The Reaction Time of Color Adaptation for Screen Background below the Threshold of Texture Legibility

  • 曾 朝源

Student thesis: Doctoral Thesis

Abstract

This study explored under two different illumination conditions (normal daylight at D65 and low illumination) how chromatic adaptation affected the legibility texture recognition of background threshold and then found the color threshold or texture that would not affect each other for those with color vision deficiency (CVD) and those who had normal color vision (NCV) The study mainly used the basic screen colors such as red green cyan and yellow and the Landolt ring system associated with vision measurement and formed them into experiment stimulus with different sizes and spacing while adopting the psychophysical approach to carry out the related experiment There were two preliminary experiments In one of them we found the red visual thresholds and visible pattern sizes for the 10 test subjects (5 participants with color vision deficiency or CVD and 5 with normal color vision or NCV) and they were CVD: RGB(234 0 21) and NCV: RGB(223 0 32) while the size for the texture pattern was 2 5' (0 436mm) and the pitch or spacing was 2 5' (0 436mm) In the experiment for legibility performance the red green cyan and yellow backgrounds were tested with changes in the gap size of Landolt ring and it was learned that when the gap value was 3 33' (0 678mm) the difference in the stimulus color would be more significant We compiled the results from the two preliminary experiments and organized another two new experiments for the legibility of texture threshold with 20 people in the NCV group (10 men and 10 women) For the new experiment I there were four compositions of stimulus with texture threshold (background color - Landolt ring color) and they were Type 1: RGB(255 0 0) - RGB(234 0 21) Type 2: RGB(255 0 0) - RGB(223 0 32) Type 3: RGB(234 0 21) - RGB(255 0 0) and Type 4: RGB(223 0 32) - RGB(255 0 0) For experiment II there were six compositions of stimulus with texture threshold (texture dot - background color - Landolt ring color) and they were Type 1: RGB(234 0 21) - RGB(223 0 32) - RGB(255 0 0) Type 2: RGB(223 0 32) - RGB(234 0 21) - RGB(255 0 0) Type 3: RGB(223 0 32) - RGB(255 0 0) - RGB(234 0 21) Type 4: RGB(255 0 0) - RGB(223 0 32) - RGB(234 0 21) Type 5: RGB(234 0 21) - RGB(255 0 0) - RGB(223 0 32) and Type 6: RGB(255 0 0) - RGB(234 0 21) - RGB(223 0 32) The results of the study showed that (I) In terms of the legibility of red threshold of CVD and NCV applied to Landolt ring NCV's threshold at RGB(223 0 32) was significant (II) With the proper configuration of size and spacing for textured patterns and Landolt ring the total mean response time for legibility in a low illumination environment is better than that of the D65 environment We used the red thresholds of NCV and CVD separately as the background color texture dot and Landolt ring color and learned that RGB(234 0 21) as Landolt ring offered the most errors while RGB(234 0 21) as the texture dot offered the least errors (III) As for the mean response time of legibility after chromatic adaptation Type 5 stimulus combination (texture dot: RGB(234 0 21) background color: RGB(255 0 0) Landolt ring color: RGB(223 0 32) after yellow adaptation provided the best visual acuity in D65 environment and low illumination environment As for the legibility of textured stimulus the response times after red color adaptation were ranked at Type 1 Type 5 Type 2 > Type 3 Type 6 > Type 4 As for the cases after green color adaptation the order was ranked at Type 1 Type 5 > Type 2 Type 4 > Type 3 Type 6 For the cyan color adaptation the order was Type 1 Type 5 > Type 2 Type 3 Type 4 > Type 6 For the yellow color adaptation the order was Type 1 Type 5 > Type 2 Type 4 > Type 3 Type 6 Based on the results of this study it is recommended to use the following color combinations when red is chosen as part of the composition: for stimulus with just the red threshold the combination is having the texts and patterns at RGB(223 0 32) and background color RGB(255 0 0) For stimulus with texture the texture dot RGB(234 0 21) background color RGB(255 0 0) and the texts or patters for the stimulus is RGB(223 0 32) These can improve the legibility of colored pattern for CVD without affecting NCV so that both CVD and NCV can obtain the correct legibility results while the legibility is not affected
Date of Award2017 Jul 27
Original languageEnglish
SupervisorFong-Gong Wu (Supervisor)

Cite this

The Reaction Time of Color Adaptation for Screen Background below the Threshold of Texture Legibility
朝源, 曾. (Author). 2017 Jul 27

Student thesis: Doctoral Thesis