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Sample records for acquire digital images

  1. Methods for identification of images acquired with digital cameras

    NASA Astrophysics Data System (ADS)

    Geradts, Zeno J.; Bijhold, Jurrien; Kieft, Martijn; Kurosawa, Kenji; Kuroki, Kenro; Saitoh, Naoki

    2001-02-01

    From the court we were asked whether it is possible to determine if an image has been made with a specific digital camera. This question has to be answered in child pornography cases, where evidence is needed that a certain picture has been made with a specific camera. We have looked into different methods of examining the cameras to determine if a specific image has been made with a camera: defects in CCDs, file formats that are used, noise introduced by the pixel arrays and watermarking in images used by the camera manufacturer.

  2. Quality of images acquired with and without grid in digital mammography.

    PubMed

    Al Khalifah, Khaled H; Brindhaban, Ajit; Saeed, Raed A

    2014-01-01

    In this study, we assessed the quality of digital mammography images acquired with a grid and without a grid for different kVp values. A digital mammography system was used for acquisition of images of the CIRS Model 015 Mammography Accreditation Phantom. The images were obtained in the presence of the grid and then with the grid removed from the system. The energy of the X-rays was varied between 26 and 32 kVp. The images were evaluated by five senior radiologic technologists with extensive experience in mammography. Statistical analysis was carried out with the Mann-Whitney non-parametric test with the level of significance set at p = 0.05. The comparison between images obtained with a grid and without a grid indicated that, for the visibility of fibers, the non-grid images at 28 kVp were significantly (p = 0.032) better than the images acquired with a grid. At all other kVp values, the images were not statistically different regarding the visibility of fibers. For the visibility of specks and masses, the images did not show any significant differences at any of the kVp values of the study. Imaging with kVp higher than 30 requires a grid to improve the visibility of fibrous calcifications and specks. For the visibility of masses at 32 kVp, no statistically significant differences between the grid and non-grid images were found.

  3. Optimal angular dose distribution to acquire 3D and extra 2D images for digital breast tomosynthesis (DBT)

    NASA Astrophysics Data System (ADS)

    Park, Hye-Suk; Kim, Ye-Seul; Lee, Haeng-Hwa; Gang, Won-Suk; Kim, Hee-Joung; Choi, Young-Wook; Choi, JaeGu

    2015-08-01

    The purpose of this study is to determine the optimal non-uniform angular dose distribution to improve the quality of the 3D reconstructed images and to acquire extra 2D projection images. In this analysis, 7 acquisition sets were generated by using four different values for the number of projections (11, 15, 21, and 29) and total angular range (±14°, ±17.5°, ±21°, and ±24.5° ). For all acquisition sets, the zero-degree projection was used as the 2D image that was close to that of standard conventional mammography (CM). Exposures used were 50, 100, 150, and 200 mR for the zero-degree projection, and the remaining dose was distributed over the remaining projection angles. To quantitatively evaluate image quality, we computed the CNR (contrast-to-noise ratio) and the ASF (artifact spread function) for the same radiation dose. The results indicate that, for microcalcifications, acquisition sets with approximately 4 times higher exposure on the zero-degree projection than the average exposure for the remaining projection angles yielded higher CNR values and were 3% higher than the uniform distribution. However, very high dose concentrations toward the zero-degree projection may reduce the quality of the reconstructed images due to increasing noise in the peripheral views. The zero-degree projection of the non-uniform dose distribution offers a 2D image similar to that of standard CM, but with a significantly lower radiation dose. Therefore, we need to evaluate the diagnostic potential of extra 2D projection image when diagnose breast cancer by using 3D images with non-uniform angular dose distributions.

  4. Digital Imaging Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bamberger, Casimir; Renz, Uwe; Bamberger, Andreas

    2011-06-01

    Methods to visualize the two-dimensional (2D) distribution of molecules by mass spectrometric imaging evolve rapidly and yield novel applications in biology, medicine, and material surface sciences. Most mass spectrometric imagers acquire high mass resolution spectra spot-by-spot and thereby scan the object's surface. Thus, imaging is slow and image reconstruction remains cumbersome. Here we describe an imaging mass spectrometer that exploits the true imaging capabilities by ion optical means for the time of flight mass separation. The mass spectrometer is equipped with the ASIC Timepix chip as an array detector to acquire the position, mass, and intensity of ions that are imaged by matrix-assisted laser desorption/ionization (MALDI) directly from the target sample onto the detector. This imaging mass spectrometer has a spatial resolving power at the specimen of (84 ± 35) μm with a mass resolution of 45 and locates atoms or organic compounds on a surface area up to ~2 cm2. Extended laser spots of ~5 mm2 on structured specimens allows parallel imaging of selected masses. The digital imaging mass spectrometer proves high hit-multiplicity, straightforward image reconstruction, and potential for high-speed readout at 4 kHz or more. This device demonstrates a simple way of true image acquisition like a digital photographic camera. The technology may enable a fast analysis of biomolecular samples in near future.

  5. A method to produce and validate a digitally reconstructed radiograph-based computer simulation for optimisation of chest radiographs acquired with a computed radiography imaging system

    PubMed Central

    Moore, C S; Liney, G P; Beavis, A W; Saunderson, J R

    2011-01-01

    Objectives The purpose of this study was to develop and validate a computer model to produce realistic simulated computed radiography (CR) chest images using CT data sets of real patients. Methods Anatomical noise, which is the limiting factor in determining pathology in chest radiography, is realistically simulated by the CT data, and frequency-dependent noise has been added post-digitally reconstructed radiograph (DRR) generation to simulate exposure reduction. Realistic scatter and scatter fractions were measured in images of a chest phantom acquired on the CR system simulated by the computer model and added post-DRR calculation. Results The model has been validated with a phantom and patients and shown to provide predictions of signal-to-noise ratios (SNRs), tissue-to-rib ratios (TRRs: a measure of soft tissue pixel value to that of rib) and pixel value histograms that lie within the range of values measured with patients and the phantom. The maximum difference in measured SNR to that calculated was 10%. TRR values differed by a maximum of 1.3%. Conclusion Experienced image evaluators have responded positively to the DRR images, are satisfied they contain adequate anatomical features and have deemed them clinically acceptable. Therefore, the computer model can be used by image evaluators to grade chest images presented at different tube potentials and doses in order to optimise image quality and patient dose for clinical CR chest radiographs without the need for repeat patient exposures. PMID:21933979

  6. A comparison of the precision of three-dimensional images acquired by 2 digital intraoral scanners: effects of tooth irregularity and scanning direction

    PubMed Central

    Anh, Ji-won; Park, Ji-Man; Chun, Youn-Sic; Kim, Miae

    2016-01-01

    Objective The purpose of this study was to compare the precision of three-dimensional (3D) images acquired using iTero® (Align Technology Inc., San Jose, CA, USA) and Trios® (3Shape Dental Systems, Copenhagen, Denmark) digital intraoral scanners, and to evaluate the effects of the severity of tooth irregularities and scanning sequence on precision. Methods Dental arch models were fabricated with differing degrees of tooth irregularity and divided into 2 groups based on scanning sequence. To assess their precision, images were superimposed and an optimized superimposition algorithm was employed to measure any 3D deviation. The t-test, paired t-test, and one-way ANOVA were performed (p < 0.05) for statistical analysis. Results The iTero® and Trios® systems showed no statistically significant difference in precision among models with differing degrees of tooth irregularity. However, there were statistically significant differences in the precision of the 2 scanners when the starting points of scanning were different. The iTero® scanner (mean deviation, 29.84 ± 12.08 µm) proved to be less precise than the Trios® scanner (22.17 ± 4.47 µm). Conclusions The precision of 3D images differed according to the degree of tooth irregularity, scanning sequence, and scanner type. However, from a clinical standpoint, both scanners were highly accurate regardless of the degree of tooth irregularity. PMID:26877977

  7. Point cloud generation from aerial image data acquired by a quadrocopter type micro unmanned aerial vehicle and a digital still camera.

    PubMed

    Rosnell, Tomi; Honkavaara, Eija

    2012-01-01

    The objective of this investigation was to develop and investigate methods for point cloud generation by image matching using aerial image data collected by quadrocopter type micro unmanned aerial vehicle (UAV) imaging systems. Automatic generation of high-quality, dense point clouds from digital images by image matching is a recent, cutting-edge step forward in digital photogrammetric technology. The major components of the system for point cloud generation are a UAV imaging system, an image data collection process using high image overlaps, and post-processing with image orientation and point cloud generation. Two post-processing approaches were developed: one of the methods is based on Bae Systems' SOCET SET classical commercial photogrammetric software and another is built using Microsoft(®)'s Photosynth™ service available in the Internet. Empirical testing was carried out in two test areas. Photosynth processing showed that it is possible to orient the images and generate point clouds fully automatically without any a priori orientation information or interactive work. The photogrammetric processing line provided dense and accurate point clouds that followed the theoretical principles of photogrammetry, but also some artifacts were detected. The point clouds from the Photosynth processing were sparser and noisier, which is to a large extent due to the fact that the method is not optimized for dense point cloud generation. Careful photogrammetric processing with self-calibration is required to achieve the highest accuracy. Our results demonstrate the high performance potential of the approach and that with rigorous processing it is possible to reach results that are consistent with theory. We also point out several further research topics. Based on theoretical and empirical results, we give recommendations for properties of imaging sensor, data collection and processing of UAV image data to ensure accurate point cloud generation.

  8. Point Cloud Generation from Aerial Image Data Acquired by a Quadrocopter Type Micro Unmanned Aerial Vehicle and a Digital Still Camera

    PubMed Central

    Rosnell, Tomi; Honkavaara, Eija

    2012-01-01

    The objective of this investigation was to develop and investigate methods for point cloud generation by image matching using aerial image data collected by quadrocopter type micro unmanned aerial vehicle (UAV) imaging systems. Automatic generation of high-quality, dense point clouds from digital images by image matching is a recent, cutting-edge step forward in digital photogrammetric technology. The major components of the system for point cloud generation are a UAV imaging system, an image data collection process using high image overlaps, and post-processing with image orientation and point cloud generation. Two post-processing approaches were developed: one of the methods is based on Bae Systems’ SOCET SET classical commercial photogrammetric software and another is built using Microsoft®’s Photosynth™ service available in the Internet. Empirical testing was carried out in two test areas. Photosynth processing showed that it is possible to orient the images and generate point clouds fully automatically without any a priori orientation information or interactive work. The photogrammetric processing line provided dense and accurate point clouds that followed the theoretical principles of photogrammetry, but also some artifacts were detected. The point clouds from the Photosynth processing were sparser and noisier, which is to a large extent due to the fact that the method is not optimized for dense point cloud generation. Careful photogrammetric processing with self-calibration is required to achieve the highest accuracy. Our results demonstrate the high performance potential of the approach and that with rigorous processing it is possible to reach results that are consistent with theory. We also point out several further research topics. Based on theoretical and empirical results, we give recommendations for properties of imaging sensor, data collection and processing of UAV image data to ensure accurate point cloud generation. PMID:22368479

  9. Point cloud generation from aerial image data acquired by a quadrocopter type micro unmanned aerial vehicle and a digital still camera.

    PubMed

    Rosnell, Tomi; Honkavaara, Eija

    2012-01-01

    The objective of this investigation was to develop and investigate methods for point cloud generation by image matching using aerial image data collected by quadrocopter type micro unmanned aerial vehicle (UAV) imaging systems. Automatic generation of high-quality, dense point clouds from digital images by image matching is a recent, cutting-edge step forward in digital photogrammetric technology. The major components of the system for point cloud generation are a UAV imaging system, an image data collection process using high image overlaps, and post-processing with image orientation and point cloud generation. Two post-processing approaches were developed: one of the methods is based on Bae Systems' SOCET SET classical commercial photogrammetric software and another is built using Microsoft(®)'s Photosynth™ service available in the Internet. Empirical testing was carried out in two test areas. Photosynth processing showed that it is possible to orient the images and generate point clouds fully automatically without any a priori orientation information or interactive work. The photogrammetric processing line provided dense and accurate point clouds that followed the theoretical principles of photogrammetry, but also some artifacts were detected. The point clouds from the Photosynth processing were sparser and noisier, which is to a large extent due to the fact that the method is not optimized for dense point cloud generation. Careful photogrammetric processing with self-calibration is required to achieve the highest accuracy. Our results demonstrate the high performance potential of the approach and that with rigorous processing it is possible to reach results that are consistent with theory. We also point out several further research topics. Based on theoretical and empirical results, we give recommendations for properties of imaging sensor, data collection and processing of UAV image data to ensure accurate point cloud generation. PMID:22368479

  10. Digital Image Access & Retrieval.

    ERIC Educational Resources Information Center

    Heidorn, P. Bryan, Ed.; Sandore, Beth, Ed.

    Recent technological advances in computing and digital imaging technology have had immediate and permanent consequences for visual resource collections. Libraries are involved in organizing and managing large visual resource collections. The central challenges in working with digital image collections mirror those that libraries have sought to…

  11. Digital Image Correlation Engine

    SciTech Connect

    Turner, Dan; Crozier, Paul; Reu, Phil

    2015-10-06

    DICe is an open source digital image correlation (DIC) tool intended for use as a module in an external application or as a standalone analysis code. It's primary capability is computing full –field displacements and strains from sequences of digital These images are typically of a material sample undergoing a materials characterization experiment, but DICe is also useful for other applications (for example, trajectory tracking). DICe is machine portable (Windows, Linux and Mac) and can be effectively deployed on a high performance computing platform. Capabilities from DICe can be invoked through a library interface, via source code integration of DICe classes or through a graphical user interface.

  12. Digital image processing.

    PubMed

    Lo, Winnie Y; Puchalski, Sarah M

    2008-01-01

    Image processing or digital image manipulation is one of the greatest advantages of digital radiography (DR). Preprocessing depends on the modality and corrects for system irregularities such as differential light detection efficiency, dead pixels, or dark noise. Processing is manipulation of the raw data just after acquisition. It is generally proprietary and specific to the DR vendor but encompasses manipulations such as unsharp mask filtering within two or more spatial frequency bands, histogram sliding and stretching, and gray scale rendition or lookup table application. These processing steps have a profound effect on the final appearance of the radiograph, but they can also lead to artifacts unique to digital systems. Postprocessing refers to manipulation of the final appearance of the radiograph by the end-user and does not involve alteration of the raw data.

  13. Light microscopy digital imaging.

    PubMed

    Joubert, James; Sharma, Deepak

    2011-10-01

    This unit presents an overview of digital imaging hardware used in light microscopy. CMOS, CCD, and EMCCDs are the primary sensors used. The strengths and weaknesses of each define the primary applications for these sensors. Sensor architecture and formats are also reviewed. Color camera design strategies and sensor window cleaning are also described in the unit.

  14. Method for acquiring, storing and analyzing crystal images

    NASA Technical Reports Server (NTRS)

    Gester, Thomas E. (Inventor); Rosenblum, William M. (Inventor); Christopher, Gayle K. (Inventor); Hamrick, David T. (Inventor); Delucas, Lawrence J. (Inventor); Tillotson, Brian (Inventor)

    2003-01-01

    A system utilizing a digital computer for acquiring, storing and evaluating crystal images. The system includes a video camera (12) which produces a digital output signal representative of a crystal specimen positioned within its focal window (16). The digitized output from the camera (12) is then stored on data storage media (32) together with other parameters inputted by a technician and relevant to the crystal specimen. Preferably, the digitized images are stored on removable media (32) while the parameters for different crystal specimens are maintained in a database (40) with indices to the digitized optical images on the other data storage media (32). Computer software is then utilized to identify not only the presence and number of crystals and the edges of the crystal specimens from the optical image, but to also rate the crystal specimens by various parameters, such as edge straightness, polygon formation, aspect ratio, surface clarity, crystal cracks and other defects or lack thereof, and other parameters relevant to the quality of the crystals.

  15. Digital imaging in dentistry.

    PubMed

    Essen, S Donovan

    2011-01-01

    Information technology is vital to operations, marketing, accounting, finance and administration. One of the most exciting and quickly evolving technologies in the modern dental office is digital applications. The dentist is often the business manager, information technology officer and strategic planning chief for his small business. The information systems triangle applies directly to this critical manager supported by properly trained ancillary staff and good equipment. With emerging technology driving all medical disciplines and the rapid pace at which it emerges, it is vital for the contemporary practitioner to keep abreast of the newest information technology developments. This article compares the strategic and operational advantages of digital applications, specifically imaging. The focus of this paper will be on digital radiography (DR), 3D computerized tomography, digital photography and digitally-driven CAD/CAM to what are now considered obsolescing modalities and contemplates what may arrive in the future. It is the purpose of this essay to succinctly evaluate the decisions involved in the role, application and implications of employing this tool in the dental environment PMID:22132658

  16. Digital imaging in dentistry.

    PubMed

    Essen, S Donovan

    2011-01-01

    Information technology is vital to operations, marketing, accounting, finance and administration. One of the most exciting and quickly evolving technologies in the modern dental office is digital applications. The dentist is often the business manager, information technology officer and strategic planning chief for his small business. The information systems triangle applies directly to this critical manager supported by properly trained ancillary staff and good equipment. With emerging technology driving all medical disciplines and the rapid pace at which it emerges, it is vital for the contemporary practitioner to keep abreast of the newest information technology developments. This article compares the strategic and operational advantages of digital applications, specifically imaging. The focus of this paper will be on digital radiography (DR), 3D computerized tomography, digital photography and digitally-driven CAD/CAM to what are now considered obsolescing modalities and contemplates what may arrive in the future. It is the purpose of this essay to succinctly evaluate the decisions involved in the role, application and implications of employing this tool in the dental environment

  17. Digital Image Correlation Engine

    2015-10-06

    DICe is an open source digital image correlation (DIC) tool intended for use as a module in an external application or as a standalone analysis code. It's primary capability is computing full –field displacements and strains from sequences of digital These images are typically of a material sample undergoing a materials characterization experiment, but DICe is also useful for other applications (for example, trajectory tracking). DICe is machine portable (Windows, Linux and Mac) and canmore » be effectively deployed on a high performance computing platform. Capabilities from DICe can be invoked through a library interface, via source code integration of DICe classes or through a graphical user interface.« less

  18. Acquired portosystemic collaterals: anatomy and imaging*

    PubMed Central

    Leite, Andréa Farias de Melo; Mota Jr., Américo; Chagas-Neto, Francisco Abaeté; Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco

    2016-01-01

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common-increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations. PMID:27777479

  19. The Apollo Digital Image Archive: Project Status

    NASA Astrophysics Data System (ADS)

    Paris, K. N.; Robinson, M. S.; Lawrence, S. J.; Danton, J.; Bowman-Cisneros, E.; Licht, A.; Close, W.; Ingram, R.

    2012-03-01

    Photographs acquired by the Apollo astronauts are currently being scanned at JSC and the files sent to ASU for the Apollo Digital Image Archive. The metric frames are nearing completion while the panoramic frames are in the process of being released.

  20. A novel digital magnetic resonance imaging spectrometer.

    PubMed

    Liu, Zhengmin; Zhao, Cong; Zhou, Heqin; Feng, Huanqing

    2006-01-01

    Spectrometer is the essential part of magnetic resonance imaging (MRI) system. It controls the transmitting and receiving of signals. Many commercial spectrometers are now available. However, they are usually costly and complex. In this paper, a new digital spectrometer based on PCI extensions for instrumentation (PXI) architecture is presented. Radio frequency (RF) pulse is generated with the method of digital synthesis and its frequency and phase are continuously tunable. MR signal acquired by receiver coils is processed by digital quadrature detection and filtered to get the k-space data, which avoid the spectral distortion due to amplitude and phase errors between two channels of traditional detection. Compared to the conventional design, the presented spectrometer is built with general PXI platform and boards. This design works in a digital manner with features of low cost, high performance and accuracy. The experiments demonstrate its efficiency.

  1. Reversible digital images

    NASA Astrophysics Data System (ADS)

    Knox, Keith T.

    1999-04-01

    A method has been developed to hide one image inside another with little loss in image quality. If the second image is a logo or watermark, then this method may be used to protect the ownership rights of the first image and to guarantee the authenticity of the image. The two images to be combined may be either black & white or color continuous tone images. A reversible image is created by incorporating the first image in the upper 4 bits and the second image in the lower 4 bits. When viewed normally, the reversible image appears to be the first image. To view the hidden image, the bits of the combined image are reversed, exchanging all of the lower and higher order bits. When viewed in the reversed mode, the image appears to be the second or hidden image. To maintain a high level of image quality for both images, two simultaneous error diffusion calculations are run to ensure that both views of the reversible image have the same visual appearance as the originals. Any alteration of one of the images locally destroys the other image at the site of the alterations. This provides a method to detect alterations of the original image.

  2. Image processing in digital radiography.

    PubMed

    Freedman, M T; Artz, D S

    1997-01-01

    Image processing is a critical part of obtaining high-quality digital radiographs. Fortunately, the user of these systems does not need to understand image processing in detail, because the manufacturers provide good starting values. Because radiologists may have different preferences in image appearance, it is helpful to know that many aspects of image appearance can be changed by image processing, and a new preferred setting can be loaded into the computer and saved so that it can become the new standard processing method. Image processing allows one to change the overall optical density of an image and to change its contrast. Spatial frequency processing allows an image to be sharpened, improving its appearance. It also allows noise to be blurred so that it is less visible. Care is necessary to avoid the introduction of artifacts or the hiding of mediastinal tubes.

  3. Detecting jaundice by using digital image processing

    NASA Astrophysics Data System (ADS)

    Castro-Ramos, J.; Toxqui-Quitl, C.; Villa Manriquez, F.; Orozco-Guillen, E.; Padilla-Vivanco, A.; Sánchez-Escobar, JJ.

    2014-03-01

    When strong Jaundice is presented, babies or adults should be subject to clinical exam like "serum bilirubin" which can cause traumas in patients. Often jaundice is presented in liver disease such as hepatitis or liver cancer. In order to avoid additional traumas we propose to detect jaundice (icterus) in newborns or adults by using a not pain method. By acquiring digital images in color, in palm, soles and forehead, we analyze RGB attributes and diffuse reflectance spectra as the parameter to characterize patients with either jaundice or not, and we correlate that parameters with the level of bilirubin. By applying support vector machine we distinguish between healthy and sick patients.

  4. Feature-Based Digital Watermarking for Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Hsu, P.-H.; Chen, C.-C.

    2012-08-01

    With the rapid development of information and communication technology, people can acquire and distribute many kinds of digital data more conveniently than before. The consequence is that the "copyright protection" which prevents digital data from been duplicated illegally should be paid much more attention. Digital watermarking is the process of embedding visible or invisible information into a digital signal which may be used to verify its authenticity or the identity of its owners. In the past, digital watermarking technology has been successfully applied to the "copyright protection" of multimedia data, however the researches and applications of applying digital watermarking to geo-information data are still very inadequate. In this study, a novel digital watermarking algorithm based on the scale-space feature points is applied to the remote sensing images, and the robustness of the embedded digital watermark and the impact on satellite image quality are evaluated and analysed. This kind of feature points are commonly invariant to Image rotation, scaling and translation, therefore they naturally fit into the requirement of geometrically robust image watermarking. The experiment results show almost all extracted watermarks have high values of normal correlation and can be recognized clearly after the processing of image compression, brightness adjustment and contrast adjustment. In addition, most of the extracted watermarks are identified after the geometric attacks. Furthermore, the unsupervised image classification is implemented on the watermarked images to evaluate the image quality reduction and the results show that classification accuracy is affected slightly after embedding watermarks into the satellite images.

  5. Three-dimensional digital breast histopathology imaging

    NASA Astrophysics Data System (ADS)

    Clarke, G. M.; Peressotti, C.; Mawdsley, G. E.; Eidt, S.; Ge, M.; Morgan, T.; Zubovits, J. T.; Yaffe, M. J.

    2005-04-01

    We have developed a digital histology imaging system that has the potential to improve the accuracy of surgical margin assessment in the treatment of breast cancer by providing finer sampling and 3D visualization. The system is capable of producing a 3D representation of histopathology from an entire lumpectomy specimen. We acquire digital photomicrographs of a stack of large (120 x 170 mm) histology slides cut serially through the entire specimen. The images are then registered and displayed in 2D and 3D. This approach dramatically improves sampling and can improve visualization of tissue structures compared to current, small-format histology. The system consists of a brightfield microscope, adapted with a freeze-frame digital video camera and a large, motorized translation stage. The image of each slide is acquired as a mosaic of adjacent tiles, each tile representing one field-of-view of the microscope, and the mosaic is assembled into a seamless composite image. The assembly is done by a program developed to build image sets at six different levels within a multiresolution pyramid. A database-linked viewing program has been created to efficiently register and display the animated stack of images, which occupies about 80 GB of disk space per lumpectomy at full resolution, on a high-resolution (3840 x 2400 pixels) colour monitor. The scanning or tiling approach to digitization is inherently susceptible to two artefacts which disrupt the composite image, and which impose more stringent requirements on system performance. Although non-uniform illumination across any one isolated tile may not be discernible, the eye readily detects this non-uniformity when the entire assembly of tiles is viewed. The pattern is caused by deficiencies in optical alignment, spectrum of the light source, or camera corrections. The imaging task requires that features as small as 3.2 &mum in extent be seamlessly preserved. However, inadequate accuracy in positioning of the translation

  6. An image-guided tool to prevent hospital acquired infections

    NASA Astrophysics Data System (ADS)

    Nagy, Melinda; Szilágyi, László; Lehotsky, Ákos; Haidegger, Tamás; Benyó, Balázs

    2011-03-01

    Hospital Acquired Infections (HAI) represent the fourth leading cause of death in the United States, and claims hundreds of thousands of lives annually in the rest of the world. This paper presents a novel low-cost mobile device|called Stery-Hand|that helps to avoid HAI by improving hand hygiene control through providing an objective evaluation of the quality of hand washing. The use of the system is intuitive: having performed hand washing with a soap mixed with UV re ective powder, the skin appears brighter in UV illumination on the disinfected surfaces. Washed hands are inserted into the Stery-Hand box, where a digital image is taken under UV lighting. Automated image processing algorithms are employed in three steps to evaluate the quality of hand washing. First, the contour of the hand is extracted in order to distinguish the hand from the background. Next, a semi-supervised clustering algorithm classies the pixels of the hand into three groups, corresponding to clean, partially clean and dirty areas. The clustering algorithm is derived from the histogram-based quick fuzzy c-means approach, using a priori information extracted from reference images, evaluated by experts. Finally, the identied areas are adjusted to suppress shading eects, and quantied in order to give a verdict on hand disinfection quality. The proposed methodology was validated through tests using hundreds of images recorded in our laboratory. The proposed system was found robust and accurate, producing correct estimation for over 98% of the test cases. Stery-Hand may be employed in general practice, and it may also serve educational purposes.

  7. Digital imaging analysis to assess scar phenotype.

    PubMed

    Smith, Brian J; Nidey, Nichole; Miller, Steven F; Moreno Uribe, Lina M; Baum, Christian L; Hamilton, Grant S; Wehby, George L; Dunnwald, Martine

    2014-01-01

    In order to understand the link between the genetic background of patients and wound clinical outcomes, it is critical to have a reliable method to assess the phenotypic characteristics of healed wounds. In this study, we present a novel imaging method that provides reproducible, sensitive, and unbiased assessments of postsurgical scarring. We used this approach to investigate the possibility that genetic variants in orofacial clefting genes are associated with suboptimal healing. Red-green-blue digital images of postsurgical scars of 68 patients, following unilateral cleft lip repair, were captured using the 3dMD imaging system. Morphometric and colorimetric data of repaired regions of the philtrum and upper lip were acquired using ImageJ software, and the unaffected contralateral regions were used as patient-specific controls. Repeatability of the method was high with intraclass correlation coefficient score > 0.8. This method detected a very significant difference in all three colors, and for all patients, between the scarred and the contralateral unaffected philtrum (p ranging from 1.20(-05) to 1.95(-14) ). Physicians' clinical outcome ratings from the same images showed high interobserver variability (overall Pearson coefficient = 0.49) as well as low correlation with digital image analysis results. Finally, we identified genetic variants in TGFB3 and ARHGAP29 associated with suboptimal healing outcome.

  8. Digital imaging analysis to assess scar phenotype

    PubMed Central

    Smith, Brian J.; Nidey, Nichole; Miller, Steven F.; Moreno, Lina M.; Baum, Christian L.; Hamilton, Grant S.; Wehby, George L.; Dunnwald, Martine

    2015-01-01

    In order to understand the link between the genetic background of patients and wound clinical outcomes, it is critical to have a reliable method to assess the phenotypic characteristics of healed wounds. In this study, we present a novel imaging method that provides reproducible, sensitive and unbiased assessments of post-surgical scarring. We used this approach to investigate the possibility that genetic variants in orofacial clefting genes are associated with suboptimal healing. Red-green-blue (RGB) digital images of post-surgical scars of 68 patients, following unilateral cleft lip repair, were captured using the 3dMD image system. Morphometric and colorimetric data of repaired regions of the philtrum and upper lip were acquired using ImageJ software and the unaffected contralateral regions were used as patient-specific controls. Repeatability of the method was high with interclass correlation coefficient score > 0.8. This method detected a very significant difference in all three colors, and for all patients, between the scarred and the contralateral unaffected philtrum (P ranging from 1.20−05 to 1.95−14). Physicians’ clinical outcome ratings from the same images showed high inter-observer variability (overall Pearson coefficient = 0.49) as well as low correlation with digital image analysis results. Finally, we identified genetic variants in TGFB3 and ARHGAP29 associated with suboptimal healing outcome. PMID:24635173

  9. Digital imaging-based retinal photocoagulation system

    NASA Astrophysics Data System (ADS)

    Barrett, Steven F.; Wright, Cameron H. G.; Oberg, Erik D.; Rockwell, Benjamin A.; Cain, Clarence P.; Rylander, Henry G., III; Welch, Ashley J.

    1997-05-01

    Researchers at the USAF Academy and the University of Texas are developing a computer-assisted retinal photocoagulation system for the treatment of retinal disorders (i.e. diabetic retinopathy, retinal tears). Currently, ophthalmologists manually place therapeutic retinal lesions, an acquired technique that is tiring for both the patient and physician. The computer-assisted system under development can rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a matter of seconds. Separate prototype subsystems have been developed to control lesion depth during irradiation and lesion placement to compensate for retinal movement. Both subsystems have been successfully demonstrated in vivo on pigmented rabbits using an argon continuous wave laser. Two different design approaches are being pursued to combine the capabilities of both subsystems: a digital imaging-based system and a hybrid analog-digital system. This paper will focus on progress with the digital imaging-based prototype system. A separate paper on the hybrid analog-digital system, `Hybrid Retinal Photocoagulation System', is also presented in this session.

  10. An Experimental Digital Image Processor

    NASA Astrophysics Data System (ADS)

    Cok, Ronald S.

    1986-12-01

    A prototype digital image processor for enhancing photographic images has been built in the Research Laboratories at Kodak. This image processor implements a particular version of each of the following algorithms: photographic grain and noise removal, edge sharpening, multidimensional image-segmentation, image-tone reproduction adjustment, and image-color saturation adjustment. All processing, except for segmentation and analysis, is performed by massively parallel and pipelined special-purpose hardware. This hardware runs at 10 MHz and can be adjusted to handle any size digital image. The segmentation circuits run at 30 MHz. The segmentation data are used by three single-board computers for calculating the tonescale adjustment curves. The system, as a whole, has the capability of completely processing 10 million three-color pixels per second. The grain removal and edge enhancement algorithms represent the largest part of the pipelined hardware, operating at over 8 billion integer operations per second. The edge enhancement is performed by unsharp masking, and the grain removal is done using a collapsed Walsh-hadamard transform filtering technique (U.S. Patent No. 4549212). These two algo-rithms can be realized using four basic processing elements, some of which have been imple-mented as VLSI semicustom integrated circuits. These circuits implement the algorithms with a high degree of efficiency, modularity, and testability. The digital processor is controlled by a Digital Equipment Corporation (DEC) PDP 11 minicomputer and can be interfaced to electronic printing and/or electronic scanning de-vices. The processor has been used to process over a thousand diagnostic images.

  11. On-line structure-lossless digital mammogram image compression

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Huang, H. K.

    1996-04-01

    This paper proposes a novel on-line structure lossless compression method for digital mammograms during the film digitization process. The structure-lossless compression segments the breast and the background, compresses the former with a predictive lossless coding method and discards the latter. This compression scheme is carried out during the film digitization process and no additional time is required for the compression. Digital mammograms are compressed on-the-fly while they are created. During digitization, lines of scanned data are first acquired into a small temporary buffer in the scanner, then they are transferred to a large image buffer in an acquisition computer which is connected to the scanner. The compression process, running concurrently with the digitization process in the acquisition computer, constantly checks the image buffer and compresses any newly arrived data. Since compression is faster than digitization, data compression is completed as soon as digitization is finished. On-line compression during digitization does not increase overall digitizing time. Additionally, it reduces the mammogram image size by a factor of 3 to 9 with no loss of information. This algorithm has been implemented in a film digitizer. Statistics were obtained based on digitizing 46 mammograms at four sampling distances from 50 to 200 microns.

  12. Image processing techniques for digital orthophotoquad production

    USGS Publications Warehouse

    Hood, Joy J.; Ladner, L. J.; Champion, Richard A.

    1989-01-01

    Orthophotographs have long been recognized for their value as supplements or alternatives to standard maps. Recent trends towards digital cartography have resulted in efforts by the US Geological Survey to develop a digital orthophotoquad production system. Digital image files were created by scanning color infrared photographs on a microdensitometer. Rectification techniques were applied to remove tile and relief displacement, thereby creating digital orthophotos. Image mosaicking software was then used to join the rectified images, producing digital orthophotos in quadrangle format.

  13. Acquired immunodeficiency syndrome: Ga-67 citrate imaging

    SciTech Connect

    Woolfenden, J.M.; Carrasquillo, J.A.; Larson, S.M.; Simmons, J.T.; Masur, H.; Smith, P.D.; Shelhamer, J.H.; Ognibene, F.P.

    1987-02-01

    All gallium-67 citrate scans obtained in patients with acquired immunodeficiency syndrome (AIDS) at the Clinical Center, National Institutes of Health (Bethesda, Md.) were retrospectively analyzed and correlated with the results of bronchoscopy, chest radiography, and endoscopy. There were 164 scans of 95 patients. Twenty scans were from patients with Pneumocystis carinii pneumonia; 19 were abnormal, for a sensitivity of 95%. Ga-67 uptake tended to be less in patients receiving therapy for P. carinii pneumonia. Chest radiographs were normal at least initially in three patients with abnormal scans and P. carinii pneumonia. Unusually prominent colonic activity was associated with infection in some patients. No lesions of Kaposi sarcoma showed tracer uptake. Gallium scanning is useful for detecting P. carinii pneumonia and other opportunistic infections in patients with AIDS, but it is not useful for localizing Kaposi sarcoma.

  14. Image Acquisition and Quality in Digital Radiography.

    PubMed

    Alexander, Shannon

    2016-09-01

    Medical imaging has undergone dramatic changes and technological breakthroughs since the introduction of digital radiography. This article presents information on the development of digital radiography and types of digital radiography systems. Aspects of image quality and radiation exposure control are highlighted as well. In addition, the article includes related workplace changes and medicolegal considerations in the digital radiography environment. PMID:27601691

  15. Effects of Digitization and JPEG Compression on Land Cover Classification Using Astronaut-Acquired Orbital Photographs

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.; Webb, Edward L.; Evangelista, Arlene

    2000-01-01

    Studies that utilize astronaut-acquired orbital photographs for visual or digital classification require high-quality data to ensure accuracy. The majority of images available must be digitized from film and electronically transferred to scientific users. This study examined the effect of scanning spatial resolution (1200, 2400 pixels per inch [21.2 and 10.6 microns/pixel]), scanning density range option (Auto, Full) and compression ratio (non-lossy [TIFF], and lossy JPEG 10:1, 46:1, 83:1) on digital classification results of an orbital photograph from the NASA - Johnson Space Center archive. Qualitative results suggested that 1200 ppi was acceptable for visual interpretive uses for major land cover types. Moreover, Auto scanning density range was superior to Full density range. Quantitative assessment of the processing steps indicated that, while 2400 ppi scanning spatial resolution resulted in more classified polygons as well as a substantially greater proportion of polygons < 0.2 ha, overall agreement between 1200 ppi and 2400 ppi was quite high. JPEG compression up to approximately 46:1 also did not appear to have a major impact on quantitative classification characteristics. We conclude that both 1200 and 2400 ppi scanning resolutions are acceptable options for this level of land cover classification, as well as a compression ratio at or below approximately 46:1. Auto range density should always be used during scanning because it acquires more of the information from the film. The particular combination of scanning spatial resolution and compression level will require a case-by-case decision and will depend upon memory capabilities, analytical objectives and the spatial properties of the objects in the image.

  16. Nanophotonic filters for digital imaging

    NASA Astrophysics Data System (ADS)

    Walls, Kirsty

    There has been an increasing demand for low cost, portable CMOS image sensors because of increased integration, and new applications in the automotive, mobile communication and medical industries, amongst others. Colour reproduction remains imperfect in conventional digital image sensors, due to the limitations of the dye-based filters. Further improvement is required if the full potential of digital imaging is to be realised. In alternative systems, where accurate colour reproduction is a priority, existing equipment is too bulky for anything but specialist use. In this work both these issues are addressed by exploiting nanophotonic techniques to create enhanced trichromatic filters, and multispectral filters, all of which can be fabricated on-chip, i.e. integrated into a conventional digital image sensor, to create compact, low cost, mass produceable imaging systems with accurate colour reproduction. The trichromatic filters are based on plasmonic structures. They exploit the excitation of surface plasmon resonances in arrays of subwavelength holes in metal films to filter light. The currently-known analytical expressions are inadequate for optimising all relevant parameters of a plasmonic structure. In order to obtain arbitrary filter characteristics, an automated design procedure was developed that integrated a genetic algorithm and 3D finite-difference time-domain tool. The optimisation procedure's efficacy is demonstrated by designing a set of plasmonic filters that replicate the CIE (1931) colour matching functions, which themselves mimic the human eye's daytime colour response.

  17. Digital Images on the DIME

    NASA Technical Reports Server (NTRS)

    2003-01-01

    With NASA on its side, Positive Systems, Inc., of Whitefish, Montana, is veering away from the industry standards defined for producing and processing remotely sensed images. A top developer of imaging products for geographic information system (GIS) and computer-aided design (CAD) applications, Positive Systems is bucking traditional imaging concepts with a cost-effective and time-saving software tool called Digital Images Made Easy (DIME(trademark)). Like piecing a jigsaw puzzle together, DIME can integrate a series of raw aerial or satellite snapshots into a single, seamless panoramic image, known as a 'mosaic.' The 'mosaicked' images serve as useful backdrops to GIS maps - which typically consist of line drawings called 'vectors' - by allowing users to view a multidimensional map that provides substantially more geographic information.

  18. Digital imaging and fabrication.

    PubMed

    Zandparsa, Roya

    2014-01-01

    Bioceramics have been adopted in dental restorations for implants, bridges, inlays, onlays, and all-ceramic crowns. Dental bioceramics include glass ceramics, reinforced porcelains, zirconias, aluminas, fiber-reinforced ceramic composites, and multilayered ceramic structures. The process of additive manufacturing is ideally suited to dentistry. Models are designed using data from a computed tomography scan or magnetic resonance imaging. Since its development in 2001, direct ceramic machining of presintered yttria tetragonal zirconia polycrystal has become increasingly popular in dentistry. There are wide variety commercially available cements for luting all-ceramic restorations. However, resin cements have lower solubility and better aesthetic characteristics. PMID:24286650

  19. Digital imaging and fabrication.

    PubMed

    Zandparsa, Roya

    2014-01-01

    Bioceramics have been adopted in dental restorations for implants, bridges, inlays, onlays, and all-ceramic crowns. Dental bioceramics include glass ceramics, reinforced porcelains, zirconias, aluminas, fiber-reinforced ceramic composites, and multilayered ceramic structures. The process of additive manufacturing is ideally suited to dentistry. Models are designed using data from a computed tomography scan or magnetic resonance imaging. Since its development in 2001, direct ceramic machining of presintered yttria tetragonal zirconia polycrystal has become increasingly popular in dentistry. There are wide variety commercially available cements for luting all-ceramic restorations. However, resin cements have lower solubility and better aesthetic characteristics.

  20. Digital diagnosis of medical images

    NASA Astrophysics Data System (ADS)

    Heinonen, Tomi; Kuismin, Raimo; Jormalainen, Raimo; Dastidar, Prasun; Frey, Harry; Eskola, Hannu

    2001-08-01

    The popularity of digital imaging devices and PACS installations has increased during the last years. Still, images are analyzed and diagnosed using conventional techniques. Our research group begun to study the requirements for digital image diagnostic methods to be applied together with PACS systems. The research was focused on various image analysis procedures (e.g., segmentation, volumetry, 3D visualization, image fusion, anatomic atlas, etc.) that could be useful in medical diagnosis. We have developed Image Analysis software (www.medimag.net) to enable several image-processing applications in medical diagnosis, such as volumetry, multimodal visualization, and 3D visualizations. We have also developed a commercial scalable image archive system (ActaServer, supports DICOM) based on component technology (www.acta.fi), and several telemedicine applications. All the software and systems operate in NT environment and are in clinical use in several hospitals. The analysis software have been applied in clinical work and utilized in numerous patient cases (500 patients). This method has been used in the diagnosis, therapy and follow-up in various diseases of the central nervous system (CNS), respiratory system (RS) and human reproductive system (HRS). In many of these diseases e.g. Systemic Lupus Erythematosus (CNS), nasal airways diseases (RS) and ovarian tumors (HRS), these methods have been used for the first time in clinical work. According to our results, digital diagnosis improves diagnostic capabilities, and together with PACS installations it will become standard tool during the next decade by enabling more accurate diagnosis and patient follow-up.

  1. Optical-digital hybrid image search system in cloud environment

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Kodate, Kashiko; Watanabe, Eriko

    2016-09-01

    To improve the versatility and usability of optical correlators, we developed an optical-digital hybrid image search system consisting of digital servers and an optical correlator that can be used to perform image searches in the cloud environment via a web browser. This hybrid system employs a simple method to obtain correlation signals and has a distributed network design. The correlation signals are acquired by using an encoder timing signal generated by a rotating disk, and the distributed network design facilitates the replacement and combination of the digital correlation server and the optical correlator.

  2. Optical–digital hybrid image search system in cloud environment

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Kodate, Kashiko; Watanabe, Eriko

    2016-09-01

    To improve the versatility and usability of optical correlators, we developed an optical–digital hybrid image search system consisting of digital servers and an optical correlator that can be used to perform image searches in the cloud environment via a web browser. This hybrid system employs a simple method to obtain correlation signals and has a distributed network design. The correlation signals are acquired by using an encoder timing signal generated by a rotating disk, and the distributed network design facilitates the replacement and combination of the digital correlation server and the optical correlator.

  3. Digital Images and Human Vision

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Null, Cynthia H. (Technical Monitor)

    1997-01-01

    Processing of digital images destined for visual consumption raises many interesting questions regarding human visual sensitivity. This talk will survey some of these questions, including some that have been answered and some that have not. There will be an emphasis upon visual masking, and a distinction will be drawn between masking due to contrast gain control processes, and due to processes such as hypothesis testing, pattern recognition, and visual search.

  4. Digital image-based titrations.

    PubMed

    Gaiao, Edvaldo da Nobrega; Martins, Valdomiro Lacerda; Lyra, Wellington da Silva; de Almeida, Luciano Farias; da Silva, Edvan Cirino; Araújo, Mário César Ugulino

    2006-06-16

    The exploitation of digital images obtained from a CCD camera (WebCam) as a novel instrumental detection technique for titration is proposed for the first time. Named of digital image-based (DIB) titration, it also requires, as a traditional titration (for example, spectrophotometric, potentiometric, conductimetric), a discontinuity in titration curves where there is an end point, which is associated to the chemical equivalence condition. The monitored signal in the DIB titration is a RGB-based value that is calculated, for each digital image, by using a proposed procedure based on the red, green, and blue colour system. The DIB titration was applied to determine HCl and H3PO4 in aqueous solutions and total alkalinity in mineral and tap waters. Its results were compared to the spectrophotometric (SPEC) titration and, by applying the paired t-test, no statistic difference between the results of both methods was verified at the 95% confidence level. Identical standard deviations were obtained by both titrations in the determinations of HCl and H3PO4, with a slightly better precision for DIB titration in the determinations of total alkalinity. The DIB titration shows to be an efficient and promising tool for quantitative chemical analysis and, as it employs an inexpensive device (WebCam) as analytical detector, it offers an economically viable alternative to titrations that need instrumental detection.

  5. Digital image film generation: from the photoscientist's perspective

    USGS Publications Warehouse

    Boyd, John E.

    1982-01-01

    The technical sophistication of photoelectronic transducers, integrated circuits, and laser-beam film recorders has made digital imagery an alternative to traditional analog imagery for remote sensing. Because a digital image is stored in discrete digital values, image enhancement is possible before the data are converted to a photographic image. To create a special film-reproduction curve - which can simulate any desired gamma, relative film speed, and toe/shoulder response - the digital-to-analog transfer function of the film recorder is uniquely defined and implemented by a lookup table in the film recorder. Because the image data are acquired in spectral bands, false-color composites also can be given special characteristics by selecting a reproduction curve tailored for each band.

  6. Imaging spectroscopy with digital micromirrors

    NASA Astrophysics Data System (ADS)

    Kearney, Kevin J.; Corio, Mark A.; Ninkov, Zoran

    2000-05-01

    The availability of optical MEMS (Micro-Electro-Mechanical Systems) is promising to revolutionize optical instrument design. We are developing a multiobject imaging spectrometer based on a commercially available optical MEMS--the Texas Instrument's Digital Micromirror Device (DMD)TM. The micromirror array is laced at an image plane of an optical system, and is used as a spatial light modulator to redirect portions of the image into the spectrograph. The programmability of the micromirror array allows the creation of arbitrary `slit' patterns as input to the spectrograph. In addition, by controlling the dwell time of each micromirror individually, it is possible to adaptively extend the dynamic range of the spectral imaging system.

  7. Comparison of analog and digital transceiver systems for MR imaging.

    PubMed

    Hashimoto, Seitaro; Kose, Katsumi; Haishi, Tomoyuki

    2014-01-01

    We critically evaluated analog and digital transceivers for magnetic resonance (MR) imaging systems under identical experimental conditions to identify and compare their advantages and disadvantages. MR imaging experiments were performed using a 4.74-tesla vertical-bore superconducting magnet and a high sensitivity gradient coil probe. We acquired 3-dimensional spin echo images of a kumquat with and without using a gain-stepping scan technique to extend the dynamic range of the receiver systems. The acquired MR images clearly demonstrated nearly identical image quality for both transceiver systems, but DC and ghosting artifacts were obtained for the analog transceiver system. We therefore concluded that digital transceivers have several advantages over the analog transceivers.

  8. Comparison of analog and digital transceiver systems for MR imaging.

    PubMed

    Hashimoto, Seitaro; Kose, Katsumi; Haishi, Tomoyuki

    2014-01-01

    We critically evaluated analog and digital transceivers for magnetic resonance (MR) imaging systems under identical experimental conditions to identify and compare their advantages and disadvantages. MR imaging experiments were performed using a 4.74-tesla vertical-bore superconducting magnet and a high sensitivity gradient coil probe. We acquired 3-dimensional spin echo images of a kumquat with and without using a gain-stepping scan technique to extend the dynamic range of the receiver systems. The acquired MR images clearly demonstrated nearly identical image quality for both transceiver systems, but DC and ghosting artifacts were obtained for the analog transceiver system. We therefore concluded that digital transceivers have several advantages over the analog transceivers. PMID:25167877

  9. Digital image transformation and rectification of spacecraft and radar images

    NASA Technical Reports Server (NTRS)

    Wu, S. S. C.

    1985-01-01

    The application of digital processing techniques to spacecraft television pictures and radar images is discussed. The use of digital rectification to produce contour maps from spacecraft pictures is described; images with azimuth and elevation angles are converted into point-perspective frame pictures. The digital correction of the slant angle of radar images to ground scale is examined. The development of orthophoto and stereoscopic shaded relief maps from digital terrain and digital image data is analyzed. Digital image transformations and rectifications are utilized on Viking Orbiter and Lander pictures of Mars.

  10. Integrating patient digital photographs with medical imaging examinations.

    PubMed

    Ramamurthy, Senthil; Bhatti, Pamela; Arepalli, Chesnal D; Salama, Mohamed; Provenzale, James M; Tridandapani, Srini

    2013-10-01

    We introduce the concept, benefits, and general architecture for acquiring, storing, and displaying digital photographs along with medical imaging examinations. We also discuss a specific implementation built around an Android-based system for simultaneously acquiring digital photographs along with portable radiographs. By an innovative application of radiofrequency identification technology to radiographic cassettes, the system is able to maintain a tight relationship between these photographs and the radiographs within the picture archiving and communications system (PACS) environment. We provide a cost analysis demonstrating the economic feasibility of this technology. Since our architecture naturally integrates with patient identification methods, we also address patient privacy issues.

  11. Detecting Copy Move Forgery In Digital Images

    NASA Astrophysics Data System (ADS)

    Gupta, Ashima; Saxena, Nisheeth; Vasistha, S. K.

    2012-03-01

    In today's world several image manipulation software's are available. Manipulation of digital images has become a serious problem nowadays. There are many areas like medical imaging, digital forensics, journalism, scientific publications, etc, where image forgery can be done very easily. To determine whether a digital image is original or doctored is a big challenge. To find the marks of tampering in a digital image is a challenging task. The detection methods can be very useful in image forensics which can be used as a proof for the authenticity of a digital image. In this paper we propose the method to detect region duplication forgery by dividing the image into overlapping block and then perform searching to find out the duplicated region in the image.

  12. Digital processing of radiographic images

    NASA Technical Reports Server (NTRS)

    Bond, A. D.; Ramapriyan, H. K.

    1973-01-01

    Some techniques are presented and the software documentation for the digital enhancement of radiographs. Both image handling and image processing operations are considered. The image handling operations dealt with are: (1) conversion of format of data from packed to unpacked and vice versa; (2) automatic extraction of image data arrays; (3) transposition and 90 deg rotations of large data arrays; (4) translation of data arrays for registration; and (5) reduction of the dimensions of data arrays by integral factors. Both the frequency and the spatial domain approaches are presented for the design and implementation of the image processing operation. It is shown that spatial domain recursive implementation of filters is much faster than nonrecursive implementations using fast fourier transforms (FFT) for the cases of interest in this work. The recursive implementation of a class of matched filters for enhancing image signal to noise ratio is described. Test patterns are used to illustrate the filtering operations. The application of the techniques to radiographic images of metallic structures is demonstrated through several examples.

  13. A digital frame of reference for viewing digital images.

    PubMed

    Brettle, D S

    2001-01-01

    Digital imaging is becoming widespread in diagnostic radiology. Most diagnostic digital images do not relate explicitly to the physical processes involved in their generation but are, in essence, a "pseudo" image generated from digital data using pre- and post-processing. Without knowledge of how the image was generated, there is a potential to misinterpret the image data. A new design of digitally generated graphic is presented that is intended to help maintain the frame of reference when viewing digitally processed images. The intention is that the digital frame of reference (DFOR) be included with all digitally processed images and be processed using the same factors as were used on the image. An unprocessed DFOR can then be displayed adjacent to the processed DFOR to re-introduce a frame of reference and to clearly illustrate the effect of any processes that have been applied to the image. This would allow the viewer to perceive any artefacts that may have been introduced into the image by the processing. This is particularly important where the image requires interpretation by the viewer, as in medical diagnosis. This paper presents a grey scale version of the DFOR that is suitable for applications such as medical imaging. The DFOR includes: grey scale from 0 to the maximum bit depth in 0%, 30%, 70% and 100% steps on a 50% background; the full frequency range from 0 to the Nyquist frequency; high, medium and low contrast boundaries; and linear/curvilinear features. The same method could be extended to any other digital image system and could be easily modified to include colour.

  14. Mars Digital Image Mosaic Globe

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The photomosaic that forms the base for this globe was created by merging two global digital image models (DIM's) of Mars-a medium-resolution monochrome mosaic processed to emphasize topographic features and a lower resolution color mosaic emphasizing color and albedo variations.

    The medium-resolution (1/256 or roughly 231 m/pixel) monochromatic image model was constructed from about 6,000 images having resolutions of 150-350 m/pixel and oblique illumination (Sun 20 o -45 o above the horizon). Radiometric processing was intended to suppress or remove the effects of albedo variations through the use of a high-pass divide filter, followed by photometric normalization so that the contrast of a given topographic slope would be approximately the same in all images.

    The global color mosaic was assembled at 1/64 or roughly 864 m/pixel from about 1,000 red- and green-filter images having 500-1,000 m/pixel resolution. These images were first mosaiced in groups, each taken on a single orbit of the Viking spacecraft. The orbit mosaics were then processed to remove spatially and temporally varying atmospheric haze in the overlap regions. After haze removal, the per-orbit mosaics were photometrically normalized to equalize the contrast of albedo features and mosaiced together with cosmetic seam removal. The medium-resolution DIM was used for geometric control of this color mosaic. A green-filter image was synthesized by weighted averaging of the red- and violet-filter mosaics. Finally, the product seen here was obtained by multiplying each color image by the medium-resolution monochrome image. The color balance selected for images in this map series was designed to be close to natural color for brighter, redder regions, such as Arabia Terra and the Tharsis region, but the data have been stretched so that the relatively dark regions appear darker and less red than they actually are.

    The images are presented in a projection that portrays the entire surface of Mars in a

  15. Interactive digital image manipulation system

    NASA Technical Reports Server (NTRS)

    Henze, J.; Dezur, R.

    1975-01-01

    The system is designed for manipulation, analysis, interpretation, and processing of a wide variety of image data. LANDSAT (ERTS) and other data in digital form can be input directly into the system. Photographic prints and transparencies are first converted to digital form with an on-line high-resolution microdensitometer. The system is implemented on a Hewlett-Packard 3000 computer with 128 K bytes of core memory and a 47.5 megabyte disk. It includes a true color display monitor, with processing memories, graphics overlays, and a movable cursor. Image data formats are flexible so that there is no restriction to a given set of remote sensors. Conversion between data types is available to provide a basis for comparison of the various data. Multispectral data is fully supported, and there is no restriction on the number of dimensions. In this way multispectral data collected at more than one point in time may simply be treated as a data collected with twice (three times, etc.) the number of sensors. There are various libraries of functions available to the user: processing functions, display functions, system functions, and earth resources applications functions.

  16. Digital Image Compression Using Artificial Neural Networks

    NASA Technical Reports Server (NTRS)

    Serra-Ricart, M.; Garrido, L.; Gaitan, V.; Aloy, A.

    1993-01-01

    The problem of storing, transmitting, and manipulating digital images is considered. Because of the file sizes involved, large amounts of digitized image information are becoming common in modern projects. Our goal is to described an image compression transform coder based on artificial neural networks techniques (NNCTC). A comparison of the compression results obtained from digital astronomical images by the NNCTC and the method used in the compression of the digitized sky survey from the Space Telescope Science Institute based on the H-transform is performed in order to assess the reliability of the NNCTC.

  17. Digital x-ray imager

    SciTech Connect

    1998-06-18

    The global objective of this cooperation was to lower the cost and improve the quality of breast health care in the United States. We planned to achieve it by designing a very high performance digital radiography unit for breast surgical specimen radiography in the operating room. These technical goals needed to be achieved at reasonable manufacturing costs to enable MedOptics to achieve high market penetration at a profit. Responsibility for overall project execution rested with MedOptics. MedOptics fabricated and demonstrated hardware, and selected components and handled the overall integration. After completion of this CRADA, MedOptics worked with collaborators to demonstrate clinical performance and utility. Finally, the company marketed the device. LLNL convened a multi-directorate expert panel for an intensive review of MedOptics point design. A written brief of panel conclusions and recommendations was prepared. In addition, LLNL was responsible for: computationally simulating the effects of varying source voltage and filtering (predicting the required dynamic range for the detector); evaluating CsI:Tl, CdWO4 and scintillating glass as image converters; recommending image enhancement algorithms. The LLNL modeling results guided the design and experimental elements of the project. The Laboratory's unique array of sources and detectors was employed to resolve specific technical questions. Our image processing expertise was applied to the selection of enhancement tools for image display.

  18. Digital image transformation and rectification of spacecraft and radar images

    USGS Publications Warehouse

    Wu, S.S.C.

    1985-01-01

    Digital image transformation and rectification can be described in three categories: (1) digital rectification of spacecraft pictures on workable stereoplotters; (2) digital correction of radar image geometry; and (3) digital reconstruction of shaded relief maps and perspective views including stereograms. Digital rectification can make high-oblique pictures workable on stereoplotters that would otherwise not accommodate such extreme tilt angles. It also enables panoramic line-scan geometry to be used to compile contour maps with photogrammetric plotters. Rectifications were digitally processed on both Viking Orbiter and Lander pictures of Mars as well as radar images taken by various radar systems. By merging digital terrain data with image data, perspective and three-dimensional views of Olympus Mons and Tithonium Chasma, also of Mars, are reconstructed through digital image processing. ?? 1985.

