32results about How to "Reflect quality changes" patented technology

The invention discloses a stereo image quality objective evaluation method based on visual perception. Firstly, a stereo image is divided into a strong edge block, a weak edge block , a flat block and a texture block, and characteristic information reflecting image quality and depth perception of different zone blocks is extracted through computation so as to obtain stereo image characteristic vectors; and then the characteristic vectors of distorted stereo images of the same distortion type in a distorted stereo image set are trained through support vector regression, and each distorted stereo image of the same distortion type is tested by a support vector regression training model to obtain the objective image quality evaluation forecast value of each distorted stereo image. The method has the advantages that the obtained characteristic vector information reflecting the image quality and the depth perception has stronger stability and can better reflect the quality change condition of the stereo images, and the relevance of an objective evaluation result and subjective perception is improved.

The invention discloses a no-reference objective three-dimensional image quality evaluation method based on binocular visual perception. The method comprises the steps of constructing a converging one-eyed image of a distorted three-dimensional image by using an energy gain control model, and constructing left and right disparity images and indefinite left and right images by using left and right viewpoint images; then extracting a curvelet domain feature from the converging one-eyed image, and separately extracting a generalized Gaussian fitting parameter feature and a lognormal distribution fitting parameter feature from the left and right disparity images and the indefinite left and right images, wherein the three features are used as three-dimensional image feature information; and finally, constructing a relation between three-dimensional image features and average subjective scoring differences through support vector regression to obtain an objective quality evaluation predicted value of the distorted three-dimensional image. The method has the advantages that the acquired feature vector of the distorted three-dimensional image has strong stability and can reflect the quality change condition of the distorted three-dimensional image, the objective evaluation has good consistency with subjective perception of human eyes, and the correlation between the objective evaluation result and the subjective perception is improved.

The invention discloses a tone mapping image quality objective evaluation method based on a global characteristic, wherein the method comprises two processes of a training period and a testing period. Influences of a natural scene statistics characteristic and a color statistics characteristic to tone mapping are considered. A global characteristic vector of a tone mapping image is extracted. Then support vector regression is utilized for training the global characteristic vectors of all tone mapping images in a training image set, thereby constructing a quality predication model. In the testing period, through calculating the global characteristic vector of the tone mapping image for testing, and a quality objective evaluation predicated value of the tone mapping image is obtained through predicating according to the quality predication model which is constructed in the training period. Because the obtained global characteristic vector information has relatively high stability and furthermore can well reflect the quality change condition of the tone mapping image, correlation between an objective evaluation result and subjective perception is effectively improved.

The invention discloses a visual perception-based three-dimensional image quality objective evaluation method which comprises the steps of: firstly, obtaining an objective evaluation measurement value of each pixel point through calculating a local phase characteristic and a local amplitude characteristic of each pixel point in left and right viewpoint images of a three-dimensional image, dividing the three-dimensional image into a shielding region, a binocular inhibition region and a binocular fusion region by a region detection method; and secondly, evaluating all regions respectively and fusing evaluation results to obtain a final image quality objective evaluation prediction value. The visual perception-based three-dimensional image quality objective evaluation method has the advantages that the obtained information for reflecting local phase and local amplitude characteristics has strong stability and can well reflect quality change condition of the three-dimensional image, and the image quality evaluation method of the shielding region, the binocular inhibition region and the binocular fusion region can well reflect the visual perception characteristic of the human visual system, and is effectively improved in correlation of objective evaluation result and subjective perception.

