33 results about "Spatiotemporal encoding" patented technology

The invention relates to the field of computer vision and deep learning, in particular to a video group behavior recognition method based on cascade Transformer, which comprises the following steps: firstly, acquiring and generating a video data set, extracting three-dimensional spatial-temporal features from the video data set through a three-dimensional backbone network, and selecting a key frame image spatial feature map; preprocessing the key frame image spatial feature map, sending the preprocessed key frame image spatial feature map into a human body target detection Transformer, and outputting a human body target box in the key frame image; then, mapping a sub-feature map corresponding to the screened human body target box on the key frame image feature map, calculating query / key / value in combination with a key frame image surrounding frame feature map, inputting the query / key / value into a group behavior recognition Transfomer, and outputting a group level spatial-temporal coding feature map; and finally, classifying group behaviors through a multi-layer perceptron. The method has the effect of effectively improving the group behavior recognition accuracy.

The invention relates to a basic unit. A unit structure is characterized in that the basic units are periodically arranged to form an information metasurface, a switching diode in each basic unit can be controlled by an external circuit, and then different electromagnetic responses are presented; the electromagnetic response states of the basic units can be arranged and distributed in a spatial dimension according to a spatial coding sequence, and further can be periodically circulated in a time dimension according to a time coding sequence; by designing a corresponding space-time coding matrix, the information metasurface can simultaneously regulate and control electromagnetic waves in a space domain and a frequency domain; and through carrying out signal analysis on the regulated electromagnetic waves, an arrival angle of the incident electromagnetic waves can be estimated, an arrival angle estimation and electromagnetic regulation integrated method based on the information metasurface is formed, and an incident angle of the electromagnetic waves irradiating the information metasurface can be independently regulated while the incident angle is quickly estimated in real time.

The invention discloses a video prediction method based on time sequence correction convolution. The method comprises the following steps: sampling and preprocessing a given original video to obtain a video frame sequence, inputting the sequence into a time sequence context fusion module to obtain a fused appearance feature map and a fused space-time coding feature map, and inputting the sequence into a time sequence convolution correction module to obtain a convolution correction tensor; then, generating a prediction space-time coding feature map from the obtained fusion appearance feature map, the fusion space-time coding feature map and the convolution correction tensor through an adaptive convolution space-time encoder; and finally, decoding the predicted space-time coding feature map through a space-time memory decoder, and outputting a predicted video frame sequence. The method not only can correct the convolution kernel parameters according to the video frames at different moments, but also can model the internal relation of the space-time coding characteristics of the current video frame and the historical frame through the time sequence context fusion strategy, thereby generating a predicted video frame sequence with higher visual quality.

The invention discloses a digital programmable space-time coding meta-material comprising a time varying artificial electromagnetic surface and a digital control module; the artificial electromagneticsurface is formed by periodically arranging time varying encoding units in space, wherein each unit structure is integrated with a switching diode; the digital control module provides different biasvoltages so as to present different electromagnetic responses; the basic units can be controllable in space layout, and can periodically cycle in the time dimension according to a corresponding time encoding sequence, thus forming corresponding harmonic wave energy distribution in the frequency domain, finally regulating electromagnetic waves in space domain and frequency domain. The time-space encoding matrix is designed; the space-time coding meta-material can realize many fancy functions, such as harmonic wave beam scanning and scattering energy inhibition. In addition, the time dimension of the encoding meta-material can be explored, thus accurately controlling the meta-material frequency spectrum energy, and providing very important application prospects in the wireless communicationfields.

The invention discloses a fight recognition method and device based on a dual-channel cross-attention mechanism. The method first collects and generates video data sets, sets two frame rates of fast and slow to obtain different frame image sequences, and sends them to the fast and slow channels respectively after preprocessing. The fast and slow channel adopts the Transformer encoder based on the separate spatiotemporal self-attention mechanism to extract the spatiotemporal encoding features of the image sequence; then, through the cross-attention module, the CLS token of one channel and the patch token information of the other channel are fused to realize the fusion of dual-channel spatiotemporal encoding features; finally , the fused spatio-temporal coding features are passed through the multi-layer perception machine head for fighting behavior recognition. The invention can effectively extract the spatio-temporal features of the video through the dual-channel Transformer model and the cross-attention module, improve the accuracy of fighting behavior recognition, and is suitable for indoor and outdoor monitoring systems.

