Round mark point center picture projection point position acquiring method for positioning video camera

Abstract

The invention provides a method for acquiring the position of image projection point of a centre of a circular mark point used in orientation of video camera. The characters include that: the method for setting the circular mark point is: concentric circles are set, and the concentric circles consists of a big circle and a small circle; an inscribed circle which is inscribed in the small circle is arranged in the inner part of the small circle in the concentric circles, and the diameter of the inscribed circle is equal to the radius of the small circle in the concentric circles; the method for acquiring the position of image projection point of the centre of circular mark point is: image is acquired, filtering, division of threshold value, edge checking, profile extraction and ellipse fitting of least square method are carried out on the image for acquiring the line connecting of the centre of the ellipse in the image that the big circular and the small circular in the concentric circles are corresponding to, the line connecting and the edge of the ellipse in the image that the inscribed circle of the small circle in the concentric circles corresponds to intersects at two points, and the point of intersection near to the centre point of the ellipse in the image which the big circle of the concentric circles is corresponding to is the position of the projection point of the centre of the big circle and the small circle in the concentric circles.

Description

Method for Acquiring the Position of the Image Projection Point of the Center of the Circle Marking Point Used for Camera Positioning technical field The invention relates to the field of computer vision detection, in particular to a method for acquiring the position of an image projection point at the center of a circle mark point for camera positioning. Background technique One of the basic tasks of computer vision is to calculate the three-dimensional information of the object in the field of view from the image captured by the camera, so as to reconstruct and recognize the three-dimensional object. The relationship between the three-dimensional geometric information of the object surface point and its corresponding point on the image is determined by the imaging model of the camera. The process of establishing this geometric model is actually the solution process of the camera parameters. Therefore, the calibration of camera parameters is the premise and key of this mo...

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Problems solved by technology

In the document "AFourstep Camera Calibration Procedure with Implicit Image Correction". (Janne Heikkila, Olli Silven, IEEE Proceedings of Computer Society Conference on Computer Vision and Pattern Recognition, 1997: 1106~1112). It is pointed out that the circle will transform into an ellipse during the perspective projection transformation process, and the center of the ellipse in the image is not the circle in space. The real position of the projected point of the center of the circle in the image, that is, there is a deviation of the center of the two, so when using a circle as the mark point on the calibration plate, it is necessary to correct and compensate for the deviation of the center of the circle, and a method is given in the literature The method of correcting the deviation of the center of the circle, this method needs to calibrate the camera first to obtain the positional relationship between the calibration object and the camera, and then perform calibration again to realize the compensation of the deviation of the center of the circle, and the amount of calculation is significantly increased

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