We present a 1.3 megapixel CMOS active pixel sensor dedicated to industrial vision. It features both rolling and synchronous shutter. Full frame readouttime is 33 ms, and readout speed can be boosted by windowed regi...
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ISBN:
(纸本)0819448176
We present a 1.3 megapixel CMOS active pixel sensor dedicated to industrial vision. It features both rolling and synchronous shutter. Full frame readouttime is 33 ms, and readout speed can be boosted by windowed region of interest (ROI) readout. High dynamic range scenes can be captured using the double and multiples slope functionality. All operation modes and settings can be programmed over a serial or a parallel interface.
Defining criteria to determine precisely the boundaries of masses in mammograms is a difficulttask. the problem is compounded by the factthat most malignanttumors possess fuzzy boundaries with a slow and extended t...
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Defining criteria to determine precisely the boundaries of masses in mammograms is a difficulttask. the problem is compounded by the factthat most malignanttumors possess fuzzy boundaries with a slow and extended transition from a dense core region to the surrounding less-dense tissues. We propose two segmentation methods that incorporate fuzzy concepts. the first method determines the boundary of a mass or tumor by region growing after a preprocessing step based on fuzzy sets to enhance the region of interest (ROI). Contours provided by the method have demonstrated a good match with the contours drawn by a radiologist, as indicated by good agreement between the two sets of contours for 47 mammograms. the second segmentation method is a fuzzy region-growing method thattakes into accountthe uncertainty present around the boundaries of tumors. the difficult step of deciding on a crisp boundary is obviated in the proposed method. Measures of inhomogeneity computed from the pixels present in a suitably defined fuzzy ribbon have indicated potential use in classifying the masses and tumors as benign or malignant, with a sensitivity of 0.8 and a specificity of 0.9. (C) 2003 spie and ISt.
We have developed a CMOS vision chip, an image sensor with pixel-level signal processing, to replace photoreceptor cells in the retina. In this paper, we describe a pixel-level signal processing, which is to control o...
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ISBN:
(纸本)0819448176
We have developed a CMOS vision chip, an image sensor with pixel-level signal processing, to replace photoreceptor cells in the retina. In this paper, we describe a pixel-level signal processing, which is to control on the stimulus waveform and the amount of the electrical injection charge. Our CMOS vision chip is an array of a pixel, which consists of a photo detector, a pulse shaper, and a current stimulus circuit. the photo detector circuit generates a pulse frequency modulated (PFM) pulse;which frequency is proportional to the intensity of the incoming-light [1][2]. the PFM photo detector is also modified to restrictthe maximum frequency of PFM pulse signal for safety neural stimulation [3]. the PFM pulse signal should be converted into suitable waveform for efficient neural stimulation. We have employed a pulse shaper to generate one stimulus pulse from one PFM pulse. the pulse parameters (i.e., pulse duration, polarity, etc) of the output pulse signal are controlled by the external signal. For the electrical neural stimulus;the stimulus intensity is given by the amount of the electrical injection charge. the amount of the injection charge should be enough to evoke a phosphene but should be low to avoid the damage of the retinal tissue caused by the excess charge injection. In our prototyped CMOS vision chip, the stimulus current amplitude is used to control the amount of charge. the 6-bit binary-weighted digital-to-analog converter (DAC) with 2muA resolution is used to control the stimulus current amplitude.
We have developed digital signal processingalgorithms one of which realizes high-quality image with 520tV lines of horizontal resolution using a single-chip color 410k pixels-CCD and the other improves vertical resol...
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ISBN:
(纸本)081944409X
We have developed digital signal processingalgorithms one of which realizes high-quality image with 520tV lines of horizontal resolution using a single-chip color 410k pixels-CCD and the other improves vertical resolution in an electronic zoom. We have also developed a single-chip LSI realizing these algorithms in real-time and a highresolution surveillance camera with 520tV lines. these algorithms consist of three technologies as follows: 1) Chroma adaptive horizontal aperture compensation area by area 2) Edge adaptive color separation and new optical LPF with high MtF 3) Motion adaptive electronic zoom.
the primary focus of the Army's Science and technology (S&t) program is the maturation of technologies that enable fielding of Objective Force capabilities by decades end. the Networked Sensors for the Objecti...
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ISBN:
(纸本)0819444936
the primary focus of the Army's Science and technology (S&t) program is the maturation of technologies that enable fielding of Objective Force capabilities by decades end. the Networked Sensors for the Objective Force (NSOF) Advanced technology Demonstration (AtD), executed by the Army's CECOM Night Vision and electronics Sensors Directorate, will develop affordable sensor systems organic to the lower echelon warfighters. these sensors will help to fill gaps in the situational awareness picture derived solely on higher echelon intelligence sources, thus improving local situational awareness and battlefield understanding. In addition to unmanned air and ground vehicle-based sensor systems, the NSOF program will develop a distributed ground sensor (DGS) system to provide detection, classification, identification, tracking, and targeting capabilities against military vehicles and weapon systems. Key aspects of the DGS system include day/nightimaging, autonomous image capture, self-configuring and healing network architectures, jam-resistant communications, in-field data fusion, and robust command and control.
Most recent attempts at object segmentation have been based on object motion in video sequences. However, object segmentation in still images is more difficult. Without motion cues, other cues must be found. Edge dete...
