The authors apply a three-dimensional (3-D) linear least-squares (LS) prediction technique to the processing of digital subtraction angiography (DSA) image sequences. The main goal of this processing is the cancellati...
详细信息
The authors apply a three-dimensional (3-D) linear least-squares (LS) prediction technique to the processing of digital subtraction angiography (DSA) image sequences. The main goal of this processing is the cancellation of motion artifacts, which is a visual structured noise that appears in current DSA images. Two important issues are addressed by this technique. The first is the misregistration of the mask and the contrast image. The second is the temporal filtering of the DSA image sequence. Instead of treating these two issues separately, as in conventional DSA, the authors combine them into a 3-D LS prediction problem. Based on this approach they developed an efficient algorithm for the solution of normal equations. To match the image sequence physical characteristics, the authors have further optimized practical parameters of this algorithm. Actual patient data are used for the evaluation of this technique. Results show a significant improvement over the existing methods.< >
The paper presents an eye tracking system specifically designed for the recording of eye movements from the visitors of a museum. Eye movements are calculated from the images of a near infra-red camera viewing the eye...
详细信息
The paper presents an eye tracking system specifically designed for the recording of eye movements from the visitors of a museum. Eye movements are calculated from the images of a near infra-red camera viewing the eye during the presentation of a sequence of slides. Thereafter, the same slides are displayed with the scanning paths superimposed. Servo systems, ''intelligent'' imageprocessingalgorithms and interactive procedures have been implemented so that the eye tracker can operate on the general public without any technical supervision.
The authors propose a vLSI circuit design method which is derived from a functional decomposition of low-level imageprocessingalgorithms. In order to design high powerful architecture, the authors have been testing ...
详细信息
The authors propose a vLSI circuit design method which is derived from a functional decomposition of low-level imageprocessingalgorithms. In order to design high powerful architecture, the authors have been testing this functional approach quite extensively, and special-purpose circuits have already been developed. Finally from a broad class of various imageprocessingalgorithms and operators, the authors have defined a computational unit called a functional element. These elements are to be associated to form a mesh-connected programmable data flow computer. This data flow computer has been defined to obtain a straight mapping of the expressed algorithms on the basis of functional programming. Thus, high computing power can be easily obtained for real-time complex imageprocessing applications. Using the equivalent data flow graphs of the algorithms, this computer can help to determine whether a given combination of precisely specified IC operators would have the requested behavior, so that a special-purpose vLSI could be easily designed. Several examples of implementation onto this computer are shown in order to point out the salient concept and advantages of this approach.
The authors present new algorithms for the segmentation of speckled images, including synthetic aperture radar (SAR) images. These algorithms are based on a hierarchical random field model proposed for speckled images...
详细信息
The authors present new algorithms for the segmentation of speckled images, including synthetic aperture radar (SAR) images. These algorithms are based on a hierarchical random field model proposed for speckled images and a maximum a posteriori (MAP) segmentation using simulated annealing. Different versions of the model are developed to represent single or multilook and intensity or complex speckled images. Parameters of the speckle processes are estimated as part of the algorithm. The segmentation algorithms are implemented on a wide class of synthetically generated and actual speckled images. The results verify that significant improvement is obtained when multilook and complex image data are used for the segmentation.
The machine vision algorithms required to increase the accuracy of a manipulator to that of its resolution are presented. This high accuracy is required for laser programming of reconfigurable integrated circuits. An ...
详细信息
The machine vision algorithms required to increase the accuracy of a manipulator to that of its resolution are presented. This high accuracy is required for laser programming of reconfigurable integrated circuits. An application-specific integrated circuit has been fabricated that performs the time-critical aspects of the image recognition algorithms at video rates.
Many problems of geophysics, imageprocessing and time series analysis involve the problem of solving Toeplitz systems of equations. We present a fast parallel O (mn) algorithm that solves both square and over -determ...
详细信息
A large number of remote sensing studies in the Netherlands are performed using airborne sensors. At the present moment, a multitude of different sensors are available, covering a wide variety of application purposes....
详细信息
The authors attempt to summarize important parameters and procedures for verifying the measurement and recognition (classification) accuracy of machine vision algorithms/systems;to alert the machine vision research co...
详细信息
The authors attempt to summarize important parameters and procedures for verifying the measurement and recognition (classification) accuracy of machine vision algorithms/systems;to alert the machine vision research community to the current, very inadequate practice in this important area;and to propose some measures to improve this situation. Two example applications from the authors' practice are given in order to illustrate experimental verification procedures presented here. The motivation for the present work is based on the fact that machine vision systems are very hard to model or simulate accurately. It is concluded that realistic large-scale experiments are the most reliable means of verifying the measurement and recognition accuracy. However, it is claimed that in the machine vision (research) community, this verification is seldom done adequately.
The authors consider the problem of motion estimation from 3-D profiles with emphasis on the algorithm structure. For simplicity, the authors classify various versions of the algorithms based on the availability of th...
详细信息
The authors consider the problem of motion estimation from 3-D profiles with emphasis on the algorithm structure. For simplicity, the authors classify various versions of the algorithms based on the availability of the constraints such as object rigidity, point features, and matching correspondences. In addition to the analysis of the algorithms at various levels, one of the purposes of the present study is to describe the modifications and fundamental changes of the algorithm structure corresponding to the stages of the constraint availability. Motion estimation problems are classified into four categories, and simple examples are provided as potential applications.
A solid modeling system is described which permits efficient reasoning about scene models derived from edge images. The modeling system implements a hierarchical object structure, with points, lines, polygons, rigid o...
详细信息
A solid modeling system is described which permits efficient reasoning about scene models derived from edge images. The modeling system implements a hierarchical object structure, with points, lines, polygons, rigid objects, and articulated objects. User programs are able to freely manipulate these entities, without concern for the underlying representations. A set of parallel operations, described as graph grammar productions, makes it possible to separate the goals of parallel operations from the details of implementing multiple processes;this greatly simplifies the development of algorithms making use of these structures. It is expected that the architecture derived from these algorithms will be sufficiently flexible as to allow development of a wide variety of blackboard-based reasoning algorithms.
暂无评论