5 results about "Perfect reconstruction" patented technology

The invention discloses an integral coefficient design method for a two-channel lattice orthogonal filter bank. According to the method, on the basis of direct quantization of continuous optimal coefficients, a quantization sequence criterion is provided, and descending sorting is carried out according to the sensitivity of lattice coefficients to serve as a quantization sequence. Secondly, using a low-pass analysis filter frequency point in a stop band range as a target function for quantizing a perfect reconstruction orthogonal filter bank, using a directly quantized lattice coefficient as an algorithm initial value, using Gurobi to optimize and solve, and minimizing the target function f for each frequency point; and performing first-order Taylor approximation on the target function to obtain a coefficient error value, and updating a lattice coefficient value based on a quantization sequence to complete lattice coefficient discretization. According to the method, the problem that the stop-band attenuation performance and the frequency selectivity are insufficient due to coefficient mantissa truncation and rounding in an existing quantization method is solved, and the obtained integral coefficient meets the perfect reconstruction characteristic of the two-channel lattice type orthogonal filter bank.

The invention discloses a high-speed data capture method based on a TIADC radio frequency direct sampling and DDC combined processing architecture, and the method comprises the steps: firstly collecting a full-band sweep frequency signal through a TIADC, and obtaining multi-channel parallel sampling data at different frequency points; performing wide linear inverse filter inversion based on multiple paths of parallel sampling data under different frequency points, designing a perfect reconstruction filter, a low-pass filter and a flatness filter at the same time, and combining the filters into an integrated correction filter through convolution; and finally, down-conversion and error correction processing are completed at a radio frequency signal acquisition front end based on TIADC radio frequency direct sampling and DDC combined processing architecture, high-speed data acquisition of input signals is realized, errors and distortion introduced by channels are suppressed, and high-quality high-frequency low-rate data streams are output to a subsequent digital signal processing module.

The invention discloses a golden section-secant method optimization design method for a two-channel lattice filter. The method comprises the following steps: firstly, designing an odd-order two-channel filter which meets a linear phase and can achieve perfect reconstruction; secondly, a secant method and a golden section method are adopted for optimization, a set of good initial traditional filter bank coefficients are obtained and converted into lattice coefficients through a lattice coefficient conversion formula, even term coefficients are all returned to zero, and therefore the lattice filter bank has the perfect reconstruction characteristic; the method comprises the following steps: firstly converting a lattice coefficient into a plurality of lattice coefficients, constructing an objective function, then optimizing the converted lattice coefficient by adopting a secant method and a golden section method, solving the objective function by utilizing an SQP algorithm in each optimization iteration process, and finally obtaining a group of optimal lattice coefficients. According to the method, the performance of the converted filter bank can be effectively improved, the linear phase is met, and meanwhile the perfect reconstruction characteristic is met.

This invention relates to the field of filter technology, and particularly to a design method, system, device, and medium for a quasi-completely reconstructed filter bank. The method first uses a generalized monotonic asymptotically saturated function as the initial value of a prototype filter, substituting it into the filter bank model for optimization to obtain a baseline fully reconstructed prototype filter. Then, a transition band adjustment parameter is introduced to perform an analytical mapping transformation on the amplitude-frequency response of the baseline fully reconstructed prototype filter, resulting in a fully reconstructed prototype filter with optimized transition band. Finally, combined with a determined number of filter bank channels and the polyphase decomposition length of the prototype filter, a quasi-completely reconstructed prototype filter is obtained through frequency domain sampling and transformation processing, which is then modulated to obtain a quasi-completely reconstructed filter bank. This method, by introducing a generalized monotonic asymptotically saturated function as the initial value of the prototype filter and combining it with the analytical mapping mechanism of the transition band adjustment parameter, significantly improves stopband attenuation performance and increases the efficiency of prototype filter coefficient generation while ensuring quasi-complete reconstruction.

The invention discloses a complex-valued wavelet depth-of-field fusion method and device, a storage medium and a program product. The method comprises the steps of collecting an original image, converting the image into a complex value wavelet domain, fusing the image according to an amplitude maximum principle and recording a layer number, using a highest frequency sub-band layer number to back-source construct a texture image, fusing the texture image, and using a low frequency sub-band cascade of the fused texture image to replace a low frequency sub-band of a preliminary fused image. And inverse complex value wavelet transform is carried out on the corrected fusion image. According to the method, the low-frequency substrate is corrected on the premise that error-prone high frequency is not directly carried, low-frequency drift, halation and local contrast abnormity caused by the fact that perfect reconstruction conditions are not met in traditional complex value wavelet fusion are relieved, meanwhile, the detail sharpness is kept, and the method is suitable for microscopic imaging, macro shooting and industrial detection.