An algorithm for labeling image regions based on pixel-level statistical pattern recognition is presented. The structure of multiscale regions about each pixel is measured by means of isotropic Gaussian filters and by...
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ISBN:
(纸本)0818620390
An algorithm for labeling image regions based on pixel-level statistical pattern recognition is presented. The structure of multiscale regions about each pixel is measured by means of isotropic Gaussian filters and by a multiscale orientation field. A redundant feature space representing several aspects of image structure across scale, orientation, and space is created. The segmentation algorithm decides membership of pixels in regions by means of simple statistical pattern recognition methods, such as distance measurement and thresholding. Feature vectors are examined locally to determine region membership;the features incorporate multiscale image structure information. Results of multiscale image segmentations on biomedical images are presented.
A cepstrum technique that not only is capable of precise registration of fundus images but also leads to three-dimensional reconstruction of fundus structures with a motion stereo model is presented. The use of cepstr...
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ISBN:
(纸本)0818620390
A cepstrum technique that not only is capable of precise registration of fundus images but also leads to three-dimensional reconstruction of fundus structures with a motion stereo model is presented. The use of cepstrum techniques allows the representation of the three-dimensional features in a quantitative manner that is impossible to obtain from just a stereoscopic view. A geometrical transformation using a set of polynomial functions is introduced. The definition of the two-dimensional power cepstrum and the analytical procedure for obtaining the disparity are shown in detail. A modified time-sequenced stereo model using a matching technique, i.e., the two-dimensional cepstrum, is introduced.
Several methodologies and tools for enhancing the clinician's ability to visualize and characterize perfusion defects are presented. The tools include an improved method for sampling the myocardium which reduces t...
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ISBN:
(纸本)0818620390
Several methodologies and tools for enhancing the clinician's ability to visualize and characterize perfusion defects are presented. The tools include an improved method for sampling the myocardium which reduces the partial volume effects often encountered when sampling the apex, volume-weighted and distance-weighted polar maps that enhance the information extracted from the new sampling technique, a method for visualizing perfusion information in three dimensions which decreases the distortions inherent in 2-D polar maps and also allows for unifying the perfusion information with the anatomic information obtained from 3-D coronary trees, and a method for visualizing 3-D gated perfusion information that allows a clinician to assess both perfusion and wall thickening.
To assess the feasibility of computer-aided surgery (CAS) with three-dimensional (3-D) graphic reconstruction, the authors describe an experiment in which direct needle punctures were made into porcine liver phantoms ...
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ISBN:
(纸本)0818620390
To assess the feasibility of computer-aided surgery (CAS) with three-dimensional (3-D) graphic reconstruction, the authors describe an experiment in which direct needle punctures were made into porcine liver phantoms on the basis of a collision assessment. A 90% success rate was achieved when a generalized cylinder method for vessel reconstruction was used. A clinical trial of this system for surgical planning shows its potential for use in abdominal surgery.
An approach to creating a three-dimensional computer model of an arterial structure based on magnetic resonance (MR) images from a limited number of views is described. The computer model assumes that the vascular str...
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ISBN:
(纸本)0818620390
An approach to creating a three-dimensional computer model of an arterial structure based on magnetic resonance (MR) images from a limited number of views is described. The computer model assumes that the vascular structure is composed of connected conical segments. From this three-dimensional computer model, quantitative measurements of vessel diameter, length, and position are available for any subset of the arterial structure. visualization is enhanced by displaying the computer model rather than a direct set of images obtained from different perspectives. Ambiguities from overlapping branches can be resolved by rotating the model or by eliminating the interfering structures. The application of the approach to a glass phantom of an abdominal aorta is described, along with a three-dimensional computer model created by reconstructing the geometry extracted from two MR scans of the phantom.
A mechanical model for studying tissue morphogenesis by directed cell neighbor change is proposed. The model describes cell rearrangements by accounting for the balance of forces between neighboring cells that are fun...
