD and a color filter in a single-LCD projector. In order to eliminate absorption loss by a color filter, a single LCD projection system which consists of a monochrome LCD with a microlens array and a color splitting system using tilted dichroic mirrors or another optical element such as a holographic optical element or a blazed grating has been developed. And LC rear projection TVs have started to challenge CRT-based rear projection TVs. In addition to this system, new technologies to improve optical throughput have been developed to the practical stage such as an active- matrix-addressed PDLC and a reflective type LCD on a Si-LSI chip. Merits and technical issues of newly developed systems and conventional systems including a-Si TFT-LCDs and p-Si TFT-LCDs are discussed mainly in terms of optical throughput.

Limitations of contrast enhancement for infrared target identification

NASA Astrophysics Data System (ADS)

Du Bosq, Todd W.; Fanning, Jonathan D.

2009-05-01

Contrast enhancement and dynamic range compression are currently being used to improve the performance of infrared imagers by increasing the contrast between the target and the scene content. Automatic contrast enhancement techniques do not always achieve this improvement. In some cases, the contrast can increase to a level of target saturation. This paper assesses the range-performance effects of contrast enhancement for target identification as a function of image saturation. Human perception experiments were performed to determine field performance using contrast enhancement on the U.S. Army RDECOM CERDEC NVESD standard military eight target set using an un-cooled LWIR camera. The experiments compare the identification performance of observers viewing contrast enhancement processed images at various levels of saturation. Contrast enhancement is modeled in the U.S. Army thermal target acquisition model (NVThermIP) by changing the scene contrast temperature. The model predicts improved performance based on any improved target contrast, regardless of specific feature saturation or enhancement. The measured results follow the predicted performance based on the target task difficulty metric used in NVThermIP for the non-saturated cases. The saturated images reduce the information contained in the target and performance suffers. The model treats the contrast of the target as uniform over spatial frequency. As the contrast is enhanced, the model assumes that the contrast is enhanced uniformly over the spatial frequencies. After saturation, the spatial cues that differentiate one tank from another are located in a limited band of spatial frequencies. A frequency dependent treatment of target contrast is needed to predict performance of over-processed images.

Thermal monitoring of hydrothermal activity by permanent infrared automatic stations: Results obtained at Solfatara di Pozzuoli, Campi Flegrei (Italy)

NASA Astrophysics Data System (ADS)

Chiodini, G.; Vilardo, G.; Augusti, V.; Granieri, D.; Caliro, S.; Minopoli, C.; Terranova, C.

2007-12-01

A permanent automatic infrared (IR) station was installed at Solfatara crater, the most active zone of Campi Flegrei caldera. After a positive in situ calibration of the IR camera, we analyze 2175 thermal IR images of the same scene from 2004 to 2007. The scene includes a portion of the steam heated hot soils of Solfatara. The experiment was initiated to detect and quantify temperature changes of the shallow thermal structure of a quiescent volcano such as Solfatara over long periods. Ambient temperature is the main parameter affecting IR temperatures, while air humidity and rain control image quality. A geometric correction of the images was necessary to remove the effects of slow movement of the camera. After a suitable correction the images give a reliable and detailed picture of the temperature changes, over the period October 2004 to January 2007, which suggests that origin of the changes were linked to anthropogenic activity, vegetation growth, and the increase of the flux of hydrothermal fluids in the area of the hottest fumaroles. Two positive temperature anomalies were registered after the occurrence of two seismic swarms which affected the hydrothermal system of Solfatara in October 2005 and October 2006. It is worth noting that these signs were detected in a system characterized by a low level of activity with respect to systems affected by real volcanic crisis where more spectacular results will be expected. Results of the experiment show that this kind of monitoring system can be a suitable tool for volcanic surveillance.

Three-Dimensional Large Screen Display Using Polymer-Dispersed Liquid-Crystal Light Valves and a Schlieren Optical System: Proposal and Basic Experiments

NASA Astrophysics Data System (ADS)

Takizawa, Kuniharu

A novel three-dimensional (3-D) projection display used with polarized eyeglasses is proposed. It consists of polymer-dispersed liquid crystal-light valves that modulate the illuminated light based on light scattering, a polarization beam splitter, and a Schlieren projection system. The features of the proposed display include a 3-D image display with a single projector, half size and half power consumption compared with a conventional 3-D projector with polarized glasses. Measured electro-optic characteristics of a polymer-dispersed liquid-crystal cell inserted between crossed polarizers suggests that the proposed display achieves small cross talk and high-extinction ratio.

Development and validation of the AFIT scene and sensor emulator for testing (ASSET)

NASA Astrophysics Data System (ADS)

Young, Shannon R.; Steward, Bryan J.; Gross, Kevin C.

2017-05-01

ASSET is a physics-based model used to generate synthetic data sets of wide field of view (WFOV) electro-optical and infrared (EO/IR) sensors with realistic radiometric properties, noise characteristics, and sensor artifacts. It was developed to meet the need for applications where precise knowledge of the underlying truth is required but is impractical to obtain for real sensors. For example, due to accelerating advances in imaging technology, the volume of data available from WFOV EO/IR sensors has drastically increased over the past several decades, and as a result, there is a need for fast, robust, automatic detection and tracking algorithms. Evaluation of these algorithms is difficult for objects that traverse a wide area (100-10,000 km) because obtaining accurate truth for the full object trajectory often requires costly instrumentation. Additionally, tracking and detection algorithms perform differently depending on factors such as the object kinematics, environment, and sensor configuration. A variety of truth data sets spanning these parameters are needed for thorough testing, which is often cost prohibitive. The use of synthetic data sets for algorithm development allows for full control of scene parameters with full knowledge of truth. However, in order for analysis using synthetic data to be meaningful, the data must be truly representative of real sensor collections. ASSET aims to provide a means of generating such representative data sets for WFOV sensors operating in the visible through thermal infrared. The work reported here describes the ASSET model, as well as provides validation results from comparisons to laboratory imagers and satellite data (e.g. Landsat-8).

The thermal background determines how the infrared and visual systems interact in pit vipers.

PubMed

Chen, Qin; Liu, Yang; Brauth, Steven E; Fang, Guangzhan; Tang, Yezhong

2017-09-01

The thermal infrared (IR) sensing system of pit vipers is believed to complement vision and provide a substitute imaging system in dark environments. Theoretically, the IR system would best image a scene consisting of a homothermal target in cold surroundings as a bright spot on a dark background. To test this hypothesis, we evaluated how the pit viper ( Gloydius brevicaudus ) discriminates and strikes prey when the background temperature is either higher or lower than that of the prey (approximately 32-33°C) in different parts of the scene. Snakes were tested in a modified predation cage in which background temperatures were set to 26°C on one side and either 33 or 40°C on the opposite side when the eyes, the pit organs or neither sensory system was occluded. When the eyes were blocked, snakes preferred to strike prey on the 26°C side rather than on the 33°C side but showed no bias in the other conditions. Snakes showed no preference for 26 versus 40°C background temperature, although more missed strikes occurred when the eyes were occluded. The results thus revealed that the pit viper IR system can accomplish a 'brightness constancy' computation reflecting the difference between the target and background temperatures, much as the visual system compares the luminance of a figure and the background. Furthermore, the results show that the IR system performs less well for locating prey when the background is warmer than the target. © 2017. Published by The Company of Biologists Ltd.

Scanning laser beam displays based on a 2D MEMS

NASA Astrophysics Data System (ADS)

Niesten, Maarten; Masood, Taha; Miller, Josh; Tauscher, Jason

2010-05-01

The combination of laser light sources and MEMS technology enables a range of display systems such as ultra small projectors for mobile devices, head-up displays for vehicles, wearable near-eye displays and projection systems for 3D imaging. Images are created by scanning red, green and blue lasers horizontally and vertically with a single two-dimensional MEMS. Due to the excellent beam quality of laser beams, the optical designs are efficient and compact. In addition, the laser illumination enables saturated display colors that are desirable for augmented reality applications where a virtual image is used. With this technology, the smallest projector engine for high volume manufacturing to date has been developed. This projector module has a height of 7 mm and a volume of 5 cc. The resolution of this projector is WVGA. No additional projection optics is required, resulting in an infinite focus depth. Unlike with micro-display projection displays, an increase in resolution will not lead to an increase in size or a decrease in efficiency. Therefore future projectors can be developed that combine a higher resolution in an even smaller and thinner form factor with increased efficiencies that will lead to lower power consumption.

Modeling the effects of contrast enhancement on target acquisition performance

NASA Astrophysics Data System (ADS)

Du Bosq, Todd W.; Fanning, Jonathan D.

2008-04-01

Contrast enhancement and dynamic range compression are currently being used to improve the performance of infrared imagers by increasing the contrast between the target and the scene content, by better utilizing the available gray levels either globally or locally. This paper assesses the range-performance effects of various contrast enhancement algorithms for target identification with well contrasted vehicles. Human perception experiments were performed to determine field performance using contrast enhancement on the U.S. Army RDECOM CERDEC NVESD standard military eight target set using an un-cooled LWIR camera. The experiments compare the identification performance of observers viewing linearly scaled images and various contrast enhancement processed images. Contrast enhancement is modeled in the US Army thermal target acquisition model (NVThermIP) by changing the scene contrast temperature. The model predicts improved performance based on any improved target contrast, regardless of feature saturation or enhancement. To account for the equivalent blur associated with each contrast enhancement algorithm, an additional effective MTF was calculated and added to the model. The measured results are compared with the predicted performance based on the target task difficulty metric used in NVThermIP.

Martian Rocks Lining Possible Ancient Channel (Enhanced Color)

NASA Image and Video Library

2017-06-23

NASA's Mars Exploration Rover Opportunity took the component images of this enhanced-color scene during the mission's "walkabout" survey of an area just above the top of "Perseverance Valley," in preparation for driving down the valley. The location is just outside the crest line of the western rim of Endeavour Crater, looking toward the northwest. The rim crest at the top of Perseverance Valley is off the scene to the right. A swath across the top half of the image is lined with dark rocks, especially on the far side. The swath runs east-west, and one possible history under investigation is that it was a channel into a lake perched against the edge of the crater billions of years ago. Another hypothesis is that the linear pattern of the rock piles is related to radial fractures from the impact that excavated Endeavour Crater. One goal of the walkabout is to determine whether a close look at the rocks will provide clues to the history of the site. For scale, the width of the swath near the center of the image is roughly 30 feet (9 meters). Opportunity's panoramic camera (Pancam) recorded this scene on June 3, 2017, during the 4,749th Martian day, or sol, of the rover's work on Mars. The enhanced color helps make differences in surface materials visible. The view merges exposures taken through three of the Pancam's color filters, centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet). https://photojournal.jpl.nasa.gov/catalog/PIA21711

Mars Rover Opportunity Panorama of Wharton Ridge

NASA Image and Video Library

2016-10-07

This scene from NASA's Mars Exploration Rover Opportunity shows "Wharton Ridge," which forms part of the southern wall of "Marathon Valley" on the western rim of Endeavour Crater. The full extent of Wharton Ridge is visible, with the floor of Endeavour Crater beyond it and the far wall of the crater in the distant background. Near the right edge of the scene is "Lewis and Clark Gap," through which Opportunity crossed from Marathon Valley to "Bitterroot Valley" in September 2016. Before the rover departed Marathon Valley, its panoramic camera (Pancam) acquired the component images for this scene on Aug. 30, 2016, during the 4,480th Martian day, or sol, of Opportunity's work on Mars. Opportunity's science team chose the ridge's name to honor the memory of Robert A. Wharton (1951-2012), an astrobiologist who was a pioneer in the use of terrestrial analog environments, particularly in Antarctica, to study scientific problems connected to the habitability of Mars. Over the course of his career, he was a visiting senior scientist at NASA Headquarters, vice president for research at the Desert Research Institute, provost at Idaho State University, and president of the South Dakota School of Mines and Technology. The view spans from east-northeast at left to southeast at right. It merges exposures taken through three of the Pancam's color filters, centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet). It is presented in approximately true color. http://photojournal.jpl.nasa.gov/catalog/PIA20849

Dense depth maps from correspondences derived from perceived motion

NASA Astrophysics Data System (ADS)

Kirby, Richard; Whitaker, Ross

2017-01-01

Many computer vision applications require finding corresponding points between images and using the corresponding points to estimate disparity. Today's correspondence finding algorithms primarily use image features or pixel intensities common between image pairs. Some 3-D computer vision applications, however, do not produce the desired results using correspondences derived from image features or pixel intensities. Two examples are the multimodal camera rig and the center region of a coaxial camera rig. We present an image correspondence finding technique that aligns pairs of image sequences using optical flow fields. The optical flow fields provide information about the structure and motion of the scene, which are not available in still images but can be used in image alignment. We apply the technique to a dual focal length stereo camera rig consisting of a visible light-infrared camera pair and to a coaxial camera rig. We test our method on real image sequences and compare our results with the state-of-the-art multimodal and structure from motion (SfM) algorithms. Our method produces more accurate depth and scene velocity reconstruction estimates than the state-of-the-art multimodal and SfM algorithms.

Control of vertical posture while elevating one foot to avoid a real or virtual obstacle.

PubMed

Ida, Hirofumi; Mohapatra, Sambit; Aruin, Alexander

2017-06-01

The purpose of this study is to investigate the control of vertical posture during obstacle avoidance in a real versus a virtual reality (VR) environment. Ten healthy participants stood upright and lifted one leg to avoid colliding with a real obstacle sliding on the floor toward a participant and with its virtual image. Virtual obstacles were delivered by a head mounted display (HMD) or a 3D projector. The acceleration of the foot, center of pressure, and electrical activity of the leg and trunk muscles were measured and analyzed during the time intervals typical for early postural adjustments (EPAs), anticipatory postural adjustments (APAs), and compensatory postural adjustments (CPAs). The results showed that the peak acceleration of foot elevation in the HMD condition decreased significantly when compared with that of the real and 3D projector conditions. Reduced activity of the leg and trunk muscles was seen when dealing with virtual obstacles (HMD and 3D projector) as compared with that seen when dealing with real obstacles. These effects were more pronounced during APAs and CPAs. The onsets of muscle activities in the supporting limb were seen during EPAs and APAs. The observed modulation of muscle activity and altered patterns of movement seen while avoiding a virtual obstacle should be considered when designing virtual rehabilitation protocols.

Diversity in Mawrth Region, Mars

NASA Technical Reports Server (NTRS)

2006-01-01

This view shows diverse materials and morphologies in the region south of Mawrth Vallis on Mars. The color is composed of infrared, red, and blue-green color images, and has been enhanced to accentuate the color differences. The bright material may be rich in clays and date back to a time when Mars had a wetter environment. This is a sub-image of a larger view imaged by the High Resolution Imaging Science Experiment (HiRISE) on NASA's Mars Reconnaissance Orbiter on Oct. 1, 2006. The resolution is 25 centimeters (10 inches) per pixel, and the scene is 352 meters (385 yards) wide.

Land use classification utilizing remote multispectral scanner data and computer analysis techniques

NASA Technical Reports Server (NTRS)

Leblanc, P. N.; Johannsen, C. J.; Yanner, J. E.

