928 results about "Intersection of a polyhedron with a line" patented technology

Apparatuses, methods and computer program products for scan plane geometry definition in tomographic data acquisition via an interactive three-dimensional (3-D) graphical operator interface. The apparatuses, methods and computer program products are initially proposed for use in cardiac MRI, but have a much broader area of application. The apparatuses and methods utilize 3-D computer graphics aspect views of slice planes to show a new scan, represented as semi-transparent uniformly-colored planes. Intersections of these planes with opaque texture-mapped gray-level views of previously acquired images enable the orientation of a new scan to be viewed in a much more intuitive fashion. Advantageously, the apparatuses and methods of the present invention provide for more efficient elimination of positional ambiguity that is often associated with conventional 2-D intersection line views. In addition, any misregistration between localizer scans can be detected immediately in the integrated 3-D display by misalignment of anatomy in the previously acquires image planes.

The invention relates to a vector-relation-based method for calibrating single-line laser radar and a CCD camera. Point set information of the laser radar for scanning a V-shaped target is extracted in a laser coordinate system, and direction vectors and intersection coordinates of straight lines in two different planes of the target are obtained by means of straight line fitting; the CCD camera is used for capturing images in a camera coordinate system, target plane equations and an equation of a plane passing through an original point and laser radar scanning lines are obtained by processing image information, a straight-line equation of laser radar scanning is built, and furthermore, the direction vectors and the intersection coordinates of the straight lines are obtained; finally, calibration is finished according to the relations between direction vectors and the intersection coordinates of the straight lines corresponding to the different coordinate systems. According to the method, no object in a calibration scene needs to be moved, collection of all calibration data can be completed at a time, and calibration efficiency is improved greatly. According to the method, the direction vectors of the straight lines of the laser scanning target planes under the coordinate systems of sensors to be calibrated are obtained directly, calibration precision is guaranteed, and meanwhile the calibration algorithm is simplified.

A time-series data classifying apparatus may include a first database, a peak feature extracting unit, a second database, a data input unit, and a predicting unit. The first database stores a plurality of cases each including time-series data a classification label. The peak feature extracting unit may, for each of the cases, calculate intersection points of time-series data expanded in a coordinate system and each reference line, detect a peak point in each of sections formed between two intersection points being adjacent to generate a peak feature sequence that contains a sequence of detected peak points. The second database may store each peak feature sequence in association with a classification label of each of the cases. The data input unit may input target time-series data. The predicting unit may predict a classification label to be assigned to the target time-series data based on the second database.

The invention discloses a calibration method of correlation between a single line laser radar and a CCD (Charge Coupled Device) camera, which is based on the condition that the CCD camera can carry out weak imaging on an infrared light source used by the single line laser radar. The calibration method comprises the steps of: firstly, extracting a virtual control point in a scanning plane under the assistance of a cubic calibration key; and then filtering visible light by using an infrared filter to image infrared light only, carrying out enhancement, binarization treatment and Hough transformation on an infrared image with scanning line information, and extracting two laser scanning lines, wherein the intersection point of the two scanning lines is the image coordinate of the virtual control point in the image. After acquiring multiple groups of corresponding points through the steps, a correlation parameter between the laser radar and the camera can be solved by adopting an optimization method for minimizing a reprojection error. Because the invention acquires the information of the corresponding points directly, the calibration process becomes simpler and the precision is greatly improved with a calibrated angle error smaller than 0.3 degree and a position error smaller than 0.5cm.

The invention discloses a concave convex mixed complex polygon farmland unmanned aerial vehicle spraying operation flight path planning method. Starting from any feature point on the boundary of the polygon farmland, all feature points of the boundary of the polygon farmland are acquired sequentially, adjacent two points are connected by using a straight line sequentially according to the point acquisition sequence of the feature points, and an operation region of the boundary of the polygon farmland is generated; the longest edge of the boundary of the operation region is found out; a feature point farthest from the longest edge is found out; N flight path lines are drawn between the longest edge and the feature point farthest from the longest edge; coordinates of all boundary line segments crossed with the flight path lines and flight path line crossed points are obtained; the number of the crossed points between the flight path lines and the boundary line segments is judged, and when the number of the crossed points is larger than 2, flight path lines outside the operation region range are deleted; and starting from a flight path line nearest to the longest edge, the flight path lines and side flight lines are connected in sequence, and an S-shaped flight path planning line is obtained. The flight path of the concave convex mixed complex polygon farmland unmanned aerial vehicle spraying operation can be planned.

