Dolby Laboratories Licensing Corporation

Dolby International Ab

Dolby Laboratories Licensing Corproation

Jon Scott Miller

Robin Atkins

Scott J Daly

Mahdi Nezamabadi

Guan-Ming Su

Walter J Husak

Craig C Todd

Harshad Kadu

Kevin J Stec

Jerome D Shields

Christopher John Orlick

Lewis Ajax Johnson

Jan Froehlich

Yee Jin Lee

Kim Miller

Scott Daly

Richard W Webb

A handheld imaging device has a data receiver that is configured to receive reference encoded image data. The data includes reference code values, which are encoded by an external coding system. The reference code values represent reference gray levels, which are being selected using a reference grayscale display function that is based on perceptual non-linearity of human vision adapted at different light levels to spatial frequencies. The imaging device also has a data converter that is configured to access a code mapping between the reference code values and device-specific code values of the imaging device. The device-specific code values are configured to produce gray levels that are specific to the imaging device. Based on the code mapping, the data converter is configured to transcode the reference encoded image data into device-specific image data, which is encoded with the device-specific code values.

Perceptual luminance nonlinearity-based image data exchange across different display capabilities

A tone-mapping function that maps input images of a high dynamic range into reference tone-mapped images of a relatively narrow dynamic range is generated. A luma forward reshaping function is derived, based on first bit depths and second bit depths, for forward reshaping luma codewords of the input images into forward reshaped luma codewords of forward reshaped images approximating the reference tone-mapped images. A chroma forward reshaping mapping is derived for predicting chroma codewords of the forward reshaped images. Backward reshaping metadata that is to be used by recipient devices to generate a luma backward reshaping function and a chroma backward reshaping mapping is transmitted with the forward reshaped images to the recipient devices. Techniques for the joint derivation of forward luma and chroma reshaping functions are also presented.

Encoding and decoding reversible production-quality single-layer video signals

A content-adaptive quantizer processor receives an input image with an input bit depth. A noise-mask generation process is applied to the input image to generate a noise mask image which characterizes each pixel in the input image in terms of its perceptual relevance in masking quantization noise. A noise mask histogram is generated based on the input image and the noise mask image. A masking-noise level to bit-depth function is applied to the noise mask histogram to generate minimal bit depth values for each bin in the noise mask histogram. A codeword mapping function is generated based on the input bit depth, a target bit depth, and the minimal bit depth values. The codeword mapping function is applied to the input image to generate an output image in the target bit depth.

Content-adaptive perceptual quantizer for high dynamic range images

Methods to reduce chroma-related artifacts during video coding of high dynamic range images are presented. Given an input signal in a color space comprising a luma component and two chromaticity components, a processor determines the original white point chromaticity coordinates (Du, Dv) of a white point in the color space of the input signal. The input signal is translated using a chromaticity translation function to a second signal in a translated color space comprising two translated chromaticity components, wherein the chromaticity translation function shifts the original white point chromaticity coordinates to a predetermined second set of coordinates in the translated chromaticity color space. The second signal is encoded to generate a coded bit stream.

Chromaticity translations in coding of enhanced dynamic range signals

In some embodiments, an encoding method for generating an extended dynamic range (EDR) channel in response to an input video channel, such that the EDR channel's code values consist of code values in a range from a standard black level, X, through a standard white level, Z, and an additional code value set. The EDR channel is displayable with standard dynamic range and standard precision by a standard dynamic range video system which maps to the level, X, any of the EDR channel's values less than X, and maps to the level, Z, any of the EDR channel's values greater than Z, and is displayable with an extended dynamic range greater than the standard dynamic range and/or a precision greater than the standard precision by an EDR video system. Other aspects are systems configured to perform embodiments of the encoding method, and methods and systems for displaying EDR video.

Method and system for backward compatible, extended dynamic range encoding of video

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Harleysville, PA, United States of America

Jon Scott Miller