BIT-STEALING: HOW TO GET 1786 OR MORE GREY LEVELS FROM AN 8-BIT COLOR MONITOR

Christopher W. Tyler, Hoover Chan, Lei Liu, Brennan McBride and Leonid Kontsevich

Smith-Kettlewell Eye Research Institute

2232 Webster Street, San Francisco CA 94115

ABSTRACT

The precision of human vision requires displays to be accurate to about 0.2% of the luminance range. We present a technique by which this grey-level precision can be achieved with the use of an 8-bit color monitor. The basic idea is to "steal" adjacent bits from the color variation for use in increasing the precision of the luminance variation. On a monitor with 8 bits per color gun, the technique can provide 1786 or more grey levels at a cost of one bit of color jitter, with standard D/A hardware. The color variations are invisible under almost all conditions.