461results about How to "Fast calibration" patented technology

The invention provides a joint measurement method based on a laser radar and a binocular visible light camera to obtain accurate and dense three-dimensional information simply and efficiently. The joint measurement method comprises assuming that the laser radar is a camera device with a fixed internal reference; directly projecting three-dimensional point cloud data into a two-dimensional image, calculating rotation and translation relationships between the laser radar device and the binocular camera by using an image processing method and the matching between the two-dimensional images; creatively introducing an idea for obtaining a matrix norm and a matrix trace to solve a rotation matrix; finally fusing laser radar and binocular stereo vision point cloud data. The method not only can obtain an accurate position and attitude information, but also can reconstruct the special texture and feature information of a target surface, which has a high application value for spacecraft dockingand hostile satellite capture in the military field and workpiece measurement and unmanned driving in the civilian field.

The invention relates to a joint calibration method of a 3D lidar and a monocular camera, and belongs to the field of information fusion. The invention aims at improving the calibration efficiency under the requirement of ensuring the joint calibration accuracy of multi-sensor information fusion. Firstly, the monocular camera is calibrated, and then a normal vector of a target calibration plate in a monocular camera coordinate system, the distance from the target calibration plate to the origin in the monocular camera coordinate system, a normal vector of a fitting plane in a 3D lidar coordinate system and the distance from the origin to the fitting plane in the 3D lidar coordinate system are respectively solved at each position. Then, the results of the joint calibration are solved by using the distance correspondence principle. Finally, the result of the joint calibration is taken as the initial value into an optimization objective function to obtain the optimal joint calibration result. The joint calibration method of the invention greatly reduces human participation, reduces random errors caused by complicated man-made operation, simplifies the process of multi-sensor joint calibration and improves the precision of the calibration.

The invention provides a method and a system for automatically calibrating an electrical instrument. The system comprises a PC, an automatic calibration device controlled by the PC and an instrument hanging table for fixing the instrument to be calibrated. The PC sets a calibration proposal, controls the calibration device to calibrate calibrated instruments synchronously, and controls the calibration device to automatically retest the amplitude, phase, power, frequency and electrical error of the calibrated instrument, automatically store test data and generate test report after the calibration is finished. The method and the system solve the problem of the prior art of low instrument calibration precision and complex calibration process, realize automatic calibration and retest of the high-precision electrical instrument, ensure calibration precision and improve production efficiency.

The invention discloses a robot hand-eye calibration method based on laser range finding. According to the method, by calculating the coordinates of laser spots under a laser range finder coordinate system, the coordinates of the laser spots under a robot coordinate system are calculated by means of the mapping relation between the laser range finder coordinate system and the robot coordinate system; by capturing pictures of the laser spots on a calibration board through a camera, the coordinates of the laser spots under a pixel coordinate system are calculated, and therefore the mapping relation between the pixel coordinate system and the robot coordinate system is calculated; the mapping relation between a camera coordinate system and the pixel coordinate system is obtained by means of parameters of the camera; and then the mapping relation between the camera coordinate system and the robot coordinate system is calculated according to the spatial switching relation. The method is carried out by emitting the laser spots to the surface of an object through a laser range finder, coordinate information of measurement points is obtained without the need of making contact with the object, in this way, operating errors are reduced, operation is easier, precision is high, manual participation is not needed in a calibration process, and automation and intellectualization are achieved.

The invention discloses a calibration method and device used for a laser processing system. The calibration method includes the steps that firstly, a lens in a galvanometer is controlled to be adjusted according to a calibration picture which is edited in advance, a laser device is driven, a laser beam generated by the laser device is made to penetrate through the galvanometer, and the calibration picture is etched on marking paper which is placed on a processing platform in advance; secondly, an image, photographed by a camera, of the processing platform is obtained, and the image includes the calibration picture; thirdly, distortion correction is conducted according to the image and the calibration picture etched on the marking paper, and the corresponding relation between an image coordinate system and a galvanometer coordinate system is obtained. According to the calibration method and device used for the laser processing system, distortion correction is achieved through the calibration picture on the marking paper, a target does not need to be used, cost is saved under the premise that precision is ensured, and the calibration operation is simplified.

