36results about How to "Achieve high-precision calibration" patented technology

The invention discloses an intelligent vehicle laser sensor and an online camera calibration method. Laser data and image data are accurately calibrated via the steps of camera calibration, offline calibration of a three-dimensional laser sensor and an image sensor, time alignment of laser data and image data, and online alignment of the laser sensor and the image sensor. The calibration system can be applied to multiple different road conditions and scene, to achieve online high precision calibration of laser and an image. After the laser and the image are calibrated, the information of the two sensors can be used for comprehensively analyzing a barrier and making an accurate decision, so that the method has is significant in sensing technology of an intelligent vehicle. Therefore, the technology can be widely applied to the fields of driverless vehicle visual navigation and intelligent vehicle visual assistance driving.

The invention discloses an unsmooth dynamic compensation method for an ultralow-frequency horizontal vibration table guide rail. The unsmooth dynamic compensation method comprises the following steps: measuring unsmooth dynamic characteristics of the ultralow-frequency horizontal vibration table guide rail and output uori t of a calibrated acceleration sensor in real time by taking a horizontal direction as reference; constructing a guide rail unsmoothness dynamic compensation system, and removing a gravitational acceleration component in the output of the calibrated sensor generated by pitching of a sliding table from the original output of the calibrated sensor in real time in the vibration calibration process; calibrating a calibrated acceleration sensor by adopting the compensated output ucomt of the calibrated sensor, calculating to obtain a compensated amplitude-frequency curve, and finishing vibration calibration of the calibrated sensor. The unsmooth dynamic compensation method has the advantages that the calibration result deviation of the acceleration sensor with zero frequency response caused by guide rail unsmoothness based on the ultralow-frequency horizontal vibration table can be compensated in real time in the vibration calibration process, so that the precision of ultralow-frequency vibration calibration is improved.

The invention discloses a large visual field camera calibration method based on four sets of collinear constraint calibration rulers and belongs to the field of optical measurement. The calibration method comprises steps of arranging four sets of collinear constraint calibration rulers in a large optical measurement field; solving distortion parameters by using unlimited characteristics of the cross ratio and straight line constrains; linearly solving the initial value of the calibrated parameter via the calibrated control point in the space; and at last by combining the distortion coefficients and the calibrated initial value and using the L-M optimization method, performing overall optimization with the goal of minimizing the re-projection error so as to get the calibrated precise result of the large visual field camera. According to the invention, by flexibly arranging the calibration control point in the large view field measurement space and combining the four sets of collinear constraint calibration rulers, overall optimization is performed on the calibrated results, high precision calibration for the large view field camera is achieved and the calibration method has a wide application prospect.

The invention provides an online calibration method of a magnetic sensor for an unmanned aerial vehicle, which can solve the calibration problem of the magnetic sensor in a complicated magnetic ring environment. After being installed, a product makes one-time horizontal circular motion on an application device without being disassembled to realize the high-accuracy calibration of magnetic course parameters. The online calibration method has the beneficial effects that the operation and maintenance cost of a navigation device in the fields such as the unmanned aerial vehicle and an unmanned boat can be greatly decreased.

The invention discloses an REVO measuring head B-axis zero error calibration method applied to a non-orthogonal coordinate measurement system and belongs to the field of precision test technologies and instruments. The method comprises the steps that a square ruler is placed on a flat plate which is placed horizontally, and one working face M of the square ruler is fixed after being adjusted to beparallel to the X-direction of a measuring machine; a flat ruler is fixed after being closely attached to a working face N perpendicular to the working face M of the square ruler; three principal axes of the measuring machine are kept static, an A-axis of an REVO measuring head is placed at an appropriate position, and a B-axis of the REVO measuring head rotates to detect two symmetric points onthe flat ruler; and according to calculation of B-axis angles of the two detection points, a zero error of the B-axis of the measuring head can be calibrated. According to the method, under the statethat the three principal axes of the measuring machine are static, the situation that the angle of a joint arm is changed due to measuring force generated in the calibration process, and consequentlyan additional calibration error is introduced is avoided, high-precision calibration of the zero error of the B-axis of the REVO measuring head is realized, and the method can be applied to precisionmeasurement.

