HIGH DYNAMIC RANGE APPROACH FOR CMOS IMAGING DEVICE USING ROLLING SHUTTER AND GATED PHOTOCATHODE

摘要

PROBLEM TO BE SOLVED: To increase the dynamic range of a CMOS imaging device when a rolling shutter is operated.

SOLUTION: An imaging system comprises a photocathode that is configured to be gated ON/OFF at a selected gating frequency, for converting lights 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 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 a gating frequency of the photocathode. The first and second integration periods are equal to a frame duration of the imaging sensor, defining the number of frames per second, and the selected gating frequency of the photocathode is higher than the number of frames per second.

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