Motion parallax: effects of blur, contrast, and field size in normal and low vision.
Can people with different forms of low vision use motion parallax to improve depth judgments? We used a staircase method to compare depth thresholds using motion parallax and static viewing. We tested eighteen normal-vision subjects with a range of simulated deficits in acuity, contrast sensitivity, and simulated peripheral-field loss, and ten low-vision subjects with a wide range of acuity, contrast sensitivity, and field loss. Subjects viewed three vertical cylinders monocularly and indicated which one was at a different depth from the other two. For motion-parallax trials, observers moved their heads (in a viewing assembly on rollers) from side to side over a range of 6-12 cm. For static trials, the viewing assembly was fixed in place. Normal-vision subjects' depth thresholds with motion parallax were significantly smaller than those with static viewing by an average factor of 1.95 (p < 0.05) across all levels of acuity and contrast. For low-vision observers, the depth thresholds exhibited large individual differences; however, the motion-parallax thresholds were smaller than the static thresholds by an average factor of 2.05 (p < 0.01). These findings indicate that motion parallax can provide useful depth information for people with low vision.
Jobling
J T
JT
Minnesota Laboratory for Low-Vision Research, Department of Psychology, University of Minnesota, Minneapolis 55455, USA.
Mansfield
J S
JS
Legge
G E
GE
Menge
M R
MR
D000293:Adolescent; D000328:Adult; D003867:Depth Perception; D006801:Humans; D008875:Middle Aged; D009039:Motion Perception; D011581:Psychological Tests; D014786:Vision Disorders / Q000523:psychology*