846results about How to "Improve calibration accuracy" patented technology

The embodiment of the invention provides a mining area vehicle path planning method and device based on a digital twin map, and belongs to the technical field of vehicle path planning, and the method comprises the steps: obtaining map data and physical scene data of a mining area; creating a dynamic twin map of the mining area based on the map data and the physical scene data; obstacle information is identified and marked based on the dynamic twin map, and obstacles comprise natural obstacles and artificial obstacles; and importing related data of the vehicle into the dynamic twin map, and carrying out obstacle avoidance path planning on the vehicle based on the marked obstacle information to obtain an optimal obstacle avoidance path. According to the scheme, the running efficiency of mining area vehicles can be improved, and collision and obstacle detouring time is shortened.

The invention relates to the technical field of data processing, and discloses a salinity drift correction method and system for buoy observation data. The method comprises the steps that historical buoy observation data and current environment parameters are collected and preprocessed, and a multi-source heterogeneous data set is obtained; performing multi-dimensional environmental factor analysis on the multi-source heterogeneous data set to obtain a salinity influence factor weight; drifting detection and quantification are carried out on the buoy salinity data through the salinity influence factor weight, and an accumulated deviation integral value is obtained; performing multi-scale correction calculation on the accumulated deviation integral value to obtain preliminary correction data; performing dynamic space-time weight optimization on the preliminary correction data to obtain optimized correction data; and performing real-time performance evaluation and automatic threshold adjustment on the optimized correction data to obtain target correction data and a parameter updating strategy. According to the invention, the accuracy of salinity drift correction for buoy observation data is improved.

According to the power control method and system based on energy storage unit adjustment priority evaluation, an energy storage unit calibrates the charge state, the battery capacity and the health state of the energy storage unit and feeds back the charge state, the battery capacity and the health state to a battery management system; the battery management system verifies a built-in battery state estimation model of the battery management system by using the calibrated charge state and health state; based on the calibrated charge state and the battery capacity, calibrating the energy state range; calibrating the voltage standard deviation coefficient, the voltage range and the temperature range based on the measurement precision of the sensor; taking the weighted sum of each evaluation index score after calibration of the energy storage unit as a comprehensive evaluation score; determining the adjustment priority of the energy storage unit allowed to be adjusted by using the comprehensive evaluation score and the charge-discharge cycle times of the energy storage unit allowed to be adjusted; and selecting the adjustment-allowed energy storage unit with the highest adjustment priority as an execution unit for responding to the scheduling target power instruction, and ensuring the safe and stable operation of the energy storage system at the same time.

The invention discloses a reference camera device and system based on a motion capture system, and the device comprises a camera connection module which is used for building the signal connection between a reference camera and the motion capture system, and outputting a successful connection result of the reference camera after the successful connection; the synchronous calibration module is used for synchronously calibrating the reference camera and the motion capture camera and outputting a calibration success result after calibration succeeds; the projection module is used for projecting the to-be-measured object in the three-dimensional space to the reference camera for two-dimensional display to obtain virtual scene information; the virtual-real superposition module is used for superposing the virtual scene information and an image actually shot by the reference camera to judge whether the motion capture effect is correct or not, and if the motion capture effect is correct, outputting a motion capture effect correct result; and the data recording module is used for judging whether a recording button in the motion capture system is clicked or not, and if the recording button is clicked, recording to obtain recorded video data information and caching the recorded video data information. The method has the effect of improving the accuracy of virtual and real scene comparison during shooting of the reference camera based on the motion capture system.

The invention relates to the technical field of instrument calibration, and particularly discloses a gas detection instrument prediction calibration system and method. The analysis module is used for determining a detection method of the zero drift phenomenon of the electrochemical gas sensor to be calibrated based on the use environment type; the calibration module is used for determining real-time calibration or periodic calibration of the electrochemical gas sensor in response to the occurrence of the zero drift phenomenon and the abnormal opening state of the electrochemical gas sensor; the evaluation module is used for determining the long-term zero point stability degree or the real-time signal fluctuation degree to evaluate the calibration precision according to the calibration method; the adjusting module is used for determining whether to update the environment compensation coefficient and adjust the calibration interval duration for the next calibration according to the evaluation result of the evaluation module; according to the invention, the accuracy of analyzing the use environment of the electrochemical gas sensor is improved, so that the accuracy of analyzing the zero drift phenomenon is improved, and accurate calibration is realized.