1973-01-01

An airborne multispectral scanner was used to collect the visible and reflective infrared data. A small subdivision near Lafayette, Indiana was selected as the test site for the urban land use study. Multispectral scanner data were collected over the subdivision on May 1, 1970 from an altitude of 915 meters. The data were collected in twelve wavelength bands from 0.40 to 1.00 micrometers by the scanner. The results indicated that computer analysis of multispectral data can be very accurate in classifying and estimating the natural and man-made materials that characterize land uses in an urban scene.

Applying AR technology with a projector-camera system in a history museum

NASA Astrophysics Data System (ADS)

Miyata, Kimiyoshi; Shiroishi, Rina; Inoue, Yuka

2011-01-01

In this research, an AR (augmented reality) technology with projector-camera system is proposed for a history museum to provide user-friendly interface and pseudo hands-on exhibition. The proposed system is a desktop application and designed for old Japanese coins to enhance the visitors' interests and motivation to investigate them. The size of the old coins are small to recognize their features and the surface of the coins has fine structures on both sides, so it is meaningful to show the reverse side and enlarged image of the coins to the visitors for enhancing their interest and motivation. The image of the reverse side of the coins is displayed based on the AR technology to reverse the AR marker by the user. The information to augment the coins is projected by using a data projector, and the information is placed nearby the coins. The proposed system contributes to develop an exhibition method based on the combinations of the real artifacts and the AR technology, and demonstrated the flexibility and capability to offer background information relating to the old Japanese coins. However, the accuracy of the detection and tracking of the markers and visitor evaluation survey are required to improve the effectiveness of the system.

An Analysis of the Max-Min Texture Measure.

DTIC Science & Technology

1982-01-01

PANC 33 D2 Confusion Matrices for Scene A, IR 34 D3 Confusion Matrices for Scene B, PANC 35 D4 Confusion Matrices for Scene B, IR 36 D5 Confusion...Matrices for Scene C, PANC 37 D6 Confusion Matrices for Scene C, IR 38 D7 Confusion Matrices for Scene E, PANC 39 D8 Confusion Matrices for Scene E, IR 40...D9 Confusion Matrices for Scene H, PANC 41 DIO Confusion Matrices for Scene H, JR 42 3 .D 10CnuinMtie o cn ,IR4 AN ANALYSIS OF THE MAX-MIN TEXTURE

Test set up description and performances for HAWAII-2RG detector characterization at ESTEC

NASA Astrophysics Data System (ADS)

Crouzet, P.-E.; ter Haar, J.; de Wit, F.; Beaufort, T.; Butler, B.; Smit, H.; van der Luijt, C.; Martin, D.

2012-07-01

In the frame work of the European Space Agency's Cosmic Vision program, the Euclid mission has the objective to map the geometry of the Dark Universe. Galaxies and clusters of galaxies will be observed in the visible and near-infrared wavelengths by an imaging and spectroscopic channel. For the Near Infrared Spectrometer instrument (NISP), the state-of-the-art HAWAII-2RG detectors will be used, associated with the SIDECAR ASIC readout electronic which will perform the image frame acquisitions. To characterize and validate the performance of these detectors, a test bench has been designed, tested and validated. This publication describes the pre-tests performed to build the set up dedicated to dark current measurements and tests requiring reasonably uniform light levels (such as for conversion gain measurements). Successful cryogenic and vacuum tests on commercial LEDs and photodiodes are shown. An optimized feed through in stainless steel with a V-groove to pot the flex cable connecting the SIDECAR ASIC to the room temperature board (JADE2) has been designed and tested. The test set up for quantum efficiency measurements consisting of a lamp, a monochromator, an integrating sphere and set of cold filters, and which is currently under construction will ensure a uniform illumination across the detector with variations lower than 2%. A dedicated spot projector for intra-pixel measurements has been designed and built to reach a spot diameter of 5 μm at 920nm with 2nm of bandwidth [1].

Projection type transparent 3D display using active screen

NASA Astrophysics Data System (ADS)

Kamoshita, Hiroki; Yendo, Tomohiro

2015-05-01

Equipment to enjoy a 3D image, such as a movie theater, television and so on have been developed many. So 3D video are widely known as a familiar image of technology now. The display representing the 3D image are there such as eyewear, naked-eye, the HMD-type, etc. They has been used for different applications and location. But have not been widely studied for the transparent 3D display. If transparent large 3D display is realized, it is useful to display 3D image overlaid on real scene in some applications such as road sign, shop window, screen in the conference room etc. As a previous study, to produce a transparent 3D display by using a special transparent screen and number of projectors is proposed. However, for smooth motion parallax, many projectors are required. In this paper, we propose a display that has transparency and large display area by time multiplexing projection image in time-division from one or small number of projectors to active screen. The active screen is composed of a number of vertically-long small rotate mirrors. It is possible to realize the stereoscopic viewing by changing the image of the projector in synchronism with the scanning of the beam.3D vision can be realized by light is scanned. Also, the display has transparency, because it is possible to see through the display when the mirror becomes perpendicular to the viewer. We confirmed the validity of the proposed method by using simulation.

VIIRS thermal emissive bands on-orbit calibration coefficient performance using vicarious calibration results

NASA Astrophysics Data System (ADS)

Moyer, D.; Moeller, C.; De Luccia, F.

2013-09-01

The Visible Infrared Imager Radiometer Suite (VIIRS), a primary sensor on-board the Suomi-National Polar-orbiting Partnership (SNPP) spacecraft, was launched October 28, 2011. It has 22 bands: 7 thermal emissive bands (TEBs), 14 reflective solar bands (RSBs) and a Day Night Band (DNB). The TEBs cover the spectral wavelengths between 3.7 to 12 μm and have two 371 m and five 742 m spatial resolution bands. A VIIRS Key Performance Parameter (KPP) is the sea surface temperature (SST) which uses bands M12 (3.7 μm), M15 (10.8 μm) and M16's (12.0 μm) calibrated Science Data Records (SDRs). The TEB SDRs rely on pre-launch calibration coefficients used in a quadratic algorithm to convert the detector's response to calibrated radiance. This paper will evaluate the performance of these prelaunch calibration coefficients using vicarious calibration information from the Cross-track Infrared Sounder (CrIS) also onboard the SNPP spacecraft and the Infrared Atmospheric Sounding Interferometer (IASI) on-board the Meteorological Operational (MetOp) satellite. Changes to the pre-launch calibration coefficients' offset term c0 to improve the SDR's performance at cold scene temperatures will also be discussed.

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

Grant, Ashleigh; Wilkinson, T.J.; Holman, Thomas

Analysis of fingerprints has predominantly focused on matching the pattern of ridges to a specific person as a form of identification. The present work focuses on identifying extrinsic materials that are left within a person's fingerprint after recent handling of such materials. Specifically, we employed infrared spectromicroscopy to locate and positively identify microscopic particles from a mixture of common materials in the latent human fingerprints of volunteer subjects. We were able to find and correctly identify all test substances based on their unique infrared spectral signatures. Spectral imaging is demonstrated as a method for automating recognition of specific substances inmore » a fingerprint. We also demonstrate the use of Attenuated Total Reflectance (ATR) and synchrotron-based infrared spectromicroscopy for obtaining high-quality spectra from particles that were too thick or too small, respectively, for reflection/absorption measurements. We believe the application of this rapid, non-destructive analytical technique to the forensic study of latent human finger prints has the potential to add a new layer of information available to investigators. Using fingerprints to not only identify who was present at a crime scene, but also to link who was handling key materials will be a powerful investigative tool.« less

Background Characterization Techniques For Pattern Recognition Applications

NASA Astrophysics Data System (ADS)

Noah, Meg A.; Noah, Paul V.; Schroeder, John W.; Kessler, Bernard V.; Chernick, Julian A.

1989-08-01

The Department of Defense has a requirement to investigate technologies for the detection of air and ground vehicles in a clutter environment. The use of autonomous systems using infrared, visible, and millimeter wave detectors has the potential to meet DOD's needs. In general, however, the hard-ware technology (large detector arrays with high sensitivity) has outpaced the development of processing techniques and software. In a complex background scene the "problem" is as much one of clutter rejection as it is target detection. The work described in this paper has investigated a new, and innovative, methodology for background clutter characterization, target detection and target identification. The approach uses multivariate statistical analysis to evaluate a set of image metrics applied to infrared cloud imagery and terrain clutter scenes. The techniques are applied to two distinct problems: the characterization of atmospheric water vapor cloud scenes for the Navy's Infrared Search and Track (IRST) applications to support the Infrared Modeling Measurement and Analysis Program (IRAMMP); and the detection of ground vehicles for the Army's Autonomous Homing Munitions (AHM) problems. This work was sponsored under two separate Small Business Innovative Research (SBIR) programs by the Naval Surface Warfare Center (NSWC), White Oak MD, and the Army Material Systems Analysis Activity at Aberdeen Proving Ground MD. The software described in this paper will be available from the respective contract technical representatives.

Development of an inverse distance weighted active infrared stealth scheme using the repulsive particle swarm optimization algorithm.

PubMed

Han, Kuk-Il; Kim, Do-Hwi; Choi, Jun-Hyuk; Kim, Tae-Kuk

2018-04-20

Treatments for detection by infrared (IR) signals are higher than for other signals such as radar or sonar because an object detected by the IR sensor cannot easily recognize its detection status. Recently, research for actively reducing IR signal has been conducted to control the IR signal by adjusting the surface temperature of the object. In this paper, we propose an active IR stealth algorithm to synchronize IR signals from the object and the background around the object. The proposed method includes the repulsive particle swarm optimization statistical optimization algorithm to estimate the IR stealth surface temperature, which will result in a synchronization between the IR signals from the object and the surrounding background by setting the inverse distance weighted contrast radiant intensity (CRI) equal to zero. We tested the IR stealth performance in mid wavelength infrared (MWIR) and long wavelength infrared (LWIR) bands for a test plate located at three different positions on a forest scene to verify the proposed method. Our results show that the inverse distance weighted active IR stealth technique proposed in this study is proved to be an effective method for reducing the contrast radiant intensity between the object and background up to 32% as compared to the previous method using the CRI determined as the simple signal difference between the object and the background.

Infrared and visible images registration with adaptable local-global feature integration for rail inspection

NASA Astrophysics Data System (ADS)

Tang, Chaoqing; Tian, Gui Yun; Chen, Xiaotian; Wu, Jianbo; Li, Kongjing; Meng, Hongying

2017-12-01

Active thermography provides infrared images that contain sub-surface defect information, while visible images only reveal surface information. Mapping infrared information to visible images offers more comprehensive visualization for decision-making in rail inspection. However, the common information for registration is limited due to different modalities in both local and global level. For example, rail track which has low temperature contrast reveals rich details in visible images, but turns blurry in the infrared counterparts. This paper proposes a registration algorithm called Edge-Guided Speeded-Up-Robust-Features (EG-SURF) to address this issue. Rather than sequentially integrating local and global information in matching stage which suffered from buckets effect, this algorithm adaptively integrates local and global information into a descriptor to gather more common information before matching. This adaptability consists of two facets, an adaptable weighting factor between local and global information, and an adaptable main direction accuracy. The local information is extracted using SURF while the global information is represented by shape context from edges. Meanwhile, in shape context generation process, edges are weighted according to local scale and decomposed into bins using a vector decomposition manner to provide more accurate descriptor. The proposed algorithm is qualitatively and quantitatively validated using eddy current pulsed thermography scene in the experiments. In comparison with other algorithms, better performance has been achieved.

Enhancing the radiology learning experience with electronic whiteboard technology.

PubMed

Lipton, Michael L; Lipton, Leah G

2010-06-01

The purpose of this study is to quantitatively evaluate the use of an interactive whiteboard for use in teaching diagnostic radiology and MRI physics. An interactive whiteboard (SMART Board model 3000i) was used during an MRI physics course and diagnostic radiology teaching conferences. A multiquestion instrument was used to quantify responses. Responses are reported as simple percentages of response number and, for ordinal scale questions, the two-tailed Student's t test was used to assess deviation from the neutral response. All of the subjects attended all sessions and completed the assessment questionnaire; 89% of respondents said that image quality of the SMART Board was superior to that of a projector-screen combination, 11% said that the image quality was similar, and none said that it was inferior. Sixty-seven percent of respondents said that the SMART Board's display of diagrams was superior to that of a conventional whiteboard, 33% said it was similar, and none said it was inferior. Participants thought that the smaller SMART Board display compared with the projector screen was an unimportant limitation (p = 0.03). Room lighting did not degrade image quality (p = 0.007), and a trend toward preference for the lighted room (while using the SMART Board) was detected (p = 0.15) but was not significant. The impact of the SMART Board on the visual material and flow of teaching sessions was favorable (p = 0.005). All of the subjects preferred the SMART Board over a traditional projector and screen combination. Learners endorsed that the SMART Board significantly enhanced learning, universally preferring it to the standard projector and screen approach. Major advantages include enhanced engagement of learners; enhanced integration of images and annotations or diagrams, including display of both images and diagrams simultaneously on a single screen; and the ability to review, revise, save, and distribute diagrams and annotated images. Disadvantages include cost and potentially complicated setup in very large auditoriums.

WE-G-BRA-02: Visual Demonstrations of Medical Physics Concepts of Transmission Imaging for Resident Education.

PubMed

Sechopoulos, I

2012-06-01

To improve the radiology residents' understanding of medical physics concepts through visualization of physical phenomena. Several medical physics concepts in x-ray transmission imaging are relevant to many radiographic modalities, not only to planar radiography. Therefore, it is important that the diagnostic radiology residents obtain a good understanding of these concepts. However, standard PowerPoint slides or blackboard-based graphical representations are not always effective ways to communicate these novel concepts to the residents. To improve upon the understanding of these concepts, the computer, projector and screen in the lecture room are used as surrogates of an x-ray imaging system. The projector is the source of light (x-rays) with PowerPoint slides defining the pattern emitted (x-ray field) on to the projector screen (detector/monitor). Several different transparencies and acrylic objects are used to demonstrate varied medical physics phenomena relevant to transmission imaging, such as: straight-line travel of electromagnetic radiation; tissue superimposition; object, subject, image and display contrast; linear systems; point spread functions; frequency domain; contrast and modulation transfer functions; quantum and image noise; noise frequency and noise power spectrum; anatomical noise; magnification and geometric unsharpness; inverse square distance relationship; sampling and aliasing; and x-ray scatter. The residents' comprehension and ability to explain these concepts has substantially improved, in addition to their interest in these topics. This was reflected on improved test scores and on anonymous feedback surveys post- lectures. The use of demonstrations that mimic the conditions and physical phenomena found in transmission imaging by taking advantage of the projector and screen together with transparencies and other objects improves the residents' grasp of basic radiographic concepts and promotes live interactions between the residents and the medical physicist. Additional concepts that can be demonstrated in this manner are being sought. © 2012 American Association of Physicists in Medicine.