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Most recent attempts at object segmentation have been based on object motion in video sequences. However, object segmentation in still images is more difficult. Without motion cues, other cues must be found. Edge detection algorithms are able to extract object contours from images, and were once thoughtto hold promise for object segmentation in still images. However, additional processing is needed to distinguish between object contours and other edges, such as those produced by textures. the alternative method of region growing (based on luminance or color) has also proven rather ineffective for object segmentation in natural images. In contrast, humans are very successful at object segmentation in still images, suggesting that a model of the early human visual system (HVS) might reveal useful methods for more robust object segmentation in still images. the research results presented in this paper are derived from an HVS model that includes models of type 1 and type 2 color contrast cells, and double opponent color contrast cells. By combining the outputs of these cells with edge detected images, object contours can be better distinguished from other contours (such as texture contours and shadow contours) thus providing enhanced object segmentation in cluttered images.
Potential threats caused by something like real fingers, which are called fake or artificial fingers, should be crucial for authentication based on fingerprintsystems. Security evaluation against attacks using such a...
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ISBN:
(纸本)0819444170
Potential threats caused by something like real fingers, which are called fake or artificial fingers, should be crucial for authentication based on fingerprintsystems. Security evaluation against attacks using such artificial fingers has been rarely disclosed. Only in patent literature, measures, such as "live and well" detection, against fake fingers have been proposed. However, the providers of fingerprintsystems usually do not mention whether or notthese measures are actually implemented in emerging fingerprintsystems for PCs or smart cards or portable terminals, which are expected to enhance the grade of personal authentication necessary for digital transactions. As researchers who are pursuing secure systems, we would like to discuss attacks using artificial fingers and conduct experimental research to clarify the reality. this paper reports that gummy fingers, namely artificial fingers that are easily made of cheap and readily available gelatin, were accepted by extremely high rates by 11 particular fingerprint devices with optical or capacitive sensors. We have used the molds, which we made by pressing our live fingers againstthem or by processing fingerprintimages from prints on glass surfaces, etc. We describe how to make the molds, and then show thatthe gummy fingers, which are made with these molds, can fool the fingerprint devices.
the human visual system has a lower spatial resolution in the periphery than in the fovea. this property may be useful to reduce system bandwidth in applications where the observers' fovea is allowed to scrutinize...
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the human visual system has a lower spatial resolution in the periphery than in the fovea. this property may be useful to reduce system bandwidth in applications where the observers' fovea is allowed to scrutinize a very small portion of a picture. For example, an image frame in a video or movie is presented for less than 100 milliseconds. When viewed with such a short duration, most parts of the frame is seen by the peripheral retina. Since the resolution of the spatial resolution is low, one could reduce information in image areas that will be viewed by the periphery without causing perceptible image degradation. the purpose here is to present a quantitative metric for evaluating the image quality for such non-uniform degradations, by considering visual performance in the periphery. According to this metric, the image difference between the degraded image and the original is decomposed into five levels of pyramid error images based on a measured or assumed fixation position. the contrast of each error image is scaled by a contrastthreshold map that is a function of spatial frequency, eccentricity, and image content. Finally, the perceived image degradation is calculated as the square root of the sum of the mean squared contrast over levels and color channels. Experiments were conducted to obtain subjective image quality with non-uniformly degraded images using two differentalgorithms. Five observers participated in the experiment and were instructed to rate the image quality on a ratio scale. the resulting image quality metric accounts for 92% of the variance in the image quality ratings. As a benchmark, RMS difference accounts for only 67% of the variance.
Designers of imagingsystems, imageprocessingalgorithms, etc., usually take for granted that methods for assessing perceived image quality produce unbiased estimates of the viewers' quality impression. Quality j...
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Designers of imagingsystems, imageprocessingalgorithms, etc., usually take for granted that methods for assessing perceived image quality produce unbiased estimates of the viewers' quality impression. Quality judgments, however, are affected by the judgment strategies induced by the experimental procedures. In this paper the results of two experiments are presented illustrating the influence judgment strategies can have on quality judgments. the first experiment concerns contextual effects due to the composition of the stimulus set. Subjects assessed the sharpness of two differently composed sets of blurred versions of one static image. the sharpness judgments for the blurred images present in both stimulus sets were found to be dependent on the composition of the set as well as the scaling technique employed. In the second experiment subjects assessed either the overall quality or the overall impairment of manipulated and standard JPEG-coded images containing two main artifacts. the results indicate a systematic difference between the quality and impairment judgments that could be interpreted as instruction-based different weighting of the two artifacts. Again, some influence of scaling technique was observed the results of both experiments underscore the important role judgment strategies play in the psychophysical evaluation of image quality. ignoring this influence on quality judgments may lead to invalid conclusions aboutthe viewers' impression of image quality. (C) 2001 spie and IS&t.
Many imageprocessing operations can be abstracted into matrix operations. With the help of matrix analysis, we can understand the inherent properties of the operations and thus design better algorithms. In this paper...
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Many imageprocessing operations can be abstracted into matrix operations. With the help of matrix analysis, we can understand the inherent properties of the operations and thus design better algorithms. In this paper, we propose a matrix decomposition method referred to as identity-plus-row decomposition, the decomposition is particularly useful in design of parallel projection algorithms on mesh-connected computers. Projection is a frequently used process in imageprocessing and visualization. In volume graphics, projection is used to render the essential content of a three-dimensional volume onto a two-dimensional image plane. For Radon transform, projection is used to transform the image space into a parameter space. By applying the identity-plus-row matrix decomposition method, we solve the data redistribution problem due to the irregular data access patterns present in those applications on single instruction stream, multiple data stream (SIMD) mesh-connected computers, developing fastalgorithms for volume rendering and Radon transform on SIMD mesh-connected computers. (C) 2001 spie and IS&t.
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