513 results about "Point method" patented technology

Methods for compensating for phase shifts of a communication signal. The methods involve determining a first reference signal (Vref-1) at a first location along a transmission path and a second reference signal (Vref-2) at a second location along the transmission path. Vref-2 is the same as Vref-1. At the first location, a first phase offset is determined using Vref-1 and a first communication signal. At the second location, a second phase offset is determined using Vref-2 and a second communication signal. A phase of a third communication signal is adjusted at the second location using the first and second phase offsets to obtain a modified communication signal. The first, second, and third communication signals are the same communication signal obtained at different locations along the transmission path.

Methods and systems for classifying WLAN access points according to the quality of estimation of characteristics of the WLAN access points are provided. The classifications may be used to scale a reference database and quantify an expected error of estimation of the characteristics of the access points. WLAN access points may be classified based on their impact on a user's position, speed of travel, and direction of travel estimation accuracy in a WLAN positioning system. A method for determining a quality of estimation of characteristics of a Wi-Fi access point comprises a Wi-Fi enabled scanning device measuring a number of received signal strength (RSS) samples of the Wi-Fi signal transmitted by the Wi-Fi access point. A total distance traveled by the Wi-Fi enabled scanning device while measuring the number of RSS samples is estimated and used to estimate the quality of estimation of characteristics of the Wi-Fi access point.

Methods and systems for multi-access point transmission of data using a plurality of access points are disclosed. Methods include identifying a plurality of access points to be used cooperatively in combination with each other for the transmission of data to a receiver. The transmission of the data to the receiver via the plurality of access points is enabled utilizing at least one multi-access point transmission scheme.

The invention discloses a depth camera-based visual mileometer design method. The method comprises the following steps of acquiring the color image information and the depth image information in the environment by a depth camera; extracting feature points in an initial key frame and in all the rest image frames; tracking the position of each feature point in the current frame based on the optical flow method so as to find out feature point pairs; according to the number of actual feature points and the region size of the overlapped regions of feature points in two successive frames, selectively adopting the sparse direct method or the feature point method to figure out relative positions and postures between two frames; based on the depth information of a depth image, figuring out the 3D point coordinates of the feature points of the key frame in a world coordinate system based on the combination of relative positions and postures between two frames; conducting the point cloud splicing on the key frame during another process, and constructing a map. The method combines the sparse direct method and the feature point method, so that the real-time performance and the robustness of the visual mileometer are improved.

Methods, systems, computer-readable media, and apparatuses for determining locations of access points (AP) are presented. Techniques are described for determining relative and absolute locations of APs. In one embodiment, a device may send and receive messages to one or more APs for from various locations for determining the distance between the device and the AP. The device may additionally keep track of its own displacement for the purposes of determining the location of the one or more APs. In one embodiment, the device also determines the turnaround calibration factor (TCF) for the AP that compensates for the processing time at the AP may also be used for increasing the accuracy of the determination of the location of the AP.

The invention discloses a simultaneous localization and mapping (SLAM) method for an unmanned aerial vehicle based on mixed vision odometers and a multi-scale map, and belongs to the technical field of autonomous navigation of unmanned aerial vehicles. According to the SLAM method, an overlooking monocular camera, a foresight binocular camera and an airborne computer are carried on an unmanned aerial vehicle platform; the monocular camera is used for the visual odometer based on a direct method, and binocular camera is used for the visual odometer based on feature point method; the mixed visual odometers conduct information fusion on output of the two visual odometers to construct the local map for positioning, and the real-time posture of the unmanned aerial vehicle is obtained; then theposture is fed back to a flight control system to control the position of the unmanned aerial vehicle; and the airborne computer transmits the real-time posture and collected images to a ground station, the ground station plans the flight path in real time according to the constructed global map and sends waypoint information to the unmanned aerial vehicle, and thus autonomous flight of the unmanned aerial vehicle is achieved. Real-time posture estimation and environmental perception of the unmanned aerial vehicle under the non-GPS environment are achieved, and the intelligent level of the unmanned aerial vehicle is greatly increased.

