Entries selected from the look-up palette are sent to the color/grayscale space/timebase dither generator. Each 4-bit value is used to select one of 15 intensity levels. Note that two of the 16 dither values are identical (most intense). The gray/color intensity is controlled by turning individual pixels on and off at varying periodic rates. More intense grays/colors are produced by making the average time that the pixel is off longer than the average time that it is on. The dither generator also uses the intensity of adjacent pixels in its calculations to give the screen image a smooth appearance. The proprietary dither algorithm is optimized to provide a range of intensity values that match the eye’s visual perception of color/gray gradations. In color mode, three separate dither blocks are used to process the three color components: red, green and blue.
The duty cycle and resultant intensity level for all 15 color/grayscale levels is summarized in Table 1.7.
|Dither Value(4-bit value from palette)||Intensity(0% is white)||Modulation Rate(ratio of ON to ON+OFF pixels)|