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287results about How to "Improve peak signal-to-noise ratio" patented technology

Adaptive compressed sensing-based non-local reconstruction method for natural image

The invention discloses an adaptive compressed sensing-based non-local reconstruction method for a natural image. The problems of serious reconstructed image information loss and the like in the prior art are mainly solved. The method is implemented by the steps of: (1) dividing an image into N 32*32 sub-blocks, obtaining a basic sensing matrix Phi' according to a basic sampling rate b and a sensing matrix Phi, and sampling a signal by utilizing Phi' to obtain a basic observation vector; (2) estimating a standard deviation sequence {d1, d2, ..., and dN} of the image according to the basic observation vector; (3) adaptively allocating a sampling rate ai for each sub-block according to the standard deviation sequence {d1, d2, ..., and dN}, and constructing an adaptive sensing matrix, and sampling the signal by utilizing the adaptive sensing matrix to obtain an adaptive observation vector; (4) forming an observation vector of each sub-block by using the basic observation vector and the adaptive observation vector; (5) obtaining an initial solution x0 of the image according to the observation vector; and (6) performing iteration by using x0, and reconstructing the original image until consistency with a finishing condition is achieved to obtain a reconstructed image x'. The method has the advantages of high image reconstruction quality, clear principle and operational simplicity, and is applied to the sampling and reconstruction of the natural image.
Owner:XIDIAN UNIV

Object and fractal-based binocular three-dimensional video compression coding and decoding method

The invention provides an object and fractal-based binocular three-dimensional video compression and decompression method. In binocular three-dimensional video coding, a left channel is used as a basic layer, a right channel is used as an enhancement layer, and the left channel is encoded by an independent motion compensation prediction (MCP) mode. The object and fractal-based binocular three-dimensional video compression coding method comprises the following steps of: firstly, acquiring a video object partition plane, namely an Alpha plane by a video partition method, encoding the initial frame of a left eye through block discrete cosine transformation (DCT), and performing block motion estimation / compensation coding on a non-I frame of the left eye; secondly, determining the area attribute of an image block by utilizing the Alpha plane, and if the block is not within a video object area of the current code, not processing an external block, and if the block is within the video object area of the current code completely, searching the most similar matching block by a full-searching method in a previous frame of an internal block, namely a reference frame searching window of a left eye video; and finally, compressing coefficients of an iterated function system by a Huffman coding method, and if part of pixels of the block are within the video object area of the current code, and the other part of pixels are not within the video object area of the current code, processing a boundary block independently. The right channel is encoded by a MCP mode and a disparity compensation prediction (DCP) mode, the MCP is similar to the processing of the left eye, and the block with the minimum error is used as a prediction result. When the DCP coding mode is performed, the polarization and directionality in a three-dimensional parallel camera structure are utilized fully.
Owner:BEIHANG UNIV

Non-convex compressed sensing image reconstruction method based on redundant dictionary and structure sparsity

The invention discloses a non-convex compressed sensing image reconstruction method based on a redundant dictionary and structure sparsity. A reconstruction process of the method includes: observing original image blocks; using a mutual neighboring technology for clustering observation vectors; using a genetic algorithm for finding optimal atom combinations in a dictionary direction for each class of observation vectors, and preserving species; after species expansion operation is executed on each image block, using a clonal selection algorithm for finding an optimal atom combination on scale and displacement in a determined direction for each image block; reconstructing each image block by the optimal atom combination; and piecing all the constructed image blocks in sequence to form an entire constructed image. Image structure sparsity prior and redundant dictionary direction features are fully utilized, the genetic algorithm is combined with the clonal selection algorithm, and the method is used as a nonlinear optimization reconstruction method to realize image reconstruction. The reconstructed image is good in visual effect, high in peak signal noise ratio and structural similarity, and the method can be used for non-convex compressed sensing reconstruction of image signals.
Owner:XIDIAN UNIV

Wavelet image denoising process based on sliding window adjacent region data selection

