10 results about "Mellin transform" patented technology

The invention discloses a radiation hot spot noise removal method and device based on a dual-CMOS image sensor, and belongs to the technical field of CMOS image sensor noise reduction, and the method comprises the steps: carrying out the calibration of a dual-camera system, and eliminating a mechanical assembly error; the imaging focal planes of the double cameras are ensured to be consistent through definition evaluation; pixel-level geometric alignment is realized by using Fourier-Mellin transform, so that an imaging error is smaller than a specific threshold value; adaptive weighted fusion is performed based on local features, and rigid transition of simple binary selection is avoided. According to the method, image details can be effectively reserved while the hot spot noise is removed, particularly, when an image containing English letters is processed, the contour definition and the recognizability are remarkably superior to those of a traditional algorithm, and an efficient solution is provided for image noise reduction in the intense radiation environment.

The present invention relates to the field of geological exploration and discloses a seismic shot gather denoising method, device, storage medium, and processor. The present invention extracts multiple target seismic trace data from the seismic shot gather, obtains a three-dimensional common-offset vector gather based on the multiple target seismic trace data, and the multiple target seismic trace data have the same offset and the same azimuth; performs a three-dimensional continuous wavelet transform on the three-dimensional common-offset vector gather based on the Fourier-Mellin transform to obtain three-dimensional continuous wavelet transform coefficients; and screens the three-dimensional continuous wavelet transform coefficients based on the apparent velocity difference between coherent noise and effective reflection waves in the three-dimensional common-offset vector gather to obtain target three-dimensional continuous wavelet transform coefficients. Thus, the difference between the effective reflection wave and the coherent noise can be increased, thereby making the coherent noise easier to remove and thus improving the coherent noise removal effect.

The invention provides a Fourier-Mellin transform image geometric matching method and system for pole-logarithm domain decoupling, and the method comprises the steps: estimating a rotation angle through Fourier-Mellin transform, rotating a to-be-matched image of a current frame relative to a template image of a previous frame, and obtaining an axially aligned image search region; converting the template image and the to-be-matched image from a Cartesian coordinate system to a logarithmic polar coordinate system to obtain an image search area corresponding to the logarithmic polar coordinate system; sequentially segmenting the to-be-matched image and the image search area corresponding to the template image along the theta-axis direction according to a set proportion; splicing the horizontally related image area and the vertically related image area into two twin image search areas; calculating a cross power spectrum through phase correlation to obtain scale factors in horizontal and vertical directions; and aligning the images to be matched according to the scale factors in the two directions. The method provided by the invention has equal-proportion scale estimation and rotation estimation capability, scale self-adaption, and robustness to out-of-plane overturning and rotation of a target object.

The invention discloses a single-input single-output channel data analysis and model construction method oriented to an urban environment. In order to improve the reliability and efficiency of a communication system, the method comprises the following steps of: constructing a test platform, designing a detection sequence and constructing a statistical model to realize a complete theoretical closed loop from channel feature extraction to modeling. In a data processing and feature extraction stage, a set of efficient signal processing flow is provided, and high-precision time synchronization is realized through cross-correlation calculation of sliding correlation. According to the modeling method, a sine wave superposition algorithm based on LP-Norm is adopted for a Gaussian channel, and fitting of Doppler power spectrum density is achieved by optimizing Doppler coefficients and harmonic parameters. For non-Gaussian characteristics, a sphere invariant process theory is introduced, channel fading is modeled into a product form of a Gaussian process and a heavy-tailed random variable, the combined influence of multipath and shadow effect in an urban environment is captured, and the two fading components are decoupled through Mellin transform. The effectiveness of the method is verified through simulation.

This invention relates to the field of satellite image processing technology and proposes a local orthorectification method based on video satellite imagery and range vectors. It addresses the problems of existing orthorectification processes, such as errors in direct positioning of single images, poor positioning accuracy, and feature occlusion in the generated orthorectified images due to pitch and swivel angles. This invention utilizes video satellite imagery data from multiple shooting perspectives, selecting images with small pitch and swivel angles for orthorectification. An intermediate orthorectified image is generated from a single frame of the video image, and this intermediate orthorectified image is matched with a reference base map to obtain tie points. Control point information is constructed using an auxiliary DEM, and an image-side compensation parameter model is calculated. Fourier-Melin transform matching is used during the matching process to obtain high-precision, uniformly distributed tie points. This method avoids manual editing, saving time and labor costs.

