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270 results about "Reverse transformation" patented technology

Infrared image and visible image fusion method based on guide filtering

The invention provides an infrared image and visible image fusion method based on guide filtering. The method comprises the steps of: firstly, expanding the guide filtering to multiple scales, and performing multi-scale decomposition on an infrared image and a visible image by using the multi-scale guide filtering, so as to obtain a low-frequency subband and a high-frequency subband; performing nonsubsampled directional filtering on the high-frequency subband, so as to obtain a directional subband coefficient; applying different fusion rules to the directional subband coefficient and a low-frequency subband coefficient, so as to obtain the corresponding directional subband coefficient and the low-frequency subband coefficient after fusion, and finally, performing directional filtering reconstruction and multi-scale reverse transformation based on the guide filtering, so as to obtain a final fusion image. According to a fusion result obtained by adopting the method, the edge and thermal radiation characteristics of an infrared image object are preferably kept, scene details of the visible image can be preferably reserved, and the information content of a fusion image is increased, so that the edge and details of the fusion image are enriched.
Owner:ORDNANCE TECH RES INST OF THE GENERAL ARMAMENT DEPT PLA

Method And System For Computational Transformation

The invention generally relates to computational transformation process, which has applications in cryptography, random number generation, hash code generation etc. The computational transformation module uses a keyset, which is designed using a two dimensional array. Since the process of forward transformation used in the invention is a symmetric encryption process and if used to send data securely over a communications network, the same keyset needs to be present at the sending computer to encrypt the data and the receiving computer to go through a reverse transformation and decrypt the data. When the first ‘n’ bit block of input-data is transformed into the first ‘m’ bit block of output-data, the keyset is transformed into a different keyset based on a nonlinear or one-way transformation on the keyset. The next input block is encrypted using a transformed keyset, hence satisfying Shanons theory of perfect secrecy. It uses the same logic with additional parameters and operations to create random numbers and unique hash codes. The computational transformation process is a one-way process which is based on a principle where given the input value ‘x’, it is easy to transform ‘x’ to ‘y’ using a function ‘F’ i.e. F(x)=y. However, given ‘y’ in the range of F, it is hard to find an x such that F(x)=y. In this system, the same transformation function and same keyset is used for both encryption as well as decryption with only a change in the constant value.
Owner:SINGANAMALA PRAHLAD P

Permanent-magnet synchronous motor start-up smooth switching method

The invention provides a permanent-magnet synchronous motor start-up smooth switching method. The method includes the following steps: presupposing that given torque current is identically 1.5 times that of rated current of a permanent magnet synchronous motor; presupposing that a rotor position angle is increased progressively at a T-squared growth rate, and enabling the permanent magnet synchronous motor to rotate at a constant accelerated speed; when the speed of the permanent magnet synchronous motor reaches 30% of a rated rotation speed, beginning to carry out switching transition, enabling a rotor position angle used for PARK transformation and reverse transformation to gradually approach an actual rotor position angle acquired by a position and speed estimator, and meanwhile, enabling the presupposed torque current to gradually approach torque current calculated by adopting the actual rotor position angle; and when time for switching transition arrives, switching closed-loop control states of the speed, the position and the current. The method can achieve the purposes that the rotor position and phase current are undistorted and the rotation speed does not oscillate in start-up switching of the permanent-magnet synchronous motor only by one-time parameter setting under any load.
Owner:梵帝风机(泰州)有限公司

Visible light and infrared image fusion algorithm based on NSCT domain bottom layer visual features

The invention provides a visible light and infrared image fusion algorithm based on non-subsample contourlet transform (NSCT) domain bottom layer visual features.Firstly, visible light and infrared images are subjected to NSCT, high and low frequency subband coefficients of the visible light and the infrared images are obtained, then phase equalization, neighborhood space frequency, neighborhood energy and other information are combined, the pixel active levels of the low frequency subband coefficients are comprehensively measured, fusion weights of the low frequency subband coefficients of the visible light and infrared images are obtained respectively, and therefore low frequency subband coefficients of fusion images are obtained; the pixel active levels of the high frequency subband coefficients are measured through the combination of phase equalization, definition, brightness and other information, fusion weights of the high frequency subband coefficients of the visible light and infrared images are obtained respectively, then high frequency subband coefficients of the fusion images are obtained, finally, NSCT reverse transformation is utilized, and final fusion images are obtained.Detail information of source images can be effectively reserved, and meanwhile useful information of the visible light images and the infrared images is synthesized.
Owner:云南联合视觉科技有限公司

Method for embedding reversible watermark in digital image and method for extracting reversible watermark from digital image

