3501results about How to "Improve calibration accuracy" patented technology

A field transducer (30) for determining position or orientation in a medical instrument locating system is placed at an arbitrary position or orientation with respect to a feature (62) of the instrument (46). The transducer (30) may be attached at a arbitrary location on the instrument (46), or the instrument (400, 404) may be bent as desired by the user. A transform relating position or orientation of feature of the instrument to position or orientation of the tranducer is obtained in a caliration cycle. A field transducer may be part of a disposable unit which is irrevocably altered when used with an instrument so that the unit cannot be reused.

A communication device for transmitting and / or receiving signals by using a communication antenna includes signal characteristic information detection means for detecting information regarding signal characteristics of a calibration signal which are contained in a signal received by the communication antenna, calibration means for calibrating a communication antenna chain based on the detected signal characteristic information, and cancellation signal generating means for generating a cancellation signal corresponding to a calibration signal contained in the signal received by the communication antenna based on the calibration signal. The device also includes signal cancellation-by-subtraction means for subtracting the generated cancellation signal from the signal received by the communication antenna, and receive signal processing means for processing the received signal that is diminished by the cancellation signal.

A blood pressure monitoring apparatus which continuously estimates and monitors the blood pressure by using the pulse wave propagation time can accurately estimate the blood pressure. While an estimated blood pressure is continuously calculated by using the pulse wave propagation time, the correlation between the pulse wave propagation time and the interval between feature points contained in two consecutive heart beat waveforms of an electrocardiogram is monitored. If the correlation is reversed, the blood pressure is actually measured, and the estimated blood pressure is corrected on the basis of the difference between the estimated blood pressure and actually measured blood pressure.

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

The invention discloses a satellite-borne remote sensor radiation calibration method based on atmospheric parameter remote sensing retrieval. The method includes nine steps. A surface reflectance is obtained through ground synchronous actual measurement during satellite crossing or historical data, imaging time and observation geometry parameters are obtained through remote sensing data head files, atmospheric parameters during imaging of synchronous crossing meteorological satellite sensors or related load retrieval remote sensors are utilized, the entrance pupil radiance of the remote sensors is calculated by an atmospheric radiation transmission model according to retrieval results of the atmospheric parameters, a calibration coefficient is calculated through a radiation calibration model, and thereby the on-orbit radiation calibration for a satellite-borne remote sensor is achieved. The satellite-borne remote sensor radiation calibration method based on the atmospheric parameter remote sensing retrieval is a pixel-level calibration method and has the advantages that the accuracy is high, the costs are low, simultaneously, the high frequency calibration can be achieved, historical remote sensing data can be calibrated, and the method has a wide application prospect to remote sensing data processing methods and application technical fields.

A field transducer (30) for determining position or orientation in a medical instrument locating system is placed at an arbitrary position or orientation with respect to a feature (62) of the instrument (46). The transducer (30) may be attached at an arbitrary location on the instrument (46), or the instrument (400, 404) may be bent as desired by the user. A transform relating position or orientation of a feature of the instrument to position or orientation of the transducer is obtained in a calibration cycle. A field transducer may be part of a disposable unit which is irrevocably altered when used with an instrument, so that the unit cannot be reused.

The invention discloses a binocular visible light camera and thermal infrared camera-based target identification method. The method comprises the steps of calibrating internal and external parametersof two cameras of a binocular visible light camera through a position relationship between an image collected by the binocular visible light camera and a pseudo-random array stereoscopic target in a world coordinate system, and obtaining a rotation and translation matrix position relationship, between world coordinate systems, of the two cameras; according to an image collected by a thermal infrared camera, calibrating internal and external parameters of the thermal infrared camera; calibrating a position relationship between the binocular visible light camera and the thermal infrared camera;performing binocular stereoscopic visual matching on the images collected by the two cameras of the binocular visible light camera by adopting a sift feature detection algorithm, and calculating a visible light binocular three-dimensional point cloud according to a matching result; performing information fusion on temperature information of the thermal infrared camera and the three-dimensional point cloud of the binocular visible light camera; and inputting an information fusion result to a trained deep neural network for performing target identification.

