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1094 results about "Calibration result" patented technology

Calibrating method of binocular three-dimensional measuring system

The invention provides a calibration method for a binocular stereo measurement system, and belongs to the technical field of measurement and test. The invention adopts a plane calibrating board having a characteristic dot array with an accurate given distance between the centers of two characteristic dots; the calibrating board is shot from more than three angles; initial values of the intrinsic and extrinsic parameters of two cameras are solved by using the linear method under a pinhole model; the distortion effect is considered; the intrinsic and extrinsic parameters of the two cameras are taken as optimization variables for a first optimization; the space coordinates of the centers of the characteristic dots on the calibrating board are taken as optimization variables for a second optimization; the translation vector between the cameras is scaled to the ratio of the calculated distance to the given accurate distance, thus getting a calibration result of the parameters; the result of the second optimization is got by using the intrinsic parameters and the relative attitude parameters of the two cameras. Considering the influence of the geometrical errors of the calibrating board, the method reduces the manufacturing, measurement and calibration requirement of the calibrating board and gets calibration result of high precision.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Method for measuring object deformation in real time

The invention discloses a method for measuring object deformation in real time, which comprises the following steps: arranging and adjusting measuring equipment, namely symmetrically arranging two cameras and corresponding LED illumination lamps above a measured object, and making optical axes of the two cameras intersected in a distance of 1 meter in front of the cameras; then calibrating the cameras, namely tightly sticking mark points to the surface of an object to be measured according to the size and shape of the measured object and the measurement requirement; next, placing the measured object stuck with the mark points under the two cameras in about 1 meter or moving the whole measuring equipment to make the measured object enter a measurement range and enable each camera to acquire the mark points on the surface of the measured object, starting the two cameras to shoot sequence images, and acquiring digital images; then identifying and positioning the images; reversely solving a projection matrix according to the calibration result of the cameras, and combining image coordinates of the solved mark points on the surface of the measured object on the images of the two cameras to reconstruct a three-dimensional coordinate of the mark points; and finally, carrying out deformation analysis and calculation for the mark points on the surface of the measured object.
Owner:XI AN JIAOTONG UNIV

Wide-baseline visible light camera pose estimation method

The invention relates to a wide-baseline visible light camera pose estimation method. The method includes the steps that firstly, the Zhang calibration method is used, and internal references of cameras are calibrated through a plane calibration board; eight datum points on a landing runway are selected in a public visual field region of the cameras and world coordinates of the datum points are accurately measured off line through a total station; in the calibration process, cooperation identification lamps are placed in the positions of the datum points and the poses of the cameras are accurately calculated through detection of the cooperation identification lamps. According to the method, the complex natural scene characteristic of an unmanned aerial vehicle landing scene and the physical light sensing characteristic of the cameras are considered, and glare flashlights are designed and used as the cooperation identification lamps of the visible light cameras; the eight datum points are arranged on the landing runway and space coordinates of the datum points are measured through the total station according to space accuracy at a 10 <-6> m level. According to the method, a calibration result is accurate and a re-projection error on an image is below 0.5 pixel.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Global calibration method based on binocular visual system and laser tracker measurement system

The invention discloses a global calibration method based on a binocular visual system and a laser tracker measurement system. Firstly a rigid stereoscopic target of which the A side is provided withbinocular visual system circular mark points and the B side is provided with laser tracker measurement target balls is manufactured; then the A side coordinate system and the B side coordinate systemof the stereoscopic target are established; the transformation relation between the A side coordinate system of the stereoscopic target and the left camera coordinate system of the binocular visual system and the transformation relation between the B side coordinate system of the stereoscopic target and the laser tracker world coordinate system are solved; the transformation relation between the Aside coordinate system and the B side coordinate system is solved according to the transformation relation solved in the last step; and finally the transformation relation between the left camera coordinate system of the global calibration binocular visual system and the laser tracker world coordinate system is solved. The difficulty of directly processing and maintaining the high-precision stereoscopic target can be reduced so that the measurement error caused by direct measurement can be solved and the more accurate calibration result can be acquired.
Owner:四川雷得兴业信息科技有限公司

