基于多视角二维图像的钙质砂颗粒三维重构方法

以多视角二维图像为基础进行复杂形状颗粒三维重构。以具有复杂形状的钙质砂颗粒为样本，针对块状、条状以及树枝状等典型复杂形状颗粒进行重构，并以凸度、圆形度以及长宽比等形状指标为依托对其最终重构精度进行表征。在重构过程中，以颗粒初始投影面为基础绕轴转动获取一系列颗粒二维投影图像，并提取其边界坐标值，而后利用三维点云与所获取的二维图像轮廓坐标进行定位匹配，并删除位于二维图像轮廓外部点集，最终得到使得所有点均位于所获取的系列二维图像轮廓内。在此基础上，进一步对点云实体化处理并构建得到三维实体。通过对150个不同形状颗粒展开重构，统计发现90%以上颗粒的重构误差在10%以内，其中，误差范围最大的为树枝状颗粒，最大误差为10.84%，最小误差则小于1.00%。该方法原理简单，可有效地构建得到精度较高的复杂形状颗粒三维模型。

Approach to 3D reconstruction of calcareous sand using 2D images of multi-view

A 3D reconstruction of complex-shaped particles based on the multi-view 2D image is processed. The complex-shaped calcareous sand particles are taken as samples, and the typical complex-shaped particles such as block, strip, and dendrite are reconstructed. The final reconstruction accuracy is characterized by convexity, circularity, aspect ratio, and other shape indicators. In the reconstruction process, the initial projection surface of the particles is rotated around an axis to obtain a series of 2D projection images of the particles, and the boundary coordinates are extracted. Then, a 3D point cloud is used to match the coordinates of the obtained 2D image contours, and the set of points located outside the 2D image contours is deleted so that all points are located within the obtained series of 2D image contours. The point cloud is further materialized and constructed to obtain the 3D solid on this basis. By reconstructing 150 particles of different shapes, it is found that the reconstruction error of more than 90% of the particles is within 10%, among which, the largest error range is dendritic particles with the maximum error of 10.84% and the minimum error is less than 1%. The method is simple and it can effectively construct 3D models of complex-shaped particles with high accuracy.