Experiments in Texture Perception
Annual rept. 1 Jun 1974-31 May 1975
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF PSYCHOLOGY
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Visual textures may be described completely by their spatial frequency components. For one-dimensional textures whose luminance varies only along the X-axis of the display, the descriptive elements are gratings that have sinusoidal modulations of luminance. Although any arbitrary 1-dimensional blurred texture may require a large number of sinusoidal components for its complete physical description, only 4 components are needed to create a texture that appears the same to the human observer. The human visual system seems does not act like a spectral analyser, but rather appears to process spatial frequency information by filtering operations, at least for 1-dimensional texture patterns. In the more general case, textures will have luminance distributions varying in both X and Y dimensions. A new graphics display is being built to test for the minimum number of spatial frequencies required to simulate 2-dimensional texture patterns. The apparatus will permit on-line control of the amplitude contrast of the X,Y frequency Fourier components that make up the texture displayed. The observer can generate a texture that appears identical to another having a different and more complex spatial frequency content. If it is found that only 4 spatial frequency components are necessary to simulate all 2-dimensional textures, one may design a scheme to transmit visual information about textures that offers considerable saving in channel capacity.
- Anatomy and Physiology