The invention relates to the technical field of laser calibration, in particular to a laser optical axis calibration device and method, and the device comprises an optical axis offset detection module, a calibration parameter calculation module, a dynamic adjustment implementation module and a calibration effect evaluation module. According to the invention, the response speed and precision are enhanced by monitoring the output of the laser emitter in real time, evaluating the instant deviation of the optical axis and dynamically calibrating the optical axis, the deviation trend of the optical axis is predicted by using a data analysis technology, the future deviation path is effectively controlled, and non-critical calibration is reduced, so that the long-term performance and stability of equipment are improved; dynamic adjustment measures are adopted, the positions of an angle adjuster and an optical element are finely adjusted, so that high calibration precision is ensured, energy loss and equipment abrasion are reduced, calibration effect evaluation of a vibration sensor provides immediate feedback for operation, transparency of the calibration process is improved, an operator can make a more accurate decision based on detailed data, and the operation efficiency is improved. Therefore, the reliability and the operation efficiency of the calibration task are enhanced.

The invention discloses a wafer calibration method and device based on machine vision, equipment and a medium. The method comprises the following steps: determining a tray rotation center position according to a tray image obtained by motor rotation; wherein a reference circle scale line of which the radius is greater than that of a target wafer is engraved on the tray; placing a target wafer in the reference circle scale line on the tray, and performing image acquisition on the tray to obtain a target image; determining the circle center position of the wafer according to the distance between the reference circle scale line and the target wafer based on the target image; based on the target image, determining a wafer deviation angle according to the reference circle scale line, the wafer center position and the wafer gap identification information; and according to the rotation center position of the tray, the circle center position of the wafer and the deviation angle of the wafer, carrying out position calibration on the test point on the target wafer. According to the invention, the wafer calibration efficiency is improved, and the operation of repeatedly taking the wafer from the wafer carrier to the wafer calibrator and then to the process position during wafer calibration is avoided.

The invention belongs to the field of industrial robot error calibration, and particularly relates to a vision-based industrial mechanical arm zero deviation calibration method, which comprises the following steps of: 1) fixing a vision camera at the tail end of a mechanical arm, and fixing a marker in a working area range of the mechanical arm; (2) the mechanical arm is manually operated, the spatial position of a camera fixed to the tail end of the mechanical arm is changed, all corresponding pose data are recorded, the mechanical arm is moved multiple times, and multiple sets of calibration data are collected; (3) the pose change of the marker when the spatial position of the camera fixed to the tail end of the mechanical arm is changed is obtained, and a calibration equation based on zero deviation and hand-eye pose deviation is constructed; and (4) multiple sets of collected calibration data are substituted into the calibration equation, and after optimization is conducted, the zero deviation of the mechanical arm and a hand-eye pose transformation matrix are obtained and compensated to configuration of a mechanical arm controller. According to the method, the zero deviation calibration of the mechanical arm and the calibration of the hand-eye pose transformation between the mechanical arm and the visual equipment can be completed at the same time only through one calibration process.

The invention provides a high-resolution positioning method for noise source imaging. The high-resolution positioning method comprises the following steps: designing a sensor array layout and selecting sensors; a multi-channel acquisition synchronous acquisition sensor and records signals to obtain acquisition data; performing signal processing on the acquired data by using adaptive filtering, machine learning calibration, time-frequency analysis and intelligent beam forming technologies to obtain standard data; based on the standard data, performing high-resolution direction estimation by using an optimized multi-signal classification algorithm, and removing a sidelobe effect by using an optimized CLEAN algorithm to complete processing of the standard data; and based on the processed standard data, reconstructing a spatial distribution image of the noise source by using an inversion technology, and dynamically adjusting the resolution of the reconstructed spatial distribution image by using an adaptive algorithm to realize high-resolution positioning of noise source imaging. According to the invention, high-resolution positioning can be realized, the reliability and precision of noise detection are improved, and noise control and management are more effective.

