Abstract: An apparatus for correcting an X-ray tomographic image is presented, where the tomographic image is created by measuring an X-ray transmission coefficient at each of a plurality of X-ray beam paths through an object to enable reconstructing a tomographic image of the object. There is a device for selecting a plurality of volume averaged voxels along at least one of the X-ray beam ray paths, and for placing contiguous volume averaged voxels in a run length of volume averaged voxels, to make a plurality of run lengths of volume averaged voxels. There is a device for dividing the plurality of run lengths of volume averaged voxels into a plurality of subslices. There is a device, responsive to the plurality of subslices and responsive to the plurality of run lengths of volume averaged voxels, for computing a corrected value of X-ray attenuation coefficient for the X-ray beam ray path.

Abstract: Process for the reconstruction of three-dimensional images of an object (3), in which the reconstruction is obtained by calculating sums of projections on planes extracted from a conical attenuation radiation traversing the object, or an emission from the object in accordance with a conical collimation. The bidimensional detector array (4) used for this purpose has a random inclination (.xi.) with respect to the rotation axis defining the mark in which the image is reconstructed as a result of a voluntary choice. Formulas are given making it possible to obtain a limited distortion reconstruction after measuring the displacement parameters of the array and the conical radiation beam. The position errors resulting from construction defects are also taken into account in the calculations after measurement. A parameter measurement protocol and the associated calculation process are also described.

Abstract: A microtomographic system (10) for generating high-resolution, three dimensional images of a specimen (16) is disclosed. The microtomograph system includes an x-ray generator (12) that produces an x-ray beam (14), a specimen holder (18) that holds the specimen in the beam, and an x-ray detector (20) that measures the attenuation of the beam through the specimen. Two projections of each view of the specimen are made with this microtomographic system. Each projection is made with a different intensity x-ray beam. After the projections of one view of the specimen are made, the specimen is rotated on the specimen holder and another set of projections are made. The projections of each view of the specimen are analyzed together to provide a quantitative indication of the phase fraction of the material comprising the specimen. The projections of the different views are combined to provide a three-dimensional image of the specimen.

Abstract: A cone beam scanning apparatus reduces image artifacts incident to cone beam geometry by decomposing an acquired image into soft tissue and bone and air images based on the density of the pixels in that image. The soft tissue image is filtered to remove frequency space data corresponding to zones of incomplete frequency space data in the original projection image to remove the generated artifacts.

Abstract: A nuclear spectrometer employs asymmetrical weighting functions to optimize energy resolution and throughput. Photons striking a semi-conductor detector generate current which is amplified, converted to a voltage step, and fed to a fast analog-to-digital converter (ADC) for pile-up rejection and a slow ADC whose output is examined for low-energy pile-up, slope corrected, and buffered for photon energy measurement. Pile-up is detected with a unique pair of leading and trailing weighting functions whose outputs have sharp rising and falling edges respectively, nearly independent of photon energy. Digital triangular shaping is used to locate the step in the buffer. Asymmetry of the triangular response is used to reject very low-energy pile-up. The step is also rejected if the average noise nearby exceeds a threshold.

Abstract: A concurrent recording and reproducing optical disc has a magneto-optical medium film coated on a ROM disc having rows of pits. The magneto-optical film is arranged by a predetermined interval between the two adjacent rows of the pit rows. The predetermined interval is determined by a dark Airy disc circle band of a beam spot obtained by focusing a light beam on the concurrent recording and reproducing optical disc. Preferably, two light beams are focused on the optical disc to provide first and second beam spots. The first beam spot is focused on one of the pit rows, and the second beam spot is focused on an area between two selected pit rows.

Abstract: The present invention is a method for improving the estimation of physical properties of a material, based on the infrared spectrum of the material, by concatenating additional data obtained from other measurement techniques to the infrared spectrum to fill the voids in the spectral data resulting from a lack of sensitivity by infrared spectrometers to trace compounds in the material. The augmented spectral data then is used to produce a calibration model for estimating the physical properties of the material.

Abstract: A nuclear spectrometer employs asymmetrical weighting functions to optimize energy resolution and throughput. Photons striking a semi-conductor detector generate current which is amplified, converted to a voltage step, and fed to a fast analog-to-digital converter (ADC) for pile-up rejection and a slow ADC whose output is examined for low-energy pile-up, slope corrected, and buffered for photon energy measurement. Pile-up is detected with a unique pair of leading and trailing weighting functions whose outputs have sharp rising and falling edges respectively, nearly independent of photon energy. Digital triangular shaping is used to locate the step in the buffer. Asymmetry of the triangular response is used to reject very low-energy pile-up. The step is also rejected if the average noise nearby exceeds a threshold.

Abstract: A Computed Tomography system for obtaining annular views of cylindrical octs, in which x-ray scanning is done of an annulus of the objects, and the computation necessary to derive the reconstructed image in polar coordinates is limited to the annulus of the objects, ignoring the other areas. Normalization is done to adjust the reconstructed image to the number of scans made of the various areas of the object.