  19. Authenticity and integrity of digital mammography images.

    PubMed

    Zhou, X Q; Huang, H K; Lou, S L

    2001-08-01

    Data security becomes more and more important in telemammography which uses a public high-speed wide area network connecting the examination site with the mammography expert center. Generally, security is characterized in terms of privacy, authenticity and integrity of digital data. Privacy is a network access issue and is not considered in this paper. We present a method, authenticity and integrity of digital mammography, here which can meet the requirements of authenticity and integrity for mammography image (IM) transmission. The authenticity and integrity for mammography (AIDM) consists of the following four modules. 1) Image preprocessing: To segment breast pixels from background and extract patient information from digital imaging and communication in medicine (DICOM) image header. 2) Image hashing: To compute an image hash value of the mammogram using the MD5 hash algorithm. 3) Data encryption: To produce a digital envelope containing the encrypted image hash value (digital signature) and corresponding patient information. 4) Data embedding: To embed the digital envelope into the image. This is done by replacing the least significant bit of a random pixel of the mammogram by one bit of the digital envelope bit stream and repeating for all bits in the bit stream. Experiments with digital IMs demonstrate the following. 1) In the expert center, only the user who knows the private key can open the digital envelope and read the patient information data and the digital signature of the mammogram transmitted from the examination site. 2) Data integrity can be verified by matching the image hash value decrypted from the digital signature with that computed from the transmitted image. 3) No visual quality degradation is detected in the embedded image compared with the original. Our preliminary results demonstrate that AIDM is an effective method for image authenticity and integrity in telemammography application.

  20. In-line digital holographic imaging in volume holographic microscopy.

    PubMed

    Zhai, Xiaomin; Lin, Wei-Tang; Chen, Hsi-Hsun; Wang, Po-Hao; Yeh, Li-Hao; Tsai, Jui-Chang; Singh, Vijay Raj; Luo, Yuan

    2015-12-01

    A dual-plane in-line digital holographic imaging method incorporating volume holographic microscopy (VHM) is presented to reconstruct objects in a single shot while eliminating zero-order and twin-image diffracted waves. The proposed imaging method is configured such that information from different axial planes is acquired simultaneously using multiplexed volume holographic imaging gratings, as used in VHM, and recorded as in-line holograms where the corresponding reference beams are generated in the fashion of Gabor's in-line holography. Unlike conventional VHM, which can take axial intensity information only at focal depths, the proposed method digitally reconstructs objects at any axial position. Further, we demonstrate the proposed imaging technique's ability to effectively eliminate zero-order and twin images for single-shot three-dimensional object reconstruction. PMID:26625046

  1. Evaluation of outliers in acquired brain MR images

    NASA Astrophysics Data System (ADS)

    Moldovanu, S.; (Vişan Pungǎ, M.; Moraru, L.

    2015-01-01

    Pre-processing is an important stage in the analysis of magnetic resonance images (MRI), because the effect of specific image artefacts, such as intensity inhomogeneity, noise and low contrast can adversely affect the quantitative image analysis. The image histogram is a useful tool in the analysis of MR images given that it allows a close relationship with important image features such as contrast and noise. The noise and variable contrast are elements that locally modify the quality of images. The key issue of this study derives from the fact that the spatial histogram can contain outliers indicating corrupted image information through the disorder of the bins. These aberrant errors should be excluded from the studied data sets. Here, the outliers are evaluated by using rigorous methods based on the probability theory and Chauvenet (CC), Grubbs (GC) and Peirce's (PC) criteria. In order to check the quality of the MR images, the Minkowsky (MD), Euclidean (ED) and cosine (CD) distance functions were used. They act as similarity scores between the histogram of the acquired MRI and the processed image. This analysis is necessary because, sometimes, the distance function exceeds the co-domain because of the outliers. In this paper, 32 MRIs are tested and the outliers are removed so that the distance functions generate uncorrupted and real values.

  2. Digital Imaging: An Adobe Photoshop Course

    ERIC Educational Resources Information Center

    Cobb, Kristine

    2007-01-01

    This article introduces digital imaging, an Adobe Photoshop course at Shrewsbury High School in Shrewsbury, Massachusetts. Students are able to earn art credits to graduate by successfully completing the course. Digital imaging must cover art criteria as well as technical skills. The course begins with tutorials created by the instructor and other…

  3. Ethical Implications of Digital Imaging in Photojournalism.

    ERIC Educational Resources Information Center

    Terry, Danal; Lasorsa, Dominic L.

    Arguing that the news media are about to adopt digital imaging systems that will have far-reaching implications for the practice of journalism, this paper discusses how the news media is expected to adopt the new technology and explains why the marriage of journalism and digital imaging will create ethical issues with respect to photo manipulation…

  4. An approach of DSM generation from multi-view images acquired by UAVs

    NASA Astrophysics Data System (ADS)

    Hu, DaTian; Ai, Mingyao; Hu, Qingwu; Li, Jiayuan

    2016-03-01

    In the past few years, for its lower-cost, safer and high-resolution images, unmanned aerial vehicles (UAVs) demonstrated great potential for photogrammetric measurements in numerous application fields. Nevertheless, these images are often affected by large rotation, big viewpoint change as well as small overlaps, in which case traditional procedure are not able to orientate images or generate reliable Digital Generation Models (DSM). This paper introduces the whole procedure of the DSM generation, which comprehensively utilizes advantage of both computer vision and multi-image matching algorithms in extracting points and generating a dense DSM. Experiment shows that, based on this procedure, it can quickly extract points from the high-resolution images acquired by UAVs with high location accuracy.

  5. Adaptive SVD-Based Digital Image Watermarking

    NASA Astrophysics Data System (ADS)

    Shirvanian, Maliheh; Torkamani Azar, Farah

    Digital data utilization along with the increase popularity of the Internet has facilitated information sharing and distribution. However, such applications have also raised concern about copyright issues and unauthorized modification and distribution of digital data. Digital watermarking techniques which are proposed to solve these problems hide some information in digital media and extract it whenever needed to indicate the data owner. In this paper a new method of image watermarking based on singular value decomposition (SVD) of images is proposed which considers human visual system prior to embedding watermark by segmenting the original image into several blocks of different sizes, with more density in the edges of the image. In this way the original image quality is preserved in the watermarked image. Additional advantages of the proposed technique are large capacity of watermark embedding and robustness of the method against different types of image manipulation techniques.

  6. Image rejects in general direct digital radiography

    PubMed Central

    Rosanowsky, Tine Blomberg; Jensen, Camilla; Wah, Kenneth Hong Ching

    2015-01-01

    Background The number of rejected images is an indicator of image quality and unnecessary imaging at a radiology department. Image reject analysis was frequent in the film era, but comparably few and small studies have been published after converting to digital radiography. One reason may be a belief that rejects have been eliminated with digitalization. Purpose To measure the extension of deleted images in direct digital radiography (DR), in order to assess the rates of rejects and unnecessary imaging and to analyze reasons for deletions, in order to improve the radiological services. Material and Methods All exposed images at two direct digital laboratories at a hospital in Norway were reviewed in January 2014. Type of examination, number of exposed images, and number of deleted images were registered. Each deleted image was analyzed separately and the reason for deleting the image was recorded. Results Out of 5417 exposed images, 596 were deleted, giving a deletion rate of 11%. A total of 51.3% were deleted due to positioning errors and 31.0% due to error in centering. The examinations with the highest percentage of deleted images were the knee, hip, and ankle, 20.6%, 18.5%, and 13.8% respectively. Conclusion The reject rate is at least as high as the deletion rate and is comparable with previous film-based imaging systems. The reasons for rejection are quite different in digital systems. This falsifies the hypothesis that digitalization would eliminates rejects. A deleted image does not contribute to diagnostics, and therefore is an unnecessary image. Hence, the high rates of deleted images have implications for management, training, education, as well as for quality. PMID:26500784

  7. Coastal Digital Surface Model on Low Contrast Images

    NASA Astrophysics Data System (ADS)

    Rosu, A.-M.; Assenbaum, M.; De la Torre, Y.; Pierrot-Deseilligny, M.

    2015-08-01

    Coastal sandy environments are extremely dynamic and require regular monitoring that can easily be achieved by using an unmanned aerial system (UAS) including a drone and a photo camera. The acquired images have low contrast and homogeneous texture. Using these images and with very few, if any, ground control points (GCPs), it is difficult to obtain a digital surface model (DSM) by classical correlation and automatic interest points determination approach. A possible response to this problem is to work with enhanced, contrast filtered images. To achieve this, we use and tune the free open-source software MicMac.

  8. Parallel Analog-to-Digital Image Processor

    NASA Technical Reports Server (NTRS)

    Lokerson, D. C.

    1987-01-01

    Proposed integrated-circuit network of many identical units convert analog outputs of imaging arrays of x-ray or infrared detectors to digital outputs. Converter located near imaging detectors, within cryogenic detector package. Because converter output digital, lends itself well to multiplexing and to postprocessing for correction of gain and offset errors peculiar to each picture element and its sampling and conversion circuits. Analog-to-digital image processor is massively parallel system for processing data from array of photodetectors. System built as compact integrated circuit located near local plane. Buffer amplifier for each picture element has different offset.

  9. Digital image registration method based upon binary boundary maps

    NASA Technical Reports Server (NTRS)

    Jayroe, R. R., Jr.; Andrus, J. F.; Campbell, C. W.

    1974-01-01

    A relatively fast method is presented for matching or registering the digital data of imagery from the same ground scene acquired at different times, or from different multispectral images, sensors, or both. It is assumed that the digital images can be registed by using translations and rotations only, that the images are of the same scale, and that little or no distortion exists between images. It is further assumed that by working with several local areas of the image, the rotational effects in the local areas can be neglected. Thus, by treating the misalignments of local areas as translations, it is possible to determine rotational and translational misalignments for a larger portion of the image containing the local areas. This procedure of determining the misalignment and then registering the data according to the misalignment can be repeated until the desired degree of registration is achieved. The method to be presented is based upon the use of binary boundary maps produced from the raw digital imagery rather than the raw digital data.

  10. Digital imaging technology assessment: Digital document storage project

    NASA Technical Reports Server (NTRS)

    1989-01-01

    An ongoing technical assessment and requirements definition project is examining the potential role of digital imaging technology at NASA's STI facility. The focus is on the basic components of imaging technology in today's marketplace as well as the components anticipated in the near future. Presented is a requirement specification for a prototype project, an initial examination of current image processing at the STI facility, and an initial summary of image processing projects at other sites. Operational imaging systems incorporate scanners, optical storage, high resolution monitors, processing nodes, magnetic storage, jukeboxes, specialized boards, optical character recognition gear, pixel addressable printers, communications, and complex software processes.

  11. Digital Image Distribution: A Study of Costs and Uses.

    ERIC Educational Resources Information Center

    Besser, Howard

    1999-01-01

    Describes a study that examined an experimental multi-site image distribution scheme among museums and universities in California, The Museum Educational Site Licensing Project, whose content was primarily digital images and metadata. Discusses barriers to using digital images; digital image distribution; comparing digital images to analog slide…

  12. Does image reduction affect the diagnostic accuracy of digital mammograms?

    NASA Astrophysics Data System (ADS)

    Takane, Yumi; Kawasumi, Yusuke; Horie, Tsunemitsu; Ishibashi, Tadashi

    2013-03-01

    We aimed to evaluate the influence of image reduction using a bi-cubic interpolation method on the accuracy of detection of clustered microcalcifications (MCLs) and masses on digital mammograms. Digital mammograms (n=194) of 97 subjects were selected retrospectively, comprising 47 patients with clustered MCLs or masses and 52 controls. Images were acquired in the craniocaudal view by phase-contrast mammography (PCM). Original PCM images comprised 25-μm pixels. The reduced images converted from the originals by bi-cubic interpolation were of 50-μm pixel size. Five observers independently interpreted all images, and rated their confidence concerning the presence of lesions on a continuous 0-100 scale. Receiver-operating characteristic (ROC) analysis was performed using the jackknife method and LABMRMC program. Differences in areas under the curve (AUC) values based on 95% confidence intervals were evaluated. The average AUC values for detection of masses were 0.8435 and 0.8646 for the original and reduced images, respectively. The difference between the average AUC values was not statistically significant (p=0.5855). Average AUC values for clustered MCLs detection were 0.9273 and 0.9574 for the original and reduced images, respectively. This difference was not statistically significant (p=0.1949). Detection of masses and clustered MCLs on digital mammograms was unaffected by bi-cubic interpolation image reduction.

  13. Digital Imaging and Conservation: Model Guidelines.

    ERIC Educational Resources Information Center

    Dean, John F.

    2003-01-01

    Examines the intersection of conservation and digital imaging based on guidelines at the Cornell University (Ithaca, NY) library. Discusses the digitization of artifacts; assessing the condition prior to scanning; scanning considerations, including temperature and humidity, lighting, and security; stable storage of artifacts after scanning; and…

  14. Development of standard digital images for pneumoconiosis.

    PubMed

    Lee, Won-Jeong; Choi, Byung-Soon; Kim, Sung Jin; Park, Choong-Ki; Park, Jai-Soung; Tae, Seok; Hering, Kurt Georg

    2011-11-01

    We developed the standard digital images (SDIs) to be used in the classification and recognition of pneumoconiosis. From July 3, 2006 through August 31, 2007, 531 retired male workers exposed to inorganic dust were examined by digital (DR) and analog radiography (AR) on the same day, after being approved by our institutional review board and obtaining informed consent from all participants. All images were twice classified according to the International Labour Office (ILO) 2000 guidelines with reference to ILO standard analog radiographs (SARs) by four chest radiologists. After consensus reading on 349 digital images matched with the first selected analog images, 120 digital images were selected as the SDIs that considered the distribution of pneumoconiosis findings. Images with profusion category 0/1, 1, 2, and 3 were 12, 50, 40, and 15, respectively, and a large opacity were in 43 images (A = 20, B = 22, C = 1). Among pleural abnormality, costophrenic angle obliteration, pleural plaque and thickening were in 11 (9.2%), 31 (25.8%), and 9 (7.5%) images, respectively. Twenty-one of 29 symbols were present except cp, ef, ho, id, me, pa, ra, and rp. A set of 120 SDIs had more various pneumoconiosis findings than ILO SARs that were developed from adequate methods. It can be used as digital reference images for the recognition and classification of pneumoconiosis. PMID:22065894

  15. Digital image-rectification system

    NASA Technical Reports Server (NTRS)

    Van Wie, P. H.; Stein, M.; Puccinelli, E.; Fields, B.

    1977-01-01

    System removes spatial distortions from data and brings data into conformance with Universal Transverse Mercator map projection, produces digital output products suitable for further machine processing and analysis, and fills need for geometrically corrected Landsat multispectral scanner digital data in several remote sensing application areas.

  16. Digital Image Analysis for DETCHIP® Code Determination

    PubMed Central

    Lyon, Marcus; Wilson, Mark V.; Rouhier, Kerry A.; Symonsbergen, David J.; Bastola, Kiran; Thapa, Ishwor; Holmes, Andrea E.

    2013-01-01

    DETECHIP® is a molecular sensing array used for identification of a large variety of substances. Previous methodology for the analysis of DETECHIP® used human vision to distinguish color changes induced by the presence of the analyte of interest. This paper describes several analysis techniques using digital images of DETECHIP®. Both a digital camera and flatbed desktop photo scanner were used to obtain Jpeg images. Color information within these digital images was obtained through the measurement of red-green-blue (RGB) values using software such as GIMP, Photoshop and ImageJ. Several different techniques were used to evaluate these color changes. It was determined that the flatbed scanner produced in the clearest and more reproducible images. Furthermore, codes obtained using a macro written for use within ImageJ showed improved consistency versus pervious methods. PMID:25267940

  17. DNA image cytometry in acquired immune deficiency syndrome (AIDS).

    PubMed

    Auffermann, W; Krueger, G R; Böcking, A

    1986-03-01

    In nine cases with the acquired immune deficiency syndrome (AIDS), including four stage I cases, three stage II cases and two stage III cases, DNA image cytometry was performed on Feulgen-stained lymph node imprint smears. Diploidy was found in three cases, tetraploidy in three cases and octoploidy in two cases. Aneuploid DNA distribution patterns were not seen. The lymphoid cells showed an enormously increased proliferation rate. Two cases in stage I revealed characteristic intranuclear DNA inclusions in lymphoid cells. These results indicate that DNA image cytometry may be useful as an adjunct to surgical pathology in certain cases to assist in the differential diagnosis between AIDS and benign conditions of the lymphoid system as well as between AIDS and malignant lymphomas, which usually have aneuploid DNA patterns.

  18. Digital image centering. II. [for astronomical photography

    NASA Technical Reports Server (NTRS)

    Auer, L. H.; Van Altena, W. F.

    1978-01-01

    Digital image centering algorithms were compared in a test involving microdensitometer raster scans of a refractor parallax series consisting of 22 stars on 26 plates. The highest accuracy in determining stellar image positions was provided by an algorithm which involved fitting of a symmetric Gaussian curve and a flat background to the image marginal density distributions. Algorithms involving transmission marginals instead of density marginals were found to be less accurate. The repeatability and computational efficiency of the digital image centering technique were also studied.

  19. Digital Image Representation and Access.

    ERIC Educational Resources Information Center

    Mostafa, Javed

    1994-01-01

    Reviews the literature relating to the development and application of modern imaging technology between 1987 and 1993. Highlights include image representation, including image data, compression, and image formats; and image access, including indexing and modeling, user interface design, and distributed access. (143 references) (LRW)

  20. Building a training image with Digital Outcrop Models

    NASA Astrophysics Data System (ADS)

    Pickel, A.; Frechette, J. D.; Comunian, A.; Weissmann, G. S.

    2015-12-01

    Current standard geostatistical approaches to characterizing subsurface heterogeneity may not capture realistic facies geometries and fluid flow paths. Multiple-point statistics (MPS) has shown promise in portraying complex geometries realistically; however, realizations are limited by the reliability of the model of heterogeneity upon which MPS relies, that is the Training Image (TI). Attempting to increase realism captured in TIs, a quantitative outcrop analog based approach utilizing terrestrial lidar and high-resolution, calibrated digital photography is combined with lithofacies analysis to produce TIs. Terrestrial lidar scans and high-resolution digital imagery were acquired of a Westwater Canyon Member, Morrison Formation outcrop in Ojito Wilderness, New Mexico, USA. The resulting point cloud was used to develop a cm scale mesh. Digital images of the outcrop were processed through a combination of photogrammetric techniques and manual digitizing to delineate different facies and sedimentary structures. The classified images were projected onto the high-resolution mesh creating a physically plausible Digital Outcrop Model (DOM), portions of which were used to build MPS TIs. The resulting MPS realization appears to capture realistic geometries of the deposit and empirically honors facies distributions.

  1. Digital image forensics for photographic copying

    NASA Astrophysics Data System (ADS)

    Yin, Jing; Fang, Yanmei

    2012-03-01

    Image display technology has greatly developed over the past few decades, which make it possible to recapture high-quality images from the display medium, such as a liquid crystal display(LCD) screen or a printed paper. The recaptured images are not regarded as a separate image class in the current research of digital image forensics, while the content of the recaptured images may have been tempered. In this paper, two sets of features based on the noise and the traces of double JPEG compression are proposed to identify these recaptured images. Experimental results showed that our proposed features perform well for detecting photographic copying.

  2. Digital image envelope: method and evaluation

    NASA Astrophysics Data System (ADS)

    Huang, H. K.; Cao, Fei; Zhou, Michael Z.; Mogel, Greg T.; Liu, Brent J.; Zhou, Xiaoqiang

    2003-05-01

    Health data security, characterized in terms of data privacy, authenticity, and integrity, is a vital issue when digital images and other patient information are transmitted through public networks in telehealth applications such as teleradiology. Mandates for ensuring health data security have been extensively discussed (for example The Health Insurance Portability and Accountability Act, HIPAA) and health informatics guidelines (such as the DICOM standard) are beginning to focus on issues of data continue to be published by organizing bodies in healthcare; however, there has not been a systematic method developed to ensure data security in medical imaging Because data privacy and authenticity are often managed primarily with firewall and password protection, we have focused our research and development on data integrity. We have developed a systematic method of ensuring medical image data integrity across public networks using the concept of the digital envelope. When a medical image is generated regardless of the modality, three processes are performed: the image signature is obtained, the DICOM image header is encrypted, and a digital envelope is formed by combining the signature and the encrypted header. The envelope is encrypted and embedded in the original image. This assures the security of both the image and the patient ID. The embedded image is encrypted again and transmitted across the network. The reverse process is performed at the receiving site. The result is two digital signatures, one from the original image before transmission, and second from the image after transmission. If the signatures are identical, there has been no alteration of the image. This paper concentrates in the method and evaluation of the digital image envelope.

  3. Comparison of rotation algorithms for digital images

    NASA Astrophysics Data System (ADS)

    Starovoitov, Valery V.; Samal, Dmitry

    1999-09-01

    The paper presents a comparative study of several algorithms developed for digital image rotation. No losing generality we studied gray scale images. We have tested methods preserving gray values of the original images, performing some interpolation and two procedures implemented into the Corel Photo-paint and Adobe Photoshop soft packages. By the similar way methods for rotation of color images may be evaluated also.

  4. Computer-vision-based weed identification of images acquired by 3CCD camera

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; He, Yong; Fang, Hui

    2006-09-01

    Selective application of herbicide to weeds at an earlier stage in crop growth is an important aspect of site-specific management of field crops. For approaches more adaptive in developing the on-line weed detecting application, more researchers involves in studies on image processing techniques for intensive computation and feature extraction tasks to identify the weeds from the other crops and soil background. This paper investigated the potentiality of applying the digital images acquired by the MegaPlus TM MS3100 3-CCD camera to segment the background soil from the plants in question and further recognize weeds from the crops using the Matlab script language. The image of the near-infrared waveband (center 800 nm; width 65 nm) was selected principally for segmenting soil and identifying the cottons from the thistles was achieved based on their respective relative area (pixel amount) in the whole image. The results show adequate recognition that the pixel proportion of soil, cotton leaves and thistle leaves were 78.24%(-0.20% deviation), 16.66% (+ 2.71% SD) and 4.68% (-4.19% SD). However, problems still exists by separating and allocating single plants for their clustering in the images. The information in the images acquired via the other two channels, i.e., the green and the red bands, need to be extracted to help the crop/weed discrimination. More optical specimens should be acquired for calibration and validation to establish the weed-detection model that could be effectively applied in fields.

  5. Image display device in digital TV

    DOEpatents

    Choi, Seung Jong

    2006-07-18

    Disclosed is an image display device in a digital TV that is capable of carrying out the conversion into various kinds of resolution by using single bit map data in the digital TV. The image display device includes: a data processing part for executing bit map conversion, compression, restoration and format-conversion for text data; a memory for storing the bit map data obtained according to the bit map conversion and compression in the data processing part and image data inputted from an arbitrary receiving part, the receiving part receiving one of digital image data and analog image data; an image outputting part for reading the image data from the memory; and a display processing part for mixing the image data read from the image outputting part and the bit map data converted in format from the a data processing part. Therefore, the image display device according to the present invention can convert text data in such a manner as to correspond with various resolution, carry out the compression for bit map data, thereby reducing the memory space, and support text data of an HTML format, thereby providing the image with the text data of various shapes.

  6. Photography/Digital Imaging: Parallel & Paradoxical Histories.

    ERIC Educational Resources Information Center

    Witte, Mary Stieglitz

    With the introduction of photography and photomechanical printing processes in the 19th century, the first age of machine pictures and reproductions emerged. The 20th century introduced computer image processing systems, creating a digital imaging revolution. Rather than concentrating on the adversarial aspects of the computer's influence on…

  7. Digital Image Processing in Private Industry.

    ERIC Educational Resources Information Center

    Moore, Connie

    1986-01-01

    Examines various types of private industry optical disk installations in terms of business requirements for digital image systems in five areas: records management; transaction processing; engineering/manufacturing; information distribution; and office automation. Approaches for implementing image systems are addressed as well as key success…

  8. Self-acquired patient images: the promises and the pitfalls.

    PubMed

    Damanpour, Shadi; Srivastava, Divya; Nijhawan, Rajiv I

    2016-03-01

    Self-acquired patient images, also known as selfies, are increasingly utilized in the practice of dermatology; however, research on their utility is somewhat limited. While the implementation of selfies has yet to be universally accepted, their role in triage appears to be especially useful. The potential for reducing office wait times, expediting referrals, and providing dermatologic services to patients with limited access to care is promising. In addition, as technology advances, the number of smartphone applications related to dermatology that are available to the general public has risen exponentially. With appropriate standardization, regulation, and confidentiality measures, these tools can be feasible adjuncts in clinical practice, dermatologic surgery, and teledermatology. Selfies likely will have a large role in dermatologic practice and delivery in the future. PMID:26963112

  9. Self-acquired patient images: the promises and the pitfalls.

    PubMed

    Damanpour, Shadi; Srivastava, Divya; Nijhawan, Rajiv I

    2016-03-01

    Self-acquired patient images, also known as selfies, are increasingly utilized in the practice of dermatology; however, research on their utility is somewhat limited. While the implementation of selfies has yet to be universally accepted, their role in triage appears to be especially useful. The potential for reducing office wait times, expediting referrals, and providing dermatologic services to patients with limited access to care is promising. In addition, as technology advances, the number of smartphone applications related to dermatology that are available to the general public has risen exponentially. With appropriate standardization, regulation, and confidentiality measures, these tools can be feasible adjuncts in clinical practice, dermatologic surgery, and teledermatology. Selfies likely will have a large role in dermatologic practice and delivery in the future.

  10. FBI compression standard for digitized fingerprint images

    NASA Astrophysics Data System (ADS)

    Brislawn, Christopher M.; Bradley, Jonathan N.; Onyshczak, Remigius J.; Hopper, Thomas

    1996-11-01

    The FBI has formulated national standards for digitization and compression of gray-scale fingerprint images. The compression algorithm for the digitized images is based on adaptive uniform scalar quantization of a discrete wavelet transform subband decomposition, a technique referred to as the wavelet/scalar quantization method. The algorithm produces archival-quality images at compression ratios of around 15 to 1 and will allow the current database of paper fingerprint cards to be replaced by digital imagery. A compliance testing program is also being implemented to ensure high standards of image quality and interchangeability of data between different implementations. We will review the current status of the FBI standard, including the compliance testing process and the details of the first-generation encoder.

  11. CT Image Processing Using Public Digital Networks

    PubMed Central

    Rhodes, Michael L.; Azzawi, Yu-Ming; Quinn, John F.; Glenn, William V.; Rothman, Stephen L.G.

    1984-01-01

    Nationwide commercial computer communication is now commonplace for those applications where digital dialogues are generally short and widely distributed, and where bandwidth does not exceed that of dial-up telephone lines. Image processing using such networks is prohibitive because of the large volume of data inherent to digital pictures. With a blend of increasing bandwidth and distributed processing, network image processing becomes possible. This paper examines characteristics of a digital image processing service for a nationwide network of CT scanner installations. Issues of image transmission, data compression, distributed processing, software maintenance, and interfacility communication are also discussed. Included are results that show the volume and type of processing experienced by a network of over 50 CT scanners for the last 32 months.

  12. Effect of image quality on calcification detection in digital mammography

    PubMed Central

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C.

    2012-01-01

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  13. Effect of image quality on calcification detection in digital mammography

    SciTech Connect

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C.

    2012-06-15

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  14. RF Device for Acquiring Images of the Human Body

    NASA Technical Reports Server (NTRS)

    Gaier, Todd C.; McGrath, William R.

    2010-01-01

    A safe, non-invasive method for forming images through clothing of large groups of people, in order to search for concealed weapons either made of metal or not, has been developed. A millimeter wavelength scanner designed in a unique, ring-shaped configuration can obtain a full 360 image of the body with a resolution of less than a millimeter in only a few seconds. Millimeter waves readily penetrate normal clothing, but are highly reflected by the human body and concealed objects. Millimeter wave signals are nonionizing and are harmless to human tissues when used at low power levels. The imager (see figure) consists of a thin base that supports a small-diameter vertical post about 7 ft (=2.13 m) tall. Attached to the post is a square-shaped ring 2 in. (=5 cm) wide and 3 ft (=91 cm) on a side. The ring is oriented horizontally, and is supported halfway along one side by a connection to a linear bearing on the vertical post. A planar RF circuit board is mounted to the inside of each side of the ring. Each circuit board contains an array of 30 receivers, one transmitter, and digitization electronics. Each array element has a printed-circuit patch antenna coupled to a pair of mixers by a 90 coupler. The mixers receive a reference local oscillator signal to a subharmonic of the transmitter frequency. A single local oscillator line feeds all 30 receivers on the board. The resulting MHz IF signals are amplified and carried to the edge of the board where they are demodulated and digitized. The transmitted signal is derived from the local oscillator at a frequency offset determined by a crystal oscillator. One antenna centrally located on each side of the square ring provides the source illumination power. The total transmitted power is less than 100 mW, resulting in an exposure level that is completely safe to humans. The output signals from all four circuit boards are fed via serial connection to a data processing computer. The computer processes the approximately 1-MB

  15. Quantitative analysis of digital microscope images.

    PubMed

    Wolf, David E; Samarasekera, Champika; Swedlow, Jason R

    2013-01-01

    This chapter discusses quantitative analysis of digital microscope images and presents several exercises to provide examples to explain the concept. This chapter also presents the basic concepts in quantitative analysis for imaging, but these concepts rest on a well-established foundation of signal theory and quantitative data analysis. This chapter presents several examples for understanding the imaging process as a transformation from sample to image and the limits and considerations of quantitative analysis. This chapter introduces to the concept of digitally correcting the images and also focuses on some of the more critical types of data transformation and some of the frequently encountered issues in quantization. Image processing represents a form of data processing. There are many examples of data processing such as fitting the data to a theoretical curve. In all these cases, it is critical that care is taken during all steps of transformation, processing, and quantization.

  16. Quantitative analysis of digital microscope images.

    PubMed

    Wolf, David E; Samarasekera, Champika; Swedlow, Jason R

    2013-01-01

    This chapter discusses quantitative analysis of digital microscope images and presents several exercises to provide examples to explain the concept. This chapter also presents the basic concepts in quantitative analysis for imaging, but these concepts rest on a well-established foundation of signal theory and quantitative data analysis. This chapter presents several examples for understanding the imaging process as a transformation from sample to image and the limits and considerations of quantitative analysis. This chapter introduces to the concept of digitally correcting the images and also focuses on some of the more critical types of data transformation and some of the frequently encountered issues in quantization. Image processing represents a form of data processing. There are many examples of data processing such as fitting the data to a theoretical curve. In all these cases, it is critical that care is taken during all steps of transformation, processing, and quantization. PMID:23931513

  17. Method of improving a digital image

    NASA Technical Reports Server (NTRS)

    Rahman, Zia-ur (Inventor); Jobson, Daniel J. (Inventor); Woodell, Glenn A. (Inventor)

    1999-01-01

    A method of improving a digital image is provided. The image is initially represented by digital data indexed to represent positions on a display. The digital data is indicative of an intensity value I.sub.i (x,y) for each position (x,y) in each i-th spectral band. The intensity value for each position in each i-th spectral band is adjusted to generate an adjusted intensity value for each position in each i-th spectral band in accordance with ##EQU1## where S is the number of unique spectral bands included in said digital data, W.sub.n is a weighting factor and * denotes the convolution operator. Each surround function F.sub.n (x,y) is uniquely scaled to improve an aspect of the digital image, e.g., dynamic range compression, color constancy, and lightness rendition. The adjusted intensity value for each position in each i-th spectral band is filtered with a common function and then presented to a display device. For color images, a novel color restoration step is added to give the image true-to-life color that closely matches human observation.

  18. A Digital Library of Radiology Images

    PubMed Central

    Kahn, Charles E.

    2006-01-01

    A web-based virtual library of peer-reviewed radiological images was created for use in education and clinical decision support. Images were obtained from open-access content of five online radiology journals and one e-learning web site. Figure captions were indexed by Medical Subject Heading (MeSH) codes, imaging modality, and patient age and sex. This digital library provides a new, valuable online resource. PMID:17238591

  19. A digital library of radiology images.

    PubMed

    Kahn, Charles E

    2006-01-01

    A web-based virtual library of peer-reviewed radiological images was created for use in education and clinical decision support. Images were obtained from open-access content of five online radiology journals and one e-learning web site. Figure captions were indexed by Medical Subject Heading (MeSH) codes, imaging modality, and patient age and sex. This digital library provides a new, valuable online resource.

  20. Digital image processing of vascular angiograms

    NASA Technical Reports Server (NTRS)

    Selzer, R. H.; Beckenbach, E. S.; Blankenhorn, D. H.; Crawford, D. W.; Brooks, S. H.

    1975-01-01

    The paper discusses the estimation of the degree of atherosclerosis in the human femoral artery through the use of a digital image processing system for vascular angiograms. The film digitizer uses an electronic image dissector camera to scan the angiogram and convert the recorded optical density information into a numerical format. Another processing step involves locating the vessel edges from the digital image. The computer has been programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge information and others from optical density variations within the lumen shadow. These measurements are combined into an atherosclerosis index, which is found in a post-mortem study to correlate well with both visual and chemical estimates of atherosclerotic disease.

  1. Digital deformation model for fisheye image rectification.

    PubMed

    Hou, Wenguang; Ding, Mingyue; Qin, Nannan; Lai, Xudong

    2012-09-24

    Fisheye lens can provide a wide view over 180°. It then has prominence advantages in three dimensional reconstruction and machine vision applications. However, the serious deformation in the image limits fisheye lens's usage. To overcome this obstacle, a new rectification method named DDM (Digital Deformation Model) is developed based on two dimensional perspective transformation. DDM is a type of digital grid representation of the deformation of each pixel on CCD chip which is built by interpolating the difference between the actual image coordinate and pseudo-ideal coordinate of each mark on a control panel. This method obtains the pseudo-ideal coordinate according to two dimensional perspective transformation by setting four mark's deformations on image. The main advantages are that this method does not rely on the optical principle of fisheye lens and has relatively less computation. In applications, equivalent pinhole images can be obtained after correcting fisheye lens images using DDM.

  2. Digital deformation model for fisheye image rectification.

    PubMed

    Hou, Wenguang; Ding, Mingyue; Qin, Nannan; Lai, Xudong

    2012-09-24

    Fisheye lens can provide a wide view over 180°. It then has prominence advantages in three dimensional reconstruction and machine vision applications. However, the serious deformation in the image limits fisheye lens's usage. To overcome this obstacle, a new rectification method named DDM (Digital Deformation Model) is developed based on two dimensional perspective transformation. DDM is a type of digital grid representation of the deformation of each pixel on CCD chip which is built by interpolating the difference between the actual image coordinate and pseudo-ideal coordinate of each mark on a control panel. This method obtains the pseudo-ideal coordinate according to two dimensional perspective transformation by setting four mark's deformations on image. The main advantages are that this method does not rely on the optical principle of fisheye lens and has relatively less computation. In applications, equivalent pinhole images can be obtained after correcting fisheye lens images using DDM. PMID:23037373

  3. Comparison of Image Quality Criteria between Digital Storage Phosphor Plate in Mammography and Full-Field Digital Mammography in the Detection of Breast Cancer

    PubMed Central

    Thevi Rajendran, Pushpa; Krishnapillai, Vijayalakshmi; Tamanang, Sulaiman; Kumari Chelliah, Kanaga

    2012-01-01

    Background: Digital mammography is slowly replacing screen film mammography. In digital mammography, 2 methods are available in acquiring images: digital storage phosphor plate and full-field digital mammography. The aim of this study was to compare the image quality acquired from the 2 methods of digital mammography in the detection of breast cancer. Methods: The study took place at the National Cancer Society, Kuala Lumpur, and followed 150 asymptomatic women for the duration of 1 year. Participating women gave informed consent and were exposed to 4 views from each system. Two radiologists independently evaluated the printed images based on the image quality criteria in mammography. McNemar’s test was used to compare the image quality criteria between the systems. Results: The agreement between the radiologists for the digital storage phosphor plate was к = 0.551 and for full-field digital mammography was к = 0.523. Full-field digital mammography was significantly better compared with the digital storage phosphor plate in right and left mediolateral oblique views (P < 0.05) in the detection of microcalcifications, which are early signs of breast cancer. However, both systems were comparable in all other aspects of image quality. Conclusion: Digital mammography is a useful screening tool for the detection of early breast cancer and ensures better prognosis and quality of life. PMID:22977375

  4. Image database for digital hand atlas

    NASA Astrophysics Data System (ADS)

    Cao, Fei; Huang, H. K.; Pietka, Ewa; Gilsanz, Vicente; Dey, Partha S.; Gertych, Arkadiusz; Pospiech-Kurkowska, Sywia

    2003-05-01

    Bone age assessment is a procedure frequently performed in pediatric patients to evaluate their growth disorder. A commonly used method is atlas matching by a visual comparison of a hand radiograph with a small reference set of old Greulich-Pyle atlas. We have developed a new digital hand atlas with a large set of clinically normal hand images of diverse ethnic groups. In this paper, we will present our system design and implementation of the digital atlas database to support the computer-aided atlas matching for bone age assessment. The system consists of a hand atlas image database, a computer-aided diagnostic (CAD) software module for image processing and atlas matching, and a Web user interface. Users can use a Web browser to push DICOM images, directly or indirectly from PACS, to the CAD server for a bone age assessment. Quantitative features on the examined image, which reflect the skeletal maturity, are then extracted and compared with patterns from the atlas image database to assess the bone age. The digital atlas method built on a large image database and current Internet technology provides an alternative to supplement or replace the traditional one for a quantitative, accurate and cost-effective assessment of bone age.

  5. Using Digital Imaging in Classroom and Outdoor Activities.

    ERIC Educational Resources Information Center

    Thomasson, Joseph R.

    2002-01-01

    Explains how to use digital cameras and related basic equipment during indoor and outdoor activities. Uses digital imaging in general botany class to identify unknown fungus samples. Explains how to select a digital camera and other necessary equipment. (YDS)

  6. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  7. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  8. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  9. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  10. 21 CFR 892.2030 - Medical image digitizer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical image digitizer. 892.2030 Section 892.2030...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.2030 Medical image digitizer. (a) Identification. A medical image digitizer is a device intended to convert an analog medical image into a...

  11. Fundamental concepts of digital image processing

    SciTech Connect

    Twogood, R.E.

    1983-03-01

    The field of a digital-image processing has experienced dramatic growth and increasingly widespread applicability in recent years. Fortunately, advances in computer technology have kept pace with the rapid growth in volume of image data in these and other applications. Digital image processing has become economical in many fields of research and in industrial and military applications. While each application has requirements unique from the others, all are concerned with faster, cheaper, more accurate, and more extensive computation. The trend is toward real-time and interactive operations, where the user of the system obtains preliminary results within a short enough time that the next decision can be made by the human processor without loss of concentration on the task at hand. An example of this is the obtaining of two-dimensional (2-D) computer-aided tomography (CAT) images. A medical decision might be made while the patient is still under observation rather than days later.

  12. Fundamental Concepts of Digital Image Processing

    DOE R&D Accomplishments Database

    Twogood, R. E.

    1983-03-01

    The field of a digital-image processing has experienced dramatic growth and increasingly widespread applicability in recent years. Fortunately, advances in computer technology have kept pace with the rapid growth in volume of image data in these and other applications. Digital image processing has become economical in many fields of research and in industrial and military applications. While each application has requirements unique from the others, all are concerned with faster, cheaper, more accurate, and more extensive computation. The trend is toward real-time and interactive operations, where the user of the system obtains preliminary results within a short enough time that the next decision can be made by the human processor without loss of concentration on the task at hand. An example of this is the obtaining of two-dimensional (2-D) computer-aided tomography (CAT) images. A medical decision might be made while the patient is still under observation rather than days later.

  13. A LANDSAT digital image rectification system

    NASA Technical Reports Server (NTRS)

    Vanwie, P.; Stein, M.

    1976-01-01

    DIRS is a digital image rectification system for the geometric correction of LANDSAT multispectral scanner digital image data. DIRS removes spatial distortions from the data and brings it into conformance with the Universal Transverse Mercator (UTM) map projection. Scene data in the form of landmarks are used to drive the geometric correction algorithms. Two dimensional least squares polynominal and spacecraft attitude modeling techniques for geometric mapping are provided. Entire scenes or selected quadrilaterals may be rectified. Resampling through nearest neighbor or cubic convolution at user designated intervals is available. The output products are in the form of digital tape in band interleaved, single band or CCT format in a rotated UTM projection. The system was designed and implemented on large scale IBM 360 computers.

  14. Applying robust multibit watermarks to digital images

    NASA Astrophysics Data System (ADS)

    Tsolis, Dimitrios; Nikolopoulos, Spiridon; Drossos, Lambros; Sioutas, Spyros; Papatheodorou, Theodore

    2009-05-01

    The current work is focusing on the implementation of a robust multibit watermarking algorithm for digital images, which is based on an innovative spread spectrum technique analysis. The paper presents the watermark embedding and detection algorithms, which use both wavelets and the Discrete Cosine Transform and analyzes the arising issues.

  15. Digital enhancement of flow field images

    NASA Technical Reports Server (NTRS)

    Kudlinski, Robert A.; Park, Stephen K.

    1988-01-01

    Most photographs of experimentally generated fluid flow fields have inherently poor photographic quality, specifically low contrast. Thus, there is a need to establish a process for quickly and accurately enhancing these photographs to provide improved versions for physical interpretation, analysis, and publication. A sequence of digital image processing techniques which have been demonstrated to effectively enhance such photographs is described.

  16. Measuring the Environment through Digital Images

    NASA Astrophysics Data System (ADS)

    Pickle, J.; Schloss, A. L.

    2009-12-01

    A network of sites for citizen scientists to take a consistent time sequence of digital photographs of the landscape and an Internet site (http://picturepost.unh.edu/) that efficiently stores and distributes the digital images creates a low-cost and sustainable resource for scientific environmental monitoring and formal and informal science education. Digital photographs taken from the same location and positioned in the same direction and orientation allow scientists to monitor a variety of environmental parameters, including plant health, growth, and phenology; erosion and deposition; water levels; and cloud and canopy cover. The PicturePost platform is simply an octagon placed in the center of a flat surface and secured to a post anchored in the ground or onto a building. The edges of the octagon allow positioning of the camera so the complete landscape may be photographed in less than a minute. A NASA-funded project, Digital Earth Watch (aka Measuring Vegetation Health, (http://mvh.sr.unh.edu) provides educational activities and background materials that help people learn about plants as environmental “green canaries” and about the basics of cameras and digital images. The website also provides free software to analyze digital images. Although this project has been in development for four years, it is only beginning to find partners in which the data support multiple efforts. A large part of this integration is a result of recent NASA funding, which has allowed a new website to be developed to archive and display the images. The developing collaborations and the development of the new website at the same time enhanced both efforts. Because the website could include tools/features that appealed to the collaborating groups, all participants contributed ideas facing fewer restrictions. PicturePost made from recycled plastic lumber.

  17. Digital color image analysis of core

    SciTech Connect

    Digoggio, R.; Burleigh, K. )

    1990-05-01

    Geologists often identify sands, shales, or UV-fluorescent zones by their color in photos of slabbed core or sidewalls. Similarly, they observe porosity as blue-dyed epoxy in thin sections. Of course, it is difficult to accurately quantify the amount of sand shale, fluorescence, or porosity by eye. With digital images, a computer can quantify the area of an image that is close in shade to a selected color, which is particularly useful for determining net sand or net fluorescence in thinly laminated zones. Digital color photography stores a video image as a large array of numbers (512 {times} 400 {times} 3 colors) in a computer file. With 32 intensity levels each for red, green, and blue, one can distinguish 32,768 different colors. A fluorescent streak or a shale has some natural variation in color that corresponds to hundreds of very similar shades. Thus, to process a digital image, one picks representative shades of some selected feature (e.g., fluorescence). The computer then calculates the eigen values and eigen vectors of the mean-centered covariance matrix of these representative colors. Based on these calculations, it determines which parts of the image have colors similar enough to the representative colors to be considered part of the selected feature. Their results show good agreement with independently measured thin section porosity and with specially prepared images having known amount of a given color.

  18. Applications and challenges of digital pathology and whole slide imaging.

    PubMed

    Higgins, C

    2015-07-01

    Virtual microscopy is a method for digitizing images of tissue on glass slides and using a computer to view, navigate, change magnification, focus and mark areas of interest. Virtual microscope systems (also called digital pathology or whole slide imaging systems) offer several advantages for biological scientists who use slides as part of their general, pharmaceutical, biotechnology or clinical research. The systems usually are based on one of two methodologies: area scanning or line scanning. Virtual microscope systems enable automatic sample detection, virtual-Z acquisition and creation of focal maps. Virtual slides are layered with multiple resolutions at each location, including the highest resolution needed to allow more detailed review of specific regions of interest. Scans may be acquired at 2, 10, 20, 40, 60 and 100 × or a combination of magnifications to highlight important detail. Digital microscopy starts when a slide collection is put into an automated or manual scanning system. The original slides are archived, then a server allows users to review multilayer digital images of the captured slides either by a closed network or by the internet. One challenge for adopting the technology is the lack of a universally accepted file format for virtual slides. Additional challenges include maintaining focus in an uneven sample, detecting specimens accurately, maximizing color fidelity with optimal brightness and contrast, optimizing resolution and keeping the images artifact-free. There are several manufacturers in the field and each has not only its own approach to these issues, but also its own image analysis software, which provides many options for users to enhance the speed, quality and accuracy of their process through virtual microscopy. Virtual microscope systems are widely used and are trusted to provide high quality solutions for teleconsultation, education, quality control, archiving, veterinary medicine, research and other fields.

  19. Modeling synthetic radar image from a digital terrain model

    NASA Astrophysics Data System (ADS)

    Durand, Philippe; Jaupi, Luan; Ghorbanzadeh, Dariush; Rudant, Jean Paul

    2015-03-01

    In this paper we propose to simulate SAR radar images that can be acquired by aircraft or satellite. This corresponds to a real problematic, in fact, an airborne radar data acquisition campaign, was conducted in the south east of France. We want to estimate the geometric deformations that a digital terrain model can be subjected. By extrapolation, this construction should also allow to understand the image distortion if a plane is replaced by a satellite. This manipulation allow to judge the relevance of a space mission to quantify geological and geomorphological data. The radar wave is an electromagnetic wave, they have the advantage of overcoming atmospheric conditions since more wavelength is large is better crossing the cloud layer. Therefore imaging radar provides continuous monitoring.

  20. Advanced enhancement techniques for digitized images

    NASA Astrophysics Data System (ADS)

    Tom, V. T.; Merenyi, R. C.; Carlotto, M. J.; Heller, W. G.

    Computer image enhancement of digitized X-ray and conventional photographs has been employed to reveal anomalies in aerospace hardware. Signal processing of these images included use of specially-developed filters to sharpen detail without sacrificing radiographic information, application of local contrast stretch and histogram equalization algorithms to display structure in low-contrast areas and employment of other unique digital processing methods. Edge detection, normally complicated by poor spatial resolution, limited contrast and recording media noise, was performed as a post-processing operation via a difference-of-Gaussians method and a least squares fitting procedures. In this manner, multi-image signal processing allowed for the precise measurement (to within 0.02 inches, rms) of the Inertial Upper Stage nozzle nosecap motion during a static test firing as well as identifying potential problems in the Solid Rocket Booster parachute deployment.

  1. Digital Imaging and Communications in Medicine

    NASA Astrophysics Data System (ADS)

    Onken, Michael; Eichelberg, Marco; Riesmeier, Jörg; Jensch, Peter

    Over the past 15 years Digital Imaging and Communications in Medicine (DICOM) has established itself as the international standard for medical image communication. Most medical imaging equipment uses DICOM network and media services to export image data, thus making this standard highly relevant for medical image processing. The first section of this chapter provides a basic introduction into DICOM with its more than 3,600 pages of technical documentation, followed by a section covering selected advanced topics of special interest for medical image processing. The introductory text familiarizes the reader with the standard's main concepts such as information objects and DICOM media and network services. The rendering pipeline for image display and the concept of DICOM conformance are also discussed. Specialized DICOM services such as advanced image display services that provide means for storing how an image was viewed ("Softcopy Presentation States") and how multiple images should be aligned on an output device ("Structured Display" and "Hanging Protocols") are described. We further describe DICOM's sophisticated approach ("Structured Reporting") for storing structured documents such as CAD information, which is then covered in more detail. Finally, the last section provides an insight into a newly developed DICOM service called "Application Hosting", which introduces a standardized plug-in architecture for image processing, thus permitting users to utilize cross-vendor image processing plug-ins in DICOM applications.

  2. Precision and error of three-dimensional phenotypic measures acquired from 3dMD photogrammetric images.

    PubMed

    Aldridge, Kristina; Boyadjiev, Simeon A; Capone, George T; DeLeon, Valerie B; Richtsmeier, Joan T

    2005-10-15

    The genetic basis for complex phenotypes is currently of great interest for both clinical investigators and basic scientists. In order to acquire a thorough understanding of the translation from genotype to phenotype, highly precise measures of phenotypic variation are required. New technologies, such as 3D photogrammetry are being implemented in phenotypic studies due to their ability to collect data rapidly and non-invasively. Before these systems can be broadly implemented, the error associated with data collected from images acquired using these technologies must be assessed. This study investigates the precision, error, and repeatability associated with anthropometric landmark coordinate data collected from 3D digital photogrammetric images acquired with the 3dMDface System. Precision, error due to the imaging system, error due to digitization of the images, and repeatability are assessed in a sample of children and adults (n = 15). Results show that data collected from images with the 3dMDface System are highly repeatable and precise. The average error associated with the placement of landmarks is sub-millimeter; both the error due to digitization and due to the imaging system are very low. The few measures showing a higher degree of error include those crossing the labial fissure, which are influenced by even subtle movement of the mandible. These results suggest that 3D anthropometric data collected using the 3dMDface System are highly reliable and, therefore, useful for evaluation of clinical dysmorphology and surgery, analyses of genotype-phenotype correlations, and inheritance of complex phenotypes. PMID:16158436

  3. Digital image processing: a primer for JVIR authors and readers: Part 3: Digital image editing.

    PubMed

    LaBerge, Jeanne M; Andriole, Katherine P

    2003-12-01

    This is the final installment of a three-part series on digital image processing intended to prepare authors for online submission of manuscripts. In the first two articles of the series, the fundamentals of digital image architecture were reviewed and methods of importing images to the computer desktop were described. In this article, techniques are presented for editing images in preparation for online submission. A step-by-step guide to basic editing with use of Adobe Photoshop is provided and the ethical implications of this activity are explored.

  4. Evaluation of clinical image processing algorithms used in digital mammography.

    PubMed

    Zanca, Federica; Jacobs, Jurgen; Van Ongeval, Chantal; Claus, Filip; Celis, Valerie; Geniets, Catherine; Provost, Veerle; Pauwels, Herman; Marchal, Guy; Bosmans, Hilde

    2009-03-01

    Screening is the only proven approach to reduce the mortality of breast cancer, but significant numbers of breast cancers remain undetected even when all quality assurance guidelines are implemented. With the increasing adoption of digital mammography systems, image processing may be a key factor in the imaging chain. Although to our knowledge statistically significant effects of manufacturer-recommended image processings have not been previously demonstrated, the subjective experience of our radiologists, that the apparent image quality can vary considerably between different algorithms, motivated this study. This article addresses the impact of five such algorithms on the detection of clusters of microcalcifications. A database of unprocessed (raw) images of 200 normal digital mammograms, acquired with the Siemens Novation DR, was collected retrospectively. Realistic simulated microcalcification clusters were inserted in half of the unprocessed images. All unprocessed images were subsequently processed with five manufacturer-recommended image processing algorithms (Agfa Musica 1, IMS Raffaello Mammo 1.2, Sectra Mamea AB Sigmoid, Siemens OPVIEW v2, and Siemens OPVIEW v1). Four breast imaging radiologists were asked to locate and score the clusters in each image on a five point rating scale. The free-response data were analyzed by the jackknife free-response receiver operating characteristic (JAFROC) method and, for comparison, also with the receiver operating characteristic (ROC) method. JAFROC analysis revealed highly significant differences between the image processings (F = 8.51, p < 0.0001), suggesting that image processing strongly impacts the detectability of clusters. Siemens OPVIEW2 and Siemens OPVIEW1 yielded the highest and lowest performances, respectively. ROC analysis of the data also revealed significant differences between the processing but at lower significance (F = 3.47, p = 0.0305) than JAFROC. Both statistical analysis methods revealed that the

  5. Evaluation of clinical image processing algorithms used in digital mammography.

    PubMed

    Zanca, Federica; Jacobs, Jurgen; Van Ongeval, Chantal; Claus, Filip; Celis, Valerie; Geniets, Catherine; Provost, Veerle; Pauwels, Herman; Marchal, Guy; Bosmans, Hilde

    2009-03-01

    Screening is the only proven approach to reduce the mortality of breast cancer, but significant numbers of breast cancers remain undetected even when all quality assurance guidelines are implemented. With the increasing adoption of digital mammography systems, image processing may be a key factor in the imaging chain. Although to our knowledge statistically significant effects of manufacturer-recommended image processings have not been previously demonstrated, the subjective experience of our radiologists, that the apparent image quality can vary considerably between different algorithms, motivated this study. This article addresses the impact of five such algorithms on the detection of clusters of microcalcifications. A database of unprocessed (raw) images of 200 normal digital mammograms, acquired with the Siemens Novation DR, was collected retrospectively. Realistic simulated microcalcification clusters were inserted in half of the unprocessed images. All unprocessed images were subsequently processed with five manufacturer-recommended image processing algorithms (Agfa Musica 1, IMS Raffaello Mammo 1.2, Sectra Mamea AB Sigmoid, Siemens OPVIEW v2, and Siemens OPVIEW v1). Four breast imaging radiologists were asked to locate and score the clusters in each image on a five point rating scale. The free-response data were analyzed by the jackknife free-response receiver operating characteristic (JAFROC) method and, for comparison, also with the receiver operating characteristic (ROC) method. JAFROC analysis revealed highly significant differences between the image processings (F = 8.51, p < 0.0001), suggesting that image processing strongly impacts the detectability of clusters. Siemens OPVIEW2 and Siemens OPVIEW1 yielded the highest and lowest performances, respectively. ROC analysis of the data also revealed significant differences between the processing but at lower significance (F = 3.47, p = 0.0305) than JAFROC. Both statistical analysis methods revealed that the

  6. Image Viewer using Digital Imaging and Communications in Medicine (DICOM)

    NASA Astrophysics Data System (ADS)

    Baraskar, Trupti N.

    2010-11-01

    Digital Imaging and Communications in Medicine is a standard for handling, storing, printing, and transmitting information in medical imaging. The National Electrical Manufacturers Association holds the copyright to this standard. It was developed by the DICOM Standards committee. The other image viewers cannot collectively store the image details as well as the patient's information. So the image may get separated from the details, but DICOM file format stores the patient's information and the image details. Main objective is to develop a DICOM image viewer. The image viewer will open .dcm i.e. DICOM image file and also will have additional features such as zoom in, zoom out, black and white inverter, magnifier, blur, B/W inverter, horizontal and vertical flipping, sharpening, contrast, brightness and .gif converter are incorporated.

  7. Digital Image Enhancement of Indic Historical Manuscripts

    NASA Astrophysics Data System (ADS)

    Shi, Zhixin; Setlur, Srirangaraj; Govindaraju, Venu

    Historical documents in Indic scripts can be found on a wide range of media such as paper, palm leaves, and parchment. Palm leaves are believed to be one of the earliest forms of writing media and their use as writing material has been recorded in various parts of the world including India. Ancient palm leaf manuscripts relating to religion, science, medicine, astronomy are still available for reference today due to many ongoing efforts for preservation of ancient documents by libraries and universities around the world. These manuscripts typically last a few centuries but with time the leaves degrade and the writing becomes illegible. Image processing techniques can help enhance the images of these manuscripts so as to enable readability of the written text. In this chapter, we propose methods for enhancing digital images of palm leaf and other historical manuscripts. We approximate the background of a gray-scale image using piece-wise linear and nonlinear models. Normalization algorithms are used on the color channels of the palm leaf image to obtain an enhanced gray-scale image. Experimental results show significant improvement in readability. An adaptive local connectivity map is used to try to segment lines of text from the enhanced images with the objective of facilitating techniques such as keyword spotting or partial OCR and thereby making it possible to index these documents for retrieval from a digital library.

  8. Digital Imaging and the Cognitive Revolution: A Media Challenge.

    ERIC Educational Resources Information Center

    Sartorius, Ute

    This paper discusses the role of digital technology within the cognitive revolution of the perception of images. It analyzes the traditional values placed on images as a source of cognition. These values are discussed in terms of the ethical and social issues raised by the use of digital image manipulation in so far as the digital era is falsely…

  9. Phase transfer function of digital imaging systems

    NASA Astrophysics Data System (ADS)

    Bhakta, Vikrant R.