The invention provides a live pig facility breeding hog house ammonia concentration detection system based on a neural network, and the system comprises a hog house environment parameter collection module and a hog house ammonia concentration detection module which are connected in sequence. Wherein the hog house environment parameter acquisition module is used for acquiring ammonia gas information, wind speed information, temperature information and humidity information in a hog house; and the pig house ammonia gas correction fusion sub-module is used for correcting the predicted ammonia gas concentration based on the predicted wind speed, the predicted humidity and the predicted temperature. The method analyzes the influence of pig house ammonia gas on pig health, considers the coupling effect of multiple environment parameters of the pig house, provides a temperature, humidity and wind speed correction fusion method of the pig house ammonia gas concentration, and aims to improve the detection precision of the pig house ammonia gas concentration of pig facility breeding.

The invention provides a camera calibration method, a calibration system and a storage medium. The camera calibration method comprises the following steps: adjusting an image acquisition state in real time based on illumination intensity and a reference object to obtain a plurality of reference object images so as to obtain a distortion coefficient of a target camera, and performing distortion removal correction on the reference object images according to the distortion coefficient to obtain an initial calibration parameter; further calculating a first projection error according to the initial calibration parameter, and taking the initial calibration parameter as a target calibration parameter when the first projection error is within a preset error range; and otherwise, obtaining the target calibration parameter based on the cloud calibration data and the initial calibration parameter. According to the method, high-quality reference object images can be obtained under different illumination conditions, the calibration accuracy can be objectively evaluated through the first projection error, cloud calibration data is adopted for optimization, and the accuracy of calibration parameters is improved; meanwhile, the whole process is automatically carried out, and the calibration efficiency and precision are improved.

The invention discloses a calibration method for a wind meter, and the method comprises the steps: obtaining the collected environment data in a wind field environment, and the wind power data, outputted by the wind meter, of the wind field environment; comparing the wind power data with preset standard wind power data, and determining an initial compensation coefficient of the wind meter; determining an influence factor corresponding to the environmental data, and determining an environmental compensation parameter according to the influence factor; wherein the influence factor is used for representing a parameter of the influence degree of the environmental data on the output of the wind meter; and obtaining a target compensation coefficient based on the environment compensation coefficient and the initial compensation coefficient, and calibrating the wind meter according to the target compensation coefficient. The problem that the calibration accuracy is low in the calibration process of the wind meter in the prior art is solved.

The invention discloses a method and equipment for pre-printing calibration of different spray heads and a storage medium. The method comprises the following steps: S1, obtaining a printer spray head distance and a color register calibration pattern; s2, setting resolutions matched with different nozzles in the calibration pattern; s3, the calibration pattern is imported into a printer, and the calibration pattern is printed; s4, performing visual identification on the printed calibration pattern, and respectively identifying a frame and a color block of the calibration pattern; s5, after the recognition result is obtained, the nozzle is calibrated through coarse adjustment scales on the right side and the lower portion of the calibration pattern; s6, after calibration, the calibration pattern is printed again; s7, the step S3 is repeated until the color blocks of the calibration pattern are completely overlapped in the square frame, the problems that in the prior art, the calibration difficulty is large, and lines and color spraying cannot be calibrated at the same time are solved, through the specific calibration pattern and visual recognition equipment, the nozzle distance and the color register condition can be accurately analyzed, the accurate offset can be obtained, and the purpose of fine calibration is achieved.

The invention discloses a wave in-situ calibration method based on a GNSS buoy, and belongs to the field of wave in-situ calibration, and the method comprises the following steps: obtaining buoy deviation data based on the position and attitude data of the GNSS buoy under different sea conditions; constructing a deviation compensation model and a deviation sliding model based on the buoy deviation data; a deviation compensation result is obtained based on the deviation compensation model and the deviation sliding model, and the deviation compensation result comprises first deviation compensation and second deviation compensation; and fusing the deviation compensation result with the GNSS positioning data to obtain a wave parameter estimation result.

The invention discloses an appearance detection multi-camera image splicing method and system and a related device, which are used for improving the overall quality and accuracy of image splicing in a multi-camera vision field non-overlapping scene. The method comprises the following steps: respectively calibrating a main camera and an auxiliary camera through a calibration board in combination with a weighted error minimization model; determining a pixel plane transformation matrix from the auxiliary camera to the main camera; transforming an initial image shot by the auxiliary camera to a pixel plane of the main camera according to the pixel plane transformation matrix; projecting the vision fields of all the cameras into a world coordinate system, and judging whether the projection positions of the vision fields are overlapped or not; if yes, feature points are extracted from the to-be-spliced image, the feature points are screened through a distance threshold value and a quality threshold value, and a feature point pair set is obtained; and calculating a perspective transformation matrix between the to-be-spliced images based on the feature point pair set, and splicing and fusing the to-be-spliced images according to the perspective transformation matrix and the vision field projection position.

