441 results about "Spherical coordinate system" patented technology

A computer input device constructed from at least one tilt accelerometer and at least one linear input element is disclosed. This input device can be used in a computer system to specify a position on a display using radial coordinates, cylindrical coordinates, or spherical coordinates.

An apparatus for interfacing the movement of a shaft with a computer includes a support, a gimbal mechanism having two degrees of freedom, and three electromechanical transducers. When a shaft is engaged with the gimbal mechanism, it can move with three degrees of freedom in a spherical coordinate space, where each degree of freedom is sensed by one of the three transducers. A fourth transducer can be used to sense rotation of the shaft around an axis. The method includes the steps of defining an origin in 3-dimensional space, physically constraining a shaft in the 3-dimensional space such that a portion of the shaft always intersects the origin and such that a portion of the shaft extending beyond the origin defines a radius in a spherical coordinate system, transducing a first electrical signal related to a first angular coordinate of the radius with a first transducer, transducing a second electrical signal related to a second angular coordinate with a second transducer, transducing a third electrical signal related to the length of the radius with a third transducer, and coupling the transducers to a computer.

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 novel detachable pole caddy that is universally positionable by operating in a spherical coordinate system, and method for positionally adjusting the detachable pole caddy within the spherical coordinate frame. According to one aspect of the invention the novel detachable pole caddy is provided by two releasably interlockable rotationally and spherically rotatable ball-and-socket components that are formed between a substantially rigid spacing component and two part-spherical couplers. A pole clamp mechanism is coupled to one of the two part-spherical couplers, and a caddy is coupled to a different one of the two part-spherical couplers.

The invention discloses a simple and feasible calibration method for the relative attitude of a binocular stereo camera and an inertial measurement unit on the basis of the absolute gravity direction. The method comprises the steps that a gravity direction vector serves as a reference vector, expressions of the gravity direction vector under a camera coordinate system and under an IMU coordinate system are solved respectively to obtain the expressions of the same vector under the two different coordinate systems, and then the attitude change relationship between the two coordinate systems can be solved; finally, precision verification is performed through reprojection errors, and application of the calibration method in a visual odometer is supplied. Experiments show that the relative attitude between the camera and the IMU can be accurately solved through the method. The method can be used for assisting in vision positioning of mobile robots and spherical robots.

A novel universal detachable presentation bracket that is universally positionable by operating in a spherical coordinate system, and method for positionally adjusting a presentation device on the bracket within the spherical coordinate frame. According to one aspect of the invention the novel universal detachable presentation bracket is provided by two releasably interlockable rotationally and spherically rotatable ball-and-socket components that are formed between a substantially rigid spacing component and two part-spherical couplers. A suction cup clamp mechanism is coupled to one of the two part-spherical couplers, and a retention being coupled to a different one of the two part-spherical couplers.

An image capturing apparatus includes a tilt detection unit that detects a tilt in the vertical direction, conversion data used for transforming plane coordinates into spherical coordinates, a correction unit that corrects the conversion data according to the tilt, a plurality of image capturing units, a coordinate transformation unit that transforms plane coordinates of a plurality of pixels included in images captured by the image capturing units into spherical coordinates according to the conversion data corrected by the correction unit, and a combining unit that combines the images including the pixels transformed into spherical coordinates by the coordinate transformation unit.

The invention provides a stereo street scene video projection method. The method comprises the following steps: S11, obtaining a panorama video stream of a street scene; S13, decomposing the panorama video stream to multiple frames of street scene images and projecting the images to a spherical coordinate system; S15, superposing the multiple frames of street scene images, and establishing video stream channels among the multiple frames of street scene images; and S17, on the spherical coordinate system, continuously playing the multiple frames of street scene images according to the video stream channels. The invention further provides a stereo street scene video projection system. By using the stereo street scene video projection method and system, real-time images can be obtained simply by use of a camera without specially photographing panorama photographs of specific places, latest data can be monitored, updated and obtained without regular plotting, the panorama photographs are replaced by videos obtained through the camera, and the containing information is quite rich.

