Visibility of small luminance perturbations in television displays

Measurements of the visibility of small-magnitude luminance perturbations at various parts of the grey scale have been made using television displays. The purpose was to establish whether the measurements made by many workers using optical apparatus could be applied to a television screen used in normal viewing conditions. It was found that, in general, close agreement was obtained. However, the visibility of random noise added to a television picture was found to be appreciably different from that of more coherent luminance changes. The visibility of the noise as a function of the luminance of that part of the display being observed is greatly affected by the different retentivity of the human optical system at different values of luminance. It was observed that noise variations are relatively less visible in dark areas of the picture than in bright areas.