An interior rearview mirror system for a vehicle includes an interior rearview mirror assembly, a casing having a reflective element, a compass sensor and a control. The compass sensor is disposed within the mirror casing and has a first magnetoresponsive sensing element and a second magnetoresponsive sensing element. The control receives a first signal indicative of a magnetic field sensed by the first magnetoresponsive sensing element and a second signal indicative of a magnetic field sensed by the second magnetoresponsive sensing element. The control determines that the casing is adjusted by an occupant of the vehicle in response to a change in the first and second signals being indicative of an abrupt movement of the casing about the mounting structure by an occupant of the vehicle. The control is operable to enter a rapid compensating mode to compensate for the mirror adjustment.

The invention provides a table recognition method and system, belonging to the technical field of table recognition, which utilizes nonlinear contrast enhancement based on weighted RC threshold iteration and Gaussian Laplacian LoG operator to carry out binarization processing on table images conforming to the format, and utilizes tilt correction algorithm based on perspective change to carry out tilt correction; uses an image morphological processing method to extract table box lines, segmentation of cells, to obtain the smallest cell; establishes the character database of the smallest cell, carries on the neural network training, establishes the form recognition model, carries on the recognition to the form. The invention has the advantages of simple calculation, fast speed, accurate identification of table images with weak contrast, uneven light and dark distribution of images and blurred background. The speed and precision of recognition are improved by establishing special high-frequency characters, training special neural network and template matching. At the same time, the customized neural network is simple in structure and reduces the time and workload of training and tuning.

The invention discloses an automatic clock oscillator calibration method and an automatic clock oscillator calibration circuit adopted for implementation of the method. The automatic clock oscillator calibration method comprises the following steps of: generating a specific period T through counting of an external precision reference clock, counting clock signals to be calibrated during the period T, comparing an obtained count value with a standard count value of the clock signals to be calibrated, carrying out rough adjustment by increasing or decreasing a control word with dichotomy according to the comparison results, realizing that a frequency of the clock signals output by a clock oscillator to be calibrated is within the acceptable error limit of a frequency corresponding to the standard value, then carrying out fine adjustment around a control word which is obtained by rough adjustment and finding a control word which can minimize the frequency error. The invention can be used for rapidly calibrating the clock oscillator, thereby greatly improving calibration speed of the clock oscillator and guaranteeing precision of the calibration.

The invention discloses a satellite orientation based azimuth calibration method and device. According to the method, true north azimuths of two satellite antenna represented base lines are calibrated according to a high-precision relative positioning principle based on carrier phase ambiguity-resolving; the azimuths of the base lines are derived with angle measuring instruments such as a theodolite or a total station; the true north information of each azimuth to be measured is measured. According to the satellite orientation based azimuth calibration method and device, high-precision satellite orientation is used as an azimuth reference, and the theodolite is used to derive the true north azimuth of the azimuth reference for azimuth calibration. The satellite orientation based azimuth calibration method and device has the advantages that the ways of using traditional fixing marker post and the like are replaced by the use of a movably erectable GNSS (global navigation satellite system) antenna, no satellite differential station is required, azimuth calibration flexibility is greatly improved, and the azimuth calibration range is greatly widened.

The invention discloses a camera external parameter calibration method of a multi-camera system for solving the problems that a three-dimensional precise calibration object is difficult to manufacture, the efficiency of a multi-camera external parameter calibration process is low, and that accumulative errors are generated in the existing method. The method comprises the following steps: performing fitting to obtain quadratic curve matrixes of shooting ball projections of cameras; solving inhomogeneous coordinates of three spherical centers in a camera coordinate system; establishing a world coordinate system in which the three spherical centers are located on the same plane through the plane where the three spherical centers are located and the positions of the spherical centers; solving external parameters of a plurality of cameras in the world coordinate system in which the three spherical centers are located on the same plane, and accomplishing the external parameter calibration of the cameras in the multi-camera system, wherein the two coordinate systems are overlapped. By adoption of the camera external parameter calibration method disclosed by the invention, the external parameters of the plurality of cameras in the same world coordinate system are calculated quickly, conveniently and accurately without requiring more conversion, no accumulative error is generated, and the camera external parameter calibration precision is high. The camera external parameter calibration method is applied to the fields of image measurement, three-dimensional reconstruction, unmanned aerial vehicle navigation, etc.

