公开(公告)号：US10419762B2

公开(公告)日：2019-09-17

申请号：US15555047

申请日：2016-03-01

申请人： Dolby Laboratories Licensing Corporation ,  DOLBY INTERNATIONAL AB

发明人： Jan Froehlich ,  Guan-Ming Su ,  Robin Atkins ,  Scott Daly ,  Jon Scott Miller

IPC分类号： H04N19/124 ,  H04N19/136 ,  H04N19/98 ,  H04N19/117 ,  H04N19/132 ,  H04N19/156 ,  H04N19/182 ,  H04N19/154

摘要： A content-adaptive quantizer processor receives an input image with an input bit depth. A noise-mask generation process is applied to the input image to generate a noise mask image which characterizes each pixel in the input image in terms of its perceptual relevance in masking quantization noise. A noise mask histogram is generated based on the input image and the noise mask image. A masking-noise level to bit-depth function is applied to the noise mask histogram to generate minimal bit depth values for each bin in the noise mask histogram. A codeword mapping function is generated based on the input bit depth, a target bit depth, and the minimal bit depth values. The codeword mapping function is applied to the input image to generate an output image in the target bit depth.

公开(公告)号：US10979601B2

公开(公告)日：2021-04-13

申请号：US16091176

申请日：2017-03-31

申请人： Dolby Laboratories Licensing Corporation ,  DOLBY INTERNATIONAL AB

发明人： Jan Froehlich ,  Robin Atkins

IPC分类号： H04N1/60

摘要： 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.

公开(公告)号：US09936199B2

公开(公告)日：2018-04-03

申请号：US15513928

申请日：2015-09-24

申请人： DOLBY LABORATORIES LICENSING CORPORATION

发明人： Jan Froehlich ,  Robin Atkins ,  Qiuwei Wang ,  Guan-Ming Su ,  Peng Yin

IPC分类号： H04N19/186 ,  H04N19/124 ,  H04N9/67

CPC分类号： H04N19/124 ,  H04N9/67 ,  H04N9/68 ,  H04N19/186 ,  H04N19/60 ,  H04N19/85

摘要： Compared to traditional gamma-coded video, perceptually quantized video provides greater flexibility for the transmission and display management of high-dynamic range video, but it does not compresses as efficiently using existing standard codecs. Techniques are described to improve the coding efficiency of perceptually coded video by applying a color cross-talk transformation after the RGB/XYZ to LMS transformation. Such a transform increases luma and chroma correlation for color appearance models, but improves perceptual uniformity and overall coding efficiency for wide color gamut, HDR, signals.