An environment for guided image interpretation in neuroanatomy is described. The authors describe a hyperdocument, created for the user, which allows for browsing and following guided tours through brain sections/volu...
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ISBN:
(纸本)0818620390
An environment for guided image interpretation in neuroanatomy is described. The authors describe a hyperdocument, created for the user, which allows for browsing and following guided tours through brain sections/volumes and the associated visual knowledge base, and an externalized cognitive map (XCM), created for the machine, which incorporates a volumetric atlas. The proposed environment integrates the hyperdocument representation with text and figure, the 3-D volumetric atlas, volume and surface visualization, and an interactive user interface. The environment serves as an integrating framework to facilitate visual understanding, inference, retrieval, and comparison of all relevant information, both structural and functional.
Jet spatial resolution as visualized by color Doppler flow mapping has previously been shown to be affected by physical factors, such as driving pressure, and technical factors, such as instrument settings. An additio...
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ISBN:
(纸本)0818620390
Jet spatial resolution as visualized by color Doppler flow mapping has previously been shown to be affected by physical factors, such as driving pressure, and technical factors, such as instrument settings. An additional factor producing superimposed variability, namely, the interaction of the jet with solid boundaries in the distal receiving chamber, is illustrated. The broader point that jet velocities (i.e., Doppler images) do not uniquely represent jet volume is demonstrated.
A PC-based imaging system designed for the three-dimensional display and analysis of biomedical image information is described. Hardware considerations emphasizing minimal requirements for providing an acceptable perf...
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ISBN:
(纸本)0818620390
A PC-based imaging system designed for the three-dimensional display and analysis of biomedical image information is described. Hardware considerations emphasizing minimal requirements for providing an acceptable performance are outlined. The approach implemented in the system consists of segmentation and interpolation, surface tracking, and creation of rendered images. Most of the operations are implemented without floating-point computations. A smooth and consistent user interface makes the system easy to use in a biomedical imaging environment. The throughput of the system is satisfactory: a typical study can be completed in about 30 minutes from start to finish.
The use of qualitative models as opposed to quantitative models for object recognition and reconstruction is discussed. Central to the authors' model is an attempt to identify a minimal subset of attributes releva...
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ISBN:
(纸本)0818620390
The use of qualitative models as opposed to quantitative models for object recognition and reconstruction is discussed. Central to the authors' model is an attempt to identify a minimal subset of attributes relevant to visualization. Each object is decomposed into simpler components, with each component described as a qualitative generalized cylinder and the joining operations specified by a three-dimensional qualitative spatial reasoning scheme. The spatial reasoning used is systematically derived and provides a complete description under considerations of tangency, nocontact, and overlap. The representation must be compact, yet contain sufficient information to be 'recognizable'--a term that is defined in terms of human perception and constitutes a measure of the goodness of the model.
A method for 3-D surface mapping from computed tomography (CT) images of the abdomen is described. The liver can be visualized in 3-D from any perspective and can be shown either alone or through the translucent abdom...
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ISBN:
(纸本)0818620390
A method for 3-D surface mapping from computed tomography (CT) images of the abdomen is described. The liver can be visualized in 3-D from any perspective and can be shown either alone or through the translucent abdominal wall. Artificial-intelligence techniques are used to identify salient anatomic features from which the lobar and segmental anatomy can be determined. These methods are applied to abdominal CTs of potential donors of segmental liver transplants, in which preoperative volumetry and visualization of the left lateral segment are of significant value.
The role and importance of critical parameters, such as cardiac output, ventricular pressure, and papillary muscle position, on mitral valve behavior and on the development of the ventricular flow field are studied. S...
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ISBN:
(纸本)0818620390
The role and importance of critical parameters, such as cardiac output, ventricular pressure, and papillary muscle position, on mitral valve behavior and on the development of the ventricular flow field are studied. Steady and pulsatile flow visualization experiments demonstrate that the main factor which affects the ventricular function is the papillary muscle position. By controlling regurgitation, it can change the cardiac output, as well as the ventricular pressure. A qualitative agreement is found between a color Doppler ultrasound flow field and those obtained by flow visualization.
The authors describe a method for the automatic identification of labeled neuronal cell populations, coupled with the subsequent three-dimensional reconstruction and volumetric rendering of a set of serial thin sectio...
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ISBN:
(纸本)0818620390
The authors describe a method for the automatic identification of labeled neuronal cell populations, coupled with the subsequent three-dimensional reconstruction and volumetric rendering of a set of serial thin sections. This was achieved by applying morphological image-processing operations to each of the serial sections. Surface fitting techniques were then developed for the neuronal cell population delineation. The coupling of volumetric rendering and interior surface fitting adds to the ease of visual interpretation of this complicated three-dimensional structure.
The authors describe two ray-tracing algorithms for deriving an optical point-spread function (PSF) from corneal topography measurements: one a simple adaptation of the lensmaker's equations, the other a classical...
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ISBN:
(纸本)0818620390
The authors describe two ray-tracing algorithms for deriving an optical point-spread function (PSF) from corneal topography measurements: one a simple adaptation of the lensmaker's equations, the other a classical geometric refraction. The relative efficiency of the two algorithms is objectively evaluated in terms of actual compute time. The overall difference in the resulting PSFs is characterized by means several statistical measures, and subjective evidence of the accuracy of modeling visual effects is presented.
Preliminary results concerning the feasibility of using nuclear magnetic resonance (NMR) imaging techniques to visualize 3-D time-dependent flow fields are presented. The possibility of clinical application of this te...
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ISBN:
(纸本)0818620390
Preliminary results concerning the feasibility of using nuclear magnetic resonance (NMR) imaging techniques to visualize 3-D time-dependent flow fields are presented. The possibility of clinical application of this technique is evaluated by measuring steady flow in straight circular tubes, converging sections, and downstream of prosthetic aortic valves, as well as pulsatile flow in circular tubes. Measurements by NMR are compared with previously published results and theoretical data using different visualization techniques. The strategies and techniques used to display the flow images optimally are presented. Preliminary results on the accuracy of flow images obtained from NMR data are presented.
Algorithms for high-speed visualization and manipulation of high-resolution medical objects are described. Central to these algorithms is a novel method of object representation, called a semiboundary, which stores bo...
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ISBN:
(纸本)0818620390
Algorithms for high-speed visualization and manipulation of high-resolution medical objects are described. Central to these algorithms is a novel method of object representation, called a semiboundary, which stores boundary voxels of the object as a row-indexed list, along with a code associated with each voxel that indicates which of its neighbors are outside the object and which are inside. The algorithms for manipulation take as input a semiboundary and produce either a depiction or a new semiboundary of the altered object. Rendering speeds obtainable only on systems with specialized hardware design have been achieved on general-purpose workstations entirely through optimum algorithms. The potential use of the methodology in surgical planning is illustrated.
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