Journal of Xidian University

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Experimental characterization of the human vision contrast threshold for the triangle pattern

ZHANG Dongyang;ZHANG Jianqi   

  1. (School of Physics and Optoelectronic Engineering, Xidian Univ., Xi'an 710071, China)
  • Received:2015-10-13 Online:2016-12-20 Published:2017-01-19

Abstract:

The human vision contrast threshold characteristic is an important basis for the performance evaluation of the Electro-Optical (EO) imaging system. The Human vision contrast threshold characteristic for the triangle pattern is the premise for constructing the performance model based on the triangle orientation discrimination threshold. In this paper, a comprehensive test platform which integrates pattern generation, display control, measurement and analysis is constructed based on the 4AFC methodology used in the triangle orientation discrimination The discrimination probabilities of the triangle pattern with seven different spatial frequencies are measured at different background luminance levels. Futher, the Weibull function is fitted to the experiment data, and the curves of the human visual contrast threshold vs. the 75% correct discrimination probability are obtained. In the normal viewing luminance range, the results show that the contrast threshold increases with the increase of the target spatial frequency for the same background luminance, and the contrast threshold decreases with the increase of the background luminance for the same target spatial frequency.

Key words: contrast threshold, triangle pattern, Weibull function, 4-alternative forced choice