Ningbo University

Fen Chen

Gangyi Jiang

Mei Yu

Yang Song

Jing Wang

Zongju Peng

Shanshan Liu

Meiling He

Feng Shao

Yongqiang Bai

Yang Wang

Fucui Li

Kaihui Zheng

Xiaodong Wang

Yaqi Lv

Wujie Zhou

Zhaoyun Wang

A 3D-HEVC inter-frame information hiding method based on visual perception includes steps of information embedding and information extraction. In the step of information embedding, the human visual perception characteristic is considered, stereo salient images are obtained by a stereo image salient model, and the stereo salient images are divided into salient blocks and non-salient blocks with an otsu threshold. The coding quantization parameters are modified according to different modulation rules for different regions. Then, based on the modified quantization parameters, the coding-tree-units are coded to complete the information embedding. In the step of information extraction, no original video is needed, no any side information needs to be transmitted, and the secret information can be blindly extracted. The present invention combines with the human visual perception characteristic, and selects P frames and B frames as embedded frames for effectively reducing the decrease of the stereo video subjective quality.

3D-HEVC inter-frame information hiding method based on visual perception

A method for evaluating quality of tone-mapping image based on exposure analysis is provided, which explores the exposure properties on each area of the high dynamic range image utilizing the pre-exposure method and divides the high dynamic range image into three parts of an easy overexposed area, an easy underexposed area and an easy natural-exposed area, wherein different quality characteristics are extracted in different areas, which is capable of ensuring that the follow-up quality characteristic extraction is more targeted. The present invention takes the difference of distortion between the tone-mapping image and the conventional image into account, and extracts image characteristics such as the abnormal exposure rate, the underexposed residual energy, the overexposed residual energy and the exposure color index, so as to accurately reflect the quality degradation of the tone-mapping image.

Method for evaluating quality of tone-mapping image based on exposure analysis

A zero-watermarking registration and detection method for HEVC video streaming against requantization transcoding is provided. To increase an attack-resistance of a registration watermarking, the registration method firstly processes depth values corresponding to respective brightness blocks in a target video streaming with a depth binarization during constructing registration watermarking information through depth features, because the depth binarization well reflects a robustness of the registration watermarking. A first watermarking information matrix including a part of the depth values after the depth binarization is encrypted with a random matrix, so as to increase a safety of the registration watermarking. The registration method directly generates zero-watermarking through the depth features of the video streaming without modifying original carrier information and affecting a watermarking transparency. Meanwhile, the registration method has a strong robustness against attacks, such as the requantization transcoding of quantization parameters within a certain range of variation and common signal processing.

Zero-watermarking registration and detection method for HEVC video streaming against requantization transcoding

An objective assessment method for a stereoscopic image quality combined with manifold characteristics and binocular characteristics trains a matrix after dimensionality reduction and whitening obtained from natural scene plane images through an orthogonal locality preserving projection algorithm, for obtaining a best mapping matrix. Image blocks, not important for visual perception, are removed. After finishing selecting the image blocks, through the best mapping matrix, manifold characteristic vectors of the image blocks are extracted, and a structural distortion of a distorted image is measured according to a manifold characteristic similarity. Considering influences of an image luminance variation on human eyes, a luminance distortion of the distorted image is calculated according to a mean value of the image blocks. After obtaining the manifold similarity and the luminance similarity, quality values of the left and right viewpoint images are processed with linear weighting to obtain a quality value of the distorted stereoscopic image.

Objective assessment method for stereoscopic image quality combined with manifold characteristics and binocular characteristics

An objective assessment method for a color image quality based on online manifold learning considers a relationship between a saliency and an image quality objective assessment. Through a visual saliency detection algorithm, saliency maps of a reference image and a distorted image are obtained for further obtaining a maximum fusion saliency map. Based on maximum saliencies of image blocks in the maximum fusion saliency map, a saliency difference between each reference image block and a corresponding distorted image block is measured through an absolute difference, and thus reference visual important image blocks and distorted visual important image blocks are screened and extracted. Through manifold eigenvectors of the reference visual important image blocks and the distorted visual important image blocks, an objective quality assessment value of the distorted image is calculated. The method has an increased assessment effect and a higher correlation between an objective assessment result and a subjective perception.

Objective assessment method for color image quality based on online manifold learning

A video quality objective assessment method based on a spatiotemporal domain structure firstly combines a spatiotemporal domain gradient magnitude and color information for calculating a spatiotemporal domain local similarity, and then uses variance fusion for spatial domain fusion. The spatiotemporal domain local similarity is fused into frame-level objective quality value, and then a temporal domain fusion model is established by simulating three important global temporal effects, which are a smoothing effect, an asymmetric track effects and a recency effect, of a human visual system. Finally, the objective quality values of the distorted video sequence are obtained. By modeling the human visual temporal domain effect, the temporal domain weighting method of the present invention is able to accurately and efficiently evaluate the objective quality of the distorted video.

Video quality objective assessment method based on spatiotemporal domain structure

An objective assessment method for a stereoscopic video quality based on a wavelet transform fuses brightness values of pixels in a left viewpoint image and a right viewpoint image of a stereoscopic image in a manner of binocular brightness information fusion, and obtains a binocular fusion brightness image of the stereoscopic image. The manner of binocular brightness information fusion overcomes a difficulty in assessing a stereoscopic perception quality of a stereoscopic video quality assessment to some extent and effectively increases an accuracy of a stereoscopic video objective quality assessment. When weighing qualities of each frame group in a binocular fusion brightness image video corresponding to a distorted stereoscopic video, the objective assessment method fully considers a sensitivity degree of a human eye visual characteristic to various types of information in the video, and determines a weight of each frame group based on a motion intensity and a brightness difference.

Objective assessment method for stereoscopic video quality based on wavelet transform

A digital watermarking based method for objectively evaluating quality of stereo image includes: at transmitting terminal, extracting characteristics of the left-view image and the right-view image of an undistorted stereo image in DCT domain and embedding digital watermarking obtained by processing quantization coding on the characteristics into the DCT domain; at a receiving terminal, detecting the digital watermarking embedded in the distorted stereo image and processing decoding and inverse quantization to extract the embedded characteristics of the left-view image and the right-view image of the stereo image, obtaining a stereo perception value and a view quality value of the distorted stereo image according to the embedded characteristics, and finally obtaining an objective quality score of the distorted stereo image utilizing a support vector regression model.

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Zhejiang, China

Fen Chen