A Visual Model for Very Wide-Gamut HDR Displays That Accounts for the Helmholtz–Kohlrausch Effect

We have developed a computational model and a test model for predicting the brightness, a visual perception term, achieved by high-dynamic-range (HDR) televisions and computer monitors, in particular, those with materials that feature primary colors having high spectral purity. Quantum dot materials in combination with emissive pixel lighting is expanding the color gamut level to attain a degree of performance unmatched in today’s consumer and professional displays. These displays exhibit highly significant improvements in colorfulness and brightness owing to their narrowband primaries and to the Helmholtz–Kohlrausch (H–K) effect, where colors—notably reds and blues—are perceived as far brighter than their reference white. We blended the iCAM06 computational model originally designed for HDR image evaluation with an improved treatment of vivid colors. Our data collection relied on a rare, yet commercially available 2D spectroradiometer that captures up to 1.4 million samples of spectral data across any image, an achievement impossible to attain manually. Our approach coupled nicely with the filter image-processing steps in iCAM06. Finally, we extracted image brightness for white, red, and blue for determining the SEMI perceptual contrast length (PCL) to assess the predicted improvement level of our model and then matched those results to subjective experiments. As a result, we have a methodology that can be used by display makers to measure and predict brightness as a function of colorfulness to optimize luminance—notably for reducing power—in displays with spectrally pure primaries
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