Maiden flight of the infrared sounder GLORIA

NASA Astrophysics Data System (ADS)

Friedl-Vallon, Felix; Gloria-Team

2013-05-01

The Gimballed Limb Radiance Imager of the Atmosphere (GLORIA) instrument is an imaging Fourier transform spectrometer that is capable to operate on various high altitude research aircraft and on stratospheric balloons. The instrument is a joint development of the Helmholtz Centers Jülich and Karlsruhe Institute of Technology. GLORIA has flown for the first time in December 2011 on board the Russian Geophysica M55 research aircraft. Atmospheric measurements with GLORIA are possible in limb and nadir geometry. The scientific focus in limb sounding mode is on dynamics, tropopause region, TTL and polar UTLS. The nadir mode is tailored to processes in the troposphere such as biomass burning events and high precision methane measurements. The combination of limb and nadir will combine good spatial resolution in both the troposphere and lower stratosphere. In addition, GLORIA serves as a proof of concept instrument for the candidate ESA Earth explorer mission PREMIER. The GLORIA spectrometer consists of a classical Michelson interferometer combined with an infrared camera. The spectral range of the first instrument version extends from 780 cm-1 to 1400 cm-1 with a spectral resolution of up to 0.075 cm-1. The high speed HgCdTe focal plane array with 256×256 elements allows in the limb mode an extremely high spatial sampling of up to 100 m in the vertical domain. The spectrometer is mounted in a gimballed frame that permits agility in elevational and azimuthal direction, as well as image rotation. Scene acquisition and scene stabilisation are accomplished by a control system based on an inertial measurement unit. Limb scenes can be chosen within 45° and 132° to the flight direction of the aircraft allowing tomographic analysis of sampled air volumes.

System for Thermal Imaging of Hot Moving Objects

NASA Technical Reports Server (NTRS)

Weinstein, Leonard; Hundley, Jason

2007-01-01

The High Altitude/Re-Entry Vehicle Infrared Imaging (HARVII) system is a portable instrumentation system for tracking and thermal imaging of a possibly distant and moving object. The HARVII is designed specifically for measuring the changing temperature distribution on a space shuttle as it reenters the atmosphere. The HARVII system or other systems based on the design of the HARVII system could also be used for such purposes as determining temperature distributions in fires, on volcanoes, and on surfaces of hot models in wind tunnels. In yet another potential application, the HARVII or a similar system would be used to infer atmospheric pollution levels from images of the Sun acquired at multiple wavelengths over regions of interest. The HARVII system includes the Ratio Intensity Thermography System (RITS) and a tracking subsystem that keeps the RITS aimed at the moving object of interest. The subsystem of primary interest here is the RITS (see figure), which acquires and digitizes images of the same scene at different wavelengths in rapid succession. Assuming that the time interval between successive measurements is short enough that temperatures do not change appreciably, the digitized image data at the different wavelengths are processed to extract temperatures according to the principle of ratio-intensity thermography: The temperature at a given location in a scene is inferred from the ratios between or among intensities of infrared radiation from that location at two or more wavelengths. This principle, based on the Stefan-Boltzmann equation for the intensity of electromagnetic radiation as a function of wavelength and temperature, is valid as long as the observed body is a gray or black body and there is minimal atmospheric absorption of radiation.

[On-orbit radiometric calibration accuracy of FY-3A MERSI thermal infrared channel].

PubMed

Xu, Na; Hu, Xiu-qing; Chen, Lin; Zhang, Yong; Hu, Ju-yang; Sun, Ling

2014-12-01

Accurate satellite radiance measurements are significant for data assimilations and quantitative retrieval applications. In the present paper, radiometric calibration accuracy of FungYun-3A (FY-3A) Medium Resolution Spectral Imager (MERSI) thermal infrared (TIR) channel was evaluated based on simultaneous nadir observation (SNO) intercalibration method. Hyperspectral and high-quality measurements of METOP-A/IASI were used as reference. Assessment uncertainty from intercalibration method was also investigated by examining the relation between BT bias against four main collocation factors, i. e. observation time difference, view geometric difference related to zenith angles and azimuth angles, and scene spatial homogeneity. It was indicated that the BT bias is evenly distributed across the collocation variables with no significant linear relationship in MERSI IR channel. Among the four collocation factors, the scene spatial homogeneity may be the most important factor with the uncertainty less than 2% of BT bias. Statistical analysis of monitoring biases during one and a half years indicates that the brightness temperature measured by MERSI is much warmer than that of IASI. The annual mean bias (MERSI-IASI) in 2012 is (3.18±0.34) K. Monthly averaged BT biases show a little seasonal variation character, and fluctuation range is less than 0.8 K. To further verify the reliability, our evaluation result was also compared with the synchronous experiment results at Dunhuang and Qinghai Lake sites, which showed excellent agreement. Preliminary analysis indicates that there are two reasons leading to the warm bias. One is the overestimation of blackbody emissivity, and the other is probably the incorrect spectral respond function which has shifted to window spectral. Considering the variation character of BT biases, SRF error seems to be the dominant factor.

THEMIS high-resolution digital terrain: Topographic and thermophysical mapping of Gusev Crater, Mars

USGS Publications Warehouse

Cushing, G.E.; Titus, T.N.; Soderblom, L.A.; Kirk, R.L.

2009-01-01

We discuss a new technique to generate high-resolution digital terrain models (DTMs) and to quantitatively derive and map slope-corrected thermophysical properties such as albedo, thermal inertia, and surface temperatures. This investigation is a continuation of work started by Kirk et al. (2005), who empirically deconvolved Thermal Emission Imaging System (THEMIS) visible and thermal infrared data of this area, isolating topographic information that produced an accurate DTM. Surface temperatures change as a function of many variables such as slope, albedo, thermal inertia, time, season, and atmospheric opacity. We constrain each of these variables to construct a DTM and maps of slope-corrected albedo, slope- and albedo-corrected thermal inertia, and surface temperatures across the scene for any time of day or year and at any atmospheric opacity. DTMs greatly facilitate analyses of the Martian surface, and the MOLA global data set is not finely scaled enough (128 pixels per degree, ???0.5 km per pixel near the equator) to be combined with newer data sets (e.g., High Resolution Imaging Science Experiment, Context Camera, and Compact Reconnaissance Imaging Spectrometer for Mars at ???0.25, ???6, and ???20 m per pixel, respectively), so new techniques to derive high-resolution DTMs are always being explored. This paper discusses our technique of combining a set of THEMIS visible and thermal infrared observations such that albedo and thermal inertia variations within the scene are eliminated and only topographic variations remain. This enables us to produce a high-resolution DTM via photoclinometry techniques that are largely free of albedo-induced errors. With this DTM, THEMIS observations, and a subsurface thermal diffusion model, we generate slope-corrected maps of albedo, thermal inertia, and surface temperatures. In addition to greater accuracy, these products allow thermophysical properties to be directly compared with topography.

Can IR scene projectors reduce total system cost?

NASA Astrophysics Data System (ADS)

Ginn, Robert; Solomon, Steven

2006-05-01

There is an incredible amount of system engineering involved in turning the typical infrared system needs of probability of detection, probability of identification, and probability of false alarm into focal plane array (FPA) requirements of noise equivalent irradiance (NEI), modulation transfer function (MTF), fixed pattern noise (FPN), and defective pixels. Unfortunately, there are no analytic solutions to this problem so many approximations and plenty of "seat of the pants" engineering is employed. This leads to conservative specifications, which needlessly drive up system costs by increasing system engineering costs, reducing FPA yields, increasing test costs, increasing rework and the never ending renegotiation of requirements in an effort to rein in costs. These issues do not include the added complexity to the FPA factory manager of trying to meet varied, and changing, requirements for similar products because different customers have made different approximations and flown down different specifications. Scene generation technology may well be mature and cost effective enough to generate considerable overall savings for FPA based systems. We will compare the costs and capabilities of various existing scene generation systems and estimate the potential savings if implemented at several locations in the IR system fabrication cycle. The costs of implementing this new testing methodology will be compared to the probable savings in systems engineering, test, rework, yield improvement and others. The diverse requirements and techniques required for testing missile warning systems, missile seekers, and FLIRs will be defined. Last, we will discuss both the hardware and software requirements necessary to meet the new test paradigm and discuss additional cost improvements related to the incorporation of these technologies.

Demonstrating Forces between Parallel Wires.

ERIC Educational Resources Information Center

Baker, Blane

2000-01-01

Describes a physics demonstration that dramatically illustrates the mutual repulsion (attraction) between parallel conductors using insulated copper wire, wooden dowels, a high direct current power supply, electrical tape, and an overhead projector. (WRM)

Liquid crystal modulator with ultra-wide dynamic range and adjustable driving voltage.

PubMed

Wang, Xing-jun; Huang, Zhang-di; Feng, Jing; Chen, Xiang-fei; Liang, Xiao; Lu, Yan-qing

2008-08-18

We demonstrated a reflective-type liquid crystal (LC) intensity modulator in 1550 nm telecomm band. An effective way to compensate the residual phase of a LC cell is proposed. With the adjustment of a true zero-order quarter wave plate and enhanced by total internal reflection induced birefringence, over 53 dB dynamic range was achieved, which is much desired for some high-end optical communication, infrared scene projection applications. In addition, the driving voltages were decreased and adjustable. Mechanical and spectral tolerance measurements show that our LC modulator is quite stable. Further applications of our experimental setup were discussed including bio-sensors and high speed modulators.

Coniferous Canopy BRF Simulation Based on 3-D Realistic Scene

NASA Technical Reports Server (NTRS)

Wang, Xin-yun; Guo, Zhi-feng; Qin, Wen-han; Sun, Guo-qing

2011-01-01

It is difficulties for the computer simulation method to study radiation regime at large-scale. Simplified coniferous model was investigate d in the present study. It makes the computer simulation methods such as L-systems and radiosity-graphics combined method (RGM) more powerf ul in remote sensing of heterogeneous coniferous forests over a large -scale region. L-systems is applied to render 3-D coniferous forest scenarios: and RGM model was used to calculate BRF (bidirectional refle ctance factor) in visible and near-infrared regions. Results in this study show that in most cases both agreed well. Meanwhiie at a tree and forest level. the results are also good.

Formulation of image quality prediction criteria for the Viking lander camera

NASA Technical Reports Server (NTRS)

Huck, F. O.; Jobson, D. J.; Taylor, E. J.; Wall, S. D.

1973-01-01

Image quality criteria are defined and mathematically formulated for the prediction computer program which is to be developed for the Viking lander imaging experiment. The general objective of broad-band (black and white) imagery to resolve small spatial details and slopes is formulated as the detectability of a right-circular cone with surface properties of the surrounding terrain. The general objective of narrow-band (color and near-infrared) imagery to observe spectral characteristics if formulated as the minimum detectable albedo variation. The general goal to encompass, but not exceed, the range of the scene radiance distribution within single, commandable, camera dynamic range setting is also considered.

Determination of cloud fields from analysis of HIRS2/MSU sounding data. [20 channel infrared and 4 channel microwave atmospheric sounders

NASA Technical Reports Server (NTRS)

Susskind, J.; Reuter, D.

1986-01-01

IR and microwave remote sensing data collected with the HIRS2 and MSU sensors on the NOAA polar-orbiting satellites were evaluated for their effectiveness as bases for determining the cloud cover and cloud physical characteristics. Techniques employed to adjust for day-night alterations in the radiance fields are described, along with computational procedures applied to compare scene pixel values with reference values for clear skies. Sample results are provided for the mean cloud coverage detected over South America and Africa June 1979, with attention given to concurrent surface pressure and cloud top pressure values.

Estimating chlorophyll content and bathymetry of Lake Tahoe using AVIRIS data

NASA Technical Reports Server (NTRS)

Hamilton, Michael K.; Davis, Curtiss O.; Rhea, W. J.; Pilorz, Stuart H.; Carder, Kendall L.

1993-01-01

Data on chlorophyll content and bathymetry of Lake Tahoe obtained on August 9, 1990 by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) are compared to concurrent in situ surface and in-water measurements. Measured parameters included profiles of percent transmission of monochromatic light, stimulated chlorophyll fluorescence, photosynthetically available radiation, spectral upwelling and downwelling irradiance, and upwelling radiance. Several analyses were performed illustrating the utility of the AVIRIS over a dark water scene. Image-derived chlorophyll concentration compared extremely well with that measured with bottle samples. A bathymetry map of the shallow parts of the lake was constructed which compares favorably with published lake soundings.

Feature diagnosticity and task context shape activity in human scene-selective cortex.

PubMed

Lowe, Matthew X; Gallivan, Jason P; Ferber, Susanne; Cant, Jonathan S

2016-01-15

Scenes are constructed from multiple visual features, yet previous research investigating scene processing has often focused on the contributions of single features in isolation. In the real world, features rarely exist independently of one another and likely converge to inform scene identity in unique ways. Here, we utilize fMRI and pattern classification techniques to examine the interactions between task context (i.e., attend to diagnostic global scene features; texture or layout) and high-level scene attributes (content and spatial boundary) to test the novel hypothesis that scene-selective cortex represents multiple visual features, the importance of which varies according to their diagnostic relevance across scene categories and task demands. Our results show for the first time that scene representations are driven by interactions between multiple visual features and high-level scene attributes. Specifically, univariate analysis of scene-selective cortex revealed that task context and feature diagnosticity shape activity differentially across scene categories. Examination using multivariate decoding methods revealed results consistent with univariate findings, but also evidence for an interaction between high-level scene attributes and diagnostic visual features within scene categories. Critically, these findings suggest visual feature representations are not distributed uniformly across scene categories but are shaped by task context and feature diagnosticity. Thus, we propose that scene-selective cortex constructs a flexible representation of the environment by integrating multiple diagnostically relevant visual features, the nature of which varies according to the particular scene being perceived and the goals of the observer. Copyright © 2015 Elsevier Inc. All rights reserved.

Roughness effects on thermal-infrared emissivities estimated from remotely sensed images

NASA Astrophysics Data System (ADS)

Mushkin, Amit; Danilina, Iryna; Gillespie, Alan R.; Balick, Lee K.; McCabe, Matthew F.

2007-10-01

Multispectral thermal-infrared images from the Mauna Loa caldera in Hawaii, USA are examined to study the effects of surface roughness on remotely retrieved emissivities. We find up to a 3% decrease in spectral contrast in ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) 90-m/pixel emissivities due to sub-pixel surface roughness variations on the caldera floor. A similar decrease in spectral contrast of emissivities extracted from MASTER (MODIS/ASTER Airborne Simulator) ~12.5-m/pixel data can be described as a function of increasing surface roughness, which was measured remotely from ASTER 15-m/pixel stereo images. The ratio between ASTER stereo images provides a measure of sub-pixel surface-roughness variations across the scene. These independent roughness estimates complement a radiosity model designed to quantify the unresolved effects of multiple scattering and differential solar heating due to sub-pixel roughness elements and to compensate for both sub-pixel temperature dispersion and cavity radiation on TIR measurements.

