7 results about "Multiplicative noise" patented technology

The present application belongs to the technical field of remote sensing image processing, and provides a SAR image denoising method and device based on a logarithmic domain diffusion model. The denoising method comprises: preprocessing: converting an original SAR amplitude image to a logarithmic domain to obtain a starting input image for a diffusion process; forward diffusion: constructing a forward diffusion path based on a non-central Gaussian distribution, simulating a noise injection process, and generating a noisy image sequence; neural network model noise prediction: performing feature extraction and fusion on the noisy image and physical metadata through a pre-constructed neural network model, and outputting a noise residual prediction result; backward sampling reconstruction: iteratively sampling using the noise residual prediction result to reconstruct a denoised SAR image. The denoising method solves the distribution mismatch problem of traditional diffusion models for SAR multiplicative noise, improves the denoising precision, and preserves the image texture and structure information.

The invention discloses a sonar video sequence denoising method and system, a readable medium and an underwater vehicle, and has the advantages that weak supervised learning under a non-registered dynamic video is realized, the limitation that input and output pixel level alignment is required by a traditional method is overcome, a supervised target is allowed to have non-rigid infinitesimal displacement in a local field, and the accuracy of the noise reduction of the sonar video sequence is improved. Sonar continuous video frames containing tiny non-rigid jitter are directly used for training. And constructing a time sequence-space combined lightweight mapping mechanism: redefining a channel mixing concept in the LUT, migrating from a space domain dimension to a time sequence dimension, and simultaneously realizing denoising and inter-frame smoothing through table look-up operation on the premise of not increasing the calculation amount. In order to solve the problem of LUT quantization loss under weak supervision, an anti-noise LUT conversion method is provided, it is ensured that under the condition of low bit wide storage, the description capability of a weak sonar target can still be kept, and logarithm transformation of an image is introduced so as to adapt to multiplicative noise caused by speckle noise.

The application discloses a blood flow parameter determination and display method and device, an electronic device and a computer readable storage medium. The blood flow parameter determination method comprises the following steps: acquiring echo data of multiple pulses of wall-filtered pixel points in an imaging region; constructing four sub-sequences based on the echo data, and calculating fourth-order cumulants of the echo data based on the four sub-sequences; and calculating the blood flow parameter based on the echo data and the fourth-order cumulants. In the application, the four sub-sequences are constructed based on the echo data of multiple pulses of wall-filtered pixel points in the imaging region, the fourth-order cumulants of the echo data are calculated by using the constructed sub-sequences, and the problem that the autocorrelation method is affected by the accuracy of the blood flow parameter estimation in the additive Gaussian color noise and multiplicative noise background is eliminated by using the characteristics that the fourth-order cumulants are not sensitive to the additive Gaussian color noise and multiplicative noise, so that the accuracy of the blood flow parameter estimation is improved.

The invention discloses a particle number state prediction method and device, equipment and a medium. The method comprises the steps of performing data prediction on current state information based on a target system model corresponding to a target particle counter and target noise parameter information to determine a basic state prediction value and a basic measurement prediction value corresponding to a target sample; performing covariance calculation on the basic state prediction value based on a preset singular value decomposition method to determine a prediction covariance error, and performing residual calculation on the basic measurement prediction value based on a preset residual rule to determine a measurement prediction error; and performing gain calculation on the prediction covariance error based on a preset adjustment fusion strategy to determine a target gain, and performing state updating on the basic state prediction value based on the target gain and the measurement prediction error to obtain a target state prediction value corresponding to the target sample. According to the technical scheme, the influence caused by multiplicative noise can be effectively reduced, and the accuracy of a particle number state result is improved.

A method and an apparatus for evaluating transmission impairments of a multiplexing converter. According to the method, impairments of a multiplexing converter are equivalent to the equivalent multiplicative noise and the equivalent additive noise, so as to allow evaluation of transmission impairments of the multiplexing converter, thereby to allow evaluation of the performance of a communication system. The multiplexing converter is a multiplexing analog-to-digital converter, or a multiplexing digital-to-analog converter. According to the present application, impairments of a multiplexing converter can be evaluated accurately, the performance evaluation of a communication system using the multiplexing converter is given, without being affected by an amplitude, a modulation format and a transmission rate of an input signal.

The invention discloses an intelligent detection system and method for welding defects of an electrolytic bath polar plate based on machine vision, and relates to the technical field of industrial vision detection. The method comprises the following steps: firstly, controlling an external heat source to carry out transient thermal excitation on an electrolytic cell polar plate welding seam, and synchronously acquiring high-resolution texture field data and time sequence thermal response field data on the surface of a polar plate; constructing a space-time covariance matrix by using an orthogonal heat flow projection analysis module, determining a background heat flow principal axis, generating a thermal anomaly residual image by calculating an orthogonal projection residual, and eliminating multiplicative noise caused by uneven surface emissivity from a physical level; the gradient direction included angle between the texture field and the thermal anomaly residual field is further calculated by using a heterogeneous gradient mutual exclusion judgment module, a heterogeneous gradient mutual exclusion correction factor is constructed, and the interference degree of the surface texture on thermal anomaly judgment is quantified. According to the method, the problems that the false alarm rate of the high-reflection metal surface is high and the subsurface defects are difficult to detect are effectively solved, and the detection robustness and accuracy are remarkably improved.