Assessment of Image-Based Point Cloud Products to Generate a Bare Earth Surface and Estimate Canopy Heights in a Woodland Ecosystem

Remote Sensing

Jennifer L. R. Jensen¹  Adam J. Mathews²  Lars T. Waser³ 

[1]Department of Geography, Texas State University, 601 University Drive, San Marcos, TX 78666, USADepartment of Geography, Oklahoma State University, 337 Murray Hall, Stillwater, OK 78078, USA

[2]

[3]id="af1-remotesensing-08-00050">1Department of Geography, Texas State University, 601 University Drive, San Marcos, TX 78666, U

关键词: structure from motion;    image-based point cloud;    digital terrain model;    vegetation;    lidar;   

DOI  :  10.3390/rs8010050

来源: mdpi

【 摘 要 】

We examine the utility of Structure from Motion (SfM) point cloud products to generate a digital terrain model (DTM) and estimate canopy heights in a woodland ecosystem in the Texas Hill Country, USA. Very high spatial resolution images were acquired with a Canon PowerShot A800 digital camera mounted on an unmanned aerial system. Image mosaicking and dense point matching were accomplished using Agisoft PhotoScan. The resulting point cloud was classified according to ground/non-ground classes and used to interpolate a high resolution DTM which was both compared to a DTM from an existing lidar dataset and used to model vegetation height for fifteen 20 × 20 m plots. Differences in the interpolated DTM surfaces demonstrate that the SfM surface overestimates lidar-modeled ground height with a mean difference of 0.19 m and standard deviation of 0.66 m. Height estimates obtained solely from SfM products were successful with R² values of 0.91, 0.90, and 0.89 for mean, median, and maximum canopy height, respectively. Use of the lidar DTM in the analyses resulted in R² values of 0.90, 0.89, and 0.89 for mean, median, and maximum canopy height. Our results suggest that SfM-derived point cloud products function as well as lidar data for estimating vegetation canopy height for our specific study area.

【 授权许可】

CC BY   
© 2016 by the authors; licensee MDPI, Basel, Switzerland.