Instruction manual

Guppy Technical ManualV7.4.0
143
Controlling image capture
Electronic rolling shutter (ERS) and global reset
release shutter (GRR) (only Guppy F-503)
The CMOS Guppy F-503 (Micron/Aptina CMOS sensor MT9P031) has an electronic
rolling shutter (ERS) and a global reset release shutter (GRR) but no global
shutter.
Shutter mode Guppy F-503 Description
Electronic rolling shutter (ERS) Advantage: designed for maximum frame rates
How it works:
• exposure time is the same for all rows
• start of exposure is different for each row
 This can cause a shear in moving objects, see photo below.
Customer action: Use this mode only in situations with non-
moving objects.
Global reset release shutter (GRR) Advantage: designed for situations with moving objects; use this
mode to avoid the problems with ERS described above
How it works: Image acquisition is done by starting all rows
exposures at the same time.
 So there is no shear in moving objects.
• exposure time is different for each row
• start of exposure is the same for each row
Customer action: Different exposure time for each row will result
in images which get brighter with each row (see photo below
left). In order to get an image with uniform illumination, use
special lighting (flash) or mechanical/LCD extra shutter (see
photo below right) which will stop the exposure of all rows
simultaneously.
Table 52: Guppy F-503 shutter modes
frame time
exposure time
exposure time different for each row
T
row
exposure time row1