Cursor generator for use in computerized tomography and other image

Abstract

A composite video signal waveform is fed through a video mixer and to a video monitor for displaying a raster scanned image on its screen. Signals are also fed through the mixer for causing a cursor having distinctive light intensity to be overlayed on the image. Programs for defining multiple cursors are stored in a readable memory. A microprocessor uses the programs for generating cursor parameters for each horizontal raster line and these are stored in a random access memory. A direct memory access controller responds to occurrence of each horizontal sync pulse by loading the cursor parameters for each corresponding raster line into counters which determine the starting point and end point of the cursor in that line or the width of the particular cursor line. During the interval representative of cursor line width, signals are fed through the mixer for altering the brightness intensity of the display. The random access memory is read out on a horizontal line-by-horizontal line basis so as to produce a whole cursor configuration between vertical blanking intervals. Operator interactive controls are provided for moving and angulating cursors.