- Stroboscopic Motion Definition: Stroboscopic motion is defined as a visual phenomenon where continuous rotational motion appears as separate short samples close to the motion’s period.
- Strobe Light Effect: The strobe light effect occurs when a moving object is illuminated by a fluctuating light source, causing it to appear as if it’s moving differently than it is.
- Examples of Stroboscopic Motion: A car wheel appears to move backward in a film due to stroboscopic motion.
- Safety Concerns: The stroboscopic effect can lead to headaches, annoyance, and decreased task performance.
- Reducing the Effect: Methods include using large capacitors or increasing current frequency in lighting, though these can increase cost and reduce efficiency.
What is Stroboscopic Motion?
Stroboscopic motion (also known as the Stroboscopic Effect) is defined as a visual phenomenon that occurs when continuous rotational motion is represented by a series of short samples (as opposed to a continuous view) at a sampling rate close to the period of the motion.
A common example of stroboscopic motion is a car wheel. When the car moves forward, the wheel can appear to move backward when viewed on film.
Stroboscopic Motion Example
For example, if an object rotates at 50 revolutions per second and we flash a light at the same rate, the object appears stationary because each flash shows it in the same position.
The same rotating object was observed at a flash rate of more than 50 revolutions per second. Let say the flash rate is 51 times per second. In this condition, the object illuminates slightly earlier part of its cycle. Therefore, it looks like the object is rotating in a backward direction.
Similarly, the object was observed at a flash rate of fewer than 50 revolutions per second. Let say the flash rate is 49 times per second. Each flash illuminates a slightly later part of its cycle. Hence, the object looks like rotating in a forward direction.
So, the rotating objects look running in the forward or backward direction either remains standstill due to the stroboscopic effect.
Strobe Light Effect
Stroboscopic effect is an unwanted effect that may become visible when a person observes a rotating or moving element illuminate by a time-modulated light source.
Modulated light comes from a fluctuating or dimming source, caused by light level regulation technology.
This effect causes an unwanted and unsafe situation in the workplace that leads to headaches, annoyance, and reduce task performance.
Strobe light effect appears in moving or running objects. Hence, this effect is also known as a wagon-wheel effect. In this effect, it seems the wheel move with different speed and direction that leads hazardous situation.
There is a tool that produces repetitive flashes of light known as a stroboscope.
Illumination of light from lighting source mat varying with respect to time. Sometimes, this effect is intentionally added to a lighting system. For example, it is used in stage lighting, traffic signals, warning lights, and signaling applications.
Temporal light modulations depend on the type of light source, frequency of main supply, driver technology. The stroboscopic effect in lights is often called a flicker.
Flicker is a directly visible effect at a low modulation frequency (below 80 Hz). But the stroboscopic effect is visible if light modulation is present with modulation frequencies.
Lighting equipment is designed to reduce modulation, but this can increase cost and size, and reduce lifespan and efficiency.
A large storage capacitor is used to reduce the modulation in current drive LEDs. But the use of capacitor results shorten life as the failure rate of a capacitor is highest among all components.
A second way to reduce modulation in LEDs is to increase current frequency. This solution also increases the overall size of the driver and reduces efficiency.
The stroboscopic effect is visible in the frequency range of 80 Hz to 2000 Hz.
