Global Shutter vs Rolling Shutter: What’s the difference and Why does it matter?
Updated: Sep 19, 2022
Photo by Fidel Fernando
With every new computing platform, a wave of new applications are enabled. Mainframe computers enabled scientific computing. Desktop computers enabled personal computing and smartphones continue to enable computing on-the-go. The same is true for the drone industry - where flying computers & sensors have started to enable a number of different applications. From asset inspections, search and rescue to site mapping and 3D modelling, the possibilities are endless and continue to grow with every passing day!
However, every drone application presents its own unique challenges and it’s important to choose the right drone hardware for the right job to get optimal results.
In this article, we’ll explore the main difference between Global Mechanical and Rolling Electronic Shutters found on modern commercial drones and understand which applications they are best suited for.
What is a Camera Shutter?
Before we jump into global vs rolling shutters, let’s understand what a camera shutter is.
“In photography, a shutter is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene.” (Source: Wikipedia)
So, in a nutshell, shutters are like light-policemen responsible for letting light through to a camera’s sensor!
Global Mechanical Shutter
A global mechanical shutter, as the name implies, is a mechanical part of the camera that opens and closes at the pre-defined shutter speed. Global shutters ensure that each image on the image sensor is exposed to light at exactly the same time.
This means that global shutters are inherently good at capturing subjects in the scene which are flying fast since all pixels on the camera are exposed to light exactly at the same time. This is also true if the scene is static and the camera is moving instead. (Hint: camera mounted on Drone Platforms)
Since many drone applications require the drone to capture images while moving (photogrammetry for instance), global mechanical shutters tend to perform better for these applications.
Rolling Electronic Shutter
A rolling electronic shutter, on the other hand, is a non-mechanical (electronic) shutter that exposes pixels on the image sensor in a line-by-line order. This means that a rolling shutter is not as good at capturing fast moving subjects or being used on a moving platform such as a commercial drone. However, since the rolling shutter is electronic (non-mechanical) in nature, they have less chances of mechanical failure.
One solution for using rolling shutters in drone applications is to make the drone stop before taking pictures or images. This can be easily achieved by using the Inspection modes in our mission planning software - Hammer Missions.
Global vs Rolling Shutter
So to sum up, cameras with global and rolling shutters both have their place in drone applications, but it helps to know the difference.
All pixels at the same time
Pixels in a line-by-line order
Photogrammetry (Moving Images) Applications And Capturing fast moving subjects
Inspection (Still Images) Applications And Less Prone to Mechanical Failure.
DJI Phantom Series
DJI Mavic Series
DJI Mavic vs Phantom
It’s important to mention here that your choice of drone platforms should not be singularly based on whether or not the platform support a global mechanical shutter. The DJI Mavic series for instance does not support a global mechanical shutter but incorporates a foldable body design, making it a lot more compatible than its Phantom cousins.
As with any drone application, it’s important to take the full picture into account - your goals and objectives before deciding and investing in a drone platform. If you'd like to learn more about how to high-quality data and get the most out of your drone missions, please feel free to visit our learning resources.
We hope this guide helped you build a better understanding of global vs rolling shutters on commercial drone cameras, and when to use one over the other.
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— The Hammer Team