When choosing the right drone for your surveying needs, one of the most important features is also (ironically) hard to see: the camera shutter. The shutter style in a drone’s camera can directly impact survey accuracy, influencing the quality of the 3D models, maps, and measurements it generates.
At Propeller, we highly recommend using a drone camera with a “global” or “mechanical” shutter for the best results. Not all drones have this specialized hardware, but it’s critical for capturing undistorted images that yield precise models.
Read on to learn the differences between the two types of shutters (global vs. rolling), why we recommend one over the other, and the impact your shutter can have on your survey results.
What is a shutter, and why does it matter?
In photography, a camera’s shutter type determines how the sensor is exposed to light when taking a picture. There are two main shutter types: global (or the similarly functioning “mechanical” shutter) and rolling (commonly referred to as “electronic”). Each functions differently, with downstream effects on image quality—particularly when the drone is in motion.
Capturing precise imagery is essential for high-quality survey data because even slight distortions can impact reliability. Good data in equals good data out, so we recommend using the highest image quality to build 3D models that accurately reflect your reality.
Here’s how both shutter types work.
Global (or mechanical) shutter: Instant data capture
A global shutter captures an entire image simultaneously, exposing the entire sensor to light at once and ensuring undistorted images even while the drone is in motion. This “snapshot” effect is ideal for drone surveying because it minimizes image distortions caused by movement.
Instant image capture makes global shutters the preferred choice for any aerial survey that requires high accuracy. Clear images translate to more reliable 3D models and measurements, making it easier to achieve the accuracy standards many projects demand.
Global shutter pros and cons:
Pros
- Eliminates motion distortion: By capturing the entire frame at once, global shutters prevent the skewing effects that can arise with rolling shutters
- High accuracy: The lack of distortion ensures that images accurately reflect reality, which is crucial for precise mapping
- More reliable data: Global shutters capture clearer images, so they don’t require as much post-processing correction to account for distortion
Cons
- Size and weight: Global shutters are heavier and more expensive to manufacture than their electronic counterparts, so not all drones are designed to include them. However, as pricing comes down, we are seeing true global shutters included in platform designs
Rolling (electronic) shutter: Gradual exposure
Under most conditions, rolling shutters can’t produce the same data quality as a global shutter system. Rolling shutters capture an image sequentially, row by row, rather than exposing all pixels at once. Because parts of the image are exposed at slightly different times, rolling shutters present a challenge for survey-grade accuracy.
When a drone moves while using a rolling shutter, the sequential exposure can create a delay between rows, leading to a warped image effect known as rolling shutter distortion.
In practical terms, if the drone or the subject moves while capturing the image, objects can appear skewed, leaning, or distorted by unwanted motion blur in the final image. Though post-processing can correct some of these distortions, those corrections aren’t always perfect, which can compromise the final accuracy of the model.
Rolling shutter pros and cons:
Pros
- Lightweight: Electronic shutters have fewer parts, so they’re lightweight and useable on drones with smaller payloads.
- Low-cost: Because they cost less to produce, electronic shutters are also less expensive than global shutters.
Cons
- Image distortion: Sequential exposure causes distortion when the camera is in motion, negatively impacting accuracy.
- Lower data quality: These distortions make it harder to achieve high accuracy, which is critical for building survey-grade 3D terrain models.
- Imperfect post-processing: While processing can compensate for some of the image distortion, it generally falls short of the precision offered by global shutters.
Why we recommend global shutters
Both global and rolling shutters are common in the current drone market, but understanding their differences (and limitations) is key to selecting the right equipment.
Flying a survey drone with a rolling shutter can make it challenging to consistently achieve the high accuracy that many projects demand. While our post-processing workflows can partially correct rolling shutter distortion, these corrections often still fall short of the accuracy made possible by a global shutter.
For high accuracy and photorealistic terrain models, we highly recommend using drones with global or mechanical shutters. Healthy data inputs yield accurate data outputs you can use to track progress, keep workers safe, and make better project decisions at every step.
Want to learn more about how to choose the best drone for your worksite? Contact our team today.
