In this tutorial, we’re going to look at what motion blur is and how you can reduce motion blur in your captured imagery. We'll then take a look at how you can use Hammer to achieve this in practice.
Motion blur is the apparent streaking of moving objects in a photograph or a sequence of frames, such as a film or animation. It results when the image being recorded changes during the recording of a single exposure, due to rapid movement or long exposure. (Source: Wikipedia and Shutter Stock)
Motion Blur (left), No Motion Blur (right).
From a drone’s perspective, motion blur is caused when the drone’s flying too fast with respect to the shutter speed — causing the scene to substantially change over a single camera exposure.
Whilst it’s difficult to completely eliminate motion blur during a mapping/3D modelling mission, it is possible to reduce it considerably for better post-processing results. But first let’s define motion blur better:
Motion Blur = Camera Shutter Interval(s) x Drone Speed(m/s).
(distance travelled by the drone’s camera over a single exposure)
As a general rule, your motion blur should not be greater than 1 x Ground Sampling Distance (GSD), where GSD is the distance on the ground for every 2 adjacent pixels in the image.
In the steps below, we outline how you can reduce motion blur in your flights using Hammer, but feel free to use any other drone app of your choice.
Plan a Mapping / 3D modelling mission in Hammer.
Create a Mapping / 3D modelling mission in Hammer.
Connect a Drone to Hammer.
Open the mini video screen by tapping on the camera icon.
Tap on the mini video screen to enter the video view.
Tap on the top right gear to open camera settings.
Adjust camera settings based on the lighting conditions.
Switch back to the original mapping settings. You’ll notice a motion blur calculator right next to the computed GSD.
Motion Blur Calculator in Hammer.
8. Note: If your motion blur is higher than 2x your mission’s GSD, Hammer will show the motion blur calculation in red as a warning.
9. To bring motion blur in the acceptable range, you can either:
Reduce motion blur by reducing flight speed or increasing shutter speed.
Increase your GSD by increasing your mission altitude.
10. If you would like to completely eliminate motion blur, we would recommend using the inspection mission in Hammer which makes the drone stop at every point before taking a picture.
We hope this guide was helpful. In short:
Motion Blur is the distance travelled by your camera during one exposure.
If this distance is too high, it can result in artefacts in your imagery.
You can reduce motion blur’s impact by ensuring it is less than 1 x GSD.
Connect a drone with Hammer to use the motion blur calculator.
If you’d like to learn more about Hammer could be used for your specific use-case or how to work with motion blur in your data sets, please do get in touch with us at firstname.lastname@example.org. We’d be happy to help!
— The Hammer Team
Hammer is available through the iOS App Store.
Thanks to EagleDrone NL for their feedback on a draft version of this post.