    For the past several decades, optical engineering has relied heavily on Fourier analysis of linear systems as a valuable aid in realizing numerous imaging applications. Today, spatial frequency analysis via the optical transfer function (OTF) remains an integral tool for the design, characterization and testing of incoherent imaging systems. The magnitude of the complex OTF is known as the modulation transfer function (MTF) and its phase is given by the phase transfer function (PTF). The MTF represents the contrast reduction at each spatial frequency; whereas, the PTF represents the spatial shift of these frequencies. While the MTF has been used extensively to characterize imaging systems, the PTF has long been ignored because it was thought to have an insignificant presence and to be difficult to understand and measure. Through theoretical analysis and experimental demonstrations, this work addresses all of these issues and shows that the PTF is a valuable tool for modern-day digital imaging systems. The effects of optical aberrations on the PTF of an imaging system in the absence of aliasing have been analyzed in detail. However, for the digital imaging systems, the effect of aliasing on the overall system behavior becomes an important consideration. To this end, the effects of aliasing on the PTF of the sampled imaging system are described and its key properties are derived. The role of PTF as an essential metric in today's imaging systems necessitates practical PTF measurement techniques. Two, easy-to-implement, image-based methods for PTF measurement are described and experimentally validated. These measurement methods and the insights gained from the theoretical analysis are leveraged for several applications spanning diverse fields such as optical system characterization, computational imaging, and image processing.

  10. Digital Shaded-Relief Image of Alaska

    USGS Publications Warehouse

    Riehle, J.R.; Fleming, Michael D.; Molnia, B.F.; Dover, J.H.; Kelley, J.S.; Miller, M.L.; Nokleberg, W.J.; Plafker, George; Till, A.B.

    1997-01-01

    Introduction One of the most spectacular physiographic images of the conterminous United States, and the first to have been produced digitally, is that by Thelin and Pike (USGS I-2206, 1991). The image is remarkable for its crispness of detail and for the natural appearance of the artificial land surface. Our goal has been to produce a shaded-relief image of Alaska that has the same look and feel as the Thelin and Pike image. The Alaskan image could have been produced at the same scale as its lower 48 counterpart (1:3,500,000). But by insetting the Aleutian Islands into the Gulf of Alaska, we were able to print the Alaska map at a larger scale (1:2,500,000) and about the same physical size as the Thelin and Pike image. Benefits of the 1:2,500,000 scale are (1) greater resolution of topographic features and (2) ease of reference to the U.S. Geological Survey (USGS) (1987) Alaska Map E and the statewide geologic map (Beikman, 1980), which are both 1:2,500,000 scale. Manually drawn, shaded-relief images of Alaska's land surface have long been available (for example, Department of the Interior, 1909; Raisz, 1948). The topography depicted on these early maps is mainly schematic. Maps showing topographic contours were first available for the entire State in 1953 (USGS, 1:250,000) (J.H. Wittmann, USGS, written commun., 1996). The Alaska Map E was initially released in 1954 in both planimetric (revised in 1973 and 1987) and shaded-relief versions (revised in 1973, 1987, and 1996); topography depicted on the shaded-relief version is based on the 1:250,000-scale USGS topographic maps. Alaska Map E was later modified to include hypsometric tinting by Raven Maps and Images (1989, revised 1993) as copyrighted versions. Other shaded-relief images were produced for The National Geographic Magazine (LaGorce, 1956; 1:3,000,000) or drawn by Harrison (1970; 1:7,500,000) for The National Atlas of the United States. Recently, the State of Alaska digitally produced a shaded-relief image

  11. Validation of no-reference image quality index for the assessment of digital mammographic images

    NASA Astrophysics Data System (ADS)

    de Oliveira, Helder C. R.; Barufaldi, Bruno; Borges, Lucas R.; Gabarda, Salvador; Bakic, Predrag R.; Maidment, Andrew D. A.; Schiabel, Homero; Vieira, Marcelo A. C.

    2016-03-01

    To ensure optimal clinical performance of digital mammography, it is necessary to obtain images with high spatial resolution and low noise, keeping radiation exposure as low as possible. These requirements directly affect the interpretation of radiologists. The quality of a digital image should be assessed using objective measurements. In general, these methods measure the similarity between a degraded image and an ideal image without degradation (ground-truth), used as a reference. These methods are called Full-Reference Image Quality Assessment (FR-IQA). However, for digital mammography, an image without degradation is not available in clinical practice; thus, an objective method to assess the quality of mammograms must be performed without reference. The purpose of this study is to present a Normalized Anisotropic Quality Index (NAQI), based on the Rényi entropy in the pseudo-Wigner domain, to assess mammography images in terms of spatial resolution and noise without any reference. The method was validated using synthetic images acquired through an anthropomorphic breast software phantom, and the clinical exposures on anthropomorphic breast physical phantoms and patient's mammograms. The results reported by this noreference index follow the same behavior as other well-established full-reference metrics, e.g., the peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM). Reductions of 50% on the radiation dose in phantom images were translated as a decrease of 4dB on the PSNR, 25% on the SSIM and 33% on the NAQI, evidencing that the proposed metric is sensitive to the noise resulted from dose reduction. The clinical results showed that images reduced to 53% and 30% of the standard radiation dose reported reductions of 15% and 25% on the NAQI, respectively. Thus, this index may be used in clinical practice as an image quality indicator to improve the quality assurance programs in mammography; hence, the proposed method reduces the subjectivity

  12. [Digital thoracic radiology: devices, image processing, limits].

    PubMed

    Frija, J; de Géry, S; Lallouet, F; Guermazi, A; Zagdanski, A M; De Kerviler, E

    2001-09-01

    In a first part, the different techniques of digital thoracic radiography are described. Since computed radiography with phosphore plates are the most commercialized it is more emphasized. But the other detectors are also described, as the drum coated with selenium and the direct digital radiography with selenium detectors. The other detectors are also studied in particular indirect flat panels detectors and the system with four high resolution CCD cameras. In a second step the most important image processing are discussed: the gradation curves, the unsharp mask processing, the system MUSICA, the dynamic range compression or reduction, the soustraction with dual energy. In the last part the advantages and the drawbacks of computed thoracic radiography are emphasized. The most important are the almost constant good quality of the pictures and the possibilities of image processing.

  13. [Digital thoracic radiology: devices, image processing, limits].

    PubMed

    Frija, J; de Géry, S; Lallouet, F; Guermazi, A; Zagdanski, A M; De Kerviler, E

    2001-09-01

    In a first part, the different techniques of digital thoracic radiography are described. Since computed radiography with phosphore plates are the most commercialized it is more emphasized. But the other detectors are also described, as the drum coated with selenium and the direct digital radiography with selenium detectors. The other detectors are also studied in particular indirect flat panels detectors and the system with four high resolution CCD cameras. In a second step the most important image processing are discussed: the gradation curves, the unsharp mask processing, the system MUSICA, the dynamic range compression or reduction, the soustraction with dual energy. In the last part the advantages and the drawbacks of computed thoracic radiography are emphasized. The most important are the almost constant good quality of the pictures and the possibilities of image processing. PMID:11567193

  14. Storage and retrieval of large digital images

    DOEpatents

    Bradley, Jonathan N.

    1998-01-01

    Image compression and viewing are implemented with (1) a method for performing DWT-based compression on a large digital image with a computer system possessing a two-level system of memory and (2) a method for selectively viewing areas of the image from its compressed representation at multiple resolutions and, if desired, in a client-server environment. The compression of a large digital image I(x,y) is accomplished by first defining a plurality of discrete tile image data subsets T.sub.ij (x,y) that, upon superposition, form the complete set of image data I(x,y). A seamless wavelet-based compression process is effected on I(x,y) that is comprised of successively inputting the tiles T.sub.ij (x,y) in a selected sequence to a DWT routine, and storing the resulting DWT coefficients in a first primary memory. These coefficients are periodically compressed and transferred to a secondary memory to maintain sufficient memory in the primary memory for data processing. The sequence of DWT operations on the tiles T.sub.ij (x,y) effectively calculates a seamless DWT of I(x,y). Data retrieval consists of specifying a resolution and a region of I(x,y) for display. The subset of stored DWT coefficients corresponding to each requested scene is determined and then decompressed for input to an inverse DWT, the output of which forms the image display. The repeated process whereby image views are specified may take the form an interaction with a computer pointing device on an image display from a previous retrieval.

  15. Storage and retrieval of large digital images

    DOEpatents

    Bradley, J.N.

    1998-01-20

    Image compression and viewing are implemented with (1) a method for performing DWT-based compression on a large digital image with a computer system possessing a two-level system of memory and (2) a method for selectively viewing areas of the image from its compressed representation at multiple resolutions and, if desired, in a client-server environment. The compression of a large digital image I(x,y) is accomplished by first defining a plurality of discrete tile image data subsets T{sub ij}(x,y) that, upon superposition, form the complete set of image data I(x,y). A seamless wavelet-based compression process is effected on I(x,y) that is comprised of successively inputting the tiles T{sub ij}(x,y) in a selected sequence to a DWT routine, and storing the resulting DWT coefficients in a first primary memory. These coefficients are periodically compressed and transferred to a secondary memory to maintain sufficient memory in the primary memory for data processing. The sequence of DWT operations on the tiles T{sub ij}(x,y) effectively calculates a seamless DWT of I(x,y). Data retrieval consists of specifying a resolution and a region of I(x,y) for display. The subset of stored DWT coefficients corresponding to each requested scene is determined and then decompressed for input to an inverse DWT, the output of which forms the image display. The repeated process whereby image views are specified may take the form an interaction with a computer pointing device on an image display from a previous retrieval. 6 figs.

  16. [Whole slide imaging technology: from digitization to online applications].

    PubMed

    Ameisen, David; Le Naour, Gilles; Daniel, Christel

    2012-11-01

    As e-health becomes essential to modern care, whole slide images (virtual slides) are now an important clinical, teaching and research tool in pathology. Virtual microscopy consists of digitizing a glass slide by acquiring hundreds of tiles of regions of interest at different zoom levels and assembling them into a structured file. This gigapixel image can then be remotely viewed over a terminal, exactly the way pathologists use a microscope. In this article, we will first describe the key elements of this technology, from the acquisition, using a scanner or a motorized microscope, to the broadcasting of virtual slides through a local or distant viewer over an intranet or Internet connection. As virtual slides are now commonly used in virtual classrooms, clinical data and research databases, we will highlight the main issues regarding its uses in modern pathology. Emphasis will be made on quality assurance policies, standardization and scaling.

  17. Imaging of acquired coronary diseases: From children to adults.

    PubMed

    Dehaene, A; Jacquier, A; Falque, C; Gorincour, G; Gaubert, J Y

    2016-05-01

    Acquired coronary diseases include aneurysms, fistulae, dissections, and stenosis. Aneurysms may occur secondarily to Kawasaki disease, a childhood vasculitis, the prognosis of which depends on the coronary involvement, or they may be degenerative, infectious, inflammatory, or traumatic in origin. Fistulae develop between the coronary arterial system and a pulmonary or bronchial artery, or cardiac cavity. Dissections may occur spontaneously or may be post-traumatic. These coronary abnormalities may be found incidentally or may present as complications, infarction or rupture. The goals of this article are to understand acquired childhood and adult coronary diseases and their usual means of presentation, the ways of investigating them, and the principles of their treatment. PMID:27130480

  18. [Digital imaging and robotics in endoscopic surgery].

    PubMed

    Go, P M

    1998-05-23

    The introduction of endoscopical surgery has among other things influenced technical developments in surgery. Owing to digitalisation, major progress will be made in imaging and in the sophisticated technology sometimes called robotics. Digital storage makes the results of imaging diagnostics (e.g. the results of radiological examination) suitable for transmission via video conference systems for telediagnostic purposes. The availability of digital video technique renders possible the processing, storage and retrieval of moving images as well. During endoscopical operations use may be made of a robot arm which replaces the camera man. The arm does not grow tired and provides a stable image. The surgeon himself can operate or address the arm and it can remember fixed image positions to which it can return if ordered to do so. The next step is to carry out surgical manipulations via a robot arm. This may make operations more patient-friendly. A robot arm can also have remote control: telerobotics. At the Internet site of this journal a number of supplements to this article can be found, for instance three-dimensional (3D) illustrations (which is the purpose of the 3D spectacles enclosed with this issue) and a quiz (http:@appendix.niwi. knaw.nl).

  19. [Digital imaging and robotics in endoscopic surgery].

    PubMed

    Go, P M

    1998-05-23

    The introduction of endoscopical surgery has among other things influenced technical developments in surgery. Owing to digitalisation, major progress will be made in imaging and in the sophisticated technology sometimes called robotics. Digital storage makes the results of imaging diagnostics (e.g. the results of radiological examination) suitable for transmission via video conference systems for telediagnostic purposes. The availability of digital video technique renders possible the processing, storage and retrieval of moving images as well. During endoscopical operations use may be made of a robot arm which replaces the camera man. The arm does not grow tired and provides a stable image. The surgeon himself can operate or address the arm and it can remember fixed image positions to which it can return if ordered to do so. The next step is to carry out surgical manipulations via a robot arm. This may make operations more patient-friendly. A robot arm can also have remote control: telerobotics. At the Internet site of this journal a number of supplements to this article can be found, for instance three-dimensional (3D) illustrations (which is the purpose of the 3D spectacles enclosed with this issue) and a quiz (http:@appendix.niwi. knaw.nl). PMID:9627450

  20. APQ-102 imaging radar digital image quality study

    NASA Technical Reports Server (NTRS)

    Griffin, C. R.; Estes, J. M.

    1982-01-01

    A modified APQ-102 sidelooking radar collected synthetic aperture radar (SAR) data which was digitized and recorded on wideband magnetic tape. These tapes were then ground processed into computer compatible tapes (CCT's). The CCT's may then be processed into high resolution radar images by software on the CYBER computer.

  1. Milne "en Masse": A Case Study in Digitizing Large Image Collections

    ERIC Educational Resources Information Center

    Harkema, Craig; Avery, Cheryl

    2015-01-01

    In December 2012, the University of Saskatchewan Library's University Archives and Special Collections acquired the complete image collection of Courtney Milne, a professional photographer whose worked encompassed documentary, abstract and fine art photographs. From acquisition to digital curation, the authors identify, outline, and discuss the…

  2. Conductive resins improve charging and resolution of acquired images in electron microscopic volume imaging

    PubMed Central

    Nguyen, Huy Bang; Thai, Truc Quynh; Saitoh, Sei; Wu, Bao; Saitoh, Yurika; Shimo, Satoshi; Fujitani, Hiroshi; Otobe, Hirohide; Ohno, Nobuhiko

    2016-01-01

    Recent advances in serial block-face imaging using scanning electron microscopy (SEM) have enabled the rapid and efficient acquisition of 3-dimensional (3D) ultrastructural information from a large volume of biological specimens including brain tissues. However, volume imaging under SEM is often hampered by sample charging, and typically requires specific sample preparation to reduce charging and increase image contrast. In the present study, we introduced carbon-based conductive resins for 3D analyses of subcellular ultrastructures, using serial block-face SEM (SBF-SEM) to image samples. Conductive resins were produced by adding the carbon black filler, Ketjen black, to resins commonly used for electron microscopic observations of biological specimens. Carbon black mostly localized around tissues and did not penetrate cells, whereas the conductive resins significantly reduced the charging of samples during SBF-SEM imaging. When serial images were acquired, embedding into the conductive resins improved the resolution of images by facilitating the successful cutting of samples in SBF-SEM. These results suggest that improving the conductivities of resins with a carbon black filler is a simple and useful option for reducing charging and enhancing the resolution of images obtained for volume imaging with SEM. PMID:27020327

  3. Digital stain separation for histological images.

    PubMed

    Tadrous, P J

    2010-11-01

    It is often desirable to perform digital image analyses on sections prepared for human interpretation, e.g. nuclear chromatin texture analysis or three-dimensional reconstructions using sections requiring human delineation of structures of interest. Unfortunately such analyses are often more effective using stains with less complex contrast. Here an automated selective 'de-staining' method for digital images is presented. The method separates an image into its red, green and blue and hue, saturation and intensity components. A mask of stained tissue is prepared by automatic percentile thresholding. A single weighted inverted colour channel is then added to each of the three primary colour channels separately by an iterative algorithm that adjusts the weights to give minimum variance within the mask. The modified red, green and blue channels are then recombined. This method is automatic requiring no pre-definition of stain colours or special hardware. The method is demonstrated to 'de-stain' nuclei in haematoxylin and eosin (H&E) sections (and a separate haematoxylin image can be derived from this). An image of isolated brown reaction product is produced with immunoperoxidase preparations counterstained with haematoxylin. Furthermore trichrome (haematoxylin van Gieson, picrosirius red) and other common stains may be separated into their components with modifications of the same algorithm. Although other methods for colour separation do exist (e.g. spectral pathology and colour deconvolution) these require special apparatus or precise calibration and foreknowledge of pure dye colour spectra. The present method of digital stain separation is fully automatic with no such prerequisites.

  4. Numerical generation of digital mammograms considering imaging characteristics of an imager

    NASA Astrophysics Data System (ADS)

    Youn, Hanbean; Chul Han, Jong; Kook Cho, Min; Young Jang, Sun; Kim, Ho Kyung; Hyo Kim, Jong; Tanguay, Jesse; Cunningham, Ian A.

    2011-10-01

    Diagnosis and screening of breast cancer using digital mammography, breast tomosynthesis and cone-beam computed tomography are among the most active areas of research in diagnostic radiology. For a better design of imaging systems and the optimization of imaging technologies, numerical phantom studies are essential because of their convenience and the difficulties associated with acquiring clinical data. In this study, we have developed a procedure to numerically generate realistic digital mammograms considering the imaging characteristics of a digital mammography detector, such as resolution and noise. The procedure is composed of the generation of a voxelized breast phantom, projection and image modification. The outer shape of the breast and abnormalities are modeled with geometric functions. Soft tissue is generated by low-pass-filtered white-spectrum noise. Glandular ductal networks are generated by random angles and lengths with some restricted conditions based on anatomical information. A noise-free mammogram with the numerical voxel phantom is achieved by a simple ray-tracing method, and then modified with the known resolution and noise characteristics of an imager. This study will be helpful for the better design of mammography detectors and tomosynthesis algorithms.

  5. A new multivariate statistical model for change detection in images acquired by homogeneous and heterogeneous sensors.

    PubMed

    Prendes, Jorge; Chabert, Marie; Pascal, Frederic; Giros, Alain; Tourneret, Jean-Yves

    2015-03-01

    Remote sensing images are commonly used to monitor the earth surface evolution. This surveillance can be conducted by detecting changes between images acquired at different times and possibly by different kinds of sensors. A representative case is when an optical image of a given area is available and a new image is acquired in an emergency situation (resulting from a natural disaster for instance) by a radar satellite. In such a case, images with heterogeneous properties have to be compared for change detection. This paper proposes a new approach for similarity measurement between images acquired by heterogeneous sensors. The approach exploits the considered sensor physical properties and specially the associated measurement noise models and local joint distributions. These properties are inferred through manifold learning. The resulting similarity measure has been successfully applied to detect changes between many kinds of images, including pairs of optical images and pairs of optical-radar images.

  6. Comparison of different phantoms used in digital diagnostic imaging

    NASA Astrophysics Data System (ADS)

    Bor, Dogan; Unal, Elif; Uslu, Anil

    2015-09-01

    The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digital radiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digital images of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms.

  7. Digitally enhanced GLORIA images for petroleum exploration

    SciTech Connect

    Prindle, R.O. ); Lanz, K )

    1990-05-01

    This poster presentation graphically depicts the geological and structural information that can be derived from digitally enhanced Geological Long Range Inclined Asdic (GLORIA) sonar images. This presentation illustrates the advantages of scale enlargement as an interpreter's tool in an offshore area within the Eel River Basin, Northern California. Sonographs were produced from digital tapes originally collected for the exclusive economic zone (EEZ)-SCAN 1984 survey, which was published in the Atlas of the Western Conterminous US at a scale of 1:500,000. This scale is suitable for displaying regional offshore tectonic features but does not have the resolution required for detailed geological mapping necessary for petroleum exploration. Applications of digital enhancing techniques which utilize contrast stretching and assign false colors to wide-swath sonar imagery (approximately 40 km) with 50-m resolution enables the acquisition and interpretation of significantly more geological and structural data. This, combined with a scale enlargement to 1:100,000 and high contrast contact prints vs. the offset prints of the atlas, increases the resolution and sharpness of bathymetric features so that many more subtle features may be mapped in detail. A tectonic interpretation of these digitally enhanced GLORIA sonographs from the Eel River basin is presented, displaying anticlines, lineaments, ridge axis, pathways of sediment flow, and subtle doming. Many of these features are not present on published bathymetric maps and have not been derived from seismic data because the plan view spatial resolution is much less than that available from the GLORIA imagery.

  8. An image adaptive, wavelet-based watermarking of digital images

    NASA Astrophysics Data System (ADS)

    Agreste, Santa; Andaloro, Guido; Prestipino, Daniela; Puccio, Luigia

    2007-12-01

    In digital management, multimedia content and data can easily be used in an illegal way--being copied, modified and distributed again. Copyright protection, intellectual and material rights protection for authors, owners, buyers, distributors and the authenticity of content are crucial factors in solving an urgent and real problem. In such scenario digital watermark techniques are emerging as a valid solution. In this paper, we describe an algorithm--called WM2.0--for an invisible watermark: private, strong, wavelet-based and developed for digital images protection and authenticity. Using discrete wavelet transform (DWT) is motivated by good time-frequency features and well-matching with human visual system directives. These two combined elements are important in building an invisible and robust watermark. WM2.0 works on a dual scheme: watermark embedding and watermark detection. The watermark is embedded into high frequency DWT components of a specific sub-image and it is calculated in correlation with the image features and statistic properties. Watermark detection applies a re-synchronization between the original and watermarked image. The correlation between the watermarked DWT coefficients and the watermark signal is calculated according to the Neyman-Pearson statistic criterion. Experimentation on a large set of different images has shown to be resistant against geometric, filtering and StirMark attacks with a low rate of false alarm.

  9. Java, Image Browsing, and the NCSA Astronomy Digital Image Library

    NASA Astrophysics Data System (ADS)

    Plante, R. L.; Goscha, D.

    We review our experience, including some lessons learned, with using Java to create data browsing tools for use with the Astronomy Digital Image Library (ADIL) and related digital library projects at NCSA\\@. We give an overview of our Image Data Browser, a generalized tool under development through a collaboration with the NCSA/NASA Project Horizon in support of access to earth and space science data. Emphasis has been placed on a design that can support a variety of data formats and applications both within and outside of astronomy. ADIL will use this tool in a variety of guises to browse and download images from the Library's collection. We see such a tool filling an important niche as a pipeline from a data repository to specialized, native data analysis software (e.g., IRAF, AIPS).

  10. Demosaicing images from colour cameras for digital image correlation

    NASA Astrophysics Data System (ADS)

    Forsey, A.; Gungor, S.

    2016-11-01

    Digital image correlation is not the intended use for consumer colour cameras, but with care they can be successfully employed in such a role. The main obstacle is the sparsely sampled colour data caused by the use of a colour filter array (CFA) to separate the colour channels. It is shown that the method used to convert consumer camera raw files into a monochrome image suitable for digital image correlation (DIC) can have a significant effect on the DIC output. A number of widely available software packages and two in-house methods are evaluated in terms of their performance when used with DIC. Using an in-plane rotating disc to produce a highly constrained displacement field, it was found that the bicubic spline based in-house demosaicing method outperformed the other methods in terms of accuracy and aliasing suppression.

  11. Analog Film Images...Back-Up Digital Technology.

    ERIC Educational Resources Information Center

    Brunner, Alex

    1999-01-01

    Examines the role of microfilm in storing information to eliminate digital obsolescence. Discusses the benefits of digital-to-analog microfilm systems; changes in conventional microfilm technology; and the advantages of true hybrid imaging systems that allow retrieval of images from document microfilm, digitally created microfilm or paper scanners…

  12. A Landsat Digital Image Rectification System

    NASA Technical Reports Server (NTRS)

    Van Wie, P.; Stein, M.

    1976-01-01

    DIRS is a Digital Image Rectification System for the geometric correction of Landsat Multispectral Scanner digital image data. DIRS removes spatial distortions from the data and brings it into conformance with the Universal Transverse Mercator (UTM) map projection. Scene data in the form of landmarks or Ground Control Points (GCPs) are used to drive the geometric correction algorithms. The system offers extensive capabilities for 'shade printing' to aid in the determination of GCPs. Affine, two dimensional least squares polynominal and spacecraft attitude modeling techniques for geometric mapping are provided. Entire scenes or selected quadralaterals may be rectified. Resampling through nearest neighbor or cubic convolution at user designated intervals is available. The output products are in the form of digital tape in band interleaved, single band or CCT format in a rotated UTM projection. The system was designed and implemented on large scale IBM 360 computers with at least 300-500K bytes of memory for user application programs and five nine track tapes plus direct access storage.

  13. Image Chain Analysis For Digital Image Rectification System

    NASA Astrophysics Data System (ADS)

    Arguello, Roger J.

    1981-07-01

    An image chain analysis, utilizing a comprehensive computer program, has been gen-erated for the key elements of a digital image rectification system. System block dia-grams and analyses for three system configurations employing film scanner input have been formulated with a parametric specification of pertinent element modulation transfer functions and input film scene spectra. The major elements of the system for this analy-sis include a high-resolution, high-speed charge-coupled device film scanner, three candidate digital resampling option algorithms (i.e., nearest neighbor, bilinear inter-polation and cubic convolution methods), and two candidate printer reconstructor implemen-tations (solid-state light-emitting diode printer and laser beam recorder). Suitable metrics for the digital rectification system, incorporating the effects of interpolation and resolution error, were established, and the image chain analysis program was used to perform a quantitative comparison of the three resampling options with the two candi-date printer reconstructor implementations. The nearest neighbor digital resampling function is found to be a good compromise choice when cascaded with either a light-emit-ting diode printer or laser beam recorder. The resulting composite intensity point spread functions, including resampling, and both types of reconstruction are bilinear and quadratic, respectively.

  14. D Point Cloud Model Colorization by Dense Registration of Digital Images

    NASA Astrophysics Data System (ADS)

    Crombez, N.; Caron, G.; Mouaddib, E.

    2015-02-01

    Architectural heritage is a historic and artistic property which has to be protected, preserved, restored and must be shown to the public. Modern tools like 3D laser scanners are more and more used in heritage documentation. Most of the time, the 3D laser scanner is completed by a digital camera which is used to enrich the accurate geometric informations with the scanned objects colors. However, the photometric quality of the acquired point clouds is generally rather low because of several problems presented below. We propose an accurate method for registering digital images acquired from any viewpoints on point clouds which is a crucial step for a good colorization by colors projection. We express this image-to-geometry registration as a pose estimation problem. The camera pose is computed using the entire images intensities under a photometric visual and virtual servoing (VVS) framework. The camera extrinsic and intrinsic parameters are automatically estimated. Because we estimates the intrinsic parameters we do not need any informations about the camera which took the used digital image. Finally, when the point cloud model and the digital image are correctly registered, we project the 3D model in the digital image frame and assign new colors to the visible points. The performance of the approach is proven in simulation and real experiments on indoor and outdoor datasets of the cathedral of Amiens, which highlight the success of our method, leading to point clouds with better photometric quality and resolution.

  15. Digital image georeferencing from a multiple camera system by GPS/INS

    NASA Astrophysics Data System (ADS)

    Mostafa, Mohamed M. R.; Schwarz, Klaus-Peter

    In this paper, the development and testing of an airborne fully digital multi-sensor system for digital mapping data acquisition is presented. The system acquires two streams of data, namely, navigation (georeferencing) data and imaging data. The navigation data are obtained by integrating an accurate strapdown inertial navigation system with a differential GPS system (DGPS). The imaging data are acquired by two low-cost digital cameras, configured in such a way so as to reduce their geometric limitations. The two cameras capture strips of overlapping nadir and oblique images. The GPS/INS-derived trajectory contains the full translational and rotational motion of the carrier aircraft. Thus, image exterior orientation information is extracted from the trajectory, during post-processing. This approach eliminates the need for ground control (GCP) when computing 3D positions of objects that appear in the field of view of the system imaging component. Two approaches for calibrating the system are presented, namely, terrestrial calibration and in-flight calibration. Test flights were conducted over the campus of The University of Calgary. Testing the system showed that best ground point positioning accuracy at 1:12,000 average image scale is 0.2 m (RMS) in easting and northing and 0.3 m (RMS) in height. Preliminary results indicate that major applications of such a system in the future are in the field of digital mapping, at scales of 1:5000 and smaller, and in the generation of digital elevation models for engineering applications.

  16. Adaptive thresholding of digital subtraction angiography images

    NASA Astrophysics Data System (ADS)

    Sang, Nong; Li, Heng; Peng, Weixue; Zhang, Tianxu

    2005-10-01

    In clinical practice, digital subtraction angiography (DSA) is a powerful technique for the visualization of blood vessels in the human body. Blood vessel segmentation is a main problem for 3D vascular reconstruction. In this paper, we propose a new adaptive thresholding method for the segmentation of DSA images. Each pixel of the DSA images is declared to be a vessel/background point with regard to a threshold and a few local characteristic limits depending on some information contained in the pixel neighborhood window. The size of the neighborhood window is set according to a priori knowledge of the diameter of vessels to make sure that each window contains the background definitely. Some experiments on cerebral DSA images are given, which show that our proposed method yields better results than global thresholding methods and some other local thresholding methods do.

  17. Approximating large convolutions in digital images.

    PubMed

    Mount, D M; Kanungo, T; Netanyahu, N S; Piatko, C; Silverman, R; Wu, A Y

    2001-01-01

    Computing discrete two-dimensional (2-D) convolutions is an important problem in image processing. In mathematical morphology, an important variant is that of computing binary convolutions, where the kernel of the convolution is a 0-1 valued function. This operation can be quite costly, especially when large kernels are involved. We present an algorithm for computing convolutions of this form, where the kernel of the binary convolution is derived from a convex polygon. Because the kernel is a geometric object, we allow the algorithm some flexibility in how it elects to digitize the convex kernel at each placement, as long as the digitization satisfies certain reasonable requirements. We say that such a convolution is valid. Given this flexibility we show that it is possible to compute binary convolutions more efficiently than would normally be possible for large kernels. Our main result is an algorithm which, given an m x n image and a k-sided convex polygonal kernel K, computes a valid convolution in O(kmn) time. Unlike standard algorithms for computing correlations and convolutions, the running time is independent of the area or perimeter of K, and our techniques do not rely on computing fast Fourier transforms. Our algorithm is based on a novel use of Bresenham's (1965) line-drawing algorithm and prefix-sums to update the convolution incrementally as the kernel is moved from one position to another across the image. PMID:18255522

  18. Digital Image Watermarking via Adaptive Logo Texturization.

    PubMed

    Andalibi, Mehran; Chandler, Damon M

    2015-12-01

    Grayscale logo watermarking is a quite well-developed area of digital image watermarking which seeks to embed into the host image another smaller logo image. The key advantage of such an approach is the ability to visually analyze the extracted logo for rapid visual authentication and other visual tasks. However, logos pose new challenges for invisible watermarking applications which need to keep the watermark imperceptible within the host image while simultaneously maintaining robustness to attacks. This paper presents an algorithm for invisible grayscale logo watermarking that operates via adaptive texturization of the logo. The central idea of our approach is to recast the watermarking task into a texture similarity task. We first separate the host image into sufficiently textured and poorly textured regions. Next, for textured regions, we transform the logo into a visually similar texture via the Arnold transform and one lossless rotation; whereas for poorly textured regions, we use only a lossless rotation. The iteration for the Arnold transform and the angle of lossless rotation are determined by a model of visual texture similarity. Finally, for each region, we embed the transformed logo into that region via a standard wavelet-based embedding scheme. We employ a multistep extraction stage, in which an affine parameter estimation is first performed to compensate for possible geometrical transformations. Testing with multiple logos on a database of host images and under a variety of attacks demonstrates that the proposed algorithm yields better overall performance than competing methods.

  19. Refined measurement of digital image texture loss

    NASA Astrophysics Data System (ADS)

    Burns, Peter D.

    2013-01-01

    Image texture is the term given to the information-bearing fluctuations such as those for skin, grass and fabrics. Since image processing aimed at reducing unwanted fluctuations (noise are other artifacts) can also remove important texture, good product design requires a balance between the two. The texture-loss MTF method, currently under international standards development, is aimed at the evaluation of digital and mobile-telephone cameras for capture of image texture. The method uses image fields of pseudo-random objects, such as overlapping disks, often referred to as `dead-leaves' targets. The analysis of these target images is based on noise-power spectrum (NPS) measurements, which are subject to estimation error. We describe a simple method for compensation of non-stationary image statistics, aimed at improving practical NPS estimates. A benign two-dimensional linear function (plane) is fit to the data and subtracted. This method was implemented and results were compared with those without compensation. The adapted analysis method resulted in reduced NPS and MTF measurement variation (20%) and low-frequency bias error. This is a particular advantage at low spatial frequencies, where texture-MTF scaling is performed. We conclude that simple trend removal should be used.

  20. Digital Image Correlation with Dynamic Subset Selection

    NASA Astrophysics Data System (ADS)

    Hassan, Ghulam Mubashar; MacNish, Cara; Dyskin, Arcady; Shufrin, Igor

    2016-09-01

    The quality of the surface pattern and selection of subset size play a critical role in achieving high accuracy in Digital Image Correlation (DIC). The subset size in DIC is normally selected by testing different subset sizes across the entire image, which is a laborious procedure. This also leads to the problem that the worst region of the surface pattern influences the performance of DIC across the entire image. In order to avoid these limitations, a Dynamic Subset Selection (DSS) algorithm is proposed in this paper to optimize the subset size for each point in an image before optimizing the correlation parameters. The proposed DSS algorithm uses the local pattern around the point of interest to calculate a parameter called the Intensity Variation Ratio (Λ), which is used to optimize the subset size. The performance of the DSS algorithm is analyzed using numerically generated images and is compared with the results of traditional DIC. Images obtained from laboratory experiments are also used to demonstrate the utility of the DSS algorithm. Results illustrate that the DSS algorithm provides a better alternative to subset size "guessing" and finds an appropriate subset size for each point of interest according to the local pattern.

  1. Classification of Images Acquired with Colposcopy Using Artificial Neural Networks

    PubMed Central

    Simões, Priscyla W; Izumi, Narjara B; Casagrande, Ramon S; Venson, Ramon; Veronezi, Carlos D; Moretti, Gustavo P; da Rocha, Edroaldo L; Cechinel, Cristian; Ceretta, Luciane B; Comunello, Eros; Martins, Paulo J; Casagrande, Rogério A; Snoeyer, Maria L; Manenti, Sandra A

    2014-01-01

    OBJECTIVE To explore the advantages of using artificial neural networks (ANNs) to recognize patterns in colposcopy to classify images in colposcopy. PURPOSE Transversal, descriptive, and analytical study of a quantitative approach with an emphasis on diagnosis. The training test e validation set was composed of images collected from patients who underwent colposcopy. These images were provided by a gynecology clinic located in the city of Criciúma (Brazil). The image database (n = 170) was divided; 48 images were used for the training process, 58 images were used for the tests, and 64 images were used for the validation. A hybrid neural network based on Kohonen self-organizing maps and multilayer perceptron (MLP) networks was used. RESULTS After 126 cycles, the validation was performed. The best results reached an accuracy of 72.15%, a sensibility of 69.78%, and a specificity of 68%. CONCLUSION Although the preliminary results still exhibit an average efficiency, the present approach is an innovative and promising technique that should be deeply explored in the context of the present study. PMID:25374454

  2. [Measuring and decoding the capabilities of digital radiographic images].

    PubMed

    Mishkinis, A B; Cherniĭ, A N; Bagaeva, N G; Il'icheva, E Iu

    2002-01-01

    The paper deals with the theory and practice of digital X-ray diagnosis. The adverse factors of formation of a digital X-ray film are considered. They included geometric and dynamic blurrinesses, blurriness of an image receiver, and the contrast and dynamic range of digital image. Analysis of a great deal of clinical data shows the capacities of digital X-ray study to diagnose different forms of pulmonary tuberculosis and other thoracic diseases. PMID:12063782

  3. Dose and diagnostic image quality in digital tomosynthesis imaging of facial bones in pediatrics

    NASA Astrophysics Data System (ADS)

    King, J. M.; Hickling, S.; Elbakri, I. A.; Reed, M.; Wrogemann, J.

    2011-03-01

    The purpose of this study was to evaluate the use of digital tomosynthesis (DT) for pediatric facial bone imaging. We compared the eye lens dose and diagnostic image quality of DT facial bone exams relative to digital radiography (DR) and computed tomography (CT), and investigated whether we could modify our current DT imaging protocol to reduce patient dose while maintaining sufficient diagnostic image quality. We measured the dose to the eye lens for all three modalities using high-sensitivity thermoluminescent dosimeters (TLDs) and an anthropomorphic skull phantom. To assess the diagnostic image quality of DT compared to the corresponding DR and CT images, we performed an observer study where the visibility of anatomical structures in the DT phantom images were rated on a four-point scale. We then acquired DT images at lower doses and had radiologists indicate whether the visibility of each structure was adequate for diagnostic purposes. For typical facial bone exams, we measured eye lens doses of 0.1-0.4 mGy for DR, 0.3-3.7 mGy for DT, and 26 mGy for CT. In general, facial bone structures were visualized better with DT then DR, and the majority of structures were visualized well enough to avoid the need for CT. DT imaging provides high quality diagnostic images of the facial bones while delivering significantly lower doses to the lens of the eye compared to CT. In addition, we found that by adjusting the imaging parameters, the DT effective dose can be reduced by up to 50% while maintaining sufficient image quality.

  4. Digital mammography, cancer screening: Factors important for image compression

    NASA Technical Reports Server (NTRS)

    Clarke, Laurence P.; Blaine, G. James; Doi, Kunio; Yaffe, Martin J.; Shtern, Faina; Brown, G. Stephen; Winfield, Daniel L.; Kallergi, Maria

    1993-01-01

    The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers.

  5. Hierarchical nucleus segmentation in digital pathology images

    NASA Astrophysics Data System (ADS)

    Gao, Yi; Ratner, Vadim; Zhu, Liangjia; Diprima, Tammy; Kurc, Tahsin; Tannenbaum, Allen; Saltz, Joel

    2016-03-01

    Extracting nuclei is one of the most actively studied topic in the digital pathology researches. Most of the studies directly search the nuclei (or seeds for the nuclei) from the finest resolution available. While the richest information has been utilized by such approaches, it is sometimes difficult to address the heterogeneity of nuclei in different tissues. In this work, we propose a hierarchical approach which starts from the lower resolution level and adaptively adjusts the parameters while progressing into finer and finer resolution. The algorithm is tested on brain and lung cancers images from The Cancer Genome Atlas data set.

  6. Digital Imaging in the Introductory Astronomy Course

    NASA Astrophysics Data System (ADS)

    Marschall, Laurence A.; Hayden, Michael B.

    The availability of small, inexpensive CCD cameras is making it possible to offer non-science students in introductory astronomy courses hands-on experience in astronomical imaging. For the past three years at Gettysburg College we have been developing laboratory exercises using ST-4, ST-6, and Lynxx CCD cameras attached to 8-inch telescopes. We discuss the hardware and the procedures involved in these exercises, pointing out the benefits and limitations of digital observations with introductory students. We also offer tips for making successful observations with students, and describe plans for further development.

  7. Hierarchical nucleus segmentation in digital pathology images

    PubMed Central

    Gao, Yi; Ratner, Vadim; Zhu, Liangjia; Diprima, Tammy; Kurc, Tahsin; Tannenbaum, Allen; Saltz, Joel

    2016-01-01

    Extracting nuclei is one of the most actively studied topic in the digital pathology researches. Most of the studies directly search the nuclei (or seeds for the nuclei) from the finest resolution available. While the richest information has been utilized by such approaches, it is sometimes difficult to address the heterogeneity of nuclei in different tissues. In this work, we propose a hierarchical approach which starts from the lower resolution level and adaptively adjusts the parameters while progressing into finer and finer resolution. The algorithm is tested on brain and lung cancers images from The Cancer Genome Atlas data set. PMID:27375315

  8. Applications Of Digital Image Acquisition In Anthropometry

    NASA Astrophysics Data System (ADS)

    Woolford, Barbara; Lewis, James L.

    1981-10-01

    Anthropometric data on reach and mobility have traditionally been collected by time consuming and relatively inaccurate manual methods. Three dimensional digital image acquisition promises to radically increase the speed and ease of data collection and analysis. A three-camera video anthropometric system for collecting position, velocity, and force data in real time is under development for the Anthropometric Measurement Laboratory at NASA's Johnson Space Center. The use of a prototype of this system for collecting data on reach capabilities and on lateral stability is described. Two extensions of this system are planned.

  9. Fatigue Crack Closure Analysis Using Digital Image Correlation

    NASA Technical Reports Server (NTRS)

    Leser, William P.; Newman, John A.; Johnston, William M.

    2010-01-01

    Fatigue crack closure during crack growth testing is analyzed in order to evaluate the critieria of ASTM Standard E647 for measurement of fatigue crack growth rates. Of specific concern is remote closure, which occurs away from the crack tip and is a product of the load history during crack-driving-force-reduction fatigue crack growth testing. Crack closure behavior is characterized using relative displacements determined from a series of high-magnification digital images acquired as the crack is loaded. Changes in the relative displacements of features on opposite sides of the crack are used to generate crack closure data as a function of crack wake position. For the results presented in this paper, remote closure did not affect fatigue crack growth rate measurements when ASTM Standard E647 was strictly followed and only became a problem when testing parameters (e.g., load shed rate, initial crack driving force, etc.) greatly exceeded the guidelines of the accepted standard.

  10. Digital Image Enhancement Techniques For Nondestructive Evaluation

    NASA Astrophysics Data System (ADS)

    Merenyi, Robert; Heller, Warren

    1986-11-01

    Computer image enhancement of digitized radiographic and conventional photographs have taken advantage of several unique state-of-the-art developments to reveal anomalies in aerospace hardware. Signal processing of such imagery at TASC includes multi-frame averaging to increase signal-to-noise levels, applying specially-developed filters to sharpen details without sacrificing image information, and performing local contrast stretch and histogram equalization to display structure in low-contrast areas. Edge detection, normally complicated in radiographic images by low-contrast, poor spatial resolution, and noise, is performed as a post-processing operation and utilizes a difference-of-Gaussians method and a least-squares fitting procedure. With these software tools, multi-image signal processing allows for the precise measurement (to within + 0.02 inches, rms) of structural motion within a rocket motor during a static test firing as well as identifying stress conditions in turbine blades and matrix anomalies in composite materials. These and other image enhancement examples of aerospace hardware analysis are detailed in the presentation.

  11. Advanced digital image archival system using MPEG technologies

    NASA Astrophysics Data System (ADS)

    Chang, Wo

    2009-08-01

    Digital information and records are vital to the human race regardless of the nationalities and eras in which they were produced. Digital image contents are produced at a rapid pace from cultural heritages via digitalization, scientific and experimental data via high speed imaging sensors, national defense satellite images from governments, medical and healthcare imaging records from hospitals, personal collection of photos from digital cameras. With these mass amounts of precious and irreplaceable data and knowledge, what standards technologies can be applied to preserve and yet provide an interoperable framework for accessing the data across varieties of systems and devices? This paper presents an advanced digital image archival system by applying the international standard of MPEG technologies to preserve digital image content.

  12. The Artist, the Color Copier, and Digital Imaging.

    ERIC Educational Resources Information Center

    Witte, Mary Stieglitz

    The impact that color-copying technology and digital imaging have had on art, photography, and design are explored. Color copiers have provided new opportunities for direct and spontaneous image making an the potential for new transformations in art. The current generation of digital color copiers permits new directions in imaging, but the…

  13. Quantitative Evaluation of Surface Color of Tomato Fruits Cultivated in Remote Farm Using Digital Camera Images

    NASA Astrophysics Data System (ADS)

    Hashimoto, Atsushi; Suehara, Ken-Ichiro; Kameoka, Takaharu

    To measure the quantitative surface color information of agricultural products with the ambient information during cultivation, a color calibration method for digital camera images and a remote monitoring system of color imaging using the Web were developed. Single-lens reflex and web digital cameras were used for the image acquisitions. The tomato images through the post-ripening process were taken by the digital camera in both the standard image acquisition system and in the field conditions from the morning to evening. Several kinds of images were acquired with the standard RGB color chart set up just behind the tomato fruit on a black matte, and a color calibration was carried out. The influence of the sunlight could be experimentally eliminated, and the calibrated color information consistently agreed with the standard ones acquired in the system through the post-ripening process. Furthermore, the surface color change of the tomato on the tree in a greenhouse was remotely monitored during maturation using the digital cameras equipped with the Field Server. The acquired digital color images were sent from the Farm Station to the BIFE Laboratory of Mie University via VPN. The time behavior of the tomato surface color change during the maturing process could be measured using the color parameter calculated based on the obtained and calibrated color images along with the ambient atmospheric record. This study is a very important step in developing the surface color analysis for both the simple and rapid evaluation of the crop vigor in the field and to construct an ambient and networked remote monitoring system for food security, precision agriculture, and agricultural research.

  14. A clinical image preference study comparing digital tomosynthesis with digital radiography for pediatric spinal imaging

    NASA Astrophysics Data System (ADS)

    King, Jenna M.; Elbakri, Idris A.; Reed, Martin; Wrogemann, Jens

    2011-03-01

    The purpose of this study was to evaluate the diagnostic quality of digital tomosynthesis (DT) images for pediatric imaging of the spine. We performed a phantom image rating study to assess the visibility of anatomical spinal structures in DT images relative to digital radiography (DR) and computed tomography (CT). We collected DT and DR images of the cervical, thoracic and lumbar spine using anthropomorphic phantoms. Four pediatric radiologists and two residents rated the visibility of structures on the DT image sets compared to DR using a four point scale (0 = not visible; 1 = visible; 2 = superior to DR; 3 = excellent, CT unnecessary). In general, the structures in the spine received ratings between 1 and 3 (cervical), or 2 and 3 (thoracic, lumbar), with a few mixed scores for structures that are usually difficult to see on diagnostic images, such as vertebrae near the cervical-thoracic joint and the apophyseal joints of the lumbar spine. The DT image sets allow most critical structures to be visualized as well or better than DR. When DR imaging is inconclusive, DT is a valuable tool to consider before sending a pediatric patient for a higher-dose CT exam.

  15. Localization of facial region in digital images

    NASA Astrophysics Data System (ADS)

    Gupta, Raj Kumar; Chowdhury, Aditya; Roy, Rahul

    2011-06-01

    We have developed and implemented an algorithm for the localization of facial region in a digital image consisting of multiple faces. The algorithm utilizes the basic colour-segmentation methods where the skin and hair regions are identified using the standard colour models. However, the implementation of merely the skin and hair models yields both the facial and non-facial regions. In order to filter out the non-facial region, we have introduced a quantization and a filtering module. The filter module essentially evaluates the proximity of the connected components associated with that of skin and hair regions. We have tested the algorithm on various images under various conditions. We found that the algorithm is capable of localizing the facial region even in a harsh condition.

  16. Image manipulation: Fraudulence in digital dental records: Study and review

    PubMed Central

    Chowdhry, Aman; Sircar, Keya; Popli, Deepika Bablani; Tandon, Ankita

    2014-01-01

    Introduction: In present-day times, freely available software allows dentists to tweak their digital records as never before. But, there is a fine line between acceptable enhancements and scientific delinquency. Aims and Objective: To manipulate digital images (used in forensic dentistry) of casts, lip prints, and bite marks in order to highlight tampering techniques and methods of detecting and preventing manipulation of digital images. Materials and Methods: Digital image records of forensic data (casts, lip prints, and bite marks photographed using Samsung Techwin L77 digital camera) were manipulated using freely available software. Results: Fake digital images can be created either by merging two or more digital images, or by altering an existing image. Discussion and Conclusion: Retouched digital images can be used for fraudulent purposes in forensic investigations. However, tools are available to detect such digital frauds, which are extremely difficult to assess visually. Thus, all digital content should mandatorily have attached metadata and preferably watermarking in order to avert their malicious re-use. Also, computer alertness, especially about imaging software's, should be promoted among forensic odontologists/dental professionals. PMID:24696587

  17. Estimation of color modification in digital images by CFA pattern change.

    PubMed

    Choi, Chang-Hee; Lee, Hae-Yeoun; Lee, Heung-Kyu

    2013-03-10

    Extensive studies have been carried out for detecting image forgery such as copy-move, re-sampling, blurring, and contrast enhancement. Although color modification is a common forgery technique, there is no reported forensic method for detecting this type of manipulation. In this paper, we propose a novel algorithm for estimating color modification in images acquired from digital cameras when the images are modified. Most commercial digital cameras are equipped with a color filter array (CFA) for acquiring the color information of each pixel. As a result, the images acquired from such digital cameras include a trace from the CFA pattern. This pattern is composed of the basic red green blue (RGB) colors, and it is changed when color modification is carried out on the image. We designed an advanced intermediate value counting method for measuring the change in the CFA pattern and estimating the extent of color modification. The proposed method is verified experimentally by using 10,366 test images. The results confirmed the ability of the proposed method to estimate color modification with high accuracy.

  18. Digital image-based classification of biodiesel.

    PubMed

    Costa, Gean Bezerra; Fernandes, David Douglas Sousa; Almeida, Valber Elias; Araújo, Thomas Souto Policarpo; Melo, Jessica Priscila; Diniz, Paulo Henrique Gonçalves Dias; Véras, Germano

    2015-07-01

    This work proposes a simple, rapid, inexpensive, and non-destructive methodology based on digital images and pattern recognition techniques for classification of biodiesel according to oil type (cottonseed, sunflower, corn, or soybean). For this, differing color histograms in RGB (extracted from digital images), HSI, Grayscale channels, and their combinations were used as analytical information, which was then statistically evaluated using Soft Independent Modeling by Class Analogy (SIMCA), Partial Least Squares Discriminant Analysis (PLS-DA), and variable selection using the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA). Despite good performances by the SIMCA and PLS-DA classification models, SPA-LDA provided better results (up to 95% for all approaches) in terms of accuracy, sensitivity, and specificity for both the training and test sets. The variables selected Successive Projections Algorithm clearly contained the information necessary for biodiesel type classification. This is important since a product may exhibit different properties, depending on the feedstock used. Such variations directly influence the quality, and consequently the price. Moreover, intrinsic advantages such as quick analysis, requiring no reagents, and a noteworthy reduction (the avoidance of chemical characterization) of waste generation, all contribute towards the primary objective of green chemistry.

  19. Digital image-based classification of biodiesel.

    PubMed

    Costa, Gean Bezerra; Fernandes, David Douglas Sousa; Almeida, Valber Elias; Araújo, Thomas Souto Policarpo; Melo, Jessica Priscila; Diniz, Paulo Henrique Gonçalves Dias; Véras, Germano

    2015-07-01

    This work proposes a simple, rapid, inexpensive, and non-destructive methodology based on digital images and pattern recognition techniques for classification of biodiesel according to oil type (cottonseed, sunflower, corn, or soybean). For this, differing color histograms in RGB (extracted from digital images), HSI, Grayscale channels, and their combinations were used as analytical information, which was then statistically evaluated using Soft Independent Modeling by Class Analogy (SIMCA), Partial Least Squares Discriminant Analysis (PLS-DA), and variable selection using the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA). Despite good performances by the SIMCA and PLS-DA classification models, SPA-LDA provided better results (up to 95% for all approaches) in terms of accuracy, sensitivity, and specificity for both the training and test sets. The variables selected Successive Projections Algorithm clearly contained the information necessary for biodiesel type classification. This is important since a product may exhibit different properties, depending on the feedstock used. Such variations directly influence the quality, and consequently the price. Moreover, intrinsic advantages such as quick analysis, requiring no reagents, and a noteworthy reduction (the avoidance of chemical characterization) of waste generation, all contribute towards the primary objective of green chemistry. PMID:25882407

  20. Reliability-guided digital image correlation for image deformation measurement

    SciTech Connect

    Pan Bing

    2009-03-10

    A universally applicable reliability-guided digital image correlation (DIC) method is proposed for reliable image deformation measurement. The zero-mean normalized cross correlation (ZNCC) coefficient is used to identify the reliability of the point computed. The correlation calculation begins with a seed point and is then guided by the ZNCC coefficient. That means the neighbors of the point with the highest ZNCC coefficient in a queue for computed points will be processed first. Thus the calculation path is always along the most reliable direction, and possible error propagation of the conventional DIC method can be avoided. The proposed novel DIC method is universally applicable to the images with shadows, discontinuous areas, and deformation discontinuity. Two image pairs were used to evaluate the performance of the proposed technique, and the successful results clearly demonstrate its robustness and effectiveness.

  1. Image restoration for TV-scan moving images acquired through a semiconductor backscattered electron detector.

    PubMed

    Oho, Eisaku; Suzuki, Kazuhiko

    2009-01-01

    A semiconductor backscattered electron (BSE) detector has become popular in scanning electron microscopy session. However, detectors of semiconductor type have a serious disadvantage on the frequency characteristics. As a result, fast scan (e.g. TV-scan) BSE image should be blurred remarkably. It is the purpose of this study to restore this degradation by using digital image processing technology. In order to improve it practically, we have to settle several problems, such as noise, undesirable processing artifacts, and ease of use. Image processing techniques in an impromptu manner like a conventional mask processing are unhelpful for this study, because a complicated degradation of output signal affects severely the phase response as well as the amplitude response of our SEM system. Hence, based on the characteristics of an SEM signal obtained from the semiconductor BSE detector, a proper inverse filter in Fourier domain is designed successfully. Finally, the inverse filter is converted to a special convolution mask, which is skillfully designed, and applied for TV-scan moving BSE images. The improved BSE image is very effective in the work for finding important objects.

  2. Update on digital image management and PACS.

    PubMed

    Ratib, O; Ligier, Y; Bandon, D; Valentino, D

    2000-01-01

    Information technology is becoming a vital component of all health care enterprises, from managed care services to large hospital networks, that provides the basis of electronic patient records and hospital-wide information. The rationale behind such systems is deceptively simple: physicians want to sit down at a single workstation and call up all information, both clinical data and medical images, concerning a given patient. Picture archiving and communication systems (PACS) are responsible for solving the problem of acquiring, transmitting, and displaying radiologic images. The major benefit of PACS resides in its ability to communicate images and reports to referring physicians in a timely and reliable fashion. With the changes in economics and the shift toward managed and capitated care, the teleradiology component of PACS is rapidly gaining momentum. In allowing remote coverage of multiple sites by the same radiologists and remote consultations and expert opinion, teleradiology is in many instances the only option to maintain economically viable radiologic settings. The technical evolution toward more integrated systems and the shift toward Web-based technology is rapidly merging the two concepts of PACS and teleradiology in global image management and communication systems.

  3. Remote sensing in marine environment - acquiring, processing, and interpreting GLORIA sidescan sonor images of deep sea floor

    SciTech Connect

    O'Leary, D.W.

    1989-03-01

    The US Geological Survey's remote sensing instrument for regional imaging of the deep sea floor (> 400 m water depth) is the GLORIA (Geologic Long-Range Inclined Asdic) sidescan sonar system, designed and operated by the British Institute of Oceanographic Sciences. A 30-sec sweep rate provides for a swath width of approximately 45 km, depending on water depth. The return signal is digitally recorded as 8 bit data to provide a cross-range pixel dimension of 50 m. Postcruise image processing is carried out by using USGS software. Processing includes precision water-column removal, geometric and radiometric corrections, and contrast enhancement. Mosaicking includes map grid fitting, concatenation, and tone matching. Seismic reflection profiles, acquired along track during the survey, are image correlative and provide a subsurface dimension unique to marine remote sensing. Generally GLORIA image interpretation is based on brightness variations which are largely a function of (1) surface roughness at a scale of approximately 1 m and (2) slope changes of more than about 4/degrees/ over distances of at least 50 m. Broader, low-frequency changes in slope that cannot be detected from the Gloria data can be determined from seismic profiles. Digital files of bathymetry derived from echo-sounder data can be merged with GLORIA image data to create relief models of the sea floor for geomorphic interpretation of regional slope effects.