The invention relates to a method for denoising wavelet images chosen on the basis of the neighbor data of a sliding window. The method comprises the following steps: step 1, decomposing a noisy image into sub-bands by wavelet transformation processing; step 2, processing the wavelet coefficient of each sub-band according to the following steps: 1), carrying out threshold judgment of the center wavelet coefficient of each neighbor centering on each wavelet coefficient in each sub-band, comparing the correlativity coefficient Theta of each neighbor of the coefficient, and carrying out 2) if the maximal correlativity coefficient Theta is higher than an empirical value, or carrying out step 3 directly if the maximal correlativity coefficient Theta is lower than the empirical value; 2), calculating the Bayes adaptive threshold value of the threshold processing window chosen in 1) so as to obtain a scaling factor; and 3), scaling the wavelet coefficient in the center of the window according to the scaling factor; and step 3, reconstructing the wavelet coefficient so as to obtain the filtered image after processing each sub-band of the wavelet with adaptive sliding window neighbor wavelet process. The method has the advantages of higher peak value signal-to-noise ratio and better protection effect for image edges.
Owner:TIANJIN UNIV

Black-and-white image colorizing method based on two-sided filter

InactiveCN101860655AOvercome the problem of not being able to colorAchieve fixColor signal processing circuitsSignal-to-noise ratio (imaging)Peak value
The invention relates to a black-and-white image colorizing method based on a two-sided filter in the field of image processing, comprising the following steps of: labeling a black-and-white image; carrying out distance conversion on the black-and-white image to obtain the processing priority of an image block; calculating a geometrical distance weight and an average gray gradient value between the current block and an adjacent block under the frame of the two-sided filter, wherein if the average gray gradient value is greater than a threshold value, the similarity of the adjacent block and the current block is insufficient, and therefore, the average gray gradient value can not be used for forecasting the current block; conversely, if the average gray gradient value is less than the threshold value, calculating gray value variable weights of the current and the adjacent blocks; and finally obtaining the recovery value of the current block by the current block, the geometrical distance weight and the gray change weight. The invention overcomes the defect of the dependence assumption of brightness and chromaticity in the colorizing process, effectively colorizes the damaged black-and-white image, and has short used time and high signal to noise ratio of an obtained peak value.
Owner:SHANGHAI JIAO TONG UNIV

Bridge crack image barrier detection and removal method based on generative adversarial network

The invention relates to a bridge crack image barrier detection and removal method based on a generative adversarial network. The method comprises the steps that first, multiple barrier pictures are collected, then tags are added, and the pictures with the tags are input into a Faster-RCNN for training; multiple barrier-containing crack pictures are collected, and barrier position calibration is performed through the Faster-RCNN; second, multiple barrier-free crack pictures are collected, and the pictures are turned over to amplify a dataset; third, the amplified dataset is input into the generative adversarial network to train a crack generation model; fourth, information erasure is performed on the positions of barriers in the barrier-containing crack pictures to obtain damaged images; and fifth, the damaged images are input into a cyclic discrimination restoration model for iteration, and then restored crack images are obtained. Through the method, barrier information in the crack pictures can be accurately detected and removed, the peak signal-to-noise ratio of the restored crack images is increased by 0.6-0.9dB compared with before, and therefore a large quantity of crack images with a high restoration degree are generated under a finite crack dataset condition.
Owner:SHAANXI NORMAL UNIV

Neighborhood adaptive Bayes shrinkage image denoising method based on dual-tree complex wavelet domain

The invention discloses a neighborhood adaptive Bayes shrinkage image denoising method based on a dual-tree complex wavelet domain. The method comprises the following steps: 1) performing dual-tree complex wavelet transform on a noisy image, and performing three-level decomposition to obtain multiple sub-band coefficients; 2) estimating the noise variance by use of a robust median device; 3) processing each sub-band coefficient except the low-pass sub-band coefficient in the following steps: a) calculating the variance of the noisy image in corresponding neighborhood window for each DT-CWT (dual-tree complex wavelet transform) coefficient; b) averaging the variances of the noisy image corresponding to all the coefficients to estimate the neighborhood variance of the noisy image of the sub-band; and c) assuming that a statistical model of the DT-CWT coefficients of the image obeys a GGD (general Gaussian distribution) model, estimating the optimal threshold through a minimal Bayes risk function, and softening the wavelet coefficient in the sub-band; and 4) performing dual-tree complex wavelet inverse transform reconstruction on the wavelet coefficient to obtain the denoised image. The method disclosed by the invention has perfect denoising performance and good adaptivity.
Owner:ZHEJIANG UNIV

