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33results about How to "Improve denoising performance" patented technology

Signal combined denoising method based on empirical mode decomposition (EMD) and wavelet analysis

The invention belongs to the field of signal processing technologies, and particularly relates to a denoising method of additive white gaussian noise signals at a low signal to noise rate. The method includes the steps that according to autocorrelation of signals, autocorrelation of the signals is solved, the autocorrelation functions of the signals obtain the maximum values at zero points, the amplitude change along with change of time difference and will not attenuate to a small value quickly; EMD is performed on the signals mixed with the gaussian white noise, due to the nature of EMD, the gaussian white noise is not the real white noise any more, however, the statistical property of the white noise approximately exists, in other words, the autocorrelation functions of all the signals mixed with the gaussian white noise obtain the maximum values at zero points, the amplitudes change along with change of the time difference and will attenuate to the small value quickly. Through the difference, IMF components of which the noise plays a main role are selected, and the influences of the noise on the signals can be effectively reduced. Under the condition of the low signal to noise rate, the denoising performance of the method is superior to that of a traditional method, and signal denoising can be completed under the condition of the low signal to noise rate.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA

Transform domain non local and minimum mean square error-based SAR (Synthetic Aperture Radar) image denoising method

InactiveCN103077508AAvoid jitter distortionSuppress noiseImage enhancementImage denoisingDecomposition
The invention discloses a transform domain non local and minimum mean square error-based SAR (Synthetic Aperture Radar) image denoising method which mainly solves the problems of edge excessive smoothness during denoising of an SAR image and difficulty in keeping point targets in the prior art. The transform domain non local and minimum mean square error-based SAR image denoising method comprises the following steps of: inputting an SAR image Y, processing one-layer non-subsample Laplace decomposition on the SAR image Y to obtain a low-frequency image YL and a high-frequency image YH; filtering the YL by using a PPB (Probalistic Patch-Based) filter to obtain a filtered image, carrying out shear wave filter decomposition on the YH to obtain a high-frequency subband image of each direction; modeling by using a Gaussian mixture model and denoising by using MMSE (Minimum Mean Square Error) estimation to obtain denoised high-frequency subband diaphragms; carrying out inverse shear wave transform on the low-frequency image YL and the high-frequency image YH to obtain a space domain image YZ; and classifying the YZ to obtain a final denoising result. The transform domain non local and minimum mean square error-based SAR image denoising method is capable of removing noise in a homogeneous region and well keeping clear edges of the images, and can be used for preprocessing the images.
Owner:XIDIAN 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

Fuzzy entropy-based noisy signal processing method and iterative singular spectrum soft threshold denoising method

The invention discloses a fuzzy entropy-based noisy signal processing method and an iterative singular spectrum (SSA) soft threshold denoising method. The method is suitable for noisy signals. Assuming that the noisy signal of length N xin = {x1, x2, ..., xN} and assuming that the additive white noise therein is uncorrelated with the signal, a d-dimensional vector is constructed and the similarityand fuzzy probability are defined by utilizing an original signal xin; a (d + 1)-dimensional vector is constructed and the corresponding similarity and fuzzy probability are defined by the same method; and the fuzzy entropy is defined in the drawing of the description. For components obtained by utilizing a known signal decomposition method, the singular spectrum distribution of all the components is defined as a fuzzy entropy spectrum. The fuzzy entropy for quantifying the complexity of the system in a chaos theory is utilized to characterize a noise plane and provide a more effective path for the processing of the noisy signal; the fuzzy entropy spectrum-based iterative singular spectrum (SSA-IST) soft threshold denoising method has the denoising performance better than that of the traditional truncated singular spectrum method, and wavelet transform and empirical mode decomposition denoising method.
Owner:DANYANG HUASHEN ELECTRIC APPLIANCE CO LTD

Rolling bearing fault diagnosis method based on vibration signal denoising and envelope analysis

