7 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 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.

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.