Examples of Common Issues
There are a few common issues that cause low quality maps. Learn how to recognize and prevent these issues here:
Motion Blur
This is caused by fast-moving drones or vibration- this either means the shutter speed isn’t fast enough, or that you are flying too fast. The best way to solve this is to improve shutter speed, but flying slower or higher will help as well. Here is an example of what motion blur looks like:
Notice the distortion in the bottom right corner of the field.
Unfocused Cameras
Similar looking to motion blur, poor imagery may be due to an unfocused camera. Most cameras operate better if they are set to manual and focused to infinity before takeoff. Some autofocus programs take too long to adjust the setting and the photo is delayed.
Vignetting Images
Vignetting is caused by a lack of light. Re-flying the mission with less cloud cover can help with this. Check the lens for dust or particles that may be causing the dark images. The dark corners of this picture is evidence of vignetting.
Insufficient image overlap
The higher the image overlap, the easier it is for the software to process your image. High overlap gives you greater map detail over a smaller total space. The amount of overlap between photos will affect the map quality and size.
Non-nadir Photos
By including the horizon, the internal distance of the map will be distorted. The software will try to include the areas far away in stitching rather than the area of interest immediately below. Don’t use any photos which have sky in the photos.
Photos taken at low altitude
Taking photos at a low altitude lowers the surface area per image, which will make them difficult to stitch together. This can result in blurry maps. It is difficult to cover as much ground in one flight as you could from a higher altitude. Make sure to always obey your local/national altitude restriction regulations.
Homogenous imagery
A great example of homogenous imagery is a field with full crop cover. Because there is little variation or distinguishable features, and a tendency to have hard-to-determine patterns, it can be difficult to stitch together the images. The same attributes can apply to fields with full crop cover as well. It is especially problematic if it is windy which moves the plants from photo to photo. The anomaly of homogeneous imagery affects all image processing software. It’s just that difficult for computers to process.