Mid-wave infrared hyperspectral imaging of unknown chemical warfare agents

NASA Astrophysics Data System (ADS)

Clewes, Rhea J.; Howle, Chris R.; Guicheteau, Jason; Emge, Darren; Ruxton, Keith; Robertson, Gordon; Miller, William; Malcolm, Graeme; Maker, Gareth T.

2013-05-01

The ability of a stand-off chemical detector to distinguish two different chemical warfare agents is demonstrated in this paper. Using Negative Contrast Imaging, based upon IR absorption spectroscopy, we were able to detect 1 μl of VX, sulfur mustard and water on a subset of representative surfaces. These experiments were performed at a range of 1.3 metres and an angle of 45° to the surface. The technique employed utilises a Q-switched intracavity MgO:PPLN crystal that generated 1.4 - 1.8 μm (shortwave) and 2.6 - 3.6 μm (midwave) infrared radiation (SWIR and MWIR, respectively). The MgO:PPLN crystal has a fanned grating design which, via translation through a 1064 nm pump beam, enables tuning through the SWIR and MWIR wavelength ranges. The SWIR and MWIR beams are guided across a scene via a pair of raster scanned mirrors allowing detection of absorption features within these spectral regions. This investigation exploited MWIR signatures, as they provided sufficient molecular information to distinguish between toxic and benign chemicals in these proof-of-concept experiments.

Flagstaff, Arizona seen in Earth Resources Experiments package

NASA Image and Video Library

1974-02-01

SL4-93-067 (16 Nov. 1973-8 Feb. 1974) --- A spectacular winter view of the Flagstaff, Arizona area is seen in this Skylab 4 Earth Resources Experiments package S190-B (five-inch earth terrain camera) infrared photograph taken from the Skylab space station in Earth orbit. Included in the scene are the San Francisco Mountains, Oak Creek Canyon, Painted Desert and Meteor Crater. The infrared picture depicts in red living vegetation, in white the snow, and in bright blue the water. Major features identified in this photograph are Humphrey's peak, top center, Flagstaff at foot of the peak, Sunset Crater volcanic field with numerous vents and craters right of Flagstaff and Meteor Crater (right center). Within the mountainous areas several clear areas generally rectangular are visible and represent the areas where lumbering has removed the forest. The thin white line extending from left corner to Sunset Crater fields is the power transmission line cleared area. Roads are subdued and are not easily visible. Photo credit: NASA

Performance and Results from a Space Borne, Uncooled Microbolometer Array Spectral Radiometric Imager

NASA Technical Reports Server (NTRS)

Spinhirne, James M; Scott, V. Stan; Lancaster, Redgie S.; Manizade, Kathrine; Palm, Steven P.

2000-01-01

The Infrared Spectral Imaging Radiometer experiment was flown on a space shuttle mission as a shuttle hitchhiker experiment in August of 1997. The goals of the experiment were to test uncooled array detectors for infrared spectral imaging from space and to apply for the first time retrieval from space of brightness temperatures of cloud, land and sea along with direct laser measurements of cloud top height. The instrument operates in 3 narrow and one broad spectral band, all between 7 and 13 microns in either stare or time-delay and integration mode. The nominal spatial resolution was 1/4 kilometer. Using onboard calibrations along with periodic views of deep space, radiometric calibration of imagery was carried out and performance analyzed. The noise equivalent temperature difference and absolute accuracy reported here varied with operating mode, spectral band and scene temperature but were within requirements. This paper provides a description of the instrument, its operating modes, the method of brightness temperature retrieval, the method of spectral registration and results from the flight.

Fast-responding liquid crystal light-valve technology for color-sequential display applications

NASA Astrophysics Data System (ADS)

Janssen, Peter J.; Konovalov, Victor A.; Muravski, Anatoli A.; Yakovenko, Sergei Y.

1996-04-01

A color sequential projection system has some distinct advantages over conventional systems which make it uniquely suitable for consumer TV as well as high performance professional applications such as computer monitors and electronic cinema. A fast responding light-valve is, clearly, essential for a good performing system. Response speed of transmissive LC lightvalves has been marginal thus far for good color rendition. Recently, Sevchenko Institute has made some very fast reflective LC cells which were evaluated at Philips Labs. These devices showed sub millisecond-large signal-response times, even at room temperature, and produced good color in a projector emulation testbed. In our presentation we describe our highly efficient color sequential projector and demonstrate its operation on video tape. Next we discuss light-valve requirements and reflective light-valve test results.

Spatial uniformity inspection apparatus for solar cells using a projection display.

PubMed

Yoo, Jae-Keun; Kim, Seung Kwan; Lee, Dong-Hoon; Park, Seung-Nam

2012-07-10

We demonstrate a measurement apparatus to inspect spatial uniformity of quantum efficiency of solar cells using a beam projector. Deviation of irradiance from the used beam projector over the area of 1.5×0.8 m on the cell plane was flattened within ±2.6% through gray scale adjustment, which was originally about 200%. Scanning a small square image with an area of 3×3 mm over a square-shaped photovoltaic cell with an area of 15.6×15.6 cm, we could identify the locations according to efficiency level and showed that the cell had quantum efficiency deviation of more than 10%. Utilizing the advantageous feature of a projection display, we also demonstrated that this apparatus can inspect the spatial uniformity of solar modules and panels consisting of multiple solar cells.

Noncommutative de Rham Cohomology of Finite Groups

NASA Astrophysics Data System (ADS)

Castellani, L.; Catenacci, R.; Debernardi, M.; Pagani, C.

We study de Rham cohomology for various differential calculi on finite groups G up to order 8. These include the permutation group S3, the dihedral group D4 and the quaternion group Q. Poincaré duality holds in every case, and under some assumptions (essentially the existence of a top form) we find that it must hold in general. A short review of the bicovariant (noncommutative) differential calculus on finite G is given for selfconsistency. Exterior derivative, exterior product, metric, Hodge dual, connections, torsion, curvature, and biinvariant integration can be defined algebraically. A projector decomposition of the braiding operator is found, and used in constructing the projector on the space of two-forms. By means of the braiding operator and the metric a knot invariant is defined for any finite group.

General review of multispectral cooled IR development at CEA-Leti, France

NASA Astrophysics Data System (ADS)

Boulard, F.; Marmonier, F.; Grangier, C.; Adelmini, L.; Gravrand, O.; Ballet, P.; Baudry, X.; Baylet, J.; Badano, G.; Espiau de Lamaestre, R.; Bisotto, S.

2017-02-01

Multicolor detection capabilities, which bring information on the thermal and chemical composition of the scene, are desirable for advanced infrared (IR) imaging systems. This communication reviews intra and multiband solutions developed at CEA-Leti, from dual-band molecular beam epitaxy grown Mercury Cadmium Telluride (MCT) photodiodes to plasmon-enhanced multicolor IR detectors and backside pixelated filters. Spectral responses, quantum efficiency and detector noise performances, pros and cons regarding global system are discussed in regards to technology maturity, pixel pitch reduction, and affordability. From MWIR-LWIR large band to intra MWIR or LWIR bands peaked detection, results underline the full possibility developed at CEA-Leti.

Nonuniformity correction for an infrared focal plane array based on diamond search block matching.

PubMed

Sheng-Hui, Rong; Hui-Xin, Zhou; Han-Lin, Qin; Rui, Lai; Kun, Qian

2016-05-01

In scene-based nonuniformity correction algorithms, artificial ghosting and image blurring degrade the correction quality severely. In this paper, an improved algorithm based on the diamond search block matching algorithm and the adaptive learning rate is proposed. First, accurate transform pairs between two adjacent frames are estimated by the diamond search block matching algorithm. Then, based on the error between the corresponding transform pairs, the gradient descent algorithm is applied to update correction parameters. During the process of gradient descent, the local standard deviation and a threshold are utilized to control the learning rate to avoid the accumulation of matching error. Finally, the nonuniformity correction would be realized by a linear model with updated correction parameters. The performance of the proposed algorithm is thoroughly studied with four real infrared image sequences. Experimental results indicate that the proposed algorithm can reduce the nonuniformity with less ghosting artifacts in moving areas and can also overcome the problem of image blurring in static areas.

MIRAGE: developments in IRSP systems, RIIC design, emitter fabrication, and performance

NASA Astrophysics Data System (ADS)

Bryant, Paul; Oleson, Jim; James, Jay; McHugh, Steve; Lannon, John; Vellenga, David; Goodwin, Scott; Huffman, Alan; Solomon, Steve; Goldsmith, George C., II

2005-05-01

SBIR's family of MIRAGE infrared scene projection systems is undergoing significant growth and expansion. The first two lots of production IR emitters have completed fabrication at Microelectronics Center of North Carolina/Research and Development Institute (MCNC-RDI), and the next round(s) of emitter production has begun. These latest emitter arrays support programs such as Large Format Resistive Array (LFRA), Optimized Array for Space-based Infrared Simulation (OASIS), MIRAGE 1.5, and MIRAGE II. We present the latest performance data on emitters fabricated at MCNC-RDI, plus integrated system performance on recently completed IRSP systems. Teamed with FLIR Systems/Indigo Operations, SBIR and the Tri-Services IRSP Working Group have completed development of the CMOS Read-In Integrated Circuit (RIIC) portion of the Wide Format Resistive Array (WFRA) program-to extend LFRA performance to a 768 x 1536 "wide screen" projection configuration. WFRA RIIC architecture and performance is presented. Finally, we summarize development of the LFRA Digital Emitter Engine (DEE) and OASIS cryogenic package assemblies, the next-generation Command & Control Electronics (C&CE).

Coniferous canopy BRF simulation based on 3-D realistic scene.

PubMed

Wang, Xin-Yun; Guo, Zhi-Feng; Qin, Wen-Han; Sun, Guo-Qing

2011-09-01

It is difficulties for the computer simulation method to study radiation regime at large-scale. Simplified coniferous model was investigated in the present study. It makes the computer simulation methods such as L-systems and radiosity-graphics combined method (RGM) more powerful in remote sensing of heterogeneous coniferous forests over a large-scale region. L-systems is applied to render 3-D coniferous forest scenarios, and RGM model was used to calculate BRF (bidirectional reflectance factor) in visible and near-infrared regions. Results in this study show that in most cases both agreed well. Meanwhile at a tree and forest level, the results are also good.

Multiscale infrared and visible image fusion using gradient domain guided image filtering

NASA Astrophysics Data System (ADS)

Zhu, Jin; Jin, Weiqi; Li, Li; Han, Zhenghao; Wang, Xia

2018-03-01

For better surveillance with infrared and visible imaging, a novel hybrid multiscale decomposition fusion method using gradient domain guided image filtering (HMSD-GDGF) is proposed in this study. In this method, hybrid multiscale decomposition with guided image filtering and gradient domain guided image filtering of source images are first applied before the weight maps of each scale are obtained using a saliency detection technology and filtering means with three different fusion rules at different scales. The three types of fusion rules are for small-scale detail level, large-scale detail level, and base level. Finally, the target becomes more salient and can be more easily detected in the fusion result, with the detail information of the scene being fully displayed. After analyzing the experimental comparisons with state-of-the-art fusion methods, the HMSD-GDGF method has obvious advantages in fidelity of salient information (including structural similarity, brightness, and contrast), preservation of edge features, and human visual perception. Therefore, visual effects can be improved by using the proposed HMSD-GDGF method.

Detection of latent bloodstains beneath painted surfaces using reflected infrared photography.

PubMed

Farrar, Andrew; Porter, Glenn; Renshaw, Adrian

2012-09-01

Bloodstain evidence is a highly valued form of physical evidence commonly found at scenes involving violent crimes. However, painting over bloodstains will often conceal this type of evidence. There is limited research in the scientific literature that describes methods of detecting painted-over bloodstains. This project employed a modified digital single-lens reflex camera to investigate the effectiveness of infrared (IR) photography in detecting latent bloodstain evidence beneath a layer or multiple layers of paint. A qualitative evaluation was completed by comparing images taken of a series of samples using both IR and standard (visible light) photography. Further quantitative image analysis was used to verify the findings. Results from this project indicate that bloodstain evidence can be detected beneath up to six layers of paint using reflected IR; however, the results vary depending on the characteristics of the paint. This technique provides crime scene specialists with a new field method to assist in locating, visualizing, and documenting painted-over bloodstain evidence. © 2012 American Academy of Forensic Sciences.

Photonically enabled Ka-band radar and infrared sensor subscale testbed

NASA Astrophysics Data System (ADS)

Lohr, Michele B.; Sova, Raymond M.; Funk, Kevin B.; Airola, Marc B.; Dennis, Michael L.; Pavek, Richard E.; Hollenbeck, Jennifer S.; Garrison, Sean K.; Conard, Steven J.; Terry, David H.

2014-10-01

A subscale radio frequency (RF) and infrared (IR) testbed using novel RF-photonics techniques for generating radar waveforms is currently under development at The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to study target scenarios in a laboratory setting. The linearity of Maxwell's equations allows the use of millimeter wavelengths and scaled-down target models to emulate full-scale RF scene effects. Coupled with passive IR and visible sensors, target motions and heating, and a processing and algorithm development environment, this testbed provides a means to flexibly and cost-effectively generate and analyze multi-modal data for a variety of applications, including verification of digital model hypotheses, investigation of correlated phenomenology, and aiding system capabilities assessment. In this work, concept feasibility is demonstrated for simultaneous RF, IR, and visible sensor measurements of heated, precessing, conical targets and of a calibration cylinder. Initial proof-of-principle results are shown of the Ka-band subscale radar, which models S-band for 1/10th scale targets, using stretch processing and Xpatch models.

Image processing methods to compensate for IFOV errors in microgrid imaging polarimeters

NASA Astrophysics Data System (ADS)

Ratliff, Bradley M.; Boger, James K.; Fetrow, Matthew P.; Tyo, J. Scott; Black, Wiley T.

2006-05-01

Long-wave infrared imaging Stokes vector polarimeters are used in many remote sensing applications. Imaging polarimeters require that several measurements be made under optically different conditions in order to estimate the polarization signature at a given scene point. This multiple-measurement requirement introduces error in the signature estimates, and the errors differ depending upon the type of measurement scheme used. Here, we investigate a LWIR linear microgrid polarimeter. This type of instrument consists of a mosaic of micropolarizers at different orientations that are masked directly onto a focal plane array sensor. In this scheme, each polarization measurement is acquired spatially and hence each is made at a different point in the scene. This is a significant source of error, as it violates the requirement that each polarization measurement have the same instantaneous field-of-view (IFOV). In this paper, we first study the amount of error introduced by the IFOV handicap in microgrid instruments. We then proceed to investigate means for mitigating the effects of these errors to improve the quality of polarimetric imagery. In particular, we examine different interpolation schemes and gauge their performance. These studies are completed through the use of both real instrumental and modeled data.

