This paper concerns the influence of edge direction on the estimation of edge contrast and orientation. We show that the gradient estimated using radial filters is not affected by edge orientation. For non-radial filt...
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(纸本)0818672587
This paper concerns the influence of edge direction on the estimation of edge contrast and orientation. We show that the gradient estimated using radial filters is not affected by edge orientation. For non-radial filters the gradient can be affected by edge orientation. For instance, we find that the estimated edge orientation using a non-radial filter may be biased, even if the signal is noise-free. However, there are non-radial filters for which gradient is unaffected by edge orientation as in the case of radial filters. The properties of these functions are given in this paper. The results are illustrated by the study of the Canny, Deriche, and Shen & Castan detectors. We take into account discretization errors. These results give a clear indication of the effect of the rotation invariance property of an edge detector on its response, thus providing a more precise meaning for this property in edge detection.
A model based multiresolution, image segmentation technique which makes use of the velocity field information in phase contrast magnetic resonance (MR) angiograms, and an a priori assumption that locally, blood vessel...
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A model based multiresolution, image segmentation technique which makes use of the velocity field information in phase contrast magnetic resonance (MR) angiograms, and an a priori assumption that locally, blood vessels appear as line segments was implemented. The list structure of the resulting segmentation can be used efficiently in image analysis and processing. Within this segmentation, flow direction, vessel axis, diameter and velocity estimates can be made. The paper demonstrates its use in extracting vessels from patient data and in the calculation of pressure gradients in a model stenosis.
Morphological filters provide a very useful theoretical and practical tool for shape or size oriented imageprocessing. According to definition of increase and idempotence, the well known morphological filters are ope...
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Morphological filters provide a very useful theoretical and practical tool for shape or size oriented imageprocessing. According to definition of increase and idempotence, the well known morphological filters are opening, closing, opening, close-opening and their alternating series such as alternating sequential filters. In this article, four new kinds of morphological filters called composite morphological filters (CMFs) formed by the combination of opening and closing with image component itself are presented. Part of the CMFs in MMD procedure are used to get image components according to texture size distributions. Finally, an attempt is made to classify different textures using a feature taken from decomposed images by CMFs.
Preliminary studies concerned with the effects of sampling variation on the performance of imagerecognition systems are conducted to show that random perturbations in the sampling process lead to substantial deviatio...
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Preliminary studies concerned with the effects of sampling variation on the performance of imagerecognition systems are conducted to show that random perturbations in the sampling process lead to substantial deviations in measured features from an input image. Provided certain conditions are met, this variation can be exploited to improve recognition accuracy. Finally, three experiments demonstrating this approach are described in the context of step edge detection, simple patternrecognition, and OCR.
The proceedings contains 170 papers. Topics discussed include imageprocessing.image coding, labelling and classification, medical applications, motion, stereo and three dimensional, image analysis, image interpretat...
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The proceedings contains 170 papers. Topics discussed include imageprocessing.image coding, labelling and classification, medical applications, motion, stereo and three dimensional, image analysis, image interpretation, image coding and communications, shape description and recognition, imageprocessing.applications, computer architectures, image segmentation, neural networks, industrial inspection, filtering and morphology, texture and color, transport, security and remote sensing.
This paper reports on the results of a study using neural networks and the HSI (hue, saturation and intensity) colour model for the identification of areas, suitable for further imageprocessing. from bone marrow smea...
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This paper reports on the results of a study using neural networks and the HSI (hue, saturation and intensity) colour model for the identification of areas, suitable for further imageprocessing. from bone marrow smears. 25μm2 areas of the image were sparse sampled and this acted as the input to the neural networks. The classification ability of multi-layer perceptron (MLP) networks and radial basis function (RBF) networks were compared and it is was found that RBF networks proved to be superior for this task. It was also noted that the saturation plane was the least useful for the differentiation of suitable areas. By using the system and scanning the image on a pixel by pixel basis it was possible to produce 'masks' which identified areas worthy of further processing.
Seal identification is usually performed by hardmatching of human visual inspection. A computerprocessing.of the hardmatching is presented to identify a Chinese seal image. Seals of the author's own are used f o ...
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There is a large number of documents, including hand-printed maps, where useful information is lost if binarization is performed on the scanned image before further processing. For such documents, methods which utiliz...
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An image coder based on the singular value decomposition and vector quantization is presented. The singular values and singular vectors of image sub-blocks are computed at the encoder and quantized using a novel varia...
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An image coder based on the singular value decomposition and vector quantization is presented. The singular values and singular vectors of image sub-blocks are computed at the encoder and quantized using a novel variable bit-rate coding scheme. The performance of the coder is assessed by computer simulations.
The identification of centers of clustering is of interest in many areas of applications. In this study, it is argued that stochastic geometry models are helpful both in providing models for clustering and as a prior ...
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The identification of centers of clustering is of interest in many areas of applications. In this study, it is argued that stochastic geometry models are helpful both in providing models for clustering and as a prior distribution to combat overestimation of the number of clusters and to improve robustness.
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