The invention discloses a rolling bearing fault diagnosis method based on vibration signal denoising and envelope analysis and belongs to the field of mechanical fault diagnosis and signal processing.The method comprises the following steps: firstly, performing primary collaborative filtering and denoising processing on four types of vibration signals of an outer ring fault, an inner ring fault,a rolling body fault and a normal condition of a rolling bearing, then performing primary collaborative filtering and denoising processing once again on the signals subjected to collaborative filtering and denoising, further removing noise interfering with fault diagnosis in the signals, afterwards, performing empirical mode decomposition (EMD) on the signals subjected to secondary collaborative filtering and denoising to obtain a plurality of implication mode functions (IMF), and selecting an IMF1 to carry out envelope analysis to judge the fault type of the rolling bearing. The result showsthat the vibration signals can be effectively denoised after being subjected to secondary collaborative filtering, then, envelope analysis based on empirical mode decomposition is carried out on the denoised vibration signals, and fault diagnosis can be accurately and effectively carried out.
Owner:XIANGTAN UNIV

Image denoising method combining wavelet packet and partial differential equation

The invention discloses an image denoising method combining a wavelet packet and a partial differential equation. The method comprises the following steps of carrying out grayscale conversion on a collected original image and carrying out noise adding processing; constructing a new denoising model combining a PM model and a MCD model, through selecting a weight function, distinguishing and isolating noises, and then establishing a second-order differential operator; establishing the image denoising method based on the wavelet packet and the partial differential equation, using the wavelet packet to carry out coefficient decomposition on a noise image, and centrally processing noise information; according to a wavelet packet decomposition coefficient, using wavelet packet inverse transformation to reconstruct the image; and finally, carrying out smoothing processing on the processed image, carrying out simulation through a semi-implicit additive operator split numerical algorithm, comparing a mean square error, a peak signal to noise ratio and definition, and analyzing the validity and the feasibility of the method. By using the method, the noises are effectively removed, and simultaneously, the edge texture and other details of the image can be protected, and denoising performance is excellent.
Owner:NANJING UNIV OF INFORMATION SCI & TECH

Rolling surface defect detection system and method

The invention relates to the field of rolling surface defect detection, in particular to a rolling surface defect detection system and method. The rolling surface defect detection system comprises a control device, a light source generation device, a galvanometer and an identification device, wherein the galvanometer is arranged on a light path between the light source generation device and a rolling surface to be detected; the light source generating device, the galvanometer and the recognition device are all in communication connection with the control device; light beams emitted by the light source generating device are projected to the rolling surface to be measured through scanning of the galvanometer to form stripes; the control device adjusts driving signals of the galvanometer to adjust the positions of the stripes projected to the rolling surface to be measured; and the identification device shoots the rolling surface to be detected to obtain multiple target images and detectsthe defects of the rolling surface to be detected according to the multiple target images. The detection accuracy rate of the defects of the rolling surface to be detected can be effectively improvedby detecting and processing the target images shot multiple times, meanwhile, the system is high in detection precision, the detection process is simple and easy to operate, and high market value isrealized.
Owner:GUANGXI NORMAL UNIV

Data acquisition and processing system of elliptic curved crystal spectrometer

The invention discloses a data acquisition and processing system of an elliptic curved crystal spectrometer. The system comprises a CCD photoelectric conversion module, an AD application module at ananalog front end, an FPGA driving and controlling module, a USB interface transmission module and a system power supply module. The system obtains a spectral image of a laser plasma X-ray, realizes data communication with a PC through the USB interface transmission module, and displays the transmitted data on the PC. The system can acquire image data with different frame frequencies and differentresolutions in real time and at high speed, and transmit and display the acquired data in real time, and the system obtains a higher signal-to-noise ratio and a good visual effect for the spectral image by using wavelet transformation and a median filtering algorithm. The system obtains a spectral diagram of the X-ray by using the denoised spectral image, and converts the relation between pixels and light intensity into the relation between wavelength and intensity through wavelength calibration, so that the spatial resolution of the elliptic curved crystal spectrometer is obtained, and the temperature and the rotating speed of the plasma are obtained.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Real image denoising method based on multi-scale selection feedback network

