EVALUATING THE SPATIAL RESOLUTION OF SUAS SENSORS IN TWO AND THREE DIMENSIONS

Small unmanned aerial systems (sUAS) continue to proliferate and are frequently used across many different fields. Ease of use, low cost, and the availability of advanced processing and analytics have resulted in their use in many new remote sensing applications. With these new advancements it is prudent to evaluate sUAS data in a quantitative and objective manner to better understand its quality and utility. With the common use of Structure from Motion (SfM) tools to extract three-dimensional (3D) data from passive two-dimensional (2D) sUAS imagery, evaluating resolution in both two and three dimensions will help users understand the data and determine appropriate uses. Thoroughly understanding the performance of these systems and processes will ensure users have confidence in data collection and analytic results. The motivation for this analysis resulted from questions regarding the suitability of sUAS-derived 3D data in estimating vegetation height over the Pohakuloa Training Area on the island of Hawai'i. Serendipitous collection of an in situ high contrast edge target in the scene enabled both 2D and 3D resolution analyses that are presented in this paper. This resolution analysis centers on 2D and 3D implementations of the Edge Spread Function (ESF) and Line Spread Function (LSF) measurements on data collected by a Skydio X2D quadcopter. These measurements show a horizontal resolution of 4.87cm in 3D data derived from 1.12cm 2D GSD source imagery, a factor of degradation of more than four.