公开(公告)号：US20210368212A1

公开(公告)日：2021-11-25

申请号：US17282523

申请日：2019-10-02

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Qing SONG ,  Neeraj J. GADGIL ,  Guan-Ming SU ,  Peng YIN ,  Arun RAJ

IPC: H04N19/86 ,  H04N19/117 ,  H04N19/189 ,  H04N19/182

Abstract: Methods and systems for reducing banding artifacts when displaying high-dynamic-range images reconstructed from coded reshaped images are described. Given an input image in a high dyna mic range (HDR) which is mapped to a second image in a second dynamic range, banding artifacts in a reconstructed HDR image generated using the second image are reduced by a) in darks and mid-tone regions of the input image, adding noise to the input image before being mapped to the second image, and b) in highlights regions of the input image, modifying an input backward reshaping function, wherein the modified backward reshaping function will be used by a decoder to map a decoded version of the second image to the reconstructed HDR image. An example noise generation technique using simulated film-grain noise is provided.

公开(公告)号：US20190222866A1

公开(公告)日：2019-07-18

申请号：US16329392

申请日：2017-08-28

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Qing SONG ,  Harshad KADU ,  Qian CHEN ,  Guan-Ming SU

IPC: H04N19/98 ,  H04N19/60 ,  H04N19/105 ,  H04N19/189 ,  H04N19/186 ,  H04N19/176

Abstract: Real-time forward reshaping, comprising selecting a statistical sliding window that indexes with the current frame, having also, a look-back frame and a look-ahead frame, determining whether they are part of the current scene, determining a noise parameter, a luma transfer function and a luma forward reshaping function based on the luma transfer function and the noise parameter within the current scene, selecting a central tendency sliding window of the current frame and the look-back frame within the current scene, and determining a central tendency luma forward reshaping function. The chroma reshaping comprises analyzing statistics for the extended dynamic range (EDR) weights and EDR upper bounds, mapping these to standard dynamic range (SDR) weights and SDR upper bounds based on the central tendency luma forward reshaping function, determining a chroma content-dependent polynomial and a central tendency chroma forward reshaping polynomial and generating chroma MMR coefficients.

公开(公告)号：US20220295020A1

公开(公告)日：2022-09-15

申请号：US17630901

申请日：2020-07-27

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Guan-Ming SU ,  Harshad KADU ,  Neeraj J. GADGIL ,  Qing SONG ,  Yoon Yung LEE

IPC: H04N9/04 ,  G06T5/00 ,  G06T5/40 ,  G06T7/90 ,  H04N19/186 ,  H04N19/98

Abstract: A device includes an electronic processor configured to define a first set of sample pixels from a set of sample pixels determined from received video data according to a first electro-optical transfer function (EOTF) in a first color representation of a first color space; convert the first set of sample pixels to a second EOTF via a mapping function, producing a second set of sample pixels according to the second EOTF; convert the first and second set of sample pixels from the first color representation to a second color representation of the first color space; determine a backward reshaping function by repeatedly applying and adjusting a sample backward reshaping function so as to minimize a difference between predicted pixel values obtained by applying the sample backward reshaping function to the pixels of the converted first set and the pixels of the converted second set.

公开(公告)号：US20210195221A1

公开(公告)日：2021-06-24

申请号：US17054495

申请日：2019-05-09

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Qing SONG ,  Harshad KADU ,  Guan-Ming SU

IPC: H04N19/186 ,  H04N19/23 ,  H04N19/105 ,  H04N19/159 ,  H04N19/44

Abstract: 3D mapping statistics are generated for a first image of a first dynamic range and a second image of a second dynamic range different from the first dynamic range. Multivariate multiple regression (MMR) coefficients are generated by solving an optimization problem formulated using an MMR matrix built with the 3D mapping statistics without a letterbox constraint, and used to generate chroma mappings for predicting chroma codeword values of the second image. It is determined whether a letterbox exists in the images. If so, it is determined whether the chroma mappings accurately predict chroma codeword values in the second image. A reconstructed image generated by a recipient device by backward reshaping one of the images is rendered by a display device operating in conjunction with the recipient device.

公开(公告)号：US20210150812A1

公开(公告)日：2021-05-20

申请号：US17045941

申请日：2019-04-08

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Guan-Ming SU ,  Qing SONG

IPC: G06T17/20 ,  G06T3/40 ,  G06T9/00 ,  G06K9/62 ,  G06N3/04

Abstract: Methods and systems for mapping images from a first dynamic range to a second dynamic range using a set of reference color-graded images and neural networks are described. Given a first and a second image representing the same scene but at a different dynamic range, a neural network (NN) model is selected from a variety of NN models to determine an output image which approximates the second image based on the first image and the second image. The parameters of the selected NN model are derived according to an optimizing criterion, the first image and the second image, wherein the parameters include node weights and/or node biases for nodes in the layers of the selected NN model. Example HDR to SDR mappings using global-mapping and local-mapping representations are provided.

公开(公告)号：US20190320191A1

公开(公告)日：2019-10-17

申请号：US16303028

申请日：2017-05-17

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Qing SONG ,  Guan-Ming SU ,  Qian CHEN ,  Tao CHEN

IPC: H04N19/30 ,  H04N19/124 ,  H04N19/85 ,  H04N19/98 ,  H04N19/136 ,  H04N19/186

Abstract: Methods and systems for adaptive chroma reshaping are discussed. Given an input image, a luma-reshaped image is first generated based on its luma component. For each chroma component of the input image, the range of the pixel values in the luma reshaped image is divided into bins, and for each bin a maximal scale factor is generated based on the chroma pixel values in the input image corresponding to the pixels of the luma reshaped image in the bin. A forward reshaping function is generated based on a reference reshaped function and the maximal scale factors, and reshaped chroma pixel values for the chroma component are generated based on the forward reshaping function and the corresponding pixel values in the luma reshaped image. Implementations options using look-up tables for mobile platforms with limited computational resources are also described.

公开(公告)号：US20180115777A1

公开(公告)日：2018-04-26

申请号：US15795093

申请日：2017-10-26

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Sankaranarayanan PIRAMANAYAGAM ,  Qing SONG ,  Guan-Ming SU

IPC: H04N19/186 ,  H04N19/182 ,  H04N19/587

CPC classification number: H04N19/186 ,  G06T5/007 ,  G06T7/00 ,  G06T9/00 ,  G06T2207/20208 ,  G09G5/005 ,  G09G2320/0673 ,  G09G2320/0693 ,  G09G2340/02 ,  G09G2370/04 ,  H04N19/182 ,  H04N19/587 ,  H04N19/68 ,  H04N19/98

Abstract: Methods for screen-adaptive decoding of video with high dynamic range (HDR) are described. The methods combine the traditional compositing and display management steps into one screen-adaptive compositing step. Given decoded standard dynamic range (SDR) input data, metadata related to the prediction of output HDR data in a reference dynamic range, and the dynamic range of a target display, new output luma and chroma prediction functions are generated that map directly the input SDR data to output HDR data in the target dynamic range, thus eliminating the display management step.