Accuracy assessment using different UAV image overlaps

Unmanned aerial vehicle images are considered an important tool in close-range photogrammetry for topographic map production and 3D modelling using structure-from-motion approaches. The effect of overlap percentage in vertical and integrated vertical and oblique images on accuracy is evaluated. Analysis showed that the accuracy of the photogrammetric products (e.g., digital surface model and orthoimagery) is increased with the increased overlap percentage in vertical images. The accuracy is better when oblique images are integrated into vertical images than when only vertical images are used even with the same number of images. Furthermore, the building façade is constructed, but the building suffers from noise. Increasing the number of integrated vertical and oblique images improves the accuracy of the products and provides considerable precision to 3D modelling. This study showed that the improved result is due to the increased redundancy in image matching and optimised parameters of interior orientation through self-calibration. The images are processed using Pix4D software.