The invention relates to a method for generating three-dimensional imaging original echoed signals of chromatography synthetic aperture radars, which comprises the following steps: taking a three-dimensional image containing backward plural scattering coefficients of imaging area targets in a rectangular coordinate system OXYZ as the input, carrying out three dimensional fourier transform on the three-dimensional image and converting an image signal to a rectangular coordinate system wave-number domain; converting signals in Kx, Ky and Kz domains to be signals in Kw, Ku and Kv domains according to the method of converting the rectangular coordinate system to a spherical coordinate system; introducing imaging geometrical relationships among same imaging area of chromatography synthetic aperture radars by multiplying three dimensional filter function H2 (Kw, Ku and Kv); introducing a transmission signal form by the multiplication of a two-dimensional inverse Fourier transform function and a reference phase function; and at last, by W direction process and other operations, obtaining the three-dimensional imaging original echoed signals of chromatography synthetic aperture radars, which contains a carrier frequency. The method can be used for generating three-dimensional imaging original echoed signals of side-looking, downward-looking, forward-looking, backward-looking and downward side-looking chromatography synthetic aperture radars, and has high echo generating efficiency and easy realization of modularization.

The invention provides a coarse alignment method for a fiber optic gyro strapdown inertial navigation system based on single axis rotation. The coarse alignment method comprises the following steps: (1) determining initial position parameters of a carrier by a GPS; (2) collecting the data output by a fiber optic gyroscope and a quartz accelerometer and processing the data; (3) determining a transfer matrix Ti<n> of a navigation coordinate system and an inertial coordinate system according to the mutual position relation of the coordinate systems; (4) allowing a single axis of an inertial measurement unit to continuously rotate, setting superposition of an initial time IMU coordinate system s and a carrier coordinates b, then allowing the inertial measurement unit to continuously rotate around a positive direction of an azimuth axis ozb of the carrier coordinate system with an angular velocity Omega=6 degrees/s; (5) determining the relative position relation of the inertial coordinate system and a base inertial coordinate system; and (6) determining an expression of a strapdown matrix after coarse alignment is over according to the calculated relative conversion relation of the coordinate systems calculated in step (3), (4) and (5). The coarse alignment method can help obtain higher coarse alignment precision under a swinging interference condition.

A method for using visual marker point to locate the 3D object to be connected includes such steps as creating a coordinate system of probe by 4 marker dots, determining the coordinate of probe tip in the coordinate system, calculating the relation between the coordinate systems of world and probe, and coordinate transforming to obtain the coordinate information of probe tip in world coordinate system.

The invention belongs to the field of radar target tracking, and specifically discloses an interactive multi-model radar target tracking method based on predicted value measurement conversion. The interactive multi-model radar target tracking method combines a measurement conversion covariance matrix based on a predicted value with a Kalman filter based on interactive multiple models in a spherical coordinate system, and realizes maneuvering target tracking. Parameters (including estimated prediction distance, azimuth angle, pitch angle and corresponding estimated prediction error covariances) related to a measurement conversion covariance are obtained according to a covariance matrix of an estimated position predicted value in a rectangular coordinate system and position prediction errors obtained by means of the filter, and through nonlinear transformation and a Jacobian transformation matrix. The interactive multi-model radar target tracking method overcomes the inherent defects of a measurement conversion algorithm, and has tracking precision higher than that of an EKF-IMM.

