106results about How to "Easy to implement in real time" patented technology

The invention relates to an interference pattern recognition technology of a frequency hopping system, belonging to the field of broadband wireless communication. The technology is mainly used for analyzing various interference types of the frequency hopping system. On the premise of not increasing frequency hopping bandwidth and frequency hopping speed, the recognition for various interference patterns can be realized. First, pretreatment for removing frequency hopping points is carried out on the received signals; then, characteristic parameters such as time domain, frequency domain, time-frequency domain and the like of interference signals can be extracted for mode recognition, so that classified recognition of the different interference types can be realized. The technology has better recognition effect for the various common interference types as well as stronger robustness and stability, and provides reliable basis for further interference suppression. In addition, the method has low computational complexity and is easy to realize in real time by the system.

The invention relates to a method for inhibiting MPSK narrowband interference of a direct sequence spread spectrum system (DSSS), and belongs to the technical field of anti-interference of communication. In the method, a main lobe and a side lobe of a MPSK narrowband interference signal are inhibited respectively by adopting a method of combining a frequency domain and a time domain. The method comprises the following steps of: by adopting a method of segmentation overlay processing, inhibiting the main lobe of the MPSK narrowband interference signal as many as possible, and simultaneously ensuring that the energy loss of the useful signal is reduced as much as possible by using the difference between the noise characteristics of the DSSS communication signal in the frequency domain and the energy focusing characteristics of the MPSK narrowband interference signal; and inhibiting the side lobe of the MPSK narrowband interference signal in the time domain so as to effectively separate the interference signal from the useful signal, achieve high performance of bit error rate and guarantee reliable communication of the DSSS by using the characteristics that the frequency spectrum of the side lobe of the MPSK narrowband shows an impulse form. In addition, the method has low computational complexity and is easily implemented by the system in real time.

The invention belongs to the technical field of radar moving target detection, and particularly relates to a space-time adaptive processing method for airborne forward-looking array radar. The method includes the specific steps of obtaining a data vector xnk1, received by the kth pulse of the nth line of array elements of a receiving array of the airborne forward-looking array radar, of a first distance door, obtaining the data vectors, recorded by the nth line of array elements of the receiving array of the airborne forward-looking array radar, of selected distance doors recorded within the time period of [KT, (K+1)T], obtaining the estimation (please see the specifications) of the dimensionality reduction pitching covariance matrix of the first distance door of the nth line of array elements of the receiving array of the airborne forward-looking array radar, obtaining the dimensionality reduction self-adaption weight vector omega E of the first distance door of the nth line of array elements of the receiving array of the airborne forward-looking array radar, obtaining the data vector ynk1, received by the kth pulse of the nth line of array elements of the receiving array of the airborne forward-looking array radar, of the first distance door after pitching pre-filtering is conducted, and obtaining the signal of the kth Doppler channel of the first distance door of the airborne forward-looking array radar through the orientation-Doppler space-time adaptive processing method after the space-time adaptive processing is conducted.

The invention relates to a textural feature-based no-reference image quality evaluation method. The method comprises the following specific steps of: dividing a graphic database into a training image set and a test image set; constructing images uder different scales for each image; solving normalized brightness images for the images under different scales; solving normalized gray-level co-occurrence matrixes in four directions for the normalized brightness images; calculating energy, entropies, contrast ratios and dependencies of the normalized gray-level co-occurrence matrixes to combine a feature vector; sending the feature vector and a subjective MOS score to a support vector machine to carry out training; and predicting test images by using the trained support vector machine so as to obtain an objective image quality evaluation result. According to the method, image quality evaluation is carried out by utilizing textural features; compared with the existing algorithms, the method is lower in calculation complexity and convenient to realize in real time, and has the effect of improving the prediction precision through extracting the textural features by utilizing the gray-level co-occurrence matrixes with a plurality of scales and a plurality of angles.

The invention belongs to the technical field of radar echo simulation, and particularly relates to a radar echo real-time simulation method based on an FPGA and a DSP. The method comprises the following steps that 1, the following data of the position coordinate of a radar at each direction moment, the coordinate and grey value of each pixel point in a rectangular face object scene and the conjugate item of a distance direction matching function are prestored in an FPGA chip, and according to the data prestored in the FPGA chip, the distance unit serial number corresponding to each pixel point in the rectangular face object scene at each direction moment and direction echo data are obtained; 2, the FPGA chip transmits the two parts of data calculated and obtained in the step 1 to a DSP chip, the DSP chip carries out data integration on the data from the FPGA chip, and a matrix H is obtained; 3, the DSP chip transmits the matrix H to the FPGA chip, and a radar echo data matrix is obtained by the FPGA chip according to each line of elements of the matrix H and the conjugate item of the distance direction matching function.

