A projection of a picture may be defined as a set of values, each of which is then sum of the gray levels along a known ray path through the picture. Reconstruction is achieved by operating on a set of projections to ...
详细信息
A projection of a picture may be defined as a set of values, each of which is then sum of the gray levels along a known ray path through the picture. Reconstruction is achieved by operating on a set of projections to produce approximations to the original picture. In general, there are many pictures with the same projection set. Factors contributing to and causing this ambiguity are examined. The reconstruction problem arises in X-ray analysis and electron microscopy of translucent objects, such as ribosomes. Given a projection set, it is desirable to determine what the original image looked like, both for further study and to be able to compute new projections at new angles without taking new x-rays or micrographs. Projections are also considered as a form of data compression in patternrecognition, where they may be used as a form of feature extraction.
image segmentation is that part of image analysis that concerns itself with the spatial definition of the various ″objects″ constituting a visual scene. This paper presents a case for combining the line, region and ...
详细信息
image segmentation is that part of image analysis that concerns itself with the spatial definition of the various ″objects″ constituting a visual scene. This paper presents a case for combining the line, region and semantic structure of a general class of images in the pursuit of meaningful segmentation. It is proposed that fragmentary line extracts and region pieces might interact in refining each in a structured way with the semantic component entering both at the low level of defining the acceptable linkage processes for combination of line and region fragments and also at the high level of human interpretation of the results and interactive feedback aimed at improving the computational processes invoked. Preliminary implementation results are given for a number of simple image scenes.
Despite the numerous linguistic and syntactic procedures proposed for scene analysis, the features in terms of which a real scene can be modelled have not been defined in a comprehensive manner. In the processing of t...
详细信息
Despite the numerous linguistic and syntactic procedures proposed for scene analysis, the features in terms of which a real scene can be modelled have not been defined in a comprehensive manner. In the processing of the image of a real scene a profusion of features are obtained. A large percentage of these are extraneous while some critical ones used in the linguistic description will be missing. To find a predefined combination of features from such a collection, even on a probabilistic basis, results in a combinatorial explosion. Yet, in the literature on psychology of vision, on the effects of brain damage, on how to draw pictures, etc. , there is a wealth of hints on how ″biological systems″ appear to solve the scene analysis problem. To biological systems, scene analysis ″comes naturally″;one is not even aware that the problem exists. Some observational results will be compared with computational procedures.
The major problem encountered in scene analysis is that the picture patterns to be examined are always subject to changes in translation, scale, contrast or more generally to so-called ″rubber sheet″ distortions. Th...
详细信息
The major problem encountered in scene analysis is that the picture patterns to be examined are always subject to changes in translation, scale, contrast or more generally to so-called ″rubber sheet″ distortions. Then any scene analysis system using the models that represent and match a picture pattern in the actual image in terms of a fixed template will be infeasible in actual applications. A reasonable solution to the failure of the fixed template model is suggested. A model in the form of a flexible template, in which information concerning the variations that actual visual objects are allowed to have are included in the representation, is used to represent and match the picture patterns. To do this, the template is parameterized in such a way that it will not be sensitive, or even variant, to any of the rubber-sheet distortions. Then by assigning a cost function which corresponds to the way that the set of parameters might be adjusted, a decision scheme is used to evaluate the cost and render the set of optimum parameters that constitute the visual object.
A new edge strength evaluation and detection technique for picture analysis is reported. This technique was developed to upgrade performance of the region grower (object locator), based on edge detection. The main mot...
详细信息
A new edge strength evaluation and detection technique for picture analysis is reported. This technique was developed to upgrade performance of the region grower (object locator), based on edge detection. The main motive behind the development of the new edge operation was performance ungrading along the following lines: (1) efficient detection of points that are obviously not edge points;(2) achievement of independence of the edge value from shape and structure of the objects (lines, sharp corners, etc. );(3) keep the edge evaluation self scaling with respect to linear changes in signal and noise. To achieve those seemingly conflicting goals, a sequential decision approach was used.
Digital imageprocessing has been extended to the enhancement of time-varying picture information. Fluoroscopic medical images recorded on videotape have been processed by digital filtering to enhance cardiac synchron...
详细信息
Digital imageprocessing has been extended to the enhancement of time-varying picture information. Fluoroscopic medical images recorded on videotape have been processed by digital filtering to enhance cardiac synchronous densitometry related to the pulsatile perfusion of blood in lung tissue. The enhancement was obtained by means of a Wiener filter adapted to the power spectrum of the electrocardiogram which is recorded on the audio channel of the videotape. Since the enhancement is of temporal contrast variations as opposed to spatial ones, the resulting information contains valuable physiological data. The authors' experiments have indicated that pulmonary vascular pulsations are diminished in amplitude in human patients with lung carcinoma. These pulsations are not visible to the radiologist without the computer enhancement. The changes in the densiometer signal from vascular pulsations are typically on the order of 0. 5%.
An interactive graphics system with bi-directional audio capability has been developed for use in classifying and describing (or characterizing) speech and image data. The use of an interactive system allows human ins...
详细信息
An interactive graphics system with bi-directional audio capability has been developed for use in classifying and describing (or characterizing) speech and image data. The use of an interactive system allows human inspection of intermediate steps in algorithm development, easy modification of parameters, and immediate examination of the results. The graphics portion of the system uses a keyboard, joystick, opaque and transparent image scanners, and control panel for data input and has access to a Tektronix 611 memory scope, an electrostatic printer/plotter, a Calcomp plotter, and a high-resolution CRT with a camera attachment for data output. As many as three different files may be processed concurrently and may be stored either on magnetic tape or disc. A history file which maintains a record of all or selected operations, may be viewed directly or on hardcopy. The system has been used to generate a labelled speech data base of 35,000 tokens for use in semi-automatic speaker identification character recognition algorithm capable of MOS/LSI realization, to analyze imagery for bandwidth reduction studies, and to research classification and matching algorithms for use in fingerprint processing. Examples from each of the application areas are presented.
暂无评论