The invention discloses a polyphaser system calibration method, comprising a calibration component which is formed by three or more signalized points with known geometry in rigid motion at the work area of the polyphaser system, obtaining a plurality of images of calibration and inputting the images to a computer, extracting image coordinate of the signalized points and regarding the image point which is shot by different cameras on the same signalized points on the calibration component at certain position as a group of corresponding points, linearly recovering the projection transformation matrix of every camera in the polyphaser system according to the geometry contained in the image corresponding points and the signalized points and utilizing nonlinearity arithmetic to optimize. The device disclosed by the invention comprises a calibration part, a handle, an operation system, a work area and a polyphaser system. The invention overcomes the shortages of low efficiency, having relatively large accumulated errors and the like in the existing calibration method which needs to calibrate the cameras in the polyphaser system one by one or step by step. Further, the invention realizes calibrating the whole polyphaser system at one-time, thereby having important practical engineering value.

The present invention discloses an automatic calibration method for a robot system, comprising steps of: calibrating intrinsic parameters of a sensor and a sensor coordinate system of the sensor with respect to a world coordinate system by means of a calibration plate; and controlling a robot under the guidance of the calibrated sensor to move an original point of a tool coordinate system of a tool mounted on the robot to reach the same target point with a plurality of different poses, and calculating a transfer matrix tcpTt of the tool coordinate system with respect to a tool center point coordinate system of the robot based on pose data of the robot at the same target point. The robot can accurately move to the same target point with the plurality of different poses, improving the calibration accuracy of the robot system. Furthermore, the calibration of the robot system is automatically performed by a control program, increasing the calibration efficiency, and simplifying the calibration operation.

Provided is a measuring device and a calibration method for optical lens distortion. The measuring device comprises a single star light simulator, an adjusting rack, a to-be-tested lens, a CCD (charge coupled device) camera, a one-dimensional air flotation turntable, an angle encoder, a computer and an optical platform. The calibration method includes the steps of using a centroid localization algorithm to determine centroid position coordinates of a star point image when the to-be-tested lens is under different fields of view, establishing a calibration model for the to-be-tested lens distortion based on the distribution of the centroid position coordinates of the star point image under the entire field of view, and realizing the calibration of the distorted to-be-tested lens. The measuring device and the calibration method for the optical lens distortion has the advantages that the device is simple; the method is convenient; measurement accuracy is high; and the optical lens distortion can be easily measured and calibrated.

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 method for the automatic extraction of the position of a license plate in a vehicle monitoring image and perspective correction, and the method comprises the steps: finding an approximate range of the license plate in the image through employing the edge and color information; carrying out the linear detection of the image; determining four boundary lines forming a perspective deformation license plate through employing the regional boundary information and combining with significant straight lines; solving four intersection points of the significant straight lines, and building mapping relation between the four intersection points with four corners of a target rectangle; carrying out the reverse calculation of a perspective correction matrix, and completing the perspective correction of a license plate. The method obtains the positions of four corners of a license plate with perspective distortion, builds the mapping relation between the four corners of the license plate with perspective distortion and the four corners of the target rectangle, calculates a perspective transformation matrix, and completes the perspective correction of the license plate. Compared with an affine transformation method based on horizontal and vertical rotation, the method truly describes the perspective transformation, and guarantees the higher license plate image correction precision. Compared with an affine transformation algorithm, the method can detect the perspective distortion information of the license plate, also can precisely locate the boundary corners of the license plate, calculates the perspective transformation matrix, and accurately achieves the perspective correction of the license plate.

The invention discloses a method for calibrating a spatial coordinate measuring system of an electronic theodolite, which aims to meet the need that the measuring system of the electronic theodolite calibrates in the range of tens of meters in any direction at an angle of horizontal 360 DEG and pitching + / -45 DEG. The method comprises the following steps of: placing instruments and targets; 2, using a laser radar scanner to assign a value to the targets to form a standard instrument group; step 3, the calibrated system of the electronic theodolite measures each target to obtain measured values; step 4, converting the measured values of the electronic theodolite to a measurement coordinate system of the laser radar scanner; and step 5, comparing the converted measured values of the electronic theodolite with a standard value thereof, and obtaining the measurement deviation and measurement uncertainty evaluation of the measuring system of the electronic theodolite through software analysis. The method meets the need that the measuring system of the electronic theodolite calibrates in the range of tens of meters in any direction at the angle of horizontal 360 DEG and pitching + / -45 DEG.