The invention discloses a fast monocular vision odometer navigation and positioning method fusing a feature point method and a direct method, which comprises the following steps: S1, starting the vision odometer and obtaining a first frame image I1, converting the image I1 into a gray scale image, extracting ORB feature points, and constructing an initialization key frame; 2, judging whether thatinitialization has been carry out; If it has been initialized, it goes to step S6, otherwise, it goes to step S3; 3, defining a reference frame and a current frame, extracting ORB feature and matchingfeatures; 4, simultaneously calculating a homography matrix H and a base matrix F by a parallel thread, calculating a judgment model score RH, if RH is great than a threshold value, selecting a homography matrix H, otherwise selecting a base matrix F, and estimating a camera motion according to that selected model; 5, obtaining that pose of the camera and the initial 3D point; 6, judging whetherthat feature point have been extracted, if the feature points have not been extracted, the direct method is used for tracking, otherwise, the feature point method is used for tracking; S7, completingthe initial camera pose estimation. The invention can more precisely carry out navigation and positioning.

Methods and a vehicle are provided for initiating a short range radio frequency (RF) connection between the vehicle and an access point. The vehicle includes transceiver circuitry comprising receiver circuitry and transmitter circuitry, a Global Positioning System (GPS) receiver for receiving GPS coordinates, and a controller. The controller is coupled to the GPS receiver for determining a location of the vehicle in response to the GPS coordinates. The controller is also coupled to the transmitter circuitry for providing a probe request thereto for transmission to the access point in order to initiate the short range RF connection in response to the location of the vehicle.

A target selection object is selected by providing N (N is an integer of not less than two) keys used for pointing, dividing a screen into N areas in correspondence with the N keys and displaying the N areas such that they can be distinguished, enlarging, when the key corresponding to the area where the target selection object exists is operated by a user, only the area corresponding to the key to the size of one screen and displaying the screen obtained by the enlargement, and dividing the screen into N areas in correspondence with an arrangement of the N keys and displaying the N areas such that they can be distinguished, and performing the same processing every time a key operation is performed by the user.

The invention provides a system for detecting mass, mass center and mass offcenter of a cylinder, and belongs to the measurement technical field. The system for detecting the mass, the mass center and the mass offcenter of the cylinder comprises a main controller, a data acquisition module, a control interface module, a signal conditioning circuit, a motor driving circuit, a distance measuring device, a power module, a lifting motor, four weighting sensors and a lifting platform. The cylinder to be measured is clamped on a tray at one time, the lifting motor is started, the tray is landed on the weighting sensors, the distance measuring device is moved to measure a reference distance of the cylinder, and then data of the sensors are acquired twice in a front and back mode when the cylinder rotates by 90 degrees, and a detecting result of the mass, the mass center and the mass eccentricity of the cylinder can be acquired according to a four-point method. The system for detecting the mass, the mass center and the mass offcenter of the cylinder has the advantages of being compact in structure, large in measuring diameter range, high in measuring accuracy and automation degree, and capable of being used in delivery detection, factory acceptance inspection and quality characteristic detection of cylinder parts or products.

The inventors provide herein methods for the decomposition of initial Filter Criteria (iFCs) into user-independent, global data and user specific data. In various embodiments of the present invention, the approach is based on Trigger point templates that represent families of trigger points, which are able to be instantiated to real trigger points by adding missing user specific data. Trigger point templates are specified at service deployment time and are instantiated to real trigger points and complemented with the other iFC components to form complete iFCs at the time of service subscription. It is demonstrated that the trigger point methods of the present invention facilitate the storing, provisioning and downloading of initial filter criteria and are beneficial in terms of at least storage and run-time efficiency.