The invention relates to a method for calibrating the direction of a three-probe start sensor, which can effectively solve the problem of requirements on the calibrating accuracy and measuring accuracy of the direction of the three-probe start sensor. The technical scheme for solving the problem comprises the following steps of: combining three cubic prisms pairwise; linking four theodolites; aligning the every two combined cubic prisms by using the four theodolites respectively and recording data; performing mutual aiming; recording mutual aiming data; and resolving a rotation matrix between two reference cubic prisms. The method is easy and convenient to operate, has high calibration speed and high accuracy, does not need to focus for measuring and can effectively solve the problem of requirements on the calibrating accuracy and measuring accuracy of the direction of the three-probe start sensor.

The invention discloses a projector array splicing display method. The method comprises the following steps that 1), a transformation matrix is calculated, point coordinates of standard black and white chessboard features are collected through a camera, the transformation matrix from coordinate systems of projected images to coordinate systems of screen images is calculated, and a pre-correction matrix is calculated; 2), edges of the projected images are fused, sampling is carried out on overlap areas of every two adjacent projected images according to cosine functions, fusion coefficients of the images of the overlap areas are obtained, and pixel RGB values of the overlap areas are multiplied by the corresponding fusion coefficients to obtain the effect of seamless splicing of every two adjacent protected images; 3), geometric correction is carried out, the pre-correction matrix is used for carrying out perspective transformation on the images after the edges are fused and processed, and the final projected images are the images after geometric correction; 4), a plurality of the projected images are spliced, according to the methods in steps from one to three, every two adjacent projected images are spliced through a projector array according to the sequences from top to bottom and from left to right, and finally display of the spliced image of the whole projector array is obtained.

The invention relates to the technical field of computer vision detection, in particular to a calibrating method for a centralized vision system of a soccer robot; the calibrating method comprises the following steps of: using a system site as a calibrating template, using certain mark points on the site as calibrating reference points, and obtaining pixel coordinates and world coordinates of the calibrating reference points; establishing an imaging model of the camera according to the characteristics of the centralized vision system of the soccer robot, respectively obtaining the internal and external parameters of the camera by using the pixel coordinates and world coordinates of the calibrating reference points and optimizing the related parameters; and by using the internal and external parameters of the camera, establishing pixel coordinates of an original site image to conversion modules of the world coordinates to which planes corresponds, wherein target bodies with different heights are arranged in the planes. The calibrating method belongs to the field of computer vision detection and can be used for calibrating the camera with a vision detection system similar to the centralized vision system of the soccer robot; and the calibrating method is simple, easy to use and higher in accuracy without needing other auxiliary calibrating devices.

The invention discloses an RF (radio frequency) receiving front end with diversified gaining modes and capable of automatic tuning. The RF receiving front end comprises a low-noise amplifier, a frequency mixer, a complex filter and a time constant correcting circuit. The input end of the low-noise amplifier is connected with an input signal, and the output end adopts NC (numerical control) resistance as load to correct gains; the differential input ends of the I-path frequency mixer and the Q-path frequency mixer are respectively connected to the output end of the low-noise amplifier, and thedifferential output ends are respectively connected to the differential input end of the complex filter; the complex filter which adopts a multi-stage cascaded structure realizes the diversified gaining modes by the NC resistance, and meanwhile a time constant can realize tuning by controlling a capacitance array; and the output end of the time constant correcting circuit is connected with the correcting control word input end of the complex filter. By combining the current-mode low-noise amplifier, the passive frequency mixer and the active RC complex filter with each other, the RF receivingfront end has the advantages of low noise, high linearity, low power consumption, low cost and the like.

The invention discloses an error correction method of a flying probe tester. The method comprises the steps that the center of a cross target of a camera image is pointed to the center o of one test point of a PCB board to be calibrated; a probe is controlled to detect the PCB board to acquire a probe test point t; the probe test point t is taken as an initial point, and the probe is controlled to search an edge point a1 and an edge point a2 on both sides along X or Y direction; according to two detected edge points in X or Y direction, a center point a3 in X or Y direction is searched; the center point in X or Y direction is searched in the same manner, and the center point is the center o of the test point of the PCB board to be calibrated; the deviation between the probe initial point t and the center o of the test point is the actual offset of the probe to the camera center; and after a control system compensates the actual offset, a test is carried out. According to the error correction method, the actual offset of the probe to the camera center can be determined before the flying probe tester is used, and the test accuracy of the flying probe tester is ensured.