Communication system, apparatus and methods for calibrating an antenna array

A method for calibrating (700) an antenna array comprises a plurality of antenna elements coupled to a plurality of respective receive paths in a wireless communication system. The method comprises, in receive mode, applying a test signal to an individual single receive path (715) of the plurality of receive paths; and feeding back the test signal via a switched coupler network. The method further comprises running a receive calibration measurement routine to determine at least one measurement value used to calibrate the individual signal receive path and waiting for at least one converged measurement value; and extracting (720) the converged measurement value for at least one individual receive path. The steps of applying, running, extracting for a next individual single receive path are repeated until the calibration routine has completed (725). The method further comprises selecting a converged measurement value of at least one individual receive path from a plurality of receive paths (730) to form a reference receiver calibration result (730); normalizing a plurality of at least one measurement values of the plurality of receive paths using the reference receiver calibration result (730); and applying a normalized value to at least one of the plurality of receive paths.
Owner:ANALOG DEVICES INT UNLTD

Large-scale MIMO (Multiple Input Multiple Output) antenna array far field calibration system

The invention discloses a large-scale MIMO (Multiple Input Multiple Output) antenna array far field calibration system. The calibration accuracy of a wave beam direction error caused by an array element position error and an amplitude phase error in an antenna array under test can be effectively increased by the calibration system. The calibration system is implemented by the following technical scheme: a server control device controls the relative position between the antenna array under test and a beacon antenna, and changes a wave beam incident angle from a transmitting beacon antenna to areceiving antenna array under test or a wave beam departure angle from a transmitting antenna array under test to a receiving beacon antenna; a phased array wave control device controls all phase shifters, attenuators, switches and digital weighting of a feed network of the antenna array under test; a data transmitting and acquiring device controls digital signals transmitted by the transmitting antenna array under test and the transmitting beacon antenna, and acquires digital signals received by the receiving antenna array under test and the receiving beacon antenna; and the array element positioning error and the amplitude phase error of the antenna array under test are calculated on the basis of a digital domain signal processing algorithm, and a calibration result of the antenna arrayunder test is output.
Owner:10TH RES INST OF CETC

Automatic calibration method for video monitoring system

The invention provides an automatic calibration method for a video monitoring system. The video monitoring system comprises a wide-angled camera namely a gun-type camera and a PTZ camera namely a ball-type camera, wherein the wide-angled camera is used for shooting a wide angled picture namely a gun-type camera picture in a large-scale field of vision, and the PTZ camera is used for shooting a local enlarged picture namely a ball-type camera picture in the large-scale field of vision. The automatic calibration method comprises a step of rough calibration and a step of specific calibration, wherein the rough calibration is that a mapping relation between a gun-type camera picture coordinate and a ball-type camera picture coordinate and a mapping relation between the ball-type camera picture coordinate and a ball-type physics coordinate are utilized to obtain a mapping relation between the gun-type camera picture and the ball-type physics coordinate, and the specific calibration is that a rough calibration result is rectified by utilizing of a ball-type light center picture coordinate. By means of the automatic calibration method, people can be liberated from a complex calibration operation, and automation of a procedure is achieved. The whole calibration time is controlled within 90s equal to the calibration time of a skillful operator, and the calibration precision is even superior to that of manual calibration.
Owner:AQUILLANETWORKTECH

Fundus OCT imaging method utilizing three-dimensional imaging of binocular stereo vision and system thereof