The invention provides a calibration method and device of motion capture equipment, equipment and a medium, the motion capture equipment is worn on a limb of a human body, the method is applied to head-mounted display equipment, the head-mounted display equipment comprises a camera, and the method comprises the following steps: collecting an image of the motion capture equipment through the camera; according to the motion capture equipment image, determining target attitude information of an equipment coordinate system relative to a world coordinate system; and calibrating the motion capture equipment according to the target attitude information. The motion capture equipment is calibrated by using the image of the motion capture equipment, so that the calibration difficulty of the motion capture equipment can be effectively reduced, the calibration time can be shortened, the calibration error can be reduced, and the calibration precision of the motion capture equipment can be improved.

The invention belongs to the field of automatic measurement and lineation of complex castings, and discloses a double-robot high-precision calibration and online optimization method, which comprises the following steps of: based on hand-eye calibration, four-point calibration and the like, respectively calibrating each part of a casting-measurement system-lineation system during system deployment to obtain high-precision system parameter initial values; on the basis of online collection of calibration data in the measurement-analysis-lineation process of a visual tracking system, online optimization of multi-robot system parameters is achieved, optimized robot paths are fed back on the basis of a data control center, and high-precision stable operation of robot lineation is guaranteed.

The invention belongs to the technical field of industrial automation, and discloses an actuator calibration equipment mechanism which comprises a working panel, a main support is fixedly installed at the right end of the top of the working panel, a calibration assembly is movably installed on the front face of the upper portion of the main support, and a downward pressing air cylinder is fixedly installed at the top of the main support. The output end of the downward pressing air cylinder is connected with a calibration assembly, and a marking assembly is installed at the bottom end of the calibration assembly. Compared with a traditional manual calibration mode, the automatic actuator calibration system based on angle calibration has the advantages that the calibration efficiency is remarkably improved, the calibration accuracy is enhanced, the production flexibility and adaptability are improved, the calibration efficiency, accuracy, flexibility and safety are improved, and the automatic actuator calibration system based on angle calibration is suitable for popularization and application. And quality control and management are optimized, remarkable beneficial effects are brought to industrial automatic production, and the method is an important technical means for promoting industrial automatic upgrading.

The utility model discloses an auxiliary calibration device and system for a measuring trolley. The device comprises a supporting mechanism, a position adjusting mechanism, a first bottom plate and a top plate. One end of the supporting mechanism is connected with the first bottom plate, and the other end is fixed to the rail bottom of the steel rail during calibration and used for adjusting the horizontal levelness of the top plate. A clamping jaw is arranged at the bottom of the first bottom plate in the longitudinal direction, and the first bottom plate is fixed to a steel rail through the clamping jaw during calibration. Fixing bolts are arranged at the front end and the rear end of the first bottom plate in the longitudinal direction and used for adjusting the longitudinal levelness of the top plate. The position adjusting mechanism is arranged on the first bottom plate, the top plate is arranged on the position adjusting mechanism, and the position adjusting mechanism is used for adjusting the height of the top plate relative to the first bottom plate. The technical problems that an existing manual field calibration mode is high in labor intensity, large in calibration error and low in metering efficiency can be solved.

The invention relates to the technical field of electrical equipment verification, and discloses an intelligent high-voltage load equipment verification system, which comprises a main control unit, a high-voltage load simulation unit, a data acquisition unit, a data processing unit, a power supply unit, a power supply unit, a power supply unit and a power supply unit, and is characterized in that the main control unit is used for coordinated operation and data comprehensive analysis of all parts of the system; the parameter acquisition unit is used for acquiring electrical parameters and non-electrical parameters in operation of high-voltage load equipment in real time, the data analysis unit is used for deeply analyzing acquired data, evaluating equipment performance and predicting potential faults, and the man-machine interaction unit is convenient for a user to perform parameter setting, operation control and check a verification result and an analysis report. Various complex working conditions can be accurately generated through the high-voltage load simulation unit, different load characteristics and a wide parameter range are covered, the complex working conditions are truly restored through dynamic load simulation, self-adaptive adjustment and a multifunctional load combination module, the complex working conditions are highly matched with actual working loads, and verification accuracy is greatly improved.

