Agisoft Metashape

Agisoft Metashape => General => Topic started by: ihb on April 08, 2019, 08:19:15 PM

Title: Advice Needed: Digital Elevation Model generation using MicaSense RedEdge MX
Post by: ihb on April 08, 2019, 08:19:15 PM
Hello everybody,

I am doing some research using small unmanned aircraft systems (DJI Matrice 200) fitted with a Micasense RedEdge MX multispectral camera (this is the only camera able to fit on the aircraft). One of my research goals involves generating a Digital Elevation Model (DEM) to look at crop height. The crop (grain sorghum - Sorghum bicolor) will be about 10-15 cm tall when the flight is to be flown. The camera resolution that Micasense provides is 8 cm/pixel at an altitude of 120m.

My question is this: Do any of you have any advice on how to build accurate DEMs using drones and the Micasense camera? I will be using Agisoft Photoscan Pro (1.5.2) for image processing. I have built DEMs before, but because i was not concerned with the crop height, I didn't check to see how accurate they were (in comparison with ground-truthed crop height). What kinds of equipment/calibration procedures do I need to use? I already plan to put out ground targets and collect RTK points on them.

One other thing: Crop height will be determined by subtracting the DEM from the digital terrain model (DTM), which will be collected with a flight before the crop emerges; the DTM will serve as a "base" from which to determine crop height from later flights.

Any advice is appreciated. Thanks!