1. A computer-implemented method for processing a point cloud using a computing device, the method comprising: determining a straight line fitted by the point cloud as a benchmark line, the point cloud comprising border points of a workpiece; determining an inflection point in the point cloud that is used to fit the determined benchmark line; determining whether a vertical distance between the determined inflection point and the determined benchmark line is greater than a preset filtration value; deleting needless border points in the point cloud, and obtaining a remainder point cloud that does not include the needless border points in the point cloud, if the vertical distance between the determined inflection point and the determined benchmark line is less than or equal to the preset filtration value, a distance between the needless border point and the determined benchmark line being greater than a predetermined distance value; or dividing the point cloud into two sub-point clouds using the determined inflection point, if the vertical distance between the determined inflection point and the determined benchmark line is greater than the preset filtration value; and deleting one sub-point cloud having a number of the border points less than a preset number, and setting the other sub-point cloud having the number of the border points greater than or equal to the preset number as a remainder point cloud.