Finding threshold contrasts for human observers when viewing noise-corrected LCDs

This paper presents results of psychophysical evaluations of an LCD with respect to its spatial noise. Spatial noise is quantified using a high-resolution CCD camera and compensated for using an error diffusion based algorithm. Psychophysical evaluation is performed in order to explore the dependence of human contrast sensitivity on display spatial noise. This evaluation uses the two-alternative forced choice (2-AFC) method . Gaussian-shaped objects, which simulate lung nodules, serve as stimuli. Three types of test images are used: Images containing simulated noise amounting to twice the amount of spatial noise present, images containing the original spatial noise and images compensated for the spatial noise. The probability of correct response and the detectability index, d', calculated indicates that spatial noise compensation leads to a lower contrast threshold.