This guide addresses common map stitching issues, including holes, motion blur, and distortion. It explains why these issues occur and provides actionable steps to resolve them.
Holes
Issue: Unstitched regions appear within an orthomosaic map or 3D model.
Resolution:
Ensure your data capture covers the entire region of interest.
Follow flight planning recommendations to minimize the possibility of holes.
Motion blur
Issue: Fast-moving drones or vibration can cause blur in imagery, indicating the shutter speed is not fast enough or the flight speed is too high.
Resolution:
Improve shutter speed.
Fly at a slower speed or higher altitude.
Unfocused camera
Issue: Similar to motion blur, an unfocused camera leads to overall poor quality and stitching failures.
Resolution:
Ensure autofocus is turned on.
Check that the lens is free of dust or particles.
Manually adjust camera settings in the DJI GO or DJI Fly app if necessary.
Vignetting on images
Issue: Vignetting appears as dark corners in images, often caused by a lack of light or obstructions during capture.
Resolution:
Re-fly the mission with less cloud cover to improve lighting.
Check the lens for dust or particles.
Insufficient image overlap
Issue: Low image overlap can cause holes or distortion because the software lacks sufficient data points to stitch images together.
Resolution:
Increase overlap settings in Advanced Settings within your flight plan.
Fly at a higher altitude to produce greater map detail over a smaller total space.
Non-nadir photos
Issue: Photos taken during turns or at horizontal angles include the horizon. This distorts the internal distance of the map because the software attempts to stitch distant areas rather than the immediate area of interest.
Resolution:
Capture images at an oblique (45-degree) or nadir (90-degree top-down) angle.
Avoid including the horizon in your dataset.
Images captured at low altitude
Issue: Low-altitude flights reduce the surface area (overlap) per image, making stitching difficult and potentially resulting in blurry maps.
Resolution:
Increase your altitude and overlap settings within your flight plan.
Note: Always obey your local and national altitude restriction regulations.
Homogenous imagery
Issue: Areas with little variation, such as fields with full crop cover or large bodies of water, are difficult to stitch because there are few unique features to connect.
Resolution:
Use an ND (Neutral Density) filter when flying over homogeneous areas.
Fly when the sun is not directly overhead to create shadows that break up the visual pattern.
Fly at a higher altitude to allow the camera to capture more unique features in each image.
Over-exposed or generally colorless features
Issue: Stitching relies on connecting similar points like a puzzle. Over-exposed images, snow cover, reflective roofs, or solid-white objects lack the visual data needed for successful connection.
Resolution:
Adjust camera settings to prevent over-exposure.
Avoid mapping during times of intense, direct sunlight on reflective surfaces.
V2.2