The invention discloses a single scan space-time coding imaging reconstruction method based on the residual network, which relates to a magnetic resonance imaging reconstruction technique based on a deep learning network. The invention provides a single scan space-time coding imaging reconstruction method based on a residual network for obtaining a two-dimensional image in a single scan and reconstructing by a deep learning method. The excitation pulse is replaced by a linear sweep pulse, which effectively resists image distortion caused by the nonuniform magnetic field and chemical shift, andat the same time obtains imaging speed, resolution and signal-to-noise ratio similar to EPI. The SPEN imaging is undersampled along the phase encoding direction. Although the space-time coding imaging signal itself can reflect the contour of the imaged object without reconstruction, the inherent resolution of the contour is typically very low. The single scan space-time coding imaging reconstruction method based on residual network utilizes deep learning to reconstruct SPEN images from low-resolution signal space, greatly improves image resolution, exhibits proton density distribution, and obtains high signal-to-noise ratio while obtaining a resolution similar to conventional deconvolution reconstruction methods.

The invention provides a water-fat separation and rebuilding method based on single-scanning space-time coding magnetic resonance imaging, and relates to a magnetic resonance imaging method. The method comprises the steps of utilizing a single-scanning space-time coding and imaging sequence to encode and collect a water-fat signal, wherein a 90-degree linear frequency sweep pulse is combined with a space-time coding gradient to give one quadratic phase to the water-fat signal in an exciting stage; based on the characteristic, obtaining priori knowledge images of water and fat used for guiding water-fat separation and rebuilding by selecting an appropriate filter to preprocess collected data; in a water-fat separation stage, utilizing the priori knowledge images as an initial value and weighted information, and obtaining a high-resolution and high-signal-to-noise ratio water image and fat image by solving a super-resolution lifting and edge artifact removing algorithm equation in a water-fat environment. According to the water-fat separation and rebuilding method based on single-scanning space-time coding magnetic resonance imaging, the water-fat separation of single-scanning space-time coding magnetic resonance imaging can be effectively achieved, meanwhile the image quality of separated images is improved, and the clinical application progress is promoted.

A disclosed transmitter for wireless communication includes multiple transmitting antennas, a symbol mapper for mapping an input block including multiple binary bits and representing information to be transmitted to a symbol representing an ordered plurality of complex numbers, a space-time encoder for applying an encoding operator to the symbol to produce a vectorized space-time codeword defining electrical signals to be transmitted by the transmitter, the encoding operator being dependent on a set of predefined stabilizer generators, and circuitry to collectively transmit, by the antennas to multiple receiving antennas of a receiver over a wireless transmission channel, the electrical signals defined by the vectorized space-time codeword. The receiver includes a space-time decoder for recovering the symbol from the electrical signals transmitted by the transmitter using a decoding operation that is based on maximum likelihood inference, and a symbol de-mapper for recovering the input block from the symbol.

The invention discloses a device and method for authenticating block chain data using spatio-temporal information. The device includes a spatio-temporal block chain terminal, a spatio-temporal encoding module, a block chain module and a server; The data generated within a certain period of time can be uploaded to the blockchain system only if it is correct and valid; it eliminates the possibility of counterfeit terminals transmitting data to the blockchain system; The possibility of data transmission in the block chain system, so as to ensure that the source of the data transmitted to the block chain is reliable; the time of the device is guaranteed to be difficult to tamper; the smart contract of the block chain is adopted, which has the characteristics of not being tampered with, and realizes distributed Storage ensures that even if some server node data is lost or damaged, the system can still operate normally.

