| dc.description.abstract | A psychophysical experiment was conducted to investigate the effect of surround luminance i.e. luminance out of 10 degrees visual angle of the retina, on luminance contrast in foveal view by the human visual system (HVS) on a high dynamic range (HDR) display having a maximum 1000 cd/m2 luminance. The stimulus modified Landolt C was presented on display at a visual angle of 2 degrees, with the observer positioned 40 cm away from the display, whereas a dark black circle with minimum luminance (0.03 cd/m2) was employed within a visual angle of 10 degrees on display as background, and the display’s rest of pixel area as a surrounding. The experiment employed multiple luminance scales of the surrounding, encompassing both achromatic color and chromatic colors such as red, green, blue, yellow, cyan, and magenta. The experiment involved a total of thirty participants, 19 males and 11 females, who were tasked with recognizing the orientation of stimulus openings to determine the luminance thresholds of their vision in various surrounding colors using a threshold and matching method based psychophysical experiment, specifically focusing on luminance adaptation.
The experiment’s findings showed that red surround color had the most impact on luminance adaption compared to all other surround colors, whereas blue and yellow surround color has the least impact. It was discovered that observers had the lowest consistency in the red surround color, they required the highest number of stimuli to attain a particular threshold, and they spent the most time on red surround based stimuli overall, indicating that it was challenging for observers to discern contrast in the red surround color. Contrarily, blue showed more consistent responses from observers, required the fewest stimuli to reach the threshold, and required the least overall time to process stimuli, indicating that it was not difficult to notice the contrast threshold in the blue surrounding color. Additionally, it was observed that, with the exception of white, blue, and yellow surround colors, the longer time an observer spent in a certain surround color, the more luminance
adapted it became to that surround color. Moreover, this experiment also produced byproduct results like vertical and horizontal perception, and it was discovered that HVS perceive vertical direction gratings better than horizontal ones. These results can be valuable to design or evaluate the color appearance models. The Matlab code used for this experiment is uploaded on GitHub https://github.com/akash-harijan/LuminanceAdaptation. | |
