Figure 6.

Our DLP-based dichoptic visual test system. (a) The frame sync relay allows us to switch between the color wheel, the computer, or a 60-Hz signal generator. (b) Conceptual diagram of the shutter controller. Delay after the onset of the frame sync pulse is used to time the shutter events (i.e., open and close) in each frame (Fig. 5). The rows of circles on the right represent two cycles (frames) of shutter events. Each cycle has three periods that are established by the on periods of three flip-flops, which, in turn, are set and reset at the times the counter reaches the values set in the switches of their associated comparators. First the “red” flip-flop opens the right goggle lens (open circle) while the left goggle lens remains closed (filled), then the “blue” flip-flop opens the left goggle lens while the right goggle lens is closed. The gray circles in the shutter event cycle (third and sixth events as shown) represent the state of the “green” counter, if connected. The four-way switch allows monocular or binocular or no shutter opening. At the switch location shown, the gray circles would represent both goggle lenses being open (a binocular view), although we have not used that setting in our applications.