A description is given of a versatile imageprocessing system developed at Pratt & Whitney Aircraft (P&WA) and the highly efficient spatial domain filtering techniques which are its computational heart. By exp...
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A description is given of a versatile imageprocessing system developed at Pratt & Whitney Aircraft (P&WA) and the highly efficient spatial domain filtering techniques which are its computational heart. By exploiting block average filtering techniques requiring only local storage, each block filtering operation uses only four additions and one multiplication per pixel, regardless of image or block size. As a consequence, extremely rapid imageprocessing is possible; for example, deconvolution of a 512 multiplied by 512 pixel image can be performed in just five seconds on an IBM 3033 with Fortran code.
A general and computationally inexpensive algorithmic scheme is presented that falls in a region detection category. In the scheme, a minimal spanning tree is used as a path of a sequential region grower. The algorith...
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A general and computationally inexpensive algorithmic scheme is presented that falls in a region detection category. In the scheme, a minimal spanning tree is used as a path of a sequential region grower. The algorithm traverses the spatially adjacent graph while maintaining the structural organization of an image. The graph-theoretical evaluation of heuristics is described and examples of implementation are given.
image data compression can be achieved by a number of techniques such as DPCM and Transform Coding. Adaptive image compression can be done with any of these techniques. Adaptive image data compression is a procedure i...
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image data compression can be achieved by a number of techniques such as DPCM and Transform Coding. Adaptive image compression can be done with any of these techniques. Adaptive image data compression is a procedure in which the number of bits allocated to each image block changes from block to block depending on the block complexity. This variable input bit rate must be converted to a constant output bit rate by a rate buffer. A study is made of some causal and noncausal approaches to adaptively allocating bits under the constraint of a fixed size buffer. A discussion is also presented of the optimal noncausal approach whose performance is a least upper bound on any causal approach.
The three-dimensional shape analysis problem is a very demanding test of shape analysis algorithms. Previous approaches to the problem have employed global features such as moments and Fourier descriptors. Global feat...
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The three-dimensional shape analysis problem is a very demanding test of shape analysis algorithms. Previous approaches to the problem have employed global features such as moments and Fourier descriptors. Global features lack the capacity for solving the partial shape recognition problem, in which only part of the unknown shape is available. Previous approaches to local shape analysis have employed structural (syntactic) methods, but these methods have so far failed to solve the three-dimensional problem. This study describes a hybrid structural/statistical local shape analysis algorithm which is applied to the three-dimensional problem.
recognition of three dimensional objects independent of size, position and orientation is an important and difficult problem of scene analysis. The use of three dimensional moment invariants is proposed as a solution....
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recognition of three dimensional objects independent of size, position and orientation is an important and difficult problem of scene analysis. The use of three dimensional moment invariants is proposed as a solution. The generalization of the results of two dimensional moment invariants which had linked two dimensional moment invariants to binary quantics is done by linking three dimensional moments to ternary quantics. The existence and number of n**t**h order moments in two and three dimensions is explored. Algebraic invariants of several ternary forms under different orthogonal transformations are derived by using the invariant property of the coefficients of ternary forms. The result is a set of three dimensional moment invariants which are invariant under size, orientation and position change.
In dynamic radiological studies time-dependent processes, ranging from motion of the patient's own anatomical structures to the kinetics of a contrast agent or radiotracer, are recorded in a sequence of image fram...
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In dynamic radiological studies time-dependent processes, ranging from motion of the patient's own anatomical structures to the kinetics of a contrast agent or radiotracer, are recorded in a sequence of image frames. If the data are available in digital format, appreciation of regional patterns of behavior can be enhanced by digital operations on the image sequence. These operations can be considered as projecting out aspects of temporal behavior that are not readily or unambiguously perceptible to the unassisted observer. A report is presented on experiences with such functional images in three radiological modalities at the University of Wisconsin. Examples include nuclear medicine studies of the heart and liver, transmission computed tomography studies of the brain, and digital fluoroscopic studies of the heart and kidneys.
A segmentation method for pap smear images is proposed to locate cellular boundary based on the stability of cellular boundary, and to locate nucleus based on the threshold deciding from the modified histogram. It emp...
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A segmentation method for pap smear images is proposed to locate cellular boundary based on the stability of cellular boundary, and to locate nucleus based on the threshold deciding from the modified histogram. It emphasizes the selection of the thresholds for nuclear and cytoplasmic boundary tracking. The authors also look into the problem of touching cells by using shape information of cellular boundary and texture information in the touching area. The proposed method, as applied to 11 scenes which contain 19 cells of different classes, works satisfactorily without any human interactions.
The problem of automatic registration of deformed images is addressed. It describes an iterative technique for gradually updating the local registration of two images based on a dynamic cooperative model. the method i...
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The problem of automatic registration of deformed images is addressed. It describes an iterative technique for gradually updating the local registration of two images based on a dynamic cooperative model. the method is cooperative in the sense that a feature at one location in an image influences decisions made at other locations. Initially, when registration is expected to be poor and feature measures unreliable, cooperative interaction is strong. It is progressively weakened with each iteration to permit matching of fine details. For a physical analogy, consider an elastic picture whose stiffness decreases with each iteration, and which is deformed by forces arising from similar features in another picture. Examples are shown for both dot patterns and gray-scale pictures.
An algorithm for finding the medial axis of an object in a 2-D binary picture has been developed. A set of real-valued boundary points for the object is extracted and smoothed using a linear combination of points in t...
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An algorithm for finding the medial axis of an object in a 2-D binary picture has been developed. A set of real-valued boundary points for the object is extracted and smoothed using a linear combination of points in the immediate neighborhood. A more detailed set of points is then defined by interpolation using a parabolic blending technique. To obtain the medial axis, circles are fitted for each point in the detailed set of points. Ech circle must be tangent to the point, be totally enclosed by the object and be of maximum size. The centers of these circles lie on the medial axis. The technique is especially suited to noisy data or coarsely sampled shapes.
Sequences of pictures of growing colonies of animal cells or microorganisms contain information useful to biologists. Special lighting increases the information contained in the pictures and decreases the difficulty o...
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Sequences of pictures of growing colonies of animal cells or microorganisms contain information useful to biologists. Special lighting increases the information contained in the pictures and decreases the difficulty of the image analysis. A high resolution flying spot scanner digitizes images of petri dishes recorded on film. Nonlinear edge region detectors and a region growing algorithm find the outlines of the colonies. Outlines which pass tests for validity are analyzed to extract further information. Data files of parameters are created which are analyzed by programs written by biologists. Statistical and other techniques were used to classify species and locate mutant colonies.
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