Troubleshooting

Some Areas of the DSM have a lot of Noise - PIX4dmapper

Error


Some areas of the DSM have a lot of noise. Instead of representing correctly the area, the DSM has rough distortions / noise.

Description

The Densified Point Cloud and consequently the DSM, which is created based on this, has a lot of noise on specific areas.

bad_DSM.jpg
Figure 1. Noise on the DSM.

Cause

This error comes from processing images with different light conditions. These images have different shades that confuse the algorithm and create noise.

bad_DSM_shades1.jpg
bad_DSM_shades2.jpg
Shadow
No Shadow
Figure 2. Different light condition between images.

Solution

In order to solve the issue, both the flight conditions and the processing need to be taken into consideration:

  • During flight: Try to fly with the same lighting conditions as much as possible, same hour of the day, same sun direction, same weather conditions etc.
  • During processing:
bad_DSM.jpg
bad_DSM_mtp.jpg
Before adding Manual Tie Points
After adding Manual Tie Points
Figure 3. Improvement of the DSM after adding Manual Tie Points.