The invention discloses a broadband zero cross polarization space-time coding digital metasurface unit and a control method. A radiator is used. The edge of the radiator is provided with a plurality of micro-tuning sheets and a micro-tuning hole in the center. The radiator is connected with the radio frequency switch. The two states of turning off and turning on the radio frequency switch are respectively corresponding to a turning-off mode and a turning-on mode. By optimizing the sizes of the micro-tuning holes and the micro-tuning pieces, the electric field distribution of the turn-off modeand the electric field distribution of the turn-on mode are kept consistent near the target frequency as much as possible, so that the stable phase difference between the two modes is obtained, and the space-time coding digital metasurface unit can work in the regulation and control of the broadband one-bit 180-degree reflection phase. Besides, through reasonable design of the AC-DC isolator, loading of the bias circuit hardly changes the original phase difference of the unit, unit loss is avoided, and unnecessary cross polarization caused by damage to the symmetry of the unit is avoided. According to the invention, 180-degree phase shift is realized within the frequency band of 7.71-9.48 GHz.

The radio transmission device of the present invention is provided with: a plurality of transmission antennas; The initial symbol generating part (2), as the reference signal when differential encoding starts, generates the initial symbol; The differential encoding unit (differential encoding section 3, transmission signal power Calculation section 6, one-square-root calculation section 7), carry out differential encoding to the transmitted symbol mapped with information bit to generate the symbol after differentiation; Perform space-time encoding to generate signals transmitted from each transmitting antenna, and the differential encoding unit determines the differential encoding generated in this differential encoding process based on the power of the initial symbol or the power of the differentially differentiated symbol generated last time. The power of the following symbol.

Described here are systems and methods for volumetric excitation in magnetic resonance imaging (“MRI”) using frequency modulated radio frequency (“RF”) pulses. In general, quadratic phase modulation along the slice encoding direction is implemented for additional spatiotemporal encoding, which better distributes signal content in the slice direction and enables higher acceleration rates that are robust to slice-undersampling.

The invention discloses a transceiving method and a realization device thereof used for single frequency network signals in the technical field of digital television networks, which comprise the steps as follows: a PN frame header after PN frame header time coding processing and transmitting signal combined processing is inserted in front of a data section at a transmitting end; moreover, relevant PN processing and channel estimation processing are implemented at a receiving end. Aiming at solving a problem that received signals can not be effectively resolved due to multipath interferences caused by the single frequency network in overlapping areas, coding processing is implemented on the PN frame header before modulation, and then data jointing and demodulating transmitting are implemented; during receiving, a transmitting signal is obtained through relevant processing and channel estimation on the received and coded PN frame header as well as known PN frame header. The invention greatly improves the signal-to-noise of the channels, and can obtain an effective signal from the interfered signals more easily.

The invention discloses a video prediction method based on a time-space propagation hierarchical codec. The method of the present invention first samples the given original video to obtain the frame sequence and inputs it to the low-level visual memory encoder to obtain the low-level visual coding features and low-level memory state features; features, and extract high-level semantic features through a high-level semantic encoder; then fuse the obtained low-level visual coding features, low-level memory state features, and high-level semantic coding features through a hierarchical feature decoder to output predicted video frames. The method of the present invention can not only integrate the low-level visual memory features and high-level semantic features, but also make the low-level visual information spread along the time sequence direction through the spatio-temporal propagation module, and can also use the prior knowledge of the first frame of the video to solve the video frame blur problem to a certain extent, Improve overall clarity and visual quality of predicted video frames.

The invention discloses a programmable non-reciprocal transmission and frequency conversion system based on a space-time coding metasurface. The programmable non-reciprocal transmission and frequencyconversion system consists of the space-time coding metasurface and a digital control circuit, wherein the metasurface is formed by periodically arranging time-varying programmable units in space; each unit integrates a plurality of adjustable devices; and multi-bit phase period modulation is presented under the driving of the digital control circuit. According to a specifically designed time andspace phase gradient, efficient frequency conversion and abnormal reflection of incident electromagnetic waves are realized, so that time reversal symmetry is broken through, and a non-reciprocal effect is realized in a space domain and a frequency domain. In addition, different space-time coding matrixes are output through the digital control circuit; the system can be switched between reciprocaland non-reciprocal transmission; a non-reciprocal reflection angle and a harmonic frequency can be adjusted in real time; the dynamic programmable system is realized; and the system has potential applications to the fields of space frequency conversion, Doppler deception, directional transmission, radio frequency stealth, secret communication, isolators, duplexers, frequency mixers and the like.