The invention provides a fundus OCT imaging method utilizing three-dimensional imaging of binocular stereo vision and a system thereof with the purpose of solving the problem that three-dimensional correction of phase positions, spatial positions and angles of OCT signals is not precise. The method comprises following steps of: synchronously collecting a binocular stereo vision imaging system and a fundus OCT system; utilizing a self-calibration result of the binocular stereo vision imaging system and acquiring a rotation matrix ROI and a translation vector TOI between an OCT coordinate system and an coordinate system for binocular stereo vision and re-establishing three-dimensional coordinates of bifurcation points of retina surface vessels; acquiring a rotation matrix RIE and a translation vector TIE from the coordinate system for binocular stereo vision to a coordinate system of human eyes; extracting a retina B scanning image; utilizing the rotation matrix ROI and the translation vector TOI in order to achieve conversion of the B scanning image from the OCT coordinate system to the coordinate system for binocular stereo vision; utilizing the rotation matrix RIE and the translation vector TIE in order to realize conversion of the B scanning image from the coordinate system for binocular stereo vision to the coordinate system of human eyes; obtaining a three-dimensional OCT image with uniform spatial distribution by interpolation of the converted B scanning image in the coordinate system of human eyes.
Owner:BEIJING INFORMATION SCI & TECH UNIV

Online offset correction method and device for robot hand-eye calibration

ActiveCN108818536AEasy and Accurate AcquisitionPrecision AdjustmentProgramme-controlled manipulatorProduction lineRobot hand
The invention relates to an online offset correction method and device for robot hand-eye calibration. The online offset correction method comprises the steps that coordinate values of the circle centers of nine circles on a calibration plate in a camera coordinate system and a base coordinate system are obtained; a transformation equation of the circle center of each circle on the calibration plate from the camera coordinate system to the robot base coordinate system is established, through offset coordinates of each circle, the least square method is adopted to calculate a homogeneous transformation matrix of the camera coordinate system relative to the robot base coordinate system; and according to calibrated pose values of the camera coordinate system relative to the base coordinate system, errors of the offset correction calibration results of the nine circles on the calibration plate are analyzed through a vector two-norm formula, and thus the precision of the online offset correction method is evaluated. According to the online offset correction method and device for robot hand-eye calibration, offset in the robot hand-eye calibration process is corrected, flexible, preciseand rapid adjustment on a production line can be achieved, high-repeatability and precise grabbing operation can be achieved, the online offset correction method and device can be applied to operationof an SCARA robot hand-eye device, and the simple, efficient and high-precision effects are achieved.
Owner:武汉库柏特科技有限公司

High-precision motion platform-based multi-camera calibration method

ActiveCN106097300AHigh precision measurementHigh-precision automatic control capabilityImage enhancementImage analysisLinear motionMulti camera
The invention discloses a high-precision motion platform-based multi-camera calibration method. In a whole working region, a calibration plate fixed to a high-precision motion platform through an objective table can make any known linear motion of rotation, translation and the like, and a pose of the calibration plate in a world coordinate system is obtained. The calibration plate moves under the control of the high-precision motion platform to appear in sight of one or more cameras, the cameras shoot images, coordinates of corresponding points in the world coordinate system and an image coordinate system are searched for, and finally parameters of all the cameras are solved once by adopting a global optimization algorithm, so that the shortcoming of low efficiency, relatively large accumulative error, trouble of designing a specific calibration part or the like due to one-by-one calibration of cameras in a multi-camera system in an existing calibration method is overcome, one-time calibration of the whole multi-camera system is realized, the method has greatly important engineering application values, and high-precision calibration and three-dimensional reconstruction are finished. A measurement process is simple, a calibration result is accurate, and the working efficiency is improved.
Owner:XI AN JIAOTONG UNIV

A structured light parameter calibrating apparatus and method based on a front-film-plated plane mirror

The invention discloses a structured light parameter calibrating apparatus and method based on a front-film-plated plane mirror. The method comprises the following steps: a front-film-plated plane mirror and a plane glass target are placed in front of a camera; the camera simultaneously shoots the image of the plane glass target and a mirror image of the plane glass target; a virtual binocular measurement model is established; optimal solutions of a rotation matrix from a front-film-plated plane mirror coordinate system to a camera coordinate system and a translation vector are obtained by a nonlinear optimization method; image vanishing point solving is carried out on optional feature points by the least squares method; white printing paper is placed in front of the front-film-plated plane mirror, and the camera takes the actual light bar image and the mirror image light bar image; and the center point of the light bar image is extracted to calculate the three-dimensional coordinates of matching points to solve an optical plane equation. According to the invention, the light bar quality is improved and the light bar center extraction precision is raised; feature points with the position precision of the micron order are provided to obtain more calibration points; higher calibration precision is realized; and the calibration result is more stable.
Owner:BEIHANG UNIV