The invention provides a master-slave tracking method for a binocular PTZ (Pan-Tilt-Zoom) visual system and a system applying the method. The master-slave tracking method comprises the following steps of: respectively calibrating two PTZ cameras, thereby obtaining camera coordinate system models; establishing a spherical coordinate system, enabling longitude values of corresponding points on two PTZ camera coordinate systems to keep consistent on the spherical coordinate system, expressing visual angle differences by using latitude differences, and respectively obtaining transformation matrixes from the two PTZ camera coordinate systems; and deciding on a master camera and a slave camera, selecting a tracking object from observation images of the master camera, and enabling the master camera to estimate PTZ parameters (Pts, Tts and Zts) of the slave camera at any PTZ parameters (PM, TM and ZM); and outputting a high-resolution panoramagram. The master-slave tracking method provided by the invention can realize the monitoring on wide-range scenes and can reduce hardware overhead. According to the master-slave tracking system provided by the invention, the two PTZ cameras are of a symmetrical design, the positions of the two PTZ cameras can be exchanged according to different tasks, the flexibility is strong, and the subsequent information fusion is favored.

The invention discloses a control method of brushless D.C. motor (BLDC) position signal phase error based on back EMF zero crossing point reconstruction, belonging to the technical field of the control method of BLDC non-position sensor technology. The method comprises the following steps: respectively collecting three phases of filtered terminal voltage waveforms, the coordinate systems thereof being alfa coordinate system in which vectors of three axels in the alfa coordinate system are used for representing three filtered terminal voltages, calculating the projection of the three vectors of the alfa coordinate system in the belta coordinate system. The degree beta by which the belta coordinate system lags behind the alfa coordinate system is controlled to achieve real-time compensation for the error of position signal phase caused by RC first order low pass filtering, and the zero-crossing points of the three vectors in the belta coordinate system are phase-changing points, thus realizing accurate phase-changing. The invention can avoid being affected by RC filtering under the working condition of broad rotating speed.

The invention discloses an image registration method based on a synthetic aperture radar (SAR) image and digital elevation model (DEM) data, wherein the problems that the positioning precision to ground target points in SAR image is not high and positioning is difficult to realize in actual projects in the prior art are mainly solved. The method comprises the following steps of: solving a longitude L, a latitude B and an elevation value h' of a ground target point in a spherical coordinate system by using a steepest descent method according to the Range-Doppler (RD) principle and the earth model equation, and transforming the values into a geodetic coordinate system; looking up the elevation value h' corresponding to B and L in a DEM database, and comparing the absolute value of h'- h' with a set threshold value epsilon, if the absolute value of h'- h' is greater than epsilon, enabling h to be equal to h' and returning to resolve the equation system again, and if the absolute value ofh'- h' is identical to or less than epsilon, stopping iteration, and taking h' as the elevation value of the ground target point, and the corresponding latitude B and longitude L as the latitude and longitude of the ground target point; linearly correcting the longitude and latitude to eliminate system errors, so that a final ground target point positioning result is obtained. The image registration method disclosed by the invention has the advantages of small operand and high positioning precision, and can be used for positioning ground target points in SAR images in actual projects.

A shape data specifies the shape of an elongated product within an overall coordinate system. Local coordinate systems are defined on respective cross-sections of the elongated product in the overall coordinate system. The local coordinate system is designed to represent a stable die of a bending apparatus. The images of the elongated product protruding forward from the stable die within the respective local coordinate systems serve to specify the position of a movable die of the bending apparatus. The specified position reflects the deformation induced in the elongated product between the stable and movable dies. An ideal movement amount of the movable die can be determined based on the determined positions within the local coordinate systems. The determined movement amount can be utilized to prepare the control data for the bending apparatus. When the prepared control data is supplied to the bending apparatus, an ideal movement of the movable die can be achieved so as to effect bending on the elongated workpiece at a higher accuracy in accordance with the shape data.

