Pulsed Illumination Synchronization for Global Reset Rolling Shutter Imagers
Global Reset rolling shutter imagers eliminate motion blur when pulsed light fires strictly within the dark global integration window under controlled ambient light.
Global Reset
Simultaneous Initiation
An electronic trigger mechanism in active-pixel sensors starts the integration period of all photosensitive elements at the same instant. Implementing a global reset eliminates the line-by-line start delays that cause geometric skewing in rolling-shutter arrays. This simultaneous start ensures that all pixels capture light from the identical temporal window.
Operational Constraint
The concurrent cessation of exposure requires a mechanical shutter or a specialized storage node within each pixel to prevent continued accumulation of charges. Without these hardware structures, the sensor continues to register ambient light during the sequential readout phase. A global reset alone does not prevent rolling readout artifacts unless the illumination is pulsed or the sensor utilizes global shutter architecture.
This constraint limits the raw efficiency of the acquisition cycle when operating under continuous bright lighting conditions.
Temporal Contrast
Differences in exposure duration across the sensor surface occur when the readout process remains sequential after a synchronized start. This asymmetry generates an exposure gradient that compromises measurement repeatability across the sensor surface.
Metrological Application
Calibration routines for high-speed imaging systems rely on synchronized starts to establish accurate temporal baselines. Instruments using a global reset can measure transient phenomena with sub-millisecond precision. This temporal alignment is verified by checking the simultaneous start across all pixel coordinates using a calibrated strobe source.