the moving objects observed; Physiological factors such as age and fatigue. All observer-related influence quantities are stochastic parameters, because not all humans perceive the effect of same light ripple in the same way. That is why perception of stroboscopic effect is always expressed with a certain probability. For light levels encountered in common applications and for moderate speeds of movement of objects (connected to speeds that can be made by humans), an average sensitivity curve has been derived based on perception studies. The average sensitivity curve for sinusoidal modulated light waveforms, also called the stroboscopic effect contrast threshold function, as a function of frequency f is as follows: The contrast threshold function is depicted in Figure 2. Stroboscopic effect becomes visible if the modulation frequency of the TLM is in the region between approximately 10 Hz to 2000 Hz and if the magnitude of the TLM exceeds a certain level. The contrast threshold function shows that at modulation frequencies near 100 Hz, stroboscopic effect will be visible at relatively low magnitudes of modulation. Although stroboscopic effect in theory is also visible in the frequency range below 100 Hz, in practice visibility of flicker will dominate over stroboscopic effect in the frequency range up to 60 Hz. Moreover, large magnitudes of intentional repetitive TLMs with frequencies below 100 Hz are unlikely to occur in practice because residual TLMs generally occur at modulation frequencies that are twice the mains frequency (100 Hz or 120 Hz). Detailed explanations on the visibility of stroboscopic effect and other temporal light artefacts are also given in CIE TN 006:2016 and in a recorded webinar “Is it all just flicker?”. Objective assessment of stroboscopic effect Stroboscopic effect visibility meter For objective assessment of stroboscopic effect the stroboscopic effect visibility measure (SVM) has been developed. The specification of the stroboscopic effect visibility meter and the test method for objective assessment of lighting equipment is published in IEC technical report IEC TR 63158. SVM is calculated using the following summation formula: where Cm is the relative amplitude of the m-th Fourier component (trigonometric Fourier series representation) of the relative illuminance (relative to the DC-level); Tm is the stroboscopic effect contrast threshold function for visibility of stroboscopic effect of a sine wave at the frequency of the m-th Fourier component (see ). SVM can be used for objective assessment by a human observer of visible stroboscopic effects of temporal light