Method and device for automatically comparing point cloud differences between three-dimensional point cloud and BIM (Building Information Modeling)

The invention discloses a point cloud difference automatic comparison method between a three-dimensional point cloud and a BIM, and the method comprises the steps: obtaining first point cloud data in a collection environment collected by a laser radar, and second point cloud data in the collection environment generated by the BIM; then, an octree of the first point cloud data is established by adopting a PCL library, and a spatial resolution is preset when the octree of the first point cloud data is established, so that cube space division is performed according to the spatial resolution; finally, inputting the second point cloud data into an octree, and searching in a cube space corresponding to the octree in sequence according to each point cloud in the second point cloud data so as to obtain a difference region between the first point cloud data and the second point cloud data; therefore, the difference between the two point cloud data sets is compared through the octree data structure, and the changed reg