TESTING THE ACCURACY OF POLYCAM 3D SCANNING SOFTWARE ON LIDAR AND OPTICAL PHOTOGRAMMETRY DEVICES IN FIELD RESEARCH

Polycam is a mobile application that creates 3D models of objects using high-resolution photogrammetry or LiDAR (Light Detection and Ranging). LiDAR scanning is available on Apple devices ending in “Pro” such as the iPhone 12 Pro or the iPad Pro. This project investigates the accuracy of photogrammetry scans versus LiDAR scans. Testing was conducted on measured geologic outcrops in the Hiawatha National Forest, located in the Upper Peninsula of Michigan, and at an abandoned quarry in Fort Smith, Arkansas. Photogrammetry and LiDAR scans were taken every one meter from the outcrops up to a total distance of five meters. The internal measuring system within Polycam was used to measure the geologic sections at each scan. The Polycam measurements were then compared to the physical measurements to identify the accuracy at varying scanning distances.

LiDAR camera scans were conducted with an iPad Pro, 12.9- inch (5th generation). An iPhone 12 was used for the optical camera photogrammetry scans. Field testing showed LiDAR equipped devices captured more accurate images. Optical cameras were most efficient in producing detailed scans at the micro-scale. The accuracy for LiDAR at the one-meter scanning distance was within 2.5-centimeter resolution, comparable to more expensive standalone LiDAR’s. However, the accuracy rapidly declined as the scanning distance increased from the outcrop.