The application relates to the technical field of medical image processing, in particular to a multi-modal lower limb medical image registration method and system based on manifold learning. The method first performs left-right separation on the whole lower limb CT to obtain independent left and right candidate regions; the local MRI is extracted to obtain a limb mask and determine the side. The local image is resampled with the whole resolution as a reference to realize spatial resolution unification. Local block high-dimensional features are extracted, a near neighbor graph is constructed, and a graph Laplace eigenvalue equation is solved to obtain a multi-channel manifold feature map. The representation ambiguity of manifold embedding is eliminated through symbol correction and orthogonal alignment, then Fourier-Mellin transformation is adopted to realize coarse registration, and local refinement is realized in a limited neighborhood. The application completely separates and independently registers the left and right sides, avoids interference of the opposite structure, realizes stable positioning and accurate alignment of the local MRI in the whole lower limb CT.

The invention belongs to the technical field of image offset correction, and particularly relates to a track defense area offset correction method based on image registration and optimal path selection, electronic equipment and a storage medium. The method comprises the following steps: firstly, calculating offset and a normalized signal power value of a target image and a source image by using Fourier-Mellin transform, and if the value is greater than a set threshold value, correcting a defense area coordinate in the source image according to the offset to obtain a defense area coordinate in the target image; if the value is smaller than a set threshold value, a series of middle frames between the target image and the source image are extracted, Fourier-Mellin transformation is carried out in sequence to search an optimal transformation path, and the defense area coordinates in the source image can be corrected step by step according to the optimal transformation path to obtain the defense area coordinates in the target image. The method can efficiently and accurately correct defence area deviation caused by camera displacement in a high-speed rail monitoring system in various environments.

This invention provides a method and apparatus for simulating positive alpha stable distribution sea clutter amplitude data, relating to the field of sea clutter data processing technology. The method includes: determining a probability density function based on the characteristic function, inverse Laplace transform, Merlin transform properties, and G function of the positive alpha stable distribution; determining a cumulative distribution function based on the probability density function; establishing a correspondence table between multiple target characteristic index parameters, multiple target comprehensive scale parameters, multiple target sea clutter amplitude values, and the values ​​of the cumulative distribution function; and determining the target sea clutter amplitude data matrix based on preset characteristic index parameters, preset scale parameters, a random number matrix, and the correspondence table. By utilizing the characteristic function, inverse Laplace transform, Merlin transform properties, and G function of the positive alpha stable distribution, a closed-loop representation of the probability density function of the positive alpha stable distribution is achieved, enabling the direct simulation and generation of positive alpha stable distribution sea clutter amplitudes.

This invention provides a Fourier-Melin transform image geometric matching method and system with decoupled logarithmic domain, comprising: estimating the rotation angle using Fourier-Melin transform; rotating the image to be matched in the current frame relative to the template image in the previous frame to obtain an axially aligned image search region; transforming the template image and the image to be matched from Cartesian coordinates to logarithmic polar coordinates to obtain the image search region corresponding to the logarithmic polar coordinates; sequentially segmenting the image search regions corresponding to the image to be matched and the template image along the θ-axis according to a set ratio; stitching the horizontally correlated and vertically correlated image regions into two twin image search regions; calculating the cross power spectrum through phase correlation to obtain the scale factors in the horizontal and vertical directions; and aligning the images to be matched according to the scale factors in the two directions. This invention has the ability to estimate scale and rotation proportionally, and is scale adaptive, and is robust to out-of-plane flipping and rotation of the target object.

A seismic shot gather denoising method, relating to the field of geological exploration. The method comprises: extracting a plurality of pieces of target seismic trace data from a seismic shot gather, and obtaining a three-dimensional common-offset-vector tile gather on the basis of the plurality of pieces of target seismic trace data, wherein the plurality of pieces of target seismic trace data have the same offset and the same azimuth angle (101); on the basis of Fourier-Mellin transform, performing three-dimensional continuous wavelet transform on the three-dimensional common-offset-vector tile gather to obtain three-dimensional continuous wavelet transform coefficients (102); and on the basis of an apparent velocity difference between coherent noise and an effective reflection wave in the three-dimensional common-offset-vector tile gather, screening the three-dimensional continuous wavelet transform coefficients to obtain a target three-dimensional continuous wavelet transform coefficient (103). In this way, the difference between the effective reflection wave and the coherent noise can be increased, so as to remove the coherent noise more easily, thereby improving the removal effect of the coherent noise. Also provided are a seismic shot gather denoising apparatus, a storage medium, and a processor.