Abstract: A method for approximating X-ray detector data from malfunctioning computed tomography detectors. A view of data is gathered for each of a plurality of detectors in a stationary detector scanner. Data for each malfunctioning detectors is approximated by interpolating data from detectors closely positioned with respect to the malfunctioning detectors after regions of high contrast within a cross-section of interest have been identified.
Abstract: A computer tomography system has an X-ray source and a radiation receiver having an array of individual detectors each forming an electrical signal corresponding to the received radiation intensity, the X-ray source being rotated about a subject for transradiating a layer of the subject from different directions, and a measured value processing circuit to which the output signals of the individual detectors are supplied and which identifies therefrom attenuation values of predetermined points in the transradiated plane of the subject for generating a display image. The measure value processing circuit has a convolution computer, and further has an adaptive digital filter and a filter control unit to which the signals from the array are supplied before being operating on by the convolution computer. The filter control unit controls the transfer function of the filter as a function of the filter input signal so as to substantially reduce image artifacts due to quantum and electronics noise.
Abstract: Morphemic, conceptional or semantic, and syntaxic dictionaries (21-23) keep morphemic, conceptional, and syntaxic items, respectively. Each morphemic item comprises a morphemic description and a first pointer pointing to a set of syntaxic items corresponding to the morphemic description. Similarly, each conceptional item comprises a conceptional description or symbol and a second pointer pointing to a set of syntaxic items. Each syntaxic item comprises a syntaxic description and a third and a fourth pointer pointing to a set of morphemic items and to a set of conceptional items, respectively. Responsive to an input expression, a retrieving arrangement (24) retrieves a morphemic and a conceptional item when the input expression is morphemic and conceptional, respectively. The first or the second pointer of the retrieved item is used in retrieving a syntaxic item by which the morphemic and/or the conceptional dictionary is referred back to.
Abstract: A preferred embodiment of a method for developing a single set of time intervals for controlling a memory device effectively utilizes a histograph having two parallel time lines with the same scale. One time line has a series of minimum time periods, each corresponding to when a respective event might occur. The other time line has a series of maximum time periods during which the respective events might occur. Time segments are defined between corresponding minimum and maximum time periods and sample rates and ratios are assigned to each time segment. At each start and end time of a period, the possible sample rates needed at that time are compared and the fastest sample rate is selected. The ratios are similarly analyzed, and the minimum ratio is selected. Consecutively occurring sample rates having the sample value are grouped into respective time intervals.
January 14, 1985
Date of Patent:
August 25, 1987
Vincent P. Zeller, Wesley J. Burris, II
Abstract: In a method and device for the study of surface layers and subjacent layers of interest, the device comprises receivers and at least two transmission sources spaced at a distance such that a set of traces produced by one of the transmission sources does not interfere with a set of traces produced by the other transmission source when the two sets of traces are on the same time-section.
March 20, 1984
Date of Patent:
January 13, 1987
Societe Nationale Elf Aquitaine (Production), Compagnie Generale de Geophysique
Serge Vannier, Robert Garotta, Andre Lozes, Jean C. Vidal