The invention discloses a real image denoising method based on a multi-scale selection feedback network. The method comprises the following steps: constructing a multi-scale selection module MSB for extracting multiple receptive field scale features; constructing a multi-scale selection feedback network MSFB, wherein the MSFB comprises a shallow feature extraction unit, a plurality of MSBs connected in series, an image reconstruction unit and a degradation model; for image denoising, two dual tasks are constructed: predicting a noise-free image from an original noise image, and degrading the predicted noise-free image to a noise image; repeatedly executing two dual tasks in a plurality of time steps by using the MSFB, and performing multi-stage iteration; in iteration, selectively feeding back high-level semantic information output by the deep MSB of the previous time step to the input end of the shallow MSB of the next time step, and the MSFB is trained through iteration; the training process taking minimization of dual loss as an optimization target and taking a peak signal-to-noise ratio as an evaluation index of network performance; and inputting a noise image into the trained MSFB for de-noising, and outputting the de-noised image.
Owner:SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV

Transform domain non local and minimum mean square error-based SAR (Synthetic Aperture Radar) image denoising method

InactiveCN103077508BAvoid jitter distortionSuppress noiseImage enhancementImage denoisingDecomposition
The invention discloses a transform domain non local and minimum mean square error-based SAR (Synthetic Aperture Radar) image denoising method which mainly solves the problems of edge excessive smoothness during denoising of an SAR image and difficulty in keeping point targets in the prior art. The transform domain non local and minimum mean square error-based SAR image denoising method comprises the following steps of: inputting an SAR image Y, processing one-layer non-subsample Laplace decomposition on the SAR image Y to obtain a low-frequency image YL and a high-frequency image YH; filtering the YL by using a PPB (Probalistic Patch-Based) filter to obtain a filtered image, carrying out shear wave filter decomposition on the YH to obtain a high-frequency subband image of each direction; modeling by using a Gaussian mixture model and denoising by using MMSE (Minimum Mean Square Error) estimation to obtain denoised high-frequency subband diaphragms; carrying out inverse shear wave transform on the low-frequency image YL and the high-frequency image YH to obtain a space domain image YZ; and classifying the YZ to obtain a final denoising result. The transform domain non local and minimum mean square error-based SAR image denoising method is capable of removing noise in a homogeneous region and well keeping clear edges of the images, and can be used for preprocessing the images.
Owner:XIDIAN UNIV

Mathematical algorithm microscopic bladder endoscope imaging system and image processing method

PendingCN113421234AFacilitate accurate observation and diagnosisImprove denoising performanceImage enhancementImage analysisMedical imagingNuclear medicine
The invention belongs to the technical field of medical imaging, and discloses a mathematical algorithm microscopic bladder endoscope imaging system and an image processing method. The system comprises an endoscope handle, an outer sheath tube, an image processing module and a display module; the endoscope handle is connected with the outer sheath tube, the outer sheath tube is provided with a bending part, a direction control mechanism is connected with the bending part, and the direction control mechanism is connected with the image processing module; the end, away from the outer sheath tube, of the bent portion is provided with a tip portion, an image sensor is arranged in the tip portion, the light source module provides a light source for the image sensor, the image sensor is connected with the image receiving module, the image receiving module is connected with the image processing module, and the image processing module is connected with the display module. The method comprises the steps that the light source module provides a light source for the image sensor, controls the angle of the bending part, collects an image in the body of a patient, carries out image processing, and displays image information in the body of the patient on the display module. According to the invention, the quality of medical images is improved, and research and judgment of tumor risks are realized. The device is suitable for medical staff to observe conditions in the body of a patient.
Owner:韩从辉
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