  4. Digital image-based flame emission spectrometry.

    PubMed

    Silva Lyra, Wellington; Dos Santos, Vagner Bezerra; Dionízio, Amália Geiza Gama; Martins, Valdomiro Lacerda; Almeida, Luciano Farias; Nóbrega Gaião, Edvaldo; Diniz, Paulo Henrique Gonçalves Dias; Silva, Edvan Cirino; Araújo, Mário César Ugulino

    2009-03-15

    A digital image-based flame emission spectrometric (DIB-FES) method for the quantitative chemical analysis is proposed here for the first time. The DIB-FES method employs a webcam to capture the digital images which are associated to a radiation emitted by the analyte into an air-butane flame. Since the detection by webcam is based on the RGB (red-green-blue) colour system, a novel mathematical model was developed in order to build DIB-FES analytical curves and estimate figures of merit for the proposed method. In this approach, each image is retrieved in the three R, G and B individual components and their values were used to define a position vector in RGB three-dimensional space. The norm of this vector is then adopted as the RGB-based value (analytical response) and it has revealed to be linearly related to the analyte concentration. The feasibility of the DIB-FES method is illustrated in three applications involving the determination of lithium, sodium and calcium in anti-depressive drug, physiological serum and water, respectively. In comparison with the traditional flame emission spectrometry (trad-FES), no statistic difference has been observed between the results by applying the paired t-test at the 95% confidence level. However, the DIB-FES method has offered the largest sensitivities and precision, as well as the smallest limits of detection and quantification for the three analytes. These advantageous characteristics are attributed to the trivariate nature of the detection by webcam. PMID:19159768

  5. Avoiding Twisted Pixels: Ethical Guidelines for the Appropriate Use and Manipulation of Scientific Digital Images

    PubMed Central

    2014-01-01

    Digital imaging has provided scientists with new opportunities to acquire and manipulate data using techniques that were difficult or impossible to employ in the past. Because digital images are easier to manipulate than film images, new problems have emerged. One growing concern in the scientific community is that digital images are not being handled with sufficient care. The problem is twofold: (1) the very small, yet troubling, number of intentional falsifications that have been identified, and (2) the more common unintentional, inappropriate manipulation of images for publication. Journals and professional societies have begun to address the issue with specific digital imaging guidelines. Unfortunately, the guidelines provided often do not come with instructions to explain their importance. Thus they deal with what should or should not be done, but not the associated ‘why’ that is required for understanding the rules. This article proposes 12 guidelines for scientific digital image manipulation and discusses the technical reasons behind these guidelines. These guidelines can be incorporated into lab meetings and graduate student training in order to provoke discussion and begin to bring an end to the culture of “data beautification”. PMID:20567932

  6. A color image processing pipeline for digital microscope

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Liu, Peng; Zhuang, Zhefeng; Chen, Enguo; Yu, Feihong

    2012-10-01

    Digital microscope has found wide application in the field of biology, medicine et al. A digital microscope differs from traditional optical microscope in that there is no need to observe the sample through an eyepiece directly, because the optical image is projected directly on the CCD/CMOS camera. However, because of the imaging difference between human eye and sensor, color image processing pipeline is needed for the digital microscope electronic eyepiece to get obtain fine image. The color image pipeline for digital microscope, including the procedures that convert the RAW image data captured by sensor into real color image, is of great concern to the quality of microscopic image. The color pipeline for digital microscope is different from digital still cameras and video cameras because of the specific requirements of microscopic image, which should have the characters of high dynamic range, keeping the same color with the objects observed and a variety of image post-processing. In this paper, a new color image processing pipeline is proposed to satisfy the requirements of digital microscope image. The algorithm of each step in the color image processing pipeline is designed and optimized with the purpose of getting high quality image and accommodating diverse user preferences. With the proposed pipeline implemented on the digital microscope platform, the output color images meet the various analysis requirements of images in the medicine and biology fields very well. The major steps of color imaging pipeline proposed include: black level adjustment, defect pixels removing, noise reduction, linearization, white balance, RGB color correction, tone scale correction and gamma correction.

  7. Measuring visual opacity using digital imaging technology.

    PubMed

    McFarland, Michael J; Terry, Spencer H; Calidonna, Michael J; Stone, Daniel A; Kerch, Paul E; Rasmussen, Steven L

    2004-03-01

    The U.S. Environmental Protection Agency (EPA) Reference Method 9 (Method 9) is the preferred enforcement approach for verifying facility compliance with federal visible opacity standards. Supporters of Method 9 have cited its flexibility and low cost as important technological and economic advantages of the methodology. The Digital Opacity Compliance System (DOCS), an innovative technology that employs digital imaging technology for quantifying visible opacity, has been proposed as a technically defensible and economically competitive alternative to Method 9. Results from the field application of the DOCS at EPA-approved Method 9 smoke schools located in Ogden, UT, Augusta, GA, and Columbus, OH, demonstrated that, under clear sky conditions, the DOCS consistently met the opacity error rate established under Method 9. Application of hypothesis testing on the smoke school data set confirmed that the DOCS was equivalent to Method 9 under clear sky conditions. Under overcast sky conditions, human observers seemed to be more accurate than the DOCS in measuring opacity. However, within the smoke school environment, human observers routinely employ backgrounds other than sky (e.g., trees, telephone poles, billboards) to quantify opacity on overcast days. Under conditions that compel the use of sky as plume background (e.g., emission stacks having heights above the tree line), the DOCS appears to be a more accurate methodology for quantifying opacity than are human observers.

  8. Counterfeit deterrence and digital imaging technology

    NASA Astrophysics Data System (ADS)

    Church, Sara E.; Fuller, Reese H.; Jaffe, Annette B.; Pagano, Lorelei W.

    2000-04-01

    The US government recognizes the growing problem of counterfeiting currency using digital imaging technology, as desktop systems become more sophisticated, less expensive and more prevalent. As the rate of counterfeiting with this type of equipment has grown, the need for specific prevention methods has become apparent to the banknote authorities. As a result, the Treasury Department and Federal Reserve have begun to address issues related specifically to this type of counterfeiting. The technical representatives of these agencies are taking a comprehensive approach to minimize counterfeiting using digital technology. This approach includes identification of current technology solutions for banknote recognition, data stream intervention and output marking, outreach to the hardware and software industries and enhancement of public education efforts. Other aspects include strong support and cooperation with existing international efforts to prevent counterfeiting, review and amendment of existing anti- counterfeiting legislation and investigation of currency design techniques to make faithful reproduction more difficult. Implementation of these steps and others are to lead to establishment of a formal, permanent policy to address and prevent the use of emerging technologies to counterfeit currency.

  9. Digital camera with apparatus for authentication of images produced from an image file

    NASA Technical Reports Server (NTRS)

    Friedman, Gary L. (Inventor)

    1993-01-01

    A digital camera equipped with a processor for authentication of images produced from an image file taken by the digital camera is provided. The digital camera processor has embedded therein a private key unique to it, and the camera housing has a public key that is so uniquely based upon the private key that digital data encrypted with the private key by the processor may be decrypted using the public key. The digital camera processor comprises means for calculating a hash of the image file using a predetermined algorithm, and second means for encrypting the image hash with the private key, thereby producing a digital signature. The image file and the digital signature are stored in suitable recording means so they will be available together. Apparatus for authenticating at any time the image file as being free of any alteration uses the public key for decrypting the digital signature, thereby deriving a secure image hash identical to the image hash produced by the digital camera and used to produce the digital signature. The apparatus calculates from the image file an image hash using the same algorithm as before. By comparing this last image hash with the secure image hash, authenticity of the image file is determined if they match, since even one bit change in the image hash will cause the image hash to be totally different from the secure hash.

  10. Advanced digital detectors for neutron imaging.

    SciTech Connect

    Doty, F. Patrick

    2003-12-01

    Neutron interrogation provides unique information valuable for Nonproliferation & Materials Control and other important applications including medicine, airport security, protein crystallography, and corrosion detection. Neutrons probe deep inside massive objects to detect small defects and chemical composition, even through high atomic number materials such as lead. However, current detectors are bulky gas-filled tubes or scintillator/PM tubes, which severely limit many applications. Therefore this project was undertaken to develop new semiconductor radiation detection materials to develop the first direct digital imaging detectors for neutrons. The approach relied on new discovery and characterization of new solid-state sensor materials which convert neutrons directly to electronic signals via reactions BlO(n,a)Li7 and Li6(n,a)T.

  11. Image Resolution in the Digital Era: Notion and Clinical Implications

    PubMed Central

    Rakhshan, Vahid

    2014-01-01

    Digital radiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digital radiographs. PMID:25469352

  12. Image resolution in the digital era: notion and clinical implications.

    PubMed

    Rakhshan, Vahid

    2014-12-01

    Digital radiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digital radiographs. PMID:25469352

  13. Digital Mammography Imaging: Breast Tomosynthesis and Advanced Applications

    PubMed Central

    Helvie, Mark A.

    2011-01-01

    Synopsis This article discusses recent developments in advanced derivative technologies associated with digital mammography. Digital breast tomosynthesis – its principles, development, and early clinical trials are reviewed. Contrast enhanced digital mammography and combined imaging systems with digital mammography and ultrasound are also discussed. Although all these methods are currently research programs, they hold promise for improving cancer detection and characterization if early results are confirmed by clinical trials. PMID:20868894

  14. Automation of Axisymmetric Drop Shape Analysis Using Digital Image Processing

    NASA Astrophysics Data System (ADS)

    Cheng, Philip Wing Ping

    The Axisymmetric Drop Shape Analysis - Profile (ADSA-P) technique, as initiated by Rotenberg, is a user -oriented scheme to determine liquid-fluid interfacial tensions and contact angles from the shape of axisymmetric menisci, i.e., from sessile as well as pendant drops. The ADSA -P program requires as input several coordinate points along the drop profile, the value of the density difference between the bulk phases, and gravity. The solution yields interfacial tension and contact angle. Although the ADSA-P technique was in principle complete, it was found that it was of very limited practical use. The major difficulty with the method is the need for very precise coordinate points along the drop profile, which, up to now, could not be obtained readily. In the past, the coordinate points along the drop profile were obtained by manual digitization of photographs or negatives. From manual digitization data, the surface tension values obtained had an average error of +/-5% when compared with literature values. Another problem with the ADSA-P technique was that the computer program failed to converge for the case of very elongated pendant drops. To acquire the drop profile coordinates automatically, a technique which utilizes recent developments in digital image acquisition and analysis was developed. In order to determine the drop profile coordinates as precisely as possible, the errors due to optical distortions were eliminated. In addition, determination of drop profile coordinates to pixel and sub-pixel resolution was developed. It was found that high precision could be obtained through the use of sub-pixel resolution and a spline fitting method. The results obtained using the automatic digitization technique in conjunction with ADSA-P not only compared well with the conventional methods, but also outstripped the precision of conventional methods considerably. To solve the convergence problem of very elongated pendant drops, it was found that the reason for the

  15. X-ray imaging using digital cameras

    NASA Astrophysics Data System (ADS)

    Winch, Nicola M.; Edgar, Andrew

    2012-03-01

    The possibility of using the combination of a computed radiography (storage phosphor) cassette and a semiprofessional grade digital camera for medical or dental radiography is investigated. We compare the performance of (i) a Canon 5D Mk II single lens reflex camera with f1.4 lens and full-frame CMOS array sensor and (ii) a cooled CCD-based camera with a 1/3 frame sensor and the same lens system. Both systems are tested with 240 x 180 mm cassettes which are based on either powdered europium-doped barium fluoride bromide or needle structure europium-doped cesium bromide. The modulation transfer function for both systems has been determined and falls to a value of 0.2 at around 2 lp/mm, and is limited by light scattering of the emitted light from the storage phosphor rather than the optics or sensor pixelation. The modulation transfer function for the CsBr:Eu2+ plate is bimodal, with a high frequency wing which is attributed to the light-guiding behaviour of the needle structure. The detective quantum efficiency has been determined using a radioisotope source and is comparatively low at 0.017 for the CMOS camera and 0.006 for the CCD camera, attributed to the poor light harvesting by the lens. The primary advantages of the method are portability, robustness, digital imaging and low cost; the limitations are the low detective quantum efficiency and hence signal-to-noise ratio for medical doses, and restricted range of plate sizes. Representative images taken with medical doses are shown and illustrate the potential use for portable basic radiography.

  16. Digital Archival Image Collections: Who Are the Users?

    ERIC Educational Resources Information Center

    Herold, Irene M. H.

    2010-01-01

    Archival digital image collections are a relatively new phenomenon in college library archives. Digitizing archival image collections may make them accessible to users worldwide. There has been no study to explore whether collections on the Internet lead to users who are beyond the institution or a comparison of users to a national or…

  17. User-Driven Planning for Digital-Image Delivery

    ERIC Educational Resources Information Center

    Pisciotta, Henry; Halm, Michael J.; Dooris, Michael J.

    2006-01-01

    This article draws on two projects funded by the Andrew W. Mellon Foundation concerning the ways colleges and universities can support the legitimate sharing of digital learning resources for scholarly use. The 2001-03 Visual Image User Study (VIUS) assessed the scholarly needs of digital image users-faculty, staff, and students. That study led to…

  18. Losing images in digital radiology: more than you think.

    PubMed

    Oglevee, Catherine; Pianykh, Oleg

    2015-06-01

    It is a common belief that the shift to digital imaging some 20 years ago helped medical image exchange and got rid of any potential image loss that was happening with printed image films. Unfortunately, this is not the case: despite the most recent advances in digital imaging, most hospitals still keep losing their imaging data, with these losses going completely unnoticed. As a result, not only does image loss affect the faith in digital imaging but it also affects patient diagnosis and daily quality of clinical work. This paper identifies the origins of invisible image losses, provides methods and procedures to detect image loss, and demonstrates modes of action that can be taken to stop the problem from happening. PMID:25514841

  19. Digital image fusion systems: color imaging and low-light targets

    NASA Astrophysics Data System (ADS)

    Estrera, Joseph P.

    2009-05-01

    This paper presents digital image fusion (enhanced A+B) systems in color imaging and low light target applications. This paper will discuss first the digital sensors that are utilized in the noted image fusion applications which is a 1900x1086 (high definition format) CMOS imager coupled to a Generation III image intensifier for the visible/near infrared (NIR) digital sensor and 320x240 or 640x480 uncooled microbolometer thermal imager for the long wavelength infrared (LWIR) digital sensor. Performance metrics for these digital imaging sensors will be presented. The digital image fusion (enhanced A+B) process will be presented in context of early fused night vision systems such as the digital image fused system (DIFS) and the digital enhanced night vision goggle and later, the long range digitally fused night vision sighting system. Next, this paper will discuss the effects of user display color in a dual color digital image fusion system. Dual color image fusion schemes such as Green/Red, Cyan/Yellow, and White/Blue for image intensifier and thermal infrared sensor color representation, respectively, are discussed. Finally, this paper will present digitally fused imagery and image analysis of long distance targets in low light from these digital fused systems. The result of this image analysis with enhanced A+B digital image fusion systems is that maximum contrast and spatial resolution is achieved in a digital fusion mode as compared to individual sensor modalities in low light, long distance imaging applications. Paper has been cleared by DoD/OSR for Public Release under Ref: 08-S-2183 on August 8, 2008.

  20. Geometric processing of digital images of the planets

    NASA Technical Reports Server (NTRS)

    Edwards, Kathleen

    1987-01-01

    New procedures and software have been developed for geometric transformation of images to support digital cartography of the planets. The procedures involve the correction of spacecraft camera orientation of each image with the use of ground control and the transformation of each image to a Sinusoidal Equal-Area map projection with an algorithm which allows the number of transformation calculations to vary as the distortion varies within the image. When the distortion is low in an area of an image, few transformation computations are required, and most pixels can be interpolated. When distortion is extreme, the location of each pixel is computed. Mosaics are made of these images and stored as digital databases. Completed Sinusoidal databases may be used for digital analysis and registration with other spatial data. They may also be reproduced as published image maps by digitally transforming them to appropriate map projections.

  1. Geometric processing of digital images of the planets

    NASA Astrophysics Data System (ADS)

    Edwards, K.

    1987-09-01

    New procedures and software have been developed for geometric transformation of images to support digital cartography of the planets. The procedures involve the correction of spacecraft camera orientation of each image with the use of ground control and the transformation of each image to a Sinusoidal Equal-Area map projection with an algorithm which allows the number of transformation calculations to vary as the distortion varies within the image. When the distortion is low in an area of an image, few transformation computations are required, and most pixels can be interpolated. When distortion is extreme, the location of each pixel is computed. Mosaics are made of these images and stored as digital databases. Completed Sinusoidal databases may be used for digital analysis and registration with other spatial data. They may also be reproduced as published image maps by digitally transforming them to appropriate map projections.

  2. System for objective assessment of image differences in digital cinema

    NASA Astrophysics Data System (ADS)

    Fliegel, Karel; Krasula, Lukáš; Páta, Petr; Myslík, Jiří; Pecák, Josef; Jícha, Marek

    2014-09-01

    There is high demand for quick digitization and subsequent image restoration of archived film records. Digitization is very urgent in many cases because various invaluable pieces of cultural heritage are stored on aging media. Only selected records can be reconstructed perfectly using painstaking manual or semi-automatic procedures. This paper aims to answer the question what are the quality requirements on the restoration process in order to obtain acceptably close visual perception of the digitally restored film in comparison to the original analog film copy. This knowledge is very important to preserve the original artistic intention of the movie producers. Subjective experiment with artificially distorted images has been conducted in order to answer the question what is the visual impact of common image distortions in digital cinema. Typical color and contrast distortions were introduced and test images were presented to viewers using digital projector. Based on the outcome of this subjective evaluation a system for objective assessment of image distortions has been developed and its performance tested. The system utilizes calibrated digital single-lens reflex camera and subsequent analysis of suitable features of images captured from the projection screen. The evaluation of captured image data has been optimized in order to obtain predicted differences between the reference and distorted images while achieving high correlation with the results of subjective assessment. The system can be used to objectively determine the difference between analog film and digital cinema images on the projection screen.

  3. A novel super resolution scheme to acquire and process satellite images

    NASA Astrophysics Data System (ADS)

    Yin, Dong-yu; Su, Xiao-feng; Lin, Jian-chun; Wang, Gan-quan; Kuang, Ding-bo

    2013-09-01

    Geosynchronous satellite has obvious limitations for the weight and the scale of payloads, and large aperture optical system is not permitted. The optical diffraction limit of small aperture optical system has an adverse impact on the resolution of the acquired images. Therefore, how to get high resolution images using super-resolution technique with the acquired low resolution images becomes a popular problem investigated by researchers. Here, we present a novel scheme to acquire low resolution images and process them to achieve a high resolution image. Firstly, to acquire low resolution images, we adopt a special arrangement pattern of four CCD staggered arrays on the focal plane in the remote sensing satellite framework .These four CCD linear arrays are parallelized with a 0.25√2 pixel shift along the CCD direction and a 1.25 pixel shift along the scanning direction. The rotation angle between the two directions is 45 degree. The tilting sampling mode and the special arrangement pattern allow the sensor to acquire images with a smaller sampling interval which can give the resolution a greater enhancement. Secondly, to reconstruct a high resolution image of pretty good quality with a magnification factor 4, we propose a novel algorithm based on the iterative-interpolation super resolution algorithm (IISR) and the new edge-directed interpolation algorithm (NEDI). The new algorithm makes a critical improvement to NEDI and introduces it into the multi-frame interpolation in IISR. The algorithm can preserve the edges well and requires a relatively small number of low-resolution images to achieve better reconstruction accuracy .In the last part of the paper, we carry out a simulation experiment, and use MSE as the quality measure. The results demonstrate that our new scheme substantially improves the image resolution with both better quantitative quality and visual quality compared with some previous normal methods.

  4. Digital Camera with Apparatus for Authentication of Images Produced from an Image File

    NASA Technical Reports Server (NTRS)

    Friedman, Gary L. (Inventor)

    1996-01-01

    A digital camera equipped with a processor for authentication of images produced from an image file taken by the digital camera is provided. The digital camera processor has embedded therein a private key unique to it, and the camera housing has a public key that is so uniquely related to the private key that digital data encrypted with the private key may be decrypted using the public key. The digital camera processor comprises means for calculating a hash of the image file using a predetermined algorithm, and second means for encrypting the image hash with the private key, thereby producing a digital signature. The image file and the digital signature are stored in suitable recording means so they will be available together. Apparatus for authenticating the image file as being free of any alteration uses the public key for decrypting the digital signature, thereby deriving a secure image hash identical to the image hash produced by the digital camera and used to produce the digital signature. The authenticating apparatus calculates from the image file an image hash using the same algorithm as before. By comparing this last image hash with the secure image hash, authenticity of the image file is determined if they match. Other techniques to address time-honored methods of deception, such as attaching false captions or inducing forced perspectives, are included.

  5. Effects of scatter radiation on reconstructed images in digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Liu, Bob; Li, Xinhua

    2009-02-01

    We evaluated the effects of scatter radiation on the reconstructed images in digital breast tomosynthesis. Projection images of a 6 cm anthropomorphic breast phantom were acquired using a Hologic prototype digital breast tomosynthesis system. Scatter intensities in projection images were sampled with a beam stop method. The scatter intensity at any pixel was obtained by two dimensional fitting. Primary-only projection images were generated by subtracting the scatter contributions from the original projection images. The 3-dimensional breast was reconstructed first based on original projection images which contained the contributions from both primary rays and scattered radiation using three different reconstruction algorithms. The same breast volume was reconstructed again using the same algorithms but based on primaryonly projection images. The image artifacts, pixel value difference to noise ratio (PDNR), and detected image features in these two sets of reconstructed slices were compared to evaluate the effects of scatter radiation. It was found that the scatter radiation caused inaccurate reconstruction of the x-ray attenuation property of the tissue. X-ray attenuation coefficients could be significantly underestimated in the region where scatter intensity is high. This phenomenon is similar to the cupping artifacts found in computed tomography. The scatter correction is important if accurate x-ray attenuation of the tissues is needed. No significant improvement in terms of numbers of detected image features was observed after scatter correction. More sophisticated phantom dedicated to digital breast tomosynthesis may be needed for further evaluation.

  6. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Slot Thing, Rune; Bernchou, Uffe; Mainegra-Hing, Ernesto; Hansen, Olfred; Brink, Carsten

    2016-08-01

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five lung cancer patients. Projection image based artefact corrections of image lag, detector scatter, body scatter and beam hardening are described and applied to CBCT images of five lung cancer patients. Image quality is evaluated through visual appearance of the reconstructed images, HU-correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs and the reference CT images are reduced by 31% when using the artefact corrections compared to the standard clinical CBCT reconstruction. A versatile artefact correction method for clinical CBCT images acquired for IGRT has been developed. HU values are recovered in the corrected CBCT images. The proposed method relies on post processing of clinical projection images, and does not require patient specific optimisation. It is thus a powerful tool for image quality improvement of large numbers of CBCT images.

  7. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy.

    PubMed

    Thing, Rune Slot; Bernchou, Uffe; Mainegra-Hing, Ernesto; Hansen, Olfred; Brink, Carsten

    2016-08-01

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five lung cancer patients. Projection image based artefact corrections of image lag, detector scatter, body scatter and beam hardening are described and applied to CBCT images of five lung cancer patients. Image quality is evaluated through visual appearance of the reconstructed images, HU-correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs and the reference CT images are reduced by 31% when using the artefact corrections compared to the standard clinical CBCT reconstruction. A versatile artefact correction method for clinical CBCT images acquired for IGRT has been developed. HU values are recovered in the corrected CBCT images. The proposed method relies on post processing of clinical projection images, and does not require patient specific optimisation. It is thus a powerful tool for image quality improvement of large numbers of CBCT images.

  8. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy.

    PubMed

    Thing, Rune Slot; Bernchou, Uffe; Mainegra-Hing, Ernesto; Hansen, Olfred; Brink, Carsten

    2016-08-01

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five lung cancer patients. Projection image based artefact corrections of image lag, detector scatter, body scatter and beam hardening are described and applied to CBCT images of five lung cancer patients. Image quality is evaluated through visual appearance of the reconstructed images, HU-correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs and the reference CT images are reduced by 31% when using the artefact corrections compared to the standard clinical CBCT reconstruction. A versatile artefact correction method for clinical CBCT images acquired for IGRT has been developed. HU values are recovered in the corrected CBCT images. The proposed method relies on post processing of clinical projection images, and does not require patient specific optimisation. It is thus a powerful tool for image quality improvement of large numbers of CBCT images. PMID:27405692

  9. Modeling digital breast tomosynthesis imaging systems for optimization studies

    NASA Astrophysics Data System (ADS)

    Lau, Beverly Amy

    Digital breast tomosynthesis (DBT) is a new imaging modality for breast imaging. In tomosynthesis, multiple images of the compressed breast are acquired at different angles, and the projection view images are reconstructed to yield images of slices through the breast. One of the main problems to be addressed in the development of DBT is the optimal parameter settings to obtain images ideal for detection of cancer. Since it would be unethical to irradiate women multiple times to explore potentially optimum geometries for tomosynthesis, it is ideal to use a computer simulation to generate projection images. Existing tomosynthesis models have modeled scatter and detector without accounting for oblique angles of incidence that tomosynthesis introduces. Moreover, these models frequently use geometry-specific physical factors measured from real systems, which severely limits the robustness of their algorithms for optimization. The goal of this dissertation was to design the framework for a computer simulation of tomosynthesis that would produce images that are sensitive to changes in acquisition parameters, so an optimization study would be feasible. A computer physics simulation of the tomosynthesis system was developed. The x-ray source was modeled as a polychromatic spectrum based on published spectral data, and inverse-square law was applied. Scatter was applied using a convolution method with angle-dependent scatter point spread functions (sPSFs), followed by scaling using an angle-dependent scatter-to-primary ratio (SPR). Monte Carlo simulations were used to generate sPSFs for a 5-cm breast with a 1-cm air gap. Detector effects were included through geometric propagation of the image onto layers of the detector, which were blurred using depth-dependent detector point-spread functions (PRFs). Depth-dependent PRFs were calculated every 5-microns through a 200-micron thick CsI detector using Monte Carlo simulations. Electronic noise was added as Gaussian noise as a

  10. RADIOPACITY OF RESTORATIVE MATERIALS USING DIGITAL IMAGES

    PubMed Central

    Salzedas, Leda Maria Pescinini; Louzada, Mário Jefferson Quirino; de Oliveira, Antonio Braz

    2006-01-01

    The radiopacity of esthetic restorative materials has been established as an important requirement, improving the radiographic diagnosis. The aim of this study was to evaluate the radiopacity of six restorative materials using a direct digital image system, comparing them to the dental tissues (enamel-dentin), expressed as equivalent thickness of aluminum (millimeters of aluminum). Five specimens of each material were made. Three 2-mm thick longitudinal sections were cut from an intact extracted permanent molar tooth (including enamel and dentin). An aluminum step wedge with 9 steps was used. The samples of different materials were placed on a phosphor plate together with a tooth section, aluminum step wedge and metal code letter, and were exposed using a dental x-ray unit. Five measurements of radiographic density were obtained from each image of each item assessed (restorative material, enamel, dentin, each step of the aluminum step wedge) and the mean of these values was calculated. Radiopacity values were subsequently calculated as equivalents of aluminum thickness. Analysis of variance (ANOVA) indicated significant differences in radiopacity values among the materials (P<0.0001). The radiopacity values of the restorative materials evaluated were, in decreasing order: TPH, F2000, Synergy, Prisma Flow, Degufill, Luxat. Only Luxat had significantly lower radiopacity values than dentin. One material (Degufill) had similar radiopacity values to enamel and four (TPH, F2000, Synergy and Prisma Flow) had significantly higher radiopacity values than enamel. In conclusion, to assess the adequacy of posterior composite restorations it is important that the restorative material to be used has enough radiopacity, in order to be easily distinguished from the tooth structure in the radiographic image. Knowledge on the radiopacity of different materials helps professionals to select the most suitable material, along with other properties such as biocompatibility, adhesion and

  11. [Development of a digital EEG signal acquiring system based on virtual instrument technology].

    PubMed

    Ying, Jun; Chen, Guang-Fei; He, Shi-Lin

    2009-09-01

    This paper introduces an 16-lead digital EEG signal acquisition system, which applies MCU MSP430 as central control unit with high performance analog devices and high speed multi-channel, multi-bit analog-to-digital converter as peripheral to retrench analog circuit. Data is transferred to PC by USART interface. Software on PC based on virtual instrument technology realizes real-time detection, display and storage. The system has many advantages such as high precision, stable performance, small volume and low power dissipation, thus provides a new means for digital EEG signal acquisition. PMID:20073237

  12. Digital document imaging systems: An overview and guide

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This is an aid to NASA managers in planning the selection of a Digital Document Imaging System (DDIS) as a possible solution for document information processing and storage. Intended to serve as a manager's guide, this document contains basic information on digital imaging systems, technology, equipment standards, issues of interoperability and interconnectivity, and issues related to selecting appropriate imaging equipment based upon well defined needs.

  13. Digital Image Correlation for Performance Monitoring

    NASA Technical Reports Server (NTRS)

    Palaviccini, Miguel; Turner, Dan; Herzberg, Michael

    2016-01-01

    Evaluating the health of a mechanism requires more than just a binary evaluation of whether an operation was completed. It requires analyzing more comprehensive, full-field data. Health monitoring is a process of non-destructively identifying characteristics that indicate the fitness of an engineered component. In order to monitor unit health in a production setting, an automated test system must be created to capture the motion of mechanism parts in a real-time and non-intrusive manner. One way to accomplish this is by using high-speed video and Digital Image Correlation (DIC). In this approach, individual frames of the video are analyzed to track the motion of mechanism components. The derived performance metrics allow for state-of-health monitoring and improved fidelity of mechanism modeling. The results are in-situ state-of-health identification and performance prediction. This paper introduces basic concepts of this test method, and discusses two main themes: the use of laser marking to add fiducial patterns to mechanism components, and new software developed to track objects with complex shapes, even as they move behind obstructions. Finally, the implementation of these tests into an automated tester is discussed.

  14. Applications of digital image acquisition in anthropometry

    NASA Technical Reports Server (NTRS)

    Woolford, B.; Lewis, J. L.

    1981-01-01

    A description is given of a video kinesimeter, a device for the automatic real-time collection of kinematic and dynamic data. Based on the detection of a single bright spot by three TV cameras, the system provides automatic real-time recording of three-dimensional position and force data. It comprises three cameras, two incandescent lights, a voltage comparator circuit, a central control unit, and a mass storage device. The control unit determines the signal threshold for each camera before testing, sequences the lights, synchronizes and analyzes the scan voltages from the three cameras, digitizes force from a dynamometer, and codes the data for transmission to a floppy disk for recording. Two of the three cameras face each other along the 'X' axis; the third camera, which faces the center of the line between the first two, defines the 'Y' axis. An image from the 'Y' camera and either 'X' camera is necessary for determining the three-dimensional coordinates of the point.

  15. Copy-move forgery detection in digital image

    NASA Astrophysics Data System (ADS)

    Alamro, Loai; Yusoff, Nooraini

    2016-08-01

    Copy-move is considered as one of the most popular kind of digital image tempering, in which one or more parts of a digital image are copied and pasted into different locations. Geometric transformation is among the major challenges in detecting copy-move forgery of a digital image. In such forgery, the copied and moved parts of a forged image are either rotated or/and re-scaled. Hence, in this study we propose a combination of Discrete Wavelet Transform (DWT) and Speeded Up Robust Features (SURF) to detect a copy-move activity. The experiments results prove that the proposed method is superior with overall accuracy 95%. The copy-move attacks in digital image has been successfully detected and the method is also can detect the fraud parts exposed to rotation and scaling issue.

  16. Acquisition and evaluation of radiography images by digital camera.

    PubMed

    Cone, Stephen W; Carucci, Laura R; Yu, Jinxing; Rafiq, Azhar; Doarn, Charles R; Merrell, Ronald C

    2005-04-01

    To determine applicability of low-cost digital imaging for different radiographic modalities used in consultations from remote areas of the Ecuadorian rainforest with limited resources, both medical and financial. Low-cost digital imaging, consisting of hand-held digital cameras, was used for image capture at a remote location. Diagnostic radiographic images were captured in Ecuador by digital camera and transmitted to a password-protected File Transfer Protocol (FTP) server at VCU Medical Center in Richmond, Virginia, using standard Internet connectivity with standard security. After capture and subsequent transfer of images via low-bandwidth Internet connections, attending radiologists in the United States compared diagnoses to those from Ecuador to evaluate quality of image transfer. Corroborative diagnoses were obtained with the digital camera images for greater than 90% of the plain film and computed tomography studies. Ultrasound (U/S) studies demonstrated only 56% corroboration. Images of radiographs captured utilizing commercially available digital cameras can provide quality sufficient for expert consultation for many plain film studies for remote, underserved areas without access to advanced modalities.

  17. Invited article: Digital beam-forming imaging riometer systems.

    PubMed

    Honary, Farideh; Marple, Steve R; Barratt, Keith; Chapman, Peter; Grill, Martin; Nielsen, Erling

    2011-03-01

    The design and operation of a new generation of digital imaging riometer systems developed by Lancaster University are presented. In the heart of the digital imaging riometer is a field-programmable gate array (FPGA), which is used for the digital signal processing and digital beam forming, completely replacing the analog Butler matrices which have been used in previous designs. The reconfigurable nature of the FPGA has been exploited to produce tools for remote system testing and diagnosis which have proven extremely useful for operation in remote locations such as the Arctic and Antarctic. Different FPGA programs enable different instrument configurations, including a 4 × 4 antenna filled array (producing 4 × 4 beams), an 8 × 8 antenna filled array (producing 7 × 7 beams), and a Mills cross system utilizing 63 antennas producing 556 usable beams. The concept of using a Mills cross antenna array for riometry has been successfully demonstrated for the first time. The digital beam forming has been validated by comparing the received signal power from cosmic radio sources with results predicted from the theoretical beam radiation pattern. The performances of four digital imaging riometer systems are compared against each other and a traditional imaging riometer utilizing analog Butler matrices. The comparison shows that digital imaging riometer systems, with independent receivers for each antenna, can obtain much better measurement precision for filled arrays or much higher spatial resolution for the Mills cross configuration when compared to existing imaging riometer systems.

  18. Invited Article: Digital beam-forming imaging riometer systems

    NASA Astrophysics Data System (ADS)

    Honary, Farideh; Marple, Steve R.; Barratt, Keith; Chapman, Peter; Grill, Martin; Nielsen, Erling

    2011-03-01

    The design and operation of a new generation of digital imaging riometer systems developed by Lancaster University are presented. In the heart of the digital imaging riometer is a field-programmable gate array (FPGA), which is used for the digital signal processing and digital beam forming, completely replacing the analog Butler matrices which have been used in previous designs. The reconfigurable nature of the FPGA has been exploited to produce tools for remote system testing and diagnosis which have proven extremely useful for operation in remote locations such as the Arctic and Antarctic. Different FPGA programs enable different instrument configurations, including a 4 × 4 antenna filled array (producing 4 × 4 beams), an 8 × 8 antenna filled array (producing 7 × 7 beams), and a Mills cross system utilizing 63 antennas producing 556 usable beams. The concept of using a Mills cross antenna array for riometry has been successfully demonstrated for the first time. The digital beam forming has been validated by comparing the received signal power from cosmic radio sources with results predicted from the theoretical beam radiation pattern. The performances of four digital imaging riometer systems are compared against each other and a traditional imaging riometer utilizing analog Butler matrices. The comparison shows that digital imaging riometer systems, with independent receivers for each antenna, can obtain much better measurement precision for filled arrays or much higher spatial resolution for the Mills cross configuration when compared to existing imaging riometer systems.

  19. Image gathering and coding for digital restoration: Information efficiency and visual quality

    NASA Technical Reports Server (NTRS)

    Huck, Friedrich O.; John, Sarah; Mccormick, Judith A.; Narayanswamy, Ramkumar

    1989-01-01

    Image gathering and coding are commonly treated as tasks separate from each other and from the digital processing used to restore and enhance the images. The goal is to develop a method that allows us to assess quantitatively the combined performance of image gathering and coding for the digital restoration of images with high visual quality. Digital restoration is often interactive because visual quality depends on perceptual rather than mathematical considerations, and these considerations vary with the target, the application, and the observer. The approach is based on the theoretical treatment of image gathering as a communication channel (J. Opt. Soc. Am. A2, 1644(1985);5,285(1988). Initial results suggest that the practical upper limit of the information contained in the acquired image data range typically from approximately 2 to 4 binary information units (bifs) per sample, depending on the design of the image-gathering system. The associated information efficiency of the transmitted data (i.e., the ratio of information over data) ranges typically from approximately 0.3 to 0.5 bif per bit without coding to approximately 0.5 to 0.9 bif per bit with lossless predictive compression and Huffman coding. The visual quality that can be attained with interactive image restoration improves perceptibly as the available information increases to approximately 3 bifs per sample. However, the perceptual improvements that can be attained with further increases in information are very subtle and depend on the target and the desired enhancement.

  20. Semi-automatic registration of digital histopathology images to in-vivo MR images in molded and unmolded prostates

    PubMed Central

    Starobinets, Olga; Guo, Richard; Simko, Jeffry P.; Kuchinsky, Kyle; Kurhanewicz, John; Carroll, Peter R.; Greene, Kirsten L.; Noworolski, Susan M.

    2013-01-01

    Purpose To evaluate a semi-automatic software-based method of registering in vivo prostate magnetic resonance (MR) images to digital histopathology images using two approaches: 1) in which the prostates were molded to simulate distortion due to the endorectal imaging coil prior to fixation, and 2) in which the prostates were not molded. Materials and Methods T2-weighted MR images and digitized whole-mount histopathology images were acquired for twenty-six patients with biopsy-confirmed prostate cancer who underwent radical prostatectomy. Ten excised prostates were molded prior to fixation. A semi-automatic method was used to align MR images to histopathology. Percent overlap between MR and histopathology images, as well as distances between corresponding anatomical landmarks were calculated and used to evaluate the registration technique for molded and unmolded cases. Results The software successfully morphed histology-based prostate images into corresponding MR images. Percent overlap improved from 80.4±5.8% prior to morphing to 99.7±0.62% post morphing. Molded prostates had a smaller distance between landmarks (1.91±0.75mm) versus unmolded (2.34±0.68mm), p<0.08. Conclusion Molding a prostate prior to fixation provided a better alignment of internal structures within the prostate, but this did not reach statistical significance. Software-based morphing allowed for nearly complete overlap between the pathology slides and the MR images. PMID:24136783

  1. Multispectral Digital Image Analysis of Varved Sediments in Thin Sections

    NASA Astrophysics Data System (ADS)

    Jäger, K.; Rein, B.; Dietrich, S.

    2006-12-01

    An update of the recently developed method COMPONENTS (Rein, 2003, Rein & Jäger, subm.) for the discrimination of sediment components in thin sections is presented here. COMPONENTS uses a 6-band (multispectral) image analysis. To derive six-band spectral information of the sediments, thin sections are scanned with a digital camera mounted on a polarizing microscope. The thin sections are scanned twice, under polarized and under unpolarized plain light. During each run RGB images are acquired which are subsequently stacked to a six-band file. The first three bands (Blue=1, Green=2, Red=3) result from the spectral behaviour in the blue, green and red band with unpolarized light conditions, and the bands 4 to 6 (Blue=4, Green=5, Red=6) from the polarized light run. The next step is the discrimination of the sediment components by their transmission behaviour. Automatic classification algorithms broadly used in remote sensing applications cannot be used due to unavoidable variations of sediment particle or thin section thicknesses that change absolute grey values of the sediment components. Thus, we use an approach based on band ratios, also known as indices. By using band ratios, the grey values measured in different bands are normalized against each other and illumination variations (e.g. thickness variations) are eliminated. By combining specific ratios we are able to detect all seven major components in the investigated sediments (carbonates, diatoms, fine clastic material, plant rests, pyrite, quartz and resin). Then, the classification results (compositional maps) are validated. Although the automatic classification and the analogous classification show high concordances, some systematic errors could be identified. For example, the transition zone between the sediment and resin filled cracks is classified as fine clastic material and very coarse carbonates are partly classified as quartz because coarse carbonates can be very bright and spectra are partly

  2. Venus Atmospheric Circulation from Digital Tracking of VMC Images

    NASA Astrophysics Data System (ADS)

    Limaye, S.; Moissl, R.; Markiewicz, W.; Titov, D.

    2008-09-01

    The Venus Monitoring Camera on Venus Express has been returning images of Venus in four filters since April 2006 on almost every orbit. These images portray the southern hemisphere of Venus at spatial resolutions ranging from ~ 50 km per pixel to better than ~ 10 km per pixel depending on when the planet was imaged from orbit. Images covering a substantial portion of the planet and separated by ~ 45 min to one hour have been mapped into rectilinear projection to enable use of digital tracking technique for the measurement of cloud motions on an orbit by orbit basis. The aggregate results are in good agreement with visual tracking results as well as from the previous missions [1] and show evidence of temporal variations, large scale waves and solar thermal tides in low and mid latitudes. The digital tracking results for the meridional component confirm the poleward flow increasing from low latitudes to mid-latitudes and then showing a tendency to weaken. However, the confidence in high latitude measurements is lower due to the peculiar nature of the cloud morphology that is generally streaky and quite different from the low latitudes. The meridional profile of the average zonal wind at higher latitudes is of considerable interest. At high and polar latitudes, a vortex organization is evident in the data consistently, with the core region centered over the pole. The images show variability in structure of the ultraviolet signature of the "S" shaped feature seen in the VIRTIS data on the capture orbit [2]. However, the cloud morphologies seen poleward of ~ 50 degrees latitude also makes digital tracking less reliable due to absence of discrete features at the spatial resolution of the VMC images acquired in the apoapsis portion of the Venus Express orbit. It is expected that images obtained closer to the planet will enable a determination of the zonal wind profile with better confidence which will be useful in elucidating the nature of the transient features seen in

  3. Experiences with digital processing of images at INPE

    NASA Technical Reports Server (NTRS)

    Mascarenhas, N. D. A. (Principal Investigator)

    1984-01-01

    Four different research experiments with digital image processing at INPE will be described: (1) edge detection by hypothesis testing; (2) image interpolation by finite impulse response filters; (3) spatial feature extraction methods in multispectral classification; and (4) translational image registration by sequential tests of hypotheses.

  4. Precision Agriculture: Using Low-Cost Systems to Acquire Low-Altitude Images.

    PubMed

    Ponti, Moacir; Chaves, Arthur A; Jorge, Fabio R; Costa, Gabriel B P; Colturato, Adimara; Branco, Kalinka R L J C

    2016-01-01

    Low cost remote sensing imagery has the potential to make precision farming feasible in developing countries. In this article, the authors describe image acquisition from eucalyptus, bean, and sugarcane crops acquired by low-cost and low-altitude systems. They use different approaches to handle low-altitude images in both the RGB and NIR (near-infrared) bands to estimate and quantify plantation areas. PMID:27514030

  5. Precision Agriculture: Using Low-Cost Systems to Acquire Low-Altitude Images.

    PubMed

    Ponti, Moacir; Chaves, Arthur A; Jorge, Fabio R; Costa, Gabriel B P; Colturato, Adimara; Branco, Kalinka R L J C

    2016-01-01

    Low cost remote sensing imagery has the potential to make precision farming feasible in developing countries. In this article, the authors describe image acquisition from eucalyptus, bean, and sugarcane crops acquired by low-cost and low-altitude systems. They use different approaches to handle low-altitude images in both the RGB and NIR (near-infrared) bands to estimate and quantify plantation areas.

  6. The Reduction Of Motion Artifacts In Digital Subtraction Angiography By Geometrical Image Transformation

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, J. Michael; Pickens, David R.; Mandava, Venkateswara R.; Grefenstette, John J.

    1988-06-01

    In the diagnosis of arteriosclerosis, radio-opaque dye is injected into the interior of the arteries to make them visible. Because of its increased contrast sensitivity, digital subtraction angiography has the potential for providing diagnostic images of arteries with reduced dye volumes. In the conventional technique, a mask image, acquired before the introduction of the dye, is subtracted from the contrast image, acquired after the dye is introduced, to produce a difference image in which only the dye in the arteries is visible. The usefulness of this technique has been severely limited by the image degradation caused by patient motion during image acquisition. This motion produces artifacts in the difference image that obscure the arteries. One technique for dealing with this problem is to reduce the degradation by means of image registration. The registration is carried out by means of a geometrical transformation of the mask image before subtraction so that it is in registration with the contrast image. This paper describes our technique for determining an optimal transformation. We employ a one-to-one elastic mapping and the Jacobian of that mapping to produce a geometrical image transformation. We choose a parameterized class of such mappings and use a heuristic search algorithm to optimize the parameters to minimize the severity of the motion artifacts. To increase the speed of the optimization process we use a statistical image comparison technique that provides a quick approximate evaluation of each image transformation. We present the experimental results of the application of our registration system to mask-contrast pairs, for images acquired from a specially designed phantom (described in a companion paper), and for clinical images.

  7. Affordable, Accessible, Immediate: Capture Stunning Images with Digital Infrared Photography

    ERIC Educational Resources Information Center

    Snyder, Mark

    2011-01-01

    Technology educators who teach digital photography should consider incorporating an infrared (IR) photography component into their program. This is an area where digital photography offers significant benefits. Either type of IR imaging is very interesting to explore, but traditional film-based IR photography is difficult and expensive. In…

  8. The British Library Initiatives for Access Seminar: Digital Imaging.

    ERIC Educational Resources Information Center

    Alexander, Michael

    1996-01-01

    Provides an overview of the British Library's Initiatives for Access program which uses digital imaging. Highlights include digitization of microfilm, the electronic "Beowulf", electronic photographic viewing system, computer software that uses neural networks and fuzzy matching to provide links to search terms, and international projects. (LRW)

  9. Information Seeking Behavior in Digital Image Collections: A Cognitive Approach

    ERIC Educational Resources Information Center

    Matusiak, Krystyna K.

    2006-01-01

    Presents the results of a qualitative study that focuses on search patterns of college students and community users interacting with a digital image collection. The study finds a distinct difference between the two groups of users and examines the role of mental models in information seeking behavior in digital libraries.

  10. NEQR: a novel enhanced quantum representation of digital images

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Lu, Kai; Gao, Yinghui; Wang, Mo

    2013-08-01

    Quantum computation is becoming an important and effective tool to overcome the high real-time computational requirements of classical digital image processing. In this paper, based on analysis of existing quantum image representations, a novel enhanced quantum representation (NEQR) for digital images is proposed, which improves the latest flexible representation of quantum images (FRQI). The newly proposed quantum image representation uses the basis state of a qubit sequence to store the gray-scale value of each pixel in the image for the first time, instead of the probability amplitude of a qubit, as in FRQI. Because different basis states of qubit sequence are orthogonal, different gray scales in the NEQR quantum image can be distinguished. Performance comparisons with FRQI reveal that NEQR can achieve a quadratic speedup in quantum image preparation, increase the compression ratio of quantum images by approximately 1.5X, and retrieve digital images from quantum images accurately. Meanwhile, more quantum image operations related to gray-scale information in the image can be performed conveniently based on NEQR, for example partial color operations and statistical color operations. Therefore, the proposed NEQR quantum image model is more flexible and better suited for quantum image representation than other models in the literature.

  11. Post-digital image processing based on microlens array

    NASA Astrophysics Data System (ADS)

    Shi, Chaiyuan; Xu, Feng

    2014-10-01

    Benefit from the attractive features such as compact volume, thin and lightweight, the imaging systems based on microlens array have become an active area of research. However, current imaging systems based on microlens array have insufficient imaging quality so that it cannot meet the practical requirements in most applications. As a result, the post-digital image processing for image reconstruction from the low-resolution sub-image sequence becomes particularly important. In general, the post-digital image processing mainly includes two parts: the accurate estimation of the motion parameters between the sub-image sequence and the reconstruction of high resolution image. In this paper, given the fact that the preprocessing of the unit image can make the edge of the reconstructed high-resolution image clearer, the low-resolution images are preprocessed before the post-digital image processing. Then, after the processing of the pixel rearrange method, a high-resolution image is obtained. From the result, we find that the edge of the reconstructed high-resolution image is clearer than that without preprocessing.

  12. Digital infrared thermal imaging following anterior cruciate ligament reconstruction.

    PubMed

    Barker, Lauren E; Markowski, Alycia M; Henneman, Kimberly

    2012-03-01

    This case describes the selective use of digital infrared thermal imaging for a 48-year-old woman who was being treated by a physical therapist following left anterior cruciate ligament (ACL) reconstruction with a semitendinosus autograft. PMID:22383168

  13. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-047). March 2005. AREA OF MAGNET REMOVAL, NORTHEAST QUADRANT, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  14. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-004). March 2005. ENTRY TO IGLOO, ILLUSTRATING THICKNESS OF IGLOO WALL, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  15. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-026). March 2005. MOUSE AT EAST TANGENT, LOOKING TOWARD EAST TANGENT, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  16. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-006). March 2005. JACKBOLTS BETWEEN MAGNET AND MAGNET FOUNDATION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  17. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-107). March 2005. NORTH FAN, FAN ROOM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  18. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-043). March 2005. MOUSE AT EAST TANGENT, PLUNGING MECHANISM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  19. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-082). June 2005. CEILING AND CRANE OF BUILDING 51A, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  20. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-052). March 2005. LOCAL INJECTOR, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  1. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-106). March 2005. SOUTH FAN, FAN ROOM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  2. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-005). March 2005. PASSAGEWAY UNDER SOUTHEAST QUADRANT, AIR DUCT OPENINGS, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  3. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-015). March 2005. INTERIOR WALL OF MAGNET INSIDE CENTER OF BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  4. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-066). March 2005. LOCAL INJECTOR, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  5. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-108). March 2005. FAN ROOM WITH STAIR TO FILTER BANKS, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  6. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-050). March 2005. DIFFUSION PUMPS UNDER WEST TANGENT, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  7. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-077). March 2005. STUB OF SUPERHILAC BEAM, ENTERING SHIELDING, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  8. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-087). March 2005. GENERATOR PIT AREA, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  9. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection XBD200503-00117-089). March 2005. GENERATOR PIT AREA, CONCRETE FOUNDATION FOR EQUIPMENT MOUNTS, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  10. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-054). March 2005. LOCAL INJECTOR ENTERING SHIELDING, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  11. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-158). March 2005. CONNECTION OF MAGNET ROOM CRANE TO OUTER TRACK, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  12. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-012). March 2005. PASSAGEWAY UNDER QUADRANT AND DIFFUSION PUMPS, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  13. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-110). March 2005. SOUTH FAN FROM MEZZANINE, FAN ROOM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  14. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-143). March 2005. BUILDING 51A, EXTERIOR WALL, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  15. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-027). March 2005. MOUSE AT EAST TANGENT, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  16. Building Access for Digital Images: Databases, Meta-data, Interfaces.

    ERIC Educational Resources Information Center

    Smith, Steven D.

    1999-01-01

    When providing access to digital images, there are three elements to consider: structure, location, and appearance. These considerations are illustrated with two examples--a book and a photograph collection. Each of the elements is then described in detail. (AEF)

  17. Seeking the Green Basilisk Lizard: Acquiring Digital Literacy Practices in the Home

    ERIC Educational Resources Information Center

    Davidson, Christina

    2012-01-01

    Research confirms that young children engage in digital literacy practices in the home. While there is an emerging body of work that documents the diversity of these practices, there is little research that examines their acquisition in situ. This article uses conversation analysis to describe and explicate the social accomplishment of a number of…

  18. Digital image processing of bone - Problems and potentials

    NASA Technical Reports Server (NTRS)

    Morey, E. R.; Wronski, T. J.

    1980-01-01

    The development of a digital image processing system for bone histomorphometry and fluorescent marker monitoring is discussed. The system in question is capable of making measurements of UV or light microscope features on a video screen with either video or computer-generated images, and comprises a microscope, low-light-level video camera, video digitizer and display terminal, color monitor, and PDP 11/34 computer. Capabilities demonstrated in the analysis of an undecalcified rat tibia include the measurement of perimeter and total bone area, and the generation of microscope images, false color images, digitized images and contoured images for further analysis. Software development will be based on an existing software library, specifically the mini-VICAR system developed at JPL. It is noted that the potentials of the system in terms of speed and reliability far exceed any problems associated with hardware and software development.

  19. Taking digital imaging to the next level: challenges and opportunities.

    PubMed

    Hobbs, W Cecyl

    2004-01-01

    New medical imaging technology, such as multi-detector computed tomography (CT) scanners and positron emission tomography (PET) scanners, are creating new possibilities for non-invasive diagnosis that are leading providers to invest heavily in these new technologies. The volume of data produced by such technology is so large that it cannot be "read" using traditional film-based methods, and once in digital form, it creates a massive data integration and archiving challenge. Despite the benefits of digital imaging and archiving, there are several key challenges that healthcare organizations should consider in planning, selecting, and implementing the information technology (IT) infrastructure to support digital imaging. Decisions about storage and image distribution are essentially questions of "where" and "how fast." When planning the digital archiving infrastructure, organizations should think about where they want to store and distribute their images. This is similar to decisions that organizations have to make in regard to physical film storage and distribution, except the portability of images is even greater in a digital environment. The principle of "network effects" seems like a simple concept, yet the effect is not always considered when implementing a technology plan. To fully realize the benefits of digital imaging, the radiology department must integrate the archiving solutions throughout the department and, ultimately, with applications across other departments and enterprises. Medical institutions can derive a number of benefits from implementing digital imaging and archiving solutions like PACS. Hospitals and imaging centers can use the transition from film-based imaging as a foundational opportunity to reduce costs, increase competitive advantage, attract talent, and improve service to patients. The key factors in achieving these goals include attention to the means of data storage, distribution and protection. PMID:15098897

  20. Pollution prevention opportunity assessment for network operations` digital photo imagers

    SciTech Connect

    Phillips, N.M.

    1995-02-01

    This Pollution Prevention Opportunity Assessment (PPOA) was conducted to evaluate the operations of the digital photo imagers, which are located in Building 912, Room 097B and are used by Section 8910-1, Network Operations (in Department 8910, Infrastructure and Networking Research). This PPOA documents the processes, identifies the hazardous chemical waste streams generated by these processes, recommends possible ways to minimize waste, and serves as a reference for future assessments of the digital photo imaging process.

  1. Multimodal digital color imaging system for facial skin lesion analysis

    NASA Astrophysics Data System (ADS)

    Bae, Youngwoo; Lee, Youn-Heum; Jung, Byungjo

    2008-02-01

    In dermatology, various digital imaging modalities have been used as an important tool to quantitatively evaluate the treatment effect of skin lesions. Cross-polarization color image was used to evaluate skin chromophores (melanin and hemoglobin) information and parallel-polarization image to evaluate skin texture information. In addition, UV-A induced fluorescent image has been widely used to evaluate various skin conditions such as sebum, keratosis, sun damages, and vitiligo. In order to maximize the evaluation efficacy of various skin lesions, it is necessary to integrate various imaging modalities into an imaging system. In this study, we propose a multimodal digital color imaging system, which provides four different digital color images of standard color image, parallel and cross-polarization color image, and UV-A induced fluorescent color image. Herein, we describe the imaging system and present the examples of image analysis. By analyzing the color information and morphological features of facial skin lesions, we are able to comparably and simultaneously evaluate various skin lesions. In conclusion, we are sure that the multimodal color imaging system can be utilized as an important assistant tool in dermatology.

  2. Orthogonal rotation-invariant moments for digital image processing.

    PubMed

    Lin, Huibao; Si, Jennie; Abousleman, Glen P

    2008-03-01

    Orthogonal rotation-invariant moments (ORIMs), such as Zernike moments, are introduced and defined on a continuous unit disk and have been proven powerful tools in optics applications. These moments have also been digitized for applications in digital image processing. Unfortunately, digitization compromises the orthogonality of the moments and, therefore, digital ORIMs are incapable of representing subtle details in images and cannot accurately reconstruct images. Typical approaches to alleviate the digitization artifact can be divided into two categories: 1) careful selection of a set of pixels as close approximation to the unit disk and using numerical integration to determine the ORIM values, and 2) representing pixels using circular shapes such that they resemble that of the unit disk and then calculating ORIMs in polar space. These improvements still fall short of preserving the orthogonality of the ORIMs. In this paper, in contrast to the previous methods, we propose a different approach of using numerical optimization techniques to improve the orthogonality. We prove that with the improved orthogonality, image reconstruction becomes more accurate. Our simulation results also show that the optimized digital ORIMs can accurately reconstruct images and can represent subtle image details. PMID:18270118

  3. Topology-Preserving Rigid Transformation of 2D Digital Images.

    PubMed

    Ngo, Phuc; Passat, Nicolas; Kenmochi, Yukiko; Talbot, Hugues

    2014-02-01

    We provide conditions under which 2D digital images preserve their topological properties under rigid transformations. We consider the two most common digital topology models, namely dual adjacency and well-composedness. This paper leads to the proposal of optimal preprocessing strategies that ensure the topological invariance of images under arbitrary rigid transformations. These results and methods are proved to be valid for various kinds of images (binary, gray-level, label), thus providing generic and efficient tools, which can be used in particular in the context of image registration and warping.