The invention discloses an flame retardant non-woven cotton fabric, comprising anti-fcell flame retardant fiber and washing / washing composite hot melting short fiber, wherein, the weight percentage of the anti-fcell flame retardant fiber is between 70 and 90 percent, the balance is the washing / washing composite hot melting short fiber; the two fibers are stuck into an integrated whole by the hot wind heating and / or are penetrated together by prickling fibers to combine into the non-woven fabric. The method for producing the non-woven cotton fabric comprises the processes of mixing, opening, carding, mesh placing, moulding processing, etc. The moulding processing method has the needle point method and the through-air method. The flame retardant non-woven cotton fabric adopts the prescription of mainly taking the anti-fcell flame retardant fiber and solves the problems of the flammability of the terylene, dropping of the fusion and the flammability of the viscose. The washing / washing composite hot melting short fiber is added to increase the caking coefficient so that the fibers are conglutinated evenly. The unique processing flow ensures that the inflaming retarding non-woven cotton fabric has high tension intensity and anti-breakage intensity as well as certain elasticity and bulkiness.

The invention discloses a method for detecting radial motion error of a high-speed principal axis by adopting a multi-circle superposition three-point method. Three laser displacement sensors are distributed around the high-speed principal axis which is provided with an angle encoder that has N lines and is connected with a scaling circuit; when the scaling circuit counts for Z times in an accumulating way and Z can not be divided exactly by N, the scaling circuit outputs sampled signals, and a trigger sensor implements sampling once; by repeating in this way, the principal axis is evenly distributed with n points for sampling by rotating the principal axis for a plurality of times to complete a sampling period; after every time of sampling, the sampling value is transmitted to an industrial computer through a USB interface and is then recorded; according to the requirements of detection accuracy, the sampling work having a plurality of sampling periods is carried out, the average sampling value of n points of every laser displacement sensor is calculated, and the deviation from circular form, the eccentric error and radial turning error of the principal axis which are obtained by separation are calculated. The method is not sensitive to the performance of the laser displacement sensor and is suitable for detecting radial motion error of the high-speed principal axis.

Disclosed in the utility model is a virtual viewpoint rendering method. The method comprises the following steps: obtaining a set of left and right viewpoint images shot by a camera and carrying out SIFT feature extraction on the set of viewpoint images to generate feature points and a feature vectors; carrying out Euclidean distance-based feature matching on the feature points of the left and right viewpoint images by the feature vectors to obtain a matching point pair set; calculating a basis matrix for the matching point pair set by using a random sample consensus method and an eight-point method; using homography decomposition to calculate homography matrixes of the left and right viewpoint images based on the basis matrix and using the corresponding homography matrixes to correct the left and right viewpoint images; carrying out stereo matching on the corrected left and right viewpoint images and generating an intermediate viewpoint image by interpolation and synthetizing; carrying out postposition conversion on the synthetized intermediate viewpoint image to obtain a virtual viewpoint image; and carrying out hole filling on the virtual viewpoint image and outputting a final virtual viewpoint image. According to the invention, the real-time performance is improved; the application range is expanded; and software has been made based on the method and is applied to experiment and application.

A satellite navigation automatic driving system of a high-speed seedling transplanter is composed of an RTK-GPS, an attitude instrument, odometers, a rotation angle sensor, an electronic control steering wheel, a GPS data forwarding electronic control unit (ECU), an attitude instrument data forwarding electronic control unit (ECU), an odometer electronic control unit (ECU), a steering wheel electronic control unit (ECU), an embedded navigation computer EGC and the like. A traditional manual steering wheel is replaced by the electronic control steering wheel; the RTK-GPS and the attitude instrument are arranged at the center of a cross-over support on a seedling disc support; the odometers are arranged on walking reducers of left and right wheels; the rotation angle sensor is arranged at a steering mechanism of the bottom of a main reducer; each electronic control unit (ECU) is arranged near the sensor; the EGC is mounted at one side of the seedling disc support; the EGC is connected with the ECUs through a serial communication network; the EGC includes a man-machine interface as well as pre-data processing, attitude estimation and driving control modules; in seedling transplanting, a target point method is adopted to realize tracking automatic driving; and in corner turning, a method in which attitudes are adjusted around a corner turning center is adopted to realize automatic driving. With the satellite navigation automatic driving system adopted, the seedling transplanter can be driven by a computer, and therefore, onboard operation personnel can be reduced to only one seedling supplementing worker.

