177

My video picture always has a stripy pattern in the background. What can I do about it?

This effect is caused by an unstable or inadequately stabilised light source. The light “flickers” at a frequency of 50 or 100 Hz. These quick changes of light are not visible to the human eye, but they do interfere with video recordings. This results in disturbance, particularly when the number of images per second is low (under 30 images per second). Depending on the image frequency of the video camera there is also another stripe pattern. The automatic colour correction or the white balance of the video camera can further heighten this effect.

Possible solutions:
• Reduction in the intensity of the lighting (the stabilisation electronics work better with low power output)
• Activation of the “cancel flicker” mode (camera properties in the driver settings)
• Choice of a higher video camera recording frequency
• Deactivation of the automatic colour correction and the white balance
• Use of a microscope with a stabilised power supply
• Use of an externally stabilised source of light (e.g. light coupled in through a mirror)

Microscope lighting not stabilised

Very well stabilised