Time‐Domain Analysis for Periodic and Aperiodic Display Flicker in Variable Refresh Rate Displays

ABSTRACT State‐of‐the‐art displays are emerging with a technology called variable refresh rate (VRR) that supports a wider range of refresh rates, both above and below 60 Hz. While VRR can reduce power consumption, it can cause flicker issues for users when the refresh rate is lowered below 60 Hz or when the refresh rate is changed even above 60 Hz. Since users can perceive both types of flicker as similar image artifacts, we developed the integrated flicker index to predict them. We introduced time‐domain analysis using impulse response functions (IRFs) to capture the onset of aperiodic luminance fluctuations in the VRR waveform and interpret human response to these fluctuations. In addition, based on the previous studies that display characteristics (e.g., luminance and size) affect flicker experience, we need to incorporate both effects of brightness and size into IRF. For this purpose, we utilized the converted IRFs from the TCSF model, which can explain these two effects. To validate the integrated flicker index, we conducted three experiments: flicker when the refresh rate is reduced below 60 Hz flicker (Exp1 and 2) and VRR flicker when the refresh rate is changed (Exp3). The results demonstrate that IRF converted from the appropriate TCSF could offer a more accurate prediction of flicker experience of VRR displays.