Visibility and annoyance of LCD defective sub-pixels of different colors for different surrounds and positions

In this study we investigate the visibility and annoyance of simulated defective sub-pixels in a liquid crystal display (LCD). The stimulus was a rectangular image containing one centered object with a gray surround and a single defective pixel. The surround was either uniform gray or a gray-level texture. The target was a simulated discolored pixel with one defective sub-pixel (green, red or blue) and two normally functioning sub-pixels. On each trial, it was presented at a random position. Subjects were asked to indicate if they saw a defective pixel, and if so, where it was located and how annoying it was. For uniform surrounds, our results show that detection probability falls slowly for green, faster for red, and fastest for blue as background luminance increases. When detection probability is plotted against luminance contrast green defective pixels are still most detectable, then red, then blue. Mean annoyance value falls faster than detection probability as background luminance increases, but the trends are the same. A textured surround greatly reduces the detection probability of all defective pixels. Still, green and red are more detectable than blue. With the textured surround the mean annoyance tends to remain high even when detection probability is quite low. For both types of surrounds, probability of detection is least for targets in the bottom region of the image.