The invention relates to a method for embedding a reversible watermark in a digital image and a method for extracting the reversible watermark from the digital image, and belongs to the field of information technology. The method for embedding the reversible watermark comprises the following steps of: dividing a carrier image and establishing a location mark sequence LMC, and dividing all pixels into three parts of I1, I2, and I3; embedding watermark in the pixel blocks in the I1 and I3; recording the lowest effective bit in the I1 into a sequence C, and using the LMC to replace the lowest effective bit in the I1; and finally, embedding the sequence C into an embeddable pixel block in the I2. The method for extracting the reversible watermark comprises the following steps of: dividing the carrier image and extracting the location mark sequence LMC; then dividing the pixel blocks into three parts of I1, I2, and I3; performing reverse transformation on the pixel blocks in the I2 according to the LMC to obtain an original pixel value sequence C; replacing the lowest effective bit in the I1 by the value in the sequence C; and finally, performing reverse transformation on the pixel blocks in the I1 and I3 according to the LMC to acquire an original pixel value and embedded watermark information. The method for embedding the reversible watermark in the digital image and the method for extracting the reversible watermark from the digital image improve the embedding capacity and do not need the original images during extraction.
Owner:PEKING UNIV

Fusion method of SAR (Synthetic Aperture Radar) images and visible light images on the basis of NSCT (Non Subsampled Contourlet Transform)

The invention relates to a fusion method of SAR (Synthetic Aperture Radar) images and visible light images on the basis of NSCT (Non Subsampled Contourlet Transform). The fusion method is characterized by comprising the following steps of: firstly, carrying out NSCT decomposition on the SAR images and the visible light images respectively; then adopting different fusion rules to carry out fusion treatment on NSCT low-frequency and high-frequency subband coefficients, wherein according to the decomposition coefficient characteristics of noise and signals in an NSCT domain, carrying out hard-threshold denoising on the NSCT high-frequency subband coefficient of the SAR images under the maximum decomposition scale, then respectively adopting different fusion rules to carry out fusion processing on the NSCT high-frequency subband coefficient under the maximum decomposition scale and other decomposition scales by adopting the coefficients with threshold processing as the basis; and finally,carrying out NSCT reverse transformation on the fused NSCT coefficients and obtaining fused images. The fusion method takes denoising as the basis of the fusion rule design, considers noise suppression while fusion treatment is carried out, is simple and easy to operate, can be used for obtaining a good fusion effect and is especially more applicable to the SAR images and the visible light imageswith serious spot and noise pollution.
Owner:海安县晋宏化纤有限公司 +1

Natural image noise removal method based on dual redundant dictionary learning

The invention discloses a natural image noise removal method based on dual redundant dictionary learning, aiming at mainly solving the problem that texture details are easy to lose in the existing natural image noise removal method. The natural image noise removal method based on dual redundant dictionary learning comprises the following steps: (1) inputting an image Y to be subjected to noise removal; (2) unfolding the image Y to be subjected to noise removal under a multi-scale redundant stable wavelet dictionary R to obtain coefficient components betaj of the image Y on different scales, wherein j is 1, 2,... and N; (3) initializing each variable to make a dictionary Dj be a redundant dictionary DCT, and updating atoms and corresponding coefficient matrixes of the dictionary Dj by adopting the KSVD algorithm; (4) calculating the estimation value of the noise removal results of all the coefficient components betaj; and (5) carrying out multi-scale redundant reverse transformation on all the coefficient components betaj subjected to noise removal to obtain the noise removal result of the image Y to be subjected to noise removal. Compared with the existing classical noise removal method, the natural image noise removal method based on dual redundant dictionary learning can better keep the texture detail information in the image to be subjected to noise removal and can be used for natural image noise removal.
Owner:XIDIAN UNIV

Multiple wave suppression method based on dual parabolic Radon transformation

The invention discloses a multiple wave suppression method based on dual parabolic Radon transformation. The method includes the steps that a pre-stack CMP trace gather is processed, an objective function is established, positive Radon transformation is performed on the pre-stack CMP trace gather, one-time reflected waves and multiple waves are separated in the Radon area, and data of the one-time reflected waves are estimated. The method solves the problems that an existing multiple wave attenuation technology based on convectional Radon transformation can not simulate AVO features of seismic data, the false phenomenon is generated in the positive transformation, the smearing exists, the distortion of the amplitude of the one-time reflected waves happens and leakage of the amplitude is caused in the reverse transformation, transformation of the shape of the seismic same-phase axis and the amplitude can be achieved in the Radon area, the movement features and the AVO features of seismic data can be separated better in the Radon area, the false phenomenon generated in the positive transformation process is weakened, accurate restoring of energy of the one-time reflected waves is achieved, the AVO features of the seismic data are protected, and the subsequent seismic inversion and explanation reliability is improved.
Owner:CHINA UNIV OF PETROLEUM (EAST CHINA)

