公开(公告)号：US11663702B2

公开(公告)日：2023-05-30

申请号：US17415674

申请日：2019-12-10

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Neeraj J. Gadgil ,  Qing Song ,  Guan-Ming Su

IPC: G06T5/00 ,  H04N19/86 ,  G06T5/20

CPC classification number: G06T5/002 ,  G06T5/20 ,  H04N19/86 ,  G06T2207/20012

Abstract: Methods and systems for reducing banding artifacts when displaying images are described. Identified image bands are filtered using an adaptive sparse finite response filter, where the tap-distance in the sparse filter is adapted according to an estimated width of each image band. Image debanding may be performed across multiple pixel orientations, such as rows, columns, a 45-degree angle, or a −45-degree angle. Given a threshold to decide whether sparse filtering needs to be performed or not, an iterative debanding process is also proposed.

公开(公告)号：US20190281325A1

公开(公告)日：2019-09-12

申请号：US16294875

申请日：2019-03-06

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Qing Song ,  Harshad Kadu ,  Guan-Ming Su

IPC: H04N19/98 ,  H04N19/186 ,  H04N19/14 ,  H04N19/169

Abstract: A standard dynamic range (SDR) image is received. Composer metadata of the first level through the N-th level is generated. Composer metadata of the j-th level is generated based on the composer metadata of the first level through (j−1)-th level. The composer metadata of the first level through the composer metadata of the j-th level is to be used for mapping the SDR image to the j-th target image specifically optimized for the j-th reference target display. The SDR image is encoded with the composer metadata of the first level through the k-th level in an output SDR video signal, where 1

公开(公告)号：US11388408B2

公开(公告)日：2022-07-12

申请号：US17299743

申请日：2019-11-27

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Harshad Kadu ,  Qing Song ,  Guan-Ming Su

IPC: H04N19/132 ,  H04N19/182 ,  H04N19/169 ,  H04N19/98

Abstract: Methods and systems for generating an interpolated reshaping function for the efficient coding of high-dynamic range images are provided. The interpolated reshaping function is constructed based on a set of pre-computed basis reshaping functions. Interpolation schemes are derived for pre-computed basis reshaping functions represented as look-up tables, multi-segment polynomials, or matrices of coefficients in a multivariate, multi-regression representation. Encoders and decoders using asymmetric reshaping and interpolated reshaping functions for mobile applications are also presented.

公开(公告)号：US11277646B2

公开(公告)日：2022-03-15

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 ,  H04N19/182 ,  H04N19/189 ,  H04N19/117

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 dynamic 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：US09747673B2

公开(公告)日：2017-08-29

申请号：US14929587

申请日：2015-11-02

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Qing Song ,  Guan-Ming Su ,  Qian Chen

IPC: G06T5/00 ,  G06T5/20 ,  H04N19/30 ,  H04N19/117 ,  H04N19/154 ,  H04N19/182

CPC classification number: G06T5/008 ,  G06T5/002 ,  G06T5/20 ,  G06T2207/10016 ,  G06T2207/20012 ,  G06T2207/20208 ,  H04N19/117 ,  H04N19/154 ,  H04N19/182 ,  H04N19/30

Abstract: A sparse FIR filter can be used to process an image in order to rectify imaging artifacts. In a first example application, the sparse FIR filter is applied as a selective sparse FIR filter that examines a set of selected neighboring pixels of an original pixel in order to identify smooth areas of the image and to selectively apply filtering to only the smooth areas of the image. The parameters of selective filtering are selected based on the characteristics of an inter-layer predictor. In a second example application, the sparse FIR filter is applied as an edge aware selective sparse FIR filter that examines additional neighboring pixels to the set of selected pixels in order to identify edges and carry out selective filtering of smooth areas of the image. Examples for detecting and removing banding artifacts during the coding of high-dynamic range images are provided.

公开(公告)号：US11895416B2

公开(公告)日：2024-02-06

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: H04N25/615 ,  H04N19/186 ,  H04N19/98 ,  G06T7/90 ,  G06T5/00 ,  G06T5/40

CPC classification number: H04N25/6153 ,  G06T5/009 ,  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：US20220408081A1

公开(公告)日：2022-12-22

申请号：US17764394

申请日：2020-09-29

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Guan-Ming Su ,  Harshad Kadu ,  Qing Song ,  Neeraj J. Gadgil

IPC: H04N19/105 ,  H04N19/196 ,  H04N19/132 ,  H04N19/436 ,  H04N19/154

Abstract: A set of tensor-product B-Spline (TPB) basis functions is determined. A set of selected TPB prediction parameters to be used with the set of TPB basis functions for generating predicted image data in mapped images from source image data in source images of a source color grade is generated. The set of selected TPB prediction parameters is generated by minimizing differences between the predicted image data in the mapped images and reference image data in reference images of a reference color grade. The reference images correspond to the source images and depict same visual content as depicted by the source images. The set of selected TPB prediction parameters is encoded in a video signal as a part of image metadata along with the source image data in the source images. The mapped images are caused to be reconstructed and rendered with a recipient device of the video signal.

公开(公告)号：US11361506B2

公开(公告)日：2022-06-14

申请号：US17045941

申请日：2019-04-08

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Guan-Ming Su ,  Qing Song

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

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：US10701404B2

公开(公告)日：2020-06-30

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 ,  H04N19/136 ,  H04N19/142 ,  H04N19/87 ,  H04N19/179

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.