A method of creating an obstacle-free diagram using topological sensor data to form a graph corresponding to a driving path, transforming the graph using discrete heuristics, locally smoothing a plurality of edges of the graph after the transforming, and globally smoothing the graph after the locally smoothing. Transforming includes deleting an edge of the graph, merging two intersections of the graph into a single intersection, and collapsing a plurality of edges forming a loop into a single edge. Locally smoothing includes smoothing a lane segment of the graph by minimizing a sum of a function of smoothness and a function of distance. Globally smoothing includes defining an intersection potential and minimizing a sum of the function of smoothness, the function of distance, a function of intersections and a function of direction.

The invention provides calibration method, device and calibration phantom of the geometric parameters in a CT (computer tomography) system. In the method, the calibration phantom is placed on a rotary table positioned between a light source and a detector, the calibration phantom comprises a calibration plate, as well as a small ball A and a small ball B which are arranged on the calibration plate, the calibration phantom is rotated for a circle along with the rotary table, and a center point coordinates of projection images of the small ball A and the small ball B are collected by the detector; the coordinate of an intersection point of a projective point line of projection ellipses of the small ball A and the small ball B is calculated and obtained according to the center point coordinates of the projection images and and the center coordinates of the projection ellipses of the small balls, and the torsion angle of the detector, the distance from the light source to the detector, the projection center point coordinate of the light source on a imaging plane, the swinging angle of the detector and the distance from the light source to the rotary table can be calculated based on the coordinate of the intersection point of the projective point line and a elliptic equation. The invention can calibrate a plurality of parameters, and can sufficiently meet the requirement of subsequent CT image correction.

The invention discloses a second-level sight line tracing method based on face orientation constraint. The method comprises the following steps that: obtaining an image sequence; detecting face area and eye area image information; solving a face orientation, taking the face orientation as a ray direction, and defining the ray direction as a standard watching direction; intersecting the ray of the standard watching direction with an equipment screen to obtain a point of intersection, and taking the point of intersection as a standard watching point; taking a screen area delimited by taking the standard watching point as a center as a constraint field of view; and analyzing the eye area image information to obtain the watching area of the user on the constraint field of view. By use of the method, according to the physiologic habits of human eye for observing objects, head shaking is taken as effective sight line tracing information, and a head gesture is preferably considered. By use of the method, a calibration step is omitted, head movement compensation is not required, and true no-constraint sight line tracing can be realized.

This invention relates to laser high-accuracy three-dimensional coordinate measurement, which in detail relates to a binocular structure photo-sensor compatibility calibration and its operation apparatus. In order to calibrate the photo plane parameters of the binocular structure photo-sensor, it unites the space coordinates measured of the left and right cameras. The technique project adopted in this invention is the following: the operation apparatus comprises left and right cameras, laser machine, and target and also movable guide rail with the target fixed on; the target plane is vertical to the moving direction of the guide rail which ensures the plane is vertical to the project laser plane. Besides, it is to identify the axis coordinates in the space coordinate system of the cross points of the each lines and photo bars in the target and brings the coordinates to the photo-sensor mathematical model for computation and get sensor parameters.

A method for representing virtual information in a view of a real environment is provided that includes the following steps: providing a system setup comprising at least one display device, determining a position of a viewing point relative to at least one component of the real environment, providing a geometry model of the real environment, providing at least one item of virtual information and its position, determining a visualization mode of blending in the at least one item of virtual information on the display device according to the position of the viewing point and the geometry model, calculating a ray between the viewing point and the item of virtual information, and determining a number of boundary intersections by the ray, wherein if the number of boundary intersections is less than 2, the item of virtual information is blended in a non-occlusion mode, otherwise in an occlusion mode.

The invention relates to a system calibration method based on depth information. The method includes: firstly utilizing a circular plane target, extracting a feature point sub pixel outline by adopting self-adaptive threshold value edge detection and a multinomial fitting algorithm, and obtaining a central coordinate by using ellipse fitting; working out the optimal solution of a camera parameter by using a least square method according to a nonlinear imaging geometric model with distortion to obtain the pose of the target; at least providing depth information between the surface of an object to be detected and the target plane as the correction item of the camera model for correcting the pose of the measurement plane, and determining parts dimension by using an imaging principle and a point of intersection of a straight line with the parts surface; according to the system calibration method based on depth information, the problem that the dimension measuring system for the large-dimension plane parts is not high in calibration precision, thus being worthy of popularization and application.

