基于方向包围盒投影转换的轮廓线拼接算法

基于轮廓线拼接算法重构三维模型时，由于拼接对象的复杂性，任何一种拼接方法都不能完全涵盖所有情况。为此，提出一种基于方向包围盒(OBB)投影转换的轮廓线拼接算法：首先判断多边形的顶点凹凸性，对于凹顶点，将其转换到对应的凸包上；然后计算凸包的方向包围盒，旋转平移矩形包围盒，并求包围盒内接椭圆，将每个顶点都按比例投影此椭圆上；基于投影后的点进行轮廓线拼接，寻找相邻轮廓线顶点之间的对应关系；最后还原实际坐标，进行原始模型的三维重构。

Algorithm of contours splicing based on OBB projection transformation

When reconstructing three-dimensional model based on contours splicing, due to the complexity of spliced object, any kind of mosaic method can not cover all cases. Therefore, on the premise of one-to-one splicing, this paper proposed an algorithm of contours splicing based on Oriented Bounding Box (OBB) projection transformation: First, judged the convexity-concavity of the vertices of polygon. The concave vertex was projected, to the corresponding convex hull; second, calculated the oriented bounding box of convex hull and rotated and translated the rectangular to the axis, calculated the rectangular inner concatenated ellipse; Third, projected the each vertex of polygon to the ellipse, spliced the contours based on these projection vertex. Finally, sought for the correspondence relation between vertices of adjacent contours, and used the actual coordinates to establish the original model of three-dimensional reconstruction.