I generated imagery from a low flying drone (40 M AGL) equipped with a mica sense RedEdge multi-spectral camera and have processed the imagery in PIX4D and now am attempting to do some analysis in QGIS.
I am working to create CHM for several research plots and am noticing that the minimum height in DTMs generated from imagery on the same plot differ by about up to 2 meters. This is a big difference and will drastically skew results. Some of the plant heights are below 2 meters.
Any idea on how to generate a highly accurate DTM that can be used in CHM analysis?
I do have imagery from winter months and have considered generating a DTM from the leafless season but wonder about differences in ground level due to frost heaving and changes due to erosion. Any one have experience with canopy height modelling?