The invention discloses an online coal property detecting and analyzing method, which is based on regression analysis, utilizes a spectral line intensity group of calibration coal samples and builds the following two calibration curves of all elements through the least square method: C equals to aI plus e, and C equals to AI plus summation of *BC plus Dg(C) plus E. In the detection of samples of unknown coal flows to be detected, first-time computed mass concentration of each element is computed by characteristic spectral line intensity of laser-induced plasma of each element, and the mass concentration of an element to be detected is calculated according to the calibration curves; alternatively, calibration of carbon element is implemented for two times, second-time computed mass concentration of each element is calculated, and then the mass concentration of the element to be detected is calculated according to the calibration curves. The online coal property detecting and analyzing method utilizes all the information of LIBS spectrum, avoids errors caused by complex calibrating methods, reduces the influence of maternal effect, has quick calibrating speed and high precision, can realize online coal full-element analysis, and can provide the real-time data of coal elements for users.

The invention discloses a three-dimensional calibration device for a curve flexible touch sensor array, which comprises a three-dimensional guide rail robot, a three-dimensional force loading mechanism, an array platform and a control part electrically connected with the array platform, wherein the three-dimensional guide rail robot comprises an X axis guide rail, a Y axis guide rail and a Z axis guide rail, each of which is provided with a grating ruler having a position detection function; the three-dimensional force loading mechanism is arranged at the lower end of the Z axis guide rail through an installing flange of a parallel mechanism; the three-dimensional force loading mechanism comprises the parallel mechanism and a three-dimensional force detecting part; and the three-dimensional force detecting part is arranged at the operation tail end of the parallel mechanism. The device is used for realizing the accurate positioning by driving the three-dimensional guide rail robot to drive the three-dimensional force loading mechanism to perform spatial positioning and matching with the closed loop position control of the grating ruler. The parallel mechanism is used for adjusting the posture of a three-dimensional force loading head. When three-dimensional force detected by a standard three-dimensional touch sensor reaches a preset value, a measuring value and a corresponding matrix position coordinate of a sensor sampling circuit are outputted.

The invention discloses an ordered binary decision diagram modeling method for distribution network fault recovery. The method includes a first step of carrying out partition on a power distribution network, and using an on-off state as a decision variable, a second step of forming an adjacent matrix of the power distribution network according to a forming method of the adjacent matrix of an undirected graph, a third step of forming a reachable matrix of the power distribution network, a fourth step of forming boolean functions of each restriction of fault recovery, a fifth step of combining to generate a final binary decision diagram, and obtaining a contractive solution space, a sixth step of carrying out load flow calculation on feasible solutions one by one in the solution space after contraction, and carrying out safety verification, and a seventh step of obtaining an optimal recovery scheme according to priority levels of optimized objective functions. The modeling method has the advantages of effectively reducing the solution complexity of fault recovery problems, overcoming the defect that a traditional artificial intelligence algorithm is prone to premature convergence in local optimal solution, and improves understanding reliability and the like.

An improvement to a flat bed knitting machine comprises a wheel positioned on the carrier of the flat bed knitting machine. The wheel turns as yarn passes thereover for knitting, thus allowing the wheel to measure the amount of yarn used. A series of magnets positioned on a bar beneath the needle bed send signals to a sensor attached to the carriage of the knitting machine as the sensor passes thereover. These signals instruct a logic circuit contained within a logic circuit control box to accept input from the wheel. The magnets are spaced apart by the distance of a known number of needles. Thus, the amount of yarn used can be divided by a known number of needles to arrive at a stitch size to help in the calibration of the flat bed knitting machine.

The invention discloses a calibration method and device for an angle encoder. The method comprises the steps that a stepping motor is controlled to rotate by at least 360 degrees step by step, the angle data of the stepping motor after the stepping motor rotates by the appointed angle are collected step by step through a high-precision encoder and the angle encoder to be calibrated so as to obtain a plurality of angle data sets, error factors are initialized, a plurality of error factor sets are generated and serve as particles, and an optimal error factor set is selected as a calibration result to be output according to the particle swarm optimization and the angle data set. The device comprises a host, a stepping motor controller and a base support. The base support is provided with the stepping motor and the high-precision encoder. An output shaft of the stepping motor is respectively connected with the angle encoder and the high-precision encoder. The high-precision encoder and the angle encoder are respectively connected with the host. The stepping motor controller is connected with the stepping motor. The device has the advantages of being high in calibration precision, low in calibration cost, small in needed calibration data size and high in calibration speed.

