High dynamic range approach for a CMOS imager using a rolling shutter and a gated photocathode

摘要

An imaging system includes a photocathode, configured to be gated ON/OFF at a selected gating frequency, for converting photons from an object into electrons and selectively transmitting the electrons toward an imaging sensor. The imaging sensor is configured to receive the electrons and provide a rolling shutter read out of rows of pixels. The imaging sensor includes a variable well selectively set to charge the rows of pixels to a first intensity level during a first integration period and charge to a second intensity level during a second integration period. The second integration period is longer than an OFF time of the photocathode gating frequency. The first and second integration periods are equal to a frame duration of the imaging sensor, defining a number of frames per second, and the selected gating frequency of the photocathode is higher than the number of frames per second.