High-Resolution View of Fires and Smoke near Sydney, Australia

NASA Technical Reports Server (NTRS)

2002-01-01

Smoke obscures much of the landscape near Sydney, Australia, in the true-color image above (top). However, the areas with active fires are revealed by the false-color image (bottom), which was made using shortwave infrared data that are sensitive to heat and provide the ability to 'see' through smoke. In the bottom scene, the black areas show fresh burn scars, while greens show landscape untouched by fire. Apparently, the fire burned up to the edge of a road (the thin black line snaking from the lefthand side of the image and disappearing off the bottom) and was unable to jump across. The thick dark line along the bottom of the scene is a river. Both images were made using data acquired on December 28, 2001, by the Advanced Land Imager (ALI), flying aboard NASA's Earth Observing-1 (EO-1) satellite. For more images of the recent fires in Australia, read Smoke Blankets New South Wales, Australia, Fires Continue to Rage Near Sydney, Australia, and Severe Bush Fires Near Sydney, Australia. For more information about the effects of fire on the environment, read the Biomass Burning fact sheet. Images by Robert Simmon, based on data provided by Lawrence Ong, EO-1 Science Team

Hyperspectral imaging applied to forensic medicine

NASA Astrophysics Data System (ADS)

Malkoff, Donald B.; Oliver, William R.

2000-03-01

Remote sensing techniques now include the use of hyperspectral infrared imaging sensors covering the mid-and- long wave regions of the spectrum. They have found use in military surveillance applications due to their capability for detection and classification of a large variety of both naturally occurring and man-made substances. The images they produce reveal the spatial distributions of spectral patterns that reflect differences in material temperature, texture, and composition. A program is proposed for demonstrating proof-of-concept in using a portable sensor of this type for crime scene investigations. It is anticipated to be useful in discovering and documenting the affects of trauma and/or naturally occurring illnesses, as well as detecting blood spills, tire patterns, toxic chemicals, skin injection sites, blunt traumas to the body, fluid accumulations, congenital biochemical defects, and a host of other conditions and diseases. This approach can significantly enhance capabilities for determining the circumstances of death. Potential users include law enforcement organizations (police, FBI, CIA), medical examiners, hospitals/emergency rooms, and medical laboratories. Many of the image analysis algorithms already in place for hyperspectral remote sensing and crime scene investigations can be applied to the interpretation of data obtained in this program.

Texture generation for use in synthetic infrared scenes

NASA Astrophysics Data System (ADS)

Ota, Clem Z.; Rollins, John M.; Bleiweiss, Max P.

1996-06-01

In the process of creating synthetic scenes for use in simulations/visualizations, texture is used as a surrogate to 'high' spatial definition. For example, if one were to measure the location of every blade of grass and all of the characteristics of each blade of grass in a lawn, then in the process of composing a scene of the lawn, it would be expected that the result would appear 'real;' however, because this process is excruciatingly laborious, various techniques have been devised to place the required details in the scene through the use of texturing. Experience gained during the recent Smart Weapons Operability Enhancement Joint Test and Evaluation (SWOE JT&E) has shown the need for higher fidelity texturing algorithms and a better parameterization of those that are in use. In this study, four aspects of the problem have been analyzed: texture extraction, texture insertion, texture metrics, and texture creation algorithms. The results of extracting real texture from an image, measuring it with a variety of metrics, and generating similar texture with three different algorithms is presented. These same metrics can be used to define clutter and to make comparisons between 'real' and synthetic (or artificial) scenes in an objective manner.

Reflectance of vegetation, soil, and water

NASA Technical Reports Server (NTRS)

Wiegand, C. L. (Principal Investigator)

1973-01-01

The author has identified the following significant results. The ability to read the 24-channel MSS CCT tapes, select specified agricultural land use areas from the CCT, and perform multivariate statistical and pattern recognition analyses has been demonstrated. The 5 optimum channels chosen for classifying an agricultural scene were, in the order of their selection the far red visible, short reflective IR, visible blue, thermal infrared, and ultraviolet portions of the electromagnetic spectrum, respectively. Although chosen by a training set containing only vegetal categories, the optimum 4 channels discriminated pavement, water, bare soil, and building roofs, as well as the vegetal categories. Among the vegetal categories, sugar cane and cotton had distinctive signatures that distinguished them from grass and citrus. Acreages estimated spectrally by the computer for the test scene were acceptably close to acreages estimated from aerial photographs for cotton, sugar cane, and water. Many nonfarmable land resolution elements representing drainage ditch, field road, and highway right-of-way as well as farm headquarters area fell into the grass, bare soil plus weeds, and citrus categories and lessened the accuracy of the farmable acreage estimates in these categories. The expertise developed using the 24-channel data will be applied to the ERTS-1 data.

Projector Center. What Is Biotechnology?

ERIC Educational Resources Information Center

Belzer, Bill; Case, Christine L.

1990-01-01

Presented is a menu designed to illustrate some classical examples of fermentation. This may be used to discuss biotechnology from a technological perspective. Other examples of biotechnology used in the foods industry are described. (CW)

Proper Use of Audio-Visual Aids: Essential for Educators.

ERIC Educational Resources Information Center

Dejardin, Conrad

1989-01-01

Criticizes educators as the worst users of audio-visual aids and among the worst public speakers. Offers guidelines for the proper use of an overhead projector and the development of transparencies. (DMM)

Enhanced backgrounds in scene rendering with GTSIMS

NASA Astrophysics Data System (ADS)

Prussing, Keith F.; Pierson, Oliver; Cordell, Chris; Stewart, John; Nielson, Kevin

2018-05-01

A core component to modeling visible and infrared sensor responses is the ability to faithfully recreate background noise and clutter in a synthetic image. Most tracking and detection algorithms use a combination of signal to noise or clutter to noise ratios to determine if a signature is of interest. A primary source of clutter is the background that defines the environment in which a target is placed. Over the past few years, the Electro-Optical Systems Laboratory (EOSL) at the Georgia Tech Research Institute has made significant improvements to its in house simulation framework GTSIMS. First, we have expanded our terrain models to include the effects of terrain orientation on emission and reflection. Second, we have included the ability to model dynamic reflections with full BRDF support. Third, we have added the ability to render physically accurate cirrus clouds. And finally, we have updated the overall rendering procedure to reduce the time necessary to generate a single frame by taking advantage of hardware acceleration. Here, we present the updates to GTSIMS to better predict clutter and noise doe to non-uniform backgrounds. Specifically, we show how the addition of clouds, terrain, and improved non-uniform sky rendering improve our ability to represent clutter during scene generation.

Discussion of band selection and methodologies for the estimation of precipitable water vapour from AVIRIS data

NASA Technical Reports Server (NTRS)

Schanzer, Dena; Staenz, Karl

1992-01-01

An Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data set acquired over Canal Flats, B.C., on 14 Aug. 1990, was used for the purpose of developing methodologies for surface reflectance retrieval using the 5S atmospheric code. A scene of Rogers Dry Lake, California (23 Jul. 1990), acquired within three weeks of the Canal Flats scene, was used as a potential reference for radiometric calibration purposes and for comparison with other studies using primarily LOWTRAN7. Previous attempts at surface reflectance retrieval indicated that reflectance values in the gaseous absorption bands had the poorest accuracy. Modifications to 5S to use 1 nm step size, in order to make fuller use of the 20 cm(sup -1) resolution of the gaseous absorption data, resulted in some improvement in the accuracy of the retrieved surface reflectance. Estimates of precipitable water vapor using non-linear least squares regression and simple ratioing techniques such as the CIBR (Continuum Interpolated Band Ratio) technique or the narrow/wide technique, which relate ratios of combinations of bands to precipitable water vapor through calibration curves, were found to vary widely. The estimates depended on the bands used for the estimation; none provided entirely satisfactory surface reflectance curves.

Physics meets fine arts: a project-based learning path on infrared imaging

NASA Astrophysics Data System (ADS)

Bonanno, A.; Bozzo, G.; Sapia, P.

2018-03-01

Infrared imaging represents a noninvasive tool for cultural heritage diagnostics, based on the capability of IR radiation to penetrate the most external layers of different objects (as for example paintings), revealing hidden features of artworks. From an educational viewpoint, this diagnostic technique offers teachers the opportunity to address manifold topics pertaining to the physics and technology of electromagnetic radiation, with particular emphasis on the nature of color and its physical correlates. Moreover, the topic provides interesting interdisciplinary bridges towards the human sciences. In this framework, we present a hands-on learning sequence, suitable for both high school students and university freshmen, inspired by the project-based learning (PBL) paradigm, designed and implemented in the context of an Italian national project aimed at offering students the opportunity to participate in educational activities within a real working context. In a preliminary test we involved a group of 23 high school students while they were working as apprentices in the Laboratory of Applied Physics for Cultural Heritage (ArcheoLab) at the University of Calabria. Consistently with the PBL paradigm, students were given well-defined practical goals to be achieved. As final goals they were asked (i) to construct and to test a low cost device (based on a disused commercial camera) appropriate for performing educational-grade IR investigations on paintings, and (ii) to prepare a device working as a simple spectrometer (recycling the optical components of a disused video projector), suitable for characterizing various light sources in order to identify the most appropriate for infrared imaging. The proposed learning path has shown (in the preliminary test) to be effective in fostering students’ interest towards physics and its technological applications, especially because pupils perceived the context (i.e. physics applied to the protection and restoration of cultural heritage) as relevant in relation to the cultural and productive specificities of their country. The learning sequence, originally designed for high school students in apprenticeship at the university, can be easily improved to make it appropriate for university freshmen.

More Fun with Singing Wineglasses.

ERIC Educational Resources Information Center

Planinsic, Gorazd

2000-01-01

Describes a method for visually demonstrating resonance in a wine glass on an overhead projector. Provides instructions for making a "howling" wine glass where two slightly different tones separated by an irritating interval sound alternately. (WRM)

Adaptation of the projector-augmented-wave formalism to the treatment of orbital-dependent exchange-correlation functionals

NASA Astrophysics Data System (ADS)

Xu, Xiao; Holzwarth, N. A. W.

2011-10-01

This paper presents the formulation and numerical implementation of a self-consistent treatment of orbital-dependent exchange-correlation functionals within the projector-augmented-wave method of Blöchl [Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.50.17953 50, 17953 (1994)] for electronic structure calculations. The methodology is illustrated with binding energy curves for C in the diamond structure and LiF in the rock salt structure, by comparing results from the Hartree-Fock (HF) formalism and the optimized effective potential formalism in the so-called KLI approximation [Krieger, Li, and Iafrate, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.45.101 45, 101 (1992)] with those of the local density approximation. While the work here uses pure Fock exchange only, the formalism can be extended to treat orbital-dependent functionals more generally.

Crime scene investigation, reporting, and reconstuction (CSIRR)

NASA Astrophysics Data System (ADS)

Booth, John F.; Young, Jeffrey M.; Corrigan, Paul

1997-02-01

Graphic Data Systems Corporation (GDS Corp.) and Intellignet Graphics Solutions, Inc. (IGS) combined talents in 1995 to design and develop a MicroGDSTM application to support field investiations of crime scenes, such as homoicides, bombings, and arsons. IGS and GDS Corp. prepared design documents under the guidance of federal, state, and local crime scene reconstruction experts and with information from the FBI's evidence response team field book. The application was then developed to encompass the key components of crime scene investigaton: staff assigned to the incident, tasks occuring at the scene, visits to the scene location, photogrpahs taken of the crime scene, related documents, involved persons, catalogued evidence, and two- or three- dimensional crime scene reconstruction. Crime scene investigation, reporting, and reconstruction (CSIRR$CPY) provides investigators with a single applicaiton for both capturing all tabular data about the crime scene and quickly renderng a sketch of the scene. Tabular data is captured through ituitive database forms, while MicroGDSTM has been modified to readily allow non-CAD users to sketch the scene.

Scene recognition following locomotion around a scene.

PubMed

Motes, Michael A; Finlay, Cory A; Kozhevnikov, Maria

2006-01-01

Effects of locomotion on scene-recognition reaction time (RT) and accuracy were studied. In experiment 1, observers memorized an 11-object scene and made scene-recognition judgments on subsequently presented scenes from the encoded view or different views (ie scenes were rotated or observers moved around the scene, both from 40 degrees to 360 degrees). In experiment 2, observers viewed different 5-object scenes on each trial and made scene-recognition judgments from the encoded view or after moving around the scene, from 36 degrees to 180 degrees. Across experiments, scene-recognition RT increased (in experiment 2 accuracy decreased) with angular distance between encoded and judged views, regardless of how the viewpoint changes occurred. The findings raise questions about conditions in which locomotion produces spatially updated representations of scenes.

Biology Notes.

ERIC Educational Resources Information Center

School Science Review, 1980

1980-01-01

Describes equipment, activities, and experiments useful in biology and environmental education instruction, including, among others, sampling in ecology using an overhead projector, the slide finder as an aid to microscopy, teaching kidney function, and teaching wildlife conservation-sand dune systems. (SK)

WEBSLIDE: A "Virtual" Slide Projector Based on World Wide Web.

ERIC Educational Resources Information Center

Barra, Maria; Ferrandino, Salvatore; Scarano, Vittorio

1999-01-01

Presents the key design concepts of a software project whose objective is to provide a simple, cheap, and efficient solution for showing slides during lessons in computer labs. Contains 26 references. (DDR)

Density functional theory calculations of 95Mo NMR parameters in solid-state compounds.

PubMed

Cuny, Jérôme; Furet, Eric; Gautier, Régis; Le Pollès, Laurent; Pickard, Chris J; d'Espinose de Lacaillerie, Jean-Baptiste

2009-12-21

The application of periodic density functional theory-based methods to the calculation of (95)Mo electric field gradient (EFG) and chemical shift (CS) tensors in solid-state molybdenum compounds is presented. Calculations of EFG tensors are performed using the projector augmented-wave (PAW) method. Comparison of the results with those obtained using the augmented plane wave + local orbitals (APW+lo) method and with available experimental values shows the reliability of the approach for (95)Mo EFG tensor calculation. CS tensors are calculated using the recently developed gauge-including projector augmented-wave (GIPAW) method. This work is the first application of the GIPAW method to a 4d transition-metal nucleus. The effects of ultra-soft pseudo-potential parameters, exchange-correlation functionals and structural parameters are precisely examined. Comparison with experimental results allows the validation of this computational formalism.

Impact of various lecture delivery methods in pharmacology

PubMed Central

Seth, Vikas; Upadhyaya, Prerna; Ahmad, Mushtaq; Kumar, Virendra

2010-01-01

The aim of the study was to assess the impact of three common lecture delivery methods viz. the lectures using chalkboard, the lectures using PowerPoint presentations and the lectures utilizing transparencies with an overhead projector. By filling in a questionnaire, the second year MBBS students were asked to assess the impact of three pharmacology lectures given by three different methods of lecture delivery. Also after each lecture an objective test was given to compare the impact of the lecture delivered by different methods. The results of the study show that as per the subjective assessment of the lectures, students preferred PowerPoint teaching the most. As far as the students' performance is concerned the impact of traditional Chalkboard and PowerPoint teaching was much more than the lectures using transparency and overhead projector (OHP). PMID:29255392

Towards Robust Self-Calibration for Handheld 3d Line Laser Scanning

NASA Astrophysics Data System (ADS)

Bleier, M.; Nüchter, A.

