31 results about "Coherence factor" patented technology

A set of NxM signals are acquired from an object, where N is the number of array elements and M corresponds to variations in data acquisition and / or processing parameters. The parameters include transmit aperture functions, transmit waveforms, receive aperture functions, and receive filtering functions in space and / or time. A coherence factor is computed as a ratio of the energy of the coherent sum to the energy of the at-least-partially incoherent sum of channel or image signals acquired with at least one different parameter. Partial beamformed data may be used for channel coherence calculation. For image domain coherence, a component image is formed for each different transmit beam or receive aperture function, and a coherence factor image is computed using the set of component images. The coherence factor image is displayed or used to modify or blend other images formed of the same region.

The present invention relates to an encoding method processing video object planes (VOPs) of I, P or B type and including a dynamic allocation of said VOPs. According to said method, for each input frame a preliminary forward motion estimation is carried out between current and previous frames. Current and previous motion fields are then used to evaluate a coherence factor, expressed as connected to the sums of local differences within current and previous motion field. According to the value of the coherence factor with respect to an empirically determined threshold, a decision is finally taken on the type of the frame to be coded.

There is provided a method for correcting a photo mask, which allows the difference between a test mask and a corrected mask with respect to an error of line width depending on coarse / dense pattern to be decreased when the photo masks are corrected by optical proximity effect correction.The present method is consisted of: producing a test mask which acts as a mask for extracting process model for applying an optical proximity effect correction method (s1); transferring and measuring the dimensions of the transferred pattern using the test mask (s2 and s3); obtaining a function model (referred to as process model) of which a simulated result of the transferred pattern of a mask pattern of the photo mask using a function model matches the measured result (s4); obtaining a mask pattern of which a transferred pattern matches a designed pattern using said process model and creating mask data in accordance with the obtained mask pattern (s5); producing a corrected mask in accordance with the created mask data (s5); and setting an exposing condition where an OPE characteristic becomes flat with respect of wide and narrow pitches by adjusting at least one of a numerical aperture (NA) and a coherence factor (σ) of an exposing device when the corrected mask is transferred.

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.