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ISBN:
(纸本)0818620390
A mechanical model for studying tissue morphogenesis by directed cell neighbor change is proposed. The model describes cell rearrangements by accounting for the balance of forces between neighboring cells that are functionally coupled. It allows for the testing of assumptions and theories in a precise and rigorous manner incorporating known biological and physical principles. The model is applied to two embryological processes: epiboly in the killyfish Fundulus and notochord extension in the frog Xenopus. It is noted that changing model parameters, such as the boundary conditions of the mechanical properties of a motile or adhesive cell subpopulation, allows the model to be applied in a wide range of settings in developmental and cell biology. It can be used as a testbed for investigating the mechanical conditions underlying normal embryonic development and for investigating the cellular mechanical properties responsible for developmental abnormalities.
A comprehensive software package, called ANALYZE, which permits detailed investigation and evaluation of 3-D and 4-D biomedical images is described. This software can be used with any 3-D imaging modality, including X...
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ISBN:
(纸本)0818620390
A comprehensive software package, called ANALYZE, which permits detailed investigation and evaluation of 3-D and 4-D biomedical images is described. This software can be used with any 3-D imaging modality, including X-ray computed tomography, radionuclide emission tomography, ultrasound tomography, magnetic resonance imaging, and both light and electron microscopy. The package is powerful in its synergistic integration of fully interactive modules for direct display, manipulation, and measurement of multidimensional image data. Several original algorithms that improve image display efficiency and quality are included. One of these is a versatile and powerful volume rendering algorithm. The inclusion of a variety of editing, quantitative mensuration, and macro design tools significantly extends the usefulness of the software., ANALYZE runs on standard Unix computers without special-purpose hardware.
An approach for reconstructing the three-dimensional geometry of the coronary arteries from a limited number of two-dimensional angiographic views and producing a computer model which can be used to quantify and visua...
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ISBN:
(纸本)0818620390
An approach for reconstructing the three-dimensional geometry of the coronary arteries from a limited number of two-dimensional angiographic views and producing a computer model which can be used to quantify and visualize the coronary vasculature is presented. The approach incorporates a hierarchical database that organizes geometric information from arbitrary arterial structures in a natural fashion. Detecting and locating vascular structure from angiogaphic images are partially automated through entropy edge detection techniques. The back projection algorithm accurately models the nonparallel geometry inherent in X-ray biplane angiography and produces a quantitative description of vascular structure, including estimates of vessel diameters and lengths. The approach has been applied in phantom studies, in which quantitative comparisons were made, and patient studies, in which qualitative evaluations were made.
The authors describe a knowledge-based system for detecting the interior and exterior boundaries of the left ventricle (LV) from time-varying cross-sectional images of the beating heart obtained noninvasively by magne...
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ISBN:
(纸本)0818620390
The authors describe a knowledge-based system for detecting the interior and exterior boundaries of the left ventricle (LV) from time-varying cross-sectional images of the beating heart obtained noninvasively by magnetic resonance imaging (MRI). The system automatically classifies and measures cardiac function through estimates of LV wall thickness, wall motion, etc. The system is knowledge based and it makes use of Dempster-Shafer theory to manage the knowledge. This theory is also used to control the flow of system information for more efficient use of limited computational resources and memory space.
A set of programs developed to display the potentials and the magnitudes of the estimated potential gradients generated by defibrillation shocks are discussed. There are three types of displays. The first type display...
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ISBN:
(纸本)0818620390
A set of programs developed to display the potentials and the magnitudes of the estimated potential gradients generated by defibrillation shocks are discussed. There are three types of displays. The first type displays three-dimensional surfaces constructed from electrode locations. Potentials or gradient magnitudes are interpolated over each surface and are displayed as spatial changes in intensity or hue. The second type of display is a three-dimensional surface reconstruction of the heart and electrodes. This display is used to verify the three-dimensional electrode coordinates that are obtained from digitized images of the heart. The third type of display is a volume reconstruction of the myocardium. In this display, spatial changes in potentials or gradient magnitudes in the myocardial volume are represented by spatially varying the hues of the volume elements. The electrical values of most volume elements are interpolated by means of a three-dimensional method based on discrete smooth interpolation.
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