Point Grey Flea3 GigE Technical Reference
7 Image Acquisition
7.1.8
Overlapped Exposure Readout Trigger (Mode 14)
Trigger Mode 14 is a vendor-unique trigger mode that is very similar to Trigger Mode 0, but allows for triggering at faster
frame rates. This mode works well for users who want to drive exposure start with an external event. However, users
who need a precise exposure start should use Trigger Mode 0.
In the figure below, the trigger may be overlapped with the readout of the image, similar to continuous shot (free-
running) mode. If the trigger arrives after readout is complete, it will start as quickly as the imaging area can be cleared.
If the trigger arrives before the end of shutter integration (that is, before the trigger is
armed
), it is dropped. If the
trigger arrives while the image is still being read out of the sensor, the start of exposure will be delayed until the next
opportunity to clear the imaging area without injecting noise into the output image. The end of exposure cannot occur
before the end of the previous image readout. Therefore, exposure start may be delayed to ensure this, which means
priority is given to maintaining the proper exposure time instead of to the trigger start.
Figure 7.7: Trigger Mode 14 (“Overlapped Exposure/Readout Mode”)
Registers—
TRIGGER_MODE: 830h
Presence
[0]
1
ON
[6]
1
Polarity
[7]
Low/High
Source
[8-10]
GPIO Pin
Value
[11]
Low/High
Mode
[12-15]
Trigger_Mode_14
Parameter
[20-31]
None
Revised 10/29/2013
Copyright ©2010-2013 Point Grey Research Inc.
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