34 results about "Mellin transform" patented technology

The invention relates to a Gamma-Gamma distribution parameter estimation method based on a double logarithmic cumulant expectation, and belongs to the technical field of atmospheric turbulence channel parameter estimation of free space optical communication systems. According to the method, a Gamma-Gamma distribution parameter estimation process is simplified greatly through Mellin transform, and a uniform parameter estimation method is built specific to the problems of low fractional moment (FMOM) parameter estimation accuracy and even error estimation in the prior art. Then, further improvements are made, and a concept of double logarithmic cumulant expectation is put forward, so that a finial parameter estimation expression is deduced. Compared with an FMOM, the Gamma-Gamma distribution parameter estimation method has the advantages that relatively high computing efficiency is ensured, and the parameter estimation accuracy is increased.

The invention discloses a score Mellin transform-based optical image encryption method. The method comprises the following steps of: realizing score Mellin transform on an image according to an annular range in an optical mode; receiving a score Mellin transform result by using a charge coupled device (CCD) detector; taking a transform order of the score Mellin transform as a key; and taking a center coordinate of coordinate transform and the inner radius and the outer radius of an annular domain in which the transform is implemented as secondary keys. The method has high attack resistance and high safety.

The present invention provides a method and system for determining near-duplicate images. The method and system includes performing a Fourier-Mellin transform on each of a plurality of images. For each image of the plurality of images, the method and system includes generating a signature based on the Fourier-Mellin transform. The method and system includes comparing the signature of at least one of the images to at least one of the signatures of the other plurality of images and determining any near duplicate images based on the comparing of the signatures.

The present invention is applicable to the technical field of transformers, and provides a method for diagnosing transformer partial discharge faults and an on-line monitoring device, which uses nonlinear mapping to compress characteristic quantities and a Merlin transform algorithm to extract characteristic quantities from the partial discharge signal, and the composition represents the The eigenvectors of the partial discharge signal features are mapped on the feature plane, and the extracted feature quantities are clustered using the unsupervised fuzzy c-means clustering algorithm to form several samples, and each clustered sample is analyzed Phase and waveform features, extract relevant features, use mathematical morphology particle analysis method to compare each sample to establish a sample fingerprint library, and use neural network algorithm to identify the type and pattern of partial discharge signals. In this way, the fault type of transformer partial discharge is determined.

The invention discloses a score Mellin transform-based optical image encryption method. The method comprises the following steps of: realizing score Mellin transform on an image according to an annular range in an optical mode; receiving a score Mellin transform result by using a charge coupled device (CCD) detector; taking a transform order of the score Mellin transform as a key; and taking a center coordinate of coordinate transform and the inner radius and the outer radius of an annular domain in which the transform is implemented as secondary keys. The method has high attack resistance and high safety.

The invention relates to a Gamma-Gamma distribution parameter estimation method based on a double logarithmic cumulant expectation, and belongs to the technical field of atmospheric turbulence channel parameter estimation of free space optical communication systems. According to the method, a Gamma-Gamma distribution parameter estimation process is simplified greatly through Mellin transform, and a uniform parameter estimation method is built specific to the problems of low fractional moment (FMOM) parameter estimation accuracy and even error estimation in the prior art. Then, further improvements are made, and a concept of double logarithmic cumulant expectation is put forward, so that a finial parameter estimation expression is deduced. Compared with an FMOM, the Gamma-Gamma distribution parameter estimation method has the advantages that relatively high computing efficiency is ensured, and the parameter estimation accuracy is increased.

The present invention relates to a reconstruction method of narrow baseline disparity based on multi-scale superpixels and phase correlation. The method includes the following sub-steps: Step 1: Obtaining the global similarity between two input images by Fourier-Mellin transform method Transform the model; step 2: use the multi-scale superpixel method to estimate the pixel extreme error of the global similar transformation model, and obtain the pixel extreme error estimation result; step 3: use the method based on singular value decomposition and random sampling consistency for the pixel extreme error estimation result The sub-pixel phase correlation method performs sub-pixel precision acquisition operation and further obtains the final narrow baseline disparity result; Step 4: reconstructs the 3D information of the image according to the final narrow baseline disparity result. Compared with the prior art, the present invention has the advantages of high precision, good robustness, and high matching efficiency in low-texture regions.

The invention provides a multi-image encryption method based on fractional mellin transform. The method includes the steps of compressing multiple images according to a frequency spectrum cutting and splicing method, then, dividing an image obtained through compression into a plurality of sub-images according to an annular domain, conducting fractional mellin transform on all the sub-images, encrypting a fractional mellin transform outcome into a cryptograph image through magnitude and phase encoding, taking transform degrees of fractional mellin transform as secret keys, and taking a center coordinate for coordinate transform, an inner radius of the annular domain for implementation of transform and an outer radius of the annular domain for implementation of transform as secondary secret keys. According to the multi-image encryption method, the multiple images are compressed through the real-value characteristics of fractional cosine transform, and therefore overweight transmission loads are avoided, and the requirement for instantaneity of image data transmission is met. Fractional mellin transform is then conducted on the image obtained through compression, the fractional order characteristic, the nonlinear characteristic and the like of the fractional cosine transform are fully utilized, and the multi-image encryption method has quite high robustness in terms of clipping prevention and noise prevention. The nonlinear operation is introduced into an encryption system while multi-image encryption transmission can be ensured, and safety of the encryption system is enhanced.

The invention provides a target tracking method based on Fourier-Merlin transform, and belongs to the field of computer vision and digital image processing. The problems of rotation and scale change of a tracked target in a target tracking technology are solved; the method comprises the following specific steps: reading a to-be-tracked video frame sequence, selecting a to-be-tracked target in a first frame mark, performing feature extraction on a search region, converting the search detection region from a Cartesian coordinate system to a logarithmic polar coordinate system, performing rotation and scale transformation on the target under the Cartesian coordinate system, and further converting the target into translation transformation under the logarithmic polar coordinate system; employing fourier-Merlin transform to obtain a tracking target rotation angle and a scale transform size; and carrying out interpolation updating on the tracked target template. According to the method, highrobustness and long-time real-time tracking can be realized, and when the target rotates or the scale changes, the target can be tracked in time.