The invention discloses a large-view-field depth measuring system and method based on omni-directional structured light. The system comprises a camera, a hyperboloid reflector, at least four projectors, a three-axis moving platform and a computer, wherein the projectors and the camera are respectively and fixedly arranged on the three-axis moving platform; the projectors are uniformly distributed around the camera; the three-axis moving platform can move along an x axis, a y axis and a z axis; coding structured light projected by the projectors irradiates a measured scene target object, is reflected by the hyperboloid reflector and then enters the camera for imaging; the formed image is acquired and processed by the computer to obtain scene depth information. By adoption of the hyperboloid reflector to reflect for imaging, the view field range of the camera is widened; by combining the large-view-field depth measurement with visual measurement of the structured light, visual three-dimensional perceived measurement of a wide view field is realized; the system is simple in structure and high in practicality; the measurement task can be finished by the camera and the projectors without perfect alignment; the calibration of the camera and the projectors is finished by adopting a plane white board; the simplicity in operation and higher calibration precision are realized.

The invention relates to a composite static start-stop method mass flowmeter calibration system which is used for checking the flow rate of a mass flowmeter, is a calibrating apparatus adopting the mass flowmeter that is nationally and legally prescribed and can check the main characteristics and accuracy index of the mass flowmeter. The calibration system comprises a water tank, a current stabilizer, a regulating valve, stop valves and an electronic scale, and is characterized in that a flow rate pump set is connected between the water tank and the current stabilizer, the two sides of the flowmeter to be measured are respectively connected with standard flowmeter sets, the two ends of the regulating valve are respectively provided with the stop valves, one end thereof is connected with the water tank, and the other end is connected with the current stabilizer which is connected with a weighing container; the standard flowmeter sets, the flowmeter to be measured, the regulating valve and the electronic scale are connected with a computer. The calibration system has the advantages of weighing method and standard scale method, so as to have high accuracy in calibration and working efficiency and the like; furthermore, a static start-stop method is adopted to calibrate the mass flowmeter, so that the accuracy error caused by inconsonant positive and negative strokes of a steering gear can be avoided.

A process and associated apparatus for performing defective pixel correction in a radiation detector having a plurality of radiation sensors arrayed in rows and columns. The process and associated apparatus are specifically directed to correcting defects consisting of a plurality of adjacent pixels arrayed along and connected to a common electrode forming a bad pixel line. The pixel correction is accomplished by identifying the bad pixel line, forming a window of a plurality of pixel lines co-extending along the bad pixel line; identifying a limited number of adjacent pixel lines adjacent to the bad pixel line as also being bad pixel lines; preferably subdividing the window pixels into smaller windows along the bad pixel line, deriving correction coefficients for all bad line pixels in each subdivision from the good pixels in each subdivision and using the correction coefficients to correct the pixels in both the original bad line and in the adjacent bad pixel lines.

The invention discloses an in-orbit moving target detecting method with space-based radar and infrared data fusion. The method includes the steps that when an infrared detecting system is used for detection, background suppression is carried out on each frame in an infrared image sequence by adopting a filtering method based on the morphology, self-adaptive threshold segmentation is carried out on images obtained after background suppression, a single frame detection result is extracted, a multi-frame target is determined through a tracking algorithm, and whether the detection result is a real target or not is judged to obtain the detection result of the multi-frame target; during radar detection, pulse doppler (PD) is adopted for processing. After time calibration and space calibration are carried out on the obtained infrared and radar target information, data fusion is carried out on the information by adopting a measurement fusion method, and track prediction is carried out on fused data to obtain the estimated position of the target.

An apparatus and method for calibrating transmission paths in a multicarrier communication system using multiple antennas are provided. In the transmission path calibrating apparatus, a calibration processor generates reference signals to estimate distortions in phase and amplitude in transmission paths, allocates the generated reference signals to subcarriers which are different in each of the transmission paths, and calculates calibration vectors for the transmission paths using the generated reference signals and received reference signals received through the transmission paths. A baseband module IFFT-processes the generated reference signals allocated to the subcarriers and sends the IFFT signals in the transmission paths.

The invention, which belongs to the computer vision field, provides a flexible-target-based close-range large-field-of-view calibrate method of a high-speed camera and relates to a close-range large-field-of-view binocular-visual-sense camera calibration method in a wind tunnel. According to the method, a flexible target is used for fill an overall calibration view field for calibration; the internal region of the target is formed by a planar chessboard mesh and distances between angular points of the chessboard mesh are known; the external region of the target is formed by cross target rods perpendicular to each other and a plurality of coding marking points with known distances are distributed on the target rods uniformly. During calibration, regional and constraint calibration is carried out on a high-speed camera by using different constraint information provided by different regions of the target. When the internal region of the target is calibrated, calibration is carried out by using a homography matrix; and the external region is calibrated by using distance constraints of the coding marking points. According to the invention, the cost is lowered and the operation portability is realized. During calibration, distortion of different regions is considered by using the regional and constraint camera calibration method, so that the calibration precision is improved.