2017-11-01

This paper studies self-calibration of a structured light system, which reconstructs 3D information using video from a static consumer camera and a handheld cross line laser projector. Intersections between the individual laser curves and geometric constraints on the relative position of the laser planes are exploited to achieve dense 3D reconstruction. This is possible without any prior knowledge of the movement of the projector. However, inaccurrately extracted laser lines introduce noise in the detected intersection positions and therefore distort the reconstruction result. Furthermore, when scanning objects with specular reflections, such as glossy painted or metalic surfaces, the reflections are often extracted from the camera image as erroneous laser curves. In this paper we investiagte how robust estimates of the parameters of the laser planes can be obtained despite of noisy detections.

Does scene context always facilitate retrieval of visual object representations?

PubMed

Nakashima, Ryoichi; Yokosawa, Kazuhiko

2011-04-01

An object-to-scene binding hypothesis maintains that visual object representations are stored as part of a larger scene representation or scene context, and that scene context facilitates retrieval of object representations (see, e.g., Hollingworth, Journal of Experimental Psychology: Learning, Memory and Cognition, 32, 58-69, 2006). Support for this hypothesis comes from data using an intentional memory task. In the present study, we examined whether scene context always facilitates retrieval of visual object representations. In two experiments, we investigated whether the scene context facilitates retrieval of object representations, using a new paradigm in which a memory task is appended to a repeated-flicker change detection task. Results indicated that in normal scene viewing, in which many simultaneous objects appear, scene context facilitation of the retrieval of object representations-henceforth termed object-to-scene binding-occurred only when the observer was required to retain much information for a task (i.e., an intentional memory task).

Integral freeform illumination lens design of LED based pico-projector.

PubMed

Zhao, Shuang; Wang, Kai; Chen, Fei; Qin, Zong; Liu, Sheng

2013-05-01

In this paper, an illumination lens design for a LED-based pico-projector is presented. Different from the traditional illumination systems composed by lens group, the integral illumination lens consists of a total internal reflector (TIR) and a freeform surface. TIR acts as collimation lens and its top surface formed by a freeform surface reshapes the nonuniform circular light pattern generated by TIR to be rectangular and uniform. Diameter and height of the lens are 16 and 10 mm, respectively. An optimization method to deal with the problem of extended light source is also presented in detail in this paper. According to the simulation results of the final optimized lens, 77% (neglecting the effect of polarization) of the power of light source is collected on liquid crystal on silicon panel with a 16∶9 ratio and illumination uniformity achieves 92%.

Structured light system calibration method with optimal fringe angle.

PubMed

Li, Beiwen; Zhang, Song

2014-11-20

For structured light system calibration, one popular approach is to treat the projector as an inverse camera. This is usually performed by projecting horizontal and vertical sequences of patterns to establish one-to-one mapping between camera points and projector points. However, for a well-designed system, either horizontal or vertical fringe images are not sensitive to depth variation and thus yield inaccurate mapping. As a result, the calibration accuracy is jeopardized if a conventional calibration method is used. To address this limitation, this paper proposes a novel calibration method based on optimal fringe angle determination. Experiments demonstrate that our calibration approach can increase the measurement accuracy up to 38% compared to the conventional calibration method with a calibration volume of 300(H)  mm×250(W)  mm×500(D)  mm.

Synesthetic colors induced by graphemes that have not been consciously perceived.

PubMed

Ramachandran, V S; Seckel, Elizabeth

2015-01-01

Grapheme-color synesthetes experience colors when they see printed letters of the alphabet. Currently, we tested four "projector" synesthetes, whose colors evoked by graphemes have sensory support or quale and appear to be restricted spatially to the letters like real colors. We use three different kinds of puzzle pictures that contained hidden letters, which require 30 s or more for nonsynesthetes to identify. Grapheme-color projector synesthetes recognize them three times faster and report that the colors were evoked before conscious letter recognition, clueing them as to what the letters were. Subjectively, the synesthetic subjects reported that they also saw mirror-reversed letters in the same colors as nonreversed letters which enabled them to read mirror-reversed text at thrice the normal speed. We conclude that in some synesthetes colors are evoked preconsciously early in sensory processing.

Full-color stereoscopic single-pixel camera based on DMD technology

NASA Astrophysics Data System (ADS)

Salvador-Balaguer, Eva; Clemente, Pere; Tajahuerce, Enrique; Pla, Filiberto; Lancis, Jesús

2017-02-01

Imaging systems based on microstructured illumination and single-pixel detection offer several advantages over conventional imaging techniques. They are an effective method for imaging through scattering media even in the dynamic case. They work efficiently under low light levels, and the simplicity of the detector makes it easy to design imaging systems working out of the visible spectrum and to acquire multidimensional information. In particular, several approaches have been proposed to record 3D information. The technique is based on sampling the object with a sequence of microstructured light patterns codified onto a programmable spatial light modulator while light intensity is measured with a single-pixel detector. The image is retrieved computationally from the photocurrent fluctuations provided by the detector. In this contribution we describe an optical system able to produce full-color stereoscopic images by using few and simple optoelectronic components. In our setup we use an off-the-shelf digital light projector (DLP) based on a digital micromirror device (DMD) to generate the light patterns. To capture the color of the scene we take advantage of the codification procedure used by the DLP for color video projection. To record stereoscopic views we use a 90° beam splitter and two mirrors, allowing us two project the patterns form two different viewpoints. By using a single monochromatic photodiode we obtain a pair of color images that can be used as input in a 3-D display. To reduce the time we need to project the patterns we use a compressive sampling algorithm. Experimental results are shown.

General solution for high dynamic range three-dimensional shape measurement using the fringe projection technique

NASA Astrophysics Data System (ADS)

Feng, Shijie; Zhang, Yuzhen; Chen, Qian; Zuo, Chao; Li, Rubin; Shen, Guochen

2014-08-01

This paper presents a general solution for realizing high dynamic range three-dimensional (3-D) shape measurement based on fringe projection. Three concrete techniques are involved in the solution for measuring object with large range of reflectivity (LRR) or one with shiny specular surface. For the first technique, the measured surface reflectivities are sub-divided into several groups based on its histogram distribution, then the optimal exposure time for each group can be predicted adaptively so that the bright as well as dark areas on the measured surface are able to be handled without any compromise. Phase-shifted images are then captured at the calculated exposure times and a composite phase-shifted image is generated by extracting the optimally exposed pixels in the raw fringes images. For the second technique, it is proposed by introducing two orthogonal polarizers which are placed separately in front of the camera and projector into the first technique and the third one is developed by combining the second technique with the strategy of properly altering the angle between the transmission axes of the two polarizers. Experimental results show that the first technique can effectively improve the measurement accuracy of diffuse objects with LRR, the second one is capable of measuring object with weak specular reflection (WSR: e.g. shiny plastic surface) and the third can inspect surface with strong specular reflection (SSR: e.g. highlight on aluminum alloy) precisely. Further, more complex scene, such as the one with LRR and WSR, or even the one simultaneously involving LRR, WSR and SSR, can be measured accurately by the proposed solution.

An improved non-uniformity correction algorithm and its hardware implementation on FPGA

NASA Astrophysics Data System (ADS)

Rong, Shenghui; Zhou, Huixin; Wen, Zhigang; Qin, Hanlin; Qian, Kun; Cheng, Kuanhong

2017-09-01

The Non-uniformity of Infrared Focal Plane Arrays (IRFPA) severely degrades the infrared image quality. An effective non-uniformity correction (NUC) algorithm is necessary for an IRFPA imaging and application system. However traditional scene-based NUC algorithm suffers the image blurring and artificial ghosting. In addition, few effective hardware platforms have been proposed to implement corresponding NUC algorithms. Thus, this paper proposed an improved neural-network based NUC algorithm by the guided image filter and the projection-based motion detection algorithm. First, the guided image filter is utilized to achieve the accurate desired image to decrease the artificial ghosting. Then a projection-based moving detection algorithm is utilized to determine whether the correction coefficients should be updated or not. In this way the problem of image blurring can be overcome. At last, an FPGA-based hardware design is introduced to realize the proposed NUC algorithm. A real and a simulated infrared image sequences are utilized to verify the performance of the proposed algorithm. Experimental results indicated that the proposed NUC algorithm can effectively eliminate the fix pattern noise with less image blurring and artificial ghosting. The proposed hardware design takes less logic elements in FPGA and spends less clock cycles to process one frame of image.

Microfilming for Drafting Students

ERIC Educational Resources Information Center

Bass, Ronald E.

1972-01-01

If you have a 35mm camera, an enlarger or filmstrip projector, and developing equipment you can introduce your drafting students to one of the processes used in the newly emerging field of technical communication.'' (Editor)

Electromagnetic modelling of a space-borne far-infrared interferometer

NASA Astrophysics Data System (ADS)

Donohoe, Anthony; O'Sullivan, Créidhe; Murphy, J. Anthony; Bracken, Colm; Savini, Giorgio; Pascale, Enzo; Ade, Peter; Sudiwala, Rashmi; Hornsby, Amber

2016-02-01

In this paper I will describe work done as part of an EU-funded project `Far-infrared space interferometer critical assessment' (FISICA). The aim of the project is to investigate science objectives and technology development required for the next generation THz space interferometer. The THz/FIR is precisely the spectral region where most of the energy from stars, exo-planetary systems and galaxy clusters deep in space is emitted. The atmosphere is almost completely opaque in the wave-band of interest so any observation that requires high quality data must be performed with a space-born instrument. A space-borne far infrared interferometer will be able to answer a variety of crucial astrophysical questions such as how do planets and stars form, what is the energy engine of most galaxies and how common are the molecule building blocks of life. The FISICA team have proposed a novel instrument based on a double Fourier interferometer that is designed to resolve the light from an extended scene, spectrally and spatially. A laboratory prototype spectral-spatial interferometer has been constructed to demonstrate the feasibility of the double-Fourier technique at far infrared wavelengths (0.15 - 1 THz). This demonstrator is being used to investigate and validate important design features and data-processing methods for future instruments. Using electromagnetic modelling techniques several issues related to its operation at long baselines and wavelengths, such as diffraction, have been investigated. These are critical to the design of the concept instrument and the laboratory testbed.

Background Registration-Based Adaptive Noise Filtering of LWIR/MWIR Imaging Sensors for UAV Applications.

PubMed

Kim, Byeong Hak; Kim, Min Young; Chae, You Seong

2017-12-27

Unmanned aerial vehicles (UAVs) are equipped with optical systems including an infrared (IR) camera such as electro-optical IR (EO/IR), target acquisition and designation sights (TADS), or forward looking IR (FLIR). However, images obtained from IR cameras are subject to noise such as dead pixels, lines, and fixed pattern noise. Nonuniformity correction (NUC) is a widely employed method to reduce noise in IR images, but it has limitations in removing noise that occurs during operation. Methods have been proposed to overcome the limitations of the NUC method, such as two-point correction (TPC) and scene-based NUC (SBNUC). However, these methods still suffer from unfixed pattern noise. In this paper, a background registration-based adaptive noise filtering (BRANF) method is proposed to overcome the limitations of conventional methods. The proposed BRANF method utilizes background registration processing and robust principle component analysis (RPCA). In addition, image quality verification methods are proposed that can measure the noise filtering performance quantitatively without ground truth images. Experiments were performed for performance verification with middle wave infrared (MWIR) and long wave infrared (LWIR) images obtained from practical military optical systems. As a result, it is found that the image quality improvement rate of BRANF is 30% higher than that of conventional NUC.

Background Registration-Based Adaptive Noise Filtering of LWIR/MWIR Imaging Sensors for UAV Applications

PubMed Central

Kim, Byeong Hak; Kim, Min Young; Chae, You Seong

2017-01-01

Unmanned aerial vehicles (UAVs) are equipped with optical systems including an infrared (IR) camera such as electro-optical IR (EO/IR), target acquisition and designation sights (TADS), or forward looking IR (FLIR). However, images obtained from IR cameras are subject to noise such as dead pixels, lines, and fixed pattern noise. Nonuniformity correction (NUC) is a widely employed method to reduce noise in IR images, but it has limitations in removing noise that occurs during operation. Methods have been proposed to overcome the limitations of the NUC method, such as two-point correction (TPC) and scene-based NUC (SBNUC). However, these methods still suffer from unfixed pattern noise. In this paper, a background registration-based adaptive noise filtering (BRANF) method is proposed to overcome the limitations of conventional methods. The proposed BRANF method utilizes background registration processing and robust principle component analysis (RPCA). In addition, image quality verification methods are proposed that can measure the noise filtering performance quantitatively without ground truth images. Experiments were performed for performance verification with middle wave infrared (MWIR) and long wave infrared (LWIR) images obtained from practical military optical systems. As a result, it is found that the image quality improvement rate of BRANF is 30% higher than that of conventional NUC. PMID:29280970

Neuromorphic infrared focal plane performs sensor fusion on-plane local-contrast-enhancement spatial and temporal filtering

NASA Astrophysics Data System (ADS)

Massie, Mark A.; Woolaway, James T., II; Curzan, Jon P.; McCarley, Paul L.

1993-08-01

An infrared focal plane has been simulated, designed and fabricated which mimics the form and function of the vertebrate retina. The `Neuromorphic' focal plane has the capability of performing pixel-based sensor fusion and real-time local contrast enhancement, much like the response of the human eye. The device makes use of an indium antimonide detector array with a 3 - 5 micrometers spectral response, and a switched capacitor resistive network to compute a real-time 2D spatial average. This device permits the summation of other sensor outputs to be combined on-chip with the infrared detections of the focal plane itself. The resulting real-time analog processed information thus represents the combined information of many sensors with the advantage that analog spatial and temporal signal processing is performed at the focal plane. A Gaussian subtraction method is used to produce the pixel output which when displayed produces an image with enhanced edges, representing spatial and temporal derivatives in the scene. The spatial and temporal responses of the device are tunable during operation, permitting the operator to `peak up' the response of the array to spatial and temporally varying signals. Such an array adapts to ambient illumination conditions without loss of detection performance. This paper reviews the Neuromorphic infrared focal plane from initial operational simulations to detailed design characteristics, and concludes with a presentation of preliminary operational data for the device as well as videotaped imagery.

A Simple Water Channel

ERIC Educational Resources Information Center

White, A. S.

1976-01-01

Describes a simple water channel, for use with an overhead projector. It is run from a water tap and may be used for flow visualization experiments, including the effect of streamlining and elementary building aerodynamics. (MLH)

CERES Single Scanner Satellite Footprint, TOA, Surface Fluxes and Clouds (SSF) data in HDF (CER_SSF_Terra-FM1-MODIS_Edition2A)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Single Scanner Satellite Footprint, TOA, Surface Fluxes and Clouds (SSF) data in HDF (CER_SSF_Aqua-FM4-MODIS_Edition1B)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-03-29] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Single Satellite Footprint, TOA and Surface Fluxes, Clouds (SSF) data in HDF (CER_SSF_Aqua-FM4-MODIS_Edition2A)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-09-16] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

The Bionic Amoeba.

ERIC Educational Resources Information Center

Wright, Emmett L.