Method, system and computer program for efficiently extracting and describing scale-space interest points. It is designed towards low overall computational complexity. On one hand, the data acquired during extraction in the description phase is intensively re-used. On the other hand, an algorithmic optimization of the description that dramatically speeds up the process, is proposed. First, the image is filtered with triangle kernel at different scales. The triangle filtered images are reused for extraction of the keypoints dominant orientation and the computation of the DAISY-like descriptor

A placement position of a sketched image into a three-dimensional space and viewing point direction are determined using the angle method or the three-point method, and the cross-section lines of a door cross-section line and center cross-section line of a vehicle depicted in the sketched image is determined and, based on the obtained cross-section line and center cross-section line, a spatial curved surface of the vehicle in the three-dimensional space is determined, distortion is corrected, and a curved surface is created.

The invention discloses a method for estimating target rotation of an inverse synthetic aperture radar (ISAR) based on time-space image sequence, which comprises the following steps: acquiring a time-dimensional RD image sequence of the ISAR according to the received echo data; and analyzing and estimating the rotation of a target by tracking attitude change between images caused by the rotation of the target; judging whether the rotation planes of the target in any two RD images are coplanar according to a time-space two-dimensional image sequence acquired by a single receiver or a plurality of receivers; when the rotation planes are coplanar, further improving the estimation precision of a rotation parameter through a dominant point method or a rotation related method; moreover, realizing large-angle high-resolution imaging by PFA or CBP algorithm; and when the rotation planes are non-coplanar, estimating the azimuth and pitching rotation information of the target so as to realize three-dimensional imaging of the target. The method ensures the target rotation estimation precision and stability, and meanwhile can improve the performance of the ISAR imaging in the three aspects of transverse calibration, large-angle high-resolution imaging and three-dimensional imaging. Moreover, compared with the conventional target rotation estimation method, the method has high precision, and is easy in engineering realization.

The method includes following steps: obtaining online data of power network from energy management system and power market; determining probability of equipment fault in the time period based on arrangement of equipment repair and weather condition in each area; creating sample space from Monte Carlo simulation, each sample includes two parts: X (increment direction of power), and Y (set of fault equipment); calculating steady tolerance of voltage corresponding to each sample and obtaining probability density distribution of voltage of voltage in power system from layered computation method; determining value of steady tolerance system needed to reach, limiting values of system parameters, and precaution control value; adjusting working parameters of system to ensure steady voltage in power system under specified confidence level. Advantages are: getting rid of a great lot calculation in traditional 'point-by-point method' and avoiding CPF calculation again.

There is disclosed an acoustic pointing device that is capable of performing pointing manipulation without putting any auxiliary equipment on a desk. The acoustic pointing includes a microphone array that retains plural microphone elements; an A / D converter that converts analog sound pressure data into digital sound pressure data; a buffering that stores the digital sound pressure data; a direction of arrival estimation unit that executes estimation of a sound source direction of a transient sound based on a correlation of the sound between the microphone elements obtained by the digital sound pressure data; a noise estimation unit that estimates a noise level in the digital sound pressure data; an SNR estimation unit that estimates a rate of a signal component based on the noise level and the digital sound pressure data; a power calculation unit that computes and outputs an output signal from the rate of a signal component; an integration unit that integrates the sound source direction and the output signal to specify a sound source position; and a control unit that converts, based on data in a DB of screen conversion, the specified sound source position into one point on a screen of a display device.

A system and method for MR magnetic field mapping includes a computer programmed to acquire a first data point at a first location in a first phase image data set, a second data point at the first location in a second phase image data set, a third data point at the first location in a third phase image data set. The first, second, and third phase images are acquired using a first, second, and third TE, respectively. Phase wrapping does not occur among the first and second phase image data sets; however, phase wrapping does occur among the second and third phase image data sets. The computer is also programmed to determine a magnetic field inhomogeneity, wherein the determination of the magnetic field inhomogeneity is based on the first, second, and third data points.

