A CT image processor for use in X-ray computerized tomographic system including an X-ray source for providing fan beams on an object being examined, a multichannel X-ray detector for detecting the fan beams transmitted through the object and a processor for reproducing a sectional image of the object including circuitry for obtaining a back projection of the signal obtained from the multichannel radioactive ray detectors, the processor circuitry also having means for rearranging the order of the...

Apparatus and method for mounting on an existing x-ray simulator and calculating a back projected computed tomographic image. The detector array is linear and outputs signals from the photodiodes mounted therein to a preprocessor for smoothing, correcting and filtering and subsequent processing to transform the signal from that produced by an x-ray originating from a fan beam source, e.g., in a polar coordinate system, into the signal which would have been produced by a detector in an array on w...

A method of reducing image helical scanning; artifacts in computed tomography imaging systems divides 360.degree. of projection data into two half scans. Separate weighting functions are applied to the two half scans and they are reconstructed to an image per conventional reconstruction methods. The weighting functions provide effective interpolation and extrapolation of the half scan data to a slice plane centered in the projection data. In one embodiment, the weighting functions are feathered ...

Apparatus and method for mounting on an existing x-ray simulator and calculating a back projected computed tomographic image. The detector array is linear and outputs signals from the photodiodes mounted therein to a preprocessor for smoothing, correcting and filtering and subsequent processing to transform the signal from that produced by an x-ray originating from a fan beam source, e.g., in a polar coordinate system, into the signal which would have been produced by a detector in an array on w...

An improved method for computed tomographic scanning is disclosed. A beam of electromagnetic radiation subtending an angle .phi. is alternately translated and rotated past a patient. The intensity of the beam is detected by an array after the radiation passes the patient and a reconstructed image created from the detected intensities. Each rotation of the array is through an angle less than the angle .phi. subtended by the array producing redundant intensity readings for similarly oriented beam ...

Radiographic apparatus reconstituting an image by processing by means of a computer the signals delivered by a detector measuring the coefficient of absorption of a body through which an X-ray beam passes. A plurality of detectors disposed in a fan arrangement are used, whereby it is possible to decrease the number of scanning stations. According to the invention, this number of stations is an odd number for a complete revolution. Further, a number of detectors in excess is used for a given incl...

A computerized tomography apparatus comprises a source rotating about an object for directing fan-shaped beams of radiation towards the object, a detector for detecting the fan-shaped beams of radiation through the object and producing projection data representative of radiation intensity integrated along the beams at successive different views, and estimating circuitry for providing interpolated projection data between adjacent views in addition to projection data from the detector by using a p...

During computer tomography examinations, ring-like artefacts occasionally occur because the X-ray source becomes hot, so that the X-ray focus changes its position in space. Because the distance between the detector and the diaphragm which stops the radiation beam is several times larger than the distance between the X-ray focus and the diaphragm, the shifting of the radiation beam on the detector is even greater. If the detector consists of detection elements which are not exactly identical, it ...

Parallel accumulation of the density functions of image picture elements is done for a number of elements located at the same radial distance from the axis of rotation for the fan-beam scanner. This allows the computation of weighting factor to be done in common for these elements, as well as the computation of interpolation coefficients for ray sums not registering exactly with x-ray detectors.

A method of reducing image artifacts in images acquired with fan beam, helical scanning, tomographic imaging systems rebins the fan beam data into parallel beam projection sets. Data is spliced from first areas of the parallel beam projection data to second areas to create a set of 2.pi. radians of complete projection data. The 2.pi. of projection data is divided into half scans which are interpolated and extrapolated to produce a new projection set at the slice plane with reduced helical offset...