scholarly journals Angular subtense effects on perception of polar and parallel projections of cubes

1993 ◽  
Vol 54 (6) ◽  
pp. 763-772 ◽  
Author(s):  
Andrea L. Nicholls ◽  
John M. Kennedy
Keyword(s):  
Angular Subtense

Relative Effects of Raster Scan Lines and Image Subtense on Symbol Legibility on Television

1969 ◽  
Vol 11 (4) ◽  
pp. 331-338 ◽  
Author(s):  
John C. Hemingway ◽  
Ronald A. Erickson
Keyword(s):  
Visual Acuity ◽  
Response Times ◽  
Forced Choice ◽  
Image Size ◽  
Line Number ◽  
Raster Scan ◽  
Different Levels ◽  
Choice Method ◽  
Angular Subtense

This experiment examined the relative effects of (1) image size and (2) number of TV raster lines making up the image upon an observer's ability to identify 16 different geometric symbols on TV. Four raster-line values per symbol height were each tested at three image angular subtenses. Eight subjects were told to identify 25 symbols for each of the 12 conditions; all had 20/12 near and far visual acuity or better. The forced-choice method was used; no limits were placed on response times. The results showed that (1) at least eight raster lines per symbol height and (2) a symbol subtense of 10' of arc are necessary to obtain good symbol legibility on TV. An equation is developed from these and other data which quantifies the tradeoff between line number and angular subtense for different levels of performance.

Peaking of response in locust visual interneurones to objects of small angular subtense

1976 ◽  
Vol 22 (11) ◽  
pp. 1475-1484 ◽  
Author(s):  
W.T. Catton
Keyword(s):  
Angular Subtense

Factors Influencing the Apparent Rotation of a Line on Radially Transformed Backgrounds

Perception ◽  
1983 ◽  
Vol 12 (3) ◽  
pp. 313-322 ◽  
Author(s):  
Nicholas J Wade ◽  
Michael T Swanston ◽  
Hiroshi Ono ◽  
Peter M Wenderoth
Keyword(s):  
Spatial Frequency ◽  
Oblique Line ◽  
Zoom Lens ◽  
Television System ◽  
Vertical Grating ◽  
Apparent Rotation ◽  
Factors Influencing ◽  
Constant Rate ◽  
Orientation Anisotropy ◽  
Angular Subtense

The expansion and contraction of a display consisting of a stationary grating with a superimposed inclined line leads to the apparent rotation of the line. This phenomenon has been investigated in six experiments with the use of a television system with a motorized zoom lens to effect such transformations. The maximum apparent line rotation occurs with the line at 45° to the grating. In experiment 1 a greater magnitude of apparent rotation was found with a vertical grating and an oblique line than vice versa. Zoom-out (contraction) also produced greater rotation than zoom-in (expansion). The orientation anisotropy was not dependent upon the orientation of the display to the retinal meridian (experiment 2): the extent of apparent line rotation was approximately the same with a vertical grating when the head was upright or tilted so that the retinal meridian was at 45°. At a constant rate of zooming, a zoom duration of 2 s produced a larger apparent line rotation than one of 1 s, but it was not influenced by the initial angular subtense of the superimposed line (experiment 3). Neither the spatial frequency of the grating nor the width of the line affected the apparent rotation (experiments 4, 5, and 6). Experiment 5 compared the apparent rotation when the display was zoomed (i) with a fixed surround and (ii) with a surround that also expanded during zooming. The magnitude of rotation in the latter condition was reduced to about 25% of that with a fixed surround. The results are discussed in terms of the discrepancy between the perceived transformations of the background grating and the superimposed line.

Sun Angular Subtense

2020 ◽  
Author(s):  
Julius E. Yellowhair
Keyword(s):  
Angular Subtense

Bloch's Law for Brief Flashes of Large Angular Subtense

1973 ◽  
Vol 36 (3_suppl) ◽  
pp. 1055-1061 ◽  
Author(s):  
William W. Dawson ◽  
Joseph M. Harrison
Keyword(s):  
Stimulus Duration ◽  
Visual Angle ◽  
Critical Period ◽  
Large Area ◽  
Peak Intensity ◽  
Time Correction ◽  
Angular Subtense ◽  
Linear Intensity

Stimuli which subtended a 61° visual angle were used to measure ΔI against a concentric field at 273 trolands. Peak intensity was adjusted to threshold as the stimulus duration was reduced in steps from 1 sec. to 100 microsec. Data from 10 observers allowed the calculation of a variance measure and a slope constant. Reciprocity held only at very short durations. The critical period for this stimulus was about 1 msec. Large errors may be encountered if linear intensity-time correction techniques like the troland-second are applied to large-area brief flashes.

Color Naming as a Function of Stimulus Luminance, Angular Subtense, and Practice

1985 ◽  
Vol 29 (11) ◽  
pp. 1070-1074 ◽  
Author(s):  
David L. Post ◽  
Frances A. Greene
Keyword(s):  
Color Naming ◽  
Stimulus Luminance ◽  
Angular Subtense

Color Discrimination under Reduced Angular Subtense and Luminance

1969 ◽  
Vol 59 (2) ◽  
pp. 131 ◽  
Author(s):  
G. T. Yonemura ◽  
M. Kasuya
Keyword(s):  
Color Discrimination ◽  
Angular Subtense

Angular subtense requirements for colored CRT symbology

1984 ◽  
Author(s):  
David L. Post ◽  
Denise Sheibenberger
Keyword(s):  
Angular Subtense

The effect of vertical angular subtense on perception of slant from horizontal size disparity

2009 ◽  
Vol 16 (4) ◽  
pp. 449-451
Author(s):  
Masahiro Ishii
Keyword(s):  
Size Disparity ◽  
Horizontal Size ◽  
Angular Subtense
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