Abstract: 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.

Abstract: Methods and systems are described for processing an image captured with an image sensor, such as a camera. In one embodiment, an estimated ambient light level of the captured image is determined and used to compute an optical-optical transfer function (OOTF) that is used to correct the image to preserve an apparent contrast of the image under the estimated ambient light level in a viewing environment. The estimated ambient light level is determined by scaling pixel values from the image sensor using a function that includes exposure parameters and a camera specific parameter derived from a camera calibration.

Abstract: 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.

Abstract: 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.

Abstract: An auto exposure method for a spatially-multiplexed-exposure (SME) high-dynamic-range (HDR) image sensor includes (a) retrieving raw image data from an exposure of the spatially-multiplexed-exposure high-dynamic-range image sensor, (b) preprocessing long-exposure pixel values and short-exposure pixel values of the raw image data to remove therefrom long-exposure pixel values and short-exposure pixel values failing to meet one or more quality requirements, (c) synthesizing, into an high-dynamic-range histogram, the long-exposure pixel values remaining after the step of preprocessing and the short-exposure pixel values remaining after the step of preprocessing, (d) deriving a goodness metric from the high-dynamic-range histogram, (e) adjusting at least one of the long exposure time and the short exposure time, based at least in part upon the goodness metric, and (f) outputting the at least one of the long exposure time and the short exposure time, as adjusted, to the spatially-multiplexed-exposure high-dynamic-

Abstract: Methods for recovering saturated pixel values in raw pixel data are described. Given an image with raw pixel values captured using sensors with a color filter array (CFA), image regions are classified according to how many color channels of the CFA are saturated. Values of saturated pixels are estimated based on weighted color ratios of unsaturated pixels and recovered pixels. Example methods for a Bayer CFA are provided.

Abstract: Methods and systems for frame rate scalability are described. Support is provided for input and output video sequences with variable frame rate and variable shutter angle across scenes, or for input video sequences with fixed input frame rate and input shutter angle, but allowing a decoder to generate a video output at a different output frame rate and shutter angle than the corresponding input values. Techniques allowing a decoder to decode more computationally-efficiently a specific backward compatible target frame rate and shutter angle among those allowed are also presented.

Abstract: 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.

Abstract: Methods for encoding and decoding high-dynamic range signals are presented. The signals are encoded in a high frame rate and are accompanied by frame-rate conversion metadata defining a preferred set of frame-rate down-conversion parameters, which are determined according to the maximum luminance of a target display, display playback priority modes, or judder control modes. A decoder uses the frame-rate conversion metadata to apply frame-rate down-conversion to the input high-frame-rate signal according to at least the maximum luminance of the target display and/or the characteristics of the signal itself. Frame-based and pixel-based frame-rate conversions, and judder models for judder control via metadata are also discussed.

Abstract: An existing metadata set that is specific to a color volume transformation model is transformed to a metadata set that is specific to a distinctly different color volume transformation model. For example, source content metadata for a first color volume transformation model is received. This source metadata determines a specific color volume transformation, such as a sigmoidal tone map curve. The specific color volume transformation is mapped to a color volume transformation of a second color volume transformation model, e.g., a Bézier tone map curve. Mapping can be a best fit curve, or a reasonable approximation. Mapping results in metadata values used for the second color volume transformation model (e.g., one or more Bézier curve knee points and anchors). Thus, devices configured for the second color volume transformation model can reasonably render source content according to received source content metadata of the first color volume transformation model.

Abstract: Methods and systems for frame rate scalability are described. Support is provided for input and output video sequences with variable frame rate and variable shutter angle across scenes, or for input video sequences with fixed input frame rate and input shutter angle, but allowing a decoder to generate a video output at a different output frame rate and shutter angle than the corresponding input values. Techniques allowing a decoder to decode more computationally-efficiently a specific backward compatible target frame rate and shutter angle among those allowed are also presented.

