Global Shutter CMOS Vision Sensors and Event Cameras for On-Chip Dynamic Information

The on-chip extraction of dynamic information from a scene can be addressed with either frame-based CMOS vision, also called smart image sensors, or with dynamic vision sensors, also known as event cameras. When implemented with a pinned photodiode (PPD) as 4-transistor active pixel sensors (4T-APS) the former brings about the benefit of low temporal noise and dark current but without high dynamic range (HDR). The latter comes with the benefits of HDR and fast event detection rate at a low power consumption. The drawback is the background activity noise, which leads to additional hardware or algorithms to keep it low. In essence, the taxonomy of dynamic information extraction with image sensors is that of global shutter solutions and event cameras, each of which with their pros and cons. This paper digs in such differences and similarities focused on mismatch and noise through a global shutter 4T-APS implementation with local HDR incorporated in 180 nm CMOS technology vs conventional logarithmic event sensors found in the literature.