34results about How to "Imaging results are good" patented technology

The invention discloses an MEG system and method based on an atom magnetometer. A design scheme of an EMG capable of being freely detached in practical operation is provided to insulate heat and prevent extra magnetic field interference during the practical use. A gyroscope is added to all or representative magnetometers to acquire magnetometer directions; a great system is caused when plenty of magnetometer arrays are added to a brain magnetic hat; due to technical reasons and economic factors, a method for integrally processing optical signals is provided, so MEG spatial resolution can be improved, technological difficulties can be reduced and great economic effects can be achieved.

The invention discloses a motion compensating method applicable to high-speed-mobile-aircraft-mounted SAR (synthetic aperture radar) imaging. The motion compensating method includes: establishing a motion error model applicable to high-speed-mobile-aircraft-mounted SAR imaging according to characters of high-speed-mobile-aircraft-mounted SAR imaging; on the basis of the model, analyzing influence on SAR imaging from an inertial navigation error; after distance-direction processing and initial direction Deramp processing are finished, utilizing inertial navigation information and combining with Doppler frequency estimation to obtain residue Doppler frequency modulation information of an echo, utilizing the obtained residue Doppler frequency modulation information to construct a corresponding compensating function to reasonably compensate an error phase, and thereby focusing quality of high-speed-mobile-aircraft-mounted SAR images is effectively improved.

The invention provides a dual-station SAR receiver kinematic error compensating method based on navigation satellite signals. The method includes the steps of establishing a Doppler rate and kinematicerror relation model, estimating and compensating for receiver method planar kinematic errors, and estimating and compensating for receiver cruise direction kinematic errors. The method has the advantages that according to the structural characteristics of a dual-station SAR based on the navigation satellite signals, the method based on the instantaneous Doppler rate is put forward to correct thekinematic errors of a receiving platform; the real model of three-dimensional movement errors is sufficiently considered in the method, and the kinematic error estimating and compensating can be effectively conducted; no interpolation or iteration treatment needs to be conducted in the method, the processing efficiency is high, and a good imaging result is obtained.

The invention discloses a femtosecond differential optical Kerr gate and an imaging device and method based on the optical Kerr gate. A probe light path is provided with a target to be detected, a scattering medium, the femtosecond differential optical Kerr gate and two single-pulse triggering CCDs in sequence, wherein the femtosecond differential optical Kerr gate is composed of a polarizer, an optical Kerr medium, a first beam splitting piece, two quarter-wave plates and two analyzers. The polarization direction of the polarizer is the same as the polarization direction of femtosecond detecting pulse light, the positive heterodyne angle ranging from 2 degrees to 5 degrees is formed by the polarization direction of one analyzer and the polarization vertical direction of the polarizer, and the negative heterodyne angle ranging from 2 degrees to 5 degrees is formed by the polarization direction of the other analyzer and the polarization vertical direction of the polarizer. A switching light path is provided with a half wave plate and an optical delay line. The femtosecond switching pulse light coincides with the femtosecond probe pulse light in the optical Kerr medium. A positive heterodyne single-pulse gating image and a negative heterodyne single-pulse gating image are obtained on the two single-pulse triggering CCDs respectively, subtraction is carried out on the two images to obtain a femtosecond differential optical Kerr gate single-pulse gating image of the target to be detected. The single-pulse imaging with the high signal to noise ratio is achieved, and the femtosecond differential optical Kerr gate and the imaging device and method based on the optical Kerr gate have the advantages that the time resolution, the image contrast and the system resolution are high.

The invention relates to an FPGA (field programmable gate array) imaging system for ultra wideband microwave target detection, in particular to an FPGA imaging system for ultra wideband microwave target detection, which aims at completing the comprehensive control on an imaging input/output system. The FPGA imaging system is provided with a top control module and an input/output port, so as to completely realize the FPGA data input and image output process of the three-dimensional imaging by ultra wideband detection. The FPGA imaging system for ultra wideband microwave target detection adopts the technical scheme that the FPGA imaging system comprises a transmission antenna, a receiving antenna, a signal processing module, a time delay calculation module, a focusing module and an image reconstruction module, wherein the transmission antenna and the receiving antenna are arranged at fixed locations; the transmission antenna is used for sending an ultra wideband microwave signal, and the receiving antenna is used for receiving the ultra wideband microwave signal reflected by a tested tissue. The FPGA imaging system is mainly applied to the design and manufacturing of detection, imaging and medical treatment equipment.

The invention discloses a positioning device and a positioning method of a handheld imaging system. The imaging system is provided with at least three groups of laser diodes, each laser diode group comprises at least two laser diodes, the included angle between laser rays emitted by the two laser diodes of each group is regulated, the intersection point of each laser diode group is located on a preset imaging surface, three or more groups of laser diodes are irradiated to an imaged object, the distance and angle of the imaging system relative to the imaged object are regulated, and when the two laser rays of each group are intersected on the imaged object to become a point, the fact that the distance and angle between the imaging system and the imaged object reach preset values is indicated, and the best imaging result is obtained.

