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Results for “Depth Perception”

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At least 19 recordsLinked to original sources
PubMed1979

Influence of sonic noise on human stereoscopic depth perception.

Scientific establishment of the no-effect response to finite levels of exposure to a physical or chemical agent is indeed a rigorous exercise and is frequently controversial. In earlier research by Slutsky under direction of the senior author, a statistically significant increase in stereoscopic depth perception error was noted among 24 test subjects exposed to high intensity noise. Additional extensive research reported in this paper indicates that error in stereoscopic depth perception is not significantly altered by exposure to continuous white noise of short duration at levels ranging from 70 to 115 dBA. Furthernore, exposure of humans for periods of a few minutes to white noise in octave bands centered on 250 Hz, 1000 Hz, 4 kHz and 16 kHz at 115 dB does not affect their depth perception measured by the Howard-Dolman test. A comprehensive analysis of depth perception errors measured under noise exposure conditions (n = 4040) in comparison with those obtained under control conditions (n = 1430) produced a mean change in error of -0.38 mm, a statistically insignificant difference (p = 0.17). Even if such an error were attributable to high level noise, it should be noted that minus sign designates an improvement of depth perception in noise and that it is difficult to imagine visual tasks in which change in error of +/-0.38 mm at a distance of 6.0 meters is meaningful.

Depth Perception↗
PubMed1975

Depth perception and location of brain lesions.

Depth perception was examined in 50 patients with brain lesions and in 16 controls using a polaroid test (Titmus). Error percentage and response time were measured. Intellectually impaired patients performed significantly worse than intellectually normal patients. On the other hand, location of the cerebral lesion (right, left, or generalized) had no significant effect; zero error percentages were observed among intellectually normal patients even with right or left parietal lesions. Intellectually normal patients did not differ from healthy controls.

Brain Diseases↗
PubMed1978

Paradoxical sleep and depth perception.

It has been hypothesised that one possible function of paradoxical (REM) sleep is the maintenance of facilitation of co-ordinated eye movements. A prediction from this hypothesis is that binocular depth perception will be more accurate at the end of periods of paradoxical sleep than at the beginning. The results from previous studies are conflicting. Using two groups of eight healthy male volunteers in a two factor repeated measures design, it was found that for a period of paradoxical sleep in the second half of the night only, there was an improvement in binocular depth perception accuracy between the beginning and end of paradoxical sleep. The accuracy at the end of the paradoxical sleep was not significantly different to that on going to bed or on awakening in the morning; the effect was due to a large decrease in accuracy at the start of the REM period. There was no effect of paradoxical sleep on binocular depth perception in the early part of the night. Monocular depth perception accuracy was unaffected by paradoxical sleep.

Adolescent↗
PubMed1979

Assessment of depth perception in cats.

A behavioural method is described for the assessment of depth perception of kittens. Measurement is made of the smallest separation in depth that can be discriminated between two adjacent stimuli under both monocular and binocular viewing conditions. Normal animals can discriminate much smaller separations in depth when using two eyes than with monocular viewing, implying the presence of a cue to depth that is uniquely available with binocular viewing. The test provides a quick and reliable way of screening animals for stereopsis.

Animals↗
PubMed1978

Role of two-dimensional surface characteristics in pictorial depth perception.

The purpose of the present experiment was to test the hypothesis that flat surface information for the plane of projection is the essential difference between ordinary and pictorial perception. Adults were asked to make relative size judgments of pairs of squares and triangles placed and pictured at various distances. The conditions were: real scene controls, life-size slides and prints, and real scenes viewed through clear glass, textured glass, a screen and a 50-mm lens. The error rate was significantly lower with real scenes than with either slides or prints which did not differ. The control data for real scenes were used for comparison to test for the effects of interposed flat surfaces on size judgments of real scenes. Viewing real scenes through either a clear glass pane or a 50-mm lens increased the error rate two and one-half times that of the controls for real scenes. Neither textured glass nor a screen significantly affected error rate. Results were interpreted as supporting the hypothesis that information about a flat surface for the plane of projection is the critical variable determining the special character of picture perception.

Depth Perception↗
PubMed1975

Depth perception in the rat (Rattus Norvegicus): prepotency of three-dimensional over two-dimensional surfaces.

The descent behavior to two- and three-dimensional surfaces in a depth situation was measured and compared for 45-50 days-old hooded rats. When depth differences between surfaces were controlled, significantly more descents were made to three-dimensional than to the two-dimensional surface. The results suggest that a three-dimensional surface--more representative of an animal's natural terrain--provides a more informative environment for motion parallax than does a two-dimensional one.

Animals↗
PubMed1979

Motion parallax as an independent cue for depth perception.

The perspective transformations of the retinal image, produced by either the movement of an observer or the movement of objects in the visual world, were found to produce a reliable, consistent, and unambiguous impression of relative depth in the absence of all other cues to depth and distance. The stimulus displays consisted of computer-generated random-dot patterns that could be transformed by each movement of the observer or the display oscilloscope to simulate the relative movement information produced by a three-dimensional surface. Using a stereoscopic matching task, the second experiment showed that the perceived depth from parallax transformations is in close agreement with the degree of relative image displacement, as well as producing a compelling impression of three-dimensionality not unlike that found with random-dot stereograms.

Cues↗
PubMed1976

Depth perception after infant and adult visual neocortical lesions in light- and dark-reared rats.

In 2 experiments the behavior of light- and dark-reared infant- and adult-operated striate rats were compared at 20-160 days of age on a visual cliff apparatus in which the depth of the deep side could be varied. Differential depth thresholds revealed that depth discriminative ability did not develop normally following removal of the striate cortex in infancy. Further, infant-operates who were reared in darkness following their operations performed less well than their light-reared, infant-operated counterparts. The infant-operated animals, regardless of their postoperative rearing condition, performed significantly better than did adult-operated animals after comparable post-operative recovery periods and testing. The results are discussed in terms of further specification of the role played by age of operation and by the interaction between visual experience and age of operation.

Age Factors↗