Dithering for 12-bit true-color graphics

Three approaches that together improve the quality of dithered images by decreasing the intensity error and distributing the remaining quantization error more effectively, both spatially and across the intensity range, are described. The first method improves the intensity error distribution. The second method, which is complementary to the first, improves the quality of low-intensity vectors and surfaces through the use of a nonlinear quantizer. The third method specifically improves vector dithering. The primary focus is on dithering from 24 b to 12 b RGB but 24-b to 15-b dithering (5 bits each of red, green, and blue) were also investigated.<
>