Abstract: Motion characteristics related to foreground objects and background regions bordering the foreground objects in images are determined. A frame rate conversion (FRC)-related metadata portion is generated based on the motion characteristics. The FRC-related metadata portion is to be used for determining an optimal FRC operational mode with a downstream device for the images. The images are encoded into a video stream. The FRC-related metadata portion is encoded into the video stream as a part of image metadata. The video stream is caused to be transmitted to the downstream device.

Abstract: Methods and systems for gamut mapping are disclosed. Pixels of an image or points of a look-up-table can be gamut mapped in a multi-step iterative process, by generating a coarse gamut hull and calculating a value of a distance metric for out-of-gamut pixels or LUT points, and subsequently generating a fine gamut hull in the neighborhood of the coarse gamut hull points closest to the out-of-gamut pixel or LUT points under consideration. The out-of-gamut pixel or LUT point is gamut mapped based on the smallest distance metric value calculated.

Abstract: In one embodiment, a dual modulator display systems and methods for rendering target image data upon the dual modulator display system are disclosed where the display system receives target image data, possible HDR image data and first calculates display control signals and then calculates backlight control signals from the display control signals. This order of calculating display signals and then backlight control signals later as a function of the display systems may tend to reduce clipping artifacts. In other embodiments, it is possible to split the input target HDR image data into a base layer and a detail layer, wherein the base layer is the low spatial resolution image data that may be utilized as for backlight illumination data. The detail layer is higher spatial resolution image data that may be utilized for display control data.

Abstract: 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.

Abstract: A method for generating metadata for use by a video decoder for displaying video content encoded by a video encoder includes: (1) accessing a target tone mapping curve; (2) accessing a decoder tone curve corresponding to a tone curve used by the video decoder for tone mapping the video content; (3) generating a plurality of parameters of a trim-pass function used by the video decoder to apply after applying the decoder tone curve to the video content, wherein the parameters of the trim-pass function are generated to approximate the target tone curve with the combination of the trim-pass function and the decoder tone curve, and (4) generating the metadata for use by the video decoder, including said plurality of parameters of the trim-pass function.

Abstract: Methods are disclosed for ambient light-adaptive display management. Given an input image, image metadata, an ambient-light signal, and parameters characterizing a target display, a processor generates an ambient-light adjustment function which maps input luminance values in a reference viewing environment to output luminance values in a target viewing environment, wherein the target viewing environment is determined based on the ambient-light signal. The ambient-light adjustment function is applied to the input image and the input metadata to generate a virtual image and new metadata. A tone-mapping function based on the new metadata and target display parameters is applied to the virtual image to generate an output image. The parameters for the target display are computed based on the ambient-light signal, global dimming metadata, and the luminance characteristics of the target display.

Abstract: In one embodiment, a dual modulator display systems and methods for rendering target image data upon the dual modulator display system are disclosed where the display system receives target image data, possible HDR image data and first calculates display control signals and then calculates backlight control signals from the display control signals. This order of calculating display signals and then backlight control signals later as a function of the display systems may tend to reduce clipping artifacts. In other embodiments, it is possible to split the input target HDR image data into a base layer and a detail layer, wherein the base layer is the low spatial resolution image data that may be utilized as for backlight illumination data. The detail layer is higher spatial resolution image data that may be utilized for display control data.

Abstract: Methods and systems for frame rate scalability are described. Support is provided for input and output video sequences with variable frame rate and variable shutter angle across scenes, or for input video sequences with fixed input frame rate and input shutter angle, but allowing a decoder to generate a video output at a different output frame rate and shutter angle than the corresponding input values. Techniques allowing a decoder to decode more computationally-efficiently a specific backward compatible target frame rate and shutter angle among those allowed are also presented.

Abstract: Methods and systems for gamut mapping are disclosed. Pixels of an image or points of a look-up-table can be gamut mapped in a multi-step iterative process, by generating a coarse gamut hull and calculating a value of a distance metric for out-of-gamut pixels or LUT points, and subsequently generating a fine gamut hull in the neighborhood of the coarse gamut hull points closest to the out-of-gamut pixel or LUT points under consideration. The out-of-gamut pixel or LUT point is gamut mapped based on the smallest distance metric value calculated.