There is provided a method and a system for registration of real time position of tennis ball relatively to boundary lines on tennis court. The method and system comprise sensitive to near-infrared radiation at least one video camera, outputting video image of court and the method and system further include at least one point source of near-infrared radiation, illuminating tennis court and displaced relatively to the video camera. It is suggested a simple and inexpensive way of determining if a tennis ball bounces in or out of court by determining point of intersection of trajectories of the tennis ball and its shade from near-infrared radiation and comparing the position of the determined point of intersection with previously calibrated boundary lines of court.

The invention relates to a mobile robot path planning method based on improved A-star algorithm, and belongs to the field of mobile robot path planning. The method is as follows: firstly performing global path pre-planning in a static obstacle environment; then performing secondary smoothing on path points of the global path pre-planning to obtain a pre-planned path; and finally adopting an artificial potential field method and a method for global path pre-planning in the static obstacle environment to perform local path planning when encountering a dynamic obstacle. The method is no longer limited to points in a grid. In a path-finding process, a current node and an extended node are connected, and the obstacle is detected by judging whether a route point connection line and an obstacle edge have intersections.

The invention discloses an identification method and system of lateral deviation of a vehicle driving route. According to the method and system, firstly, an image, which is shot by a camera mounted ona vehicle, of a road along a vehicle running direction is acquired; an internal-parameter matrix of the camera is utilized to carry out de-distortion processing on the video frame, and inverse perspective transformation is carried out on a selected to-be-transformed region src; then threshold segmentation is carried out on the video frame to separate lane lines from a background region; then locations where maximum values appear are derived by counting to use the same as intersection points of the lane lines and the bottom of the image; and whether correction of lateral deviation of the driving route needs to be carried out is judged according to separation distances between the locations of the intersection points and a preset lateral mounting location of the camera on the vehicle. In acase where the vehicle deviates from a road center too far, the method and system can know the case in time, and remind a driver or carry out correction; and the method and system can accurately detect all of sudden illumination changes, tree shade shading, road surface stains and many other conditions, and are high in applicability, low in costs, high in precision and better in real-time performance and stability.

According to an angular point positioning method and apparatus which are provided by the present invention, firstly, an interest area on a target image is subjected to edge detection to acquire a plurality of edge pixel points, then the plurality of edge pixel points are partitioned into two fit areas according to preset rules, coordinates of each edge pixel point in each fit area is subjected to linear fitting to obtain two fitting straight lines and finally, angular point coordinates can be obtained by calculating a point of intersection of two fitting straight lines, and thus, in the image matching process, the required angular point position can be accurately positioned without manually presetting an offset and not only the manual operation is reduced, but also accuacy of angular point positioning and image matching is greatly promoted, so that system accuracy of a mechanism is promoted.

The invention discloses a method for reconstructing an outer outline polygon of a building based on multivariate data. The method comprises the following steps of: respectively dividing DSM (Design Standards Manual) data and image data so as to obtain a mask image of an interest region of the building and an image dividing object; combining the mask image with the image dividing object so as to obtain a complete building object; carrying out boundary tracing on the building object so as to obtain curves of the building; using points corresponding to local maximum curvature values of the curves as angular points; connecting the angular points in sequence so as to obtain the outline polygon of the building; dividing the building object into regions by using a hierarchical clustering method and calculating the main direction of the building; establishing a linear model of the polygon of the building and correcting and regularizing the linear model of the outline of the building with the combination of the main direction of the building and gradient information of the image data; calculating an intersection point of every two adjacent straight line sections by using the linear model of each line section of the polygon; and by taking the intersection points as the angular points, connecting the angular points in sequence so as to form the final polygon of the building. According to the method, the DSM data is organically combined with the image data, the data are complementary to each other in the whole process, so that the problem of reconstructing the polygon of the outline of the building is solved well, and the method has very strong robustness in the two-dimensional outline modeling aspect of the building.

