Abstract: Based on the Inpho photogrammetry software, the DOM precision and DEM precision of the UAV image data of post-processed difference and point positioning under the condition of dense image control points and sparse image control points are compared and analyzed. In the test area of 1 km², 68 image control points and check points are laid. By adjusting the number and layout position of image control points of the involved calculation, the inspection points are used to verify accuracy of the generated DOM and DEM. Through the experiment, it is found that the accuracy of UAV photogrammetry results is improved remarkably based on the post-processed difference technique and the reasonable layout of the control points. In this experiment, the highest precision reaches the plane ±4 cm and the elevation is ±9 cm. Therefore, post-processed differencing technique and reasonable image control point layout are of great significance for large scale UAV digital mapping.

Key words: post-processed difference, image control point, aerial triangulation, Inpho, DEM, DOM