It is noted that a necessary requirement of a strategic defense system is the detection of incoming nuclear warheads in an environment that may include nuclear detonations of undetected or missed target warheads. A co...
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It is noted that a necessary requirement of a strategic defense system is the detection of incoming nuclear warheads in an environment that may include nuclear detonations of undetected or missed target warheads. A computer model is described which simulates incoming warheads as distant endoatmospheric targets. A model of the expected electromagnetic noise present in the nuclear environment is developed; predicted atmospheric effects are included. Various morphological-based image-enhancement algorithms are examined with regard to their ability to suppress the noise and atmospheric effects of the nuclear environment. These algorithms are then tested, using the combined target and noise models, and evaluated in terms of noise removal and the ability to resolve closely spaced targets.< >
Cardiac function is often evaluated quantitatively using two-dimensional echocardiography to analyze shape attributes, such as the heart wall thickness or the shape change of the heart wall boundaries. A review of pre...
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Cardiac function is often evaluated quantitatively using two-dimensional echocardiography to analyze shape attributes, such as the heart wall thickness or the shape change of the heart wall boundaries. A review of previous work in detecting the heart wall boundaries is presented, along with how this problem can be viewed from a computervision perspective. The principles of echo image sequence analysis and high-level analysis are described. It is suggested that one promising approach is to use multiple-resolution processing by using a large window smoothed image for the initial detection of major edge segments, followed by smaller and smaller windows until a complete boundary is found.< >
One approach to image coding is to segment the original gray-scale image and then encode the boundaries and the interiors of the segments to represent the image. The authors propose a novel image coding method based o...
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One approach to image coding is to segment the original gray-scale image and then encode the boundaries and the interiors of the segments to represent the image. The authors propose a novel image coding method based on this approach, with an important difference. With the proposed coding technique, an alternative representation of the image segments is used; instead of segment boundaries, morphological skeletons are used to represent the segments. The skeleton is a thin-lined caricature of the segment that summarizes its shape and conveys information about its size, orientation, and connectivity. A binary image morphological skeletonization procedure is used to create skeletons of the image segments. In this way, the gray-scale image is represented for coding purposes by the skeletons and the intensities of the segments. Preliminary estimates show a data rate of 0.12 bits per pixel can be obtained with this coding technique.< >
This paper discusses the relationship between the zero crossings or zeros of band-limited signals and their nonlinear transformations. It is proved that the bandwidth of a signal can be compressed by a ratio of 1/ n i...
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This paper discusses the relationship between the zero crossings or zeros of band-limited signals and their nonlinear transformations. It is proved that the bandwidth of a signal can be compressed by a ratio of 1/ n if and only if the signal has n th-order zero crossings or zeros (if complex). Also, a monotonic nonlinearity in the observation of a band-limited signal can be identified from the zero crossings (or zeros) of the derivative of the observed signal. (The results are for one-dimensional signals. Extensions to two-dimensional signals remain to be addressed.)
There are several methods available for representing boundaries in two dimensions. The more widely known ones involve boundary modeling with run-length codes, chain codes and polygons, AR model coefficients, Fourier d...
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There are several methods available for representing boundaries in two dimensions. The more widely known ones involve boundary modeling with run-length codes, chain codes and polygons, AR model coefficients, Fourier descriptors (FD's) and B-spline control points (CP's). In this paper, we present results showing the usefulness of CP's in boundary representation. CP's can yield large compression of the boundary data and they exercise local control over boundary shape. Because they can be normalized with respect to scale, translation and rotation, they are valuable in boundary matching applications. Finally, being the series coefficients of spline basis functions, CP's are useful features for boundaries detected in noisy environments.
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