  4. Topology-Preserving Rigid Transformation of 2D Digital Images.

    PubMed

    Ngo, Phuc; Passat, Nicolas; Kenmochi, Yukiko; Talbot, Hugues

    2014-02-01

    We provide conditions under which 2D digital images preserve their topological properties under rigid transformations. We consider the two most common digital topology models, namely dual adjacency and well-composedness. This paper leads to the proposal of optimal preprocessing strategies that ensure the topological invariance of images under arbitrary rigid transformations. These results and methods are proved to be valid for various kinds of images (binary, gray-level, label), thus providing generic and efficient tools, which can be used in particular in the context of image registration and warping. PMID:26270925

  5. Analysis of facial sebum distribution using a digital fluorescent imaging system.

    PubMed

    Han, Byungkwan; Jung, Byungjo; Nelson, J Stuart; Choi, Eung-Ho

    2007-01-01

    Current methods for analysis of sebum excretion have limitations, such as irreproducible results in repeatable measurements due to the point measurement method, user-dependent artifacts due to contact measurement or qualitative evaluation of the image, and long measurement time. A UV-induced fluorescent digital imaging system is developed to acquire facial images so that the distribution of sebum excretion on the face could be analyzed. The imaging system consists of a constant UV-A light source, digital color camera, and head-positioning device. The system for acquisition of a fluorescent facial image and the image analysis method is described. The imaging modality provides uniform light distribution and presents a discernible color fluorescent image. Valuable parameters of sebum excretion are obtained after image analysis. The imaging system, which provides a noncontact method, is proved to be a useful tool to evaluate the amount and pattern of sebum excretion. When compared to conventional "Wood's lamp" and "Sebutape" methods that provide similar parameters for sebum excretion, the described method is simpler and more reliable to evaluate the dynamics of sebum excretion in nearly real-time. PMID:17343481

  6. The influence of software filtering in digital mammography image quality

    NASA Astrophysics Data System (ADS)

    Michail, C.; Spyropoulou, V.; Kalyvas, N.; Valais, I.; Dimitropoulos, N.; Fountos, G.; Kandarakis, I.; Panayiotakis, G.

    2009-05-01

    Breast cancer is one of the most frequently diagnosed cancers among women. Several techniques have been developed to help in the early detection of breast cancer such as conventional and digital x-ray mammography, positron and single-photon emission mammography, etc. A key advantage in digital mammography is that images can be manipulated as simple computer image files. Thus non-dedicated commercially available image manipulation software can be employed to process and store the images. The image processing tools of the Photoshop (CS 2) software usually incorporate digital filters which may be used to reduce image noise, enhance contrast and increase spatial resolution. However, improving an image quality parameter may result in degradation of another. The aim of this work was to investigate the influence of three sharpening filters, named hereafter sharpen, sharpen more and sharpen edges on image resolution and noise. Image resolution was assessed by means of the Modulation Transfer Function (MTF).In conclusion it was found that the correct use of commercial non-dedicated software on digital mammograms may improve some aspects of image quality.

  7. [Spectral radiometric calibration research of Quick Bird digital image].

    PubMed

    Zhang, Guo-Kun; Chen, Chun; Xing, Fu; Zhang, Hong-Yan; Zhao, Yun-Sheng

    2008-03-01

    The present article uses the basic operation of the digital remote image radiometric calibration of the Quickbird with high distinguishing rate, including the physical attribute and the mathematical basement of digital images, the annotation as well as the format of image data. The study makes use of information of spectral radiance from the ground-atmosphere system, which is recorded by the digital remote image of Quick Bird in Honghe area. This dissertation offered the calculation means of radiometric calibration, and changed the pixel digital number into band-integrated radiance. Then, the spectral radiance was calculated. After the radiometric calibration, the Quick Bird image showed the quantitative information of spectral feature from various ground items. Only through the calibration can the Quick Bird image be quantitatively compared and analyzed with other remote sensor images. Thus, the inversion image has the value of application. The significance consists in offering important basic condition for the image amalgamation and better disposal of the special inforation pick-up. This effort also offered spectral information of the ground items for the inversion of the remote image. Therefore, the authors can combine the research of the spectral character of ground items with the establishment of the remote application model in order to quantitatively analyze the ground items.

  8. Quantitative evaluation of digital dental radiograph imaging systems.

    PubMed

    Hildebolt, C F; Vannier, M W; Pilgram, T K; Shrout, M K

    1990-11-01

    Two digital imaging systems, a video camera and analog-to-digital converter, and a charge-coupled device linear photodiode array slide scanner, were tested for their suitability in quantitative studies of periodontal disease. The information content in the original films was estimated, and digital systems were assessed according to these requirements. Radiometric and geometric performance criteria for the digital systems were estimated from measurements and observations. The scanner-based image acquisition (digitization) system had no detectable noise and had a modulation transfer function curve superior to that of the video-based system. The scanner-based system was equivalent to the video-based system in recording radiographic film densities and had more geometric distortion than the video-based system. The comparison demonstrated the superiority of the charge-coupled device linear array system for the quantification of periodontal disease extent and activity. PMID:2234888

  9. Wavelength scanning digital interference holography for high-resolution ophthalmic imaging

    NASA Astrophysics Data System (ADS)

    Potcoava, Mariana C.; Kim, M. K.; Kay, Christine N.

    2009-02-01

    An improved digital interference holography (DIH) technique suitable for fundus images is proposed. This technique incorporates a dispersion compensation algorithm to compensate for the unknown axial length of the eye. Using this instrument we acquired successfully tomographic fundus images in human eye with narrow axial resolution less than 5μm. The optic nerve head together with the surrounding retinal vasculature were constructed. We were able to quantify a depth of 84μm between the retinal fiber and the retinal pigmented epithelium layers. DIH provides high resolution 3D information which could potentially aid in guiding glaucoma diagnosis and treatment.

  10. Digital management and regulatory submission of medical images from clinical trials: role and benefits of the core laboratory

    NASA Astrophysics Data System (ADS)

    Robbins, William L.; Conklin, James J.

    1995-10-01

    Medical images (angiography, CT, MRI, nuclear medicine, ultrasound, x ray) play an increasingly important role in the clinical development and regulatory review process for pharmaceuticals and medical devices. Since medical images are increasingly acquired and archived digitally, or are readily digitized from film, they can be visualized, processed and analyzed in a variety of ways using digital image processing and display technology. Moreover, with image-based data management and data visualization tools, medical images can be electronically organized and submitted to the U.S. Food and Drug Administration (FDA) for review. The collection, processing, analysis, archival, and submission of medical images in a digital format versus an analog (film-based) format presents both challenges and opportunities for the clinical and regulatory information management specialist. The medical imaging 'core laboratory' is an important resource for clinical trials and regulatory submissions involving medical imaging data. Use of digital imaging technology within a core laboratory can increase efficiency and decrease overall costs in the image data management and regulatory review process.

  11. Ultra-high resolution color images of the surface of comet 67P acquired by ROLIS

    NASA Astrophysics Data System (ADS)

    Schröder, Stefan; Mottola, Stefano; Arnold, Gabriele; Grothues, Hans-Georg; Hamm, Maximilian; Jaumann, Ralf; Michaelis, Harald; Pelivan, Ivanka; Proffe, Gerrit; Bibring, Jean-Pierre

    2015-04-01

    On Nov 12, 2014, the Rosetta Philae lander descended towards comet 67P/Churyumov-Gerasimenko. The onboard ROLIS camera successfully acquired high resolution images of the surface looking down from its vantage point on the instrument platform. ROLIS is a compact CCD imager with a 1024×1024 pixel sensor and a 57° field of view (Mottola et al., 2007, SSR 128, 241). It is equipped with an infinity lens (IFL), without which the camera focus is 30 cm. At Philae's final landing site, ROLIS removed the IFL and initiated an imaging sequence that shows the surface at the highest resolution ever obtained for a cometary surface (~0.5 mm per pixel). Illumination of the scene was provided by an onboard array of LEDs in four different colors: red, green, blue, and near-IR. ROLIS acquired one image for each color and a single dark exposure. The images show a unique, almost fractal morphology for the surface below the landing site that defies easy interpretation. However, there are similarities with some structures seen by the CIVA camera. Color and albedo variations over the surface are minor, and individual grains cannot be distinguished. The images are out-of-focus, indicating the surface was further away than the nominal 30 cm. The location of the illumination spot and the change of focus over the image are consistent with an inclined surface, indicating that Philae's final resting position is strongly tilted. In fact, it was inclined so much that we see the local horizon, even though ROLIS is downward-looking. Remarkably, the scene beyond the horizon is illuminated by the Sun, and out-of-focus particles can be seen to travel in the sky. The images suggest the environment of the lander is laden with fine dust, but a final assessment requires careful consideration of possible sources of stray light. Just before Philae went to sleep, ROLIS acquired an additional exposure with the IFL and the red LED. The resulting image is fully in focus. Because Philae had rotated and lifted

  12. Marking-dots digital image correlation and application to studies of spinal biomechanics

    NASA Astrophysics Data System (ADS)

    Chen, Jinlong; Sun, Cuiru; Qin, Yuwen; Ji, Xinhua

    2005-04-01

    A method of marking-dots digital image correlation is developed to measure the biomechanics behavior of cattle spine. In the system, a video camera and personal computer are used to acquire digitized images of a random speckle pattern on the surface of a marking-dot before and after deformation. The method of making-dots digital image correlation can immediately measure the transformation by tracking the gray value pattern in small local neighborhoods commonly referred to as subsets. In the experiment, a specimen was selected from the cattle's spine that was covered with some muscles and tissues. It is apparent that the covering muscles and tissues cannot be treated as the information carrier, for they must be kept active and moist curing by the physiological brine in the course of the experiment. In order to solve the problem, the marking-dots were fixed into the vertebrae, and the front surface of a marking-dot was coated with a thin layer of white paint and splattered with black spot so as to create a random black-on-white speckle pattern. Experimental results have shown that the marking-dots digital image correlation method can be applied to the measurement of the biomechanical behavior of cattle spine, and offer an effective measurement tool to research the range of motion of the adjacent segment in spine under intervertebral fusion.

  13. A procedure for detection and measurement of interfaces in remotely acquired data using a digital computer

    NASA Technical Reports Server (NTRS)

    Faller, K. H.

    1977-01-01

    A technique developed and evaluated for the detection and measurement of surface feature interfaces in remotely acquired data is described. A computer implementation of this technique has been effected to automatically process categorized data derived from various sources such as the LANDSAT multispectral scanner and other scanner type sensors. The basic elements of the operational theory of the technique are described together with details of the procedure. An example application of the technique to the analysis of tidal shoreline length is given with a breakdown of manpower requirements.

  14. Procedure for detection and measurement of interfaces in remotely acquired data using a digital computer

    NASA Technical Reports Server (NTRS)

    Faller, K. H.

    1976-01-01

    A technique for the detection and measurement of surface feature interfaces in remotely acquired data was developed and evaluated. A computer implementation of this technique was effected to automatically process classified data derived from various sources such as the LANDSAT multispectral scanner and other scanning sensors. The basic elements of the operational theory of the technique are described, followed by the details of the procedure. An example of an application of the technique to the analysis of tidal shoreline length is given with a breakdown of manpower requirements.

  15. Imaging the urokinase plasminongen activator receptor in preclinical breast cancer models of acquired drug resistance.

    PubMed

    LeBeau, Aaron M; Sevillano, Natalia; King, Mandy L; Duriseti, Sai; Murphy, Stephanie T; Craik, Charles S; Murphy, Laura L; VanBrocklin, Henry F

    2014-01-01

    Subtype-targeted therapies can have a dramatic impact on improving the quality and quantity of life for women suffering from breast cancer. Despite an initial therapeutic response, cancer recurrence and acquired drug-resistance are commonplace. Non-invasive imaging probes that identify drug-resistant lesions are urgently needed to aid in the development of novel drugs and the effective utilization of established therapies for breast cancer. The protease receptor urokinase plasminogen activator receptor (uPAR) is a target that can be exploited for non-invasive imaging. The expression of uPAR has been associated with phenotypically aggressive breast cancer and acquired drug-resistance. Acquired drug-resistance was modeled in cell lines from two different breast cancer subtypes, the uPAR negative luminal A subtype and the uPAR positive triple negative subtype cell line MDA-MB-231. MCF-7 cells, cultured to be resistant to tamoxifen (MCF-7 TamR), were found to significantly over-express uPAR compared to the parental cell line. uPAR expression was maintained when resistance was modeled in triple-negative breast cancer by generating doxorubicin and paclitaxel resistant MDA-MB-231 cells (MDA-MB-231 DoxR and MDA-MB-231 TaxR). Using the antagonistic uPAR antibody 2G10, uPAR was imaged in vivo by near-infrared (NIR) optical imaging and (111)In-single photon emission computed tomography (SPECT). Tumor uptake of the (111)In-SPECT probe was high in the three drug-resistant xenografts (> 46 %ID/g) and minimal in uPAR negative xenografts at 72 hours post-injection. This preclinical study demonstrates that uPAR can be targeted for imaging breast cancer models of acquired resistance leading to potential clinical applications. PMID:24505235

  16. A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging

    PubMed Central

    Gallio, Elena; Rampado, Osvaldo; Gianaria, Elena; Bianchi, Silvio Diego; Ropolo, Roberto

    2015-01-01

    Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies. PMID:26545097

  17. A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging.

    PubMed

    Gallio, Elena; Rampado, Osvaldo; Gianaria, Elena; Bianchi, Silvio Diego; Ropolo, Roberto

    2015-01-01

    Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies. PMID:26545097

  18. A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging.

    PubMed

    Gallio, Elena; Rampado, Osvaldo; Gianaria, Elena; Bianchi, Silvio Diego; Ropolo, Roberto

    2015-01-01

    Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies.

  19. Automatic Rice Crop Height Measurement Using a Field Server and Digital Image Processing

    PubMed Central

    Sritarapipat, Tanakorn; Rakwatin, Preesan; Kasetkasem, Teerasit

    2014-01-01

    Rice crop height is an important agronomic trait linked to plant type and yield potential. This research developed an automatic image processing technique to detect rice crop height based on images taken by a digital camera attached to a field server. The camera acquires rice paddy images daily at a consistent time of day. The images include the rice plants and a marker bar used to provide a height reference. The rice crop height can be indirectly measured from the images by measuring the height of the marker bar compared to the height of the initial marker bar. Four digital image processing steps are employed to automatically measure the rice crop height: band selection, filtering, thresholding, and height measurement. Band selection is used to remove redundant features. Filtering extracts significant features of the marker bar. The thresholding method is applied to separate objects and boundaries of the marker bar versus other areas. The marker bar is detected and compared with the initial marker bar to measure the rice crop height. Our experiment used a field server with a digital camera to continuously monitor a rice field located in Suphanburi Province, Thailand. The experimental results show that the proposed method measures rice crop height effectively, with no human intervention required. PMID:24451465

  20. Resolution enhancement phase-contrast imaging by microsphere digital holography

    NASA Astrophysics Data System (ADS)

    Wang, Yunxin; Guo, Sha; Wang, Dayong; Lin, Qiaowen; Rong, Lu; Zhao, Jie

    2016-05-01

    Microsphere has shown the superiority of super-resolution imaging in the traditional 2D intensity microscope. Here a microsphere digital holography approach is presented to realize the resolution enhancement phase-contrast imaging. The system is designed by combining the microsphere with the image-plane digital holography. A microsphere very close to the object can increase the resolution by transforming the object wave from the higher frequency to the lower one. The resolution enhancement amplitude and phase images can be retrieved from a single hologram. The experiments are carried on the 1D and 2D gratings, and the results demonstrate that the observed resolution has been improved, meanwhile, the phase-contrast image is obtained. The proposed method can improve the transverse resolution in all directions based on a single exposure. Furthermore, this system has extended the application of the microsphere from the conventional 2D microscopic imaging to 3D phase-contrast microscopic imaging.

  1. TM digital image products for applications. [computer compatible tapes

    NASA Technical Reports Server (NTRS)

    Barker, J. L.; Gunther, F. J.; Abrams, R. B.; Ball, D.

    1984-01-01

    The image characteristics of digital data generated by LANDSAT 4 thematic mapper (TM) are discussed. Digital data from the TM resides in tape files at various stages of image processing. Within each image data file, the image lines are blocked by a factor of either 5 for a computer compatible tape CCT-BT, or 4 for a CCT-AT and CCT-PT; in each format, the image file has a different format. Nominal geometric corrections which provide proper geodetic relationships between different parts of the image are available only for the CCT-PT. It is concluded that detector 3 of band 5 on the TM does not respond; this channel of data needs replacement. The empty bin phenomenon in CCT-AT images results from integer truncations of mixed-mode arithmetric operations.

  2. The comparative effectiveness of conventional and digital image libraries.

    PubMed

    McColl, R I; Johnson, A

    2001-03-01

    Before introducing a hospital-wide image database to improve access, navigation and retrieval speed, a comparative study between a conventional slide library and a matching image database was undertaken to assess its relative benefits. Paired time trials and personal questionnaires revealed faster retrieval rates, higher image quality, and easier viewing for the pilot digital image database. Analysis of confidentiality, copyright and data protection exposed similar issues for both systems, thus concluding that the digital image database is a more effective library system. The authors suggest that in the future, medical images will be stored on large, professionally administered, centrally located file servers, allowing specialist image libraries to be tailored locally for individual users. The further integration of the database with web technology will enable cheap and efficient remote access for a wide range of users.

  3. Digital Topology and Geometry in Medical Imaging: A Survey.

    PubMed

    Saha, Punam K; Strand, Robin; Borgefors, Gunilla

    2015-09-01

    Digital topology and geometry refers to the use of topologic and geometric properties and features for images defined in digital grids. Such methods have been widely used in many medical imaging applications, including image segmentation, visualization, manipulation, interpolation, registration, surface-tracking, object representation, correction, quantitative morphometry etc. Digital topology and geometry play important roles in medical imaging research by enriching the scope of target outcomes and by adding strong theoretical foundations with enhanced stability, fidelity, and efficiency. This paper presents a comprehensive yet compact survey on results, principles, and insights of methods related to digital topology and geometry with strong emphasis on understanding their roles in various medical imaging applications. Specifically, this paper reviews methods related to distance analysis and path propagation, connectivity, surface-tracking, image segmentation, boundary and centerline detection, topology preservation and local topological properties, skeletonization, and object representation, correction, and quantitative morphometry. A common thread among the topics reviewed in this paper is that their theory and algorithms use the principle of digital path connectivity, path propagation, and neighborhood analysis.

  4. Terahertz digital holography image processing based on MAP algorithm

    NASA Astrophysics Data System (ADS)

    Chen, Guang-Hao; Li, Qi

    2015-04-01

    Terahertz digital holography combines the terahertz technology and digital holography technology at present, fully exploits the advantages in both of them. Unfortunately, the quality of terahertz digital holography reconstruction images is gravely harmed by speckle noise which hinders the popularization of this technology. In this paper, the maximum a posterior estimation (MAP) filter is harnessed for the restoration of the digital reconstruction images. The filtering results are compared with images filtered by Wiener Filter and conventional frequency-domain filters from both subjective and objective perspectives. As for objective assessment, we adopted speckle index (SPKI) and edge preserving index (EPI) to quantitate the quality of images. In this paper, Canny edge detector is also used to outline the target in original and reconstruction images, which then act as an important role in the evaluation of filter performance. All the analysis indicate that maximum a posterior estimation filtering algorithm performs superiorly compared with the other two competitors in this paper and has enhanced the terahertz digital holography reconstruction images to a certain degree, allowing for a more accurate boundary identification.

  5. SU-E-J-186: Acquiring and Assessing Upright CBCT Images for Future Treatment Planning

    SciTech Connect

    Fave, X; Yang, J; Balter, P; Court, L

    2014-06-01

    Purpose: To acquire upright CBCT images using the onboard imager of a Varian TrueBeam. An easy to implement upright imaging protocol could allow for widespread upright radiation therapy which would greatly benefit certain patients. These include thoracic cancer patients (because lung volume increases in a seated position) and patients who experience substantial discomfort during supine treatment. Methods: To acquire upright CBCT images, the gantry head remained stationary at 0 degrees with the KV imager arms extended to their lateral positions. Phantoms were placed upright at the end of the treatment couch. During a scan, the couch rotated from 270 to 90 degrees while continuous fluoroscopic projections were taken by the onboard imager. To extend the field-of-view, this sequence was performed twice: once with the KV detector longitudinally offset +14.5cm and once with it longitudinally offset −14.5cm. The resulting two image sets were stitched together before reconstruction. The imaging beam parameters were chosen to deliver a dose similar to that given during a simulation CT. Image quality was evaluated for spatial linearity, high and low contrast resolution, and HU linearity using CatPhan and anthropomorphic phantoms. A deformable registration technique was used to evaluate HU mapping from a simulation CT. Results: Spatial linearity and high contrast resolution were maintained in upright CBCT when compared to simulation CT. However, low contrast resolution and HU linearity degraded. Streak artifacts were caused by the limited 180 degree arc of the couch, and the stitching process created a sharp artifact at the center of the reconstruction. The deformable registration was robust in the HU mapping even with these artifacts and the loss of HU linearity. Conclusions: The image quality obtained from upright CBCT was sufficient for treatment planning. The success of this novel technique is an important step towards a future clinical protocol. This project was funded

  6. The digital optical module - How IceCube will acquire data

    SciTech Connect

    Stokstad, R.G.

    2003-01-09

    IceCube will be a km-scale neutrino detector consisting of 4800 optical modules (OMs) on 80 strings of 60 OMs each. The DAQ technology will have the following desirable features: (1) the robustness of copper cable between the OMs and the surface. (2) digitization and time-stamping of signals that are unattenuated and undispersed. (3) calibration methods (particularly for timing) appropriate for a large number of OMs. The PMT anode waveform is digitized and time-stamped in the OM. The time calibration procedure is both accurate and automatic. A system having these features has been tested in AMANDA. A prototype digital system consisting of 40 OMs was deployed in Jan., 2000. The principal components of the Digital Optical Module (DOM) signal processing circuitry are: the analog transient waveform digitizer (ATWD), a low-power custom integrated circuit that captures the waveform in 128 samples at a rate of {approx}500 Megasamples/s; an ADC operating at {approx}30 MS/s covering several microseconds; a FPGA that provides state control, time stamps events, handles communications, etc.; a low-power 32-bit ARM CPU with a real-time operating system. A 16.8 MHz oscillator, made by Toyocom, is free-running, very stable ({delta}f/f {approx} 5 {center_dot} 10{sup -11} over {approx} 5s) and provides clock signals to several components. Short (12 m) cables connecting adjacent modules enable a local time coincidence, which eliminates most of the {approx}1 kHz of dark noise pulses. A critical requirement is the ability to calibrate the DOM oscillator against a master clock at the surface. In essence, timing pulses sent in one direction at known time intervals can be used to determine relative frequency, and the round trip time of pulses sent in both directions can determine the offset. After receiving a timing pulse at the DOM and waiting for a short time, {delta}t, measured on the DOM clock, a pulse is sent from the DOM to the surface. The shapes of the pulses sent down and up are

  7. The FBI compression standard for digitized fingerprint images

    SciTech Connect

    Brislawn, C.M.; Bradley, J.N.; Onyshczak, R.J.; Hopper, T.

    1996-10-01

    The FBI has formulated national standards for digitization and compression of gray-scale fingerprint images. The compression algorithm for the digitized images is based on adaptive uniform scalar quantization of a discrete wavelet transform subband decomposition, a technique referred to as the wavelet/scalar quantization method. The algorithm produces archival-quality images at compression ratios of around 15 to 1 and will allow the current database of paper fingerprint cards to be replaced by digital imagery. A compliance testing program is also being implemented to ensure high standards of image quality and interchangeability of data between different implementations. We will review the current status of the FBI standard, including the compliance testing process and the details of the first-generation encoder.

  8. Generation and Analysis of Wire Rope Digital Radiographic Images

    NASA Astrophysics Data System (ADS)

    Chakhlov, S.; Anpilogov, P.; Batranin, A.; Osipov, S.; Zhumabekova, Sh; Yadrenkin, I.

    2016-06-01

    The paper is dealt with different structures of the digital radiographic system intended for wire rope radiography. The scanning geometry of the wire rope is presented and the main stages of its digital radiographic image generation are identified herein. Correction algorithms are suggested for X-ray beam hardening. A complex internal structure of the wire rope is illustrated by its 25 mm diameter image obtained from X-ray computed tomography. The paper considers the approach to the analysis of digital radiographic image algorithms based on the closeness of certain parameters (invariants) of all unit cross-sections of the reference wire rope or its sections with the length equaling to the lay. The main invariants of wire rope radiographic images are identified and compared with its typical defects.

  9. Digital filter design for radar image formation

    NASA Technical Reports Server (NTRS)

    Adams, John W.; Nelson, Jeffrey E.; Banh, N. D.; Moncada, John J.; Bayma, Robert W.

    1989-01-01

    Novel weighted-least-squares approaches to the design of digital filters for SAR applications are presented. The filters belong to three different categories according to their combinations of minimax passband, least-squares stopband, minimax stopband, and maximally-flat passband. For real-time applications, it is important to design the sets of digital filter coefficient tables in an offline environment; the appropriate precomputed filter is then selected for each SAR signal-processing function, as a function of both mode and mapping geometry during real-time processing.

  10. Digital image compression for a 2f multiplexing optical setup

    NASA Astrophysics Data System (ADS)

    Vargas, J.; Amaya, D.; Rueda, E.

    2016-07-01

    In this work a virtual 2f multiplexing system was implemented in combination with digital image compression techniques and redundant information elimination. Depending on the image type to be multiplexed, a memory-usage saving of as much as 99% was obtained. The feasibility of the system was tested using three types of images, binary characters, QR codes, and grey level images. A multiplexing step was implemented digitally, while a demultiplexing step was implemented in a virtual 2f optical setup following real experimental parameters. To avoid cross-talk noise, each image was codified with a specially designed phase diffraction carrier that would allow the separation and relocation of the multiplexed images on the observation plane by simple light propagation. A description of the system is presented together with simulations that corroborate the method. The present work may allow future experimental implementations that will make use of all the parallel processing capabilities of optical systems.

  11. GEOMETRIC PROCESSING OF DIGITAL IMAGES OF THE PLANETS.

    USGS Publications Warehouse

    Edwards, Kathleen

    1987-01-01

    New procedures and software have been developed for geometric transformations of images to support digital cartography of the planets. The procedures involve the correction of spacecraft camera orientation of each image with the use of ground control and the transformation of each image to a Sinusoidal Equal-Area map projection with an algorithm which allows the number of transformation calculations to vary as the distortion varies within the image. When the distortion is low in an area of an image, few transformation computations are required, and most pixels can be interpolated. When distortion is extreme, the location of each pixel is computed. Mosaics are made of these images and stored as digital databases.

  12. Low-Light Image Enhancement Using Adaptive Digital Pixel Binning

    PubMed Central

    Yoo, Yoonjong; Im, Jaehyun; Paik, Joonki

    2015-01-01

    This paper presents an image enhancement algorithm for low-light scenes in an environment with insufficient illumination. Simple amplification of intensity exhibits various undesired artifacts: noise amplification, intensity saturation, and loss of resolution. In order to enhance low-light images without undesired artifacts, a novel digital binning algorithm is proposed that considers brightness, context, noise level, and anti-saturation of a local region in the image. The proposed algorithm does not require any modification of the image sensor or additional frame-memory; it needs only two line-memories in the image signal processor (ISP). Since the proposed algorithm does not use an iterative computation, it can be easily embedded in an existing digital camera ISP pipeline containing a high-resolution image sensor. PMID:26121609

  13. Low-Light Image Enhancement Using Adaptive Digital Pixel Binning.

    PubMed

    Yoo, Yoonjong; Im, Jaehyun; Paik, Joonki

    2015-01-01

    This paper presents an image enhancement algorithm for low-light scenes in an environment with insufficient illumination. Simple amplification of intensity exhibits various undesired artifacts: noise amplification, intensity saturation, and loss of resolution. In order to enhance low-light images without undesired artifacts, a novel digital binning algorithm is proposed that considers brightness, context, noise level, and anti-saturation of a local region in the image. The proposed algorithm does not require any modification of the image sensor or additional frame-memory; it needs only two line-memories in the image signal processor (ISP). Since the proposed algorithm does not use an iterative computation, it can be easily embedded in an existing digital camera ISP pipeline containing a high-resolution image sensor. PMID:26121609

  14. 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.

  15. Digital adaptive optics line-scanning confocal imaging system.

    PubMed

    Liu, Changgeng; Kim, Myung K

    2015-01-01

    A digital adaptive optics line-scanning confocal imaging (DAOLCI) system is proposed by applying digital holographic adaptive optics to a digital form of line-scanning confocal imaging system. In DAOLCI, each line scan is recorded by a digital hologram, which allows access to the complex optical field from one slice of the sample through digital holography. This complex optical field contains both the information of one slice of the sample and the optical aberration of the system, thus allowing us to compensate for the effect of the optical aberration, which can be sensed by a complex guide star hologram. After numerical aberration compensation, the corrected optical fields of a sequence of line scans are stitched into the final corrected confocal image. In DAOLCI, a numerical slit is applied to realize the confocality at the sensor end. The width of this slit can be adjusted to control the image contrast and speckle noise for scattering samples. DAOLCI dispenses with the hardware pieces, such as Shack–Hartmann wavefront sensor and deformable mirror, and the closed-loop feedbacks adopted in the conventional adaptive optics confocal imaging system, thus reducing the optomechanical complexity and cost. Numerical simulations and proof-of-principle experiments are presented that demonstrate the feasibility of this idea.

  16. Digital adaptive optics line-scanning confocal imaging system

    PubMed Central

    Liu, Changgeng; Kim, Myung K.

    2015-01-01

    Abstract. A digital adaptive optics line-scanning confocal imaging (DAOLCI) system is proposed by applying digital holographic adaptive optics to a digital form of line-scanning confocal imaging system. In DAOLCI, each line scan is recorded by a digital hologram, which allows access to the complex optical field from one slice of the sample through digital holography. This complex optical field contains both the information of one slice of the sample and the optical aberration of the system, thus allowing us to compensate for the effect of the optical aberration, which can be sensed by a complex guide star hologram. After numerical aberration compensation, the corrected optical fields of a sequence of line scans are stitched into the final corrected confocal image. In DAOLCI, a numerical slit is applied to realize the confocality at the sensor end. The width of this slit can be adjusted to control the image contrast and speckle noise for scattering samples. DAOLCI dispenses with the hardware pieces, such as Shack–Hartmann wavefront sensor and deformable mirror, and the closed-loop feedbacks adopted in the conventional adaptive optics confocal imaging system, thus reducing the optomechanical complexity and cost. Numerical simulations and proof-of-principle experiments are presented that demonstrate the feasibility of this idea. PMID:26140334

  17. Digital adaptive optics line-scanning confocal imaging system.

    PubMed

    Liu, Changgeng; Kim, Myung K

    2015-01-01

    A digital adaptive optics line-scanning confocal imaging (DAOLCI) system is proposed by applying digital holographic adaptive optics to a digital form of line-scanning confocal imaging system. In DAOLCI, each line scan is recorded by a digital hologram, which allows access to the complex optical field from one slice of the sample through digital holography. This complex optical field contains both the information of one slice of the sample and the optical aberration of the system, thus allowing us to compensate for the effect of the optical aberration, which can be sensed by a complex guide star hologram. After numerical aberration compensation, the corrected optical fields of a sequence of line scans are stitched into the final corrected confocal image. In DAOLCI, a numerical slit is applied to realize the confocality at the sensor end. The width of this slit can be adjusted to control the image contrast and speckle noise for scattering samples. DAOLCI dispenses with the hardware pieces, such as Shack–Hartmann wavefront sensor and deformable mirror, and the closed-loop feedbacks adopted in the conventional adaptive optics confocal imaging system, thus reducing the optomechanical complexity and cost. Numerical simulations and proof-of-principle experiments are presented that demonstrate the feasibility of this idea. PMID:26140334

  18. Digital adaptive optics line-scanning confocal imaging system

    NASA Astrophysics Data System (ADS)

    Liu, Changgeng; Kim, Myung K.

    2015-11-01

    A digital adaptive optics line-scanning confocal imaging (DAOLCI) system is proposed by applying digital holographic adaptive optics to a digital form of line-scanning confocal imaging system. In DAOLCI, each line scan is recorded by a digital hologram, which allows access to the complex optical field from one slice of the sample through digital holography. This complex optical field contains both the information of one slice of the sample and the optical aberration of the system, thus allowing us to compensate for the effect of the optical aberration, which can be sensed by a complex guide star hologram. After numerical aberration compensation, the corrected optical fields of a sequence of line scans are stitched into the final corrected confocal image. In DAOLCI, a numerical slit is applied to realize the confocality at the sensor end. The width of this slit can be adjusted to control the image contrast and speckle noise for scattering samples. DAOLCI dispenses with the hardware pieces, such as Shack-Hartmann wavefront sensor and deformable mirror, and the closed-loop feedbacks adopted in the conventional adaptive optics confocal imaging system, thus reducing the optomechanical complexity and cost. Numerical simulations and proof-of-principle experiments are presented that demonstrate the feasibility of this idea.

  19. Automatic Analysis for the Chemical Testing of Urine Examination Using Digital Image Processing Techniques

    NASA Astrophysics Data System (ADS)

    Vilardy, Juan M.; Peña, Jose C.; Daza, Miller F.; Torres, Cesar O.; Mattos, Lorenzo

    2008-04-01

    For to make the chemical testing of urine examination a dipstick is used, which contains pads that have incorporated within them the reagents for chemical reactions for the detection of a number from substances in the urine. Urine is added to the pads for reaction by dipping the dipstick into the urine and then slowly withdrawing it. The subsequent colorimetric reactions are timed to an endpoint; the extent of colors formation is directly related to the level of the urine constituent. The colors can be read manually by comparison with color charts or with the use of automated reflectance meters. The aim of the System described in this paper is to analyze and to determine automatically the changes of the colors in the dipstick when this is retired of the urine sample and to compare the results with color charts for the diagnosis of many common diseases such as diabetes. The system consists of: (a) a USB camera. (b) Computer. (c) Software Matlab v7.4. Image analysis begins with a digital capturing of the image as data. Once the image is acquired in digital format, the data can be manipulated through digital image processing. Our objective was to develop a computerised image processing system and an interactive software package for the backing of clinicians, medical research and medical students.

  20. Communication and storage of digital medical images in database.

    PubMed

    Evangelista, N; Camapum, J; Amemiya, E

    2005-01-01

    This paper presents the development of an application for communication and storage of clinical images based upon the Digital Imaging and Communications in Medicine (DICOM) protocol. The proposed solution is composed of three different databases servers, PostgreSQL, Firebird and Oracle, and a DICOM client software, that uses the protocol TCP/IP. It provides the communication services, transmission, storage and administration of medical images. PMID:17281491

  1. Copyright protection of images in the digital environment.

    PubMed

    Ibbotson, J

    1997-03-01

    All creators of copyright-protected works are re-assessing the protection and exploitation of their works in the digital environment. This article attempts to define 'digital' in a copyright context. It reminds artists and photographers of the essentials of copyright as they already apply in the UK before it looks at how those essentials may apply to images circulating in the digital environment. Finally it covers some of the key issues which artists and other creators are now having to address in their day to day work.

  2. Research on embedding invisible digital watermarking in ultrasonic image

    NASA Astrophysics Data System (ADS)

    Ye, Huashan; Shi, Qing; Ding, Mingyue

    2009-10-01

    In this paper, we proposed an adaptive watermarking algorithm to embed invisible digital watermarking in the wavelet domain of ultrasonic image. By analyzing the characteristic of detail sub-band coefficients of the ultrasonic image after discrete wavelet transform (DWT), we use the mean and variance of the detail sub-bands to modify the wavelet coefficients adaptively, and the embedded watermark is invisible to human visual system (HVS) and adapted to the original image. We can derive the just noticeable different (JND), which describes the maximum signal intensity that the various parts of image can tolerate the digital watermarking. By using this digital watermarking technique we can embed a certainty or confidentiality information directly into original ultrasonic images so that the replication and transmission of ultrasonic image can be tracked efficiently. Therefore, the copyright and ownership of ultrasonic images can be protected, which is critical for the authorization usage of the source of ultrasonic images. The experimental results and attack analysis showed that the proposed algorithm is effective and robust to ultrasonic image processing operations and geometric attacks.

  3. Figure of Image Quality and Information Capacity in Digital Mammography

    PubMed Central

    Michail, Christos M.; Kalyvas, Nektarios E.; Valais, Ioannis G.; Fudos, Ioannis P.; Fountos, George P.; Dimitropoulos, Nikos; Kandarakis, Ioannis S.

    2014-01-01

    Objectives. In this work, a simple technique to assess the image quality characteristics of the postprocessed image is developed and an easy to use figure of image quality (FIQ) is introduced. This FIQ characterizes images in terms of resolution and noise. In addition information capacity, defined within the context of Shannon's information theory, was used as an overall image quality index. Materials and Methods. A digital mammographic image was postprocessed with three digital filters. Resolution and noise were calculated via the Modulation Transfer Function (MTF), the coefficient of variation, and the figure of image quality. In addition, frequency dependent parameters such as the noise power spectrum (NPS) and noise equivalent quanta (NEQ) were estimated and used to assess information capacity. Results. FIQs for the “raw image” data and the image processed with the “sharpen edges” filter were found 907.3 and 1906.1, correspondingly. The information capacity values were 60.86 × 103 and 78.96 × 103 bits/mm2. Conclusion. It was found that, after the application of the postprocessing techniques (even commercial nondedicated software) on the raw digital mammograms, MTF, NPS, and NEQ are improved for medium to high spatial frequencies leading to resolving smaller structures in the final image. PMID:24895593

  4. Viking image processing. [digital stereo imagery and computer mosaicking

    NASA Technical Reports Server (NTRS)

    Green, W. B.

    1977-01-01

    The paper discusses the camera systems capable of recording black and white and color imagery developed for the Viking Lander imaging experiment. Each Viking Lander image consisted of a matrix of numbers with 512 rows and an arbitrary number of columns up to a maximum of about 9,000. Various techniques were used in the processing of the Viking Lander images, including: (1) digital geometric transformation, (2) the processing of stereo imagery to produce three-dimensional terrain maps, and (3) computer mosaicking of distinct processed images. A series of Viking Lander images is included.

  5. Experience with CANDID: Comparison algorithm for navigating digital image databases

    SciTech Connect

    Kelly, P.; Cannon, M.

    1994-10-01

    This paper presents results from the authors experience with CANDID (Comparison Algorithm for Navigating Digital Image Databases), which was designed to facilitate image retrieval by content using a query-by-example methodology. A global signature describing the texture, shape, or color content is first computed for every image stored in a database, and a normalized similarity measure between probability density functions of feature vectors is used to match signatures. This method can be used to retrieve images from a database that are similar to a user-provided example image. Results for three test applications are included.

  6. Experience with CANDID: comparison algorithm for navigating digital image databases

    NASA Astrophysics Data System (ADS)

    Kelly, Patrick M.; Cannon, T. Michael

    1995-01-01

    This paper presents results from our experience with CANDID (comparison algorithm for navigating digital image databases), which was designed to facilitate image retrieval by content using a query-by-example methodology. A global signature describing the texture, shape, or color content is first computed for every image stored in a database, and a normalized similarity measure between probability density functions of feature vectors is used to match signatures. This method can be used to retrieve images from a database that are similar to a user-provided example image. Results for three test applications are included.

  7. Dual Level Digital Watermarking for Images

    NASA Astrophysics Data System (ADS)

    Singh, V. K.; Singh, A. K.

    2010-11-01

    More than 700 years ago, watermarks were used in Italy to indicate the paper brand and the mill that produced it. By the 18th century watermarks began to be used as anti counterfeiting measures on money and other documents.The term watermark was introduced near the end of the 18th century. It was probably given because the marks resemble the effects of water on paper. The first example of a technology similar to digital watermarking is a patent filed in 1954 by Emil Hembrooke for identifying music works. In 1988, Komatsu and Tominaga appear to be the first to use the term "digital watermarking". Consider the following hypothetical situations. You go to a shop, buy some goods and at the counter you are given a currency note you have never come across before. How do you verify that it is not counterfeit? Or say you go to a stationery shop and ask for a ream of bond paper. How do you verify that you have actually been given what you asked for? How does a philatelist verify the authenticity of a stamp? In all these cases, the watermark is used to authenticate. Watermarks have been in existence almost from the time paper has been in use. The impression created by the mesh moulds on the slurry of fibre and water remains on the paper. It serves to identify the manufacturer and thus authenticate the product without actually degrading the aesthetics and utility of the stock. It also makes forgery significantly tougher. Even today, important government and legal documents are watermarked. But what is watermarking, when it comes to digital data? Information is no longer present on a physical material but is represented as a series of zeros and ones. Duplication of information is achieved easily by just reproducing that combination of zeros and ones. How then can one protect ownership rights and authenticate data? The digital watermark is the same as that of conventional watermarks.

  8. Legal aspects of digital image management and communication.

    PubMed

    Laske, C

    1994-01-01

    This paper outlines the legal issues that arise in digital image management and communication systems (IMACS). At the heart of this study is the digital image which is manipulated, processed, communicated, stored, compressed and archived, and which is difficult to ascertain from a legal point of view because of its intangible nature. On the one hand, personal data protection and the patient's right to privacy need to be protected through a data protection and security policy. This is particularly important in view of the capacity of IMACS to integrate with other systems such as HIS and RIS, since the information generated by the totality of these systems offers a very complete picture of any patient. On the other hand, the evanescent nature of the digital image creates legal uncertainties as to questions of evidence, of procedural and legal admissibility and acceptability and of liability.

  9. Transmission of digital images within the NTSC analog format

    DOEpatents

    Nickel, George H.

    2004-06-15

    HDTV and NTSC compatible image communication is done in a single NTSC channel bandwidth. Luminance and chrominance image data of a scene to be transmitted is obtained. The image data is quantized and digitally encoded to form digital image data in HDTV transmission format having low-resolution terms and high-resolution terms. The low-resolution digital image data terms are transformed to a voltage signal corresponding to NTSC color subcarrier modulation with retrace blanking and color bursts to form a NTSC video signal. The NTSC video signal and the high-resolution digital image data terms are then transmitted in a composite NTSC video transmission. In a NTSC receiver, the NTSC video signal is processed directly to display the scene. In a HDTV receiver, the NTSC video signal is processed to invert the color subcarrier modulation to recover the low-resolution terms, where the recovered low-resolution terms are combined with the high-resolution terms to reconstruct the scene in a high definition format.

  10. Fuzzy Index to Evaluate Edge Detection in Digital Images

    PubMed Central

    Perez-Ornelas, Felicitas; Mendoza, Olivia; Melin, Patricia; Castro, Juan R.; Rodriguez-Diaz, Antonio; Castillo, Oscar

    2015-01-01

    In literature, we can find different metrics to evaluate the detected edges in digital images, like Pratt's figure of merit (FOM), Jaccard’s index (JI) and Dice’s coefficient (DC). These metrics compare two images, the first one is the reference edges image, and the second one is the detected edges image. It is important to mention that all existing metrics must binarize images before their evaluation. Binarization step causes information to be lost because an incomplete image is being evaluated. In this paper, we propose a fuzzy index (FI) for edge evaluation that does not use a binarization step. In order to process all detected edges, images are represented in their fuzzy form and all calculations are made with fuzzy sets operators and fuzzy Euclidean distance between both images. Our proposed index is compared to the most used metrics using synthetic images, with good results. PMID:26115362

  11. Complications of sporadic, hereditary, and acquired renal cysts: cross-sectional imaging findings.

    PubMed

    Tonolini, Massimo; Rigiroli, Francesca; Villa, Federica; Bianco, Roberto

    2014-01-01

    Commonly encountered in the general adult and elderly population, in most cases simple renal cysts are confidently diagnosed on imaging studies and do not require further workup or treatment. However, large or growing renal cysts sometimes cause symptoms or signs such as hypertension, palpable mass, flank or abdominal pain, obstructive uropathy, and hematuria, which may indicate the need for minimally invasive percutaneous or laparoscopic treatment. Furthermore, severe complications such as cystic hemorrhage, rupture, or superinfection may occur, particularly in patients with polycystic renal disorders, either hereditary (namely adult polycystic kidney diseases) or acquired in chronic renal failure. This pictorial essay reviews and discusses the cross-sectional imaging appearances of symptomatic and complicated sporadic, hereditary, and acquired renal cysts. Early cross-sectional imaging with multidetector computed tomography or magnetic resonance imaging or both, including contrast enhancement unless contraindicated by renal dysfunction, is warranted to investigate clinical and laboratory signs suggesting retroperitoneal hemorrhage or infection in patients with pre-existent renal cysts, particularly if large, multiple, or hereditary.

  12. On detection of median filtering in digital images

    NASA Astrophysics Data System (ADS)

    Kirchner, Matthias; Fridrich, Jessica

    2010-01-01

    In digital image forensics, it is generally accepted that intentional manipulations of the image content are most critical and hence numerous forensic methods focus on the detection of such 'malicious' post-processing. However, it is also beneficial to know as much as possible about the general processing history of an image, including content-preserving operations, since they can affect the reliability of forensic methods in various ways. In this paper, we present a simple yet effective technique to detect median filtering in digital images-a widely used denoising and smoothing operator. As a great variety of forensic methods relies on some kind of a linearity assumption, a detection of non-linear median filtering is of particular interest. The effectiveness of our method is backed with experimental evidence on a large image database.

  13. A new method to acquire 3-D images of a dental cast

    NASA Astrophysics Data System (ADS)

    Li, Zhongke; Yi, Yaxing; Zhu, Zhen; Li, Hua; Qin, Yongyuan

    2006-01-01

    This paper introduced our newly developed method to acquire three-dimensional images of a dental cast. A rotatable table, a laser-knife, a mirror, a CCD camera and a personal computer made up of a three-dimensional data acquiring system. A dental cast is placed on the table; the mirror is installed beside the table; a linear laser is projected to the dental cast; the CCD camera is put up above the dental cast, it can take picture of the dental cast and the shadow in the mirror; while the table rotating, the camera records the shape of the laser streak projected on the dental cast, and transmit the data to the computer. After the table rotated one circuit, the computer processes the data, calculates the three-dimensional coordinates of the dental cast's surface. In data processing procedure, artificial neural networks are enrolled to calibrate the lens distortion, map coordinates form screen coordinate system to world coordinate system. According to the three-dimensional coordinates, the computer reconstructs the stereo image of the dental cast. It is essential for computer-aided diagnosis and treatment planning in orthodontics. In comparison with other systems in service, for example, laser beam three-dimensional scanning system, the characteristic of this three-dimensional data acquiring system: a. celerity, it casts only 1 minute to scan a dental cast; b. compact, the machinery is simple and compact; c. no blind zone, a mirror is introduced ably to reduce blind zone.

  14. Digital Images and the Z-Axis

    ERIC Educational Resources Information Center

    Cross, Judie

    2010-01-01

    This article argues that while a semiotic analysis of composition in the screen, page and image has significant heuristic value, this would be further enhanced were it also to take into account surface and depth. It is argued that these two aspects of composition are critical for successful reading/viewing of images, and especially for digital…

  15. A novel method to acquire 3D data from serial 2D images of a dental cast

    NASA Astrophysics Data System (ADS)

    Yi, Yaxing; Li, Zhongke; Chen, Qi; Shao, Jun; Li, Xinshe; Liu, Zhiqin

    2007-05-01

    This paper introduced a newly developed method to acquire three-dimensional data from serial two-dimensional images of a dental cast. The system consists of a computer and a set of data acquiring device. The data acquiring device is used to take serial pictures of the a dental cast; an artificial neural network works to translate two-dimensional pictures to three-dimensional data; then three-dimensional image can reconstruct by the computer. The three-dimensional data acquiring of dental casts is the foundation of computer-aided diagnosis and treatment planning in orthodontics.

  16. Balanced Multiwavelets Based Digital Image Watermarking

    NASA Astrophysics Data System (ADS)

    Zhang, Na; Huang, Hua; Zhou, Quan; Qi, Chun

    In this paper, an adaptive blind watermarking algorithm based on balanced multiwavelets transform is proposed. According to the properties of balanced multiwavelets and human vision system, a modified version of the well-established Lewis perceptual model is given. Therefore, the strength of embedded watermark is controlled by the local properties of the host image .The subbands of balanced multiwavelets transformation are similar to each other in the same scale, so the most similar subbands are chosen to embed the watermark by modifying the relation of the two subbands adaptively under the model, the watermark extraction can be performed without original image. Experimental results show that the watermarked images look visually identical to the original ones, and the watermark also successfully survives after image processing operations such as image cropping, scaling, filtering and JPEG compression.

  17. Digital replacement of the distorted dentition acquired by cone beam computed tomography (CBCT): a pilot study.

    PubMed

    Nairn, N J; Ayoub, A F; Barbenel, J; Moos, K; Naudi, K; Ju, X; Khambay, B S

    2013-11-01

    During cone beam computed tomography (CBCT) scanning, intra-oral metallic objects may produce streak artefacts, which impair the occlusal surface of the teeth. This study aimed to determine the accuracy of replacement of the CBCT dentition with a more accurate dentition and to determine the clinical feasibility of the method. Impressions of the teeth of six cadaveric skulls with unrestored dentitions were taken and acrylic base plates constructed incorporating radiopaque registration markers. Each appliance was fitted to the skull and a CBCT performed. Impressions were taken of the dentition with the devices in situ and dental models were produced. These were CBCT-scanned and the images of the skulls and models imported into computer-aided design/computer-aided manufacturing (CAD/CAM) software and aligned on the registration markers. The occlusal surfaces of each dentition were then replaced with the occlusal image of the corresponding model. The absolute mean distance between the registration markers in the skulls and the dental models was 0.09±0.02mm, and for the dentition was 0.24±0.09mm. When the method was applied to patients, the distance between markers was 0.12±0.04mm for the maxilla and 0.16±0.02mm for the mandible. It is possible to replace the inaccurate dentition on a CBCT scan using this method and to create a composite skull which is clinically acceptable.

  18. Determination of localization accuracy based on experimentally acquired image sets: applications to single molecule microscopy

    PubMed Central

    Tahmasbi, Amir; Ward, E. Sally; Ober, Raimund J.

    2015-01-01

    Fluorescence microscopy is a photon-limited imaging modality that allows the study of subcellular objects and processes with high specificity. The best possible accuracy (standard deviation) with which an object of interest can be localized when imaged using a fluorescence microscope is typically calculated using the Cramér-Rao lower bound, that is, the inverse of the Fisher information. However, the current approach for the calculation of the best possible localization accuracy relies on an analytical expression for the image of the object. This can pose practical challenges since it is often difficult to find appropriate analytical models for the images of general objects. In this study, we instead develop an approach that directly uses an experimentally collected image set to calculate the best possible localization accuracy for a general subcellular object. In this approach, we fit splines, i.e. smoothly connected piecewise polynomials, to the experimentally collected image set to provide a continuous model of the object, which can then be used for the calculation of the best possible localization accuracy. Due to its practical importance, we investigate in detail the application of the proposed approach in single molecule fluorescence microscopy. In this case, the object of interest is a point source and, therefore, the acquired image set pertains to an experimental point spread function. PMID:25837101

  19. Determination of localization accuracy based on experimentally acquired image sets: applications to single molecule microscopy.

    PubMed

    Tahmasbi, Amir; Ward, E Sally; Ober, Raimund J

    2015-03-23

    Fluorescence microscopy is a photon-limited imaging modality that allows the study of subcellular objects and processes with high specificity. The best possible accuracy (standard deviation) with which an object of interest can be localized when imaged using a fluorescence microscope is typically calculated using the Cramér-Rao lower bound, that is, the inverse of the Fisher information. However, the current approach for the calculation of the best possible localization accuracy relies on an analytical expression for the image of the object. This can pose practical challenges since it is often difficult to find appropriate analytical models for the images of general objects. In this study, we instead develop an approach that directly uses an experimentally collected image set to calculate the best possible localization accuracy for a general subcellular object. In this approach, we fit splines, i.e. smoothly connected piecewise polynomials, to the experimentally collected image set to provide a continuous model of the object, which can then be used for the calculation of the best possible localization accuracy. Due to its practical importance, we investigate in detail the application of the proposed approach in single molecule fluorescence microscopy. In this case, the object of interest is a point source and, therefore, the acquired image set pertains to an experimental point spread function. PMID:25837101

  20. Probability-based tampering detection scheme for digital images

    NASA Astrophysics Data System (ADS)

    Hsu, Ching-Sheng; Tu, Shu-Fen

    2010-05-01

    In recent years, digital watermarking technology has been widely used for property rights protection and integrity authentication of digital images. Image integrity authentication is usually done by a fragile watermarking scheme. When authenticating image integrity, one must extract the embedded authentication message from the image for comparison with the image feature to identify whether the image has been tampered with, and if so, locate the affected area. However, such authentication schemes may result in detection error problems. Namely, the tampered area may be misjudged as not having been tampered with, or vice versa. Hence, methods that effectively reduce errors in tampering detection have become an important research topic. This study aims to integrate a probability theory to improve image tampering detection accuracy and precision. The scheme includes two processes: the embedding of an image authentication message and tampering detection. In the image tampering detection process, in addition to identifying whether the image has been tampered with and locating the tampered area, through the authentication message embedded in the image, a probability theory is employed to improve previously obtained detection results to enhance authentication accuracy. The experimental results reveal that the proposed scheme performs well in terms of detection precision and authentication accuracy rate.

  1. Photon-to-digital photodiode imaging array

    NASA Astrophysics Data System (ADS)

    Mandl, William J.

    2001-10-01

    MOSAD©, Multiplexed OverSample Analog to Digital conversion, is a low power on focal plane analog to digital, A/D, process that places an oversample A/D at each pixel site. Two designs for a visible light staring array were developed with this approach. One used a silicon photo diode and the other used a photo gate for detection. The array was designed with a 320 X 240 format with the pixels placed on 16 micron centers. There are a total of 76,800 A/D's on the chip. The device is a monolithic integrated circuit that includes the sensors, A/D's and readout circuitry. A production 1.2 micron CCD/CMOS process was used in it construction. The A/D uses charge well switching at the pixel to convert the accumulated analog signal to digital data. There was negligible impact on the pixel area due to the A/D such that a fill factor of 73% was achieved with front side illumination for both approaches. At 400 samples per second, measured on chip power consumption is under 10 milliwatts. Noise measurements at sample rates from 400 samples per second to 1,600 samples per second were taken for both parts. It was found that the photo gate noise performance was four times better than the photo diode. At a nominal 28 times oversample, the photo diode obtained 8 to 9 bits performance and the photo gate achieved 10 to 11 bits. Nonuniformity variation was below the noise floor. No explanation for the difference in noise performance has yet been determined. This development was sponsored by NASA under a SBIR program.

  2. Analog and digital systems of imaging in roentgenodiagnostics.

    PubMed

    Oborska-Kumaszyńska, Dominika; Wiśniewska-Kubka, Sylwia

    2010-04-01

    In the recent years, we have been witnessing a very dynamic development of diagnostic methods of imaging. In contemporary radiology, the carrier of the diagnostic information is the image, obtained as a result of an X-ray beam transmitted through the patient's body, with modulation of intensity, and processing of data collected by the detector. Depending on the diagnostic method used, signals can be detected with analog (x-ray film) or digital systems (CR, DR and DDR). Each of these methods of image acquisition, due to its own technological solutions, determines a different quality of imaging (diagnostic data). The introduction of digital image receptors, instead of conventional SF systems, increased the patient dose, as a result of a gradually increasing exposure. This followed from the fact that in digital systems, the increased radiation dose reduces image noise and improves image quality, and that is owing to the data capacity of these systems (impossible in SF systems with a limited data capacity of the image detector). The availability of the multitude of imaging systems, each characterized by disparate qualitative and quantitative parameters, implies the problem of evaluation and enforcement of a proper efficiency from manufacturers of these systems.At the same time, there is a legal problem present in our country, i.e. the lack of laws and regulations regarding standards of the scope of quality control (parameters) and measurement methodology for the systems of digital image acquisition. In the European countries, the scope and standards of control are regulated by the manufacturers and European Guidelines, whereas in the United States, AAPM Reports have been introduced, that specifically describe methods of tests performance, their frequency, as well as target values and limits. This paper is a review of both, the scope of quality control parameters of image detectors in analog and digital systems of imaging, and the measurement methodology. The parameters

  3. Analog and digital systems of imaging in roentgenodiagnostics

    PubMed Central

    Oborska-Kumaszyńska, Dominika; Wiśniewska-Kubka, Sylwia

    2010-01-01

    Summary In the recent years, we have been witnessing a very dynamic development of diagnostic methods of imaging. In contemporary radiology, the carrier of the diagnostic information is the image, obtained as a result of an X-ray beam transmitted through the patient’s body, with modulation of intensity, and processing of data collected by the detector. Depending on the diagnostic method used, signals can be detected with analog (x-ray film) or digital systems (CR, DR and DDR). Each of these methods of image acquisition, due to its own technological solutions, determines a different quality of imaging (diagnostic data). The introduction of digital image receptors, instead of conventional SF systems, increased the patient dose, as a result of a gradually increasing exposure. This followed from the fact that in digital systems, the increased radiation dose reduces image noise and improves image quality, and that is owing to the data capacity of these systems (impossible in SF systems with a limited data capacity of the image detector). The availability of the multitude of imaging systems, each characterized by disparate qualitative and quantitative parameters, implies the problem of evaluation and enforcement of a proper efficiency from manufacturers of these systems. At the same time, there is a legal problem present in our country, i.e. the lack of laws and regulations regarding standards of the scope of quality control (parameters) and measurement methodology for the systems of digital image acquisition. In the European countries, the scope and standards of control are regulated by the manufacturers and European Guidelines, whereas in the United States, AAPM Reports have been introduced, that specifically describe methods of tests performance, their frequency, as well as target values and limits. This paper is a review of both, the scope of quality control parameters of image detectors in analog and digital systems of imaging, and the measurement methodology. The

  4. Detecting Nematode Features from Digital Images

    PubMed Central

    de la Blanca, N. Pérez; Fdez-Valdivia, J.; Castillo, P.; Gómez-Barcina, A.