Fractal-based binocular stereoscopic video compression coding/decoding method

The invention provides a fractal-based binocular stereoscopic video compression and decompression method. In binocular stereoscopic video coding, a left channel is taken as a basic layer, a single motion compensation predictive mode (MCP) is adopted for coding, and the method comprises the following steps of: performing block DCT transformation coding on a left-eye start frame, performing motion estimation/compensation coding on a left-eye non-I frame, and calculating the pixel sum and the sum of squares of pixels of subblock domain and father block domain-related subblocks; searching the most similar matching block by using a full search method in a previous frame, namely a reference frame searching window of left-eye video; and finally compressing the coefficient of an iterated function system by using a Huffman coding method. A right channel is taken as an enhancement layer, the MCP and a parallax compensation predictive mode (DCP) are adopted for coding, and the lowest error is selected as a predicted result. During the DCP coding mode, the polalization and directionality in a stereoscopic parallel shooting structure are fully utilized; and the corresponding decompression process comprises the following steps of: for the left eye, decoding the start frame I by adopting a reverse DCT transformation mode, and performing Huffman decoding on the non-I frame so as to acquire the coefficient of the iterated function system; performing macrolbock-based decoding, calculating the pixel sum and the sum of squares of pixels of father block domain-related subblocks in the previous frame; and for a right eye, calculating the pixel sum and the sum of squares of pixels of the father block domain-related subblocks in the right-eye previous frame and a left-eye corresponding frame.
Owner:BEIHANG UNIV

Compressive sensing method based on principal component analysis

The invention discloses a compressive sensing method based on principal component analysis and mainly solves the problem of low sampling efficiency in the prior art. The method comprises the following steps of: (1) taking z images from a gray natural image library, taking a 32*32 sub-block from each image which is taken at intervals of three pixels along the horizontal and vertical directions to form a training sample set x1, x2, ..., and xm, and training a full-rank observation matrix Phi(f) for the training sample set x1, x2, ..., and xm by using a principal component analysis method, wherein z is not less than 15 and not more than 25, and m is the quantity of training samples; (2) dividing an image which is required to be sampled into n 32*32 sub-blocks x1, x2, ..., and xn, acquiring an observation matrix Phi according to sampling rate s and the full-rank observation matrix Phi(f), sampling each image sub-block by using the observation matrix Phi, and thus obtaining an observation vector y; (3) acquiring an initial solution x0 of the image according to the observation vector y; and (4) iterating according to the initial solution x0 until iteration is in accordance with end conditions, and thus obtaining a reconstructed image x'. The compressive sensing method has the advantages of high sampling efficiency, high image reconstruction quality and clear principle, and is easy to operate and applicable to sampling and reconstruction of a natural image.
Owner:XIDIAN UNIV

Wavelet threshold image denoising method based on F-type double-chain quantum genetic algorithm

ActiveCN105069760AHigh density search spaceFast convergenceImage enhancementCode spaceDouble chain
The invention discloses a wavelet threshold image denoising method based on an F-type double-chain quantum genetic algorithm. First of all, single-value mapping processing is performed on a coding space, the search space of the algorithm is reduced, and search density is increased; secondly, a self-adaptive step length factor is introduced during quantum updating to enable a step length to change along with the gradient change of a target function at a search point so that the problem of global optimal solution search difficulty caused by an "oscillation" phenomenon generally existing in a conventional searching optimization algorithm at present is effectively solved; and finally, a pi/6 gate is brought forward during chromosome variation updating so that the disadvantage is improved that conventional NOT gate variation cannot update quantum bit probability amplitude. According to the invention, an F_DCQGA optimization algorithm is also applied to a threshold selection mechanism of wavelet threshold de noising, at the same time, a self-adaptive threshold function is brought forward, and accordingly, a conventional wavelet threshold denoising method is improved. The method provided by the invention improves the convergence speed and the search precision of a wavelet threshold function.
Owner:HARBIN ENG UNIV
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