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The perceived slant of visual surfaces—optical and geographical.

1952; American Psychological Association; Volume: 44; Issue: 1 Linguagem: Inglês

10.1037/h0060729

1946-1941

James J. Gibson, Janet Cornsweet,

3D Surveying and Cultural Heritage

One of the properties of a visual surface along with hardness, distance, and color-with-illumination, is that of slant.This term must be understood to include not-slanted as well as slanted; in other words the variable consists of opposite qualities having zero slant as a norm.There is evidence that optical slant, so-called, is determined by stimulation.When vision is monocular and the head is motionless, this quality seems to depend on the gradient of the density of the "texture" of the retinal image (1).The experiment which appeared to demonstrate this psychophysical correspondence, however, is defective in that the procedure failed to isolate the quality of optical slant from a congruent quality of geographical slant which accompanied it.This failure should be amended if possible.Moreover the two kinds of slant need to be denned and their relevance to spaceperception discussed.Consider first the impression of slant embodied in the face of an object-a bounded surface, or a segment of an array of surfaces.It can be studied in the following situation.The 0 sits in an ordinary room with his gaze horizontally straight ahead and fixates the center of a surface such as a sheet of textured cardboard.This surface is then rotated by E around a horizontal axis, either forward or back-