Independent and automatic imageprocessing is a fundamental objective of the computer vision community. Understanding the role of the eye movement scanpath in human vision is an important step toward the achievement o...
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Independent and automatic imageprocessing is a fundamental objective of the computer vision community. Understanding the role of the eye movement scanpath in human vision is an important step toward the achievement of this objective. This top-down model of higher human vision is a new approach to bottom-up imageprocessingalgorithms and provides an important new metric and tool in computer vision. We have demonstrated that a small and manageable collection of imageprocessingalgorithms, experimentally selected and then combined together can serve in a task such as predicting human eye fixations identifying geological features. Thus, automatic picture analysis based upon human vision could be an essential element in planetary exploration.
video sensors become particularly important in traffic applications mainly due to their fast response. easy installation. operation and maintenance, and their ability to monitor wide areas. Research in several fields ...
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video sensors become particularly important in traffic applications mainly due to their fast response. easy installation. operation and maintenance, and their ability to monitor wide areas. Research in several fields of traffic applications has resulted in a wealth of video processing and analysis methods. Two of the most demanding and widely studied applications relate to traffic monitoring and automatic vehicle guidance. In general. systems developed for these areas must integrate. amongst then, other tasks, the analysis of their static environment (automatic lane finding) and the detection of static or moving obstacles (object detection) within their space of interest. In this paper we present an overview of imageprocessing and analysis tools used in these applications and we relate these tools with complete systems developed for specific traffic applications. More specifically. we categorize processing methods based on the intrinsic organization of their input data (feature-driven, area-driven. or model-based) and the domain of processing (spatial/franic or temporal/video). Furthermore. we discriminate between the cases of static and mobile camera. Based on this categorization of processing tools, we present representative systems that have been deployed for operation. Thus. the purpose of the paper is threefold. First. to classify image-processing methods used in traffic applications. Second, to provide the advantages and disadvantages of these algorithms. Third, from this integrated consideration, to attempt an evaluation of shortcomings and general needs in this field of active research. (C) 2003 Elsevier Science B.v. All rights reserved.
In recent years a new class of Synthetic Aperture Radar (SAR) systems, using low frequencies, have emerged. The combination of low frequencies with high bandwidths allows a variety of new applications. Several new fie...
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ISBN:
(纸本)0819446653
In recent years a new class of Synthetic Aperture Radar (SAR) systems, using low frequencies, have emerged. The combination of low frequencies with high bandwidths allows a variety of new applications. Several new fields arise in forestry, biomass estimation and in archaeological and geological exploration. The P-band SAR technology benefits from technological advances in antenna design, low noise amplifiers, band pass filters, digital receiver technology, as well as new processingalgorithms [1], [2]. For all the new applications of an airborne P-band SAR system, the high-resolution imaging is an important parameter, but it cannot be easily achieved with conventional processing techniques. In this paper, the performance and limitations of the Extended Chirp Scaling (ECS) algorithm and wavenumber domain Omega-K processing algorithm are analysed and discussed. Additionally, modifications of both algorithms are proposed, which optimise the respective algorithm for processing low frequency, wide-beam and wide-band SAR data. Despite of the inherent limitations of the above mentioned processingalgorithms, a deterministic phase error, called "digital phase error", due to digital signal processing characteristics is formulated and its effect to the processed SAR data is analytically described. The analysis is carried out, using simulated low frequency airborne SAR data.
A device has been designed for off-line optical paper inspection and quality control of stripes and holes in the cigarette paper. Hardware description is first presented including main paper characteristics to be meas...
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ISBN:
(纸本)0819450146
A device has been designed for off-line optical paper inspection and quality control of stripes and holes in the cigarette paper. Hardware description is first presented including main paper characteristics to be measured. Typical paper stripe and holes structures are then discussed with imageprocessing and analysis considerations to discriminate these structures, focusing in the problems derived from the small area of holes and of their internal structure that is analyzed with a confocal microscope. algorithms for imageprocessing and analysis are described. These algorithms involve equalization, binarization, stripes structure detection, holes distribution and statistics.
Printronix, Inc. uses scanner-based imagesystems to perform print quality measurements for line-matrix printers. The size of the image samples and image definition required make commercial scanners convenient to use....
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ISBN:
(纸本)0819449415
Printronix, Inc. uses scanner-based imagesystems to perform print quality measurements for line-matrix printers. The size of the image samples and image definition required make commercial scanners convenient to use. The imageprocessing is relatively well defined, and we are able to simplify many of the calculations into hardware equations and v code. The process of rapidly prototyping the system using DSP based 'c' code gets the algorithms well defined early in the development cycle. Once a working system is defined. the rest of the process involves splitting the task Lip for the FPGA and the DSP implementation. Deciding which of the two to use. the DSP or the FPGA, is a simple matter of trial benchmarking. There are two kinds of benchmarking: One for speed, and the other for memory. The more memory intensive algorithms should run in the DSP, and the simple real time tasks can use the FPGA most effectively. Once the task is split, we can decide which platform the algorithm should be executed. This involves prototyping all the code in the DSP, then timing various blocks of the algorithm. Slow routines can be optimized using the compiler tools. and if further reduction in time is needed, into tasks that the FPGA can perform.
New adaptive varying window size gradient estimation methods for edge detection are presented in this work. The nonparametric Local Polynomial Approximation (LPA) method is used to define gradient estimation kernels o...
