Effect of image control point layout on the accuracy of real-world modeling of small-scale irregular areas of UAVs

The layout and number of image control points have an important impact on the accuracy of real-world modeling. In this paper, a 0.25 km² irregular area in Linquan County, Fuyang City is selected as the experimental area, and two irregular verification areas (0.27 and 0.28 km²) are selected. The real-world model is constructed according to three different image control point layout methods: edge layout, edge plus a small center layout, and center layout. The characteristics of the influence of the number of image control points and the layout position on the accuracy of the model are compared and analyzed. The results show that: 1) The accuracy of the model can only be effectively guaranteed when the convex polygon surrounded by the image control point line contains the entire irregular measurement area. 2) Under the requirements of 1∶500 scale mapping accuracy, five image points are arranged at the edges as the best point layout method, which meets the modeling requirements of high efficiency, high precision and low cost. 3) In the case of ideal placement of image control points, increasing the number of layouts can not significantly improve the accuracy of the real-world model. Image control points should be arranged as needed.