The invention discloses a visual SLAM method based on multi-feature fusion, and relates to the field of robot visual positioning and mapping. The invention discloses a multi-feature fusion vision SLAM(simultaneous localization and mapping) method based on a depth camera, which solves the vision positioning problem under the condition that pure point features fail by fully using point-line features extracted from an image and constructing plane features according to the point-line features. A self-adaptive threshold method is adopted to extract point features, so that more uniform point features can be obtained; line features are extracted, short and small line segments are deleted, and the segmented line segments are combined to improve the accuracy of line feature matching; wherein the point-line features are used for estimating the inter-frame pose and constructing a local map; a surface feature is calculated by adopting a minimum parameter method to reduce the calculated amount; the point, line and plane features are tightly coupled by constructing a back projection error function of the fusion features, and a global map is constructed to carry out global pose optimization. Thevisual SLAM method is high in precision, good in real-time performance and high in robustness, and the problem that the visual SLAM precision is reduced or even a system fails in a low-texture environment based on a feature point method is solved.

The invention discloses an improved holographic dynamic balancing method of a high-speed main shaft. The method is characterized in that: an error separation technique of three-point method is combined with a holographic spectrum technique, roundness error of a vibration signal is separated by the error separation technique of three-point method, and the dynamic balancing identification is performed on actual locus of journal center of the main shaft by holographic spectrum dynamic balancing theories, which effectively eliminates interference caused by the roundness error of a measured sectionto unbalance calculation and improves balancing precision and efficiency. Compared with the traditional 'holographic dynamic balancing method of rotators', the improved holographic dynamic balancingmethod can be used for qualitative error separation and unbalance error identification of the main shaft with the roundness error and fluctuant operating speed, unbalance measurement and estimation ofthe main shaft and establishment of a balancing plan, and have very high application value in improving efficiency of failure examination, reducing uncertainty of repetitive balancing operations andthe like.

The invention discloses a monocular vision positioning-based rotor unmanned aerial vehicle attitude estimation method, which comprises the following steps of: firstly, preprocessing an image which iscaptured by an airborne camera and contains a visual mark, eliminating image noise and highlighting the visual mark; According to the geometric characteristics of the visual mark, extracting the visual mark composed of an H-shaped mark and a circular ring through a five-step method; Then, detecting 12 corner points of the H-shaped mark by adopting a distance three-point method, and matching the 12corner points with corresponding corner points in a preset reference image; And finally, calculating a homography matrix according to the matched angular point pairs, decomposing the homography matrix by adopting a direct linear transformation DLT method to calculate an attitude angle of the unmanned aerial vehicle relative to the visual sign, and calculating position data of the unmanned aerialvehicle relative to the visual sign according to a similar triangle principle of camera imaging. The method is higher in calculation speed and has a better practical value.

The invention relates to a step-by-step calibration method for the camera parameters of a binocular stereoscopic vision system and belongs to the field of image processing and computer vision detection, which relates to a step-by-step calibration method for the camera intrinsic and external parameters of a dimension measurement system for large-scale forgings. According to the calibration method, firstly, the intrinsic parameter matrix of a camera is calibrated in the off-line manner in a laboratory, and the camera is driven to conduct two sets of mutually independent triorthogonal motions by a high-precision electric control platform. Secondly, based on the properties of FOD points, the intrinsic parameters of the camera are listed through the unique solution of a linear equation. At a forging experiment site, a basic matrix between two images is figured out through the 8-point method, and the method of decomposing of an essential matrix is conducted. In this way, the real-time on-line calibration for the external parameters of the camera is realized. Finally, based on the image information, the length of a high-precision three-dimensional scale is reconstructed, so that the solution of a camera scale factor is realized. The above method is simple and convenient in calibration process, short in calibration time and high in precision. The calibration of the camera of the binocular vision measurement system at the forging site can be precisely realized by adopting fewer images.

The invention discloses a visual inspection method for chip electronic component position error based on edge fitting. The method is that a boundary contour point set of an entire image is obtained by adopting boundary following to generate the edge point chain structure of the image; the image center a chip electronic component is preliminarily calculated by adopting a contour gravity center method, a corner is roughly calculated by adopting a closest-to-center point method, two lines which pass through the image center and are perpendicular to each other are established, the two lines divides the image contour into four areas containing corner points, four corner points are obtained in each area respectively according to the distance from a point to the center and four line sides are formed, and the corresponding edge point set is extracted by using the four line sides to partition an edge; and the edge fitting is conducted to each edge point set by adopting an edge point set rectangle least square method to obtain the fitting rectangle of the edge, and the center coordinates of the fitting rectangle and the corner relative to a horizontal direction are calculated. The invention has the advantages that the center position and the corner of the chip surface mounting component can be accurately inspected and the calculation speed is fast.