The invention discloses a nonlinear control method of a Buck-Boost converter system. The nonlinear control method of the Buck-Boost converter system is characterized by comprising the following steps that first, an input voltage, an inductive current, a capacitor voltage and a state average model of a Buck-Boost converter main circuit are obtained; then, the cooperative control law of the Buck-Boost converter system is obtained; afterwards, the expectation value of the inductive current is obtained; at last, the cooperative passive control law of the Buck-Boost converter system is obtained, and therefore nonlinear control over the Buck-Boost converter system is achieved. By means of the nonlinear control method of the Buck-Boost converter system, the transient overshoot of the inductive current of the Buck-Boost converter system can be effectively removed, the steady state error of the capacitor voltage is reduced, and thus the stability of the Buck-Boost converter system is improved.

The invention provides a method for compensating and enhancing a dynamic shielded image in real time, solves the real-time compensation and enhancement problems of the dynamic shielded image and improves the quality of the dynamic shielded image. The technical proposal comprises the steps of estimating the motion vector between two adjacent images by a moderate method based on a video image output by a camera, combining motion compensation with a time domain Kalman filter technique of a pixel gray value, performing time domain filtering treatment for all pixels so as to compensate the image information of a dynamic shielded area, and finally performing self-adaptive grey widening and edge enhancement treatments for the compensated image.

The invention discloses an infrared image sea-sky-line self adaption detection method which includes the following steps that (1) an original infrared image Forg is obtained; (2) edge detection is conducted on the original infrared image through a Canny operator, and an edge image Fedge is obtained; (3) a sliding window model MWin, the sea-sky-line length and a model LEN sum <j> are built; (4) full-figure traversal is conducted on the edge image Fedge through the sliding window model MWin, and the sum of lengths of sea-sky-lines of different lines is solved; (5) the length of the sea-sky-lines and the line with the maximum LEN sum are defined to be the positions of the current image sea-sky-lines; (6) smoothing is conducted on the current image sea-sky-lines, and the filter value Lineseasky <p+1> of the p+1th frame of the sea-sky-lines is output.

The invention discloses an infrared image detail enhancement and noise adaptive inhibition method. The method comprises the following steps of (1) acquiring an original infrared image Forg; (2) utilizing a differential operator to calculate a filter component Fd of the original infrared image; (3) calculating the background complexity of the original infrared image, and determining a noise inhibition threshold value T1; (4) calculating a region variance V of the original infrared image, performing binaryzation on a region variance image according to an initial threshold value T2, and utilizing a matrix BW to express the binarized image; (5) calculating a weighting matrix Coe of the filter component Fd; and (6) outputting a detail enhancement image Fout. Compared with the prior art, the infrared image detail enhancement and noise adaptive inhibition method has the following advantages that (1) the infrared image detail enhancement and noise adaptive inhibition method is particularly used for processing a signal-to-noise ratio image, and can effective inhibit the noise amplification of the image while the image detail is enhanced.

The invention discloses a weighting LMS detection method for harmonic currents. The method comprises aspects that (1) cost functions are defined to be weighted square sums of posteriori errors, so that interference of harmonic currents on filter weight coefficients is eliminated; (2) updating increments of the filter weight coefficients are achieved through iteration, so that the calculation complexity is reduced; (3) conditions for guaranteeing stability are given. Compared with an LMS algorithm and a recursive least square (RLS) algorithm, the weighting LMS detection method has the advantages of being small in steady-state error and high in jump occasion tracking capacity to load currents. The calculation amount of the method is slightly larger than that of the LMS algorithm but smaller than that of the RLS algorithm, so that the method is applicable to detection of harmonic currents.