The invention belongs to the technical field of semiconductor equipment calibration, and particularly relates to a wafer position error detection method and a wafer position error detection device, which are characterized in that a single position detection sensor is arranged on the side of a wafer transmission path so as to record and scan the non-circle center chord length and the endpoint position of the non-circle center chord length on a wafer; meanwhile, the position of the standard wafer is used as a reference standard system, so that the position coordinates of the end point positions, scanned by the position detection sensor, of the standard wafer and the to-be-detected wafer in the reference coordinate system are restored, and the deviation value of the circle center of the to-be-detected wafer in the second cavity and the circle center of the standard wafer is obtained; the position of the wafer to be measured is calibrated according to the deviation value, so that the process quality of wafer manufacturing can be improved; compared with a multi-sensor detection scheme, the wafer position calibration can be realized only by adopting a single position detection sensor, the calibration cost is lower, and replacement and maintenance are easy.

The invention discloses a relation calibration method and device of a two-axis turntable and a collimator, a medium and a product, and relates to the technical field of data processing. The method comprises the following steps: when the theodolite and the collimator are in a light focusing condition, acquiring first angle data of rotation of the two-axis turntable and second angle data of rotation of the theodolite; constructing a coordinate system conversion model according to the first angle data and the second angle data; based on the first angle data, the second angle data and the coordinate system conversion model, determining a plurality of conversion matrixes among the two-axis turntable coordinate system, the theodolite coordinate system of the theodolite and the collimator coordinate system; and determining the conversion relation between the two-axis turntable and the collimator according to the plurality of conversion matrixes. According to the invention, the two-axis turntable in the ground detection simulation system can be accurately aligned and calibrated with the collimator, reliable guarantee is provided for research, development and testing of the laser communication terminal, and the accuracy and reliability of satellite communication simulation are improved.

The invention relates to the technical field of intelligent sensors, in particular to a method and system for measuring current through an electrometer of a radiation monitor, and the method comprises the steps: obtaining a pulse current signal of the electrometer in a radiation environment, and carrying out the pulse period division of a pulse current sequence, the overshoot reactivity in each pulse period is obtained according to the difference between the maximum value and the maximum value of the current in each pulse period and the change rate between the adjacent maximum value and minimum value in the current value of each pulse period; the ringing fluctuation deviation of each pulse period is obtained by combining the fluctuation degree of the current when ringing is generated in each pulse period, the distortion coefficient of each pulse period is obtained, the current change distribution condition of a plurality of sampling moments closest to the time interval of each sampling moment is analyzed, and then the self-adaptive search window of each sampling moment is obtained; and filtering the pulse current to obtain an electrometer current measurement result. According to the invention, accurate measurement of the electrometer current in the radiation environment can be realized.

The invention relates to the field of optical system calibration, in particular to an optical camera position and attitude calibration method. According to the method, a least square method is adopted, the flatness h of an imaging assembly installation reference surface and the perpendicularity p between the imaging assembly installation reference surface and an optical lens installation reference surface are subjected to least square fitting, the correction misalignment amount delta is obtained, reference is provided for follow-up coaxial adjustment of an optical lens of an optical camera and an imaging assembly, and the calibration precision is improved. By adopting the beam splitter prism assembly, auto-collimation images of the beam splitter prism assembly can be simultaneously incident to different directions of the accurate measurement mirror assembly by only using one laser theodolite; compared with a traditional measurement method adopting a plurality of laser theodolites, the method has the advantages that the rotation error caused by mutual aiming of the plurality of laser theodolites is overcome, and the calibration precision and efficiency are improved.

The embodiment of the invention discloses a current compensation circuit, a logarithmic detector and a chip. The current compensation circuit comprises a current mirror, the current mirror comprises a first transistor and a second transistor, the first transistor and the second transistor respectively comprise a first end, a second end and a control end, and the current mirror is configured to mirror a first current flowing through the first end of the first transistor to the first end of the second transistor, the first end of the second transistor outputs compensation current; the resistance module is connected with the first end of the first transistor, and the resistance value of the resistance module and the first voltage of the first end of the first transistor are used for determining the size of the first current; the fuse module is connected with the resistor module and / or the first end of the first transistor and used for outputting a first control signal based on the fusing state, and the first control signal is used for calibrating the resistance value of the resistor module and / or the first voltage.

