Share Email Print
cover

Proceedings Paper

Inverting the perceptual transform
Author(s): Adar Pelah
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Images are filtered by the various stages of visual processing and undergo a perceptual transformation. To begin to quantify this process, the appearance of sinewave gratings, images with a sinusoidal luminance profile, was studied. The most salient features of these images is that at high contrast they do not in general appear sinusoidal. A logarithmic transform, based on Fechner's law, is suggested as a first approximation to the perceptual transform in the luminance domain, and shown to characterize the apparent luminance profiles of sinewave gratings. Furthermore, the sinusoidal image profile can be pre-processed (inverse transformed) to create a new image which, when viewed, reverses to a large extent the perceptual distortions discussed above. This `corrected' image would appear as if the combined effects of the perceptual transform had not acted, making the now non-sinusoidal profile conform much more closely to our symmetrical expectations of a sinusoidal appearance. The principle of inversion used here is suggested as a general way of testing the validity of some human vision models proposed to achieve better image processing algorithms based on visual perception.

Paper Details

Date Published: 1 May 1994
PDF: 8 pages
Proc. SPIE 2179, Human Vision, Visual Processing, and Digital Display V, (1 May 1994); doi: 10.1117/12.172659
Show Author Affiliations
Adar Pelah, Univ. of Cambridge (United Kingdom)


Published in SPIE Proceedings Vol. 2179:
Human Vision, Visual Processing, and Digital Display V
Bernice E. Rogowitz; Jan P. Allebach, Editor(s)

© SPIE. Terms of Use
Back to Top