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Effect of chromatic mechanisms on the detection of mesopic incremental targets at different eccentricities

Khanh, Tran Quoc and Bodrogi, Peter Zsolt and Haferkemper, Nils and Schiller, Christoph and Vas, Zoltan and Varady, Geza and Schanda, Janos (2010):
Effect of chromatic mechanisms on the detection of mesopic incremental targets at different eccentricities.
In: Licht 2010, Wien, 17. Oktober 2010, 2010, [Conference or Workshop Item]

Abstract

Spectral sensitivity functions for the threshold detection of mesopic incremental targets were compared for different target eccentricities (10, 20, and 30�) and for different mesopic backgrounds (0.1, 0.5 and 1.0 cd m)2). Relative responsivities of achromatic mechanisms (L + M and rods) and chromatic mechanisms (S and |L–M|) were estimated for each eccentricity and background. Chromatic mechanisms contribute significantly to detection but their effect is lower at 30�. A new contrast metric (CCHC2) is introduced to account for the selective adaptation of the photoreceptors and the effects of the chromatic mechanisms i.e. broadening of the range of spectral sensitivity with multiple local maxima and yellow sub-additivity of detection performance. The CCHC2 metric is compared with the achromatic contrast metric of the MOVE model (CMOVE). For the same target, CCHC2 generally predicts a higher visibility level than CMOVE. However, in accordance with visual observations, for grey or yellowish incremental targets appearing at the eccentricities of 20 and 30�, the visibility predicted by CCHC2 is less than the visibility predicted by CMOVE.

Item Type: Conference or Workshop Item
Erschienen: 2010
Creators: Khanh, Tran Quoc and Bodrogi, Peter Zsolt and Haferkemper, Nils and Schiller, Christoph and Vas, Zoltan and Varady, Geza and Schanda, Janos
Title: Effect of chromatic mechanisms on the detection of mesopic incremental targets at different eccentricities
Language: English
Abstract:

Spectral sensitivity functions for the threshold detection of mesopic incremental targets were compared for different target eccentricities (10, 20, and 30�) and for different mesopic backgrounds (0.1, 0.5 and 1.0 cd m)2). Relative responsivities of achromatic mechanisms (L + M and rods) and chromatic mechanisms (S and |L–M|) were estimated for each eccentricity and background. Chromatic mechanisms contribute significantly to detection but their effect is lower at 30�. A new contrast metric (CCHC2) is introduced to account for the selective adaptation of the photoreceptors and the effects of the chromatic mechanisms i.e. broadening of the range of spectral sensitivity with multiple local maxima and yellow sub-additivity of detection performance. The CCHC2 metric is compared with the achromatic contrast metric of the MOVE model (CMOVE). For the same target, CCHC2 generally predicts a higher visibility level than CMOVE. However, in accordance with visual observations, for grey or yellowish incremental targets appearing at the eccentricities of 20 and 30�, the visibility predicted by CCHC2 is less than the visibility predicted by CMOVE.

Journal or Publication Title: Ophthalmic and physiological optics, The journal of the college of optometrists
Volume: 2010
Number: 30
Divisions: 18 Department of Electrical Engineering and Information Technology > Institute for Electromechanical Design > Light Technology
18 Department of Electrical Engineering and Information Technology > Institute for Electromechanical Design
18 Department of Electrical Engineering and Information Technology
Event Title: Licht 2010
Event Location: Wien
Event Dates: 17. Oktober 2010
Date Deposited: 29 Oct 2010 09:58
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