The invention discloses a segmented excitation based multi-echo multi-layer space-time coding magnetic resonance imaging method, and relates to a magnetic resonance imaging method. The method comprises the following steps: dividing an imaging object into several segments; selecting an imaging segment through a 90-degree segment selection pulse; performing time-space coding of intra-segment core spinning through a 180-degree linear frequency sweep pulse; enabling the core of non-imaging segment to spin to a heat balance state by using a 180-degree hard pulse; storing the spinning information byusing the same pulse as the 90-degree segment selection pulse; sequentially exciting multiple target layers by using multiple 90-degree layer selection pulses; in combination with the specific dispersed phase gradient of frequency coding dimension, enabling the signals on different layers to form echoes at different sampling moments; changing the center frequency of the layer selection pulse andrelevant pulse gradient, to obtain magnetic resonance data on each layer in the segment; modifying the center frequency of the segment selection pulse, and selecting different imaging segments; repeating the above operations to obtain data of the whole imaging object; dividing the data of multiple echoes acquired at the same time, according to the echo number; and performing super-resolution reconstruction of the data on each layer, to obtain a multi-layer high-resolution magnetic resonance image.

One or more embodiments of this specification disclose a space-time coding method, a space-time index and query method and device, which are used to realize efficient organization, management and query of massive multi-source remote sensing data. The method includes: subdividing the longitude-latitude space of the earth according to a specified subdivision method to obtain multiple grids; wherein, the numbers of grids corresponding to the longitude direction and the latitude direction are the same; Hierarchical; Integer encoding is performed on the coordinate information corresponding to each of the grids to obtain first coded values ​​corresponding to each of the grids; establishing the grids and the first encoding values ​​corresponding to each of the grids An association relationship between the encoded value and the remote sensing image data. The technical solution can use the global multi-scale grid integer coding to realize the location association with the multi-source remote sensing data, and realize the space-time index and query of the multi-source remote sensing data.

The present invention relates to the field of computer vision and deep learning, and in particular to a video group behavior recognition method based on cascaded Transformers. First, a video data set is collected and generated, and the video data set is extracted through a three-dimensional backbone network to extract three-dimensional spatio-temporal features, and a key frame image space is selected. Feature map; preprocess the key frame image space feature map and send it to the human target detection Transformer to output the human target frame in the key frame image; then, map the sub The feature map is combined with the frame feature map around the key frame image to calculate the query / key / value, input the group behavior recognition Transformer, and output the group-level spatio-temporal encoding feature map; finally, the group behavior is classified by the multi-layer perceptron. The invention has the effect of effectively improving the accuracy of group behavior recognition.

The invention relates to an image distortion correction method based on single-scan hybrid spatio-temporal coding magnetic resonance imaging, which is characterized in that it includes: step 1, firstly positioning the region of interest of the imaging object; step 2, importing pre-compiled A good single-scan mixed space-time coding sequence; step 3, data sampling; step 4, determine the effective peak center position of each sampled echo; step 5, calculate the peak center position of each echo in the uneven field relative to the ideal situation The number of deviation points of the center position of the lower echo; step 6, calculate the reading gradient offset area caused by the deviation of each echo peak position under the uneven field; step 7, calculate the effective echo time of each echo signal; step 8 , Calculating the equivalent inhomogeneous field magnetic susceptibility gradient value G inh ; Step 9, using the equivalent inhomogeneous field gradient value calculated in step 8 to correct the distorted image. The invention has the robustness to the non-uniform field in the traditional phase encoding direction.