An Experimental Method to Determine Quantization Levels for High Luminance Patterns

The quantization levels, which forms an important basis for video coding, are mainly determined for 8-bit image representation and for low dynamic range (LDR) typical displays with a luminance level of 100-500 cd/ m
²
. The quantization levels have not been studied until now for high luminance patterns and high dynamic range (HDR) displays, which can reach up to 4000 cd/m
²
. In this study, an HDR display based perceptual experimental method is proposed in order to determine just noticeable quantization levels for discrete cosine transform (DCT) coefficients on high luminance images. The proposed method first render the quantization noise patterns for different DCT frequencies at different mean luminance levels on HDR display by estimating the pixel values of LED and LCD layers of the display. Then, the quantization levels are determined by a geometric search based two alternative forced choice procedure, which randomly presents the luminance patterns with and without quantization noise at different amplitudes to the subjects at different intervals. The first results are obtained for 30 DCT frequencies with a mean luminance of 1000 cd/m
²
over 3 subjects and discussed with respect to frequency changes.