Ningbo University

Gangyi Jiang

Mei Yu

Fen Chen

Zongju Peng

Feng Shao

Yang Song

Yigang Wang

Jing Wang

Yang Wang

Shanshan Liu

Yongqiang Bai

Fucui Li

Kaihui Zheng

Xiaodong Wang

Meiling He

Shengli Fan

Xiangjun Liu

Hua Shao

Junming Zhou

Cuixia Bai

Wujie Zhou

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

The present invention discloses a microscopic three-dimensional measurement system and method based on a moving diaphragm. The present invention adds the diaphragm into the existing optical microscopic imaging system to limit light irradiation angle during imaging for reducing the diameter of blur circle, which extends the depth of field and the depth measurement range, so as to achieve the three-dimensional measurement of large-size objects to be measured. Through changing the position of the added diaphragm, two images with different light incident directions are obtained, which is similar to binocular stereo vision, and then the disparity map is used to predict the depth, so as to carry out the 3D scene reconstruction. Since the depth of field of the imaging system is enlarged and the imaging model has certain non-linear characteristics, the present invention uses quadratic function to express the non-linearity, which reduces the measurement error.

Microscopic three-dimensional measurement system and method based on moving diaphragm

A high dynamic range image information hiding method includes embedding secret information and extracting the secret information. The step of embedding secret information includes obtaining three channel values of every pixel in an original high dynamic range image; according to every channel value and corresponding 5-bit exponent of every pixel, determining an embedding significance bit of the information to be embedded in every channel value of every pixel; embedding information into every channel value of every pixel; and obtaining a high dynamic range image embedded with the secret information. The step of extracting the secret information includes obtaining three channel values of every pixel in the high dynamic range image embedded with the secret information; obtaining an information embedding position of every channel value embedded with the information of every pixel; extracting information from every channel value embedded with the information of every pixel; and obtaining secret information sequences.

High dynamic range image information hiding method

The present invention disclosed a 3D-HEVC depth video information hiding method based on single-depth intra mode, which comprises information embedment part and information extraction part. During information embedment, if the pixels in the candidate list are equal using the encrypt information to modulate the index of the pixel and completes the embedment. If the pixels are different, judging the neighboring CU of the CU whose depth is 2 or 3 and modulating the index of the pixel to complete embedment of the hidden information. The advantage of the present invention is high security, low calculation complexity and small influence on data rate.

3D-HEVC depth video information hiding method based on single-depth intra mode

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 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 method for assessing an objective quality of a stereoscopic video based on reduced time-domain weighting, which considers a time domain perception redundant characteristic of human eyes during a video perception, includes steps of: through a motion intensity mean value and a motion intensity variance of an undistorted stereoscopic video and the motion intensity mean value and the motion intensity variance of each frame group, determining a motion intensity level of each frame group of the undistorted stereoscopic video; for the frame groups having different motion intensity levels, selecting undistorted reduced stereoscopic images through different frame extracting strategies with different densities; measuring a quality of a simultaneous distorted reduced stereoscopic image relative to the undistorted reduced stereoscopic image; through weighting each quality of the simultaneous distorted reduced stereoscopic image relative to the undistorted reduced stereoscopic image, obtaining a quality of a distorted stereoscopic video relative to the undistorted stereoscopic video.

Method for assessing objective quality of stereoscopic video based on reduced time-domain weighting

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.

Digital watermarking based method for objectively evaluating quality of stereo image

A method for color correction of a pair of colorful stereo microscope images is provided, which transmits the color information of the foreground areas and the background area of the reference image to the aberrated image separately for avoiding transmission error of the color information of the varied areas of the pair of the images, thus sufficiently improves the accuracy of the color correction, reduces the difference between the color of the reference image and the color of the aberrated image, and well prepares for the stereo matching of the pair of colorful stereo microscope images as well as for the three-dimensional reconstruction and three-dimensional measurement; on the other hand, during the correction, the correcting procedure is provided automatically without manual work.

Method of color correction of pair of colorful stereo microscope images

A method for detecting a parfocality of a zoom-stereo microscope includes: acquiring four highest definitions corresponding to a plurality of images with a cooperation of four definition judging functions, acquiring a relatively clearest position according to the four highest definitions, comparing a definition in the relatively clearest position with a definition in a parfocal position to judge whether the relatively clearest position is the parfocal position, then adjusting a magnification of the zoom-stereo microscope to acquire the parfocal positions at a finite number of the discrete magnifications, and finally fitting a parfocal curve at the continuous magnifications. The method according to the present invention implements a parfocality detection of the stereo microscope automatically and effectively and increases a productivity, and has a high detecting precision. In addition, the method according to the present invention has a good robustness, so that users needn't intervene and adjust frequently.

Method for detecting parfocality of zoom-stereo microscope

A method for objectively evaluating quality of a stereo image is provided. The method obtains a cyclopean image of a stereo image formed in the human visual system by simulating a process that the human visual system deals with the stereo image. The cyclopean image includes three areas: an occlusion area, a binocular fusion area and a binocular suppression area. Representing characteristics of the image according to the singular value of the image has a strong stability. According characteristics of different areas of the human visual system while dealing with the cyclopean image, the distortion degree of the cyclopean image corresponding to the testing stereo image is presented by the singular value distance between cyclopean images respectively corresponding to the testing stereo image and the reference stereo image, in such a manner that an overall visual quality of the testing stereo image is finally evaluated.

Method for objectively evaluating quality of stereo image

A microscopic image fusion method based on region growing judges the fuzzy degree of the microscopic image and determines the fuzzy seed block by evaluating the definition of every image block in the microscopic image. Then, the fuzzy region and clear region are exactly segmented by region growing and are marked. Finally, a clear and high-quality microscopic image, fused by a plurality of microscopic images, is obtained. Due to the combination of the definition evaluation of the microscopic image, and segmentation of the fuzzy region and clear region by region growing, the fusion results of the microscopic image of the present invention show great advantages at the subjective human perception and the objective evaluation. Furthermore, the present invention has simple calculation and stable result, is easy to be implemented and adapted for fusing the digital optical microscopic images which are shot by shallow depth of field.

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Zhejiang, China

Gangyi Jiang