Abstract: In fan beam X-ray scanners operating with a large number of detectors, errors at and near the center of rotation are caused by the fact that the radiation absorption in said area is substantially always measured by the same detectors and that the sensitivity of all detectors is not exactly the same. The invention provides an improvement in that the measurement is carried out with a larger number of detectors than is necessary for the measurement of the scanning field and that the detectors pivot during the measurement. As a result, the absorption in the center of rotation is measured by different detectors so that, for a sufficient number of detectors the different sensitivities, errors are averaged and thus reduced or cancelled.

Abstract: A method of and a device for the coding and decoding of an object by means of point-shaped radiation sources. The point sources are subdivided in groups which successively irradiate the object. Two sources distributions can be derived from the groups of radiation sources (a negative radiation intensity is assigned to at least one group), the sum of the autocorrelation functions thereof having the value "0" outside the origin. The coded images generated by means of the various groups are recorded (and also their negatives). Combinations of a coded image and a negative are decoded via point holograms or lens matrices, thus forming a subimage. The sum of all subimages forms an object image which is free of artefacts.

Abstract: A device for examining a body section by means of x-radiation including a plurality of detectors arranged to intercept radiation passing through the body in straight lines or strips and a calculating circuit which interpolates, on the basis of absorption values measured, absorption values which can be expected along sets of mutually extending strips which cross each other at different angles. The absorption in the section of the body can then be calculated in known manner on the basis of these values.