The invention discloses a system and a method of quick adjustment of a liquid crystal display television. The system and the method of quick adjustment of the liquid crystal display television comprise a liquid crystal display television to be adjusted, a color analysis meter and an optesthesia color correction control device. The optesthesia color correction control device sends instructions to a display control main board of the liquid crystal display television to be adjusted to ensure that the liquid crystal display television to be adjusted displays a specific testing image; the color analysis meter acquires actual color data of the testing image displayed by the liquid crystal display television to be adjusted and sends the actual color data to the optesthesia color correction control device; the optesthesia color correction control device compares the received actual color data with arranged goal Gamma and color temperature, and therefore acquires an adjustment value, and sends the adjustment value to the display control main board of the liquid crystal display television to be adjusted to conduct corresponding white balance adjustment until acquired color adjustment data is most close to the arranged goal Gamma and the color temperature, and conducts fitting on most similar color adjustment data and a goal optesthesia curve, and accordingly acquire adjusted Gamma curve.

The invention discloses a target method for quickly calibrating intrinsic parameters of a vidicon and belongs to the field of computer vision measurement. The target method comprises the steps of quickly calibrating intrinsic parameters of the vidicon by means of a target in a shape of regular triangles with inscribed circles; extracting image coordinates of centers of the inscribed circles, and establishing a homography matrix equation according to homography of a target plane and an image plane; extracting shape information of the regular triangles and the inscribed circles, calculating image coordinates of vertexes and points of tangency of the regular triangles to obtain a regular triangle vertical line equation, acquiring end points of parallel lines according to orthogonal parallel segments formed by corresponding sides and vertical lines of the four regular triangles, and establishing an end point equation; performing solving on intrinsic parameters of the vidicon. By means of the target method, the calibration process is simple and convenient, a matrix of intrinsic parameters of the vidicon can be obtained only by shooting a target image, the calibration speed is high, and quick calibration in large visual fields and under complex environments can be achieved.

The invention discloses a high speed aberration correction method based on machine learning. The incident parallel beam passes through the spatial light modulator that does not load the wavefront phase distribution to obtain the ideal focused spot. A series of wavefront phase distributions are obtained using the Zenike polynomial processing, and each wavefront phase distribution is loaded into the spatial light modulator to obtain a distorted focused spot. The light intensity distribution of each distorted focused spot and the respective Zenike coefficients under the incident wave wavefront distribution are input to the machine learning training to obtain the correction model. The intensity distribution of the distorted focused spot pattern of the scattering medium to be measured is input to the calibration model to obtain the values of the respective Zenike coefficients, and by taking the negative value calculation, the corrected phase distribution is obtained and loaded into the spatial light modulator to achieve aberration correction. The method can realize the high speed optical aberration correction of the optical path, the correction speed is fast and the accuracy is high, and the problem that the traditional adaptive optical algorithm is slow is solved.

The invention relates to an electric quantity data storage method for an electric energy meter. The method is characterized by comparing a check code obtained through calculation with an initial check code pre-stored in a nonvolatile memory when the electric energy meter is energized; and when the electric energy meter is not energized, verifying and storing the current electric quantity data, and performing accumulative updating for the electric quantity data during the operation process of the electric energy meter, and also verifying the electric quantity data during every process for storing the updated electric quantity data, thus guaranteeing the accuracy of the electric quantity data. Besides, the electric quantity data storage method also utilizes the nonvolatile memory to store and back up the electric quantity data at regular intervals, thus preventing loss of data and being more reliable in storage.

The invention discloses a resistance capacitance (RC) constant measuring method based on frequency measurement. Based on the output frequency measurement and the RC constant design, and the relationship between an output frequency of an oscillator and an RC constant in the frequency oscillator, the RC constant measurement based on the frequency measurement and the application of RC constant measurement in correction of a frequency oscillating circuit are realized. A measurement modular circuit effectively realizes the frequency oscillating circuit according to the fact that the RC constant setting and the output frequency have a definite inverse proportional relationship, and provides preconditions for the digital circuit measurement and correction adjustment. A digital circuit is convenient and flexible to measure an oscillating frequency and the RC constant; and a correction speed is greatly improved by a binary search algorithm.

