Exploration and Application of High-Precision Inclined Photography Technology in Digital Collection of Geological Outcrops

With the ongoing evolution of unmanned aerial vehicle (UAV) technology in geology, particularly the emergence of oblique photogrammetry, a novel approach for creating high-precision 3D models of geological outcrops has been introduced. This technique offers a more abundant and detailed perspective compared to traditional orthophotography. To guarantee optimal data collection, an extensive preliminary survey of the surrounding area of the geological outcrop was conducted using satellite imagery. We selected the DJI Mavic 3 drone, equipped with a 4/3 CMOS sensor and boasting an effective resolution of 20 million pixels. The incorporation of a Hasselblad lens significantly enhances the image quality. During the photography process, we meticulously controlled critical parameters such as the overlap rate of images, flight altitude, and the angle of photography. The overlap rate was typically maintained between 60-70%, necessitating systematic photography from macroscopic to microscopic levels and the continual adjustment of the drone camera's tilt to capture intricate details of the outcrop from various angles, enabling the construction of a more detailed and comprehensive 3D model. Our project has digitally captured and modeled over 120 notable geological outcrops across 12 countries, including China, the United Arab Emirates, Italy, France, Germany, Spain, and Namibia, etc. We have amassed over 240,000 drone photos for 3D modeling, in excess of 7,000 panoramic shots, and more than 800 video segments featuring international experts discussing outcrops, culminating in 8000GB of data. The essence of our work is rooted in precise UAV oblique photography, and through extensive experimentation, we've established a systematic approach, achieving centimeter-level resolution. Looking to the future, our goal is to further the digitalization of classical geological outcrops, field practice bases, and world geoparks. The data and models we produce are invaluable for geological research and education, offering a more vivid and intuitive understanding of complex geological phenomena to both the academic community and the public.