Rolling shutter effect on a propeller
When modern digital cameras with an array like sensor capture an image, the color information is mostly saved one line after each other. This means that there is a small amount of time between two consecutively scanned lines of an single image.
Imagine a fast moving object like the propeller of an aircraft beeing in the cameras field of view. What happens!?
While the scanning line is moving in some direction (e.g. left->right or up->down) the object moves and its shape will get distorted in the final image. You can find dozends of examples on the internet - just type "rolling shutter propeller" in your favourite search engine or click on the first link [1] below this text. Inspired from an article by Jason Cole which can be found in Link Nr. [2] or [3] I tried to recreate this phenomenon using intersection of lines and some other GeoGebra features. What you can see below is a parametric and completely interactive visualization of this "rolling shutter" effect, applied for a propeller with varying number of stick-like "blades".
You can vary every parameter and try to understand how it influences the final image. When you've done that you may want to:
- Select some "rolling shutter propeller" example from the internet and.
- Try to recreate the shape!
- Repeat the first two steps. Just for fun, as long as you like :)