Abstract: A control unit for the brightness of video signals on a raster scan display is provided with a random-access memory. The data stored in each element of this memory determines the brightness of the video signals on the raster scan display at a position corresponding with this element. In response to the video data supplied to the control unit and the brightness data in the random-access memory a logical unit provides new brightness data which overwrites the brightness data in the memory.

Abstract: In a digital scan converter for displaying video data provided by a radar sensor on a raster scan display, the video data is stored in a radar input buffer at addresses corresponding to the pattern according to which the field of view of the radar sensor is scanned, and taken over in a random-access memory. The random-access memory consists of N .times. N submemories, all containing a .times. a memory elements and all being simultaneously accessible. For the range scan in any azimuth value (.phi.) the range considered is divided into n (n.ltoreq.N) segments of each i k range increments .DELTA.r, where the length k.DELTA.r of each of said segments equals at least the range represented by "a" memory elements, multiplied by a factor .sqroot.2. An address generating circuit generates the addresses x = x.sub.c + (lk+m).DELTA.r cos .phi. and y = y.sub.c + (lk+m).DELTA.r sin .phi. where x.sub.c and y.sub. c represent the coordinates of the radar sensor position, l = 0, 1, 2, . . .