James E Phelps

US Patent:

41588380, Jun 19, 1979

Filed:

Jan 16, 1978

Appl. No.:

5/869721

Inventors:

Michael D. Pruznick - Huntington Beach CA
Bruce W. Keller - Scotland AR
James R. Phelps - Torrance CA
Gerald Wolfson - Los Angeles CA
James L. Heard - Torrance CA

Assignee:

Hughes Aircraft Company - Culver City CA

International Classification:

G06F 314

US Classification:

340750

Abstract:

A symbol smoothing system for synthetically increasing the effective resolution of an in-raster symbol generator memory by a factor of four. The system stores a special three bit code in selected memory elements representative of the existing and past two memory lines with the code actually being a video brightness distribution and positioning offset code. A code number in a single memory cell defines positional and intensity information for the display elements corresponding to that memory cell and to selected surrounding eight memory cells, all of the memory cells having time or positional correspondence to display element positions. The stored codes in the surrounding memory cells, as well as the instantaneous memory cell being decoded, provide intensity levels which are combined at selected display element positions. The video data input for each memory cell consists of the fractional X and Y position bit and symbol type bit and from each memory element, eight additional display elements are developed having selected brightness levels. By decoding this code bit information, the in-raster symbology provides a smooth transition from one display line to the next so as to eliminate the staircase effect in rotated or non-orthogonal lines.