The present invention discloses a real-time recovery method of moving-target in high frame frequency infrared image sequence. The method includes steps as follows: inputting high frame frequency infrared image frame, confirming sporting direction and distance parameter of moving-target in image frame, processing median filtering in sporting direction, confirming membership degree of seed pixel and neighborhood pixel according with given membership degree function, confirming pixel value of seed pixel according with judgement criterion, outputting image frame recoveried by moving. The method reduces noise effect by median filtering to input image sequence; has no strict request for size and moving speed of target, and has efficient in working; the median filtering, convolution operation and confirming membership degree operation of seed pixel and neighborhood pixel are processed in air space, and not need global properties of noise which makes arithmetic simply, no ringing effect and hardware realized real-time.

The invention discloses a real-time tracking method for an infrared image target with multi-feature fusion. The real-time tracking method comprises the following steps of: initializing a target tracking point position; initializing a target model; calculating a target candidate model; calculating a coefficient of unified feature Bhattacharyya and weight coefficients between feature; calculating a new tracking position of a current frame target; estimating the coefficient of the unified feature Bhattacharyya at the new position; and comparing the two coefficients of the unified feature Bhattacharyya and outputting results. The real-time tracking method can be used for adaptively calculating the weight coefficients between multiple features, enhances the robustness of target tracking, ensures the stability of target tracking, solves the problem of tracking point drifting caused by unstable single feature, and effectively improves the accuracy of target tracking.

The invention provides a secondary radar answer code extracting and confidence interval marking algorithm, synthetically using position of answer pulse, sigma and Delta information and adjacent answer information, adopting an idea of establishing a pulse information list for each answer pulse, convenient to implement software programming. It has the characters of high processing efficiency, strong self-adapting ability, convenience for real-time implementation, etc. It can be used in processing answer signals for secondary radar, enemy-self identifier, and civil aviation management system.

The invention relates to the field of access control in a wireless communication technology, in particular to an opportunistic channel accessing and switching method and device. The method comprises the following steps of: receiving, by a receiving end, an RTS (Request To Send) data packet comprising a training sequence transmitted by a transmitting end through a detected idle channel; acquiring a channel state of the idle channel according to the training sequence; judging whether the channel state is greater than or equal to optimal threshold k*; and if the channel state is greater than or equal to the optimal threshold k*, accessing to the idle channel to perform transmission of a data stream, and otherwise, switching the channel by the transmitting end and the receiving end according to a shared channel detection sequence, and searching and detecting a next idle channel. According to the method and the device, a user can obtain the channel state according to the training sequence, adjust the accessing and the switching of the channel and maximally utilize the instantaneous transmission opportunity of the channel in time-frequency two dimension, so that the utilization efficiency of the channel is improved; diversity utilization is performed on a link layer; and compared with the conventional physical layer diversity technology, extra accessory hardware is not required, and the conventional communication equipment is favorably applied.

The invention provides a selective cognitive access method on the basis of the quality of channels. The selective cognitive access method includes steps of acquiring the optimal threshold of a cognitive radio system; enabling a cognitive terminal to sequentially perceive and detect the various channels when the cognitive terminal needs to transmit data, and judging whether the real-time state of a detected channel Ci meets conditions or not; enabling the cognitive terminal to access the channel Ci if the real-time state of the channel Ci meets the conditions; sequentially transmitting the data via the channel Ci; enabling the cognitive terminal to monitor the real-time state of the channel Ci; enabling the cognitive terminal to instantly release the current channel Ci if the cognitive terminal detects that the real-time state of the channel Ci is lower than or equal to the optimal threshold; and perceiving and detecting the channels again. The conditions include that the channel Ci is an idle channel, and the link quality of the channel Ci is superior to the optimal threshold. The selective cognitive access method has the advantages that a channel access and release decision is made for the cognitive terminal under joint consideration of the availability and the instantaneous link quality of the channels, and the frequency spectrum utilization efficiency can be greatly improved.

The invention discloses a space intersection control method of two-stage constant thrust, which is used for solving the technical problem that the engine is opened and closed frequently during the intersection process when the prior intersection control method of constant thrust is achieved. The technical solution is that the minimum opening-closing time Tmin constraint of the engine is introduced to the intersection control problem of the two-stage constant thrust engine; and the optimal intersection thrust under quadratic optimization function index is designed by rolling forecast principle. Because of considering the minimum opening-closing time constraint of the engine, the problem that the engine is opened and closed frequently is solved and the design difficulty of the engine is reduced; and the optimal design method has good robustness for design model error, measurement error and intersection thrust error.