Tfi Digital Media Limited

Hon Tung Luk

Hon Wah Wong

Yiu Fai Yuen

Hok Kwan Cheung

Chi Keung Fong

Sam Tak Wu Kwong

Yin Sze

Xuyuan Xu

Yuming Li

Mingliang Zhou

Shiqi Wang

Lai Man Po

Mengyang Liu

Chang Zhou

Kin Wai Lau

Wei Gao

The present disclosure relates to a method for image patch selection for training a neural network for image quality assessment. The method includes receiving an input image and extracting one or more image patches from the input image. The moment of the extracted image patches is measured. There is a decision to accept or decline the extracted image patches according to the measured moment. Additional image patches are extracted until a minimum number, N, of extracted image patches are accepted. Alternatively, selection criteria are adjusted until the minimum number of extracted image patches are accepted. The selected image patches are input into a neural network with a corresponding image quality value of the input image, and the neural network is trained with the image patches and image quality value. Also provided is a method for image quality assessment using a neural network trained as set forth above.

Patch selection for neural network based no-reference image quality assessment

A method based on CTU level rate-distortion optimization for rate control in video coding which can effectively improve the perceptual rate-distortion performance and coding efficiency is provided. Firstly, a perceptual rate-distortion model is established using a divisive normalization framework, which characterizes the relationship between local visual quality and coding bits. Subsequently, the established perceptual rate-distortion model is applied to overall distortion optimization which is transformed into a global optimization problem and solved with convex optimization algorithms to obtain optimal CTU level coding bit allocation.

Method based on coding tree unit level rate-distortion optimization for rate control in video coding

A machine learning based initial quantization parameter (QP) prediction method, which can effectively optimize RC performance A machine learning framework for initial QP prediction is proposed, where learning labels are built with the criterion of maximizing rate-distortion (RC) performance, which is proved to be much more effective than the QP determination method with the only consideration on sum of the absolute transformed difference (SATD) complexity. Instead of target bits per pixel for intra frame, target bits per pixel for remaining frames is used as sample data to avoid empirically setting intra frame bit allocation, thus improve the prediction accuracy as the real-time updated remaining bits can better reflect the real-time requirements on the level of QPs. In addition, a clipping and decision approach based on the previous initial QP and the target bits per pixel for all remaining frames is proposed, which can help fast QP adaption and quality smoothness.

Method for initial quantization parameter optimization in video coding

A method and apparatus for converting a standard dynamic range (SDR) video to a high dynamic range (HDR) video. The conversion is adaptive and takes both spatial and temporal information of a current frame and previous frames into consideration such that the majority of pixels falls into the most sensitive regions of human eyes in the target dynamic range, while at the same time, the continuity of luminance is maintained in temporal domain to prevent flickering.

Method and apparatus for converting low dynamic range video to high dynamic range video

An intelligent method and system for expanding and enhancing the color content of video or image to a wider color gamut to make the displayed video or image more pleasing while certain important and sensitive colors such as skin colors are preserved to avoid the perception of visually unnatural image or video artifacts. With the implementation of such method and system, the merits of the wide color gamut display can be fully utilized to provide videos and images of high visual quality.

Method and system for expanding and enhancing color gamut of a digital image

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Hong Kong, China

Hon Tung Luk