Systems and techniques are described for ray tracing and for the efficient construction of acceleration data structures required for fast ray tracing. A computer graphics system generates, for each pixel in an image, a pixel value that is representative of a point in a scene as recorded on an image plane of a simulated camera. The computer graphics system is configured to generate the pixel value for an image using a selected ray-tracing methodology. The selected ray-tracing methodology includes the use of a ray tree that includes at least one ray shot from the pixel into a scene along a selected direction. The ray-tracing methodology further includes calculating the intersections of rays and surfaces in the scene. An axis-aligned bounding box is defined that contains, for a given ray, the point of intersection of the ray and surface nearest the origin of the ray. The bounding box is iteratively refined until a predetermined termination criterion has been met.

The invention provides an optimization design method of a low-orbit communication and navigation enhancement mixed constellation. The method comprises the following steps: determining a satellite orbit type; determining a satellite orbit height; determining a minimum observation elevation angle; selecting constellation configuration; determining an orbit inclination angle; determining a satellite quantity; determining an orbit surface quantity and a phase factor; selecting initial ascending node right ascension in an optimized mode; analyzing coverage performance of the low-orbit communication and navigation enhancement mixed constellation; and after traversing ends, comparing all mixed constellation parameters satisfying design requirements, and selecting an optimal solution. The method has the following advantages: through combination of factors needing to be considered for design of a communication and navigation enhancement constellation at each phase, the designed low-orbit communication and navigation enhancement mixed constellation can satisfy user demands, is excellent in constellation performance, is small in satellite quantity and quite good in compatible mutual operation capability between constellations.

The invention discloses a full-parameterization establishing method for a road three-dimensional model. The road design process is taken as the start, and design parameters of cross and longitudinal sections of a road are taken as the input. Specific establishing steps include that a plane straight curve is stretched and expanded to form a longitudinal section, a road longitudinal section straight curve is established and folded to form a road center line, ultrahigh and widened cross sections are arranged at transition feature points to form road subgrade surfaces, side lines are extracted to be crossed with terrain, filling and digging segments are judged, filling and digging sections are automatically generated through an intersection point ray method, digging faces and slope filling faces are formed, the filling and digging operation is conducted, and the road three-dimensional model is generated. According to the full-parameterization establishing method for the road three-dimensional model, the defect that input parameters are undefined in significance in an existing design process is overcome, and the full-parameterization establishing method has the advantages that the fast response to design changes is achieved, road three-dimensional design calibration is achieved, earthwork calculation is achieved, road path planning comparison and selection are achieved, and virtual wandering is achieved.

The invention discloses a rescue robot three-dimensional environment map real-time construction method. According to the method, an efficient speeded up robust feature (SURF) algorithm is adopted to carry out recognition and matching of feature points; next, an interval analysis method is proposed, roughly matched pose transformation matrixes are generated. The method has good robustness and can contain all possible values under the situation that one set of constraint conditions are given. In order to overcome the defect that the iterative process probably can not converge the globally optimal solution through an ICP algorithm, an improved closest point select method is proposed: for a measure point in a point cloud A, three points, closest to the measure point, in a point cloud B are solved to form a plane, an intersection of normal vector passing the measurement point in the plane and the plane is regarded as the closest point, and consequently the accuracy of the algorithm is well improved. In addition, the approach combining an inertial management unit (IMU), odometer data and the pose transformation matrixes is adopted, so that the algorithm has better robustness, and accurate location can be achieved under the condition that feature point matching is unsuccessful or the environment dynamically changes.

The invention discloses a heterology remote sensing image registration method. According to the core idea, multi-scale matching is taken as a basis; straight line intersection points are used as elements; the point matching method of a joint Voronoi map and a spectrogram is used; iteration feature extraction and a matching policy are integrated; and the problems of heavy dependence on feature extraction, poor reliability, low accuracy and the like of the existing method are overcome. The method comprises the steps that multi-scale analysis is carried out on original images; straight line extraction and intersection point acquiring are carried out on the coarsest scale; the point matching method of the joint Voronoi map and the spectrogram is carried out on intersection point sets to acquire a homonymous point pair; whether a matching result is qualified is detected: if the matching result is qualified, going to the next step is carried out, otherwise self-adaptive parameter adjustment is carried out and straight line extraction and point set matching are carried out again; original transformation is carried out on the images to be registered, and straight line features are respectively extracted; homonymous straight line segments are searched, and a candidate homonymous point pair is acquired; a KNN map is used to acquire an accurate matched point pair; and a transformation parameter is solved. The method provided by the invention is mainly used for the registration of visible light, infrared, synthetic aperture radar (SAR) and other heterology remote sensing images.