Abstract:
A method for reconstructing surface from a point cloud includes following steps: (a) extracting skeletal curves from an input point cloud; (b) editing the extracted skeletal curves, and assigning sweeping path; (c) obtaining sliced point clouds along the edited skeletal curves, and fitting a closed NURBS curve according to the sliced point clouds; (d) reconstructing the point cloud to get generalized cylinders along the assigned sweeping path, according to the closed NURBS curves; (e) merging the generalized cylinders into a single surface, and smoothing intersections of the generalized cylinders so as to reconstruct surface from the point cloud. The invention further relates to a system for reconstructing surface from a point cloud. The invention can reconstruct the surface with high accuracy by the minimum interactions, and can deal with point cloud data having missing region caused by occlusion. In addition, the invention can achieve high reconstruction quality and fine controllability.
Abstract:
Disclosed is a magnetic resonance rapid parameter imaging method and system. The method comprises: obtaining a target undersampled magnetic resonance signal (S10); obtaining prior information of a parameter model (S20); performing sequence reconstruction of a target image according to the undersampled magnetic resonance signal and the prior information to obtain a target image sequence (S30); and substituting the target image sequence into the parameter estimation model to obtain object parameters and to generate parametric images (S40).
Abstract:
Disclosed is a method for automatically optimizing point cloud data quality, including the following steps of: acquiring initial point cloud data for a target to be reconstructed, to obtain an initial discrete point cloud; performing preliminary data cleaning on the obtained initial discrete point cloud to obtain a Locally Optimal Projection operator (LOP) sampling model; obtaining a Possion reconstruction point cloud model by using a Possion surface reconstruction method on the obtained initial discrete point cloud; performing iterative closest point algorithm registration on the obtained Possion reconstruction point cloud model and the obtained initial discrete point cloud; and for each point on a currently registered model, calculating a weight of a surrounding point within a certain radius distance region of a position corresponding to the point for the point on the obtained LOP sampling model, and comparing the weight with a threshold, to determine whether a region where the point is located requires repeated scanning. Further disclosed is a system for automatically optimizing point cloud data quality.
Abstract:
Disclosed are a method and system for dividing a plant organ point cloud. According to information about lamina point cloud blocks and stem point cloud blocks in a previous adjacent point cloud frame of a point cloud frame to be divided and a flatness feature of a data point of the point cloud frame to be divided, a point cloud of the point cloud frame to be divided is divided into lamina point cloud blocks and stem point cloud blocks; taking the adjacent point cloud frame as a reference to divide the point cloud frame facilitates the divided organ in maintaining the consistency of time and space between adjacent point cloud frames, and improves the accuracy of plant organ division. When a new lamina point cloud block or a stem point cloud block is discovered, the point cloud in the point cloud frame before the point cloud block to be divided is redivided through tracking back; when redividing, according to information about the lamina point cloud blocks and the stem point cloud blocks in the next adjacent point cloud frame, the point cloud frame to be redivided is divided; and the redivision during tracking back facilitates extracting, from the point cloud frame, a new lamina point cloud block or a stem point cloud block which was not discovered in the previous division process, thereby further improving the accuracy of plant organ division.
Abstract:
Provided are an image restoration method and device. The method comprises: processing image blocks, which are initially registered, to acquire connection curves among the image blocks; constructing an ambient field of images to be restored by means of the connection curve; by minimizing energy of the connection curve in the ambient field, registering the image blocks; and performing image filling on the registered image blocks to acquire a restored image. The device comprises: a processing unit used for processing the image blocks, which are initially registered, to acquire the connection curve among the image blocks; an ambient field construction unit used for constructing the ambient field of the image to be restored by means of the connection curve; a registering unit used for registering the image blocks by minimizing the energy of the connection curve in the ambient field; and a filling unit used for performing image filling on the registered image blocks to acquire the restored image. The present invention can be applied to restore any damaged image and improve the accuracy.
Abstract:
The present invention relates to a magnesium alloy material, which is an in situ magnesium hydroxide nanosheet layer modified magnesium alloy. The material is prepared from a magnesium alloy through a hydrothermal reaction under alkaline condition. The protective effect of the in situ formed magnesium hydroxide nanosheet layer structure results in remarkably enhanced corrosion resistance of the magnesium alloy, meanwhile the biocompatibility can also be significantly improved since the release rate of magnesium ion can be significantly reduced. In addition, the two-dimensional nanolayer structure has a non-releasing physical antibacterial property depending on contact. Therefore, the magnesium alloy material according to the present invention has an extremely great application prospect in the field of medical implant.
Abstract:
The invention relates to a directional coupler, coupling high power and low power is used to replace existing two high-power directional couplers, thus reducing the cost and reducing the insertion loss of high-power radio frequency channels. The directional coupler cooperates with a control conditioning board, a splitter, a multi-path radio frequency power amplifier and a combiner to form the radio frequency power amplifier system, and the system is connected to a spectrometer; on one hand, by using a standard signal output by the spectrometer and a feedback signal of the directional coupler, nonlinearity caused by the power amplifier is corrected to achieve magnet-free linear radio frequency power amplification and anomaly protection; and on the other hand, the spectrometer can be used for monitoring the output power of the directional coupler and monitoring antenna matching, so as to provide dual protection for the radio frequency power amplifier system.
Abstract:
A method for high-throughput TAG to TAA conversion on the genome are provided. The method comprises the following steps: co-transfecting a gRNA array pool or a transcription product thereof, a plasmid containing an mCherry-inactivated eGFP reporter molecule and an sgRNA plasmid for editing and activating eGFP in a stable cell of an inducible base editor; or by transfecting an 43-all-in-one expression vector or a transcription product thereof to cells with stable inducible base editor, high-flux TAG to TAA conversion in single cells is realized, and through multiple cyclic operations, almost all TAG to TAA conversion in the whole genome of cells of common model organisms can be realized.
Abstract:
Provided are a transgenic animal model, a method for constructing same, and use thereof. An Axin1flox/flox transgenic mouse is used to mate with an Agc1-CreER transgenic mouse to produce an Axin1+Agc1ER condition knockout mouse. Then by means of tamoxifen induction, the Axin1 expression in the Axin1+Agc1ER condition knockout mouse is down-regulated, and a disease combined model with the pathological characteristics of “growth plate chondrocyte hypertrophy, heterotopic ossification and articular cartilage degeneration of knee joints” is successfully established. The model is similar to clinically related pathological features, and can be used for systematically studying the pathogenesis of growth plate chondrocyte hypertrophy, heterotopic ossification and osteoarthritis and further screening for drugs for treating related diseases.
Abstract:
A microfluidic system, including: a container, an ultrasound transmitter assembly, and a phononic crystal plate. The container is configured to accommodate a solution containing microparticles. The ultrasound transmitter assembly is configured to transmit ultrasonic waves to the phononic crystal plate, where the ultrasonic waves have a frequency which is the same as a resonance frequency of the phononic crystal plate. The phononic crystal plate is placed in the solution, and configured to generate a local acoustic field on a surface of the phononic crystal plate under excitation of the ultrasonic waves, and induce an acoustic microstreaming vortex to generate an acoustic streaming shear stress on the microparticles. The phononic crystal plate defines therein cavities, the respective cavities are arranged periodically in the phononic crystal plate, and all the respective cavities are filled with gas.