The invention provides an inverse synthetic aperture radar imaging method combining a gate unit and transfer learning, and the method comprises the steps that a full convolutional neural network FCNN is constructed through employing a conventional convolution layer, an activation function layer, a batch normalization layer, a maximization pooling layer, and the like; a plurality of paths are established by utilizing jump connection SKs in the FCNN and are used for directly transmitting network shallow feature representation OFRs to a network reconstruction layer; secondly, the gate unit is further introduced into the FCNN to form a G-FCNN, and a transfer learning strategy TL is adopted to ensure that the performance of the G-FCNN is optimal; and then large-scale radar training data is constructed by using electromagnetic simulation software for pre-training the G-FCNN, and network layer parameters in the pre-trained G-FCNN are finely adjusted by using small-scale actually measured radar data to obtain optimal network parameters for a target imaging task. The inverse synthetic aperture radar imaging method is superior to an existing ISAR imaging method based on the convolutional neural network.

The present invention discloses an image processing technology-based passive millimeter wave radiation imaging system distance measurement method. The method includes the following steps that: two sets of passive millimeter wave radiation imaging systems of which the parameter settings are consistent are arranged on the same straight line sequentially relative to a target scene according to a passive distance measurement model; the same target scene is imaged through the two sets of passive millimeter wave radiation imaging systems, so that corresponding measurement imaging data are obtained; three characteristic points with the highest target scene matching degree are extracted from two groups of measurement imaging data through using a surf matching algorithm; and the area of connected regions of the characteristic points is calculated, and a target distance can be calculated through the passive distance measurement model. According to the distance measurement method of the invention, the passive millimeter wave radiometers are adopted to carry out imaging, and therefore, compared with photoelectric and infrared passive distance measurement methods, the distance measurement method of the invention can obtain better imaging results and higher distance measurement accuracy in harsh environments such as cloud, fog, battlefield smoke and so on.

The invention discloses a DSN-based high-resolution two-dimensional ISAR imaging method. The method solves the problems that the 2D-FISTA algorithm has openness of optimal regularization term coefficient selection, a CV-DNN network lacks theoretical support and needs high space and time complexity, and DSN cannot solve the problems of main lobe width, high sidelobe and the like of an RD image. Themethod comprises the following implementation steps: obtaining wave number domain echoes in a two-dimensional matrix form and wave number domain echoes in a one-dimensional vector form of ISAR two-dimensional scattering point distribution; solving a one-dimensional vector form and a two-dimensional matrix form of two-dimensional scattering point distribution; building a DSN network; setting a loss function; performing DSN network training; and completing the ISAR high-resolution two-dimensional imaging based on the DSN. Based on a sparse signal reconstruction theory, an SALSA algorithm is constructed into a deep network, high-resolution two-dimensional ISAR imaging is realized, an ISAR image with good focusing and a clean background is obtained, and the method can be used for efficientlyperforming high-resolution two-dimensional ISAR imaging in batches in complex electromagnetic environments with target echo defects, noise and the like.

The invention discloses a low-noise least square reverse time migration method. The method comprises the following steps: establishing a least square reverse time migration function; a sparse constraint term is added to a least square reverse time migration function to suppress noise, and a target function is obtained after sparse constraint of the Cauchy constraint term; and determining parameters of an objective function of the least square reverse time migration function after sparse constraint of the Cauchy constraint term, optimizing the gradient of the objective function, and performing minimization solution on the least square reverse time migration function by adopting a precondition nonlinear conjugate gradient method. According to the low-noise least square reverse time migration method disclosed by the invention, a new method for determining regularization parameters and hyper-parameters in Cauchy terms is provided, a better imaging result can be obtained, the convergence speed of inversion can be increased, and a method for determining step length is provided for an objective function containing Cauchy constraint terms.

The invention discloses a maximum contrast space-variant phase self-focusing ISAR imaging method. The method includes acquiring the ISAR echo data, and dividing the azimuth corresponding echo data and the distance corresponding echo data of the ISAR echo data to obtain M azimuth units and N distance units; determining the total number of slow time, and then obtaining the final focuse image of the ISAR echo data; calculating the final focus image contrast of the ISAR echo data, taking the final focus image contrast of the ISAR echo data as a cost function, respectively calculating the distance space-variant quadratic phase error coefficient estimate value of the nth distance unit, the azimuth space-variant phase error coefficient estimate value of the mth azimuth unit, and the quadratic phase error coefficient estimate value for the kth constant, and calculating the focus images of the mth azimuth unit and the nth distance unit; and obtaining the maximum contrast space-variant phase self-focusing ISAR image.

The invention discloses a detachable bionic eyeball model and an imaging method thereof. The detachable bionic eyeball model comprises a guide rail, a fixing base is fixedly installed at the upper endof the guide rail, a first supporting rod is fixedly installed at the upper end of the fixing base, an eyeball model part is fixedly installed at the upper end of the first supporting rod, and a model cover is arranged at the front end of the eyeball model part; an adjusting piece is arranged in the model cover and the eyeball model piece together, a first sliding block is slidably connected to the left portion of the guide rail, a second supporting rod is fixedly installed at the upper end of the first sliding block, a display plate is fixedly connected to the upper end of the second supporting rod, and a character piece and a light source are fixedly installed at the right end of the display plate; and the right part of the guide rail is slidably connected with a driving piece. According to the detachable bionic eyeball model and the imaging method thereof, a good demonstration effect can be achieved on adjusting force, the influence of eye axis changes on vision can also be demonstrated, and the eye protection consciousness is improved; and the imaging method is diversified, so that an optimal imaging result is convenient to select.