All pixels across the entire image sensor perform a global reset at the exact same moment, clearing all existing charge stored in each pixel to get ready for subsequent exposure.

• Every pixel on the sensor initiates exposure simultaneously and terminates exposure at the identical time. All pixel rows share the same exposure start time, end time and exposure duration. After exposure is cut off, no additional light can enter the pixels during the readout phase.

• Once exposure finishes, pixel data is read out row by row from top to bottom until the full frame is completely captured.

The first row undergoes circuit reset to empty residual charge, then starts exposure with a preset exposure time. Upon exposure completion, pixel data of Row 1 is read out.

• Right after Row 1 begins exposure, Row 2 carries out circuit reset and enters exposure with the same exposure duration as Row 1. Note that the exposure periods of Row 1 and Row 2 partially overlap. Readout for Row 2 is executed once its exposure ends.

•This sequential operation applies to all subsequent rows. Each row runs circuit reset right when the previous row starts exposure, and every row maintains identical exposure length.

• As a result, though all rows feature equal exposure time, their exposure start and end timestamps are staggered.

Core Conclusion

When capturing fast-moving objects:A global shutter synchronizes exposure timing and duration for the whole frame, locking the position of moving objects for every sensor row during exposure. It precisely freezes and restores instantaneous details of high-speed subjects, making it ideal for snapshot photography of moving targets.By contrast, a rolling shutter applies the same exposure length to each row but shifts exposure timestamps line by line. When the target moves rapidly, the object will be in a different spatial position during exposure for each row. This leads to geometric distortion (the jelly effect) in footage, so rolling shutter is not suitable for shooting objects in high-speed motion.

Global shutter was widely adopted in early CCD image sensors, while it was rarely seen in conventional CMOS sensors, which predominantly adopt rolling shutter technology as the mainstream exposure scheme.