The invention discloses a cooling water system flow switch verification method and system, and relates to the technical field of flow switch verification, and the method comprises the steps: detecting the current flow in real time through a flow adjusting device, comparing the current flow with a preset standard flow value, and adjusting the current flow to a preset reference state; according to the working condition of a cooling water system and the characteristics of a flow switch, the cooling water flow is adjusted through a self-adaptive flow adjusting algorithm, and data collection is conducted at multiple flow points; monitoring the triggering time and the response state of the flow switch at each flow point; analyzing historical response data of the flow switch through a machine learning algorithm, and identifying a potential fault trend of the flow switch; a report is generated based on the collected data and analysis results. According to the cooling water system flow switch calibration method provided by the invention, the downtime of the cooling water system is reduced, the operation efficiency of the system is improved, and the requirement for real-time calibration in an industrial process is met. And data deviation caused by temperature and pressure fluctuation is reduced.

The invention relates to the technical field of torque sensor calibration, and particularly discloses a torque sensor calibration method and device, and the method comprises the steps: S10, fixing a rack; s20, installing a torque sensor to be calibrated; s30, a disc-shaped lever is installed; s40, the disc-shaped lever is adjusted to be in a vertical state, and the inclination angle theta of the axial direction of the torque sensor to be calibrated relative to the horizontal direction is obtained; s50, loading a standard weight, and displaying a torque value T1 on a PLC (Programmable Logic Controller); s60, calculating a standard torque value T; and S70, comparing T1 with T to obtain a torque indicating value error of the torque sensor to be calibrated, and calibrating the torque sensor through the PLC. According to the calibration method, under the condition that the torque input end of the torque sensor to be calibrated is abraded, the applied standard torque can be corrected, so that errors caused by abrasion are eliminated, and the calibration precision of the torque sensor is greatly improved.

The embodiment of the utility model provides a weather radar standard signal processor. The method is applied to radar technology. The signal processor comprises a signal processing unit, a signal control transmitting unit, an acquisition unit and a data storage and transmission unit; wherein the signal processing unit generates an intermediate frequency signal and sends the intermediate frequency signal to the signal control emission unit, the signal control emission unit generates an emission signal according to the received intermediate frequency signal, and the acquisition unit comprises five A / D converters, the four A / D converters are used for collecting high-gain / low-gain echo signals returned by transmitting signals in the horizontal channel / vertical channel and converting the high-gain / low-gain echo signals into digital signals, the remaining A / D converter is used for collecting transmitting pulses of the transmitting signals, generating transmitting sample signals and converting the transmitting sample signals into digital signals, and the collecting unit sends the generated digital signals to the signal processing unit. The signal processing unit carries out signal processing on the received digital signals and sends data after signal processing to the data storage and transmission unit, and the data storage and transmission unit stores the data after signal processing or sends the data to other systems / devices according to needs. In this way, data transmitted / received by radars of various models can be subjected to unified and normative standardized processing to realize functions of radar control, signal processing, calibration control and the like, so that the networking radar data quality has consistency, the networking radar data quality and the calibration precision of part of key parameters are improved, the calibration time interval is shortened, and the calibration efficiency is improved. In addition, the used standardized interface can transmit signals to radar transmitters / receivers of different models according to needs.

The present invention provides a calibration device and method for a 3D camera, and relates to the technical field of camera calibration. The calibration device for a 3D camera includes a calibration plate, a translation stage, and a linear structured light laser mounted on the translation stage, wherein the translation stage is used to carry a 3D camera, and the translation stage can be moved closer to or farther from the calibration plate, and a detachable groove structure is provided on the surface of the calibration plate facing the translation stage, and a groove is provided on the groove structure. The cross-sectional contour of the groove on the calibration plate is measured by triangulation using a laser line, the coordinates of the points on the cross-sectional contour are extracted, and a set of equations is established with the coordinates of the known edge points of the groove, so that the coordinate transformation matrix coefficients can be solved. According to the coordinate transformation matrix coefficients, the corresponding object coordinates can be found according to the image coordinates, which not only has high solution efficiency, but also reduces the influence of camera lens distortion and has high calibration accuracy.