The invention discloses an ultrasonic surgery auxiliary navigation system based on binocular vision, and belongs to the field of vision positioning technology. According to the invention, on the basis of the binocular vision positioning technology, a binocular vision positioning device and an ultrasonic probe are fixed together by a coordinate system calibration device, meanwhile points under the world coordinate system are subjected to imaging, coordinates of the imaging in the respective coordinate systems are calculated, then the transformational relation of the respective coordinate systems is calculated, and surgical instruments and foci are fused by the transformational relation in the same three-dimensional coordinate system for display in an image work station. The technical scheme of the invention overcomes the problems of conventionally, a puncture intervention surgery cannot be guided continuously in real time and the operation is not flexible and convenient enough, the surgery auxiliary guidance is carried out by using the positioning device based on machine vision and by an image processing algorithm, and the whole system has the advantages of high speed, high precision, small occupation space and so forth.

The invention discloses a spherical space division-based coronary artery automatic segmentation and anatomic marking method. The method comprises the following steps of (1) performing image preprocessing: obtaining a coronary artery segmentation image and a central line; (2) performing a pruning operation; (3) defining a spherical center and a spherical space; (4) executing a division rule of left and right coronary arteries; (5) executing a left coronary artery anatomic naming algorithm; and (6) executing a right coronary artery anatomic naming algorithm. According to the method, a spherical coordinate system is established by taking a vessel divergence point as the spherical center through utilizing characteristics of a heart-shaped inverted cone, and the blood vessel is located and dissected in the spherical space according to anatomic shapes of branch segments of the coronary arteries and a geometric structure relationship among the anatomic shapes, so that the purposes of automatic segmentation and anatomic marking are achieved; the problems of relatively long calculation time, relatively high algorithm complexity and inaccurate branch matching caused by incapability of exhausting coronary artery distribution types in an existing coronary artery automatic segmentation and anatomic marking method are solved; and compared with a method for matching the extracted blood vessel with a prior model, the spherical space division-based coronary artery automatic segmentation and anatomic marking method has the advantages that the time is shortened, the marking is accurate, and more segments can be identified and marked.

The invention relates to a calibrating method of a laser dot-matrix device of an obstacle avoidance system of a lunar rover, which can effectively solve the problems on precisely calibrating the relationship between 18 laser beams in the laser dot-matrix device and a reference prism coordinate system of the laser dot-matrix device and the relationship between reference prism coordinate systems of an obstacle avoidance camera. The method comprises the following steps of: taking a photograph of a laser dot by using the camera; processing the image to obtain an image point coordinate; carrying out triangular surveying based on internal parameters of the camera to obtain a three dimensional coordinate; obtaining the three dimensional coordinate of the laser dot under a double-camera photographic surveying system by using the processed photograph; establishing the relationship between marked points on the double cameras and a bracket and the coordinate system, the coordinate of the laser dot under a bracket marked point coordinate system and a theodolite coordinate system; establishing the relationship between the theodolite coordinate system and the bracket marking point coordinate system and the relationship between the theodolite coordinates and the reference prism coordinate system of the dot-matrix device; and then establishing the coordinates of the laser dot under the theodolite coordinate system and the reference prism coordinate system. The invention has the advantages of fast calibrating speed and high accuracy, and can be effectively used in the fields of technological digital photogrammetry, computer vision and the like.

The invention provides a complex geometry image representation method for a point cloud curve surface. Surface attribute information and geometry information of the point cloud curve surface are mapped into a two-dimension image through a spherical polar coordinate. According to the method, firstly, the Cartesian coordinates [x, y, z] are converted into the spherical polar coordinates [gamma, phi, theta] through the spherical coordinate. Two quantities in the coordinates [gamma, phi, theta] are respectively converted into pixel coordinates, and the other one coordinate is converted into a gray value of the pixel, so that three different geometry images gamma (phi, theta), theta (gamma, phi) and phi (gamma, theta) can be obtained. The geometry information loss can be caused when any one image in the three images is used for representing the point cloud curve surface, so that the complex geometry image representation method for the point cloud curve surface provided by the invention integrally uses the three image conversion modes, and the efficient and precise representation on the point cloud curve surface can be realized. When the method is used, the compression, the editing, the simplification, the model retrieval, the progressive transmission and the like on the point cloud curve surface can be easily realized.