公开(公告)号：US20230171436A1

公开(公告)日：2023-06-01

申请号：US17768307

申请日：2020-10-16

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Qing Song ,  Arun Raj ,  Guan-Ming Su

IPC: H04N19/86 ,  H04N19/186 ,  H04N19/46 ,  H04N19/132

CPC classification number: H04N19/86 ,  H04N19/46 ,  H04N19/132 ,  H04N19/186

Abstract: A backward reshaping mapping table is initially generated as an inverse of a forward reshaping mapping table. The backward reshaping mapping table is updated by replacing the content-mapped luminance codewords with forward reshaped luminance codewords generated by applying a luminance forward mapping to the sampled luminance codewords. The luminance forward mapping is constructed from the forward reshaping mapping table. The backward reshaping mapping table and the luminance forward mapping are used to generate backward reshaping mappings for creating a reconstructed image from a forward reshaped image. The forward reshaped image is encoded, in a video signal, along with image metadata specifying the backward reshaping mappings. A recipient device of the video signal applies the backward reshaping mappings to the forward reshaped image to create the reconstructed image of the second dynamic range.

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：US11818400B2

公开(公告)日：2023-11-14

申请号：US17768307

申请日：2020-10-16

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Qing Song ,  Arun Raj ,  Guan-Ming Su

IPC: H04N19/00 ,  H04N19/86 ,  H04N19/132 ,  H04N19/186 ,  H04N19/46

CPC classification number: H04N19/86 ,  H04N19/132 ,  H04N19/186 ,  H04N19/46

Abstract: A backward reshaping mapping table is initially generated as an inverse of a forward reshaping mapping table. The backward reshaping mapping table is updated by replacing the content-mapped luminance codewords with forward reshaped luminance codewords generated by applying a luminance forward mapping to the sampled luminance codewords. The luminance forward mapping is constructed from the forward reshaping mapping table. The backward reshaping mapping table and the luminance forward mapping are used to generate backward reshaping mappings for creating a reconstructed image from a forward reshaped image. The forward reshaped image is encoded, in a video signal, along with image metadata specifying the backward reshaping mappings. A recipient device of the video signal applies the backward reshaping mappings to the forward reshaped image to create the reconstructed image of the second dynamic range.