stroboskopeffekt

The stroboscope effect, also known as the wagon-wheel effect, is a visual phenomenon where a rapidly rotating or oscillating object appears to be moving slower, standing still, or even moving backward. This illusion occurs when the object is viewed under intermittent illumination, such as from a flashing light source or a camera recording at a specific frame rate.

The effect arises from the way our brain interprets visual information. When the flashing light occurs, our brain captures snapshots of the object's position. If the time between flashes is just right, the object's position in one snapshot can be very close to its position in the next snapshot, but slightly ahead or behind its actual motion. This discrepancy can lead to the perception of slower or reversed motion.

For example, a spinning wheel illuminated by a strobe light might appear to be rotating much slower than it actually is. If the strobe flashes at a rate that perfectly matches a multiple of the wheel's rotation speed, the wheel can even seem to be stationary. If the strobe flashes at a rate slightly off from a multiple, the wheel might appear to be rotating backward.

This effect is commonly observed in films and videos, where the frame rate of the camera acts as the intermittent illumination. It can also be seen with rotating machinery under flickering lights, or even with natural phenomena like waterfalls appearing to flow backward in certain video recordings. Understanding the stroboscope effect is important in fields like animation, filmmaking, and machine vision.