Abstract: A method for deriving character features in a character recognition system for recognising characters, such as letters and digits, and a character recognition system in which the method is applied. After deriving a character description from a recorded image pattern of a character to be recognised, a unique point Pi of said character description is appended, by means of a distance transform, to each point Ri of a subset R={Ri/i=1, - - - ,N} of preselected reference points in the plane of said image pattern. Feature values of one or more features possessed by the character description in each appended unique point are then determined. If the character description is a contour description, the unique point Pi appended to each reference point Ri is that point where the reference point Ri has the shortest distance D(Ri) to the contour of the character, and the character features selected are the shortest distance D(Ri) and the direction H(Ri) of the contour in the appended point Pi.

Abstract: Method and device for controlling a TST-switching network. The control device (5) controls the network in such a way that in one frame period in each of the .lambda. internal time slots the (n x n)-switching matrix (6) is set according to the switching pattern of an (n x n)-permutation matrix, so that in each time slot always n switching paths between the input buffer (3 or 4) and the output buffer (7 or 8) are set up in parallel. Consequently, the network is free from blockings for at most n x .lambda. switching paths.

Abstract: Method for controlling an antenna of an earth station for telecommunication via satellites, which antenna is provided with means to determine the position of the antenna and with means to ascertain the strength of the received signal, the direction of each change of position to be made by the antenna being derived from the change of the signal strength and the attendant change of position in consequence of the uncontrolled changes of position made by the antenna with respect to the position chosen.

Abstract: Method and device for eliminating the background brightness variation of a video signal, in which the background brightness in each line of the frame of a video signal has its low frequency brightness signal a(t) limited, as well as being limited by its deviation from the limited brightness of the preceding line of frame. This can be expressed mathematically by stating that .vertline.V(t)-a(t).vertline. is minimized by means of a(t) on the marginal conditions.vertline.a(t)-a(t-T).vertline..ltoreq..epsilon. and.vertline.a(t)-a(t-.DELTA.).vertline..ltoreq..epsilon.,in whichV(t)=the video signal V at the moment t;a(t)=an estimation of the background brightness variation a(t);T=the duration of a line;.DELTA.=h/b T/k, in which h/b=the height/width ratio of the image and k=the number of lines per frame, and.epsilon.=the maximum value of the derivative of a(t) multiplied by .DELTA..