1979-01-01

A demonstration is described that encourages students to engage in inquiry in biology. Using chemicals and an overhead projector, the instructor can simulate a living organism projected onto a screen. The reaction can aid students in defining the characteristics of life. (SA)

A New Idea for Dissecting Tray

ERIC Educational Resources Information Center

Branham, Arthur

1976-01-01

A method of preparing a special dissecting tray to be used with transmitted light as well as reflected light is presented. It may also be used with an overhead projector to illustrate some skeletal structures in vertebrates. (Author/EB)

Low-Altitude AVIRIS Data for Mapping Land Cover in Yellowstone National Park: Use of Isodata Clustering Techniques

NASA Technical Reports Server (NTRS)

Spruce, Joseph P.

2001-01-01

Northeast Yellowstone National Park (YNP) has a diversity of forest, range, and wetland cover types. Several remote sensing studies have recently been done in this area, including the NASA Earth Observations Commercial Applications Program (EOCAP) hyperspectral project conducted by Yellowstone Ecosystems Studies (YES) on the use of hyperspectral imaging for assessing riparian and in-stream habitats. In 1999, YES and NASA's Commercial Remote Sensing Program Office began collaborative study of this area, assessing the potential of synergistic use of hyperspectral, synthetic aperture radar (SAR), and multiband thermal data for mapping forest, range, and wetland land cover. Since the beginning, a quality 'reference' land cover map has been desired as a tool for developing and validating other land cover maps produced during the project. This paper recounts an effort to produce such a reference land cover map using low-altitude Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and unsupervised classification techniques. The main objective of this study is to assess ISODATA classification for mapping land cover in Northeast YNP using select bands of low-altitude AVIRIS data. A secondary, more long-term objective is to assess the potential for improving ISODATA-based classification of land cover through use of principal components analysis and minimum noise fraction (MNF) techniques. This paper will primarily report on work regarding the primary research objective. This study focuses on an AVIRIS cube acquired on July 23, 1999, by the confluence of Soda Butte Creek with the Lamar River. Range and wetland habitats dominate the image with forested habitats being a comparatively minor component of the scene. The scene generally tracks from southwest to northeast. Most of the scene is valley bottom with some lower side slopes occurring on the western portion. Elevations within the AVIRIS scene range from approximately 1998 to 2165 m above sea level, based on US Geological Survey (USGS) 30-m digital elevation model (DEM) data. Despain and the National Park Service (NPS) provide additional description of the study area.

CERES Single Scanner Satellite Footprint, TOA, Surface Fluxes and Clouds (SSF) data in HDF (CER_SSF_TRMM-PFM-VIRS_Edition1)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2000-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

The EarthCARE satellite payload

NASA Astrophysics Data System (ADS)

Wallace, Kotska; Perez-Albinana, Abelardo; Lemanczyk, Jerzy; Heliere, Arnaud; Wehr, Tobias; Eisinger, Michael; Lefebvre, Alain; Nakatsuka, Hirotaka; Tomita, Eiichi

2014-10-01

EarthCARE is ESA's third Earth Explorer Core Mission, with JAXA providing one instrument. The mission facilitates unique data product synergies, to improve understanding of atmospheric cloud-aerosol interactions and Earth radiative balance, towards enhancing climate and numerical weather prediction models. This paper will describe the payload, consisting of two active instruments: an ATmospheric LIDar (ATLID) and a Cloud Profiling Radar (CPR), and two passive instruments: a Multi Spectral Imager (MSI) and a Broad Band Radiometer (BBR). ATLID is a UV lidar providing atmospheric echoes, with a vertical resolution of 100 m, up to 40 km altitude. Using very high spectral resolution filtering the relative contributions of particle (aerosols) and Rayleigh (molecular) back scattering will be resolved, allowing cloud and aerosol optical depth to be deduced. Particle scatter co- and cross-polarisation measurements will provide information about the cloud and aerosol particles' physical characteristics. JAXA's 94.05 GHz Cloud Profiling Radar operates with a pulse width of 3.3 μm and repetition frequency 6100 to 7500 Hz. The 2.5 m aperture radar will retrieve data on clouds and precipitation. Doppler shift measurements in the backscatter signal will furthermore allow inference of the vertical motion of particles to an accuracy of about 1 m/s. MSI's 500 m pixel data will provide cloud and aerosol information and give context to the active instrument measurements for 3-D scene construction. Four solar channels and three thermal infrared channels cover 35 km on one side to 115 km on the other side of the other instrument's observations. BBR measures reflected solar and emitted thermal radiation from the scene. To reduce uncertainty in the radiance to flux conversion, three independent view angles are observed for each scene. The combined data allows more accurate flux calculations, which can be further improved using MSI data.

CERES Single Scanner Satellite Footprint, TOA, Surface Fluxes and Clouds (SSF) data in HDF (CER_SSF_Terra-FM2-MODIS_Edition2B)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2006-01-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Single Scanner Satellite Footprint, TOA, Surface Fluxes and Clouds (SSF)- Test data in HDF (CER_SSF_TRMM-PFM-VIRS_Subset-Edition1)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=1998-08-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Single Scanner Satellite Footprint, TOA, Surface Fluxes and Clouds (SSF) data in HDF (CER_SSF_Terra-FM2-MODIS_Edition2A)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Single Satellite Footprint, TOA and Surface Fluxes, Clouds (SSF) data in HDF (CER_SSF_Aqua-FM4-MODIS_Ed2A-NoSW)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from a higher-resolution imager such as Visible/Infrared Scanner (VIRS) on TRMM or Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. For each CERES footprint, the SSF contains the number of cloud layers and for each layer the cloud amount, height, temperature, pressure, optical depth, emissivity, ice and liquid water path, and water particle size. The SSF also contains the CERES filtered radiances for the total, shortwave (SW), and window (WN) channels and the unfiltered SW, longwave (LW), and WN radiances. The SW, LW, and WN radiances at spacecraft altitude are converted to Top-of-the-Atmosphere (TOA) fluxes based on the imager defined scene. These TOA fluxes are used to estimate surface fluxes. Only footprints with adequate imager coverage are included on CER_SSF_TRMM-PFM-VIRS_Subset_Edition1the SSF which is much less than the full set of footprints on the CERES ES-8 product. The following CERES SSF data sets are currently available: CER_SSF_TRMM-PFM-VIRS_Edition1 CER_SSF_TRMM-PFM-VIRS_Subset_Edition1 CER_SSF_TRMM-PFM-VIRS_Edition2A CER_SSF_TRMM-SIM-VIRS_Edition2_VIRSonly CER_SSF_TRMM-PFM-VIRS_Edition2A-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B-TransOps CER_SSF_TRMM-PFM-VIRS_Edition2B CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition1A CER_SSF_Terra-FM1-MODIS_Edition2A CER_SSF_Terra-FM2-MODIS_Edition2A CER_SSF_Terra-FM1-MODIS_Edition2B CER_SSF_Terra-FM2-MODIS_Edition2B CER_SSF_Aqua-FM4-MODIS_Beta1 CER_SSF_Aqua-FM3-MODIS_Beta2 CER_SSF_Aqua-FM4-MODIS_Beta2. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2006-01-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

Daylight operation of a sodium laser guide star

NASA Astrophysics Data System (ADS)

Hart, Michael; Jefferies, Stuart; Murphy, Neil

2016-07-01

We report photometric measurements of a sodium resonance guide star against the daylight sky when observed through a tuned magneto-optical filter (MOF). The MOF comprises a sodium vapor cell in a kilogauss-level magnetic field between crossed polarizers and has a very narrow transmission profile at the sodium D2 resonance of approximately 0.008 nm. Our observations were made with the 1.5 m Kuiper telescope on Mt. Bigelow, AZ, which has a separately mounted guide star laser projecting a circularly polarized single-frequency beam of approximately 6.5 W at 589.16 nm. Both the beam projector and the 1.5 m telescope were pointed close to zenith; the baseline between them is approximately 5 m. Measurements of the guide star were made on the morning of 2016 March 24 using an imaging camera focused on the beacon and looking through the full aperture of the telescope. The guide star flux was estimated at 1.20×106 photon/m2/s while at approximately 45 minutes after sunrise, the sky background through the MOF was 1100 photon/m2/s/arcsec2. We interpret our results in terms of thermal infrared observations with adaptive optics on the next generation of extremely large telescopes now being built.

The Blue Bottle Experiment--Simple Demonstration of Self-Organization.

ERIC Educational Resources Information Center

Adamcikova, L'ubica; Sevcik, Peter

1998-01-01

Explains a way of observing pattern formation in the Blue Bottle chemistry demonstration by pouring a solution containing sodium hydroxide, glucose, and dye into a Petri dish and placing the dish on an overhead projector. (WRM)

Digital Simulation Of Precise Sensor Degradations Including Non-Linearities And Shift Variance

NASA Astrophysics Data System (ADS)

Kornfeld, Gertrude H.

1987-09-01

Realistic atmospheric and Forward Looking Infrared Radiometer (FLIR) degradations were digitally simulated. Inputs to the routine are environmental observables and the FLIR specifications. It was possible to achieve realism in the thermal domain within acceptable computer time and random access memory (RAM) requirements because a shift variant recursive convolution algorithm that well describes thermal properties was invented and because each picture element (pixel) has radiative temperature, a materials parameter and range and altitude information. The computer generation steps start with the image synthesis of an undegraded scene. Atmospheric and sensor degradation follow. The final result is a realistic representation of an image seen on the display of a specific FLIR.

ERBE Geographic Scene and Monthly Snow Data

NASA Technical Reports Server (NTRS)

Coleman, Lisa H.; Flug, Beth T.; Gupta, Shalini; Kizer, Edward A.; Robbins, John L.

1997-01-01

The Earth Radiation Budget Experiment (ERBE) is a multisatellite system designed to measure the Earth's radiation budget. The ERBE data processing system consists of several software packages or sub-systems, each designed to perform a particular task. The primary task of the Inversion Subsystem is to reduce satellite altitude radiances to fluxes at the top of the Earth's atmosphere. To accomplish this, angular distribution models (ADM's) are required. These ADM's are a function of viewing and solar geometry and of the scene type as determined by the ERBE scene identification algorithm which is a part of the Inversion Subsystem. The Inversion Subsystem utilizes 12 scene types which are determined by the ERBE scene identification algorithm. The scene type is found by combining the most probable cloud cover, which is determined statistically by the scene identification algorithm, with the underlying geographic scene type. This Contractor Report describes how the geographic scene type is determined on a monthly basis.

Liquid crystal true 3D displays for augmented reality applications

NASA Astrophysics Data System (ADS)

Li, Yan; Liu, Shuxin; Zhou, Pengcheng; Chen, Quanming; Su, Yikai

2018-02-01

Augmented reality (AR) technology, which integrates virtual computer-generated information into the real world scene, is believed to be the next-generation human-machine interface. However, most AR products adopt stereoscopic 3D display technique, which causes the accommodation-vergence conflict. To solve this problem, we have proposed two approaches. The first is a multi-planar volumetric display using fast switching polymer-stabilized liquid crystal (PSLC) films. By rapidly switching the films between scattering and transparent states while synchronizing with a high-speed projector, the 2D slices of a 3D volume could be displayed in time sequence. We delved into the research on developing high-performance PSLC films in both normal mode and reverse mode; moreover, we also realized the demonstration of four-depth AR images with correct accommodation cues. For the second approach, we realized a holographic AR display using digital blazed gratings and a 4f system to eliminate zero-order and higher-order noise. With a 4k liquid crystal on silicon device, we achieved a field of view (FOV) of 32 deg. Moreover, we designed a compact waveguidebased holographic 3D display. In the design, there are two holographic optical elements (HOEs), each of which functions as a diffractive grating and a Fresnel lens. Because of the grating effect, holographic 3D image light is coupled into and decoupled out of the waveguide by modifying incident angles. Because of the lens effect, the collimated zero order light is focused at a point, and got filtered out. The optical power of the second HOE also helps enlarge FOV.

Infrared negative luminescent devices and higher operating temperature detectors

NASA Astrophysics Data System (ADS)

Nash, G. R.; Gordon, N. T.; Hall, D. J.; Ashby, M. K.; Little, J. C.; Masterton, G.; Hails, J. E.; Giess, J.; Haworth, L.; Emeny, M. T.; Ashley, T.

2004-01-01

Infrared LEDs and negative luminescent devices, where less light is emitted than in equilibrium, have been attracting an increasing amount of interest recently. They have a variety of applications, including as a ‘source’ of IR radiation for gas sensing; radiation shielding for, and non-uniformity correction of, high sensitivity staring infrared detectors; and dynamic infrared scene projection. Similarly, infrared (IR) detectors are used in arrays for thermal imaging and, discretely, in applications such as gas sensing. Multi-layer heterostructure epitaxy enables the growth of both types of device using designs in which the electronic processes can be precisely controlled and techniques such as carrier exclusion and extraction can be implemented. This enables detectors to be made which offer good performance at higher than normal operating temperatures, and efficient negative luminescent devices to be made which simulate a range of effective temperatures whilst operating uncooled. In both cases, however, additional performance benefits can be achieved by integrating optical concentrators around the diodes to reduce the volume of semiconductor material, and so minimise the thermally activated generation-recombination processes which compete with radiative mechanisms. The integrated concentrators are in the form of Winston cones, which can be formed using an iterative dry etch process involving methane/hydrogen and oxygen. We present results on negative luminescence in the mid- and long-IR wavebands, from devices made from indium antimonide and mercury cadmium telluride, where the aim is sizes greater than 1 cm×1 cm. We also discuss progress on, and the potential for, operating temperature and/or sensitivity improvement of detectors, where very high-performance imaging is anticipated from systems which require no mechanical cooling.

Determination of NMR chemical shifts for cholesterol crystals from first-principles

NASA Astrophysics Data System (ADS)

Kucukbenli, Emine; de Gironcoli, Stefano

2011-03-01

Solid State Nuclear Magnetic Resonance (NMR) is a powerful tool in crystallography when combined with theoretical predictions. So far, empirical calculations of spectra have been employed for an unambiguous identification. However, many complex systems are outside the scope of these methods. Our implementation of ultrasoft and projector augmented wave pseudopotentials within ab initio gauge including projector augmented plane wave (GIPAW) method in Quantum Espresso simulation package allows affordable calculations of NMR spectra for systems of thousands of electrons. We report here the first ab initio determination of NMR spectra for several crystal structures of cholesterol. Cholesterol crystals, the main component of human gallstones, are of interest to medical research as their structural properties can shed light on the pathologies of gallbladder. With our application we show that ab initio calculations can be employed to aid NMR crystallography.

BRST technique for the cosmological density matrix

NASA Astrophysics Data System (ADS)

Barvinsky, A. O.

2013-10-01

The microcanonical density matrix in closed cosmology has a natural definition as a projector on the space of solutions of Wheeler-DeWitt equations, which is motivated by the absence of global non-vanishing charges and energy in spatially closed gravitational systems. Using the BRST/BFV formalism in relativistic phase space of gauge and ghost variables we derive the path integral representation for this projector and the relevant statistical sum. This derivation circumvents the difficulties associated with the open algebra of noncommutative quantum Dirac constraints and the construction/regularization of the physical inner product in the subspace of BRS singlets. This inner product is achieved via the Batalin-Marnelius gauge fixing in the space of BRS-invariant states, which in its turn is shown to be a result of truncation of the BRST/BFV formalism to the "matter" sector of relativistic phase space.