The invention discloses a satellite image geometric calibration method considering different longitude and latitude areas. The method comprises the following steps: acquiring a satellite image set with different sun heights in each longitude and latitude area in the same orbit; acquiring a control point in the satellite image set based on the control data of each longitude and latitude area; selecting a control point in one of the reference sun altitude images, and obtaining camera calibration parameters of the sun altitude based on a first geometric calibration model; constructing attitude error compensation models of different sun altitudes, and establishing a second geometric calibration model considering different latitude and longitude regions; using control points in other sun altitude images to obtain attitude compensation parameters; and updating the calibration file based on a second geometric calibration model according to the camera calibration parameters of the reference sun altitude and the attitude compensation parameters of different sun altitudes. According to the invention, unified calibration of satellite images of different longitude and latitude areas can be considered, and accurate calibration of satellite images of different sun heights on the whole satellite orbit is realized.

The invention relates to the technical field of computer vision, and particularly discloses a multi-head panoramic camera combined calibration method. The method comprises the following steps: placing MPCs on a two-dimensional turntable to carry out rotary photographing and calibration on a checkerboard; and dividing a calibration process into two successive stages, wherein the previous stage is rotation sequence image calibration of side-view cameras, and the latter stage is multi-view geometric calibration of a center camera. According to the method, high-precision calibration of external parameters of an MPC can be realized only by using a common two-dimensional numerical control turntable and a single checkerboard, the cost is low, the operation is simple, the requirement on a real-time environment is low, the dependence on a 3D calibration field is successfully eliminated, and the method has a good application value.

The invention relates to a camera online calibration method based on a small target blurred image, which comprises the following steps: enabling a high-precision small circular light-emitting point target to be close to a lens as much as possible, and ensuring that the target obtains a large image proportion and a placement angle; adjusting a camera aperture and exposure time to obtain an identifiable target image; establishing a target feature point positioning uncertainty mathematical model, and solving the positioning uncertainty of each feature point; By taking target feature point positioning and parameter uncertainty as constraints, solving high-precision solutions of internal and external parameters of the camera through a nonlinear optimization method; according to the method, thefocusing space and the target size of the camera do not need to be considered, and the ultrahigh-precision calibration of the camera can be realized under the conditions of large image blurring and noise only by placing a very small high-precision target at a position close to a lens. The method is suitable for online calibration of large-view-field and shallow-depth-of-field cameras and even cameras in use, and has great flexibility and adaptability.

The invention discloses a multi-parameter model of an articulated arm coordinate measuring machine and a calibration method, relates to the technical field of precision measurement, expands a 23-itemerror model of an original articulated arm coordinate measuring machine into a 59-item error model, greatly increases the number of structural parameters of the error models of the articulated arm coordinate measuring machine, and improves the precision of the articulated arm coordinate measuring machine. According to the articulated arm coordinate measuring machine multi-parameter model and the calibration method provided by the invention, the shafting shaking error term is added on the basis of the original articulated arm measuring machine error model, the articulated arm coordinate measuring machine multi-parameter error model is established, and high-precision calibration of the articulated arm coordinate measuring machine is realized.

The invention discloses a projector out-of-focus correction method based on edge perception. According to the method, a projector-camera system is adopted, and a lens of a projector and a lens of a camera face the projection surface; inputting the special input image into a projector, projecting and irradiating the special input image onto a projection surface, and acquiring a projection result projected and irradiated onto the projection surface by the projector as an output image by a camera; and performing out-of-focus convolution kernel calibration by using the special input image and theoutput image to obtain a compensation picture, and performing correction compensation on the to-be-projected picture of the projector by taking the compensation picture as the input of the projector to obtain a clear projection result after out-of-focus compensation. The physical focal length of the projector does not need to be adjusted; according to the technical scheme, the clearness of the out-of-focus projection result of the projector can be realized only by processing the original picture input into the projector, the requirements of using the projector in complex application scenes such as thermal out-of-focus and large-amplitude height change of the projection surface of the projector can be met, and the applicability of the projector equipment is expanded to a certain extent.