Abstract:

Spatial circle center coordinate extraction is one of the key technologies of vision measurement systems. The ellipse center of multi-view image needs to extract according to the spatial center coordinates. According to the perspective projection ellipse center is not the real center of spatial circle, a spatial center extraction method based on single plane circular image is proposed. Firstly, the space conic equation is constructed according to the viewpoint and the imaging ellipse, and then the front surface of cone is constructed. The spatial circle equation is solved according to the bottom surface. Finally, the correct spatial circle equation is found according to the parallel plane and the real radius. This method avoids the problem of solving the spatial centroid projection coordinates, and only needs a single image to solve the spatial center coordinates. Experimental results show that the proposed method can accurately solve the circular object center space coordinates, which effectively improves the efficiency and accuracy.

Key words: spatial circle, measurement, multiple viewing angles, cone, coordinates

摘要：

空间圆圆心坐标提取是视觉测量系统的关键技术之一。为了解决空间圆心坐标需要提取多视角图像椭圆圆心，而由于透视投影椭圆圆心并不是空间圆心像点的问题，提出了一种基于单张平面圆图像的空间圆心提取方法。该方法首先基于圆锥曲线特性根据相机光心坐标与成像椭圆像素坐标构建了空间圆锥方程，再根据圆锥方程构建出圆锥正底面表达式，根据正底面表达式求解出与空间圆所在平面平行的平面方程，最后根据平行平面与实际目标直径找出正确空间圆方程。该方法避免了空间圆心投影坐标求解与需要多张图像求解圆心的问题，只需单张图像即可求解出空间圆心坐标。实验结果表明，该方法能精确求解圆形目标中心空间坐标，有效提高了三维坐标的求解效率与精度。

关键词: 空间圆, 测量, 多视角, 圆锥, 坐标