Graphics Reference
In-Depth Information
Fig. 1.16
This programmed logic array (PLA) converts the cross-correlation bits to counter-control
signals. If an image has no light pixel adjacent to one in the previous frame, the “Jump” output is
asserted to signal this exception, and the counters are not moved, by not asserting either “Half” or
“Full” as the increment size
Fig. 1.17
Four-phase quadrature encoding, or 2-bit Gray code, is reported in each dimension.
Motion in one direction makes square waves in quadrature (90
ⓦ
out of phase with each other)