    1992-01-01

    Procedures for estimating and calibrating nematode features from digitial images are described and evaluated by illustration and mathematical formulae. Technical problems, such as capturing and cleaning raw images, standardizing the grey level range of images, and the detection of characteristics of the body habitus, presence or absence of stylet knobs, and tail and lip region shape are discussed. This study is the first of a series aimed at developing a set of automated methods to permit more rapid, objective characterizations of nematode features than is achievable by cumbersome conventional methods. PMID:19282998

  5. A methodology for high resolution digital image correlation in high temperature experiments.

    PubMed

    Blaber, Justin; Adair, Benjamin S; Antoniou, Antonia

    2015-03-01

    We propose a methodology for performing high resolution Digital Image Correlation (DIC) analysis during high-temperature mechanical tests. Specifically, we describe a technique for producing a stable, high-quality pattern on metal surfaces along with a simple optical system that uses a visible-range camera and a long-range microscope. The results are analyzed with a high-quality open-source DIC software developed by us. Using the proposed technique, we successfully acquired high-resolution strain maps of the crack tip field in a nickel superalloy sample at 1000 °C. PMID:25832279

  6. Digital tomosynthesis with an on-board kilovoltage imaging device

    SciTech Connect

    Godfrey, Devon J. . E-mail: devon.godfrey@duke.edu; Yin, F.-F.; Oldham, Mark; Yoo, Sua; Willett, Christopher

    2006-05-01

    Purpose: To generate on-board digital tomosynthesis (DTS) and reference DTS images for three-dimensional image-guided radiation therapy (IGRT) as an alternative to conventional portal imaging or on-board cone-beam computed tomography (CBCT). Methods and Materials: Three clinical cases (prostate, head-and-neck, and liver) were selected to illustrate the capabilities of on-board DTS for IGRT. Corresponding reference DTS images were reconstructed from digitally reconstructed radiographs computed from planning CT image sets. The effect of scan angle on DTS slice thickness was examined by computing the mutual information between coincident CBCT and DTS images, as the DTS scan angle was varied from 0{sup o} to 165{sup o}. A breath-hold DTS acquisition strategy was implemented to remove respiratory motion artifacts. Results: Digital tomosynthesis slices appeared similar to coincident CBCT planes and yielded substantially more anatomic information than either kilovoltage or megavoltage radiographs. Breath-hold DTS acquisition improved soft-tissue visibility by suppressing respiratory motion. Conclusions: Improved bony and soft-tissue visibility in DTS images is likely to improve target localization compared with radiographic verification techniques and might allow for daily localization of a soft-tissue target. Breath-hold DTS is a potential alternative to on-board CBCT for sites prone to respiratory motion.

  7. Highest Resolution Image of Dust and Sand Yet Acquired on Mars

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] [figure removed for brevity, see original site] Click on image for Figure 1Click on image for Figure 2Click on image for Figure 3

    This mosaic of four side-by-side microscope images (one a color composite) was acquired by the Optical Microscope, a part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on NASA's Phoenix Mars Lander. Taken on the ninth Martian day of the mission, or Sol 9 (June 3, 2008), the image shows a 3 millimeter (0.12 inch) diameter silicone target after it has been exposed to dust kicked up by the landing. It is the highest resolution image of dust and sand ever acquired on Mars. The silicone substrate provides a sticky surface for holding the particles to be examined by the microscope.

    Martian Particles on Microscope's Silicone Substrate In figure 1, the particles are on a silcone substrate target 3 millimeters (0.12 inch) in diameter, which provides a sticky surface for holding the particles while the microscope images them. Blow-ups of four of the larger particles are shown in the center. These particles range in size from about 30 microns to 150 microns (from about one one-thousandth of an inch to six one-thousandths of an inch).

    Possible Nature of Particles Viewed by Mars Lander's Optical Microscope In figure 2, the color composite on the right was acquired to examine dust that had fallen onto an exposed surface. The translucent particle highlighted at bottom center is of comparable size to white particles in a Martian soil sample (upper pictures) seen two sols earlier inside the scoop of Phoenix's Robotic Arm as imaged by the lander's Robotic Arm Camera. The white particles may be examples of the abundant salts that have been found in the Martian soil by previous missions. Further investigations will be needed to determine the white material's composition and whether translucent particles

  8. CANDID: Comparison algorithm for navigating digital image databases

    SciTech Connect

    Kelly, P.M.; Cannon, T.M.

    1994-02-21

    In this paper, we propose a method for calculating the similarity between two digital images. A global signature describing the texture, shape, or color content is first computed for every image stored in a database, and a normalized distance between probability density functions of feature vectors is used to match signatures. This method can be used to retrieve images from a database that are similar to an example target image. This algorithm is applied to the problem of search and retrieval for database containing pulmonary CT imagery, and experimental results are provided.

  9. Performance of the SIR-B digital image processing subsystem

    NASA Technical Reports Server (NTRS)

    Curlander, J. C.

    1986-01-01

    A ground-based system to generate digital SAR image products has been developed and implemented in support of the SIR-B mission. This system is designed to achieve the maximum throughput while meeting strict image fidelity criteria. Its capabilities include: automated radiometric and geometric correction of the output imagery; high-precision absolute location without tiepoint registration; filtering of the raw data to remove spurious signals from alien radars; and automated catologing to maintain a full set of radar and image production facility in support of the SIR-B science investigators routinely produces over 80 image frames per week.

  10. Segmentation and image navigation in digitized spine x rays

    NASA Astrophysics Data System (ADS)

    Long, L. Rodney; Thoma, George R.

    2000-06-01

    The National Library of Medicine has archived a collection of 17,000 digitized x-rays of the cervical and lumbar spines. Extensive health information has been collected on the subjects of these x-rays, but no information has been derived from the image contents themselves. We are researching algorithms to segment anatomy in these images and to derive from the segmented data measurements useful for indexing this image set for characteristics important to researchers in rheumatology, bone morphometry, and related areas. Active Shape Modeling is currently being investigated for use in location and boundary definition for the vertebrae in these images.

  11. Design and DSP implementation of star image acquisition and star point fast acquiring and tracking

    NASA Astrophysics Data System (ADS)

    Zhou, Guohui; Wang, Xiaodong; Hao, Zhihang

    2006-02-01

    Star sensor is a special high accuracy photoelectric sensor. Attitude acquisition time is an important function index of star sensor. In this paper, the design target is to acquire 10 samples per second dynamic performance. On the basis of analyzing CCD signals timing and star image processing, a new design and a special parallel architecture for improving star image processing are presented in this paper. In the design, the operation moving the data in expanded windows including the star to the on-chip memory of DSP is arranged in the invalid period of CCD frame signal. During the CCD saving the star image to memory, DSP processes the data in the on-chip memory. This parallelism greatly improves the efficiency of processing. The scheme proposed here results in enormous savings of memory normally required. In the scheme, DSP HOLD mode and CPLD technology are used to make a shared memory between CCD and DSP. The efficiency of processing is discussed in numerical tests. Only in 3.5ms is acquired the five lightest stars in the star acquisition stage. In 43us, the data in five expanded windows including stars are moved into the internal memory of DSP, and in 1.6ms, five star coordinates are achieved in the star tracking stage.

  12. Digital Image Encryption Scheme Based on Multiple Chaotic Systems

    NASA Astrophysics Data System (ADS)

    Abd El-Latif, Ahmed A.; Li, Li; Zhang, Tiejun; Wang, Ning; Song, Xianhua; Niu, Xiamu

    2012-06-01

    Image encryption is a challenging task due to the significant level of sophistication achieved by forgerers and other cybercriminals. Advanced encryption methods for secure transmission, storage, and retrieval of digital images are increasingly needed for a number of military, medical, homeland security, and other applications. In this paper, we introduce a new digital image encryption algorithm. The new algorithm employs multiple chaotic systems and cryptographic primitive operations within the encryption process, which are efficiently implemented on modern processors, and adopts round keys for encryption using a chaotic map. Experiments conducted show that the proposed algorithm possesses robust security features such as fairly uniform distribution, high sensitivity to both keys and plainimages, almost ideal entropy, and the ability to highly de-correlate adjacent pixels in the cipherimages. Furthermore, it has a large key space, which greatly increases its security for image encryption applications.

  13. Integrating digital topology in image-processing libraries.

    PubMed

    Lamy, Julien

    2007-01-01

    This paper describes a method to integrate digital topology informations in image-processing libraries. This additional information allows a library user to write algorithms respecting topological constraints, for example, a seed fill or a skeletonization algorithm. As digital topology is absent from most image-processing libraries, such constraints cannot be fulfilled. We describe and give code samples for all the structures necessary for this integration, and show a use case in the form of a homotopic thinning filter inside ITK. The obtained filter can be up to a hundred times as fast as ITK's thinning filter and works for any image dimension. This paper mainly deals of integration within ITK, but can be adapted with only minor modifications to other image-processing libraries.

  14. A pragmatic discussion on establishing a multicenter digital imaging network.

    PubMed

    Ingeholm, Mary Lou; Levine, Betty A; Fatemi, Seyed Ali; Moser, And Hugo W

    2002-01-01

    Multicenter clinical trials for therapy evaluation of rare diseases are necessary. A digital imaging network improves the ability to share information between collaborating institutions for adrenoleukodystrophy. The DICOM 3.0 standard is used to move images over the Internet from contributing sites to the central clinical database and on to the reviewing physicians' workstations. Patient confidentiality and data integrity are ensured during transmission using virtual private network technology. Fifteen sites are participating in the network. Of these sites, 6 use the proposed protocol. The other 9 sites have either security policy issues or technical considerations that dictate alternative protocols. Network infrastructure, Internet access, image management practices, and security policies vary significantly between sites. Successful implementation of a multicenter digital imaging network requires flexibility in the implementation of network connectivity. Flexibility increases participation as well as complexity of the network. PMID:12105723

  15. Parallel digital signal processing architectures for image processing

    NASA Astrophysics Data System (ADS)

    Kshirsagar, Shirish P.; Hartley, David A.; Harvey, David M.; Hobson, Clifford A.

    1994-10-01

    This paper describes research into a high speed image processing system using parallel digital signal processors for the processing of electro-optic images. The objective of the system is to reduce the processing time of non-contact type inspection problems including industrial and medical applications. A single processor can not deliver sufficient processing power required for the use of applications hence, a MIMD system is designed and constructed to enable fast processing of electro-optic images. The Texas Instruments TMS320C40 digital signal processor is used due to its high speed floating point CPU and the support for the parallel processing environment. A custom designed VISION bus is provided to transfer images between processors. The system is being applied for solder joint inspection of high technology printed circuit boards.

  16. A megavoltage scatter correction technique for cone-beam CT images acquired during VMAT delivery.

    PubMed

    Boylan, C J; Marchant, T E; Stratford, J; Malik, J; Choudhury, A; Shrimali, R; Rodgers, J; Rowbottom, C G

    2012-06-21

    Kilovoltage cone-beam CT (kV CBCT) can be acquired during the delivery of volumetric modulated arc therapy (VMAT), in order to obtain an image of the patient during treatment. However, the quality of such CBCTs is degraded by megavoltage (MV) scatter from the treatment beam onto the imaging panel. The objective of this paper is to introduce a novel MV scatter correction method for simultaneous CBCT during VMAT, and to investigate its effectiveness when compared to other techniques. The correction requires the acquisition of a separate set of images taken during VMAT delivery, while the kV beam is off. These images--which contain only the MV scatter contribution on the imaging panel--are then used to correct the corresponding kV/MV projections. To test this method, CBCTs were taken of an image quality phantom during VMAT delivery and measurements of contrast to noise ratio were made. Additionally, the correction was applied to the datasets of three VMAT prostate patients, who also received simultaneous CBCTs. The clinical image quality was assessed using a validated scoring system, comparing standard CBCTs to the uncorrected simultaneous CBCTs and a variety of correction methods. Results show that the correction is able to recover some of the low and high-contrast signal to noise ratio lost due to MV scatter. From the patient study, the corrected CBCT scored significantly higher than the uncorrected images in terms of the ability to identify the boundary between the prostate and surrounding soft tissue. In summary, a simple MV scatter correction method has been developed and, using both phantom and patient data, is shown to improve the image quality of simultaneous CBCTs taken during VMAT delivery.

  17. Digital magnification of three-dimensional integral imaging using image interpolation algorithms

    NASA Astrophysics Data System (ADS)

    Ponce-Díaz, Rodrigo; Song, Yong-Wook; Javidi, Bahram

    2005-11-01

    We can enlarge or reduce three-dimensional integral imaging images by using an optical multi-pickup method. We used the moving array- lenslet technique (MALT) to increase the spatial ray sampling rate of elemental images in the optical method. In this paper, we are proposing a digital magnification method to increase the spatial ray sampling rate without lens movement. The major drawback of the optical technique is the complexity due to the small lenslet movement. We used four popular two dimensional (2D) magnified interpolation methods, as: linear, cubic, spline and nearest. We compared the reconstructed integral imaging images using optical and digital magnification methods. When use the optical and digital magnification are used in a sequence, we can reduce the number of pickup procedures for the optical method to a forth while we can see almost the same resolution quality of the reconstructed integral imaging images.

  18. Image capture and printing system for digitally generated medical-diagnostic images

    NASA Astrophysics Data System (ADS)

    Stone, Barry; Bronkalla, Mark D.

    1990-08-01

    The printing of digitally generated images from medical diagnostic equipment has typically been done on analog systems after D to A conversion. Newer digital printing systems do not generally yield optimum results since they re-sample the incoming video signal according to their own internal pixel matrix. This leads to a loss of contrast and resolution plus the introduction of aliasing artifacts into the image. Using the method of synchronous sampling of the incoming video signal an almost perfect digitization of the original image can be achieved. Starting with the known display pixel matrix the pixel display clock can be regenerated by a precision phase locked frequency synthesizer. Quantizing levels are duplicated through calibration of the system. Sampling phase error is adjusted out such that each pixel is sampled at its center. Comparison with non-synchronous techniques and multi-generation performance of this system will be demonstrated. The images are then transferred digitally on disk for storage and later printing by a CRT based slow scan camera system. Image parameter files saved with the image allow the camera to generate a gamma correction look-up table for printing. The film image will then precisely and consistently match the CRT image viewed by the system operator. The system is capable of digitizing and printing up to 10242 images with the same high quality as the original displayed image.

  19. Digital hardware and software design for infrared sensor image processing

    NASA Astrophysics Data System (ADS)

    Bekhtin, Yuri; Barantsev, Alexander; Solyakov, Vladimir; Medvedev, Alexander

    2005-06-01

    The example of the digital hardware-and-software complex consisting of the multi-element matrix sensor the personal computer along with the installed special card AMBPCI is described. The problems of elimination socalled fixed pattern noise (FPN) are considered. To improve current imaging the residual FPN is represented as a multiplicative noise. The wavelet-based de-noising algorithm using sets of noisy and non-noisy data of images is applied.

  20. Digital image processing for the earth resources technology satellite data.

    NASA Technical Reports Server (NTRS)

    Will, P. M.; Bakis, R.; Wesley, M. A.

    1972-01-01

    This paper discusses the problems of digital processing of the large volumes of multispectral image data that are expected to be received from the ERTS program. Correction of geometric and radiometric distortions are discussed and a byte oriented implementation is proposed. CPU timing estimates are given for a System/360 Model 67, and show that a processing throughput of 1000 image sets per week is feasible.

  1. Digital interactive image analysis by array processing

    NASA Technical Reports Server (NTRS)

    Sabels, B. E.; Jennings, J. D.

    1973-01-01

    An attempt is made to draw a parallel between the existing geophysical data processing service industries and the emerging earth resources data support requirements. The relationship of seismic data analysis to ERTS data analysis is natural because in either case data is digitally recorded in the same format, resulting from remotely sensed energy which has been reflected, attenuated, shifted and degraded on its path from the source to the receiver. In the seismic case the energy is acoustic, ranging in frequencies from 10 to 75 cps, for which the lithosphere appears semi-transparent. In earth survey remote sensing through the atmosphere, visible and infrared frequency bands are being used. Yet the hardware and software required to process the magnetically recorded data from the two realms of inquiry are identical and similar, respectively. The resulting data products are similar.

  2. Adaptive color contrast enhancement for digital images

    NASA Astrophysics Data System (ADS)

    Wang, Yanfang; Luo, Yupin

    2011-11-01

    Noncanonical illumination that is too dim or with color cast induces degenerated images. To cope with this, we propose a method for color-contrast enhancement. First, intensity, chrominance, and contrast characteristics are explored and integrated in the Naka-Rushton equation to remove underexposure and color cast simultaneously. Motivated by the comparison mechanism in Retinex, the ratio of each pixel to its surroundings is utilized to improve image contrast. Finally, inspired by the two color-opponent dimensions in CIELAB space, a color-enhancement strategy is devised based on the transformation from CIEXYZ to CIELAB color space. For images that suffer from underexposure, color cast, or both problems, our algorithm produces promising results without halo artifacts and corruption of uniform areas.

  3. Matching rendered and real world images by digital image processing

    NASA Astrophysics Data System (ADS)

    Mitjà, Carles; Bover, Toni; Bigas, Miquel; Escofet, Jaume

    2010-05-01

    Recent advances in computer-generated images (CGI) have been used in commercial and industrial photography providing a broad scope in product advertising. Mixing real world images with those rendered from virtual space software shows a more or less visible mismatching between corresponding image quality performance. Rendered images are produced by software which quality performance is only limited by the resolution output. Real world images are taken with cameras with some amount of image degradation factors as lens residual aberrations, diffraction, sensor low pass anti aliasing filters, color pattern demosaicing, etc. The effect of all those image quality degradation factors can be characterized by the system Point Spread Function (PSF). Because the image is the convolution of the object by the system PSF, its characterization shows the amount of image degradation added to any taken picture. This work explores the use of image processing to degrade the rendered images following the parameters indicated by the real system PSF, attempting to match both virtual and real world image qualities. The system MTF is determined by the slanted edge method both in laboratory conditions and in the real picture environment in order to compare the influence of the working conditions on the device performance; an approximation to the system PSF is derived from the two measurements. The rendered images are filtered through a Gaussian filter obtained from the taking system PSF. Results with and without filtering are shown and compared measuring the contrast achieved in different final image regions.

  4. Study of optical techniques for the Ames unitary wind tunnel: Digital image processing, part 6

    NASA Technical Reports Server (NTRS)

    Lee, George

    1993-01-01

    A survey of digital image processing techniques and processing systems for aerodynamic images has been conducted. These images covered many types of flows and were generated by many types of flow diagnostics. These include laser vapor screens, infrared cameras, laser holographic interferometry, Schlieren, and luminescent paints. Some general digital image processing systems, imaging networks, optical sensors, and image computing chips were briefly reviewed. Possible digital imaging network systems for the Ames Unitary Wind Tunnel were explored.

  5. Using Digital Images with Young Children: Challenges of Integration

    ERIC Educational Resources Information Center

    Schiller, John; Tillett, Beryl

    2004-01-01

    In what ways can information and communications technologies (ICT) be integrated into classroom practice to create a 'community of learners'? This paper describes an action research project, over a six-month period, in which a class of seven-year-old and eight-year-old children in a metropolitan South Australian school created digital images to…

  6. An algorithm for approximate rectification of digital aerial images

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-resolution aerial photography is one of the most valuable tools available for managing extensive landscapes. With recent advances in digital camera technology, computer hardware, and software, aerial photography is easier to collect, store, and transfer than ever before. Images can be automa...

  7. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200506-00198-08). June 2005. DUCTWORK BETWEEN FAN ROOM AND PASSAGEWAY UNDER BEVATRON, SOUTH SIDE OF ROOM 10, MAIN FLOOR, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  8. Photocopy of photograph (digital image maintained in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image maintained in LBNL Photo Lab Collection, XBD200503-00117-176). March 2005. CENTRAL COLUMN SUPPORT TO ROOF SHOWING CRANES CENTER SUPPORT TRACK, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  9. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-049). March 2005. TUNNEL ENTRY FROM MAIN FLOOR OF MAGNET ROOM INTO CENTER OF BEVATRON, BENEATH SOUTHWEST QUADRANT - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  10. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-034). March 2005. MOUSE AT EAST TANGENT WITH COVER CLOSED, LOOKING TOWARD CENTER IGLOO, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  11. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200506-00198-11). June 2005. DUCTWORK BETWEEN FAN ROOM AND PASSAGEWAY UNDER BEVATRON, NORTH SIDE OF ROOM 10, MAIN FLOOR, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  12. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-129). March 2005. ENTRY TO ROOM 24, MAIN FLOOR, OFFICE-AND-SHOPS SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  13. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-035). March 2005. WEST TANGENT VIEWED FROM INTERIOR OF BEVATRON. EQUIPMENT ACCESS STAIRWAY ON LEFT - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  14. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-009). March 2005. OPENINGS OF AIR DUCTS INTO PASSAGEWAY UNDER SOUTHEAST QUADRANT, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  15. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-031). March 2005. MOUSE AT EAST TANGENT, WITH COVER OPEN, LOOKING TOWARD CENTER IGLOO, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  16. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-046). March 2005. ROOF SHIELDING BLOCK AND I-BEAM SUPPORT CONSTRUCTION, CENTER OF BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  17. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200503-00117-139). March 2005. TOP OF BEVATRON, INCLUDING WOOD STAIRWAY FROM OUTER EDGE OF SHIELDING TO TOP OF ROOF BLOCK SHIELDING - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  18. Photocopy of photograph (digital image located in LBNL Photo Lab ...

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

    Photocopy of photograph (digital image located in LBNL Photo Lab Collection, XBD200506-00218-12). June 2005. DEEP TUNNEL INTO FOUNDATION UNDER BEVATRON, VIEW OF CART ON RAILS FOR TRANSPORTING EQUIPMENT - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  19. Identification and Quantification Soil Redoximorphic Features by Digital Image Processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil redoximorphic features (SRFs) have provided scientists and land managers with insight into relative soil moisture for approximately 60 years. The overall objective of this study was to develop a new method of SRF identification and quantification from soil cores using a digital camera and imag...

  20. Data Manipulation in an XML-Based Digital Image Library

    ERIC Educational Resources Information Center

    Chang, Naicheng

    2005-01-01

    Purpose: To help to clarify the role of XML tools and standards in supporting transition and migration towards a fully XML-based environment for managing access to information. Design/methodology/approach: The Ching Digital Image Library, built on a three-tier architecture, is used as a source of examples to illustrate a number of methods of data…

  1. Spectral reflectance and digital image relations among five aquatic weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study reports on the use of an artificial quartz halogen lighting source to facilitate the acquisition of spectral light reflectance measurements and digital imaging of invasive aquatic weeds. Spectral leaf or leaf/stem reflectance measurements were made on five aquatic weeds: Eurasian watermil...

  2. Digital Images: Capturing America's Past with the Technology of Today

    ERIC Educational Resources Information Center

    Berson, Michael J.

    2004-01-01

    The use of digital photography in the social studies classroom offers students an application of technology that can help them develop the skills necessary to access, analyze, and evaluate all forms of information and communication. Students learn to recognize how images represent diverse perspectives, connect disparate pieces of information, and…

  3. Using Digital Radiography To Image Liquid Nitrogen in Voids

    NASA Technical Reports Server (NTRS)

    Cox, Dwight; Blevins, Elana

    2007-01-01

    Digital radiography by use of (1) a field-portable x-ray tube that emits low-energy x rays and (2) an electronic imaging x-ray detector has been found to be an effective technique for detecting liquid nitrogen inside voids in thermal-insulation panels. The technique was conceived as a means of investigating cryopumping (including cryoingestion) as a potential cause of loss of thermal insulation foam from space-shuttle external fuel tanks. The technique could just as well be used to investigate cryopumping and cryoingestion in other settings. In images formed by use of low-energy x-rays, one can clearly distinguish between voids filled with liquid nitrogen and those filled with gaseous nitrogen or other gases. Conventional film radiography is of some value, but yields only non-real-time still images that do not show time dependences of levels of liquids in voids. In contrast, the present digital radiographic technique yields a succession of images in real time at a rate of about 10 frames per second. The digitized images can be saved for subsequent analysis to extract data on time dependencies of levels of liquids and, hence, of flow paths and rates of filling and draining. The succession of images also amounts to a real-time motion picture that can be used as a guide to adjustment of test conditions.

  4. Do we really need standards in digital image management?

    PubMed Central

    Ho, ELM

    2008-01-01

    Convention dictates that standards are a necessity rather than a luxury. Standards are supposed to improve the exchange of health and image data information resulting in improved quality and efficiency of patient care. True standardisation is some time away yet, as barriers exist with evolving equipment, storage formats and even the standards themselves. The explosive growth in the size and complexity of images such as those generated by multislice computed tomography have driven the need for digital image management, created problems of storage space and costs, and created a challenge for increasing or getting an adequate speed for transmitting, accessing and retrieving the image data. The search for a suitable and practical format for storing the data without loss of information and medico-legal implications has become a necessity and a matter of ‘urgency’. Existing standards are either open or proprietary and must comply with local, regional or national laws. Currently there are the Picture Archiving and Communications System (PACS); Digital Imaging and Communications in Medicine (DICOM); Health Level 7 (HL7) and Integrating the Healthcare Enterprise (IHE). Issues in digital image management can be categorised as operational, procedural, technical and administrative. Standards must stay focussed on the ultimate goal – that is, improved patient care worldwide. PMID:21611012

  5. Image processing and classification procedures for analysis of sub-decimeter imagery acquired with an unmanned aircraft over arid rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using five centimeter resolution images acquired with an unmanned aircraft system (UAS), we developed and evaluated an image processing workflow that included the integration of resolution-appropriate field sampling, feature selection, object-based image analysis, and processing approaches for UAS i...

  6. Digitizing Images for Curriculum 21: Phase II.

    ERIC Educational Resources Information Center

    Walker, Alice D.

    Although visual databases exist for the study of art, architecture, geography, health care, and other areas, readily accessible sources of quality images are not available for engineering faculty interested in developing multimedia modules or for student projects. Presented here is a brief review of Phase I of the Engineering Visual Database…

  7. Real-time digital image enhancement

    NASA Technical Reports Server (NTRS)

    Woods, R. E.; Gonzalez, R. C.

    1981-01-01

    A programmable system for enhancing monocular and stereographic images at video rates is presented. The system provides both automatic and interactive enhancement modes based on histogram modification and intensity mapping techniques. Experimental results which illustrate enhancement capabilities under a variety of scene types and conditions are described.

  8. Radiological images on personal computers: introduction and fundamental principles of digital images.

    PubMed

    Gillespy, T; Rowberg, A H

    1993-05-01

    This series of articles will explore the issue related to displaying, manipulating, and analyzing radiological images on personal computers (PC). This first article discusses the digital image data file, standard PC graphic file formats, and various methods for importing radiological images into the PC. PMID:8334176

  9. Distributed image coding for digital image recovery from the print-scan channel.

    PubMed

    Samadani, Ramin; Mukherjee, Debargha

    2010-03-01

    A printed digital photograph is difficult to reuse because the digital information that generated the print may no longer be available. This paper describes a method for approximating the original digital image by combining a scan of the printed photograph with digital auxiliary information kept together with the print. We formulate and solve the approximation problem using a Wyner-Ziv coding framework. During encoding, the Wyner-Ziv auxiliary information consists of a small amount of digital data composed of a number of sampled luminance pixel blocks and a number of sampled color pixel values to enable subsequent accurate registration and color-reproduction during decoding. The registration and color information is augmented by an additional amount of digital data encoded using Wyner-Ziv coding techniques that recovers residual errors and lost high spatial frequencies. The decoding process consists of scanning the printed photograph, together with a two step decoding process. The first decoding step, using the registration and color auxiliary information, generates a side-information image which registers and color corrects the scanned image. The second decoding step uses the additional Wyner-Ziv layer together with the side-information image to provide a closer approximation of the original, reducing residual errors and restoring the lost high spatial frequencies. The experimental results confirm the reduced digital storage needs when the scanned print assists in the digital reconstruction.

  10. "The Rush of Images": A Research Report into Digital Editing and the Moving Image.

    ERIC Educational Resources Information Center

    Burn, Andrew; Brindley, Sue; Durran, James; Kelsall, Carol; Sweetlove, Jane; Tuohey, Caroline

    2001-01-01

    Describes an action research project on digital editing being carried out by a group of teachers. Evaluates a conceptual framework for editing digitized moving images, under three headings: literacies and communicative practices; creativity; and social roles and learning styles. Presents three teacher accounts of student projects involving digital…

  11. kV x-ray dual digital tomosynthesis for image guided lung SBRT

    NASA Astrophysics Data System (ADS)

    Partain, Larry; Boyd, Douglas; Kim, Namho; Hernandez, Andrew; Daly, Megan; Boone, John

    2016-03-01

    Two simulated sets of digital tomosynthesis images of the lungs, each acquired at a 90 degree angle from the other, with 19 projection images used for each set and SART iterative reconstructed, gives dual tomosynthesis slice image quality approaching that of spiral CT, and with a data acquisition time that is 3% of that of cone beam CT. This fast kV acquisition, should allow near real time tracking of lung tumors in patients receiving SBRT, based on a novel TumoTrakTM multi-source X-ray tube design. Until this TumoTrakTM prototype is completed over the next year, its projected performance was simulated from the DRR images created from a spiral CT data set from a lung cancer patient. The resulting dual digital tomosynthesis reconstructed images of the lung tumor were exceptional and approached that of the gold standard Feldkamp CT reconstruction of breath hold, diagnostic, spiral, multirow, CT data. The relative dose at 46 mAs was less than 10% of what it would have been if the digital tomosynthesis had been done at the 472 mAs of the CT data set. This is for a 0.77 fps imaging rate sufficient to resolve respiratory motion in many free breathing patients during SBRT. Such image guidance could decrease the magnitudes of targeting error margins by as much as 20 mm or more in the craniocaudal direction for lower lobe lesions while markedly reducing dose to normal lung, heart and other critical structures. These initial results suggest a wide range of topics for future work.

  12. Digital image processing of vascular angiograms

    NASA Technical Reports Server (NTRS)

    Selzer, R. H.; Blankenhorn, D. H.; Beckenbach, E. S.; Crawford, D. W.; Brooks, S. H.

    1975-01-01

    A computer image processing technique was developed to estimate the degree of atherosclerosis in the human femoral artery. With an angiographic film of the vessel as input, the computer was programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge information and others from optical density variations within the lumen shadow. These measurements were combined into an atherosclerosis index, which was found to correlate well with both visual and chemical estimates of atherosclerotic disease.

  13. Autocorrelation and regularization in digital images. II - Simple image models

    NASA Technical Reports Server (NTRS)

    Jupp, David L. B.; Strahler, Alan H.; Woodcock, Curtis E.

    1989-01-01

    The variogram function used in geostatistical analysis is a useful statistic in the analysis of remotely sensed images. Using the results derived by Jupp et al. (1988), the basic second-order, or covariance, properties of scenes modeled by simple disks of varying size and spacing after imaging into disk-shaped pixels are analyzed to explore the relationship betwee image variograms and discrete object scene structure. The models provide insight into the nature of real images of the earth's surface and the tools for a complete analysis of the more complex case of three-dimensional illuminated discrete-object images.

  14. Recording multiple spatially-heterodyned direct to digital holograms in one digital image

    DOEpatents

    Hanson, Gregory R.; Bingham, Philip R.

    2008-03-25

    Systems and methods are described for recording multiple spatially-heterodyned direct to digital holograms in one digital image. A method includes digitally recording, at a first reference beam-object beam angle, a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram to sit on top of a first spatial-heterodyne carrier frequency defined by the first reference beam-object beam angle; digitally recording, at a second reference beam-object beam angle, a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram to sit on top of a second spatial-heterodyne carrier frequency defined by the second reference beam-object beam angle; applying a first digital filter to cut off signals around the first original origin and define a first result; performing a first inverse Fourier transform on the first result; applying a second digital filter to cut off signals around the second original origin and define a second result; and performing a second inverse Fourier transform on the second result, wherein the first reference beam-object beam angle is not equal to the second reference beam-object beam angle and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

  15. Digital Longitudinal Tomosynthesis

    NASA Astrophysics Data System (ADS)

    Rimkus, Daniel Steven

    1985-12-01

    The purpose of this dissertation was to investigate the clinical utility of digital longitudinal tomosynthesis in radiology. By acquiring a finite group of digital images during a longitudinal tomographic exposure, and processing these images, tomographic planes, other than the fulcrum plane, can be reconstructed. This process is now termed "tomosynthesis". A prototype system utilizing this technique was developed. Both phantom and patient studies were done with this system. The phantom studies were evaluated by subjective, visual criterion and by quantitative analysis of edge sharpness and noise in the reconstructions. Two groups of patients and one volunteer were studied. The first patient group consisted of 8 patients undergoing intravenous urography (IVU). These patients had digital tomography and film tomography of the abdomen. The second patient group consisted of 4 patients with lung cancer admitted to the hospital for laser resection of endobronchial tumor. These patients had mediastinal digital tomograms to evaluate the trachea and mainstem bronchi. The knee of one volunteer was imaged by film tomography and digital tomography. The results of the phantom studies showed that the digital reconstructions accurately produced images of the desired planes. The edge sharpness of the reconstructions approached that of the acquired images. Adequate reconstructions were achieved with as few as 5 images acquired during the exposure, with the quality of the reconstructions improving as the number of images acquired increased. The IVU patients' digital studies had less contrast and spatial resolution than the film tomograms. The single renal lesion visible on the film tomograms was also visible in the digital images. The digital mediastinal studies were felt by several radiologists to be superior to a standard chest xray in evaluating the airways. The digital images of the volunteer's knee showed many of the same anatomic features as the film tomogram, but the digital

  16. An automated digital imaging system for environmental monitoring applications

    USGS Publications Warehouse

    Bogle, Rian; Velasco, Miguel; Vogel, John

    2013-01-01

    Recent improvements in the affordability and availability of high-resolution digital cameras, data loggers, embedded computers, and radio/cellular modems have advanced the development of sophisticated automated systems for remote imaging. Researchers have successfully placed and operated automated digital cameras in remote locations and in extremes of temperature and humidity, ranging from the islands of the South Pacific to the Mojave Desert and the Grand Canyon. With the integration of environmental sensors, these automated systems are able to respond to local conditions and modify their imaging regimes as needed. In this report we describe in detail the design of one type of automated imaging system developed by our group. It is easily replicated, low-cost, highly robust, and is a stand-alone automated camera designed to be placed in remote locations, without wireless connectivity.

  17. Digital holographic optical coherence imaging of tumor tissue

    NASA Astrophysics Data System (ADS)

    Jeong, Kwan; Turek, John J.; Nolte, David D.

    2006-02-01

    Holographic Optical Coherence Imaging (OCI) uses spatial heterodyne detection in direct analogy with the temporal heterodyne detection of time-domain OCT. The spatial demodulator can be a sensitive dynamic holographic film or can be a CCD array placed directly at the hologram plane. We show that a digital hologram captured at the Fourier plane requires only a simple 2D inverse FFT of the digital hologram to compute the real image and its conjugate. Our recording on the optical Fourier plane has an advantage for diffuse targets because the intensity distribution of diffuse targets is relatively uniform at the Fourier plane and hence uses the full dynamic range of CCD camera. We applied this technique to human liver tumor spheroids and produced depth-resolved images to depth of 1.4 mm.

  18. Influence of imaging resolution on color fidelity in digital archiving.

    PubMed

    Zhang, Pengchang; Toque, Jay Arre; Ide-Ektessabi, Ari

    2015-11-01

    Color fidelity is of paramount importance in digital archiving. In this paper, the relationship between color fidelity and imaging resolution was explored by calculating the color difference of an IT8.7/2 color chart with a CIELAB color difference formula for scanning and simulation images. Microscopic spatial sampling was used in selecting the image pixels for the calculations to highlight the loss of color information. A ratio, called the relative imaging definition (RID), was defined to express the correlation between image resolution and color fidelity. The results show that in order for color differences to remain unrecognizable, the imaging resolution should be at least 10 times higher than the physical dimension of the smallest feature in the object being studied.

  19. Urban Object Extraction from Digital Surface Model and Digital Aerial Images

    NASA Astrophysics Data System (ADS)

    Grigillo, D.; Kanjir, U.

    2012-07-01

    The paper describes two different methods for extraction of two types of urban objects from lidar digital surface model (DSM) and digital aerial images. Within the preprocessing digital terrain model (DTM) and orthoimages for three test areas were generated from aerial images using automatic photogrammetric methods. Automatic building extraction was done using DSM and multispectral orthoimages. First, initial building mask was created from the normalized digital surface model (nDSM), then vegetation was eliminated from the building mask using multispectral orthoimages. The final building mask was produced employing several morphological operations and buildings were vectorised using Hough transform. Automatic extraction of other green urban features (trees and natural ground) started from orthoimages using iterative object-based classification. This method required careful selection of segmentation parameters; in addition to basic spectral bands also information from nDSM was included. After the segmentation of images the segments were classified based on their attributes (spatial, spectral, geometrical, texture) using rule set classificator. First iteration focused on visible (i.e. unshaded) urban features, and second iteration on objects in deep shade. Results from both iterations were merged into appropriate classes. Evaluation of the final results (completeness, correctness and quality) was carried out on a per-area level and on a per-object level by ISPRS Commission III, WG III/4.

  20. The trustworthy digital camera: Restoring credibility to the photographic image

    NASA Astrophysics Data System (ADS)

    Friedman, Gary L.

    1994-02-01

    The increasing sophistication of computers has made digital manipulation of photographic images, as well as other digitally-recorded artifacts such as audio and video, incredibly easy to perform and increasingly difficult to detect. Today, every picture appearing in newspapers and magazines has been digitally altered to some degree, with the severity varying from the trivial (cleaning up 'noise' and removing distracting backgrounds) to the point of deception (articles of clothing removed, heads attached to other people's bodies, and the complete rearrangement of city skylines). As the power, flexibility, and ubiquity of image-altering computers continues to increase, the well-known adage that 'the photography doesn't lie' will continue to become an anachronism. A solution to this problem comes from a concept called digital signatures, which incorporates modern cryptographic techniques to authenticate electronic mail messages. 'Authenticate' in this case means one can be sure that the message has not been altered, and that the sender's identity has not been forged. The technique can serve not only to authenticate images, but also to help the photographer retain and enforce copyright protection when the concept of 'electronic original' is no longer meaningful.

  1. The trustworthy digital camera: Restoring credibility to the photographic image

    NASA Technical Reports Server (NTRS)

    Friedman, Gary L.

    1994-01-01

    The increasing sophistication of computers has made digital manipulation of photographic images, as well as other digitally-recorded artifacts such as audio and video, incredibly easy to perform and increasingly difficult to detect. Today, every picture appearing in newspapers and magazines has been digitally altered to some degree, with the severity varying from the trivial (cleaning up 'noise' and removing distracting backgrounds) to the point of deception (articles of clothing removed, heads attached to other people's bodies, and the complete rearrangement of city skylines). As the power, flexibility, and ubiquity of image-altering computers continues to increase, the well-known adage that 'the photography doesn't lie' will continue to become an anachronism. A solution to this problem comes from a concept called digital signatures, which incorporates modern cryptographic techniques to authenticate electronic mail messages. 'Authenticate' in this case means one can be sure that the message has not been altered, and that the sender's identity has not been forged. The technique can serve not only to authenticate images, but also to help the photographer retain and enforce copyright protection when the concept of 'electronic original' is no longer meaningful.

  2. [Digital library for archiving files of radiology and medical imaging].

    PubMed

    Duvauferrier, R; Rambeau, M; Moulène, F

    1993-01-01

    The Conseil des Enseignants de Radiologie de France in collaboration with the Ilab-TSI company and Schering laboratories has developed a computer programme allowing the storage and consultation of radiological teaching files. This programme, developed on Macintosh from standard Hypercard and Quicktime applications, allows, in consultation mode, the multicriteria search and visualisation of selected radiological files. In the author mode, new files can be included after digitalizing the author's own images or after obtaining images from another image library. This programme, which allows juxtaposition of digitalised radiological files, is designed to be extremely open and can be easily combined with other computer-assisted teaching or computer-assisted presentation applications.

  3. Preliminary study of digital image correlation based optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Sun, Cuiru; Vuong, Barry; Wen, Xiao-Yan; Yang, Victor

    2013-06-01

    Optical coherence elastography (OCE) provides deformation or material properties mapping of soft tissue, which is important for morphological and pathological studies of the tissue. An OCE technique is developed based on digital image correlation. System calibration and measurement error evaluation are performed. The displacement measurement of 0.6 μm to over 100 μm was obtained through a phantom experiment. The capability of this OCE technique for differentiation of stiffness was evaluated by imaging a two-components phantom. OCE imaging of an aneurysm sample shows promising results for characterization of composites of aneurismal wall in the future.

  4. Image/video encryption using single shot digital holography

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyu; Tang, Chen; Zhu, Xinjun; Li, Biyuan; Wang, Linlin; Yan, Xiusheng

    2015-05-01

    We propose a method for image/video encryption that combines double random-phase encoding in the Fresnel domain with a single shot digital holography. In this method, a complex object field can be reconstructed with only single frame hologram based on a constrained optimization method. The system without multiple shots and Fourier lens is simple, and allows to dynamically encrypt information. We test the proposed method on a computer simulated image, a grayscale image and a video in AVI format. Also we investigate the quality of the decryption process and the performance against noise attacks. The experimental results demonstrate the performance of the method.

  5. Capturing Micro-topography of an Arctic Tundra Landscape through Digital Elevation Models (DEMs) Acquired from Various Remote Sensing Platforms

    NASA Astrophysics Data System (ADS)

    Vargas, S. A., Jr.; Tweedie, C. E.; Oberbauer, S. F.

    2013-12-01

    The need to improve the spatial and temporal scaling and extrapolation of plot level measurements of ecosystem structure and function to the landscape level has been identified as a persistent research challenge in the arctic terrestrial sciences. Although there has been a range of advances in remote sensing capabilities on satellite, fixed wing, helicopter and unmanned aerial vehicle platforms over the past decade, these present costly, logistically challenging (especially in the Arctic), technically demanding solutions for applications in an arctic environment. Here, we present a relatively low cost alternative to these platforms that uses kite aerial photography (KAP). Specifically, we demonstrate how digital elevation models (DEMs) were derived from this system for a coastal arctic landscape near Barrow, Alaska. DEMs of this area acquired from other remote sensing platforms such as Terrestrial Laser Scanning (TLS), Airborne Laser Scanning, and satellite imagery were also used in this study to determine accuracy and validity of results. DEMs interpolated using the KAP system were comparable to DEMs derived from the other platforms. For remotely sensing acre to kilometer square areas of interest, KAP has proven to be a low cost solution from which derived products that interface ground and satellite platforms can be developed by users with access to low-tech solutions and a limited knowledge of remote sensing.

  6. Applications of digital image analysis capability in Idaho

    NASA Technical Reports Server (NTRS)

    Johnson, K. A.

    1981-01-01

    The use of digital image analysis of LANDSAT imagery in water resource assessment is discussed. The data processing systems employed are described. The determination of urban land use conversion of agricultural land in two southwestern Idaho counties involving estimation and mapping of crop types and of irrigated land is described. The system was also applied to an inventory of irrigated cropland in the Snake River basin and establishment of a digital irrigation water source/service area data base for the basin. Application of the system to a determination of irrigation development in the Big Lost River basin as part of a hydrologic survey of the basin is also described.

  7. On the detection of pornographic digital images

    NASA Astrophysics Data System (ADS)

    Schettini, Raimondo; Brambilla, Carla; Cusano, Claudio; Ciocca, Gianluigi

    2003-06-01

    The paper addresses the problem of distinguishing between pornographic and non-pornographic photographs, for the design of semantic filters for the web. Both, decision forests of trees built according to CART (Classification And Regression Trees) methodology and Support Vectors Machines (SVM), have been used to perform the classification. The photographs are described by a set of low-level features, features that can be automatically computed simply on gray-level and color representation of the image. The database used in our experiments contained 1500 photographs, 750 of which labeled as pornographic on the basis of the independent judgement of several viewers.

  8. Three-dimensional imaging characteristics and depth resolution in digital holographic three-dimensional imaging spectrometry

    NASA Astrophysics Data System (ADS)

    Obara, Masaki; Yoshimori, Kyu

    2015-07-01

    A four-dimensional impulse response function for the digital holographic three-dimensional imaging spectrometry has been fully derived in closed form. Due to its factorizing nature of the mathematical expression of four-dimensional impulse response function, three-dimensional spatial part of impulse response function directly corresponds to threedimensional point spread function of in-line digital holography with rectangular aperture. Based on these mathematical results, this paper focuses on the investigation of spectral resolution and three-dimensional spatial resolution in digital holographic three-dimensional imaging spectrometry and digital holography. We found that the theoretical prediction agree well with the experimental results. This work suggests a new criterion and estimate method regarding threedimensional spatial resolution of in-line digital holography.

  9. Mars Orbiter Camera Acquires High Resolution Stereoscopic Images of the Viking One Landing Site

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Two MOC images of the vicinity of the Viking Lander 1 (MOC 23503 and 25403), acquired separately on 12 April 1998 at 08:32 PDT and 21 April 1998 at 13:54 PDT (respectively), are combined here in a stereoscopic anaglyph. The more recent, slightly better quality image is in the red channel, while the earlier image is shown in the blue and green channels. Only the overlap portion of the images is included in the composite.

    Image 23503 was taken at a viewing angle of 31.6o from vertical; 25403 was taken at an angle of 22.4o, for a difference of 9.4o. Although this is not as large a difference as is typically used in stereo mapping, it is sufficient to provide some indication of relief, at least in locations of high relief.

    The image shows the raised rims and deep interiors of the larger impact craters in the area (the largest crater is about 650 m/2100 feet across). It shows that the relief on the ridges is very subtle, and that, in general, the Viking landing site is very flat. This result is, of course, expected: the VL-1 site was chosen specifically because it was likely to have low to very low slopes that represented potential hazards to the spacecraft.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  10. Utilizing ultrasound as a surface digitization tool in image guided liver surgery

    NASA Astrophysics Data System (ADS)

    Miller, Kristen E.; Ondrake, Janet E.; Pheiffer, Thomas S.; Simpson, Amber L.; Miga, Michael I.

    2012-02-01

    Intraoperative ultrasound imaging is a commonly used modality for image guided surgery and can be used to monitor changes from pre-operative data in real time. Often a mapping of the liver surface is required to achieve image-tophysical alignment for image guided liver surgery. Laser range scans and tracked optical stylus instruments have both been utilized in the past to create an intraoperative representation of the organ surface. This paper proposes a method to digitize the organ surface utilizing tracked ultrasound and to evaluate a relatively simple correction technique. Surfaces are generated from point clouds obtained from the US transducer face itself during tracked movement. In addition, a surface generated from a laser range scan (LRS) was used as the gold standard for evaluating the accuracy of the US transducer swab surfaces. Two liver phantoms with varying stiffness were tested. The results reflected that the average deformation observed for a 60 second swab of the liver phantom was 3.7 +/- 0.9 mm for the more rigid phantom and 4.6 +/- 1.2 mm for the less rigid phantom. With respect to tissue targets below the surface, the average error in position due to ultrasound surface digitization was 3.5 +/- 0.5 mm and 5.9 +/- 0.9 mm for the stiffer and softer phantoms respectively. With the simple correction scheme, the surface error was reduced to 1.1 +/- 0.8 mm and 1.7 +/- 1.0 mm, respectively; and the subsurface target error was reduced to 2.0 +/- 0.9 mm and 4.5 +/- 1.8 mm, respectively. These results are encouraging and suggest that the ultrasound probe itself and the acquired images could serve as a comprehensive digitization approach for image guided liver surgery.

  11. Review of digital image security in Dermatology.

    PubMed

    Nielson, Colton; West, Cameron; Shimizu, Ikue

    2015-10-16

    The inherently visual nature of dermatology naturally lends itself to photography. As technology has evolved, smartphone cameras have become ubiquitous and have the potential to improve education and patient care in dermatology. Although patients and physicians may agree that photography can improve patient care, there are certain risks involved with smartphone photography in the medical field. Perhaps most concerning is the number of dermatologists using smartphones to take unsecured images in their daily practice. A recent study revealed that 22% of surveyed dermatologists used smartphone cameras multiple times per day in their practice. Dermatologists may also overestimate patient comfort with smartphone use in clinical photography. We present a review of the use of smartphones in dermatology and address the potential lack of security and accompanying ethical dilemmas.

  12. Review of digital image security in Dermatology.

    PubMed

    Nielson, Colton; West, Cameron; Shimizu, Ikue

    2015-10-01

    The inherently visual nature of dermatology naturally lends itself to photography. As technology has evolved, smartphone cameras have become ubiquitous and have the potential to improve education and patient care in dermatology. Although patients and physicians may agree that photography can improve patient care, there are certain risks involved with smartphone photography in the medical field. Perhaps most concerning is the number of dermatologists using smartphones to take unsecured images in their daily practice. A recent study revealed that 22% of surveyed dermatologists used smartphone cameras multiple times per day in their practice. Dermatologists may also overestimate patient comfort with smartphone use in clinical photography. We present a review of the use of smartphones in dermatology and address the potential lack of security and accompanying ethical dilemmas. PMID:26632792

  13. Frame Your Images: Making Digital Images Accessible for Study & Testing

    ERIC Educational Resources Information Center

    Gepner, Ivan

    2009-01-01

    Images, whether at the level of molecules, cells, organs, organisms, or environments, are at the core of many biological disciplines. Even with the contemporary emphasis on molecular analysis, biology has retained its traditional strong visual component. In courses that rely on the study of biological structure, the presentation of images for…

  14. The influence of hologram aperture on speckle noise in the reconstructed image of digital holography and its reduction

    NASA Astrophysics Data System (ADS)

    Cai, Xiao-ou; Wang, Hui

    2008-01-01

    Based on the whole process of the recording and reconstruction of digital holography, we study the formation cause of speckle noise in its reconstructed image and acquire the conclusion that the small size of hologram aperture diffraction aggravates the speckle noise of reconstructed image and the speckle noise has been one of primary noise sources in the reconstruction process. In order to reduce the speckle noise resulting from little hologram aperture diffraction, we set an appropriate aperture function matching the recording parameter and aperture size of hologram and deconvolve the reconstructed image with it. The validity has been proved in theory and experiment. Therefore, it offers a brand-new thought and practical way to reduce the speckle noise in the reconstructed image of digital holography.

  15. A Review of Digital Image Correlation Applied to Structura Dynamics

    NASA Astrophysics Data System (ADS)

    Niezrecki, Christopher; Avitabile, Peter; Warren, Christopher; Pingle, Pawan; Helfrick, Mark

    2010-05-01

    A significant amount of interest exists in performing non-contacting, full-field surface velocity measurement. For many years traditional non-contacting surface velocity measurements have been made by using scanning Doppler laser vibrometry, shearography, pulsed laser interferometry, pulsed holography, or an electronic speckle pattern interferometer (ESPI). Three dimensional (3D) digital image correlation (DIC) methods utilize the alignment of a stereo pair of images to obtain full-field geometry data, in three dimensions. Information about the change in geometry of an object over time can be found by comparing a sequence of images and virtual strain gages (or position sensors) can be created over the entire visible surface of the object of interest. Digital imaging techniques were first developed in the 1980s but the technology has only recently been exploited in industry and research due to the advances of digital cameras and personal computers. The use of DIC for structural dynamic measurement has only very recently been investigated. Within this paper, the advantages and limits of using DIC for dynamic measurement are reviewed. Several examples of using DIC for dynamic measurement are presented on several vibrating and rotating structures.

  16. Color calibration of swine gastrointestinal tract images acquired by radial imaging capsule endoscope

    NASA Astrophysics Data System (ADS)

    Ou-Yang, Mang; Jeng, Wei-De; Lai, Chien-Cheng; Wu, Hsien-Ming; Lin, Jyh-Hung

    2016-01-01

    The type of illumination systems and color filters used typically generate varying levels of color difference in capsule endoscopes, which influence medical diagnoses. In order to calibrate the color difference caused by the optical system, this study applied a radial imaging capsule endoscope (RICE) to photograph standard color charts, which were then employed to calculate the color gamut of RICE. Color gamut was also measured using a spectrometer in order to get a high-precision color information, and the results obtained using both methods were compared. Subsequently, color-correction methods, namely polynomial transform and conformal mapping, were used to improve the color difference. Before color calibration, the color difference value caused by the influences of optical systems in RICE was 21.45±1.09. Through the proposed polynomial transformation, the color difference could be reduced effectively to 1.53±0.07. Compared to another proposed conformal mapping, the color difference value was substantially reduced to 1.32±0.11, and the color difference is imperceptible for human eye because it is <1.5. Then, real-time color correction was achieved using this algorithm combined with a field-programmable gate array, and the results of the color correction can be viewed from real-time images.

  17. Integrated terrain mapping with digital Landsat images in Queensland, Australia

    USGS Publications Warehouse

    Robinove, Charles Joseph

    1979-01-01

    Mapping with Landsat images usually is done by selecting single types of features, such as soils, vegetation, or rocks, and creating visually interpreted or digitally classified maps of each feature. Individual maps can then be overlaid on or combined with other maps to characterize the terrain. Integrated terrain mapping combines several terrain features into each map unit which, in many cases, is more directly related to uses of the land and to methods of land management than the single features alone. Terrain brightness, as measured by the multispectral scanners in Landsat 1 and 2, represents an integration of reflectance from the terrain features within the scanner's instantaneous field of view and is therefore more correlatable with integrated terrain units than with differentiated ones, such as rocks, soils, and vegetation. A test of the feasibilty of the technique of mapping integrated terrain units was conducted in a part of southwestern Queensland, Australia, in cooperation with scientists of the Queensland Department of Primary Industries. The primary purpose was to test the use of digital classification techniques to create a 'land systems map' usable for grazing land management. A recently published map of 'land systems' in the area (made by aerial photograph interpretation and ground surveys), which are integrated terrain units composed of vegetation, soil, topography, and geomorphic features, was used as a basis for comparison with digitally classified Landsat multispectral images. The land systems, in turn, each have a specific grazing capacity for cattle (expressed in beasts per km 2 ) which is estimated following analysis of both research results and property carrying capacities. Landsat images, in computer-compatible tape form, were first contrast-stretched to increase their visual interpretability, and digitally classified by the parallelepiped method into distinct spectral classes to determine their correspondence to the land systems classes and

  18. Forensic detection of noise addition in digital images

    NASA Astrophysics Data System (ADS)

    Cao, Gang; Zhao, Yao; Ni, Rongrong; Ou, Bo; Wang, Yongbin

    2014-03-01

    We proposed a technique to detect the global addition of noise to a digital image. As an anti-forensics tool, noise addition is typically used to disguise the visual traces of image tampering or to remove the statistical artifacts left behind by other operations. As such, the blind detection of noise addition has become imperative as well as beneficial to authenticate the image content and recover the image processing history, which is the goal of general forensics techniques. Specifically, the special image blocks, including constant and strip ones, are used to construct the features for identifying noise addition manipulation. The influence of noising on blockwise pixel value distribution is formulated and analyzed formally. The methodology of detectability recognition followed by binary decision is proposed to ensure the applicability and reliability of noising detection. Extensive experimental results demonstrate the efficacy of our proposed noising detector.

  19. Optical Synchrotron Radiation Beam Imaging with a Digital Mask

    SciTech Connect

    Fiorito, R. B.; Zhang, H. D.; Corbett, W. J.; Fisher, A. S.; Mok, W. Y.; Tian, K.; Douglas, D.; Wilson, F. G.; Zhang, S.; Mitsuhashi, T. M.; Shkvarunets, A. G.

    2012-11-01

    We have applied a new imaging/optical masking technique, which employs a digital micro-mirror device (DMD) and optical synchrotron radiation (OSR), to perform high dynamic range (DR) beam imaging at the JLAB Energy Recovery Linac and the SLAC/SPEAR3 Synchrotron Light Source. The OSR from the beam is first focused onto the DMD to produce a primary image; selected areas of this image are spatially filtered by controlling the state of individual micro-mirrors; and finally, the filtered image is refocused onto a CCD camera. At JLAB this technique has been used successfully to view the beam halo with a DR ~ 105. At SPEAR3 the DMD was used to filter out the bright core of the stored beam to study the turn-by-turn dynamics of the 10-3 weaker injected beam. We describe the optical performance, present limitations and our plans to improve the DR of both experimental systems.

