31 results about "Coherence factor" patented technology

The invention discloses a multi-baseline PolInSAR vegetation parameter inversion method considering the time decoherence factor, comprising the following steps: step 0, introducing the time decoherence factor into the RVoG model, and obtaining the RVoG extended model taking the time decoherence factor into consideration; step 1. Perform preprocessing and polarization interferometry on the multi-baseline polarization interferometric SAR image of the vegetation to obtain multi-baseline multi-polarization complex coherence coefficient observations; step 2. Set and calculate the initial value of the vegetation parameter inversion of the RVoG extended model ; Step 3, select one of the N baselines as a reference baseline, and consider that it does not have the influence of time decoherence factors; Step 4, match the observed values ​​with the RVoG extended model, and construct the observation equation; finally, according to the parameters obtained above value, using a nonlinear iterative algorithm for vegetation parameter inversion. The invention can improve the accuracy of vegetation parameter inversion and is easy to realize.

The invention discloses a coherent factor adjusting system in a deep ultraviolet lithography lighting system. The coherent factor adjusting system comprises a converging lens group, light-homogenized robs, a control device and a lighting field, wherein the converging lens group is arranged on a lighting light path of the lighting system and is responsible for converging the light to an appointed position; the light-homogenized robs are arranged on the light path of the converging lens group of the system; the light converged by the converging lens group enters through incidence ends of the light-homogenized robs and exit through exit ends of the light-homogenized robs; the control device is used for fixing a plurality of light-homogenized robs with different aperture ratios, and is provided with a rotating shaft which is parallel to the optical axis of the lighting system; the control device rotates around the rotating shaft so as to adjust the positions of the light-homogenized robs, so that appointed light-homogenized robs are put in the light path of the lighting system to join in adjusting coherent factors of the lighting system; the control device is driven by a high precision rotary table; relay lenses are arranged on the exit light path of the light-homogenized robs; and the lighting field is arranged on the exit light path of the relay lenses. By utilizing the coherent factor adjusting system, the coherent factors of a system can be adjusted, or the design complexity of a varifocus lens can be simplified, so that the purposes of simplifying the structure and reducing the cost are achieved.

The present invention discloses a high-seed super-resolution MIMO (multi input multi output) array imaging method. The method includes the following steps that: step 1, data sampling is performed on an MIMO array; step 2, an MIMO-RMA (range migration algorithm) is utilized to complete three-dimensional reflectivity image reconstruction; step 3, the acceleration of the MIMO-RMA is utilized to calculate a coherence factor; and step 4, the coherence factor corrects a reflectivity three-dimensional image. According to the imaging algorithm of the invention, reflectivity incoherent power is simplified by rearranging echo data, the acceleration of the MIMO-RMA is utilized to calculate the coherence factor, and the calculation speed of the coherence factor is greatly increased in combination with a parallel algorithm; super-resolution performance is balanced through controlling parameters alpha and beta according to a defect that the coherent factor suppresses weak scattering points, and at the same time, the stability of the algorithm is not affected; and the coherence factor is utilized to correct the reconstructed three-dimensional image, so that sidelobe and ground noises can be effectively suppressed, and higher resolution can be achieved.

The present invention discloses a wave number domain coherence factor-based high-speed super-resolution stagnation point scanning imaging method. The method specifically includes the following steps that: step 1, an antenna receives and records echo signals; step 2, a reflectance function is calculated; step 3, a coherence factor is calculated; and step 4, the coherent factor is used to correct an image. According to the algorithm of the invention, the concept of the space-domain coherence factor is expanded to the wave number domain, and a distance migration imaging algorithm is used in combination, and therefore, the method can have real-time imaging capacity; and if combined with a parallel algorithm, the method can further improve efficiency. Compared with a traditional distance migration imaging algorithm and back-projection imaging algorithm, the wave number domain coherence factor-based high-speed super-resolution stagnation point scanning imaging method has higher resolution and lower side lobe and can effectively suppress base noises. Since parameters alpha and beta are adopted to adjust the performance of the coherence factor, and the suppression of the coherence factor on side lobe and weak scattering points can be balanced, and therefore, performance is stable.

The invention discloses a method for self-adaptation ultrasonic imaging of a spatio-temporally smoothed coherence factor type. The method comprises the following steps that (1) beam forming preprocessing is conducted; (2) beam forming processing is conducted, wherein beam forming processing comprises the steps that delayed focusing is conducted on each channel received signal, a coherence factor value of the spatio-temporally smoothed coherence factor type is calculated according to the channel received signal after delayed processing, and weighted processing is conducted on the coherence sum of the received signals through coherence factors so that beams of each scanning line can be obtained and output; (3) beam forming post-processing is conducted, wherein beam forming post-processing comprises the steps that envelope detection, logarithm compression, scanning conversion and display are conducted on the scanning lines. According to the method for self-adaptation ultrasonic imaging of the spatio-temporally smoothed coherence factor type, side lobe can be restrained, sound disorder is reduced, the contrast ratio of an image is improved, an artifact is remarkably eliminated, the imaging quality is improved, the calculation complexity is low, and the method is easy to achieve in hardware.