External Trigger Timing; Camera Behavior Between Triggers - FLIR GRASSHOPPER 3 Series Technical Reference

7.2

External Trigger Timing

The time from the external trigger firing to the start of shutter is shown below:
Depending on the firmware version, Sensor Readout (4) and Data Transfer (5) may occur concurrently.
It is possible for users to measure this themselves by configuring one of the camera's GPIO pins to output a
strobe pulse (see
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.
2/10/2017
©2013-2017
FLIR Integrated Imaging
Solutions Inc. All rights reserved.
Figure 7.7: External trigger timing characteristics
Programmable Strobe Output) and connecting an oscilliscope up to the input trigger pin and the
Grasshopper
Registers—TRIGGER_MODE: 830h
Value [11]
Mode [12-15]
Parameter [20-31]
®
3 PGE Technical Reference
7 Image Acquisition
Low/High
Trigger_Mode_15
N number of images to
be acquired
1. Trigger Pulse
2. Propagation
Delay
3. Exposure Time
4. Sensor Readout
5. Data Transfer
50