Photogrammetric processing of a shaded valley floor

[SteveBCH]

I need to use my DJI Phantom 4 RTK to fly and photograph the floor of a narrow valley that is fully shaded until about 9am or so. I'll prepare a photogrammetric point cloud using 3DSurvey for image processing. There are tall trees and the shadows are getting rather long these days even at high noon. Overcast days to get photo coverage of shadow areas are infrequent so wondering if, with the P4 camera set to "Cloudy", is there enough light in the shaded valley, before the sun crests the ridge, to get photos bright enough for photogrammetric processing? Anyone experimented with that? Thanks.

 

[Dave Pitman]

The "cloudy" option just affects white balance. For low light, you need a slow shutter speed, and correspondingly, a slow flight speed in order to not have image blur.

 

[SteveBCH]

The "cloudy" option just affects white balance. For low light, you need a slow shutter speed, and correspondingly, a slow flight speed in order to not have image blur.

Got it. Thanks!!

 

[adm_geomatics]

I'll add to @Dave Pitman 's great advice in that this would be one of those times appropriate for image editing. I use ACDSee to batch correct image exposure while maintaining the geotags containing the RTK geotags and accuracy properties. I have seen some clouds increase by up to 20% just by regaining detail in harsh shadows and blowout.

 

[SteveBCH]

I'll add to @Dave Pitman 's great advice in that this would be one of those times appropriate for image editing. I use ACDSee to batch correct image exposure while maintaining the geotags containing the RTK geotags and accuracy properties. I have seen some clouds increase by up to 20% just by regaining detail in harsh shadows and blowout.

Interesting. I'll look into that. Thanks!