The high HDR performance is made possible by placing only back-illuminated pixels and a part of N-type MOS transistor on the pixel chip (top), thereby allowing the aperture ratio to be enhanced by up to 77%. High sensitivity/low noise technologies Sony has developed over many years of CMOS image sensor development enable event detection in low-light conditions down to 40mlx.
While a frame-based sensor outputs entire images at fixed intervals according to the frame rate, an event-based sensor selects pixel data asynchronously using a row selection arbiter circuit. By adding time information at 1μs precision to the pixel address where a change in luminance has occurred, event data readout is ensured with high time resolution. The companies say the chip supports an output event rate up to 1.066Gevents/s by efficiently compressing the event data, i.e. luminance change polarity, time, and x/y coordinate information for each event.
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