The invention provides a working modal identification method based on time-frequency domain single-source-point sparse component analysis. The working modal identification method specifically includes the following steps that vibration signals of an equipment target position under the working state are obtained through measurement; time-frequency domain conversion is conducted on the mixed vibration signals; a single-source-point method is used for extracting the mixed vibration signals used for estimating a hybrid matrix in a time-frequency domain; a hybrid matrix estimation method based on K hyperline clustering sparse component analysis is used for estimating the hybrid matrix; after the hybrid matrix is solved, the time-frequency domain is returned, the l1 minimization method is used for reconstructing each order of source signals, and modal vectors of a structure are extracted; then the working modal frequency and the damping ratio are obtained through signal index expression. According to the method, the calculation amount in the hybrid matrix estimation process is reduced, under the poor condition that the number of measuring points is less than that of the source signals, modal parameters are identified effectively, and the method has good anti-interference capacity for incomplete sparsity of noise, abnormal values and the source signals.

The invention discloses a method for acquiring high-precision atmosphere data of an aircraft flying across an atmospheric layer. The method is based on conventional airspeed head measuring techniques and embedded atmosphere measuring measures, and atmosphere test data meeting the requirements of the aircraft flying across the atmospheric layer are accurately and rapidly acquired through system model creation, redundancy design, temperature compensation design, data fusion and the like. A redundancy design technique based on arrangement of pressure measuring points of multipoint-pressure-measurement pressure sensors and an effectiveness selection strategy of a three-point-method calculation model are mainly adopted, and reliability in data acquisition during breakdown of pressure taps is realized; a temperature compensation design technique is provided, so that the problem of pressure measurement change caused by air specific heat change at a high temperature is solved, and pressure measurement precision is improved; atmosphere data measuring measures based on different parameter measurement modes are adopted, data fusion is performed on measured data, and input is provided to a solution model of trans-atmospheric atmosphere data.

The invention relates to an on-line measurement method for an axis orbit of a main shaft under cutting condition of a numerical control lathe. The on-line measurement method comprises the following steps of arranging three displacement sensors on a to-be-measured circular surface along the circumferential direction of the main shaft, collecting displacement signals and main shaft rotary angle signals before cutting, converting into rotary angle interval sampling signals, adopting a three-point method to separate the contour error of the to-be-measured circular surface, extracting the displacement signals of the two vertical displacement sensors, and calculating the installation eccentric error; according to the contour error and the installation eccentric error, obtaining an interference signal guided by the to-be-measured circular surface; under the cutting condition, adopting an interpolation method to calculate the interference signal corresponding to the main shaft rotary angle signal, removing the interference signal from the displacement signal under the cutting condition, and obtaining the axis orbit of the main shaft. The method has the advantages that the influence on the separation calculation by the speed fluctuation of the main shaft is avoided, the requirements of separation accuracy and rotary error quick separation are met, and the on-line quick separation of the rotary error is realized.

The invention discloses a similarity mining method of similar behaviors between multiple views and a behavior recognition method. The behavior recognition method is based on the similarity mining method. The similarity mining method comprises calculating a Hessian matrix response of every pixel in every frame of gray images of video streaming of different views of the similar behaviors frame by frame; determining feature points according to the matrix responses; building space-time feature descriptors of the feature points and obtaining posture description vectors after dimensionality reduction; calculating a similarity recurrence plot matrix with the posture description vectors as low-level features; and obtaining recursiveness descriptors according to the recurrence plot matrix and clustering the recursiveness descriptors. According to the similarity mining method of the similar behaviors between the multiple views and the behavior recognition method, posture modeling is achieved through a space-time feature point method and recursive similarity between the multiple views is mined through a recurrence plot, so that the problem that background segmentation dependency is easy to cause distortion of human body postures is solved and the accuracy of similarity mining and the robustness of behavior recognition are improved.