Ningbo University

Mei Yu

Gangyi Jiang

Fen Chen

Feng Shao

Zongju Peng

Yigang Wang

Yang Song

Shanshan Liu

Fucui Li

Shengli Fan

Yi Liu

Jing Wang

Yongqiang Bai

Yang Wang

Xiaodong Wang

Meiling He

Kaihui Zheng

Wujie Zhou

Zhaoyun Wang

Xiangjun Liu

Junming Zhou

Cuixia Bai

Li Cui

Yaqi Lv

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

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

A rapid autofocus method for a stereo microscope includes steps of: calculating a disparity of each of stereo microscopic images in a stereo microscopic calibration image sequence; extracting a clear stereo microscopic image sequence from the stereo microscopic calibration image sequence; then, finding out a largest disparity and a smallest disparity among the disparities of all the stereo microscopic images in the clear stereo microscopic image sequence; at a chosen magnification, arbitrarily acquiring a stereo microscopic image; finally, determining a disparity range according to the disparity of the acquired stereo microscopic image, the largest disparity and the smallest disparity, and realizing an autofocus of a target object in the acquired stereo microscopic images. The disparity range is obtained via once off-line calibration at the same magnification, and applicable to the autofocus at an arbitrary timing.

Rapid autofocus method for stereo microscope

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

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

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.

Growing community of inventors

Zhejiang, China

Mei Yu