Dolby Laboratories Licensing Corporation

Robert Wanat

Robin Atkins

Jaclyn Anne Pytlarz

Scott J Daly

Jon S McElvain

Anustup Kumar Atanu Choudhury

David Brooks

Methods and systems for generating an image quality metric are described. A reference and a test image are first converted to the ITP color space. After calculating difference images &#x394;I, &#x394;T, and &#x394;P, using the color channels of the two images, the difference images are convolved with low pass filters, one for the I channel and one for the chroma channels (I or P). The image quality metric is computed as a function of the sum of squares of filtered &#x394;I, &#x394;T, and &#x394;P values. The chroma low-pass filter is designed to maximize matching the image quality metric with subjective results.

Image quality metric for HDR images and video

In a method for dithering image data, a processor receives an input image in a first color space and a first bit depth larger than 8 bits. The processor converts the input image into a first image in a perceptually uniform color space, such as the BT. 2100 ICtCp color space, with pixel values scaled to be within a target bit depth, it quantizes the first image to generate a quantized image, it generates an error image between the first image and the quantized image, and using a random threshold, it generates a dithered image based on the random threshold, the error image, and the quantized image, allowing to reduce the bit-depth representation for visually consistent reproduction by two bits.

Perceptual dithering for HDR video and images

Input scene images are captured from an original scene. The input scene images may be represented in an input color space. The input scene images are converted into color-space-converted scene images in one of an LMS color space, an ICtCp color space, etc. Scene light levels represented in the color-space-converted scene images are mapped, based at least in part on an optical transfer function, to mapped light levels. A tone mapping is applied to the mapped light levels to generate corresponding display light levels to be represented in display images. The display images may be rendered on a target display.

Perceptually preserving scene-referred contrasts and chromaticities

Methods are disclosed for adaptive display management using one or more viewing environment parameters. Given the one or more viewing environment parameters, an effective luminance range for a target display, and an input image, a tone-mapped image is generated based on a tone-mapping curve, an original PQ luminance mapping function, and the effective luminance range of the display. A corrected PQ (PQ') luminance mapping function is generated according to the viewing environment parameters. A PQ-to-PQ&#x2032; mapping is generated, wherein codewords in the original PQ luminance mapping function are mapped to codewords in the corrected (PQ&#x2032;) luminance mapping function, and an adjusted tone-mapped image is generated based on the PQ-to-PQ&#x2032; mapping.

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Sunnyvale, CA, United States of America

Robert Wanat