568 Appendix B Image Reference
CheckBy3
Description The active video area is equally divided into a 3x3 checkerboard of black and white boxes.
The primary version has four white boxes as shown in the image below. The secondary
version has five white boxes (reverse).
Test Contrast ratio
Purpose The pattern is based on a proposed ANSI method of measuring the contrast ratio of video
projection systems.
Method Using a light meter probe, measure and record the light-level reading (in foot lamberts) in
the center of each of the black and white boxes. The contrast ratio is expressed as the
average of all of the white readings divided by the average of all of the black readings.
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