The invention relates to an external parameter calibration method of a high-definition panoramic camera of a mobile measuring system. The operation steps are as below: selecting a plurality of panoramic photos, selecting a plurality of features in a single panoramic photo, acquiring image coordinates of the features, and while selecting absolute coordinates corresponding to the features in point cloud data; based on the POS position and attitude of the panoramic camera at the moment of photographing, converting the absolute coordinate to a coordinate under carrier coordinate system; according to the position and attitude initial value of the panoramic camera in the carrier coordinate system, converting the coordinate under carrier coordinate system to a coordinate under panoramic camera coordinate system, acquiring the pixel value according to the internal calibration parameters of panoramic camera, calculating the difference, and acquiring a residual error value of each same name feature; calculating the mean square error of an adjustment result, and if the mean square error is greater than a threshold value, checking the residual error value of the same name feature, excluding the same name feature with larger residual value, and re-selecting the same name feature until the mean square error is less than the threshold value. The method provided by the invention can ensure the precision and reliability of system data acquisition.

External parameter calibration method of high-definition panoramic camera of mobile measuring system

The invention belongs to the field of three-dimensional reconstruction technology, and relates to a three-dimensional reconstruction method. The three-dimensional reconstruction method is combined with binocular stereo vision technology, structured light technology and rotating platform technology and has advantages of high precision, high speed and low cost. Compared with binocular stereo vision, the three-dimensional reconstruction method has advantages of higher reconstruction speed, higher precision and high effect to an area without abundant object surface patterns. Compared with traditional structured light technology, a system according to the three-dimensional reconstruction method is advantageous in that a trouble in projector calibration is not required; a second camera replaces a projector; accuracy in camera calibration is higher than accuracy in projector calibration; and better reconstructed three-dimensional point cloud is realized. A rotating platform splicing algorithm is utilized in multi-visual-angle point cloud splicing. Compared with a traditional ICP registration method, the three-dimensional reconstruction method has advantages of higher point cloud splicing speed, no requirement for initial point cloud data, simple operation and no requirement for artificial participation.

Three-dimensional reconstruction method

The invention discloses a high-precision camera calibration method via a low-precision 2D planar target. The method comprises the steps that internal and external parameters, a lens distortion coefficient and the coordinates of control points in a world coordinate system are adjusted and optimized in a light beam method, and the object-point coordinates of the control points are optimized together in the parameter optimization process; and 2) after adjustment, two real distances in the surface of a calibration board and the adjusted distance are used to calculate a proportion factor, the proportion factor is multiplied by an adjusted translation vector to obtain a final value of a translation vector parameter, and calibration is completed. The object-point coordinates of the control points are optimized together two real distances of the control points are used to calculate the proportion factor between real coordinate and the calculation coordinates of the control points, distance between the translation vector calculated value and real value in the camera external parameter and the control point coordinate is eliminated, and the calibration precision for the translation vector in the external parameter of the camera is improved.

High-precision camera calibration method via low-precision 2D planar target

The invention provides a three-dimensional reconstruction method based on image sequences. The method comprises the steps of firstly obtaining a two-dimensional image sequence of a target object by using a camera; secondly, reconstructing two images; thirdly, calculating the common matching points of three adjacent images from the first image; fourthly, performing transformation of coordinates and transformation of scale; fifthly, eliminating accumulated errors; sixthly, adding new images successively and repeating the steps 3-5 until the whole two-dimensional image sequence is processed. Based on the accurate reconstruction of two images, the reconstruction results are blended in the same model finally; the matching points of three adjacent images are calculated according to the trifocal tensor, the common points of two adjacent images in the three images are reconstructed and the projection depth can be obtained through two groups of common three-dimensional points; the reconstruction results are corrected through ICP, so that the error accumulation is effectively avoided; error matching is eliminated through the dense matching algorithm based on region growing.

A three-dimensional reconstruction method based on image sequences

An embodiment of the invention discloses a face image processing method and a face image processing device. The face image processing method comprises the steps of: determining two-dimensional coordinate numerical values of two-dimensional key points extracted from a two-dimensional face image to be processed in an imaging plane coordinate system; extracting three-dimensional key points of a three-dimensional face model; determining three-dimensional coordinate numerical values of the three-dimensional key points in a world coordinate system; acquiring a focal length of a camera when shooting a two-dimensional face image; calculating a solution of a rotation matrix R and a solution of a translation vector T according to the two-dimensional coordinate numerical values, the three-dimensional coordinate numerical values and the focal length; acquiring a solution of a camera inner parameter matrix A; substituting the solution of the rotation matrix R, the solution of the translation vector T and the solution of the camera inner parameter matrix A into a formula: C=A*[R T], and calculating a solution of a projection matrix C; and rotating a face of the two-dimensional face image according to the solution of the projection matrix C and surface constants of the three-dimensional face model, so as to obtain the face-rotated two-dimensional face image. The face image processing method and the face image processing device realize the effect of rotating a face of the two-dimensional face image at a predetermined angle.

Face image processing method and device

The invention discloses an object three-dimensional information acquisition method based on digital close range photography. According to the method, some code mark points are placed in any scene, and calibration is performed on internal parameters of a camera through a self-calibration algorithm; when three-dimensional reconstruction is performed on an object, the digital camera is held in hand to shoot the object from different angles to obtain two pictures, then an SIFI key point detection method is used for detecting coordinate information of key points on the object, and calibration of external parameters of the camera is completed; a light stream detection method is used for detecting matching points, corresponding to pixel points on one picture, on the other picture, and a double-view reconstruction method is used for obtaining three-dimensional information of the object according to the matching points, the internal parameters of the camera and the external parameters of the camera. Additional equipment such as a laser and a projector is needed in a traditional three-dimensional measurement method for assisting completion of three-dimensional reconstruction, while in the object three-dimensional information acquisition method, the picture light stream detection method instead of the equipment is adopted to obtain information of the matching points on the object, therefore, an active three-dimensional reconstruction mode is achieved, hardware cost is reduced, and the method is convenient to realize.

Huang Huiming

Papers

Object three-dimensional information acquisition method based on digital close range photography