The invention discloses a digital image correction method for a continuous variable-focal-length optical imaging system. The digital image correction method comprises the steps of acquiring planar template images which are photographed by an image camera in a plurality of discrete focal lengths, performing off-line calibration on a distortion parameter which corresponds with each focal length of a variable-focal-length lens; performing curve fitting on the distortion parameter which corresponds with each focal length for obtaining a fitting formula or establishing a distortion parameter lookup table; according to the actual operation focal length of the image camera, obtaining a lens distortion parameter which corresponds with the actual operation focal length through the distortion parameter lookup table or calculation by the fitting formula; and constructing a projection conversion relationship from an image camera coordinate system to a map coordinate system according to position gesture data and the lens distortion parameter in imaging of the image camera, and performing resampling on the pixel brightness value after coordinate conversion for obtaining an orthographic projection image after correction on the squint deformation and lens distortion. The digital image correction method realizes a purpose of simultaneous correction for squint trapezoidal distortion and variable-focal-length nonlinear distortion in the variable-focal-length imaging system.

The invention discloses a method for optimizing ultrasonic probe imaging plane space position calibration and belongs to the field of medical ultrasonic three-dimensional imaging and ultrasonic image fusion. The method is an optimizing method for calibrating the transformation relation of the space position of an ultrasonic probe imaging plane and the space position of a space position sensor, namely the space transformation matrix. Under the assisting of a three-dimensional positioning system, the method includes steps of: 1, constructing a three-dimensional positioning system; 2, manufacturing an N-line model; 3, building a coordinate system set of the positioning system; 4, calibrating a placing space position of a water tank model; 5, collecting ultrasonic images under different positions; extracting N-line marks and calculating the ultrasonic plane position; 7, mapping N-line mark points on the ultrasonic images onto a three-dimensional space plane; 8, performing registering on three-dimensional coordinate points on the imaging plane and an N line on the water tank model; 9, performing optimization calculation; and 10, calculating the optimum transformation between an imaging plane and the position sensor. The method has the advantages of reducing errors in space position calibration of the imaging plane.

The invention discloses a measuring method for length, width and height of a vehicle based on an RGB-D camera. The method comprises the steps of acquiring a clear vehicle image in a camera short-distance mounting manner, calibrating the camera according to a calibrating method based on a disappearing point, obtaining an internal parameter and an external parameter of the camera, realizing three-dimensional point cloud conversion of a vehicle target in a world coordinate system through a camera depth image solution, and acquiring three-dimensional coordinate information of the external surfaceof the vehicle; acquiring the three-dimensional coordinate of the external surface of the vehicle by means of prior knowledge and an image processing method, splicing a vehicle image according to sequence patterns in a vehicle motion process through a registering method, and realizing three-dimensional measurement to the profile of the vehicle. The measuring method overcomes defects of high equipment requirement and tedious operation in a traditional method and realizes high calibration precision. The actual displacement of the vehicle is comprehensively analyzed through a matching relation ofpoints which correspond with the same position of the vehicle in the image sequence, thereby realizing relatively high registering precision. The measuring method further has advantages of realizingaccurate splicing of the vehicle side surfaces, reducing vehicle length measurement error and improving accuracy in splicing the vehicle side surfaces.

An encoded calibrating plate is fixed on the working environment of the robot arm and has a chessboard pattern with each square in the chessboard pattern being an encoding. The encoding indicates direction or position on the encoded calibration plate. A visual system of the robot arm captures an image of the encoded calibrating plate, calculates the coordinates encoding of the encoded calibration plate, and positions the visual system to calibrate a positioning error of the robot arm and the visual system.

The invention discloses a method for marking IMU each item error coefficient precisely, which comprises the following steps: marking the gyroscopic scale factor and gyroscopic installment error in the IMU error model through dynamic calibration experiment; substituting the error value in the symmetrical 24 position static calibration experiment of adjacent position; adapting the symmetrical position error cancellation law to mark IMU residual each item error coefficient within gyroscopic constant drift, error item of gyroscope and acceleration, accelerometer constant bias, accelerometer marking factor and accelerometer fixation error.

