The Karhunen-Loeve transform (KLT) is applied to the analysis of dynamic sequences of thermograms describing the temporal evolution of body surface temperature following the application of an external thermal stimulus...
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ISBN:
(纸本)0818608625
The Karhunen-Loeve transform (KLT) is applied to the analysis of dynamic sequences of thermograms describing the temporal evolution of body surface temperature following the application of an external thermal stimulus. The KLT may be evaluated either along the spatial or temporal dimensions of the data;the duality of both representations is emphasized. An example is presented to illustrate that the KLT allows an efficient data reduction and facilitates tumor detection by highlighting physiologically important abnormalities in the time behavior of thermal patterns.
The author studies an application of the rapid transform for classification of entire two-dimensional shapes. The algorithm is based on the transform invariance property under cyclic shifts. A boundary will be represe...
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ISBN:
(纸本)0818608625
The author studies an application of the rapid transform for classification of entire two-dimensional shapes. The algorithm is based on the transform invariance property under cyclic shifts. A boundary will be represented by a sequence of segments defining the feature vector components of the shape. It is assumed that a sequence of segments corresponding to a rotated pattern, can be deduced from an original sequence of the same pattern by a number of cyclic shifts. Then, the transform of the vector of segments is independent of translation and rotation of the pattern in two dimensions. The classification algorithm will be tested on data derived from a library of two-dimensional aircraft patterns. The results show the algorithm efficiency in terms of computation time and classification.
A description is given of the development of a model-based vision system that utilizes hierarchies of both object structure and object scale. The focus of the research is to use these hierarchies to achieve robust rec...
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ISBN:
(纸本)0818608625
A description is given of the development of a model-based vision system that utilizes hierarchies of both object structure and object scale. The focus of the research is to use these hierarchies to achieve robust recognition based on effective organization and indexing schemes for model libraries. The goal of the system is to recognize parameterized instances of nonrigid model objects contained in a large knowledge base, despite the presence of noise and occlusion. Robustness is achieved by developing a system that can recognize viewed objects that are scaled or mirror-image instances of the known models or that contain component subparts with different relative scaling, rotation, or translation than in the models. The approach taken in this thesis is to develop an object shape representation that incorporates a component subpart hierarchy, to allow for efficient and correct indexing into an automatically generated model library as well as for relative parametrization among subparts, and a scale hierarchy, to allow for a general to specific recognition procedure. The implemented system uses a representation based on significant contour curvature changes and a recognition engine based on geometric constraints of feature properties. Examples of the system's performance are given, followed by an analysis of the results.
A novel method is presented for grouping range image regions such that each group of regions represents a meaningful part of an object. The set of regions, defined as a convex region set (CRS), is obtained by analyzin...
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ISBN:
(纸本)0818608625
A novel method is presented for grouping range image regions such that each group of regions represents a meaningful part of an object. The set of regions, defined as a convex region set (CRS), is obtained by analyzing the boundary types between a pair of regions. The boundary types are classified as convex, concave, and jump boundaries. If two regions share a convex boundary it is assumed that they are inseparable regions, thus describing the same part (object). The CRSs are determined by a region boundary graph (RBG) which is defined as a graph whose nodes represent regions, and the edges represent boundaries: convex and concave. Since jump boundaries represent no physical contact in 3-D, they are represented as null edges. A CRS is defined as set of regions (or nodes in an RBG) such that for each pair of regions in the set, there is a path, which is represented only by convex edges. The physical interpretation is that a CRS represents part of an object such that the regions in the set can not be separated.
Algorithms are developed to recover the depth and orientation maps of a surface from its image intensities. They combine the advantages of stereo vision and shape-from-shading (SFS) methods. These algorithms generate ...
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ISBN:
(纸本)0818608625
Algorithms are developed to recover the depth and orientation maps of a surface from its image intensities. They combine the advantages of stereo vision and shape-from-shading (SFS) methods. These algorithms generate dense surface depth and orientation maps accurately and unambiguously. Previous SFS algorithms can not be directly extended to combine stereo images because the recovery of surface depth and that of orientation are separated in these formulations. A novel SFS algorithm is proposed to couple the generation of the depth and orientation maps. The formulation also ensures that the reconstructed surface depth and its orientation are consistent. The SFS algorithm for a single image is next extended to utilize stereo images. The correspondence over stereo images is established simultaneously with the generation of surface depth and orientation. An alternative approach is also suggested from combining stereo and SFS techniques. The use of embedding techniques to combine sparse depth measurements is discussed.
