scholarly journals Luminance and chromatic contrast sensitivity at high light levels

2019 ◽  
Vol 19 (10) ◽  
pp. 70b ◽  
Author(s):  
Sophie Wuerger ◽  
Rafal Mantiuk ◽  
Maria Perez-Ortiz ◽  
Jasna Martinovic
Keyword(s):  
Contrast Sensitivity ◽  
High Light ◽  
Chromatic Contrast ◽  
Light Levels ◽  
Chromatic Contrast Sensitivity

scholarly journals Spatio-chromatic contrast sensitivity under mesopic and photopic light levels

2020 ◽  
Vol 20 (4) ◽  
pp. 23
Author(s):  
Sophie Wuerger ◽  
Maliha Ashraf ◽  
Minjung Kim ◽  
Jasna Martinovic ◽  
María Pérez-Ortiz ◽  
...  
Keyword(s):  
Contrast Sensitivity ◽  
Chromatic Contrast ◽  
Light Levels ◽  
Chromatic Contrast Sensitivity

Investigation of Chromatic Contrast Sensitivity Based on Different Color Directions and Spatial Frequencies

2011 ◽  
Vol 31 (1) ◽  
pp. 0133002 ◽  
Author(s):  
吕玮阁 Lü Weige ◽  
徐海松 Xu Haisong ◽  
汪哲弘 Wang Zhehong ◽  
M. Ronnier Luo M. Ronnier Luo
Keyword(s):  
Contrast Sensitivity ◽  
Chromatic Contrast ◽  
Spatial Frequencies ◽  
Different Color ◽  
Chromatic Contrast Sensitivity

Spatial Integration of Objectively Equiluminous Chromatic Gratings

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 200-200
Author(s):  
M I Kankaanpää ◽  
J Rovamo ◽  
H T Kukkonen ◽  
J Hallikainen
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Spatial Integration ◽  
Chromatic Contrast ◽  
Shape Difference ◽  
Sensitivity Functions ◽  
Spatial Frequencies ◽  
Low Pass ◽  
Chromatic Aberrations ◽  
Chromatic Contrast Sensitivity

Contrast sensitivity functions for achromatic and chromatic gratings tend to be band-pass and low-pass in shape, respectively. Our aim was to test whether spatial integration contributes to the shape difference found at low spatial frequencies. We measured binocular chromatic contrast sensitivity as a function of grating area for objectively equiluminous red - green and blue - yellow chromatic gratings. Chromatic contrast refers to the Michelson contrast of either of the two chromatic component gratings presented in counterphase against the combined background. Grating area ( A) varied from 1 to 256 square cycles ( Af2) at spatial frequencies ( f) of 0.125 – 4.0 cycles deg−1. We used only horizontal gratings at low and medium spatial frequencies to minimise the transverse and longitudinal chromatic aberrations due to ocular optics. At all spatial frequencies studied, chromatic contrast sensitivity increased with grating area. Ac was found to be constant at low spatial frequencies (0.125 – 0.5 cycles deg−1) but decreased in inverse proportion to increasing spatial frequency at 1 – 4 cycles deg−1. Thus, spatial integration depends similarly on spatial frequency for achromatic (Luntinen et al, 1995 Vision Research35 2339 – 2346) and chromatic gratings, and differences in spatial integration do not contribute to the shape difference of the respective contrast sensitivity functions.

scholarly journals Spatio-chromatic contrast sensitivity across the life span: interactions between age and light level in high dynamic range

2020 ◽  
Vol 20 (11) ◽  
pp. 1286
Author(s):  
Maliha Ashraf ◽  
Sophie Wuerger ◽  
Minjung Kim ◽  
Helen Saunderson ◽  
Jasna Martinovic ◽  
...  
Keyword(s):  
Life Span ◽  
Contrast Sensitivity ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Light Level ◽  
Chromatic Contrast ◽  
High Dynamic ◽  
Chromatic Contrast Sensitivity

scholarly journals Are Spatial Chromatic Contrast Sensitivity Band-pass or Lowpass Functions?

2020 ◽  
Vol 2020 (28) ◽  
pp. 125-129
Author(s):  
Qiang Xu ◽  
Stephen Westland ◽  
Marcel Lucassen ◽  
Dragan Sekulovski ◽  
Sophie Wuerger ◽  
...  
Keyword(s):  
Contrast Sensitivity ◽  
Threshold Method ◽  
Colour Difference ◽  
Chromatic Contrast ◽  
Experimental Conditions ◽  
Colour Centres ◽  
Spatial Frequencies ◽  
Wide Range ◽  
Band Pass ◽  
Chromatic Contrast Sensitivity

The goal of this research is to generate high quality chromatic Contrast Sensitivity Function (CSF) over a wide range of spatial frequencies from 0.06 to 3.84 cycles per degree (cpd) surrounding 5 CIE proposed colour centres (white, red, yellow, green and blue) to study colour difference. At each centre, 6 colour directions at each of 7 frequencies were sampled, from 0.06 to 3.84 cycles per degree (cpd) corresponding to the number of cycles: from 2.3 to 144.4 respectively. A threshold method based on forced-choice stair-case was adopted to investigate the just noticeable (threshold) colour difference. The results revealed that the chromatic CSF under the present experimental conditions having many lower spatial frequencies covering five colour centres to be band pass, whereas previous results indicated it was low pass. However, this could be caused by the present experimental conditions such as fixed-size stimuli and constant luminance. The new chromatic CSF for R-G and Y-B channels were also developed.

scholarly journals Longitudinal measurements of luminance and chromatic contrast sensitivity: comparison between wavefront-guided LASIK and contralateral PRK for myopia

2013 ◽  
Vol 76 (5) ◽  
pp. 270-273 ◽  
Author(s):  
Mirella Telles Salgueiro Barboni ◽  
Claudia Feitosa-Santana ◽  
Jackson Barreto Junior ◽  
Marcos Lago ◽  
Samir Jacob Bechara ◽  
...  
Keyword(s):  
Contrast Sensitivity ◽  
Chromatic Contrast ◽  
Longitudinal Measurements ◽  
Chromatic Contrast Sensitivity
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