  20. Synthesis of color filter array pattern in digital images

    NASA Astrophysics Data System (ADS)

    Kirchner, Matthias; Böhme, Rainer

    2009-02-01

    We propose a method to synthetically create or restore typical color filter array (CFA) pattern in digital images. This can be useful, inter alia, to conceal traces of manipulation from forensic techniques that analyze the CFA structure of images. For continuous signals, our solution maintains optimal image quality, using a quadratic cost function; and it can be computed efficiently. Our general approach allows to derive even more efficient approximate solutions that achieve linear complexity in the number of pixels. The effectiveness of the CFA synthesis as tamper-hiding technique and its superior image quality is backed with experimental evidence on large image sets and against state-of-the-art forensic techniques. This exposition is confined to the most relevant 'Bayer'-grid, but the method can be generalized to other layouts as well.

  1. Digital spectral imaging for histopathology and cytopathology

    NASA Astrophysics Data System (ADS)

    Levenson, Richard M.; Farkas, Daniel L.

    1997-05-01

    The process by which diseases, particularly neoplastic diseases, are diagnosed by pathologists using microscopic evaluation of tissue has changed little over the last several decades despite the advent of molecular medicine. Cells or tissues, stained with complex and sometimes poorly characterized organic dyes, are examined using a subjective, pattern-matching approach whose accuracy and reproducibility has increasingly been challenged. Furthermore, the ability of pathologists to deliver accurate prognoses using histological and clinical parameters remains limited, leading to both over- and under-treatment. While molecular techniques hold out great promise as diagnostic and prognostic tools, they are currently still largely investigational, and costly. A complementary approach is proposed, whereby more information is obtained by improved analysis of conventionally prepared histological and cytological samples. Using inverse Fourier transform multi- pixel spectroscopy, a new instrument has been developed which can display a complete transmittance or emission spectrum at every pixel of an image, providing much more color information than can be appreciated by eye or by conventional red-green-blue color cameras. Since spectra variations in staining behavior correlate with alterations in subcellular macromolecular composition it seems likely that they may also correlate with diagnosis and clinical behavior for a number of disease states. Examples of how this approach may prove useful in clinical practice are provided.

  2. Development of a digital receiver for range imaging atmospheric radar

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masayuki K.; Fujita, Toshiyuki; Abdul Aziz, Noor Hafizah Binti; Gan, Tong; Hashiguchi, Hiroyuki; Yu, Tian-You; Yamamoto, Mamoru

    2014-10-01

    In this paper, we describe a new digital receiver developed for a 1.3-GHz range imaging atmospheric radar. The digital receiver comprises a general-purpose software-defined radio receiver referred to as the Universal Software Radio Peripheral 2 (USRP2) and a commercial personal computer (PC). The receiver is designed to collect received signals at an intermediate frequency (IF) of 130 MHz with a sample rate of 10 MS s-1. The USRP2 digitizes IF received signals, produces IQ time series, and then transfers the IQ time series to the PC through Gigabit Ethernet. The PC receives the IQ time series, performs range sampling, carries out filtering in the range direction, decodes the phase-modulated received signals, integrates the received signals in time, and finally saves the processed data to the hard disk drive (HDD). Because only sequential data transfer from the USRP2 to the PC is available, the range sampling is triggered by transmitted pulses leaked to the receiver. For range imaging, the digital receiver performs real-time signal processing for each of the time series collected at different frequencies. Further, the receiver is able to decode phase-modulated oversampled signals. Because the program code for real-time signal processing is written in a popular programming language (C++) and widely used libraries, the signal processing is easy to implement, reconfigure, and reuse. From radar experiments using a 1-μs subpulse width and 1-MHz frequency span (i.e., 2-MHz frequency bandwidth), we demonstrate that range imaging in combination with oversampling, which was implemented for the first time by the digital receiver, is able to resolve the fine-scale structure of turbulence with a vertical scale as small as 100 m or finer.

  3. IMAGEP - A FORTRAN ALGORITHM FOR DIGITAL IMAGE PROCESSING

    NASA Technical Reports Server (NTRS)

    Roth, D. J.

    1994-01-01

    IMAGEP is a FORTRAN computer algorithm containing various image processing, analysis, and enhancement functions. It is a keyboard-driven program organized into nine subroutines. Within the subroutines are other routines, also, selected via keyboard. Some of the functions performed by IMAGEP include digitization, storage and retrieval of images; image enhancement by contrast expansion, addition and subtraction, magnification, inversion, and bit shifting; display and movement of cursor; display of grey level histogram of image; and display of the variation of grey level intensity as a function of image position. This algorithm has possible scientific, industrial, and biomedical applications in material flaw studies, steel and ore analysis, and pathology, respectively. IMAGEP is written in VAX FORTRAN for DEC VAX series computers running VMS. The program requires the use of a Grinnell 274 image processor which can be obtained from Mark McCloud Associates, Campbell, CA. An object library of the required GMR series software is included on the distribution media. IMAGEP requires 1Mb of RAM for execution. The standard distribution medium for this program is a 1600 BPI 9track magnetic tape in VAX FILES-11 format. It is also available on a TK50 tape cartridge in VAX FILES-11 format. This program was developed in 1991. DEC, VAX, VMS, and TK50 are trademarks of Digital Equipment Corporation.

  4. Scanned well-log image and digital data management

    SciTech Connect

    Zainalabedin, K.A.; Derr, M.E.; Fenn, C.J.

    1995-08-01

    As part of a comprehensive, multidisciplinary data-management project, libraries of computer-archived well logs that provide access to both scanned-image and digitized-curve data are under development. A comprehensive set of retrieval and management tools facilitates log-image and digitized-curve access and use. Images are accessible for viewing on Unix workstation and mainframe terminals at all office locations and also may be plotted as hard-copy paper prints. Network connectivity and file sharing also facilitate transfer to workstation analytical software. By using the central mainframe as a library and catalog manager, mass storage and database-intensive management tasks are handled outside of the Unix networks. Independence from the rapidly developing workstation network environment reduces database maintenance and permits longer-term data management planning than would otherwise be practical. Image libraries are a development step in a trend toward an image-based work environment in which well-log and other geotechnical image data are expected to become primary analytical resources.

  5. Scanned well log image and digital curve management

    SciTech Connect

    Zainalabedin, K.A.; Derr, M.E.; Fenn, C.J.

    1994-12-31

    As part of a comprehensive, multi-disciplinary data management project, libraries of computer archived well logs are under development which provide access to both scanned image and digitized curve data. A comprehensive set of retrieval and management tools facilitate log image and digitized curve access and utilization. Images are accessible for viewing on UNIX workstation and mainframe terminals at all office locations, and may also be plotted as hardcopy paper prints. Network connectivity and file sharing also facilitate transfer to workstation analytical software. By utilizing the central mainframe as a library and catalog manager, mass storage and database-intensive management tasks are handled outside of the UNIX networks. Independence from the rapidly developing workstation network environment reduces database maintenance and permits longer-term data management planning than would otherwise be practical. Image libraries are a developmental step in a trend toward an image-based work environment in which well log and other geo-technical image data are expected to become primary analytical resources.

  6. Digital Pathology: Data-Intensive Frontier in Medical Imaging

    PubMed Central

    Cooper, Lee A. D.; Carter, Alexis B.; Farris, Alton B.; Wang, Fusheng; Kong, Jun; Gutman, David A.; Widener, Patrick; Pan, Tony C.; Cholleti, Sharath R.; Sharma, Ashish; Kurc, Tahsin M.; Brat, Daniel J.; Saltz, Joel H.

    2013-01-01

    Pathology is a medical subspecialty that practices the diagnosis of disease. Microscopic examination of tissue reveals information enabling the pathologist to render accurate diagnoses and to guide therapy. The basic process by which anatomic pathologists render diagnoses has remained relatively unchanged over the last century, yet advances in information technology now offer significant opportunities in image-based diagnostic and research applications. Pathology has lagged behind other healthcare practices such as radiology where digital adoption is widespread. As devices that generate whole slide images become more practical and affordable, practices will increasingly adopt this technology and eventually produce an explosion of data that will quickly eclipse the already vast quantities of radiology imaging data. These advances are accompanied by significant challenges for data management and storage, but they also introduce new opportunities to improve patient care by streamlining and standardizing diagnostic approaches and uncovering disease mechanisms. Computer-based image analysis is already available in commercial diagnostic systems, but further advances in image analysis algorithms are warranted in order to fully realize the benefits of digital pathology in medical discovery and patient care. In coming decades, pathology image analysis will extend beyond the streamlining of diagnostic workflows and minimizing interobserver variability and will begin to provide diagnostic assistance, identify therapeutic targets, and predict patient outcomes and therapeutic responses. PMID:25328166

  7. Fingerprint pattern restoration by digital image processing techniques.

    PubMed

    Wen, Che-Yen; Yu, Chiu-Chung

    2003-09-01

    Fingerprint evidence plays an important role in solving criminal problems. However, defective (lacking information needed for completeness) or contaminated (undesirable information included) fingerprint patterns make identifying and recognizing processes difficult. Unfortunately. this is the usual case. In the recognizing process (enhancement of patterns, or elimination of "false alarms" so that a fingerprint pattern can be searched in the Automated Fingerprint Identification System (AFIS)), chemical and physical techniques have been proposed to improve pattern legibility. In the identifying process, a fingerprint examiner can enhance contaminated (but not defective) fingerprint patterns under guidelines provided by the Scientific Working Group on Friction Ridge Analysis, Study and Technology (SWGFAST), the Scientific Working Group on Imaging Technology (SWGIT), and an AFIS working group within the National Institute of Justice. Recently, the image processing techniques have been successfully applied in forensic science. For example, we have applied image enhancement methods to improve the legibility of digital images such as fingerprints and vehicle plate numbers. In this paper, we propose a novel digital image restoration technique based on the AM (amplitude modulation)-FM (frequency modulation) reaction-diffusion method to restore defective or contaminated fingerprint patterns. This method shows its potential application to fingerprint pattern enhancement in the recognizing process (but not for the identifying process). Synthetic and real images are used to show the capability of the proposed method. The results of enhancing fingerprint patterns by the manual process and our method are evaluated and compared. PMID:14535661

  8. Shape determination of microcalcifications in simulated digital mammography images with varying pixel size

    NASA Astrophysics Data System (ADS)

    Ruschin, Mark; Bath, Magnus; Hemdal, Bengt; Tingberg, Anders

    2005-04-01

    The purpose of this work was to study how the pixel size of digital detectors can affect shape determination of microcalcifications in mammography. Screen-film mammograms containing microcalcifications clinically proven to be indicative of malignancy were digitised at 100 lines/mm using a high-resolution Tango drum scanner. Forty microcalcifications were selected to cover an appropriate range of sizes, shapes and contrasts typically found of malignant cases. Based on the measured MTF and NPS of the combined screen-film and scanner system, these digitised images were filtered to simulate images acquired with a square sampling pixel size of 10 μm x 10 μm and a fill factor of one. To simulate images acquired with larger pixel sizes, these finely sampled images were re-binned to yield a range of effective pixel sizes from 20 μm up to 140 μm. An alternative forced-choice (AFC) observer experiment was conducted with eleven observers for this set of digitised microcalcifications to determine how pixel size affects the ability to discriminate shape. It was found that observer score increased with decreasing pixel size down to 60 μm (p<0.01), at which point no significant advantage was obtained by using smaller pixel sizes due to the excessive relative noise-per-pixel. The relative gain in shape discrimination ability at smaller pixel sizes was larger for microcalcifications that were smaller than 500 μm and circular.

  9. Self-interference digital holographic microscopy for live cell imaging

    NASA Astrophysics Data System (ADS)

    Kemper, Björn; Dartmann, Sebastian; Schlichthaber, Frank; Vollmer, Angelika; Ketelhut, Steffi; von Bally, Gert

    2012-06-01

    Quantitative digital holographic multi-focus phase imaging enables label-free minimally invasive live cell analysis by high resolution detection of sample induced optical path length changes. However, a drawback of many experimental arrangements for the analysis of living cells with digital holography is the requirement for a separate reference wave which results in a phase stability decrease and the demand for a precise adjustment of the intensity ratio between object and reference wave. Thus, a self interference digital holographic microscopy (DHM) approach was explored which only requires a single object illumination wave. Due to the Michelson interferometer design of the proposed experimental setup two wave fronts with an almost identical curvature are superimposed. This results in a simplified evaluation of the digital holograms. The applicability of the proposed self interference principle is illustrated by results from a technical specimen and living single cells. Furthermore, adherent cancer cells have been analyzed for morphology changes in perfusion chambers due to flow and the refractive index of suspended cells was determined. In summary, the method prospects to be a versatile tool for quantitative phase imaging as simplification is important for the establishment of these methods in live cell analysis.

  10. Physical Activity Recognition Based on Motion in Images Acquired by a Wearable Camera.

    PubMed

    Zhang, Hong; Li, Lu; Jia, Wenyan; Fernstrom, John D; Sclabassi, Robert J; Mao, Zhi-Hong; Sun, Mingui

    2011-06-01

    A new technique to extract and evaluate physical activity patterns from image sequences captured by a wearable camera is presented in this paper. Unlike standard activity recognition schemes, the video data captured by our device do not include the wearer him/herself. The physical activity of the wearer, such as walking or exercising, is analyzed indirectly through the camera motion extracted from the acquired video frames. Two key tasks, pixel correspondence identification and motion feature extraction, are studied to recognize activity patterns. We utilize a multiscale approach to identify pixel correspondences. When compared with the existing methods such as the Good Features detector and the Speed-up Robust Feature (SURF) detector, our technique is more accurate and computationally efficient. Once the pixel correspondences are determined which define representative motion vectors, we build a set of activity pattern features based on motion statistics in each frame. Finally, the physical activity of the person wearing a camera is determined according to the global motion distribution in the video. Our algorithms are tested using different machine learning techniques such as the K-Nearest Neighbor (KNN), Naive Bayesian and Support Vector Machine (SVM). The results show that many types of physical activities can be recognized from field acquired real-world video. Our results also indicate that, with a design of specific motion features in the input vectors, different classifiers can be used successfully with similar performances.

  11. Physical Activity Recognition Based on Motion in Images Acquired by a Wearable Camera

    PubMed Central

    Zhang, Hong; Li, Lu; Jia, Wenyan; Fernstrom, John D.; Sclabassi, Robert J.; Mao, Zhi-Hong; Sun, Mingui

    2011-01-01

    A new technique to extract and evaluate physical activity patterns from image sequences captured by a wearable camera is presented in this paper. Unlike standard activity recognition schemes, the video data captured by our device do not include the wearer him/herself. The physical activity of the wearer, such as walking or exercising, is analyzed indirectly through the camera motion extracted from the acquired video frames. Two key tasks, pixel correspondence identification and motion feature extraction, are studied to recognize activity patterns. We utilize a multiscale approach to identify pixel correspondences. When compared with the existing methods such as the Good Features detector and the Speed-up Robust Feature (SURF) detector, our technique is more accurate and computationally efficient. Once the pixel correspondences are determined which define representative motion vectors, we build a set of activity pattern features based on motion statistics in each frame. Finally, the physical activity of the person wearing a camera is determined according to the global motion distribution in the video. Our algorithms are tested using different machine learning techniques such as the K-Nearest Neighbor (KNN), Naive Bayesian and Support Vector Machine (SVM). The results show that many types of physical activities can be recognized from field acquired real-world video. Our results also indicate that, with a design of specific motion features in the input vectors, different classifiers can be used successfully with similar performances. PMID:21779142

  12. Characterization of lead zirconate titanate microwires using digital image correlation

    NASA Astrophysics Data System (ADS)

    Malakooti, Mohammad H.; Miller, Alexander T.; Sodano, Henry A.

    2015-04-01

    Lead zirconate titanate (PZT) microwires with applications in sensors, actuators, and energy harvesters are produced using hydrothermal synthesis. The synthesized microwires are relatively large with an average length of about 450 microns and an average width of 4 microns. Each of these individual PZT microwires can be integrated in smart systems as an active phase or be used as an independent smart material. In this paper, the synthesis procedure and characterization of these large microwires is demonstrated. The converse piezoelectric properties of the microwires are measured using digital image correlation after clamping and adding electrodes at each end of the microwire. It has been shown in the literature that digital image correlation can be used as a precise tool for rapid characterization of piezoelectric materials. Here, it is demonstrated that this technique can be applied to characterize the actual response of piezoelectric materials at the micron scale.

  13. A robust chaotic algorithm for digital image steganography

    NASA Astrophysics Data System (ADS)

    Ghebleh, M.; Kanso, A.

    2014-06-01

    This paper proposes a new robust chaotic algorithm for digital image steganography based on a 3-dimensional chaotic cat map and lifted discrete wavelet transforms. The irregular outputs of the cat map are used to embed a secret message in a digital cover image. Discrete wavelet transforms are used to provide robustness. Sweldens' lifting scheme is applied to ensure integer-to-integer transforms, thus improving the robustness of the algorithm. The suggested scheme is fast, efficient and flexible. Empirical results are presented to showcase the satisfactory performance of our proposed steganographic scheme in terms of its effectiveness (imperceptibility and security) and feasibility. Comparison with some existing transform domain steganographic schemes is also presented.

  14. Speckle reduction in optical coherence tomography images using digital filtering

    PubMed Central

    Ozcan, Aydogan; Bilenca, Alberto; Desjardins, Adrien E.; Bouma, Brett E.; Tearney, Guillermo J.

    2009-01-01

    Speckle noise is a ubiquitous artifact that limits the interpretation of optical coherence tomography images. Here we apply various speckle-reduction digital filters to optical coherence tomography images and compare their performance. Our results indicate that shift-invariant, nonorthogonal wavelet-transform-based filters together with enhanced Lee and adaptive Wiener filters can significantly reduce speckle and increase the signal-to-noise ratio, while preserving strong edges. The speckle reduction capabilities of these filters are also compared with speckle reduction from incoherent angular compounding. Our results suggest that by using these digital filters, the number of individual angles required to attain a certain level of speckle reduction can be decreased. PMID:17728812

  15. Method for image quality monitoring on digital television networks

    NASA Astrophysics Data System (ADS)

    Bretillon, Pierre; Baina, Jamal; Jourlin, Michel; Goudezeune, Gabriel

    1999-11-01

    This paper presents a method designed to monitor image quality. The emphasis is given here to the monitoring in digital television broadcasting networks, in order for the providers to ensure a 'user-oriented' Quality of Service. Most objective image quality assessment methods are technically very difficult to apply in this context because of bandwidth limitations. We propose a parametric, reduced reference method that relies on the evaluation of characteristic coding and transmission impairments with a set of features. We show that quality can be predicted with a satisfying correlation to a subjective evaluation by the combination of several impairment features in an appropriate model. The method has been implemented and tested in a range of situations on simulated and real DVB networks. This allows to conclude on the usefulness of the approach and our future developments for quality of service monitoring in digital television.

  16. Digital-image processing and image analysis of glacier ice

    USGS Publications Warehouse

    Fitzpatrick, Joan J.

    2013-01-01

    This document provides a methodology for extracting grain statistics from 8-bit color and grayscale images of thin sections of glacier ice—a subset of physical properties measurements typically performed on ice cores. This type of analysis is most commonly used to characterize the evolution of ice-crystal size, shape, and intercrystalline spatial relations within a large body of ice sampled by deep ice-coring projects from which paleoclimate records will be developed. However, such information is equally useful for investigating the stress state and physical responses of ice to stresses within a glacier. The methods of analysis presented here go hand-in-hand with the analysis of ice fabrics (aggregate crystal orientations) and, when combined with fabric analysis, provide a powerful method for investigating the dynamic recrystallization and deformation behaviors of bodies of ice in motion. The procedures described in this document compose a step-by-step handbook for a specific image acquisition and data reduction system built in support of U.S. Geological Survey ice analysis projects, but the general methodology can be used with any combination of image processing and analysis software. The specific approaches in this document use the FoveaPro 4 plug-in toolset to Adobe Photoshop CS5 Extended but it can be carried out equally well, though somewhat less conveniently, with software such as the image processing toolbox in MATLAB, Image-Pro Plus, or ImageJ.

  17. Real-Time Digital Compression Of Television Image Data

    NASA Technical Reports Server (NTRS)

    Barnes, Scott P.; Shalkhauser, Mary JO; Whyte, Wayne A., Jr.

    1990-01-01

    Digital encoding/decoding system compresses color television image data in real time for transmission at lower data rates and, consequently, lower bandwidths. Implements predictive coding process, in which each picture element (pixel) predicted from values of prior neighboring pixels, and coded transmission expresses difference between actual and predicted current values. Combines differential pulse-code modulation process with non-linear, nonadaptive predictor, nonuniform quantizer, and multilevel Huffman encoder.

  18. Methods of Improving a Digital Image Having White Zones

    NASA Technical Reports Server (NTRS)

    Wodell, Glenn A. (Inventor); Jobson, Daniel J. (Inventor); Rahman, Zia-Ur (Inventor)

    2005-01-01

    The present invention is a method of processing a digital image that is initially represented by digital data indexed to represent positions on a display. The digital data is indicative of an intensity value I,(x,y) for each position (x,y) in each i-th spectral band. The intensity value for each position in each i-th spectral band is adjusted to generate an adjusted intensity value for each position in each i-th spectral band in accordance with SIGMA (sup N)(sub n=1)W(sub n)(log I(sub i)(x,y)-log[I(sub i)(x,y)*F(sub n)(x,y)]), i = 1,...,S where W(sub n) is a weighting factor, "*" is the convolution operator and S is the total number of unique spectral bands. For each n, the function F(sub n)(x,y) is a unique surround function applied to each position (x,y) and N is the total number of unique surround functions. Each unique surround function is scaled to improve some aspect of the digital image, e.g., dynamic range compression, color constancy, and lightness rendition. The adjusted intensity value for each position in each i-th spectral band of the image is then filtered with a filter function to generate a filtered intensity value R(sub i)(x,y). To Prevent graying of white zones in the image, the maximum of the original intensity value I(sub i)(x,y) and filtered intensity value R(sub i)(x,y) is selected for display.

  19. Digital TV image quality improvement considering distributions of edge characteristic

    NASA Astrophysics Data System (ADS)

    Hong, Sang-Gi; Kim, Jae-Chul; Park, Jong-Hyun

    2003-12-01

    Sharpness enhancement is widely used technique for improving the perceptual quality of an image by emphasizing its high-frequency component. In this paper, a psychophysical experiment is conducted by the 20 observers with simple linear unsharp masking for sharpness enhancement. The experimental result is extracted using z-score analysis and linear regression. Finally using this result we suggest observer preferable sharpness enhancement method for digital television.

  20. Encryption On Grayscale Image For Digital Image Confidentiality Using Shamir Secret Sharing Scheme

    NASA Astrophysics Data System (ADS)

    Rodiah; Anggraini, Dyah; Fitrianingsih; Kazhimi, Farizan

    2016-04-01

    The use of high-frequency internet in the process of exchanging information and digital transaction is often accompanied by transmitting digital image in the form of raster images. Secret sharing schemes are multiparty protocols that related to the key establishment which provides protection against any threats of losing cryptography key. The greater the key duplication, the higher the risk of losing the key and vice versa. In this study, Secret Sharing Method was used by employing Shamir Threshold Scheme Algorithm on grayscale digital image with the size of 256×256 pixel obtaining 128×128 pixels of shared image with threshold values (4, 8). The result number of shared images were 8 parts and the recovery process can be carried out by at least using 4 shares of the 8 parts. The result of encryption on grayscale image is capable of producing vague shared image (i.e., no perceptible information), therefore a message in the form of digital image can be kept confidential and secure.

  1. Pitch evaluation of gratings based on a digital image correlation technique

    NASA Astrophysics Data System (ADS)

    Lu, Yancong; Jia, Wei; Wei, Chunlong; Yu, Junjie; Li, Shubin; Li, Yanyang; Li, Minkang; Qiu, Jucheng; Wang, Shaoqing; Zhou, Changhe

    2016-04-01

    The digital image correlation (DIC) technique used for metrological grating evaluation is presented in this paper. A CCD camera is used to acquire the grating image, and the DIC technique together with the peak-position detection method is used to evaluate the grating pitches. The theoretical analysis and simulations are performed to confirm that the performance of our technique is as accurate as the Fourier transform (FT) technique, and is capable of noise resistance. As an example, the uniformity of the grating fabricated in our laboratory is measured using this method. The experimental results show that this grating has a peak-to-valley uniformity of 48 nm during a long range of 35 mm, and our technique has a higher repeatability than the FT technique in our measurement strategy. This work should be of great significance for the evaluation of metrological grating for optical encoders.

  2. Improving depth resolution in digital breast tomosynthesis by iterative image reconstruction

    NASA Astrophysics Data System (ADS)

    Roth, Erin G.; Kraemer, David N.; Sidky, Emil Y.; Reiser, Ingrid S.; Pan, Xiaochuan

    2015-03-01

    Digital breast tomosynthesis (DBT) is currently enjoying tremendous growth in its application to screening for breast cancer. This is because it addresses a major weakness of mammographic projection imaging; namely, a cancer can be hidden by overlapping fibroglandular tissue structures or the same normal structures can mimic a malignant mass. DBT addresses these issues by acquiring few projections over a limited angle scanning arc that provides some depth resolution. As DBT is a relatively new device, there is potential to improve its performance significantly with improved image reconstruction algorithms. Previously, we reported a variation of adaptive steepest descent - projection onto convex sets (ASD-POCS) for DBT, which employed a finite differencing filter to enhance edges for improving visibility of tissue structures and to allow for volume-of-interest reconstruction. In the present work we present a singular value decomposition (SVD) analysis to demonstrate the gain in depth resolution for DBT afforded by use of the finite differencing filter.

  3. A Low Power Digital Accumulation Technique for Digital-Domain CMOS TDI Image Sensor.

    PubMed

    Yu, Changwei; Nie, Kaiming; Xu, Jiangtao; Gao, Jing

    2016-01-01

    In this paper, an accumulation technique suitable for digital domain CMOS time delay integration (TDI) image sensors is proposed to reduce power consumption without degrading the rate of imaging. In terms of the slight variations of quantization codes among different pixel exposures towards the same object, the pixel array is divided into two groups: one is for coarse quantization of high bits only, and the other one is for fine quantization of low bits. Then, the complete quantization codes are composed of both results from the coarse-and-fine quantization. The equivalent operation comparably reduces the total required bit numbers of the quantization. In the 0.18 µm CMOS process, two versions of 16-stage digital domain CMOS TDI image sensor chains based on a 10-bit successive approximate register (SAR) analog-to-digital converter (ADC), with and without the proposed technique, are designed. The simulation results show that the average power consumption of slices of the two versions are 6 . 47 × 10 - 8 J/line and 7 . 4 × 10 - 8 J/line, respectively. Meanwhile, the linearity of the two versions are 99.74% and 99.99%, respectively. PMID:27669256

  4. A community-based urban forest inventory using online mapping services and consumer-grade digital images

    NASA Astrophysics Data System (ADS)

    Abd-Elrahman, Amr H.; Thornhill, Mary E.; Andreu, Michael G.; Escobedo, Francisco

    2010-08-01

    Community involvement in gathering and submitting spatially referenced data via web mapping applications has recently been gaining momentum. Urban forest inventory data analyzed by programs such as the i-Tree ECO inventory method is a good candidate for such an approach. In this research, we tested the feasibility of using spatially referenced data gathered and submitted by non-professional individuals through a web application to augment urban forest inventory data. We examined the use of close range photogrammetry solutions of images taken by consumer-grade cameras to extract quantitative metric information such as crown diameter, tree heights and trunk diameters. Several tests were performed to evaluate the accuracy of the photogrammetric solutions and to examine their use in addition to existing aerial image data to supplement or partially substitute for standard i-Tree ECO field measurements. Digital images of three sample sites were acquired using different consumer-grade cameras. Several photogrammetric solutions were performed using the acquired image sets. Each model was carried out using a relative orientation process followed by baseline model scaling. Several distances obtained through this solution were compared to the corresponding distances obtained through direct measurements in order to assess the quality of the model scaling approach. Measured i-Tree ECO field plot inventory data, online aerial image measurements and photogrammetric observations were compared. The results demonstrate the potential for using aerial image digitizing in addition to ground images to assist in participatory urban forest inventory efforts.

  5. GrinLine identification using digital imaging and Adobe Photoshop.

    PubMed

    Bollinger, Susan A; Brumit, Paula C; Schrader, Bruce A; Senn, David R

    2009-03-01

    The purpose of this study was to outline a method by which an antemortem photograph of a victim can be critically compared with a postmortem photograph in an effort to facilitate the identification process. Ten subjects, between 27 and 55 years old provided historical pictures of themselves exhibiting a broad smile showing anterior teeth to some extent (a grin). These photos were termed "antemortem" for the purpose of the study. A digital camera was used to take a current photo of each subject's grin. These photos represented the "postmortem" images. A single subject's "postmortem" photo set was randomly selected to be the "unknown victim." These combined data of the unknown and the 10 antemortem subjects were digitally stored and, using Adobe Photoshop software, the images were sized and oriented for comparative analysis. The goal was to devise a technique that could facilitate the accurate determination of which "antemortem" subject was the "unknown." The generation of antemortem digital overlays of the teeth visible in a grin and the comparison of those overlays to the images of the postmortem dentition is the foundation of the technique. The comparisons made using the GrinLine Identification Technique may assist medical examiners and coroners in making identifications or exclusions.

  6. Concepts for evaluation of image quality in digital radiology

    NASA Astrophysics Data System (ADS)

    Zscherpel, U.; Ewert, U.; Jechow, M.

    2012-05-01

    Concepts for digital image evaluation are presented for Computed Radiography (CR) and Digital Detector Arrays (DDAs) used for weld inspection. The precise DDA calibration yields an extra ordinary increase of contrast sensitivity up to 10 times in relation to film radiography. Restrictions in spatial resolution caused by pixel size of the DDA are compensated by increased contrast sensitivity. First CR standards were published in 2005 to support the application of phosphor imaging plates in lieu of X-ray film, but they need already a revision based on experiences reported by many users. One of the key concepts is the usage of signal-to-noise (SNR) measurements as equivalent to the optical density of film and film system class. The contrast sensitivity, measured by IQI visibility, depends on three essential parameters: The basic spatial resolution (SRb) of the radiographic image, the achieved signal-to-noise ratio (SNR) and the specific contrast (μeff - effective attenuation coefficient). Knowing these 3 parameters for the given exposure condition, inspected material and monitor viewing condition permits the calculation of the just visible IQI element. Furthermore, this enables the optimization of exposure conditions. The new ISO/FDIS 17636-2 describes the practice for digital radiography with CR and DDAs. It considers the first time compensation principles, derived from the three essential parameters. The consequences are described.

  7. Dynamic Approaches for Facial Recognition Using Digital Image Speckle Correlation

    NASA Astrophysics Data System (ADS)

    Rafailovich-Sokolov, Sara; Guan, E.; Afriat, Isablle; Rafailovich, Miriam; Sokolov, Jonathan; Clark, Richard

    2004-03-01

    Digital image analysis techniques have been extensively used in facial recognition. To date, most static facial characterization techniques, which are usually based on Fourier transform techniques, are sensitive to lighting, shadows, or modification of appearance by makeup, natural aging or surgery. In this study we have demonstrated that it is possible to uniquely identify faces by analyzing the natural motion of facial features with Digital Image Speckle Correlation (DISC). Human skin has a natural pattern produced by the texture of the skin pores, which is easily visible with conventional digital cameras of resolution greater than 4 mega pixels. Hence the application of the DISC method to the analysis of facial motion appears to be very straightforward. Here we demonstrate that the vector diagrams produced by this method for facial images are directly correlated to the underlying muscle structure which is unique for an individual and is not affected by lighting or make-up. Furthermore, we will show that this method can also be used for medical diagnosis in early detection of facial paralysis and other forms of skin disorders.

  8. Computer image processing - The Viking experience. [digital enhancement techniques

    NASA Technical Reports Server (NTRS)

    Green, W. B.

    1977-01-01

    Computer processing of digital imagery from the Viking mission to Mars is discussed, with attention given to subjective enhancement and quantitative processing. Contrast stretching and high-pass filtering techniques of subjective enhancement are described; algorithms developed to determine optimal stretch and filtering parameters are also mentioned. In addition, geometric transformations to rectify the distortion of shapes in the field of view and to alter the apparent viewpoint of the image are considered. Perhaps the most difficult problem in quantitative processing of Viking imagery was the production of accurate color representations of Orbiter and Lander camera images.

  9. Digital image quantification of siderophores on agar plates.

    PubMed

    Andrews, Megan Y; Santelli, Cara M; Duckworth, Owen W

    2016-03-01

    This article presents visual image data and detailed methodology for the use of a new method for quantifying the exudation of siderophores during fungal growth. The data include images showing time series for calibration, fungal exudation, and negative controls, as well as replication accuracy information. In addition, we provide detailed protocols for making CAS assay layer plates, the digital analysis protocol for determining area of color change, and discuss growth media that do and do not work with the layer plate method. The results of these data, their interpretation, and further discussion can be found in Andrews et al., 2016 [1]. PMID:26937467

  10. Evaluation of digital halftones image by vector error diffusion

    NASA Astrophysics Data System (ADS)

    Kouzaki, Masahiro; Itoh, Tetsuya; Kawaguchi, Takayuki; Tsumura, Norimichi; Haneishi, Hideaki; Miyake, Yoichi

    1998-12-01

    The vector error diffusion (VED) method is applied to proudce the digital halftone images by an electrophotographic printer with 600 dpi. Objective image quality of those obtained images is evaluated and analyzed. As a result, in the color reproduction of halftone image by the VED method, it was clear that there are large color difference between target color and printed color typically in the mid-tone colors. We consider it is due to the printer properties including dot-gain. It was also clear that the color noise of the VED method is larger compared with that of the conventional scalar error diffusion method in some patches. It was remarkable that ununiform patterns are generated by the VED method.

  11. Infective endocarditis detection through SPECT/CT images digital processing

    NASA Astrophysics Data System (ADS)

    Moreno, Albino; Valdés, Raquel; Jiménez, Luis; Vallejo, Enrique; Hernández, Salvador; Soto, Gabriel

    2014-03-01

    Infective endocarditis (IE) is a difficult-to-diagnose pathology, since its manifestation in patients is highly variable. In this work, it was proposed a semiautomatic algorithm based on SPECT images digital processing for the detection of IE using a CT images volume as a spatial reference. The heart/lung rate was calculated using the SPECT images information. There were no statistically significant differences between the heart/lung rates values of a group of patients diagnosed with IE (2.62+/-0.47) and a group of healthy or control subjects (2.84+/-0.68). However, it is necessary to increase the study sample of both the individuals diagnosed with IE and the control group subjects, as well as to improve the images quality.

  12. Use of film digitizers to assist radiology image management

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Frost, Meryll M.; Staab, Edward V.

    1996-05-01

    The purpose of this development effort was to evaluate the possibility of using digital technologies to solve image management problems in the Department of Radiology at the University of Florida. The three problem areas investigated were local interpretation of images produced in remote locations, distribution of images to areas outside of radiology, and film handling. In all cases the use of a laser film digitizer interfaced to an existing Picture Archiving and Communication System (PACS) was investigated as a solution to the problem. In each case the volume of studies involved were evaluated to estimate the impact of the solution on the network, archive, and workstations. Communications were stressed in the analysis of the needs for all image transmission. The operational aspects of the solution were examined to determine the needs for training, service, and maintenance. The remote sites requiring local interpretation included were a rural hospital needing coverage for after hours studies, the University of Florida student infirmary, and the emergency room. Distribution of images to the intensive care units was studied to improve image access and patient care. Handling of films originating from remote sites and those requiring urgent reporting were evaluated to improve management functions. The results of our analysis and the decisions that were made based on the analysis are described below. In the cases where systems were installed, a description of the system and its integration into the PACS system is included. For all three problem areas, although we could move images via a digitizer to the archive and a workstation, there was no way to inform the radiologist that a study needed attention. In the case of outside films, the patient did not always have a medical record number that matched one in our Radiology Information Systems (RIS). In order to incorporate all studies for a patient, we needed common locations for orders, reports, and images. RIS orders

  13. A comparison of image interpretation times in full field digital mammography and digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Astley, Susan; Connor, Sophie; Lim, Yit; Tate, Catriona; Entwistle, Helen; Morris, Julie; Whiteside, Sigrid; Sergeant, Jamie; Wilson, Mary; Beetles, Ursula; Boggis, Caroline; Gilbert, Fiona

    2013-03-01

    Digital Breast Tomosynthesis (DBT) provides three-dimensional images of the breast that enable radiologists to discern whether densities are due to overlapping structures or lesions. To aid assessment of the cost-effectiveness of DBT for screening, we have compared the time taken to interpret DBT images and the corresponding two-dimensional Full Field Digital Mammography (FFDM) images. Four Consultant Radiologists experienced in reading FFDM images (4 years 8 months to 8 years) with training in DBT interpretation but more limited experience (137-407 cases in the past 6 months) were timed reading between 24 and 32 two view FFDM and DBT cases. The images were of women recalled from screening for further assessment and women under surveillance because of a family history of breast cancer. FFDM images were read before DBT, according to local practice. The median time for readers to interpret FFDM images was 17.0 seconds, with an interquartile range of 12.3-23.6 seconds. For DBT, the median time was 66.0 seconds, and the interquartile range was 51.1-80.5 seconds. The difference was statistically significant (p<0.001). Reading times were significantly longer in family history clinics (p<0.01). Although it took approximately four times as long to interpret DBT than FFDM images, the cases were more complex than would be expected for routine screening, and with higher mammographic density. The readers were relatively inexperienced in DBT interpretation and may increase their speed over time. The difference in times between clinics may be due to increased throughput at assessment, or decreased density.

  14. Enhancing the Teaching of Digital Processing of Remote Sensing Image Course through Geospatial Web Processing Services

    NASA Astrophysics Data System (ADS)

    di, L.; Deng, M.

    2010-12-01

    Remote sensing (RS) is an essential method to collect data for Earth science research. Huge amount of remote sensing data, most of them in the image form, have been acquired. Almost all geography departments in the world offer courses in digital processing of remote sensing images. Such courses place emphasis on how to digitally process large amount of multi-source images for solving real world problems. However, due to the diversity and complexity of RS images and the shortcomings of current data and processing infrastructure, obstacles for effectively teaching such courses still remain. The major obstacles include 1) difficulties in finding, accessing, integrating and using massive RS images by students and educators, and 2) inadequate processing functions and computing facilities for students to freely explore the massive data. Recent development in geospatial Web processing service systems, which make massive data, computing powers, and processing capabilities to average Internet users anywhere in the world, promises the removal of the obstacles. The GeoBrain system developed by CSISS is an example of such systems. All functions available in GRASS Open Source GIS have been implemented as Web services in GeoBrain. Petabytes of remote sensing images in NASA data centers, the USGS Landsat data archive, and NOAA CLASS are accessible transparently and processable through GeoBrain. The GeoBrain system is operated on a high performance cluster server with large disk storage and fast Internet connection. All GeoBrain capabilities can be accessed by any Internet-connected Web browser. Dozens of universities have used GeoBrain as an ideal platform to support data-intensive remote sensing education. This presentation gives a specific example of using GeoBrain geoprocessing services to enhance the teaching of GGS 588, Digital Remote Sensing taught at the Department of Geography and Geoinformation Science, George Mason University. The course uses the textbook "Introductory

  15. Digital Tomosynthesis for Respiratory Gated Liver Treatment: Clinical Feasibility for Daily Image Guidance

    SciTech Connect

    Wu, Q. Jackie; Meyer, Jeffrey; Fuller, Jessica; Godfrey, Devon; Wang Zhiheng; Zhang Junan; Yin Fangfang

    2011-01-01

    Purpose: Breath-hold (BH) treatment minimizes internal target volumes (ITV) when treating sites prone to motion. Digital tomosynthesis (DTS) imaging has advantages over cone-beam CT (CBCT) for BH imaging: BH-DTS scan can be completed during a single breath-hold, whereas BH-CBCT is usually acquired by parsing the gantry rotation into multiple BH segments. This study evaluates the localization accuracy of DTS for BH treatment of liver tumors. Methods: Both planning CT and on-board DTS/CBCT images were acquired under BH, using the planning CT BH window as reference. Onboard imaging data sets included two independent DTS orientations (coronal and sagittal), and CBCT images. Soft tissue target positioning was measured by each imaging modality and translated into couch shifts. Performance of the two DTS orientations was evaluated by comparing target positioning with the CBCT benchmark, determined by two observers. Results: Image data sets were collected from thirty-eight treatment fractions (14 patients). Mean differences between the two DTS methods and the CBCT method were <1 mm in all directions (except the lateral direction with sagittal-DTS: 1.2 mm); the standard deviation was in the range of 2.1-3.5 mm for all techniques. The Pearson correlation showed good interobserver agreement for the coronal-DTS (0.72-0.78). The interobserver agreement for the sagittal-DTS was good for the in-plane directions (0.70-0.82), but poor in the out-of-plane direction (lateral, 0.26). Conclusions: BH-DTS may be a simpler alternative to BH-CBCT for onboard soft tissue localization of the liver, although the precision of DTS localization appears to be somewhat lower because of the presence of subtle out-of-plane blur.

  16. Regional contrast enhancement and data compression for digital mammographic images

    NASA Astrophysics Data System (ADS)

    Chen, Ji; Flynn, Michael J.; Rebner, Murray

    1993-07-01

    The wide dynamic range of mammograms poses problems for displaying images on an electronic monitor and printing images through a laser printer. In addition, digital mammograms require a large amount of storage and network transmission bandwidth. We applied contrast enhancement and data compression to the segmented images to solve these problems. Using both image intensity and Gaussian filtered images, we separated the original image into three regions: the interior region, the skinline transition region, and the exterior region. In the transition region, unsharp masking process was applied and an adaptive density shift was used to simulate the process of highlighting with a spot light. The exterior region was set to a high density to reduce glare. The interior and skinline regions are the diagnostically informative areas that need to be preserved. Visually lossless coding was done for the interior by the wavelet or subband transform coding method. This was used because there are no block artifacts and a lowpass filtered image is generated by the transform. The exterior region can be represented by a bit-plane image containing only the labeling information or represented by the lower resolution transform coefficients. Therefore, by applying filters of different scales, we can accomplish region segmentation and data compression.

  17. Traffic sign detection in MLS acquired point clouds for geometric and image-based semantic inventory

    NASA Astrophysics Data System (ADS)

    Soilán, Mario; Riveiro, Belén; Martínez-Sánchez, Joaquín; Arias, Pedro

    2016-04-01

    Nowadays, mobile laser scanning has become a valid technology for infrastructure inspection. This technology permits collecting accurate 3D point clouds of urban and road environments and the geometric and semantic analysis of data became an active research topic in the last years. This paper focuses on the detection of vertical traffic signs in 3D point clouds acquired by a LYNX Mobile Mapper system, comprised of laser scanning and RGB cameras. Each traffic sign is automatically detected in the LiDAR point cloud, and its main geometric parameters can be automatically extracted, therefore aiding the inventory process. Furthermore, the 3D position of traffic signs are reprojected on the 2D images, which are spatially and temporally synced with the point cloud. Image analysis allows for recognizing the traffic sign semantics using machine learning approaches. The presented method was tested in road and urban scenarios in Galicia (Spain). The recall results for traffic sign detection are close to 98%, and existing false positives can be easily filtered after point cloud projection. Finally, the lack of a large, publicly available Spanish traffic sign database is pointed out.

  18. Acquiring a dataset of labeled video images showing discomfort in demented elderly.

    PubMed

    Bonroy, Bert; Schiepers, Pieter; Leysens, Greet; Miljkovic, Dragana; Wils, Maartje; De Maesschalck, Lieven; Quanten, Stijn; Triau, Eric; Exadaktylos, Vasileios; Berckmans, Daniel; Vanrumste, Bart

    2009-05-01

    One of the effects of late-stage dementia is the loss of the ability to communicate verbally. Patients become unable to call for help if they feel uncomfortable. The first objective of this article was to record facial expressions of bedridden demented elderly. For this purpose, we developed a video acquisition system (ViAS) that records synchronized video coming from two cameras. Each camera delivers uncompressed color images of 1,024 x 768 pixels, up to 30 frames per second. It is the first time that such a system has been placed in a patient's room. The second objective was to simultaneously label these video recordings with respect to discomfort expressions of the patients. Therefore, we developed a Digital Discomfort Labeling Tool (DDLT). This tool provides an easy-to-use software representation on a tablet PC of validated "paper" discomfort scales. With ViAS and DDLT, 80 different datasets were obtained of about 15 minutes of recordings. Approximately 80% of the recorded datasets delivered the labeled video recordings. The remainder were not usable due to under- or overexposed images and due to the patients being out of view as the system was not properly replaced after care. In one of 6 observed patients, nurses recognized a higher discomfort level that would not have been observed without the DDLT.

  19. Use of Digital Image Technology to 'Clearly' Depict Global Change

    NASA Astrophysics Data System (ADS)

    Molnia, B. F.; Carbo, C. L.

    2014-12-01

    Earth is dynamic and beautiful. Understanding why, when, how, and how fast its surface changes yields information and serves as a source of inspiration. The artistic use of geoscience information can inform the public about what is happening to their planet in a non-confrontational and apolitical way. While individual images may clearly depict a landscape, photographic comparisons are necessary to clearly capture and display annual, decadal, or century-scale impacts of climate and environmental change on Earth's landscapes. After years of effort to artistically communicate geoscience concepts with unenhanced individual photographs or pairs of images, the authors have partnered to maximize this process by using digital image enhancement technology. This is done, not to manipulate the inherent artistic content or information content of the photographs, but to insure that the comparative photo pairs produced are geometrically correct and unambiguous. For comparative photography, information-rich historical photographs are selected from archives, websites, and other sources. After determining the geographic location from which the historical photograph was made, the original site is identified and eventually revisited. There, the historical photos field of view is again photographed, ideally from the original location. From nearly 250 locations revisited, about 175 pairs have been produced. Every effort is made to reoccupy the original historical site. However, vegetation growth, visibility reduction, and co-seismic level change may make this impossible. Also, inherent differences in lens optics, camera construction, and image format may result in differences in the geometry of the new photograph when compared to the old. Upon selection, historical photos are cleaned, contrast stretched, brightness adjusted, and sharpened to maximize site identification and information extraction. To facilitate matching historical and new images, digital files of each are overlain in

  20. Anatomical noise in contrast-enhanced digital mammography. Part II. Dual-energy imaging

    SciTech Connect

    Hill, Melissa L.; Yaffe, Martin J.; Mainprize, James G.; Carton, Ann-Katherine; Saab-Puong, Sylvie; Iordache, Răzvan; Muller, Serge; Jong, Roberta A.; Dromain, Clarisse

    2013-08-15

    Purpose: Dual-energy (DE) contrast-enhanced digital mammography (CEDM) uses an iodinated contrast agent in combination with digital mammography (DM) to evaluate lesions on the basis of tumor angiogenesis. In DE imaging, low-energy (LE) and high-energy (HE) images are acquired after contrast administration and their logarithms are subtracted to cancel the appearance of normal breast tissue. Often there is incomplete signal cancellation in the subtracted images, creating a background “clutter” that can impair lesion detection. This is the second component of a two-part report on anatomical noise in CEDM. In Part I the authors characterized the anatomical noise for single-energy (SE) temporal subtraction CEDM by a power law, with model parameters α and β. In this work the authors quantify the anatomical noise in DE CEDM clinical images and compare this with the noise in SE CEDM. The influence on the anatomical noise of the presence of iodine in the breast, the timing of imaging postcontrast administration, and the x-ray energy used for acquisition are each evaluated.Methods: The power law parameters, α and β, were measured from unprocessed LE and HE images and from DE subtracted images to quantify the anatomical noise. A total of 98 DE CEDM cases acquired in a previous clinical pilot study were assessed. Conventional DM images from 75 of the women were evaluated for comparison with DE CEDM. The influence of the imaging technique on anatomical noise was determined from an analysis of differences between the power law parameters as measured in DM, LE, HE, and DE subtracted images for each subject.Results: In DE CEDM, weighted image subtraction lowers β to about 1.1 from 3.2 and 3.1 in LE and HE unprocessed images, respectively. The presence of iodine has a small but significant effect in LE images, reducing β by about 0.07 compared to DM, with α unchanged. Increasing the x-ray energy, from that typical in DM to a HE beam, significantly decreases α by about 2

  1. Investigating materials for breast nodules simulation by using segmentation and similarity analysis of digital images

    NASA Astrophysics Data System (ADS)

    Siqueira, Paula N.; Marcomini, Karem D.; Sousa, Maria A. Z.; Schiabel, Homero

    2015-03-01

    The task of identifying the malignancy of nodular lesions on mammograms becomes quite complex due to overlapped structures or even to the granular fibrous tissue which can cause confusion in classifying masses shape, leading to unnecessary biopsies. Efforts to develop methods for automatic masses detection in CADe (Computer Aided Detection) schemes have been made with the aim of assisting radiologists and working as a second opinion. The validation of these methods may be accomplished for instance by using databases with clinical images or acquired through breast phantoms. With this aim, some types of materials were tested in order to produce radiographic phantom images which could characterize a good enough approach to the typical mammograms corresponding to actual breast nodules. Therefore different nodules patterns were physically produced and used on a previous developed breast phantom. Their characteristics were tested according to the digital images obtained from phantom exposures at a LORAD M-IV mammography unit. Two analysis were realized the first one by the segmentation of regions of interest containing the simulated nodules by an automated segmentation technique as well as by an experienced radiologist who has delineated the contour of each nodule by means of a graphic display digitizer. Both results were compared by using evaluation metrics. The second one used measure of quality Structural Similarity (SSIM) to generate quantitative data related to the texture produced by each material. Although all the tested materials proved to be suitable for the study, the PVC film yielded the best results.

  2. High-speed digital phonoscopy images analyzed by Nyquist plots

    NASA Astrophysics Data System (ADS)

    Yan, Yuling

    2012-02-01

    Vocal-fold vibration is a key dynamic event in voice production, and the vibratory characteristics of the vocal fold correlate closely with voice quality and health condition. Laryngeal imaging provides direct means to observe the vocal fold vibration; in the past, however, available modalities were either too slow or impractical to resolve the actual vocal fold vibrations. This limitation has now been overcome by high-speed digital imaging (HSDI) (or high-speed digital phonoscopy), which records images of the vibrating vocal folds at a rate of 2000 frames per second or higher- fast enough to resolve a specific, sustained phonatory vocal fold vibration. The subsequent image-based functional analysis of voice is essential to better understanding the mechanism underlying voice production, as well as assisting the clinical diagnosis of voice disorders. Our primary objective is to develop a comprehensive analytical platform for voice analysis using the HSDI recordings. So far, we have developed various analytical approaches for the HSDI-based voice analyses. These include Nyquist plots and associated analysese that are used along with FFT and Spectrogram in the analysis of the HSDI data representing normal voice and specific voice pathologies.

  3. Development Of A Physician-Friendly Digital Image Display Console

    NASA Astrophysics Data System (ADS)

    van der Voorde, F.; Arenson, R.; Kundel, H.; Miller, W.; Epstein, D.; Gefter, W.; Seshadri, S.; Brikman, I.; Khalsa, S.

    1986-06-01

    A high speed fiber optic network for the transmission of digital images has been under development for the last three years at our Hospital. This network utilizes a ring architecture with token passing contention handling. Radiographs are digitized with a high resolution camera. Images can be viewed at either high or low resolution. The software for this four node Medical Image Management System (MIMS) is now complete and is undergoing trial runs. Clinical tests begin on March 1, 1986. This paper will focus on the philosophy, evolution and the present state of the interfaces that exist between the system and the physician. Care has been taken to develop an interface that is fast, powerful and error-free. Though simple to use, it presents the physician with a number of powerful options to manipulate the image to facilitate effective interpretation. An effort has been made to incorporate those functions that are useful to the physician. We tried to avoid cluttering the user menu with an array of less-used options.

  4. The Challenge of Digital Imaging Technologies: A Practical View of the Future.

    ERIC Educational Resources Information Center

    Hamber, Anthony

    1994-01-01

    Discusses digital imaging technologies. Topics include information technology; reprographics; scientific imaging processing; political considerations of telecommunications and the information superhighway; digital cameras; slide and transparency scanners; desktop prepress processing; digital proofing devices; direct-to-plate and direct-to-press…

  5. From Horse-Drawn Wagon to Hot Rod: The University of California's Digital Image Service Experience

    ERIC Educational Resources Information Center

    Burns, Maureen A.

    2006-01-01

    This article proposes that a viable approach archivists might consider to meet increasing demands for access to digital images with functional presentation tools is to develop a reciprocal partnership with a digital library. The University of California's experience with the federation of licensed and UC-owned digital image collections is…

  6. High Res at High Speed: Automated Delivery of High-Resolution Images from Digital Library Collections

    ERIC Educational Resources Information Center

    Westbrook, R. Niccole; Watkins, Sean

    2012-01-01

    As primary source materials in the library are digitized and made available online, the focus of related library services is shifting to include new and innovative methods of digital delivery via social media, digital storytelling, and community-based and consortial image repositories. Most images on the Web are not of sufficient quality for most…

  7. Preoperative digital mammography imaging in conservative mastectomy and immediate reconstruction

    PubMed Central

    Angrigiani, Claudio; Hammond, Dennis; Nava, Maurizio; Gonzalez, Eduardo; Rostagno, Roman; Gercovich, Gustavo

    2016-01-01

    Background Digital mammography clearly distinguishes gland tissue density from the overlying non-glandular breast tissue coverage, which corresponds to the existing tissue between the skin and the Cooper’s ligaments surrounding the gland (i.e., dermis and subcutaneous fat). Preoperative digital imaging can determine the thickness of this breast tissue coverage, thus facilitating planning of the most adequate surgical techniques and reconstructive procedures for each case. Methods This study aimed to describe the results of a retrospective study of 352 digital mammograms in 176 patients with different breast volumes who underwent preoperative conservative mastectomies. The breast tissue coverage thickness and its relationship with the breast volume were evaluated. Results The breast tissue coverage thickness ranged from 0.233 to 4.423 cm, with a mean value of 1.952 cm. A comparison of tissue coverage and breast volume revealed a non-direct relationship between these factors. Conclusions Preoperative planning should not depend only on breast volume. Flap evaluations based on preoperative imaging measurements might be helpful when planning a conservative mastectomy. Accordingly, we propose a breast tissue coverage classification (BTCC). PMID:26855903

  8. Dynamic magnetic resonance imaging of endoscopic third ventriculostomy patency with differently acquired fast imaging with steady-state precession sequences.

    PubMed

    Lucic, Milos A; Koprivsek, Katarina; Kozic, Dusko; Spero, Martina; Spirovski, Milena; Lucic, Silvija

    2014-08-16

    The aim of the study was to determine the possibilities of two differently acquired two-dimensional fast imaging with steady-state precession (FISP 2D) magnetic resonance sequences in estimation of the third ventricle floor fenestration patency after endoscopic third ventriculostomy (ETV) in the subjects with aqueductal stenosis/obstruction.Fifty eight subjects (37 males, 21 females, mean age 27 years) with previously successfully performed ETV underwent brain MRI on 1.5T MR imager 3-6 months after the procedure. Two different FISP 2D sequences (one included in the standard vendor provided software package, and the other, experimentally developed by our team) were performed respectively at two fixed slice positions: midsagittal and perpendicular to the ETV fenestration, and displayed in a closed-loop cinematographic format in order to estimate the patency. The ventricular volume reduction has been observed as well.Cerebrospinal fluid (CSF) flow through the ETV fenestration was observed in midsagittal plane with both FISP 2D sequences in 93.11% subjects, while in 6.89% subjects the dynamic CSF flow MRI was inconclusive. In the perpendicular plane CSF flow through the ETV fenestration was visible only by use of experimentally developed FISP 2D (TR30/FA70) sequence. Postoperative volume reduction of lateral and third ventricle was detected in 67.24% subjects.Though both FISP 2D sequences acquired in midsagittal plane may be used to estimate the effects of performed ETV, due to achieved higher CSF pulsatile flow sensitivity, only the use of FISP 2D (TR30/FA70) sequence enables the estimation of the treatment effect in perpendicular plane in the absence of phase-contrast sequences. 

  9. Autocorrelation and regularization in digital images. I - Basic theory

    NASA Technical Reports Server (NTRS)

    Jupp, David L. B.; Strahler, Alan H.; Woodcock, Curtis E.

