Abstract: An image processing device and method for converting an input image having a first dynamic range into an output image having a second dynamic range higher than the first dynamic range are provided. The image processing device includes a mapping unit for transforming an input luminance value associated with a pixel of the input image into an output luminance value associated with the corresponding pixel in the output image. The mapping unit is configured to apply a continuous and increasing function mapping a first range of values into a second range of values, whereby the highest value in the first range of values is mapped by the continuous and increasing function into a supremum of the second range of values. The mapping unit is configured to adjust the supremum depending on a peak luminance.

Abstract: The invention concerns a method for converting an input image comprising an input luminance component made of elements into an output image comprising an output luminance component made of elements, the respective ranges of the output luminance component values and input luminance component element values being of different range extension. the method comprises for the input image: computing a value of a general variable representative of at least two input luminance component element values; transforming each input luminance component element value into a corresponding output luminance component element value according to the computed general variable value; and converting the input image using the determined output luminance component element values.

Abstract: 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.

Abstract: A lower dynamic range visual content (21) of a virtual reality or VR scene represented in a curved shape form is adapted to a higher dynamic range display of the virtual reality scene. At least two planar key views (230) of the VR scene area obtained at least two parameter values (240) respectively associated with those planar key views are obtained, corresponding to at least one parameter adapted to expand a dynamic range of a visual content, and a higher dynamic range visual content (22) corresponding to the lower dynamic range visual content in at least part of the VR scene extending beyond the planar key views is determined, based on the parameter values. Applications to Inverse Tone Mapping.

Abstract: The present disclosure relates to a method for providing assistance to a colorist in color grading of a virtual reality video content, called VR content. The method includes receiving the VR content being graded by a color grading station and receiving position information representative of the position of at least one hand of a colorist versus the color grading station. The method further includes generating, based on the position information, visual control information showing the position of the at least one hand of the colorist versus at least one grading control element of the color grading station and displaying the visual control information together with the graded VR content on a head mounted display carried by the colorist in order to help the colorist manipulating the at least one grading control element.

Abstract: 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.

Abstract: A lower dynamic range visual content (21) of a virtual reality or VR scene represented in a curved shape form is adapted to a higher dynamic range display of the virtual reality scene. At least two views planar key views (230) of the VR scene area obtained, at least two parameter values (240) respectively associated with those planar key views are obtained, corresponding to at least one parameter adapted to expand a dynamic range of a visual content, and a higher dynamic range visual content (22) corresponding to the lower dynamic range visual content in at least part of the VR scene extending beyond the planar key views is determined, based on the parameter values. Applications to Inverse Tone Mapping.

Abstract: A method is described for converting an input image into an output image, the output image including an output luminance component made of elements. The method includes: obtaining an input luminance component from the input image; determining the output luminance component, the respective ranges of the output luminance component element values and input luminance component element values being of different range extension, the determining step including: —determining a first intermediate luminance component from the input luminance component and an exponent, —obtaining a mapping profile allowing for mapping a luminance component based on the input luminance component into the output luminance component, —determining a second intermediate luminance component from the input luminance component and the obtained mapping profile, —determining the output luminance component from the first and second intermediate luminance components; and converting the input image into the output image.

Abstract: The present disclosure relates to a method for providing assistance to a colorist in color grading of a virtual reality video content, called VR content. The method includes receiving the VR content being graded by a color grading station and receiving position information representative of the position of at least one hand of a colorist versus the color grading station. The method further includes generating, based on the position information, visual control information showing the position of the at least one hand of the colorist versus at least one grading control element of the color grading station displaying the visual control information together with the graded VR content on a head mounted display carried by the colorist in order to help the colorist manipulating the at least one grading control element.

Abstract: 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.

Abstract: A method is described for converting an input image into an output image, the output image including an output luminance component made of elements. The method includes: obtaining an input luminance component from the input image; determining the output luminance component, the respective ranges of the output luminance component element values and input luminance component element values being of different range extension, the determining step including: —determining a first intermediate luminance component from the input luminance component and an exponent, —obtaining a mapping profile allowing for mapping a luminance component based on the input luminance component into the output luminance component, —determining a second intermediate luminance component from the input luminance component and the obtained mapping profile, —determining the output luminance component from the first and second intermediate luminance components; and converting the input image into the output image.

Abstract: 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.

Abstract: The module (700) comprises: —a low pass filter for low pass filtering luminance component of the image, —a first look up table (710) storing precomputed values of a first expansion function of only low pass filtered luminance values, —a second look up table (720) storing precomputed values of a second expansion function of only luminance values, —a processor (740, 760) 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.

Abstract: A lower dynamic range visual content (21) of a virtual reality or VR scene represented in a curved shape form is adapted to a higher dynamic range display of the virtual reality scene. At least two views planar key views (230) of the VR scene area obtained, at least two parameter values (240) respectively associated with those planar key views are obtained, corresponding to at least one parameter adapted to expand a dynamic range of a visual content, and a higher dynamic range visual content (22) corresponding to the lower dynamic range visual content in at least part of the VR scene extending beyond the planar key views is determined, based on the parameter values. Applications to Inverse Tone Mapping.

Abstract: A method for inverse tone mapping is provided. The method comprising obtaining a digital image in a color space wherein the luminance is separate from the chrominance, determining a base luminance of pixels in the digital image, determining a detail enhancement map, determining a pixel expansion exponent map, determining an edge map of the image, inverse tone mapping luminance of image based on edge map, pixel expansion map and base luminance, and providing an expanded dynamic range image based on the inverse tone mapped luminance.

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

Abstract: 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.

Abstract: A method and device for processing LDR images of a video sequence to improve image quality. The method comprises temporally decomposing successive HDR frames of a video sequence and the corresponding LDR frames and performing a comparison between the HDR and LDR frequency sub-bands. A current LDR image can then be modified on the basis of a comparison between the frequency sub-bands.

Abstract: The module (700) comprises:—a low pass filter for low pass filtering luminance component of the image,—a first look up table (710) storing precomputed values of a first expansion function of only low pass filtered luminance values,—a second look up table (720) storing precomputed values of a second expansion function of only luminance values,—a processor (740, 760) 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.

Abstract: Systems and methods of re-coloring digital images are disclosed. A system including a processor and a memory can execute stored instructions to obtain luminance information of a first image, e.g., an original grayscale image, and obtain color information of a second image, e.g., a colorized image of the original grayscale image. Multiple segmented image regions can be determined based on the luminance information of the first image. A color seed for each segmented image region can be determined based on the color information of the second image. A third image, e.g., a re-colored image, can be determined based on diffusing the color seeds of the segmented image regions.