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ISBN:
(纸本)0819448141
New adaptive varying window size gradient estimation methods for edge detection are presented in this work. The nonparametric Local Polynomial Approximation (LPA) method is used to define gradient estimation kernels or masks, which in conjunction with varying adaptive window size selection, carried out by the Intersection of Confidence Intervals (ICI) for each pixel, let us obtain algorithms which are adaptive to unknown smoothness and nearly optimal in the point-wise risk for estimating the intensity function and its derivatives. Several-existing strategies using a constant window size of the convolutional kernel of edge detection have been upgraded to become varying window size techniques, first through the use of LPA for defining the gradient convolutional kernels of different sizes and second through ICI for the selection of the best estimate which balances the bias-variance trade-off in a point wise fashion for the whole stream of data. Comparisons with invariant window size edge detection schemes show the superiority of the presented methods, even over computationally more expensive techniques of edge detection.
We discuss wavelet filter parametrization as a means to add security to wavelet-based watermarking schemes. It turns out that our proposed scheme is resistant to unauthorized detection and unauthorized removal attacks...
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We discuss wavelet filter parametrization as a means to add security to wavelet-based watermarking schemes. It turns out that our proposed scheme is resistant to unauthorized detection and unauthorized removal attacks and is equally robust as compared to the use of standard wavelet filters in case the underlying watermarking scheme is spread-spectrum based. Quantization-based watermarking techniques are not suited to be enhanced by this approach. We assess the security, quality and robustness of our approach in the light of four selected watermarking algorithms. Furthermore, we present an attack tailored to exploit a common weakness in image-adaptive watermarking and propose filter parametrization as a suitable countermeasure. (C) 2003 Elsevier B.v. All rights reserved.
While evaluating the performance of imageprocessingalgorithms, the starting point is often the acquired image. However, in practice, several factors, extrinsic to the actual algorithm, affect its performance. These ...
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ISBN:
(纸本)0819448117
While evaluating the performance of imageprocessingalgorithms, the starting point is often the acquired image. However, in practice, several factors, extrinsic to the actual algorithm, affect its performance. These factors depend largely on the features of the acquisition system. This paper focuses on some of the key factors that affect algorithm performance, and attempts to provide some insight into defining "optimal" system features for best performance. The system features studied in depth in the paper are camera type, camera SNR, pixel size, bit-depth and system illumination. We were primarily interested in determining the effect of each of these factors on system performance. Towards this end, we designed an experiment to measure performance on a precision measurement system using several different cameras under varying illumination settings. From the results of the experiment, we observed that the variation in performance was greater for the same algorithm under different test system configurations, than for different algorithms under the same system configuration. Using these results as the basis, we discuss at length the combination of features that contributes to an optimal system configuration for a given purpose. We expect this work to have relevance to researchers in all areas of imageprocessing who want to optimize the performance of their algorithms when ported to actual systems.
The number of applications that require parallel and high-performance computing techniques has diminished in recent years due to to the continuing increase in power of PC, workstation and mono-processor systems. Howev...
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The number of applications that require parallel and high-performance computing techniques has diminished in recent years due to to the continuing increase in power of PC, workstation and mono-processor systems. However, Geographic information systems (GIS) still provide a resource-hungry application domain that can make good use of parallel techniques. We describe our work with geographical systems for environmental and defence applications and some of the algorithms and techniques we have deployed to deliver high-performance prototype systems that can deal with large data sets. GIS applications are often run operationally as part of decision support systems with both a human interactive component as well as large scale batch or server-based components. Parallel computing technology embedded in a distributed system therefore provides an ideal and practical solution for multi-site organisations and especially government agencies who need to extract the best value from bulk geographic data. We describe the distributed computing approaches we have used to integrate bulk data and metadata sources and the grid computing techniques we have used to embed parallel services in an operational infrastructure. We describe some of the parallel techniques we have used: for data assimilation;for image and map data processing;for data cluster analysis;and for data mining. We also discuss issues related to emerging standards for data exchange and design issues for integrating together data in a distributed ownership system. We include a historical review of our work in this area over the last decade which leads us to believe parallel computing will continue to play an important role in GIS. We speculate on algorithmic and systems issues for the future. (C) 2003 Published by Elsevier B.v.
For all application segments X-ray systems with flat-panel detectors increasingly enter the market. In digital radiography, mammography and cardiologic angiography flat-panel detectors are already well established whi...
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For all application segments X-ray systems with flat-panel detectors increasingly enter the market. In digital radiography, mammography and cardiologic angiography flat-panel detectors are already well established while they are made ready for market introduction in general angiography and fluoroscopy. Two flat-panel detector technologies are available. One technology is based on an indirect conversion process of X-rays while the other one uses a direct conversion method. For radiography and dynamic applications the indirect method provides substantial advantages, while the direct method has some benefits for mammography. In radiography and mammography flat-panel detectors lead to clear improvements with respect to workflow, image quality and dose reduction *** improvements are fostered by the immediate availability of the image, the large dynamic range and the high sensitivity to X-rays. New applications and the use of complex imageprocessingalgorithms have the potential to enlarge the present diagnostic range of applications. Up to now, image intensifiers are still the well-established technology for angiography and fluoroscopy. Nevertheless flat-panel detectors begin to enter this field, especially in cardiologic *** of flat-panel detectors such as the availability of distortion-free images, the excellent contrast resolution,the large dynamic range,the high sensitivity to X-rays and the usability in magnetic fields provide the basis for improved and new diagnostic and interventional methods.
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