MATRIX VISION - mvBlueFOX3 Technical Documentation
Detecting overtriggering

Scenario

The image acquisition of a camera consists of two steps:

  • exposure of the sensor and
  • readout of the sensor data

During these steps, a trigger signal will be skipped:

Figure 1: Trigger counter increases but the start exposure counter not

To notice overtriggering, you can use counters:

  • One counter counts the incoming trigger signals, the
  • second counter counts the ExposureStart signals.

Using the chunk data you can overlay the counters in the live image.

Setting the overtrigger detector using wxPropView

First of all, we have to set the trigger in "Setting -> Base -> Camera -> GenICam -> Acquisition Control" with following settings:

Property name wxPropView Setting
Trigger Selector FrameStart
Trigger Mode On
Trigger Source Line4
Trigger Activation RisingEdge
Exposure Mode Timed

This trigger will start an acquisition after a rising edge signal on line 4 (= DigIn0 ).

Now, set the two counters. Both counters (Counter1 and Counter2) will be reset and start after the acquisition (AcquisitionStart) has started.

While Counter1 increases with every ExposureStart event (see figure above for the event and acquisition details) ...

Figure 2: Setting Counter1

... Counter2 increases with every RisingEdge of the trigger signal:

Figure 3: Setting Counter2

Now, you can check if the trigger signal is skipped (when a rising edge signal is active during readout) or not by comparing the two counters.

Enable the inclusion of the selected chunk data ("Chunk Mode Active = 1") in the payload of the image in "Setting -> Base -> Camera -> GenICam -> Chunk Data Control":

Figure 4: Enable chunk data

Activate the info overlay in the display area. Right-click on the live display and select: "Request Info Overlay"

Figure 5: Show chunk data

The following figure shows that no trigger signal is skipped:

Figure 6: Trigger Signal counter equals ExposureStart counter

The following figure shows that the acquisition is overtriggered:

Figure 7: Trigger Signal counter is higher than ExposureStart counter