Wind speed modeling method for large-sized wind power plant in mountainous area

The invention discloses a wind speed modeling method for a large-sized wind power plant in a mountainous area. The method comprises: 1, sampling historically recorded wind speed of the wind power plant, and calculating parameters c and k of wind speed Weibull distribution of each fan group of the wind power plant; 2, calculating a rank correlation coefficient Rho Rr of each fan group in the wind power plant, and constructing a historical wind speed rank correlation coefficient Rr of the wind power plant; 3, calculating related wind speed normal Copula functions of the wind power plant to obtain a joint probability distribution function, defined in the specification, of modeled and predicted wind speed with correlation, and edge probability distribution functions u1 to un of wind speed of fan groups; and 4, performing equiprobable reverse transformation of the Weibull distribution parameters c and k on the edge probability distribution functions of the wind speed of the fan groups to realize wind speed prediction. According to the method, the technical problem that a characteristic that wind speed in a wind power plant has correlation cannot be truly and effectively reflected, electric power distribution and safety operation of a power system are influenced due to direct influence of the correlation of the wind speed in the wind power plant on output of the wind power plant, and the like in the prior art are solved.
Owner:POWER GRID PLANNING RES INST OF GUIZHOU POWER GRID CO LTD

Initial estimation improvement-based image super-resolution reconstruction method

The invention belongs to the fields of image processing and computer vision detection, and relates to an initial estimation improvement-based image super-resolution reconstruction method. The method comprises the steps of shooting similar but not completely same image sequences of a same scene by utilizing a camera, calculating transformation matrixes, relative to a reference image, of other images by taking a first image as the reference image, reserving sub-pixel displacement between the images, performing reverse transformation on the image sequences, and interpolating and amplifying the reference image by 4 times to serve as initial estimation of a high-resolution image; and correcting the initial estimation by utilizing the image sequences subjected to the reverse transformation to obtain a corrected high-resolution image, performing iterative correction on each pixel point of the image by utilizing a convex set projection algorithm until an iterative condition is met, and finally obtaining a reconstructed high-resolution image. According to the method, the pixels of the high-resolution image are properly improved before being subjected to projection correction, so that mean square errors of reconstruction are reduced and higher image reconstruction quality is achieved.
Owner:DALIAN UNIV OF TECH

Method for channel estimation

The invention discloses a channel estimation channel, which belongs to the technical field of digital information transmission. The method comprises the following steps: removing intersymbol interference and noise from linear convolution of data of the previous frame and channel impulse response to obtain novel linear convolution; calculating the pseudo random sequence of the current frame and the linear convolution for initial channel estimation; reconstructing the linear convolution of the current frame; respectively transforming the pseudo random sequence of the current frame and the reconstructed linear convolution; carrying out reverse transformation of the ratio after transformation to obtain novel channel estimation; and accumulating the iteration times, and using the novel channel estimation as the initial channel estimation for further iteration if the iteration times does not reach the preset maximal value, or else, setting the novel channel estimation as the final channel estimation. The channel estimation method can acquire more accurate channel estimation, eliminate intersymbol interference caused by multi-path channels and reduce the processing complexity for channel estimation and balance a of multi-carrier or single carrier transmission system based on pseudo random sequence filling.
Owner:TSINGHUA UNIV

Transmission method for lowering interference between code sequences and code sequence multiplexing in CDMA system

The invention relates to a transmission method for reducing interference and code sequence multiplexing among code sequences in a code division multiple access system. The transmission method relates to the technical field of communication and solves the problems of the interference and the insufficient code sequences in the code sequences in the existing CDMA system, the steps are as follows: a data source is sent to a transformation module at a transmitter end after the digital modulation and the PN source spread spectrum, the transformation module carries out the 4-th weighted fractional Fourier transform of data under the control of a parameter Alpha, and the data after the digital carrier modulation is further sent to a channel for transmission after the upper frequency conversion; the data after the lower frequency conversion is sent to a reverse transformation module at a receiver end, a CDMA signal after the spread spectrum is obtained after carrying out the demodulation, the dispread spectrum and the 4-th weighted fractional Fourier transform under the control of the parameter Alpha in the reverse transformation module, and then the CDMA signal is output to the outside through the digital demodulation work. The use of the method can reduce the interference among CDMA users and improve the capacity of the system; furthermore, the optimization and the reuse of the code sequences of the CDMA system can be realized under the condition of not occupying additional spectrum, time and code resources.
Owner:HARBIN INST OF TECH
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