Shovel loading volume obtaining method and system based on material pile three-dimensional reconstruction before and after shovel loading

The method comprises the following steps: collecting a binocular image of the surface of a material pile before shoveling; feature point detection, description, matching and purification are carried out on the binocular image, sparse matching feature points and parallax are obtained through calculation, and triangular mapping parameters are obtained; constructing a sparse three-dimensional point cloud based on the sparse feature points and the parallax; based on the sparse three-dimensional point cloud and the triangular mapping parameters, a dense three-dimensional point cloud model of the surface of the material pile before shovel loading is constructed; binocular image acquisition is carried out on the surface of the material pile shoveled by the engineering machinery, and a dense three-dimensional point cloud model of the surface of the shoveled material pile is constructed; performing point cloud downsampling and point cloud registration on the dense three-dimensional point cloud model on the surface of