    1988-01-01

    Spatial structure occurs in remotely sensed images when the imaged scenes contain discrete objects that are identifiable in that their spectral properties are more homogeneous within than between them and other scene elements. The spatial structure introduced is manifest in statistical measures such as the autocovariance function and variogram associated with the scene, and it is possible to formulate these measures explicitly for scenes composed of simple objects of regular shapes. Digital images result from sensing scenes by an instrument with an associated point spread function (PSF). Since there is averaging over the PSF, the effect, termed regularization, induced in the image data by the instrument will influence the observable autocovariance and variogram functions of the image data. It is shown how the autocovariance or variogram of an image is a composition of the underlying scene covariance convolved with an overlap function, which is itself a convolution of the PSF. The functional form of this relationship provides an analytic basis for scene inference and eventual inversion of scene model parameters from image data.

  10. The wavelet/scalar quantization compression standard for digital fingerprint images

    SciTech Connect

    Bradley, J.N.; Brislawn, C.M.

    1994-04-01

    A new digital image compression standard has been adopted by the US Federal Bureau of Investigation for use on digitized gray-scale fingerprint images. The algorithm is based on adaptive uniform scalar quantization of a discrete wavelet transform image decomposition and is referred to as the wavelet/scalar quantization standard. The standard produces archival quality images at compression ratios of around 20:1 and will allow the FBI to replace their current database of paper fingerprint cards with digital imagery.

  11. Characterization of LANDSAT-4 MSS and TM digital image data

    NASA Technical Reports Server (NTRS)

    Malila, W. A.; Metzler, M. D.; Rice, D. P.; Crist, E. P.

    1985-01-01

    The launch of LANDSAT-4 in July 1982 represents a continuation in the remote sensing of earth resources. The 80-m spatial resolution provided by the Multispectral Scanner (MSS) on board the satellite is fine enough to resolve many natural features and land-use details in both rural and urban settings. The second sensor of the spacecraft, the Thematic Mapper (TM), introduce a new era of sensing with refined spatial resolution (30 m) and expanded spectral coverage (7 bands). This paper describes results from engineering studies of the characteristics of digital image data from the two LANDSAT-4 sensors are described. These studies form a part of the LANDSAT-4 Image Data Quality Analysis program (LIDQA). The image data were generally found to be of high quality and the TM provided several improvements over the MSS, in its spatial and spectral characteristics.

  12. Characterization of Landsat-4 MSS and TM digital image data

    NASA Technical Reports Server (NTRS)

    Malila, W. A.; Metzler, M. D.; Rice, D. P.; Crist, E. P.

    1984-01-01

    The launch of Landsat-4 in July 1982 represents a continuation in the remote sensing of earth resources. The 80-m spatial resolution provided by the Multispectral Scanner (MSS) on board the satellite is fine enough to resolve many natural features and land-use details in both rural and urban settings. The second sensor of the spacecraft, the Thematic Mapper (TM), introduces a new era of sensing with refined spatial resolution (30 m) and expanded spectral coverage (7 bands). This paper describes results from engineering studies of the characteristics of digital image data from the two Landsat-4 sensors. These studies form a part of the Landsat-4 Image Data Quality Analysis program (LIDQA). The image data were generally found to be of high quality and the TM provided several improvements over the MSS, in its spatial and spectral characteristics.

  13. [Digital library for archiving files of radiology and medical imaging].

    PubMed

    Duvauferrier, R; Rambeau, M; Moulène, F

    1993-01-01

    The Conseil des Enseignants de Radiologie de France in collaboration with the Ilab-TSI company and Schering laboratories has developed a computer programme allowing the storage and consultation of radiological teaching files. This programme, developed on Macintosh from standard Hypercard and Quicktime applications, allows, in consultation mode, the multicriteria search and visualisation of selected radiological files. In the author mode, new files can be included after digitalizing the author's own images or after obtaining images from another image library. This programme, which allows juxtaposition of digitalised radiological files, is designed to be extremely open and can be easily combined with other computer-assisted teaching or computer-assisted presentation applications. PMID:7509583

  14. Processing techniques for digital sonar images from GLORIA.

    USGS Publications Warehouse

    Chavez, P.S.

    1986-01-01

    Image processing techniques have been developed to handle data from one of the newest members of the remote sensing family of digital imaging systems. This paper discusses software to process data collected by the GLORIA (Geological Long Range Inclined Asdic) sonar imaging system, designed and built by the Institute of Oceanographic Sciences (IOS) in England, to correct for both geometric and radiometric distortions that exist in the original 'raw' data. Preprocessing algorithms that are GLORIA-specific include corrections for slant-range geometry, water column offset, aspect ratio distortion, changes in the ship's velocity, speckle noise, and shading problems caused by the power drop-off which occurs as a function of range.-from Author

  15. Characterisation of an oxy-coal flame through digital imaging

    SciTech Connect

    Smart, John; Riley, Gerry; Lu, Gang; Yan, Yong

    2010-06-15

    This paper presents investigations into the impact of oxy-fuel combustion on flame characteristics through the application of digital imaging and image processing techniques. The characteristic parameters of the flame are derived from flame images that are captured using a vision-based flame monitoring system. Experiments were carried out on a 0.5 MW{sub th} coal combustion test facility. Different flue gas recycle ratios and furnace oxygen levels were created for two different coals. The characteristics of the flame and the correlation between the measured flame parameters and corresponding combustion conditions are described and discussed. The results show that the flame temperature decreases with the recycle ratio for both test coals, suggesting that the flame temperature is effectively controlled by the flue gas recycle ratio. The presence of high levels of CO{sub 2} at high flue gas recycle ratios may result in delayed combustion and thus has a detrimental effect on the flame stability. (author)

  16. Automatic Microaneurysm Detection and Characterization Through Digital Color Fundus Images

    SciTech Connect

    Martins, Charles; Veras, Rodrigo; Ramalho, Geraldo; Medeiros, Fatima; Ushizima, Daniela

    2008-08-29

    Ocular fundus images can provide information about retinal, ophthalmic, and even systemic diseases such as diabetes. Microaneurysms (MAs) are the earliest sign of Diabetic Retinopathy, a frequently observed complication in both type 1 and type 2 diabetes. Robust detection of MAs in digital color fundus images is critical in the development of automated screening systems for this kind of disease. Automatic grading of these images is being considered by health boards so that the human grading task is reduced. In this paper we describe segmentation and the feature extraction methods for candidate MAs detection.We show that the candidate MAs detected with the methodology have been successfully classified by a MLP neural network (correct classification of 84percent).

  17. Quantifying biodiversity using digital cameras and automated image analysis.

    NASA Astrophysics Data System (ADS)

    Roadknight, C. M.; Rose, R. J.; Barber, M. L.; Price, M. C.; Marshall, I. W.

    2009-04-01

    Monitoring the effects on biodiversity of extensive grazing in complex semi-natural habitats is labour intensive. There are also concerns about the standardization of semi-quantitative data collection. We have chosen to focus initially on automating the most time consuming aspect - the image analysis. The advent of cheaper and more sophisticated digital camera technology has lead to a sudden increase in the number of habitat monitoring images and information that is being collected. We report on the use of automated trail cameras (designed for the game hunting market) to continuously capture images of grazer activity in a variety of habitats at Moor House National Nature Reserve, which is situated in the North of England at an average altitude of over 600m. Rainfall is high, and in most areas the soil consists of deep peat (1m to 3m), populated by a mix of heather, mosses and sedges. The cameras have been continuously in operation over a 6 month period, daylight images are in full colour and night images (IR flash) are black and white. We have developed artificial intelligence based methods to assist in the analysis of the large number of images collected, generating alert states for new or unusual image conditions. This paper describes the data collection techniques, outlines the quantitative and qualitative data collected and proposes online and offline systems that can reduce the manpower overheads and increase focus on important subsets in the collected data. By converting digital image data into statistical composite data it can be handled in a similar way to other biodiversity statistics thus improving the scalability of monitoring experiments. Unsupervised feature detection methods and supervised neural methods were tested and offered solutions to simplifying the process. Accurate (85 to 95%) categorization of faunal content can be obtained, requiring human intervention for only those images containing rare animals or unusual (undecidable) conditions, and

  18. Digital image processing as a tool for pavement distress evaluation

    NASA Astrophysics Data System (ADS)

    Georgopoulos, A.; Loizos, A.; Flouda, A.

    The information obtained through accurate condition assessment of pavement surface distress data is needed as an essential input to any decision making process concerning pavement management policy. At the same time technological advances in automated inspection systems provide the opportunity to automate the collection and evaluation of the pavement surface condition. In this paper a method developed jointly by the Laboratories of Highway Engineering and Photogrammetry of the National Technical University of Athens is described and proposed. The method involves digital image processing techniques to provide suitable digital imagery as input to specialised software developed especially for this project. This software determines objectively and fully automatically the type, the extent and the severity of surface crackings for flexible road pavements. The proposed method presenten substantial agreement, when compared with systematic visual ratings of existing pavement crackings carried out according to the internationally accepted requirements for airfield and road pavement of the Federal Aviation Administration (FAA).

  19. Precision Improvement of Photogrammetry by Digital Image Correlation

    NASA Astrophysics Data System (ADS)

    Shih, Ming-Hsiang; Sung, Wen-Pei; Tung, Shih-Heng; Hsiao, Hanwei

    2016-04-01

    The combination of aerial triangulation technology and unmanned aerial vehicle greatly reduces the cost and application threshold of the digital surface model technique. Based on the report in the literatures, the measurement error in the x-y coordinate and in the elevation lies between 8cm~15cm and 10cm~20cm respectively. The measurement accuracy for the geological structure survey already has sufficient value, but for the slope and structures in terms of deformation monitoring is inadequate. The main factors affecting the accuracy of the aerial triangulation are image quality, measurement accuracy of control point and image matching accuracy. In terms of image matching, the commonly used techniques are Harris Corner Detection and Scale Invariant Feature Transform (SIFT). Their pairing error is in scale of pixels, usually lies between 1 to 2 pixels. This study suggests that the error on the pairing is the main factor causing the aerial triangulation errors. Therefore, this study proposes the application of Digital Image Correlation (DIC) method instead of the pairing method mentioned above. DIC method can provide a pairing accuracy of less than 0.01 pixel, indeed can greatly enhance the accuracy of the aerial triangulation, to have sub-centimeter level accuracy. In this study, the effects of image pairing error on the measurement error of the 3-dimensional coordinate of the ground points are explored by numerical simulation method. It was confirmed that when the image matching error is reduced to 0.01 pixels, the ground three-dimensional coordinate measurement error can be controlled in mm level. A combination of DIC technique and the traditional aerial triangulation provides the potential of application on the deformation monitoring of slope and structures, and achieve an early warning of natural disaster.

  20. Development of Global 30m Resolution Water Body Map with Permanent/Temporal Water Body Separation Using Satellite Acquired Images of Landsat GLS Datasets

    NASA Astrophysics Data System (ADS)

    Ikeshima, D.; Yamazaki, D.; Yoshikawa, S.; Kanae, S.

    2015-12-01

    The specification of worldwide water body distribution is important for discovering hydrological cycle. Global 3-second Water Body Map (G3WBM) is a global scale map, which indicates the distribution of water body in 90m resolutions (http://hydro.iis.u-tokyo.ac.jp/~yamadai/G3WBM/index.html). This dataset was mainly built to identify the width of river channels, which is one of major uncertainties of continental-scale river hydrodynamics models. To survey the true width of the river channel, this water body map distinguish Permanent Water Body from Temporary Water Body, which means separating river channel and flood plain. However, rivers with narrower width, which is a major case in usual river, could not be observed in this map. To overcome this problem, updating the algorithm of G3WBM and enhancing the resolutions to 30m is the goal of this research. Although this 30m-resolution water body map uses similar algorithm as G3WBM, there are many technical issues attributed to relatively high resolutions. Those are such as lack of same high-resolution digital elevation map, or contamination problem of sub-pixel scale object on satellite acquired image, or invisibility of well-vegetated water body such as swamp. To manage those issues, this research used more than 30,000 satellite images of Landsat Global Land Survey (GLS), and lately distributed topography data of Shuttle Rader Topography Mission (SRTM) 1 arc-second (30m) digital elevation map. Also the effect of aerosol, which would scatter the sun reflectance and disturb the acquired result image, was considered. Due to these revises, the global water body distribution was established in more precise resolution.

  1. Digital-signal-processor-based dynamic imaging system for optical tomography.

    PubMed

    Lasker, Joseph M; Masciotti, James M; Schoenecker, Matthew; Schmitz, Christoph H; Hielscher, Andreas H

    2007-08-01

    In this article, we introduce a dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data acquisition and filtering techniques. At the core of this continuous wave instrument is a digital signal processor (DSP) that collects, collates, processes, and filters the digitized data set. The processor is also responsible for managing system timing and the imaging routines which can acquire real-time data at rates as high as 150 Hz. Many of the synchronously timed processes are controlled by a complex programmable logic device that is also used in conjunction with the DSP to orchestrate data flow. The operation of the system is implemented through a comprehensive graphical user interface designed with LABVIEW software which integrates automated calibration, data acquisition, data organization, and signal postprocessing. Performance analysis demonstrates very low system noise (approximately 1 pW rms noise equivalent power), excellent signal precision (<0.04%-0.2%) and long term system stability (<1% over 40 min). A large dynamic range (approximately 190 dB) accommodates a wide scope of measurement geometries and tissue types. First experiments on tissue phantoms show that dynamic behavior is accurately captured and spatial location can be correctly tracked using this system.

  2. High-performance VGA-resolution digital color CMOS imager

    NASA Astrophysics Data System (ADS)

    Agwani, Suhail; Domer, Steve; Rubacha, Ray; Stanley, Scott

    1999-04-01

    This paper discusses the performance of a new VGA resolution color CMOS imager developed by Motorola on a 0.5micrometers /3.3V CMOS process. This fully integrated, high performance imager has on chip timing, control, and analog signal processing chain for digital imaging applications. The picture elements are based on 7.8micrometers active CMOS pixels that use pinned photodiodes for higher quantum efficiency and low noise performance. The image processing engine includes a bank of programmable gain amplifiers, line rate clamping for dark offset removal, real time auto white balancing, per column gain and offset calibration, and a 10 bit pipelined RSD analog to digital converter with a programmable input range. Post ADC signal processing includes features such as bad pixel replacement based on user defined thresholds levels, 10 to 8 bit companding and 5 tap FIR filtering. The sensor can be programmed via a standard I2C interface that runs on 3.3V clocks. Programmable features include variable frame rates using a constant frequency master clock, electronic exposure control, continuous or single frame capture, progressive or interlace scanning modes. Each pixel is individually addressable allowing region of interest imaging and image subsampling. The sensor operates with master clock frequencies of up to 13.5MHz resulting in 30FPS. A total programmable gain of 27dB is available. The sensor power dissipation is 400mW at full speed of operation. The low noise design yields a measured 'system on a chip' dynamic range of 50dB thus giving over 8 true bits of resolution. Extremely high conversion gain result in an excellent peak sensitivity of 22V/(mu) J/cm2 or 3.3V/lux-sec. This monolithic image capture and processing engine represent a compete imaging solution making it a true 'camera on a chip'. Yet in its operation it remains extremely easy to use requiring only one clock and a 3.3V power supply. Given the available features and performance levels, this sensor will be

  3. Measurement of ocular torsion using digital fundus image.

    PubMed

    Seo, J; Kim, K; Kim, J; Park, K; Chung, H

    2004-01-01

    Computer-based objective measurement of the ocular cyclotorsion using digital fundus photograph was developed. Color digital fundus photographs acquired with the field angle of 60 degrees , 1520 x 1080 in resolution were analyzed. Optic disc and macula were segmented by the program developed on MATLAB, which executed the serial analysis of the Otsu threshold, labeling, Canny edge. The angle between the horizontal line that bisects the optic disc and the line connecting the center of optic disc and macula was measured and compared with the torsion determined by the specialist. Optic disc and macula were segmented and the mean of the calculated angle was 3.02+/-1.24 degrees . The mean of the torsion determined by the specialist was 3.13+/-1.98 degrees and there was no difference between the two. The measurement of the cyclotorsion using computer program showed good coincidence with that of the specialist and it can be a good candidate as a tool helping precise diagnosis and the objective evaluation of the disease for the physicians.

  4. Optimisation techniques for digital image reconstruction from their projections

    NASA Astrophysics Data System (ADS)

    Durrani, T. S.; Goutis, C. E.

    1980-09-01

    A method is proposed for the digital reconstruction of images from their projections based on optimizing specified performance criteria. The reconstruction problem is embedded into the framework of constrained optimization and its solution is shown to lead to a relationship between the image and the one-dimensional Lagrange functions associated with each cost criterion. Two types of geometries (the parallel-beam and fan-beam systems) are considered for the acquisition of projection data and the constrained-optimization problem is solved for both. The ensuing algorithms allow the reconstruction of multidimensional objects from one-dimensional functions only. For digital data a fast reconstruction algorithm is proposed which exploits the symmetries inherent in both a circular domain of image reconstruction and in projections obtained at equispaced angles. Computational complexity is significantly reduced by the use of fast-Fourier-transform techniques, as the underlying relationship between the available projection data and the associated Lagrange multipliers is shown to possess a block circulant matrix structure.

  5. Modulated digital images for biometric and other security applications

    NASA Astrophysics Data System (ADS)

    McCarthy, Lawry D.; Lee, Robert A.; Swiegers, Gerhard F.

    2004-06-01

    There are, in general, two ways for an observer to deal with light that is incorrect in some way (e.g. which is partially out of focus). One approach is to correct the error (e.g. by using a lens to selectively bend the light). Another approach employs selective masking to block those portions of the light which are unwanted (e.g. out of focus). The principle of selective masking is used in a number of important industries. However it has not found widespread application in the field of optical security devices. This work describes the selective masking, or modulation, of digital images as a means of creating documents and transparent media containing overt or covert biometric and other images. In particular, we show how animation effects, flash-illumination features, color-shifting patches, information concealment devices, and biometric portraiture in various settings can be incorporated in transparent media like plastic packaging materials, credit cards, and plastic banknotes. We also demonstrate the application of modulated digital images to the preparation of optically variable diffractive foils which are readily customized to display biometric portraits and information. Selective masking is shown to be an important means of creating a diverse range of effects useful in authentication. Such effects can be readily and inexpensively produced without the need, for example, to fabricate lenses on materials which may not be conducive in this respect.

  6. Design of adaptive steganographic schemes for digital images

    NASA Astrophysics Data System (ADS)

    Filler, Tomás; Fridrich, Jessica

    2011-02-01

    Most steganographic schemes for real digital media embed messages by minimizing a suitably defined distortion function. In practice, this is often realized by syndrome codes which offer near-optimal rate-distortion performance. However, the distortion functions are designed heuristically and the resulting steganographic algorithms are thus suboptimal. In this paper, we present a practical framework for optimizing the parameters of additive distortion functions to minimize statistical detectability. We apply the framework to digital images in both spatial and DCT domain by first defining a rich parametric model which assigns a cost of making a change at every cover element based on its neighborhood. Then, we present a practical method for optimizing the parameters with respect to a chosen detection metric and feature space. We show that the size of the margin between support vectors in soft-margin SVMs leads to a fast detection metric and that methods minimizing the margin tend to be more secure w.r.t. blind steganalysis. The parameters obtained by the Nelder-Mead simplex-reflection algorithm for spatial and DCT-domain images are presented and the new embedding methods are tested by blind steganalyzers utilizing various feature sets. Experimental results show that as few as 80 images are sufficient for obtaining good candidates for parameters of the cost model, which allows us to speed up the parameter search.

  7. Morphological Variability and Grain Size From Digital Images

    NASA Astrophysics Data System (ADS)

    Gallagher, E. L.; Macmahan, J.; Russell, P.; Masselink, G.

    2006-12-01

    In the past, hydrodynamic and morphologic coastal modelers have assumed that the sand layer on the beach is thick, well-sorted (uniform in grain size) and relatively smooth. Many recent studies contradict this assumption and suggest that sediments on a beach are not homogeneous and that variations in sediment size and supply are important in sediment transport and morphodynamics at all scales. Unfortunately, traditional techniques for measuring grain size are difficult, tedious and time consuming. Therefore, in spite of the evidence pointing to the importance of grain size and its variability in sediment transport and morphodynamics, most of the studies are based on relatively few field samples. In May 2006, a new digital imaging system for measuring grain size quickly and efficiently was used during a field experiment that took place at Truc Vert on the west coast of France. The field site is a high-energy, macro-tidal beach characterized by beach cusps, crescentic bars and a rip channel system. The digital imaging system was used to conduct daily surveys of sand size, alongside simultaneous surveys of beach morphology and traditional sand sampling. Preliminary results are promising and suggest that the imaging system is ideal for sampling large areas for detailed spatial grain size information. The data will be examined for morphological and sedimentological variability associated with the complex morphology at Truc Vert.

  8. Role of color and spatial resolution in digital imaging colposcopy

    NASA Astrophysics Data System (ADS)

    Craine, Eric R.; Engel, John R.; Craine, Brian L.

    1990-07-01

    We have developed a practical digital imaging colposcope for use in research on early detection of cancerous and pre-cancerous tissue in the cervix. Several copies of the system have now been used in a variety of clinical and research environments. Two issues of considerable interest which emerged early in our work involved the roles of color and spatial resolution as they applied to digital imaging colposcopy. In each instance these qualities potentially have a significant impact on the diagnostic efficacy of the system. In order to evaluate the role of these parameters we devised and conducted a receiver operating characteristic (ROC) evaluation of the system. It is apparent from these tests that a spatial resolution of 512 x 480 pixel with 7 or 8 bits of contrast is adequate for the task. The more interesting result arises from the study of the use of color in these examinations; it appears that in general, contrary to the widely held perception of the physicians involved, color apparently provides the clinician with little or no diagnostic information. Indeed, in some instances, access to color seemed to confuse the physician and resulted in an elevated rate of false positives. Results of the ROC tests are presented in this paper along with their implications for further development of this imaging modality.

  9. Single-image hard copy display of musculoskeletal digital radiographs

    NASA Astrophysics Data System (ADS)

    Legendre, Kevin; Steller Artz, Dorothy E.; Freedman, Matthew T.; Mun, Seong K.

    1995-04-01

    Screen film radiography often fails to optimally display all regions of anatomy on muskuloskeletal exams due to the wide latitude of tissue densities present. Various techniques of image enhancement have been applied to such exams using computerized radiography but with limited success in improving visualization of structures whose final optical density lies at the extremes of the interpretable range of the film. An existing algorithm for compressing optical density extremes known as dynamic range compression has been used to increase the radiodensity of the retrocardiac region of the chest or to decrease the radiodensity of the edge of the breast in digital mammography. In the skeletal system, there are regions where a single image may contain both areas of decreased exposure that result in light images and areas of higher exposure that result in dark regions of the image. Faced with this problem, the senior author asked Fuji to formulate a modification of the DRC process that incorporates a combination of the curves used for chest and breast images. The newly designed algorithm can thus simultaneously lower the optical density of dark regions of the image and increase the optical density of the less exposed regions. The results of this modification of the DRC algorithm are presented in this paper.

  10. Camera system resolution and its influence on digital image correlation

    DOE PAGES

    Reu, Phillip L.; Sweatt, William; Miller, Timothy; Fleming, Darryn

    2014-09-21

    Digital image correlation (DIC) uses images from a camera and lens system to make quantitative measurements of the shape, displacement, and strain of test objects. This increasingly popular method has had little research on the influence of the imaging system resolution on the DIC results. This paper investigates the entire imaging system and studies how both the camera and lens resolution influence the DIC results as a function of the system Modulation Transfer Function (MTF). It will show that when making spatial resolution decisions (including speckle size) the resolution limiting component should be considered. A consequence of the loss ofmore » spatial resolution is that the DIC uncertainties will be increased. This is demonstrated using both synthetic and experimental images with varying resolution. The loss of image resolution and DIC accuracy can be compensated for by increasing the subset size, or better, by increasing the speckle size. The speckle-size and spatial resolution are now a function of the lens resolution rather than the more typical assumption of the pixel size. The study will demonstrate the tradeoffs associated with limited lens resolution.« less

  11. Digital Images Are Data: And Should Be Treated as Such

    PubMed Central

    Cromey, Douglas W.

    2014-01-01

    The scientific community has become very concerned about inappropriate image manipulation. In journals that check figures after acceptance, 20–25% of the papers contained at least one figure that did not comply with the journal’s instructions to authors. The scientific press continues to report a small, but steady stream of cases of fraudulent image manipulation. Inappropriate image manipulation taints the scientific record, damages trust within science, and degrades science’s reputation with the general public. Scientists can learn from historians and photojournalists, who have provided a number of examples of attempts to alter or misrepresent the historical record. Scientists must remember that digital images are numerically sampled data that represent the state of a specific sample when examined with a specific instrument. These data should be carefully managed. Changes made to the original data need to be tracked like the protocols used for other experimental procedures. To avoid pitfalls, unexpected artifacts, and unintentional misrepresentation of the image data, a number of image processing guidelines are offered. PMID:23026995

  12. Camera system resolution and its influence on digital image correlation

    SciTech Connect

    Reu, Phillip L.; Sweatt, William; Miller, Timothy; Fleming, Darryn

    2014-09-21

    Digital image correlation (DIC) uses images from a camera and lens system to make quantitative measurements of the shape, displacement, and strain of test objects. This increasingly popular method has had little research on the influence of the imaging system resolution on the DIC results. This paper investigates the entire imaging system and studies how both the camera and lens resolution influence the DIC results as a function of the system Modulation Transfer Function (MTF). It will show that when making spatial resolution decisions (including speckle size) the resolution limiting component should be considered. A consequence of the loss of spatial resolution is that the DIC uncertainties will be increased. This is demonstrated using both synthetic and experimental images with varying resolution. The loss of image resolution and DIC accuracy can be compensated for by increasing the subset size, or better, by increasing the speckle size. The speckle-size and spatial resolution are now a function of the lens resolution rather than the more typical assumption of the pixel size. The study will demonstrate the tradeoffs associated with limited lens resolution.

  13. Digital image modification detection using color information and its histograms.

    PubMed

    Zhou, Haoyu; Shen, Yue; Zhu, Xinghui; Liu, Bo; Fu, Zigang; Fan, Na

    2016-09-01

    The rapid development of many open source and commercial image editing software makes the authenticity of the digital images questionable. Copy-move forgery is one of the most widely used tampering techniques to create desirable objects or conceal undesirable objects in a scene. Existing techniques reported in the literature to detect such tampering aim to improve the robustness of these methods against the use of JPEG compression, blurring, noise, or other types of post processing operations. These post processing operations are frequently used with the intention to conceal tampering and reduce tampering clues. A robust method based on the color moments and other five image descriptors is proposed in this paper. The method divides the image into fixed size overlapping blocks. Clustering operation divides entire search space into smaller pieces with similar color distribution. Blocks from the tampered regions will reside within the same cluster since both copied and moved regions have similar color distributions. Five image descriptors are used to extract block features, which makes the method more robust to post processing operations. An ensemble of deep compositional pattern-producing neural networks are trained with these extracted features. Similarity among feature vectors in clusters indicates possible forged regions. Experimental results show that the proposed method can detect copy-move forgery even if an image was distorted by gamma correction, addictive white Gaussian noise, JPEG compression, or blurring. PMID:27391780

  14. Clinical Application of High-Resolution Computed Tomographic Imaging Features of Community-Acquired Pneumonia

    PubMed Central

    Nie, Yunqiang; Li, Cuiyun; Zhang, Jingling; Wang, Hui; Han, Ping; Lv, Xin; Xu, Xinyi; Guo, Miao

    2016-01-01

    Background This article discusses the value of high-resolution computed tomography (HRCT) in the diagnosis and treatment of pulmonary infections. Lung infection caused by pathogens is an important cause of death. Traditional methods to treat lung infection involved empirical antibiotic therapy. Thin-slice CT scanning is widely used in the clinical setting, and HRCT scan can very clearly show alveolar and bronchiolar involvement of infection. Material/Methods In total, 178 patients with community-acquired pneumonia (CAP) were enrolled. All the patients underwent CT scan, qualified sputum, and blood samples for culture or immunological biochemical tests. CT imaging features, pathogenic bacteria, and treatment results were used for statistical analysis. Results In 77 patients with lobar consolidation, the rate of detection was 43.26% (77/178), and in 101 patients with lobular pneumonia it was 56.74% (101/178). In 51 patients, pathogenic bacteria were detected (28.65%, 51/178). Sixteen of 33 patients detected with bacteria had cavities (48.5%, 16/33) and 35 of 145 patients detected with bacteria had no cavities (24.1%, 35/145). The difference between the 2 groups was statistically significant (χ2=7.795, P=0.005). According to the pathogenic bacteria, 38 patients were cured (74.51%, 38/51), and according to the CT imaging features 81 patients were cured (71.05%, 81/114). No statistically significant difference was found between them (χ2=0.209, P=0.647). Conclusions Treatment effect of CAP based on HRCT findings is not inferior to treatment effect guided by microbial characterization. PMID:27031210

  15. Microcomputer-based digital image processing - A tutorial package for exploration geologists

    NASA Technical Reports Server (NTRS)

    Harrington, J. A., Jr.; Cartin, K. F.

    1985-01-01

    An Apple II microcomputer-based software package for analysis of digital data developed at the University of Oklahoma, the Digital Image Analysis System (DIAS), provides a relatively low-cost, portable alternative to large, dedicated minicomputers for digital image processing education. Digital processing techniques for analysis of Landsat MSS data and a series of tutorial exercises for exploration geologists are described and evaluated. DIAS allows in-house training that does not interfere with computer-based prospect analysis objectives.

  16. Effect of the Availability of Prior Full-Field Digital Mammography and Digital Breast Tomosynthesis Images on the Interpretation of Mammograms

    PubMed Central

    Catullo, Victor J.; Chough, Denise M.; Ganott, Marie A.; Kelly, Amy E.; Shinde, Dilip D.; Sumkin, Jules H.; Wallace, Luisa P.; Bandos, Andriy I.; Gur, David

    2015-01-01

    Purpose To assess the effect of and interaction between the availability of prior images and digital breast tomosynthesis (DBT) images in decisions to recall women during mammogram interpretation. Materials and Methods Verbal informed consent was obtained for this HIPAA-compliant institutional review board–approved protocol. Eight radiologists independently interpreted twice deidentified mammograms obtained in 153 women (age range, 37–83 years; mean age, 53.7 years ± 9.3 [standard deviation]) in a mode by reader by case-balanced fully crossed study. Each study consisted of current and prior full-field digital mammography (FFDM) images and DBT images that were acquired in our facility between June 2009 and January 2013. For one reading, sequential ratings were provided by using (a) current FFDM images only, (b) current FFDM and DBT images, and (c) current FFDM, DBT, and prior FFDM images. The other reading consisted of (a) current FFDM images only, (b) current and prior FFDM images, and (c) current FFDM, prior FFDM, and DBT images. Fifty verified cancer cases, 60 negative and benign cases (clinically not recalled), and 43 benign cases (clinically recalled) were included. Recall recommendations and interaction between the effect of prior FFDM and DBT images were assessed by using a generalized linear model accounting for case and reader variability. Results Average recall rates in noncancer cases were significantly reduced with the addition of prior FFDM images by 34% (145 of 421) and 32% (106 of 333) without and with DBT images, respectively (P < .001). However, this recall reduction was achieved at the cost of a corresponding 7% (23 of 345) and 4% (14 of 353) reduction in sensitivity (P = .006). In contrast, availability of DBT images resulted in a smaller reduction in recall rates (false-positive interpretations) of 19% (76 of 409) and 26% (71 of 276) without and with prior FFDM images, respectively (P = .001). Availability of DBT images resulted in 4% (15 of

  17. Dual wavelength digital holography for 3D particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Grare, S.; Coëtmellec, S.,; Allano, D.; Grehan, G.; Brunel, M.; Lebrun, D.

    2015-02-01

    A multi-exposure digital in-line hologram of a moving particle field is recorded by two different wavelengths and at different times. As a result, during the reconstruction step, each hologram can be independently and accurately reconstructed for each wavelength. This procedure enables avoiding the superimposition of particles images that may be close to each other in multi-exposure holography. The feasibility is demonstrated by using a standard particle sizing reticle and shows the potential of this method for particle velocity measurement.

  18. Evaluation of Fiber Reinforced Cement Using Digital Image Correlation

    PubMed Central

    Melenka, Garrett W.; Carey, Jason P.

    2015-01-01

    The effect of short fiber reinforcements on the mechanical properties of cement has been examined using a splitting tensile – digital image correlation (DIC) measurement method. Three short fiber reinforcement materials have been used in this study: fiberglass, nylon, and polypropylene. The method outlined provides a simple experimental setup that can be used to evaluate the ultimate tensile strength of brittle materials as well as measure the full field strain across the surface of the splitting tensile test cylindrical specimen. Since the DIC measurement technique is a contact free measurement this method can be used to assess sample failure. PMID:26039590

  19. Digital Volume Imaging of the PEFC Gas Diffusion Layer

    SciTech Connect

    Mukherjee, Partha P

    2010-01-01

    The gas diffusion layer (GDL) plays a key role in the overall performance/durability of a polymer electrolyte fuel cell (PEFC). Of profound importance, especially in the context of water management and flooding phenomena, is the influence of the underlying pore morphology and wetting characteristics of the GDL microstructure. In this article, we present the digital volumetric imaging (DVI) technique in order to generate the 3-D carbon paper GDL microstructure. The internal pore structure and the local microstructural variations in terms of fiber alignment and fiber/binder distributions are investigated using the several 3-D thin sections of the sample obtained from DVI.

  20. Digital volume imaging of the PEFC gas diffusion layer

    SciTech Connect

    Borup, Rodney L; Mukundan, Rangachary; Mukherjee, Partha; Shim, Eunkyoung

    2010-01-01

    The gas diffusion layer (GDL) plays a key role in the overall performance/durability of a polymer electrolyte fuel cell (PEFC). Of profound importance, especially in the context of water management and flooding phenomena, is the influence of the underlying pore morphology and wetting characteristics Of the GDL microstructure. In this article, we present the digital volumetric imaging (DVI) technique in order to generate the 3-D carbon paper GDL microstructure. The internal pore structure and the local microstructural variations in terms of fiber alignment and fiber/binder distributions are investigated using the several 3-D thin sections of the sample obtained from DVI.

  1. Toward Digital Staining using Imaging Mass Spectrometry and Random Forests

    PubMed Central

    Hanselmann, Michael; Köthe, Ullrich; Kirchner, Marc; Renard, Bernhard Y.; Amstalden, Erika R.; Glunde, Kristine; Heeren, Ron M. A.; Hamprecht, Fred A.

    2009-01-01

    We show on Imaging Mass Spectrometry (IMS) data that the Random Forest classifier can be used for automated tissue classification and that it results in predictions with high sensitivities and positive predictive values, even when inter-sample variability is present in the data. We further demonstrate how Markov Random Fields and vector-valued median filtering can be applied to reduce noise effects to further improve the classification results in a post-hoc smoothing step. Our study gives clear evidence that digital staining by means of IMS constitutes a promising complement to chemical staining techniques. PMID:19469555

  2. Effects of Image Compression on Automatic Count of Immunohistochemically Stained Nuclei in Digital Images

    PubMed Central

    López, Carlos; Lejeune, Marylène; Escrivà, Patricia; Bosch, Ramón; Salvadó, Maria Teresa; Pons, Lluis E.; Baucells, Jordi; Cugat, Xavier; Álvaro, Tomás; Jaén, Joaquín

    2008-01-01

    This study investigates the effects of digital image compression on automatic quantification of immunohistochemical nuclear markers. We examined 188 images with a previously validated computer-assisted analysis system. A first group was composed of 47 images captured in TIFF format, and other three contained the same images converted from TIFF to JPEG format with 3×, 23× and 46× compression. Counts of TIFF format images were compared with the other three groups. Overall, differences in the count of the images increased with the percentage of compression. Low-complexity images (≤100 cells/field, without clusters or with small-area clusters) had small differences (<5 cells/field in 95–100% of cases) and high-complexity images showed substantial differences (<35–50 cells/field in 95–100% of cases). Compression does not compromise the accuracy of immunohistochemical nuclear marker counts obtained by computer-assisted analysis systems for digital images with low complexity and could be an efficient method for storing these images. PMID:18755997

  3. Image quality degradation and retrieval errors introduced by registration and interpolation of multispectral digital images

    SciTech Connect

    Henderson, B.G.; Borel, C.C.; Theiler, J.P.; Smith, B.W.

    1996-04-01

    Full utilization of multispectral data acquired by whiskbroom and pushbroom imagers requires that the individual channels be registered accurately. Poor registration introduces errors which can be significant, especially in high contrast areas such as boundaries between regions. We simulate the acquisition of multispectral imagery in order to estimate the errors that are introduced by co-registration of different channels and interpolation within the images. We compute the Modulation Transfer Function (MTF) and image quality degradation brought about by fractional pixel shifting and calculate errors in retrieved quantities (surface temperature and water vapor) that occur as a result of interpolation. We also present a method which might be used to estimate sensor platform motion for accurate registration of images acquired by a pushbroom scanner.

  4. Analysis of the quality of image data acquired by the LANDSAT-4 Thematic Mapper and Multispectral Scanners

    NASA Technical Reports Server (NTRS)

    Colwell, R. N. (Principal Investigator)

    1984-01-01

    The geometric quality of TM film and digital products is evaluated by making selective photomeasurements and by measuring the coordinates of known features on both the TM products and map products. These paired observations are related using a standard linear least squares regression approach. Using regression equations and coefficients developed from 225 (TM film product) and 20 (TM digital product) control points, map coordinates of test points are predicted. The residual error vectors and analysis of variance (ANOVA) were performed on the east and north residual using nine image segments (blocks) as treatments. Based on the root mean square error of the 223 (TM film product) and 22 (TM digital product) test points, users of TM data expect the planimetric accuracy of mapped points to be within 91 meters and within 117 meters for the film products, and to be within 12 meters and within 14 meters for the digital products.

  5. Recent developments at JPL in the application of digital image processing techniques to astronomical images

    NASA Technical Reports Server (NTRS)

    Lorre, J. J.; Lynn, D. J.; Benton, W. D.

    1976-01-01

    Several techniques of a digital image-processing nature are illustrated which have proved useful in visual analysis of astronomical pictorial data. Processed digital scans of photographic plates of Stephans Quintet and NGC 4151 are used as examples to show how faint nebulosity is enhanced by high-pass filtering, how foreground stars are suppressed by linear interpolation, and how relative color differences between two images recorded on plates with different spectral sensitivities can be revealed by generating ratio images. Analyses are outlined which are intended to compensate partially for the blurring effects of the atmosphere on images of Stephans Quintet and to obtain more detailed information about Saturn's ring structure from low- and high-resolution scans of the planet and its ring system. The employment of a correlation picture to determine the tilt angle of an average spectral line in a low-quality spectrum is demonstrated for a section of the spectrum of Uranus.

  6. Digital Earth Watch And Picture Post Network: Measuring The Environment Through Digital Images

    NASA Astrophysics Data System (ADS)

    Schloss, A. L.; Beaudry, J.; Pickle, J.; Carrera, F.

    2012-12-01

    Digital Earth Watch (DEW) involves individuals, schools, organizations and communities in a systematic monitoring project of their local environment, especially vegetation health. The program offers people the means to join the Picture Post network and to study and analyze their own findings using DEW software. A Picture Post is an easy-to-use and inexpensive platform for repeatedly taking digital photographs as a standardized set of images of the entire 360° landscape, which then can be shared over the Internet on the Picture Post website. This simple concept has the potential to create a wealth of information and data on changing environmental conditions, which is important for a society grappling with the effects of environmental change. Picture Posts may be added by anyone interested in monitoring a particular location. The value of a Picture Post is in the commitment of participants to take repeated photographs - monthly, weekly, or even daily - to build up a long-term record over many years. This poster will show examples of Picture Post pictures being used for monitoring and research applications, and a DEW mobile app for capturing repeat digital photographs at a virtual post. We invite individuals, schools, informal education centers, groups and communities to join.; A new post and its website. ; Creating a virtual post using the mobile app.

  7. Terrestrial scanning or digital images in inventory of monumental objects? - case study

    NASA Astrophysics Data System (ADS)

    Markiewicz, J. S.; Zawieska, D.

    2014-06-01

    Cultural heritage is the evidence of the past; monumental objects create the important part of the cultural heritage. Selection of a method to be applied depends on many factors, which include: the objectives of inventory, the object's volume, sumptuousness of architectural design, accessibility to the object, required terms and accuracy of works. The paper presents research and experimental works, which have been performed in the course of development of architectural documentation of elements of the external facades and interiors of the Wilanów Palace Museum in Warszawa. Point clouds, acquired from terrestrial laser scanning (Z+F 5003h) and digital images taken with Nikon D3X and Hasselblad H4D cameras were used. Advantages and disadvantages of utilisation of these technologies of measurements have been analysed with consideration of the influence of the structure and reflectance of investigated monumental surfaces on the quality of generation of photogrammetric products. The geometric quality of surfaces obtained from terrestrial laser scanning data and from point clouds resulting from digital images, have been compared.

  8. Analysis of the structural behavior of a membrane using digital image processing

    NASA Astrophysics Data System (ADS)

    Jurjo, Daniel Leonardo Braga Rodriguez; Magluta, Carlos; Roitman, Ney; Batista Gonçalves, Paulo

    2015-03-01

    This article presents a methodology for the experimental analysis of thin membranes using digital image processing techniques. The methodology is particularly suitable for structures that cannot be monitored using conventional systems, particularly those systems that involve contact with the structure. This methodology consists of a computer vision system that integrates the digital image acquisition and processing techniques on-line using special programming routines. Because the membrane analyzed is very thin and displays large displacements/strains, the use of any conventional sensor based on contact with the structure would not be possible. The methodology permits the measurement of large displacements at several points of the membrane simultaneously, thus enabling the acquisition of the global displacement field. The accuracy of the acquired displacement field is a function of the number of cameras and measured points. The second step is to estimate the strains and stresses on the membrane from the measured displacements. The basic idea of the methodology is to generate global two-dimensional functions that describe the strains and stresses at any point of the membrane. Two constitutive models are considered in the analysis: the Hookean and the neo-Hookean models. Favorable comparisons between the experimental and numerical results attest to the accuracy of the proposed experimental procedure, which can be used for both artificial and natural membranes.

  9. American College of Radiology Imaging Network digital mammographic imaging screening trial: objectives and methodology.

    PubMed

    Pisano, Etta D; Gatsonis, Constantine A; Yaffe, Martin J; Hendrick, R Edward; Tosteson, Anna N A; Fryback, Dennis G; Bassett, Lawrence W; Baum, Janet K; Conant, Emily F; Jong, Roberta A; Rebner, Murray; D'Orsi, Carl J

    2005-08-01

    This study was approved by the Institutional Review Board (IRB) of the American College of Radiology Imaging Network (ACRIN) and each participating site and by the IRB and the Cancer Therapy Evaluation Program at the National Cancer Institute. The study was monitored by an independent Data Safety and Monitoring Board, which received interim analyses of data to ensure that the study would be terminated early if indicated by trends in the outcomes. The ACRIN, which is funded by the National Cancer Institute, conducted the Digital Mammographic Imaging Screening Trial (DMIST) primarily to compare the diagnostic accuracy of digital and screen-film mammography in asymptomatic women presenting for screening for breast cancer. Over the 25.5 months of enrollment, a total of 49 528 women were included at the 33 participating sites, which used five different types of digital mammography equipment. All participants underwent both screen-film and digital mammography. The digital and screen-film mammograms of each subject were independently interpreted by two radiologists. If findings of either examination were interpreted as abnormal, subsequent work-up occurred according to the recommendations of the interpreting radiologist. Breast cancer status was determined at biopsy or follow-up mammography 11-15 months after study entry. In addition to the measurement of diagnostic accuracy by using the interpretations of mammograms at the study sites, DMIST included evaluations of the relative cost-effectiveness and quality-of-life effects of digital versus screen-film mammography. Six separate reader studies using the de-identified archived DMIST mammograms will also assess the diagnostic accuracy of each of the individual digital mammography machines versus screen-film mammography machines, the effect of breast density on diagnostic accuracy of digital and screen-film mammography, and the effect of different rates of breast cancer on the diagnostic accuracy in a reader study. PMID

  10. Robust digital image inpainting algorithm in the wireless environment

    NASA Astrophysics Data System (ADS)

    Karapetyan, G.; Sarukhanyan, H. G.; Agaian, S. S.

    2014-05-01

    Image or video inpainting is the process/art of retrieving missing portions of an image without introducing undesirable artifacts that are undetectable by an ordinary observer. An image/video can be damaged due to a variety of factors, such as deterioration due to scratches, laser dazzling effects, wear and tear, dust spots, loss of data when transmitted through a channel, etc. Applications of inpainting include image restoration (removing laser dazzling effects, dust spots, date, text, time, etc.), image synthesis (texture synthesis), completing panoramas, image coding, wireless transmission (recovery of the missing blocks), digital culture protection, image de-noising, fingerprint recognition, and film special effects and production. Most inpainting methods can be classified in two key groups: global and local methods. Global methods are used for generating large image regions from samples while local methods are used for filling in small image gaps. Each method has its own advantages and limitations. For example, the global inpainting methods perform well on textured image retrieval, whereas the classical local methods perform poorly. In addition, some of the techniques are computationally intensive; exceeding the capabilities of most currently used mobile devices. In general, the inpainting algorithms are not suitable for the wireless environment. This paper presents a new and efficient scheme that combines the advantages of both local and global methods into a single algorithm. Particularly, it introduces a blind inpainting model to solve the above problems by adaptively selecting support area for the inpainting scheme. The proposed method is applied to various challenging image restoration tasks, including recovering old photos, recovering missing data on real and synthetic images, and recovering the specular reflections in endoscopic images. A number of computer simulations demonstrate the effectiveness of our scheme and also illustrate the main properties

  11. 3D robust digital image correlation for vibration measurement.

    PubMed

    Chen, Zhong; Zhang, Xianmin; Fatikow, Sergej

    2016-03-01

    Discrepancies of speckle images under dynamic measurement due to the different viewing angles will deteriorate the correspondence in 3D digital image correlation (3D-DIC) for vibration measurement. Facing this kind of bottleneck, this paper presents two types of robust 3D-DIC methods for vibration measurement, SSD-robust and SWD-robust, which use a sum of square difference (SSD) estimator plus a Geman-McClure regulating term and a Welch estimator plus a Geman-McClure regulating term, respectively. Because the regulating term with an adaptive rejecting bound can lessen the influence of the abnormal pixel data in the dynamical measuring process, the robustness of the algorithm is enhanced. The robustness and precision evaluation experiments using a dual-frequency laser interferometer are implemented. The experimental results indicate that the two presented robust estimators can suppress the effects of the abnormality in the speckle images and, meanwhile, keep higher precision in vibration measurement in contrast with the traditional SSD method; thus, the SWD-robust and SSD-robust methods are suitable for weak image noise and strong image noise, respectively. PMID:26974624

  12. Determining approximate age of digital images using sensor defects

    NASA Astrophysics Data System (ADS)

    Fridrich, Jessica; Goljan, Miroslav

    2011-02-01

    The goal of temporal forensics is to establish temporal relationship among two or more pieces of evidence. In this paper, we focus on digital images and describe a method using which an analyst can estimate the acquisition time of an image given a set of other images from the same camera whose time ordering is known. This is achieved by first estimating the parameters of pixel defects, including their onsets, and then detecting their presence in the image under investigation. Both estimators are constructed using the maximum-likelihood principle. The accuracy and limitations of this approach are illustrated on experiments with three cameras. Forensic and law-enforcement analysts are expected to benefit from this technique in situations when the temporal data stored in the EXIF header is lost due to processing or editing images off-line or when the header cannot be trusted. Reliable methods for establishing temporal order between individual pieces of evidence can help reveal deception attempts of an adversary or a criminal. The causal relationship may also provide information about the whereabouts of the photographer.

  13. Establishing imaging sensor specifications for digital still cameras

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2007-02-01

    Digital Still Cameras, DSCs, have now displaced conventional still cameras in most markets. The heart of a DSC is thought to be the imaging sensor, be it Full Frame CCD, and Interline CCD, a CMOS sensor or the newer Foveon buried photodiode sensors. There is a strong tendency by consumers to consider only the number of mega-pixels in a camera and not to consider the overall performance of the imaging system, including sharpness, artifact control, noise, color reproduction, exposure latitude and dynamic range. This paper will provide a systematic method to characterize the physical requirements of an imaging sensor and supporting system components based on the desired usage. The analysis is based on two software programs that determine the "sharpness", potential for artifacts, sensor "photographic speed", dynamic range and exposure latitude based on the physical nature of the imaging optics, sensor characteristics (including size of pixels, sensor architecture, noise characteristics, surface states that cause dark current, quantum efficiency, effective MTF, and the intrinsic full well capacity in terms of electrons per square centimeter). Examples will be given for consumer, pro-consumer, and professional camera systems. Where possible, these results will be compared to imaging system currently on the market.

  14. Road Signs Detection and Recognition Utilizing Images and 3d Point Cloud Acquired by Mobile Mapping System

    NASA Astrophysics Data System (ADS)

    Li, Y. H.; Shinohara, T.; Satoh, T.; Tachibana, K.

    2016-06-01

    High-definition and highly accurate road maps are necessary for the realization of automated driving, and road signs are among the most important element in the road map. Therefore, a technique is necessary which can acquire information about all kinds of road signs automatically and efficiently. Due to the continuous technical advancement of Mobile Mapping System (MMS), it has become possible to acquire large number of images and 3d point cloud efficiently with highly precise position information. In this paper, we present an automatic road sign detection and recognition approach utilizing both images and 3D point cloud acquired by MMS. The proposed approach consists of three stages: 1) detection of road signs from images based on their color and shape features using object based image analysis method, 2) filtering out of over detected candidates utilizing size and position information estimated from 3D point cloud, region of candidates and camera information, and 3) road sign recognition using template matching method after shape normalization. The effectiveness of proposed approach was evaluated by testing dataset, acquired from more than 180 km of different types of roads in Japan. The results show a very high success in detection and recognition of road signs, even under the challenging conditions such as discoloration, deformation and in spite of partial occlusions.

  15. Registration of In Vivo Prostate Magnetic Resonance Images to Digital Histopathology Images

    NASA Astrophysics Data System (ADS)

    Ward, A. D.; Crukley, C.; McKenzie, C.; Montreuil, J.; Gibson, E.; Gomez, J. A.; Moussa, M.; Bauman, G.; Fenster, A.

    Early and accurate diagnosis of prostate cancer enables minimally invasive therapies to cure the cancer with less morbidity. The purpose of this work is to non-rigidly register in vivo pre-prostatectomy prostate medical images to regionally-graded histopathology images from post-prostatectomy specimens, seeking a relationship between the multi parametric imaging and cancer distribution and aggressiveness. Our approach uses image-based registration in combination with a magnetically tracked probe to orient the physical slicing of the specimen to be parallel to the in vivo imaging planes, yielding a tractable 2D registration problem. We measured a target registration error of 0.85 mm, a mean slicing plane marking error of 0.7 mm, and a mean slicing error of 0.6 mm; these results compare favourably with our 2.2 mm diagnostic MR image thickness. Qualitative evaluation of in vivo imaging-histopathology fusion reveals excellent anatomic concordance between MR and digital histopathology.

  16. Fourier transform digital holographic adaptive optics imaging system

    PubMed Central

    Liu, Changgeng; Yu, Xiao; Kim, Myung K.

    2013-01-01

    A Fourier transform digital holographic adaptive optics imaging system and its basic principles are proposed. The CCD is put at the exact Fourier transform plane of the pupil of the eye lens. The spherical curvature introduced by the optics except the eye lens itself is eliminated. The CCD is also at image plane of the target. The point-spread function of the system is directly recorded, making it easier to determine the correct guide-star hologram. Also, the light signal will be stronger at the CCD, especially for phase-aberration sensing. Numerical propagation is avoided. The sensor aperture has nothing to do with the resolution and the possibility of using low coherence or incoherent illumination is opened. The system becomes more efficient and flexible. Although it is intended for ophthalmic use, it also shows potential application in microscopy. The robustness and feasibility of this compact system are demonstrated by simulations and experiments using scattering objects. PMID:23262541

  17. Tennis ball fuzziness: assessing textile surface roughness using digital imaging

    NASA Astrophysics Data System (ADS)

    Steele, C.; Jones, R.; Leaney, P. G.

    2006-06-01

    Wear plays an important role in the game of tennis as it affects both ball performance and player perceived ball quality. Visual appearance can be used in ball differentiation, but has so far been limited to subjective assessments used to estimate ball wear and performance characteristics. A metric for ball surface condition will allow performance and perception data from varied testing set-ups to be objectively compared and analysed. A versatile new method of assessing surface roughness using digital imaging has been developed to allow the quantitative assessment of tennis ball condition. This metric allows manufacturers and researchers to predict ball performance and player perception from worn ball samples, developing acceptable wear limits. In the successful implementation of this metric, several key factors, including lighting, image thresholding, algorithm implementation and camera specifications, were identified to aid future alternative implementations.

  18. Advances in digital printing and quality considerations of digitally printed images

    NASA Astrophysics Data System (ADS)

    Waes, Walter C.

    1997-02-01

    The traditional 'graphic arts' market has changed very rapidly. It has been only ten years now since Aldus introduced its 'PageMaker' software for text and layout. The platform used was Apple-Mac, which became also the standard for many other graphic applications. The so-called high-end workstations disappeared. This was the start for what later was called: the desk top publishing revolution. At the same time, image scanning became also user-friendly and heavy duty scanners were reduced to desktop-size. Color- reproduction became a commodity product. Since then, the pre-press industry has been going through a technical nightmare, trying to keep up with the digital explosion. One after another, tasks and crafts of pre-press were being transformed by digital technologies. New technologies in this field came almost too fast for many people to adapt. The next digital revolution will be for the commercial printers. All the reasons are explained later in this document. There is now a definite need for a different business-strategy and a new positioning in the electronic media-world. Niches have to be located for new graphic arts- applications. Electronic services to-and-from originators' and executors environments became a requirement. Data can now flow on-line between the printer and the originator of the job. It is no longer the pre-press shop who is controlling this. In many cases, electronic data goes between the print-buyer or agency and the printer. High power communication-systems with accepted standard color- management are transforming the printer, and more particularly, the pre-press shop fatally. The new digital printing market, now in the beginning of its expected full expansion, has to do with growing requests coming from agencies and other print-buyers for: (1) short-run printing; (2) print-on-demand approximately in-time; (3) personalization or other forms of customization; (4) quick turnaround.

  19. Stigma models: Testing hypotheses of how images of Nevada are acquired and values are attached to them

    SciTech Connect

    Jenkins-Smith, H.C.

    1994-12-01

    This report analyzes data from surveys on the effects that images associated with nuclear power and waste (i.e., nuclear images) have on people`s preference to vacation in Nevada. The analysis was stimulated by a model of imagery and stigma which assumes that information about a potentially hazardous facility generates signals that elicit negative images about the place in which it is located. Individuals give these images negative values (valences) that lessen their desire to vacation, relocate, or retire in that place. The model has been used to argue that the proposed Yucca Mountain high-level nuclear waste repository could elicit images of nuclear waste that would stigmatize Nevada and thus impose substantial economic losses there. This report proposes a revised model that assumes that the acquisition and valuation of images depend on individuals` ideological and cultural predispositions and that the ways in which new images will affect their preferences and behavior partly depend on these predispositions. The report tests these hypotheses: (1) individuals with distinct cultural and ideological predispositions have different propensities for acquiring nuclear images, (2) these people attach different valences to these images, (3) the variations in these valences are important, and (4) the valences of the different categories of images within an individual`s image sets for a place correlate very well. The analysis largely confirms these hypotheses, indicating that the stigma model should be revised to (1) consider the relevant ideological and cultural predispositions of the people who will potentially acquire and attach value to the image, (2) specify the kinds of images that previously attracted people to the host state, and (3) consider interactions between the old and potential new images of the place. 37 refs., 18 figs., 17 tabs.

  20. Implementation of real-time digital endoscopic image processing system

    NASA Astrophysics Data System (ADS)

    Song, Chul Gyu; Lee, Young Mook; Lee, Sang Min; Kim, Won Ky; Lee, Jae Ho; Lee, Myoung Ho

    1997-10-01

    Endoscopy has become a crucial diagnostic and therapeutic procedure in clinical areas. Over the past four years, we have developed a computerized system to record and store clinical data pertaining to endoscopic surgery of laparascopic cholecystectomy, pelviscopic endometriosis, and surgical arthroscopy. In this study, we developed a computer system, which is composed of a frame grabber, a sound board, a VCR control board, a LAN card and EDMS. Also, computer system controls peripheral instruments such as a color video printer, a video cassette recorder, and endoscopic input/output signals. Digital endoscopic data management system is based on open architecture and a set of widely available industry standards; namely Microsoft Windows as an operating system, TCP/IP as a network protocol and a time sequential database that handles both images and speech. For the purpose of data storage, we used MOD and CD- R. Digital endoscopic system was designed to be able to store, recreate, change, and compress signals and medical images. Computerized endoscopy enables us to generate and manipulate the original visual document, making it accessible to a virtually unlimited number of physicians.