The authors present the design of 'zoom and pan' (ZaP), a complex 160K-transistor delay-insensitive VLSI circuit. ZaP generates images from structured geometric data with a performance of a million boxes per s...
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ISBN:
(纸本)0818608722
The authors present the design of 'zoom and pan' (ZaP), a complex 160K-transistor delay-insensitive VLSI circuit. ZaP generates images from structured geometric data with a performance of a million boxes per second. A VLSI program is derived from a formal specification of ZaP through stepwise refinement and decomposition. The subsequent silicon compilation is described briefly. It is concluded that ZaP demonstrates that the design of 'systems on silicon' can be seen as a VLSI-programming activity, to be carried out by system designers.
A descriptive classifier has been developed for silhouetted pictorial patterns. It has the capability of recognition with inherently high discriminatory power between an essentially unlimited number of discrete patter...
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ISBN:
(纸本)0818608625
A descriptive classifier has been developed for silhouetted pictorial patterns. It has the capability of recognition with inherently high discriminatory power between an essentially unlimited number of discrete pattern classes. The user is allowed substantial latitude in determining what pictorial instances of objects should be admitted to the same pattern category with pattern-class constraints that can be adjusted in an iterative fashion. The user can also generate and display random instances of a pictorial pattern class until, according to subjective evaluation, the pattern class defined within the machine is the same as that envisioned by the user. Pictorial classification is performed using a system-generated figure classification number. The figure classification number defines a unique point within a classification space having an assigned pattern-class name. The pattern class can, by user selection, be made to include many or few unique figure classification states. The system's performance is illustrated by the classification of a series of pictorial silhouettes.
The problem of finding a transformation that aligns a 3-D model with a 2-D image, using minimal amount of information, is discussed. Only the geometrical-alignment transformation is considered. This transformation is ...
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ISBN:
(纸本)0818608838
The problem of finding a transformation that aligns a 3-D model with a 2-D image, using minimal amount of information, is discussed. Only the geometrical-alignment transformation is considered. This transformation is composed of some transformation in 3-D space followed by a projection to the 2-D image plane. One of the main sources of the difficulty in object recognition is that under such transformations a single object can give rise to a wide range of different images. Knowledge of potential transformations from the stored model to the image can obviously facilitate the recognitionprocess and is necessary in localization.
The authors report on a model-based object recognition system and its parallel implementation on the Connection Machine system. The goal is to recognize two-dimensional objects in a scene, given a reasonably large dat...
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ISBN:
(纸本)0818608625
The authors report on a model-based object recognition system and its parallel implementation on the Connection Machine system. The goal is to recognize two-dimensional objects in a scene, given a reasonably large database of known objects. The system uses massively parallel hypothesis generation and parameter space clustering in place of serial constraint propagation. Local boundary features that constrain an object's position and orientation provide a basis for hypothesis generation. Parameter-space clustering of hypotheses is used to rank hypotheses according to preliminary evidence prior to verification. This greatly reduces the time for recognition and number of hypotheses that must be tested. Experiments show that the time required by this approach scales at a much slower rate than either the number of objects in the database or objects in the scene.
An approach to the dynamic scene analysis is presented which departs from previous work by emphasizing a qualitative strategy of reasoning and modeling. Instead of refining a single quantitative description of the obs...
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ISBN:
(纸本)0818608625
An approach to the dynamic scene analysis is presented which departs from previous work by emphasizing a qualitative strategy of reasoning and modeling. Instead of refining a single quantitative description of the observed environment over time, multiple qualitative interpretations are maintained simultaneously. This offers superior robustness and flexibility over traditional numerical techniques which are often ill-conditioned and noise-sensitive. The main tasks of the authors' approach are (a) to detect and to classify the motion of individual objects in the scene, (b) to estimate the robot's egomotion, and (c) to derive the 3-D structure of the stationary environment. These three tasks strongly depend on each other. First, the direction of heading (i.e., translation) and rotation of the robot are estimated with respect to stationary locations in the scene. The focus of expansion (FOE) is not determined as particular image location, but as a region of possible FOE-locations called the fuzzy FOE. From this information, a rule-based system constructs and maintains a qualitative scene model. Results of this approach for real and synthetic imagery are presented.
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