Threshold-based lossy reduction color compression

• Main Authors: KULSHRESTHA NARAYAN, MCALLISTER DAVID KIRK, MOLNAR STEVEN E
• Format: Patent
• Language: English
• Published: 10.12.2013
• Subjects: ADVERTISING; APPARATUS SPECIALLY ADAPTED THEREFOR; ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICESUSING STATIC MEANS TO PRESENT VARIABLE INFORMATION; CALCULATING; CINEMATOGRAPHY; COMPUTING; COUNTING; CRYPTOGRAPHY; DISPLAY; EDUCATION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; ELECTROGRAPHY; HANDLING RECORD CARRIERS; HOLOGRAPHY; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; MATERIALS THEREFOR; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; PRESENTATION OF DATA; RECOGNITION OF DATA; RECORD CARRIERS; SEALS

One embodiment of the present invention sets forth a technique for compressing color data. Color data for a tile including multiple samples is compressed based on an equality comparison and a threshold comparison based on a programmable threshold value. The equality comparison is performed on a first portion of the color data that includes at least exponent and sign fields of floating point format values or high order bits of integer format values. The threshold comparison is performed on a second portion of the color data that includes mantissa fields of floating point format values or low order bits of integer format values. The equality comparison and threshold comparison are used to select either computed averages of the pixel components or the original color data as the output color data for the tile. When the threshold is set to zero, only tiles that can be compressed without loss are compressed.