The invention relates to an oscilloscope with an improved front-end circuit. The oscilloscope includes the front-end circuit and a control processing module. The front-end circuit includes an input-stage buffer and addition circuit, a gain selectable amplifying module, an A / D conversion circuit and a D / A conversion circuit. The input-stage buffer and addition circuit is connected to the control processing module via the gain selectable amplifying module and the A / D conversion circuit sequentially. A gain selection output end of the control processing module is connected with an input end of the gain selectable amplifying module. The other end of the control processing module provides front-end-circuit offset signals via the D / A conversion module. The offset signals are output to the input-stage buffer and addition circuit. The oscilloscope improves a minimum resolution input by the ADC and reduces demands on the gain of a simulation front end and adopts switching of amplifiers of a plurality of gains in combination with digital gains so that cost is saved and a signal-to-noise ratio of input ADC signals is improved.

The invention provides a digital signal processor (DSP)-based intelligent gas sensor checking instrument for mines, comprising a microcontroller unit, a signal conditioning unit, a communication interface unit, a keyboard display unit, a touch control unit and a gas circuit system; and in the invention, the communication connection is carried out on the units and modules of the checking instrument. In the invention, the existing checking instrument structure is improved, and the central processing unit (CPU) technology, the electronic technology and the control technology are taken as main technologies, thereby solving the problems of low speed, low accuracy and high labor intensity of the existing checking instrument and providing services for underground safety production of coal mines.

The invention discloses a method and a device for burning set-top box storage chips. A set-top box is used as a master set-top box, burning data in the master set-top box is written into to-be-burnt target storage chips, parallel burning of multiple target storage chips of different technical platforms can be performed by the master set-top box, the burnt storage chips can be placed into target set-top boxes which can be then used as master set-top boxes for burning rest target storage chips, and accordingly burning efficiency and compatibility to various chip platform application are improved. Burning operation can be controlled by simple operation on a remote controller, and the method is simple to operate and easy to master and implement by operators. By CRC (cyclic redundancy check) of data in the master set-top box before burning and data in the target storage chips after burning and comparing CRC codes of the two, burning data reliability and completeness are improved.

The invention relates to a calibration system of a wind direction sensor, comprising a base. The calibration system is characterized in that the base is provided with a rotating disc, a photoelectric sensor, a control circuit and a driving motor; the edge of the rotating disc is provided with a plurality of through holes at equal intervals; the central position of the rotating disc is provided with a fixed hole; the transmitting end and receiving end of the photoelectric sensor are respectively arranged at the two sides of the rotating disc; and the control circuit is electrically connected with the photoelectric sensor, the driving motor and the wind direction sensor respectively; and the number of the through holes is 36. The calibration method of the calibration system provided by the invention comprises the following steps: a. firstly, judging whether signals are input or not; b. judging whether pulse signals are input or not; and c. reading a wind direction value and sending the wind direction value to an upper personal computer (PC). According to the invention, as the driving motor and the photoelectric sensor are arranged, automatic calibration of the wind direction sensor is realized, and the speed and accuracy of calibration are increased; and for the calibration method provided by the invention, data acquisition is completed automatically, so that the original fussy mode of manual reading is changed.

The invention discloses a calibration method for multi-projection splicing. The method is characterized by comprising the steps as follows: two horizontal calibration lines and two perpendicular calibration lines are generated by a system and added to split pictures of a source picture; at the same time, the system generates an initial rectangular frame picture for each split picture of the source picture; four peaks of each initial rectangular frame picture are adjusted by limiting one direction of the horizontal position direction and the perpendicular position direction, so that an initial calibration window corresponding to the initial rectangular frame picture becomes a final rectangular frame picture; horizontally spicing is performed, and projection split pictures are moved perpendicularly and horizontally, so that horizontal calibration lines of a projection are aligned to each other vertically and respectively, and perpendicular calibration lines of splicing sides of the projection split pictures are overlapped; and when vertically splicing is performed, the projection split pictures are moved horizontally and perpendicularly, so that perpendicular calibration lines of the projection are aligned to each other horizontally and respectively, and at the same time, horizontal calibration lines of splicing sides of the projection split pictures are overlapped. Compared with the prior art, the method has the advantage that the calibration process and the calibration speed are simplified.