Effect on visual-recognition performance of misregistration and overlap for a biocular helmet-mounted display

A within subjects design was employed to evaluate three factors: dipvergence (.45 to 1 .8 degrees of subtended angle), divergence (.83 to 3.3 degrees), and overlap (35 to 100 percent). Using a configuration composed of a computer graphics engine, two monitors and a two channel optical relay system focused at infinity, imagery simulating FLIR detail and contrast was shown to subjects who searched the field for dynamic alphanumeric and geometric targets. Objective dependent measures were target recognition accuracy and response time. Subjective measures included verbal report of headaches, eyestrain, blurred or double vision any time during experimental trials. Although the extent of misregistration was not statistically significant, a breakpoint in performance was observed for each type of misalignment. Accuracy and latency measures indicated that performance deteriorated significantly as overlap area was decreased. Subjective measures indicated subjects were aware of blurring and doubling as misalignment levels increased and complained of eyestrain when overlap area was decreased.