The invention discloses a stereo-image quality objective evaluation method based on a characteristic image. Parallax stereograms of an original and undistorted stereo-image and a distorted and to be evaluated stereo-image are respectively calculated, then by means of the minimum changing image which can be observed by eyes of a left eyepoint image of the distorted and to be evaluated stereo-image and a gradient of disparity image of an anaglyph between a left eyepoint image and a right eyepoint image of the original and undistorted stereo-image, a first structure similarity of the two parallax stereograms is calculated, and an objective evaluation value of the image quality of the distorted and to be evaluated stereo-image is obtained. The stereo-image quality objective evaluation method based on a characteristic image has the advantages that the obtained Parallax stereograms can well reflect the effects of different parallax on stereo-image quality, the structure similarity which is calculated and obtained according to the characteristic image can well reflect the changing conditions of stereo-image quality, the evaluation result is enabled to be more accord with a human visual system, and thereby the correlation of the objective evaluation result and the subjective perception is effectively improved.

The invention discloses a panoramic video quality evaluation method, which divides the original panoramic video and the panoramic video to be evaluated into several frame groups, and uses a cube projection method to project them on six planes of the cube, and then calculates the and the spatial similarity and frequency domain similarity of each projection surface, and according to the spatial similarity and frequency domain similarity of all frame groups and all projection surfaces, the objective evaluation value of the panoramic video to be evaluated is obtained by fusion, because the cube projection avoids The complex viewport prediction is achieved, and the extracted spatial and temporal features have strong stability and can better reflect the quality changes of panoramic videos, thus effectively improving the correlation between objective evaluation results and subjective perception .

The invention discloses a method for evaluating the quality of a down reference three-dimensional video. The method comprises the steps that based on a depth image drawing method, a plurality of virtual viewpoint drawing videos are drawn, a four-dimensional space diagram is constructed, since the constructed four-dimensional space diagram considers the influence of color and depth video distortion to the drawing quality of the virtual viewpoints, so that a three-dimensional video is operated and compared directly to better evaluate the influence of the color and the depth video distortion to the drawing quality of the virtual viewpoints, thereby effectively improving the evaluation performance of the three-dimensional video; and a predicted value of objective quality evaluation of a fuzzy three-dimensional video to be evaluated can be calculated by calculating a coefficient distance and frequency ratio distance information according to the DCT coefficient statistical characteristics of different sub-bands and frequency bands of all four-dimensional space bodies in the four-dimensional space diagram, and thus the quality change condition of the three-dimensional video can be well reflected by less information.

The invention discloses a reference-free three-dimensional picture quality objective evaluation method based on machine learning. The reference-free three-dimensional picture quality objective evaluation method comprises the steps that a vision dictionary list is structured in a training stage, sparse coefficient matrixes of all subblocks in a left viewpoint picture and all subblocks in a right viewpoint picture are calculated respectively for the left view point picture and the right view point picture of any distortion three-dimensional picture according to the structured vision dictionary list, the characteristic vector of the left viewpoint picture and the characteristic vector of the right viewpoint picture are obtained through the maximum pooling method, characteristic extraction is simple, and the computation complexity is low; a support vector regression training model of the left viewpoint picture and a support vector regression training model of the right viewpoint picture are structured, objective quality evaluation predictive values, corresponding to each characteristic vector in a test sample data set, of the left viewpoint picture and the right viewpoint picture respectively are obtained through prediction, weighing is conducted according to characteristic vector information, the objective quality evaluation prediction value of the three-dimensional picture is obtained, and the correlation between the objective evaluation result and subjective perception is high.

The invention discloses a method for objectively evaluating the quality of a three-dimensional image based on three-dimensional structural similarity. The method comprises the following steps of: calculating to obtain parallax space maps of an initial undistorted three-dimensional image and a distorted three-dimensional image to be evaluated respectively, calculating to obtain the three-dimensional structural similarity between the parallax space map of the initial undistorted three-dimensional image and the parallax space map of the distorted three-dimensional image to be evaluated, and obtaining the objective evaluation predicted value of the quality of the distorted three-dimensional image to be evaluated. The method has the advantages that the obtained three-dimensional structural similarity can reflect the influence of different parallaxes on the three-dimensional image well, and only a unit with the low three-dimensional structural similarity can be evaluated, so that the objective evaluation result and the correlation of subjective perception are effectively improved.