The invention belongs to the technical field of measurement, and provides an optical vision measuring system with a wide-field structure and a measuring method thereof. The measuring system consists of an optical vision sensor 7 with a wide-field structure, a computer, a calibration target 8 and a calibration target 9, wherein the optical vision sensor 7 with the wide-field structure comprises a camera 1, a regular rectangular pyramid reflecting mirror 2 and four structured light projectors 3, 4, 5 and 6. The method comprises the following steps of: projecting structured light onto a wide-field scene object in a way of splicing a plurality of linear structure light projectors; forming a deformed structural light bar on the surface of a measured object; receiving the structural light bar by using the camera 1 after being reflected by the regular rectangular pyramid reflecting mirror 2; acquiring a formed image with the computer; processing the acquired image by using the computer; extracting the image coordinate of a central line of the structural light bar; and calculating the three-dimensional coordinate of a light bar point on the surface of the measured object to obtained wide-field scene information according to a measurement model. In the system, the regular rectangular pyramid reflecting mirror is used for reflecting and imaging, so that the view field range of the camera is expanded; and the system and the method are combined with a structured light vision measurement technology, so that three-dimensional sensing measurement of wide-field scene information is realized.

The invention discloses an on-track correcting device of a space-borne phased array transmitting antenna, which is characterized in that on-track correcting is started by a correcting control module to trigger a reference signal generation module to generate correcting reference signals; radio frequency transmitting signals are output after the correcting reference signals are processed by the radio frequency transmitting front terminals of each channel of a multi-channel radio frequency transmitting front terminal module; the radio frequency transmitting signals of some channel are fed back by a radio frequency feedback module; the digitized feedback signals of the channel are output after being processed; an amplitude-phase error calculation module calculates the amplitude and the phase error between the feedback signals and the correcting reference signals of the channel according the maximum likelihood estimation rule; an amplitude-phase correcting module compensates the amplitude and the phase error of the channel according to the amplitude and the phase error obtained by calculation; and the channels are successively compensated in this way, and the amplitudes and the phases of the channels approach to be consistent.

To provide a sheet conveying apparatus capable of improving a correction accuracy for conveying a sheet. Accordingly, a “sheet conveying apparatus for conveying a sheet using a sheet conveying unit arranged along a sheet conveying path” according to the present invention includes a skew detecting unit for detecting skew of the sheet conveyed along the sheet conveying path with respect to a sheet conveying direction, a skew correcting unit that moves in a direction for correcting the skew of the skewed sheet with the sheet nipped therein on the basis of a detection signal from the skew detecting unit, and a guide unit for regulating side edges of the sheet and guiding the sheet to the skew correcting unit, in which, when the skew correcting unit moves in the direction for correcting the skew of the sheet, the guide unit is moved in the direction for correcting the skew of the sheet.

A disclosed hand-eye calibration method employing a two-dimension laser vision sensor and a robot comprises the following steps: step A, establishing a mathematic module of a calibration algorithm; step B, making enforcement operation step for hand-eye calibration. The step of establishing the mathematic module of the calibration algorithm realizes derivation of the mathematic module of the calibration algorithm; and the step of making the enforcement operation step for hand-eye calibration solves the concrete enforcement operation flow in the h and-eye calibration process by employing the two-dimension laser vision sensor and the robot. The method possesses the advantages of being simple, practical, agile, good in precision and the like.

The invention discloses a rapidly converged scene-based non-uniformity correction method, wherein the aim of non-uniformity correction is achieved by minimizing interframe registration error of two adjacent images. The method mainly comprises the following steps of: initializing gain and offset correction parameters and acquiring an uncorrected original image; acquiring a new uncorrected original image, and carrying out non-uniformity correction on the new uncorrected original image and the previous uncorrected original image by utilizing the current non-uniformity correction parameters; obtaining relative displacement, scene correlation coefficient and interframe registration error of two corrected images by utilizing an original point masking phase correlation method; and updating correction parameters along the negative gradient direction by adopting a steepest descent method. The method disclosed by the invention has the advantages of high correction accuracy, fast convergence speed, no ghost effect and low calculated amount and storage content and is especially applicable to being integrated into an infrared focal plane imaging system, and the effect of improving imaging quality, environmental suitability and time stability of an infrared focal plane array is achieved.

Systems and methods for testing a laser eye surgery system are provided. Methods include establishing an image scale based on a calibration pattern, imageably altering a series of regions of a test surface with the laser system, laterally redirecting a laser beam to form a test pattern, imaging the test pattern, determining a lateral redirecting characteristic of the beam delivery system, and qualifying or calibrating the beam delivery system. Systems can include an input module that accepts an input member such as a calibration pattern parameter, a calibration pattern image, an intended pattern parameter, a test pattern image, an imaging device position, a calibration pattern position, a test pattern position, and a beam delivery system position, a characterization module that determines a beam delivery system characteristic, and an output module that generates a calibration for the beam delivery system of the laser eye surgery system.