Dolby Laboratories Licensing Corporation

Dolby Laboratories Corporation

Dobly Laboratories Licensing Corporation

Jaclyn Anne Pytlarz

Robin Atkins

Peng Yin

Taoran Lu

Elizabeth G Pieri

Robert Wanat

Jake William Zuena

Scott J Daly

Timo Kunkel

Tao Chen

Samir N Hulyalkar

Jon S McElvain

Craig C Todd

Alexandre Chapiro

Gopi Lakshminarayanan

David Brooks

Anustup Kumar Atanu Choudhury

Jon Scott Mcelvain

Hariharan Ganapathy Kathirvelu

Per Jonas A Klittmark

A video delivery system for luminance adjustment based upon a viewer adaptation state comprises a processor configured to: receive a source image including a current image frame including metadata corresponding to a mean luminance value of the current image frame, and the source image including an upcoming image frame including metadata corresponding to a mean luminance value of the upcoming image frame. The processor is configured to determine an ambient luminance value based on an ambient luminance, determine an incident luminance value based on the ambient luminance value and the mean luminance value, determine a difference between a current pupil size and a target pupil size, and generate an output image by modifying the source image based on a luminance adjustment factor, the luminance adjustment factor being a function of the difference between the current pupil size and the target pupil size.

Luminance adjustment based on viewer adaptation state

In a method to improve backwards compatibility when decoding high-dynamic range images coded in a wide color gamut (WCG) space which may not be compatible with legacy color spaces, hue and/or saturation values of images in an image database are computed for both a legacy color space (say, YCbCr-gamma) and a preferred WCG color space (say, IPT-PQ). Based on a cost function, a reshaped color space is computed so that the distance between the hue values in the legacy color space and rotated hue values in the preferred color space is minimized. HDR images are coded in the reshaped color space. Legacy devices can still decode standard dynamic range images assuming they are coded in the legacy color space, while updated devices can use color reshaping information to decode HDR images in the preferred color space at full dynamic range.

Signal reshaping for high dynamic range signals

In a method to improve backwards compatibility when decoding high-dynamic range images coded in a wide color gamut (WCG) space which may not be compatible with legacy color spaces, hue and/or saturation values of images in an image database are computed for both a legacy color space (say, YCbCr-gamma) and a preferred WCG color space (say, IPT-PQ). Based on a cost function, a reshaped color space is computed so that the distance between the hue values in the legacy color space and rotated hue values in the preferred color space is minimized HDR images are coded in the reshaped color space. Legacy devices can still decode standard dynamic range images assuming they are coded in the legacy color space, while updated devices can use color reshaping information to decode HDR images in the preferred color space at full dynamic range.

Methods and systems to adjust differently brightness and contrast for dark and bright pictures on a display are provided. Given a tone-mapping curve mapping an input dynamic range to a display comprising a minimum and maximum display luminance value, the maximum display luminance value is lowered to an adjusted luminance value according to user defined parameters. The input dynamic range is tone-mapped to the display dynamic range using the adjusted luminance value. For brightness control, the tone mapped image is stretched linearly back to the maximum display luminance value. For contrast control, a gamma or power EOTF of the display is adjusted according to the adjusted luminance. For displays with global backlight control, the global backlight is adjusted only when contrast is adjusted.

Image-dependent contrast and brightness control for HDR displays

Two corresponding color patches are displayed on two image displays until adjusted by a viewer to match visually to a common color. Two sets of code values rendered on the two corresponding color patches on the two image displays are identified. Two sets of tristimulus values for the viewer are determined based on the two sets of code values rendered on the two corresponding color patches on the two image displays. The viewer's color matching function are generated based on the two sets of tristimulus values. The viewer's CMF is used in image rendering operations on a target image display.

Metameric stabilization via custom viewer color matching function

Novel methods and systems for compensating for ambient light around displays are disclosed. A shift in the PQ curve applied to an image can compensate for sub-optimal ambient light conditions for a display, with the PQ shift being either an addition to a compensation value in PQ space followed by a subtraction of the compensation value in linear space, or an addition to the compensation value in linear space followed by a subtraction of the compensation value in PQ space. Further adjustments to the PQ curve can also be made to provide an improved image quality with respect to image luminance.

Systems and methods for ambient light compensation using PQ shift

Methods and systems for chromatic ambient-light support are provided. Given an input surround correlated color temperature (CCT), its normalized value is mapped to a preferred gray CCT value using a sigmoid-like function model generated based on viewer experimental data. The preferred gray CCT value is then mapped to an adjusted CCT value so that viewing conditions on a display with the input surround CCT value match a D65 surround CCT value.

Chromatic ambient light correction

Methods and systems for the display management of HDR video signals are presented. The mapping is based on tone mapping and color volume mapping which map an input signal with an input dynamic range and color volume to a target display with a target dynamic range and color volume. Both a global tone-mapping and precision-mapping methods using pyramid filtering are presented.

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Sunnyvale, CA, United States of America

Jaclyn Anne Pytlarz