In this paper, we review the LED flicker metrics as defined by the IEEE P2020 working group. The goal of these metrics is to quantify the flicker behaviour of a camera system, to enable engineers to quantify flicker mitigation, and to identify and explore challenging flicker use cases and system limitations. In brief, Flicker Modulation Index quantifies the modulation of a flickering light source, and is particularly useful for quantifying banding effects in rolling shutter cameras. Flicker Detection Index quantifies the ability of a camera system to distinguish a flickering light source from the background signal level. Modulation Mitigation Probably quantifies the ability of a camera system to mitigate modulation of a flickering light source. This paper explores various use cases of flicker, how the IEEE P2020 metrics can be used to quantify camera system performance in these use cases, and discusses measurement and reporting considerations for lab based flicker assessment.
The IEEE P2020 standard addresses fundamental image quality attributes that are specifically relevant to cameras in automotive imaging systems. The Noise standard in IEEE P2020 is mostly based on existing standards on noise in digital cameras. However, it adjusts test conditions and procedures to make them more suitable for cameras for automotive applications, such as use of fisheye lenses, 16-32 bit data format in operation in high dynamic range (HDR) mode, HDR scenes, extended temperature range, and near-infrared imaging. The work presents methodology, procedures and experimental results that demonstrate extraction of camera characteristics from videos of HDR and other test charts that are recorded in raw format, including dark and photo signals, temporal noise, fixed-pattern noise, signal-to-noise ratio curves, photon transfer curve, transaction factor and effective full well capacity. The work also presents methodology and experimental results for characterization of camera noise in the dark array and signal falloff.