Hyper thin 3D edge measurement of honeycomb core structures based on the triangular camera-projector layout & phase-based stereo matching.

PubMed

Jiang, Hongzhi; Zhao, Huijie; Li, Xudong; Quan, Chenggen

2016-03-07

We propose a novel hyper thin 3D edge measurement technique to measure the profile of 3D outer envelope of honeycomb core structures. The width of the edges of the honeycomb core is less than 0.1 mm. We introduce a triangular layout design consisting of two cameras and one projector to measure hyper thin 3D edges and eliminate data interference from the walls. A phase-shifting algorithm and the multi-frequency heterodyne phase-unwrapping principle are applied for phase retrievals on edges. A new stereo matching method based on phase mapping and epipolar constraint is presented to solve correspondence searching on the edges and remove false matches resulting in 3D outliers. Experimental results demonstrate the effectiveness of the proposed method for measuring the 3D profile of honeycomb core structures.

In-situ calibration of nonuniformity in infrared staring and modulated systems

NASA Astrophysics Data System (ADS)

Black, Wiley T.

Infrared cameras can directly measure the apparent temperature of objects, providing thermal imaging. However, the raw output from most infrared cameras suffers from a strong, often limiting noise source called nonuniformity. Manufacturing imperfections in infrared focal planes lead to high pixel-to-pixel sensitivity to electronic bias, focal plane temperature, and other effects. The resulting imagery can only provide useful thermal imaging after a nonuniformity calibration has been performed. Traditionally, these calibrations are performed by momentarily blocking the field of view with a at temperature plate or blackbody cavity. However because the pattern is a coupling of manufactured sensitivities with operational variations, periodic recalibration is required, sometimes on the order of tens of seconds. A class of computational methods called Scene-Based Nonuniformity Correction (SBNUC) has been researched for over 20 years where the nonuniformity calibration is estimated in digital processing by analysis of the video stream in the presence of camera motion. The most sophisticated SBNUC methods can completely and robustly eliminate the high-spatial frequency component of nonuniformity with only an initial reference calibration or potentially no physical calibration. I will demonstrate a novel algorithm that advances these SBNUC techniques to support all spatial frequencies of nonuniformity correction. Long-wave infrared microgrid polarimeters are a class of camera that incorporate a microscale per-pixel wire-grid polarizer directly affixed to each pixel of the focal plane. These cameras have the capability of simultaneously measuring thermal imagery and polarization in a robust integrated package with no moving parts. I will describe the necessary adaptations of my SBNUC method to operate on this class of sensor as well as demonstrate SBNUC performance in LWIR polarimetry video collected on the UA mall.

Adaptive fusion of infrared and visible images in dynamic scene

NASA Astrophysics Data System (ADS)

Yang, Guang; Yin, Yafeng; Man, Hong; Desai, Sachi

2011-11-01

Multiple modalities sensor fusion has been widely employed in various surveillance and military applications. A variety of image fusion techniques including PCA, wavelet, curvelet and HSV has been proposed in recent years to improve human visual perception for object detection. One of the main challenges for visible and infrared image fusion is to automatically determine an optimal fusion strategy for different input scenes along with an acceptable computational cost. This paper, we propose a fast and adaptive feature selection based image fusion method to obtain high a contrast image from visible and infrared sensors for targets detection. At first, fuzzy c-means clustering is applied on the infrared image to highlight possible hotspot regions, which will be considered as potential targets' locations. After that, the region surrounding the target area is segmented as the background regions. Then image fusion is locally applied on the selected target and background regions by computing different linear combination of color components from registered visible and infrared images. After obtaining different fused images, histogram distributions are computed on these local fusion images as the fusion feature set. The variance ratio which is based on Linear Discriminative Analysis (LDA) measure is employed to sort the feature set and the most discriminative one is selected for the whole image fusion. As the feature selection is performed over time, the process will dynamically determine the most suitable feature for the image fusion in different scenes. Experiment is conducted on the OSU Color-Thermal database, and TNO Human Factor dataset. The fusion results indicate that our proposed method achieved a competitive performance compared with other fusion algorithms at a relatively low computational cost.

Direct Imaging of Shale Gas Leaks Using Passive Thermal Infrared Hyperspectral Imaging

NASA Astrophysics Data System (ADS)

Marcotte, F.; Chamberland, M.; Morton, V.; Gagnon, M. A.

2017-12-01

Natural gas is an energy resource in great demand worldwide. There are many types of gas fields including shale formations which are common especially in the St-Lawrence Valley (Qc). Regardless of its origin, methane (CH4) is the major component of natural gas. Methane gas is odorless, colorless and highly flammable. It is also an important greenhouse gas. Therefore, dealing efficiently with methane emanations and/or leaks is an important and challenging issue for both safety and environmental considerations. In this regard, passive remote sensing represents an interesting approach since it allows characterization of large areas from a safe location. The high propensity of methane contributing to global warming is mainly because it is a highly infrared-active molecule. For this reason, thermal infrared remote sensing represents one of the best approaches for methane investigations. In order to illustrate the potential of passive thermal infrared hyperspectral imaging for research on natural gas, imaging was carried out on a shale gas leak that unexpectedly happen during a geological survey near Hospital Enfant-Jésus (Québec City) in December 2014. Methane was selectively identified in the scene by its unique infrared signature. The estimated gas column density near the leak source was on the order of 65 000 ppm×m. It was estimated that the methane content in the shale gas is on the order of 6-7 %, which is in good agreement with previous geological surveys carried out in this area. Such leaks represent a very serious situation because such a methane concentration lies within the methane lower/upper explosion limits (LEL-UEL, 5-15 %). The results show how this novel technique could be used for research work dealing with methane gas.

Initial Scene Representations Facilitate Eye Movement Guidance in Visual Search

ERIC Educational Resources Information Center

Castelhano, Monica S.; Henderson, John M.

2007-01-01

What role does the initial glimpse of a scene play in subsequent eye movement guidance? In 4 experiments, a brief scene preview was followed by object search through the scene via a small moving window that was tied to fixation position. Experiment 1 demonstrated that the scene preview resulted in more efficient eye movements compared with a…

Full-field 3D shape measurement of specular object having discontinuous surfaces

NASA Astrophysics Data System (ADS)

Zhang, Zonghua; Huang, Shujun; Gao, Nan; Gao, Feng; Jiang, Xiangqian

2017-06-01

This paper presents a novel Phase Measuring Deflectometry (PMD) method to measure specular objects having discontinuous surfaces. A mathematical model is established to directly relate the absolute phase and depth, instead of the phase and gradient. Based on the model, a hardware measuring system has been set up, which consists of a precise translating stage, a projector, a diffuser and a camera. The stage locates the projector and the diffuser together to a known position during measurement. By using the model-based and machine vision methods, system calibration is accomplished to provide the required parameters and conditions. The verification tests are given to evaluate the effectiveness of the developed system. 3D (Three-Dimensional) shapes of a concave mirror and a monolithic multi-mirror array having multiple specular surfaces have been measured. Experimental results show that the proposed method can obtain 3D shape of specular objects having discontinuous surfaces effectively

Crystal structures of tiotropium bromide and its monohydrate in view of combined solid-state nuclear magnetic resonance and gauge-including projector-augmented wave studies.

PubMed

Pindelska, Edyta; Szeleszczuk, Lukasz; Pisklak, Dariusz Maciej; Majka, Zbigniew; Kolodziejski, Waclaw

2015-07-01

Tiotropium bromide is an anticholinergic bronchodilator used in the management of chronic obstructive pulmonary disease. The crystal structures of this compound and its monohydrate have been previously solved and published. However, in this paper, we showed that those structures contain some major errors. Our methodology based on combination of the solid-state nuclear magnetic resonance (NMR) spectroscopy and quantum mechanical gauge-including projector-augmented wave (GIPAW) calculations of NMR shielding constants enabled us to correct those errors and obtain reliable structures of the studied compounds. It has been proved that such approach can be used not only to perform the structural analysis of a drug substance and to identify its polymorphs, but also to verify and optimize already existing crystal structures. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

"Black Magic": Pepper in a Magnetic Field

ERIC Educational Resources Information Center

Peterson, John E.

1977-01-01

Describes a procedure to demonstrate the effect of a magnetic force on a moving charge. The materials used are inexpensive and with the use of an overhead projector, easily visible to an entire class. (CP)

A novel wide-field-of-view display method with higher central resolution for hyper-realistic head dome projector

NASA Astrophysics Data System (ADS)

Hotta, Aira; Sasaki, Takashi; Okumura, Haruhiko

2007-02-01

In this paper, we propose a novel display method to realize a high-resolution image in a central visual field for a hyper-realistic head dome projector. The method uses image processing based on the characteristics of human vision, namely, high central visual acuity and low peripheral visual acuity, and pixel shift technology, which is one of the resolution-enhancing technologies for projectors. The projected image with our method is a fine wide-viewing-angle image with high definition in the central visual field. We evaluated the psychological effects of the projected images with our method in terms of sensation of reality. According to the result, we obtained 1.5 times higher resolution in the central visual field and a greater sensation of reality by using our method.

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

Caravelli, Francesco

The dynamics of purely memristive circuits has been shown to depend on a projection operator which expresses the Kirchhoff constraints, is naturally non-local in nature, and does represent the interaction between memristors. In the present paper we show that for the case of planar circuits, for which a meaningful Hamming distance can be defined, the elements of such projector can be bounded by exponentially decreasing functions of the distance. We provide a geometrical interpretation of the projector elements in terms of determinants of Dirichlet Laplacian of the dual circuit. For the case of linearized dynamics of the circuit for whichmore » a solution is known, this can be shown to provide a light cone bound for the interaction between memristors. Furthermore, this result establishes a finite speed of propagation of signals across the network, despite the non-local nature of the system.« less

Interactive display system having a digital micromirror imaging device

DOEpatents

Veligdan, James T.; DeSanto, Leonard; Kaull, Lisa; Brewster, Calvin

2006-04-11

A display system includes a waveguide optical panel having an inlet face and an opposite outlet face. A projector cooperates with a digital imaging device, e.g. a digital micromirror imaging device, for projecting an image through the panel for display on the outlet face. The imaging device includes an array of mirrors tiltable between opposite display and divert positions. The display positions reflect an image light beam from the projector through the panel for display on the outlet face. The divert positions divert the image light beam away from the panel, and are additionally used for reflecting a probe light beam through the panel toward the outlet face. Covering a spot on the panel, e.g. with a finger, reflects the probe light beam back through the panel toward the inlet face for detection thereat and providing interactive capability.

A novel scene management technology for complex virtual battlefield environment

NASA Astrophysics Data System (ADS)

Sheng, Changchong; Jiang, Libing; Tang, Bo; Tang, Xiaoan

2018-04-01

The efficient scene management of virtual environment is an important research content of computer real-time visualization, which has a decisive influence on the efficiency of drawing. However, Traditional scene management methods do not suitable for complex virtual battlefield environments, this paper combines the advantages of traditional scene graph technology and spatial data structure method, using the idea of management and rendering separation, a loose object-oriented scene graph structure is established to manage the entity model data in the scene, and the performance-based quad-tree structure is created for traversing and rendering. In addition, the collaborative update relationship between the above two structural trees is designed to achieve efficient scene management. Compared with the previous scene management method, this method is more efficient and meets the needs of real-time visualization.

Tinkertoy Color-Addition Device.

ERIC Educational Resources Information Center

Ferguson, Joe L.

1995-01-01

Describes construction and use of a simple home-built device, using an overhead projector, for use in demonstrations of the addition of various combinations of red, green, and blue light. Useful in connection with discussions of color, color vision, or color television. (JRH)

Topological susceptibility from twisted mass fermions using spectral projectors and the gradient flow

NASA Astrophysics Data System (ADS)

Alexandrou, Constantia; Athenodorou, Andreas; Cichy, Krzysztof; Constantinou, Martha; Horkel, Derek P.; Jansen, Karl; Koutsou, Giannis; Larkin, Conor

2018-04-01

We compare lattice QCD determinations of topological susceptibility using a gluonic definition from the gradient flow and a fermionic definition from the spectral-projector method. We use ensembles with dynamical light, strange and charm flavors of maximally twisted mass fermions. For both definitions of the susceptibility we employ ensembles at three values of the lattice spacing and several quark masses at each spacing. The data are fitted to chiral perturbation theory predictions with a discretization term to determine the continuum chiral condensate in the massless limit and estimate the overall discretization errors. We find that both approaches lead to compatible results in the continuum limit, but the gluonic ones are much more affected by cutoff effects. This finally yields a much smaller total error in the spectral-projector results. We show that there exists, in principle, a value of the spectral cutoff which would completely eliminate discretization effects in the topological susceptibility.

Design of a linear projector for use with the normal modes of the GLAS 4th order GCM

NASA Technical Reports Server (NTRS)

Bloom, S. C.

1984-01-01

The design of a linear projector for use with the normal modes of a model of atmospheric circulation is discussed. A central element in any normal mode initialization scheme is the process by which a set of data fields - winds, temperatures or geopotentials, and surface pressures - are expressed ("projected') in terms of the coefficients of a model's normal modes. This process is completely analogous to the Fourier decomposition of a single field (indeed a FFT applied in the zonal direction is a part of the process). Complete separability in all three spatial dimensions is assumed. The basis functions for the modal expansion are given. An important feature of the normal modes is their coupling of the structures of different fields, thus a coefficient in a normal mode expansion would contain both mass and momentum information.

Evaluation of expansion algorithm of measurement range suited for 3D shape measurement using two pitches of projected grating with light source-stepping method

NASA Astrophysics Data System (ADS)

Sakaguchi, Toshimasa; Fujigaki, Motoharu; Murata, Yorinobu

2015-03-01

Accurate and wide-range shape measurement method is required in industrial field. The same technique is possible to be used for a shape measurement of a human body for the garment industry. Compact 3D shape measurement equipment is also required for embedding in the inspection system. A shape measurement by a phase shifting method can measure the shape with high spatial resolution because the coordinates can be obtained pixel by pixel. A key-device to develop compact equipment is a grating projector. Authors developed a linear LED projector and proposed a light source stepping method (LSSM) using the linear LED projector. The shape measurement euipment can be produced with low-cost and compact without any phase-shifting mechanical systems by using this method. Also it enables us to measure 3D shape in very short time by switching the light sources quickly. A phase unwrapping method is necessary to widen the measurement range with constant accuracy for phase shifting method. A general phase unwrapping method with difference grating pitches is often used. It is one of a simple phase unwrapping method. It is, however, difficult to apply the conventional phase unwrapping algorithm to the LSSM. Authors, therefore, developed an expansion unwrapping algorithm for the LSSM. In this paper, an expansion algorithm of measurement range suited for 3D shape measurement using two pitches of projected grating with the LSSM was evaluated.