Interdigital Vc Holdings, Inc.

Thomson Licensing

Interdigital Ce Patent Holdings, Sas

Laurent Cauvin

Tania Pouli

Jonathan Kervec

Hassane Guermoud

David Touze

Christel Chamaret

Marie-Jean Colaitis

Ronan Boitard

Nicolas Caramelli

Guillaume Poirier

Robin Le Naour

A method comprising applying a conversion function to first RGB picture data in a color gamut and corresponding to a first non-linear domain to obtain second RGB picture data in the same color gamut in a linear domain, said conversion function being a combination () of a first and a second function, the first function being a linear function defined between zero and a second inflexion point the slope of which depending on a steepness value and the second function being a part of a linear to first non-linear domain transfer function defined from the second inflexion point, the second inflexion point being computed () in the first non-linear domain from a first inflexion point obtained () in the linear domain, the steepness value being computed () from the first and second inflexion points.

Method for limiting effects of quantization in a color gamut modification process applied to a video content

The present disclosure involves expanding the dynamic range of low dynamic range images and concerns obtaining a first expansion exponent map for an image, and determining, for each pixel of the image, an expanded luminance value by performing an exponentiation with an expansion exponent value determined from the first expansion exponent map on a luminance value of the pixel, and can include calculating, for the pixel of the image, an expansion correcting value by using a modulating function that takes as input a value representative of the luminance of the pixel and is an increasing function whose increase is higher for higher input values, and subtracting the expansion correcting value from the expansion exponent value of the first expansion exponent map.

Inverse tone mapping method and corresponding device

For the processing of an image with a tone-mapping function, it is known to select a tone-mapping function among a reference collection of reference tone-mapping functions and to apply the selected tone-mapping function to colors of this image. When applying this method to images of a video content, it is proposed to add, after such a selection for an image, a step of validation of this selection for the next images of video content. Advantage: prevent too frequent changes of tone-mapping function inside a video content, lower temporal instabilities and visual discomfort during visualization.

Tone-mapping of colors of a video content

The module () comprises: &#x2014;a low pass filter for low pass filtering luminance component of the image, &#x2014;a first look up table () storing precomputed values of a first expansion function of only low pass filtered luminance values, &#x2014;a second look up table () storing precomputed values of a second expansion function of only luminance values, &#x2014;a processor () configured to multiply an output of the second look up table corresponding to an input luminance value of a color to expand by an output of said first look up table corresponding to an input low pass filtered luminance value associated with said input luminance value.

Low cost color expansion module for expanding colors of an image

The disclosure relates generally to the field of high dynamic range (HDR) imaging and addresses the way of expanding the dynamic range of low dynamic range images. A method having the steps of obtaining expansion exponent map data for each one of a plurality of clusters of reference images, obtaining, for each cluster, one feature, called visual feature, representative of the luminance of reference images of the cluster, obtaining a visual feature for the image, comparing the visual feature of the image with the visual features of the clusters according to a distance criterion, selecting the cluster, the visual feature of which is the closest to the visual feature of the image, and applying an expansion exponent map defined by the expansion exponent map data of the selected cluster to the image is described.

An image processing method is described. The method includes obtaining low dynamic range expansion exponents E(p), obtaining target expansion exponents E(p) as a weighted sum of the high dynamic range expansion exponents E(p) and of the low dynamic range expansion exponents E(p), applying obtained target expansion exponent E(p) to low dynamic range luminance values Yof a low dynamic range version of the image, resulting in target luminance values Y, and building a tone-adapted version of said image based on said target luminance values Y.

Method for tone adapting an image to a target peak luminance Lof a target display device

Inverse tone mapping based on luminance zones is provided. A digital image can be obtained and luminance values of pixels of the digital image can be determined. One or more values of luminance zone boundaries can be determined. A zone expansion exponent map based on the luminance values and the one or more luminance zone boundaries can be determined. The one or more luminance zone boundaries divide the zone expansion exponent map into a plurality of luminance zones. The luminance values of the image can be inverse tone mapped based on the zone expansion exponent map. An expanded dynamic range image can be provided based on the inverse tone mapped luminance values.

Inverse tone mapping based on luminance zones

The present principles relate to a method and a device for reducing noise in a component of a picture. The method includes obtaining a low-pass filtered component by low-pass filtering the component of the picture, for a current pixel in the component of the picture. For at least one current neighboring pixel of the current pixel, computing a distance, relative to the current neighboring pixel, between the value of the current pixel in the low-pass filtered component and the value of the current neighboring pixel in the low-pass filtered component. When the distances relative to the at least one neighboring pixels of the current pixel are lower than a first threshold, modifying the value of the current pixel in said component of the picture according to a linear combination of the value of the current pixel in the component of the picture and the value of the current pixel in the low-pass filtered component. Otherwise the value of the current pixel in the at least one component of the picture remains unchanged.

Method and device for reducing noise in a component of a picture

A method is described for inverse tone mapping the luminance (Y(p)) of each pixel (p) of at least one image (I) of this sequence into an expanded luminance Y(p)=Y(p). Y(p), wherein E(p) is an expansion exponent value extracted from an expansion exponent map built from low pass motion-compensated temporal filtering of said image (I) and wherein Y(p) is a luminance-enhancement value extracted from a luminance-enhancement map built from high pass motion-compensated temporal filtering of said image (I).

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Chevaigne, France

Laurent Cauvin