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Proceedings Paper

Local luminance effect on spatial summation in the foveal vision and its implication on image artifact classification
Author(s): Chien-Chung Chen; San-Yuan Lin; Hui-Ya G. Han; Sheng-Tzung Kuo; Kuo-Chung Huang
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Paper Abstract

We investigated the spatial summation effect on pedestals with difference luminance. The targets were luminance modulation defined by Gaussian functions. The size of the Gaussian spot was determined by the scale parameter (standard deviation, σ) which ranged from 0.13°to 1.04°. The local luminance pedestal (2° radius) had mean luminance ranged from 2.9 to 29cd/m2. The no-pedestal condition had a mean luminance 58cd/m2. We used a QUEST adaptive threshold seeking procedure and 2AFC paradigm to measure the target contrast threshold at different target sizes (spatial summation curve) and pedestal luminance. The target threshold decreased as the target spatial extent increased with a slope -0.5 on log-log coordinates. However, if the target size was large enough (σ>0.3°), there was little, if any, threshold reduction as the target size further increased. The spatial summation curve had the same shape at all pedestal luminance levels. The effect of the pedestal was to shift the summation curve vertically on log-log coordinates. Hence, the size and the luminance effects on target detection are separable. The visibility of the Gaussian spot can be modeled by a function with a form f(L)*g(σ) where f(L) is a function of local luminance and g(σ) is a function of size.

Paper Details

Date Published: 3 February 2006
PDF: 9 pages
Proc. SPIE 6057, Human Vision and Electronic Imaging XI, 605703 (3 February 2006); doi: 10.1117/12.642010
Show Author Affiliations
Chien-Chung Chen, National Taiwan Univ. (Taiwan)
San-Yuan Lin, National Taiwan Univ. (Taiwan)
Hui-Ya G. Han, National Taiwan Univ. (Taiwan)
Sheng-Tzung Kuo, Taiwan TFT LCD Association (Taiwan)
Kuo-Chung Huang, Industrial Technology Research Institute (Taiwan)


Published in SPIE Proceedings Vol. 6057:
Human Vision and Electronic Imaging XI
Bernice E. Rogowitz; Thrasyvoulos N. Pappas; Scott J. Daly, Editor(s)

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