The “flicker phenomenon” refers to a phenomenon in which abnormalities such as “light and dark fluctuations” and “color tone shifts” appear in images captured by a camera, although they cannot be detected with the naked eye.
In this article, we will introduce “What is the Flicker Phenomenon” and “How to Mitigate the Flicker Phenomenon”.
The flicker phenomenon is
Some lighting devices flash to match the power frequency, while others pulse as a dimming system.
Although the flashing of light cannot be felt with the naked eye, if the shutter speed of the camera is faster than the blinking cycle, abnormalities such as “light and dark fluctuations” and “color tone shifts” will occur in the captured image. This is the flicker phenomenon.
The flicker phenomenon occurs under lighting such as fluorescent lamps that emit periodic light, and does not occur under direct current lighting.
There are two main symptoms of flicker.
In a camera with a global shutter system, the entire image periodically repeats fluctuations in brightness.
On the other hand, with a rolling shutter camera, horizontal stripes may appear in the footage, which may appear to flow vertically.
< Flicker Phenomenon: Horizontal Stripes of Light and Dark in Rolling Shutter Cameras>
How to prevent flicker phenomenon
Basically, there are only three ways.
1. Use a direct current lighting system.
2. Set the shutter speed to be slower than the blinking speed.
3. Use a camera equipped with a “flicker-free function”.
1. Use a direct current lighting device.
It occurs under lighting that repeatedly emits periodic light, and does not occur in lighting with direct current lighting.
2. Set the shutter speed to be slower than the blinking speed.
The flicker phenomenon can be suppressed to some extent by adjusting the camera’s exposure time or shutter speed, but it cannot be completely eliminated. Even if the flicker seems to disappear, the light and dark are changing over a long period of tens of seconds or more. Especially when using a high-speed camera under fluorescent lighting, a significant flicker phenomenon occurs.
※ If the shutter speed cannot be adjusted on the camera side, the aperture of the lens can be adjusted to compensate for the lack of illumination with DC lighting to reduce the effect of pulse lighting relatively.
3. Use a camera equipped with a “flicker-free function”.
The “flicker-free function” is a function in which the camera automatically detects the flashing of the light source and releases the shutter at a timing that has little effect on the brightness and color tone.
To avoid the flicker phenomenon, use direct current lighting or strobe lighting synchronized with the camera shutter for high-speed camera lighting.
We offer a wide range of high-speed cameras and lighting equipment suitable for those applications, such as high-speed camera lighting and strobe lighting.
If you are suffering from the flicker phenomenon, please feel free to contact us.
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