The Spatial and Temporal Parameters of Velocity Discrimination
Abstract
The target duration required for the precise discrimination of velocity is quite short, amounting to about 100 msec for a single moving dot or line target. While stroboscopic motion is an adequate substitute for continuous motion in velocity discrimination, optimal discrimination depends on the use of a strobe rate greater than 10 Hz. Generally human observers have difficulty detecting acceleration in moving targets. Over small distances (0.5-1 deg), timing signals from adjacent targets presented in a sequence are pooled, so that information about their relative onset time is lost. For example, given three adjacent lines, separated spatially by 0.1 deg and presented in a sequence (apparent motion) observers are unable to discriminate between a sequence in which a 10 msec interval separates the second from the reverse order (30 msec followed by 10 msec). Velocity discrimination is not affected by blur. Sinusoidal grating targets of 3 cyl/deg or lower produce excellent discrimination. Sinusoidal gratings above 3 cycles per degree in spatial frequency are not adequate for fast velocities (> 1 deg/sec). Keywords: Motion human performance; Velocity discrimination; Acceleration detection vision.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 20, 1984
- Accession Number
- ADA158735
Entities
People
- Suzanne P. Mckee