Point Grey Flea3 GigE Technical Reference
7 Image Acquisition
7.2
External Trigger Timing
The time from the external trigger firing to the start of shutter is shown below:
1. Trigger Pulse
2. Propagation Delay
3. Exposure Time
4. Sensor Readout
5. Data Transfer
Figure 7.9: External trigger timing characteristics
It is possible for users to measure this themselves by configuring one of the camera’s GPIO pins to output a strobe pulse
(see
Programmable Strobe Output
) and connecting an oscilliscope up to the input trigger pin and the output strobe pin.
The camera will strobe each time an image acquisition is triggered; the start of the strobe pulse represents the start of
exposure.
7.3
Camera Behavior Between Triggers
When operating in external trigger mode, the camera clears charges from the sensor at the horizontal pixel clock rate
determined by the current frame rate. For example, if the camera is set to 10 FPS, charges are cleared off the sensor at
a horizontal pixel clock rate of 15 KHz. This action takes place following shutter integration, until the next trigger is
received. At that point, the horizontal clearing operation is aborted, and a final clearing of the entire sensor is
performed prior to shutter integration and transmission.
Revised 10/29/2013
Copyright ©2010-2013 Point Grey Research Inc.
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