Many lamps and displays in our daily environment do not emit completely stable light. Instead, their light output varies, sometimes strongly, and often with frequencies far above those visible to the Human eye.
Such “flicker” can cause headaches and is distracting. For people who are sensitive or suffer from epilepsy, it can even result in seizures.
For this reason, various ways have been created to measure and assess the severity of flicker.
Measuring Values
Usually, Flicker is measured by recording a short sample of a lamp or display emitting light. In most cases, the frequencies of the signal are analyzed (Fourier Transformation) and the dominant frequency is determined.
Afterwards, various values to assess the flicker severity are calculated. These can be rather simple, like “Percentage Flicker”, “Flicker Index” and “Flicker Contrast”. But there are also more complex measurements and calculations like “SVM” and “PstLM”.
