I produced a DSM raster from LIDAR data for eastern Kentucky. There are strange lines from southwest to northeast. Do you have any idea what those might be? I generated the DSM raster with both first return and non ground classes but results were similar. I am using ArcMap 10.6. Basically I used first return or non ground classes and created DSM from elevation data by using LAS dataset to raster tool. Then subtracted DEM from it. DEM looks fine. I also created Canopy Density Model (CDM) by using LAS Point statistics as raster (points above surface/ all points). I still have the same issue with CDM. Red areas show zero value (ground) green areas are higher areas with structures or canopy. Here is the picture
They may be an artifact of imperfect calibration during (or after) data acquisition. The stripes look like they might be the field of view of the sensor as taken along a flight path. Possibly the thin, more reddish, lines are where these scans overlap.
If this is the case then simple post-processing options might include: a median filter and applying an offset. A fancier (but not necessarily better) approach might be to try and filter out frequencies in an FFT then inverting back to raster.
After taking a closer look to raster and lidar data, I figured greener (higher) data acquired when trees have leaves attached while more red data most likely collected in winter or very late fall. I concluded like this because there is no problem with structures or conifers. When the majority of land type is forest and leaves do not exist. Most of first return collected from ground and eventually marked with zero height value. Most likely, those red stripes are where the overlaps are which is caused by too many ground points. Thank you for your comments and help.