Visual 3D taking and placing method and system based on cooperative robot

The invention provides a visual 3D taking and placing method and system based on a cooperative robot. The method comprises the steps that internal and external parameters of a camera of a binocular structured light three-dimensional scanner are calibrated; the hands and eyes of the cooperative robot are calibrated, and a calibration result matrix is obtained; a three-dimensional digital model of to-be-taken-and-placed target objects is collected; the calibrated binocular structured light three-dimensional scanner is adopted to obtain point cloud data of the to-be-taken-and-placed target objects which are stacked in a scattered mode, and the point cloud is segmented to obtain scene point clouds of the multiple to-be-taken-and-placed target objects; the to-be-taken-and-placed target object with the highest grabbing success rate is selected as a grabbing target according to the scene point clouds of the multiple to-be-taken-and-placed target objects; the three-dimensional digital model ofthe grabbing target and scene point pair features are registered, pre-defined taking and placing pose points are registered into a scene, and a registered pose estimation result is obtained and serves as a grabbing pose of the grabbing target; and a preliminary grabbing path track of the cooperative robot is planned. The target object can be accurately recognized, and the grabbing positioning precision is high.
Owner:新拓三维技术(深圳)有限公司

Calibration system of digital quantity input type electric energy meter

The invention provides a calibration system of a digital quantity input type electric energy meter. The problem of calibration of a novel digital quantity input type electric energy meter is solved. The calibration system of the digital quantity input type electric energy meter comprises an analog power source, high-accuracy PT and CT, a high-accuracy digital voltmeter, an A/D sampling module, a protocol generation module, a management module, an analog standard meter, an electric energy meter to be measured, an error counter and a control computer; the control computer controls the analog power source to output an analog voltage and current signal, and one path of the analog signal is measured by the analog standard meter and used for calculating the error of the meter to be measured; after the other path is converted by the high-accuracy PT and CT and processed by the AD sampling module and the protocol generation module, measurement data which conform to IEC61850 standard are generated and transmitted to the meter to be measured by an optical fiber or a twisted-pair, the meter to be measured receives and analyzes a data frame, the electric quantity is calculated, and the pulse of the electric quantity is output and used for calculating the error of the analog standard meter. The invention can calibrate an indoor digital quantity input type multi-functional electric energy meter which conforms to the protocols of DL/T860-9-1/2 and IEC61850-9-1/2LE, and a calibration result can trace to a national standard.
Owner:CHINA ELECTRIC POWER RES INST +1

Calibration device of laser alignment device and method for measuring indication errors of laser alignment device through calibration device

The invention discloses a calibration device of a laser alignment device and a method for measuring indication errors of the laser alignment device through the calibration device. The calibration device comprises two mutually independent rotation shafts capable of rotating for 360 degrees. One of the rotation shafts is used as a reference shaft and the other rotation shaft is capable of moving, pitching and deflecting in the horizontal direction and vertical direction. By setting the rotation angles of the rotation shafts, and adjusting the horizontal and vertical displacement quantity, pitching quantity and deflection quantity of the other rotation shaft, measurement of the displacement quantity in the horizontal and vertical directions, the rotation angle quantity of an inclinometer and indication errors of alignment deviation of a position sensitive sensor of the laser alignment device can be achieved. According to the invention, operation states of the laser alignment device in actual working processes can be precisely simulated; the standard alignment deviation quantity of measurement shafts can be displayed in a real-time and direct manner; calibration results are quite precise; and operability of the measurement process is quite high.
Owner:广东省计量科学研究院(华南国家计量测试中心)
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