Imaging systems with dynamic shutter operation

摘要

An imaging system may include an image sensor having an array of image pixels. Each image pixel may include an electronic shutter for controlling when a photosensor in the image pixel accumulates charge. The electronic shutter may be operable in an open state during which charge is allowed to accumulate on the photosensor and a closed state during which charge is drained from the photosensor. The electronic shutter may be cycled through multiple open and closed states during an image frame capture. At the end of each open state, the charge that has been acquired on the photosensor may be transferred from the photosensor to a pixel memory element. By breaking up the total exposure time for a pixel during an image frame into shorter, non-continuous periods of exposure time, dynamic scenery image artifacts may be minimized while maintaining the desired total exposure time.

主权项

1. A method for capturing image data with first and second image pixels during an image frame, wherein the first image pixel comprises a photosensor, a power supply terminal, a first transistor coupled between the power supply terminal and the photosensor, a charge storage region, a charge readout circuit coupled between the charge storage region and an output line, and a second transistor coupled between the photosensor and the charge storage region, the method comprising:
with the photosensor in the first image pixel, accumulating a first amount of charge over a first exposure time, wherein the first exposure time is non-continuous and comprises multiple integration periods that are each shorter than the first exposure time, wherein the integration periods are separated by non-integration periods; prior to each integration period, resetting the photosensor using the first transistor; at the end of each integration period, transferring a portion of the first amount of charge from the photosensor to the charge storage region using the second transistor; asserting the first transistor during each non-integration period, wherein charge is drained from the photosensor when the first transistor is asserted; and with the second image pixel, accumulating a second amount of charge over a second exposure time, wherein the second exposure time is continuous and overlaps the integration periods and non-integration periods of the first image pixel.