7 results about "Diffraction model" patented technology

The invention relates to a convolutional neural network hologram generation method based on unsupervised learning, and belongs to the field of artificial intelligence technology and computer-generated holography. Comprising the following steps: incorporating a physical diffraction model into an unsupervised learning convolutional neural network, firstly inputting a target image into the SCLSK-Net network, outputting a predicted phase by a coding part, introducing space and channel reconstruction convolution into the coding part of the network, reducing redundancy calculation, promoting learning of representative features, and then transmitting to a decoding part; a large-selectivity nuclear network is introduced in a decoding part, a space acceptance field is dynamically adjusted, ranging environments of various objects in different scenes are simulated, then transmission of a physical diffraction model is realized, and learning parameters can be automatically updated by reversely transmitting loss to an initial coding part; and through an attention mechanism and space channel reconstruction convolution, generation of a high-quality rapid computer-generated hologram is realized.

The application discloses an optical element subsurface defect detection method and system based on phase contrast digital holography, and belongs to the field of precision measurement technology; the system adopts annular Bessel beam Kohler illumination, utilizes polarization modulation technology and a specially-made polarization contrast ring to realize synchronous four-step phase shift high-speed quantitative phase measurement in a U-shaped light path; the method acquires complex amplitude through a polarization camera, compensates for resolution loss by using a self-supervision super-resolution reconstruction algorithm fused with a physical model; full-field and local inverse diffraction reconstruction is carried out based on angular spectrum diffraction theory, high-precision depth positioning is realized based on the diffraction light complex amplitude distribution characteristics as a focusing criterion; three-dimensional information representation of defects is realized in combination with an optical field scattering and diffraction model and a machine learning algorithm; the application can realize high-sensitivity, high-signal-to-noise ratio, real-time in-situ quantitative detection and three-dimensional reconstruction of submicron defects without significantly increasing the cost.

The invention discloses a method and a system for generating and executing an anti-interference flight strategy of a C2 link of an unmanned aerial vehicle, and particularly relates to the technical field of unmanned aerial vehicle communication. The method comprises the following steps: acquiring urban building material parameters and unmanned aerial vehicle flight parameters; based on the parameters, combining a free space path loss model, a Rice fading model and a blade peak diffraction model to construct an urban environment channel model; injecting same-frequency Wi-Fi interference and building reflection interference signals to calculate a signal to interference plus noise ratio; based on the signal to interference plus noise ratio, calculating the bit error rate and evaluating the anti-interference performance, and generating an anti-interference optimization scheme including frequency band switching and flight height adjustment; and controlling the unmanned aerial vehicle to execute the strategy. Aiming at the problems of Wi-Fi co-frequency interference, building shielding, glass curtain wall multipath reflection and the like in a complex urban environment, frequency band self-adaptive switching and flight height optimization are realized through multi-model joint simulation and dynamic strategy generation, the bit error rate is reduced, the anti-interference capability is improved, and the method has the advantages of being simple in structure and convenient to operate. And the communication reliability and the flight safety of the unmanned aerial vehicle in a complex urban environment are effectively guaranteed.

A focus adjustment method for acquiring an image of a surface of interest of a sample by a holographic imager includes the steps of:placing the sample including at least one reference object having a known shape and described by characterising parameters having at least position parametersacquiring an image and determining the position of the reference object with respect to the acquisition plane, by applying a light diffraction model involving the spatial parameters of the reference object estimated by approximating the appearance of the reference object in the holographic image acquired, anddetermining the position of the surface of interest with respect to the acquisition plane from a position of the reference object and focus adjustment of the image acquisition.

The invention discloses a resolution improvement limit derivation method. The method comprises the following steps: converting an echo signal into an echo signal matrix expression under a geometric diffraction model; echo vector probability distribution is obtained under the condition that preset noise is Gaussian complex noise, and an echo likelihood function is obtained according to the echo vector probability distribution; calculating a Fisher information matrix of the scattering center parameter; obtaining CRLB of the scattering center parameters according to the Fisher information matrix of the scattering center parameters; obtaining the minimum distance between the two scattering centers according to the pole phase difference of the two scattering centers under the pole model; obtaining the phase difference of two poles in the first sub-band and the phase difference of two poles in the double sub-bands according to the minimum distance between the two scattering centers; and obtaining a resolution improvement limit according to the phase difference minimum value of the two poles in the first sub-band and the phase difference minimum value of the two poles in the double sub-bands. The invention solves the problem that the existing resolution improvement limit is only suitable for a point scattering center and has a narrow application range.

The application discloses a double-sided achromatic superlens based on phase load balancing and a design method, and belongs to the technical field of micro-nano optics and computational imaging. The superlens comprises a transparent low-refractive substrate, a first structure layer located on the incident surface of the substrate and a second structure layer located on the emitting surface of the substrate; the first structure layer is a non-periodic phase type Fresnel zone plate, which is used for providing a basic focusing phase and pre-bending incident parallel light to the inside of the substrate; the second structure layer is an isotropic cylindrical nano column arranged in a square lattice, which is used for providing a residual focusing phase and a wide-band chromatic aberration compensation phase. Through the double-sided phase distribution balancing logic, the light deflection pressure is shared together, combined with the full-path scalar diffraction model, super-atom response calculation and end-to-end deep learning optimization, the bottleneck of low-refractive material in high-NA achromatic application is completely solved, and the micro-nano processing technology of large area and low cost is compatible.

The application discloses a design method of dihedral angle error of a single corner reflector, and the method comprises the following steps: calculating the variation range of a speed difference angle according to the orbital elements of a ranging target; constructing a far-field diffraction model based on the dihedral angle error compensation speed difference effect; inputting the parameters of the corner reflector and the ranging laser and the variation range of the speed difference angle into the far-field diffraction model as input conditions; performing far-field diffraction simulation on the corner reflector with dihedral angle error in the Fraunhofer formula in the far-field diffraction model to obtain corresponding far-field energy distribution; and calculating the optimal dihedral angle error of the corner reflector according to the far-field energy distribution. The design method of the dihedral angle error has strong universality and can be applied to various laser ranging scenes.