What does this equation mean?

where C is a contrast threshold set by an analog bias current, and each event carries just an address, a timestamp, and a sign — brighter or darker — streamed out asynchronously on a shared digital bus rather than assembled into frames. This architecture was demonstrated in a foundational 128×128-pixel silicon retina in 2008, which reported 120 dB of dynamic range and event latency down to 15 microseconds, figures that were startling next to the roughly 60–70 dB dynamic range and millisecond-scale exposure timing of conventional imagers of the era [ 1 ] . A comprehensive 2020 survey of the field puts the comparison plainly: event sensors commonly reach on the order of 140 dB of dynamic range against roughly 60 dB for standard frame sensors, alongside microsecond temporal resolution and, because output data volume tracks scene activity rather than pixel count times frame rate, substantially lower average data rate and power for scenes that are mostly static [ 2 ] .