Viewer preference statistics for shadow, diffuse, specular, and emissive luminance of high dynamic range displays
Scott Daly & Timo Kunkel
(Dolby Laboratories)
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Description:
A subjective study was performed to find minimum and maximum display luminances based on viewer preferences. The motivation was to find values based on real-world structured image content, as opposed to geometric test patterns commonly used in the literature, and to find values relevant for display of video content. The test images were specifically designed, both in scene set-up and in capture techniques (i.e., HDR multiple exposure merging), to test these limits without the usual perceptual conflicts of contrast induction, the Stevens effect, the Hunt effect, contrast/sharpness interactions. The display was designed to render imagery at extreme ranges of luminance and high contrast to avoid the usual elevation of black level with increasing brightness, ranging from 0.004 to 20,000 cd/m2. The image signals were captured, represented, and processed to avoid the common unintended signal distortions of clipping, contrast reduction, and tonescale shape changes. The image range was broken into diffuse reflective and highlight regions. Preferences were studied as opposed to detection thresholds, to provide results more directly relevant to viewers of media. Statistics of the preferences will be described, as opposed to solely reporting mean and standard deviation values. As a result, we believe these results are robust to future hardware capabilities in displays.
Created: Wednesday, November 28th, 2012