Triggered Image Acquisition#

If the camera is configured for triggered image acquisition, you can trigger image captures at particular points in time.

Most modern imaging applications work with triggered image acquisition.

If you want to acquire images continuously without having to trigger acquisitions, see free run image acquisition.

Using the Feature#

Hardware and Software Triggering#

When the camera is configured for hardware triggering, the following can act as a trigger signal:

• An electrical signal applied to one of the camera's input lines (external hardware triggering)
• An internal signal generated by the camera, e.g., a timer or a counter signal (internal hardware triggering)

When the camera is configured for software triggering, a software command or signal acts as a trigger signal. The software command can be executed using the pylon API.

In terms of configuration, the only difference between hardware and software triggering is the trigger source. For hardware triggering, you must choose a hardware trigger source. For software triggering, you must choose a software trigger source.

Also, some configuration steps don't apply to software triggering, e.g., choosing a trigger activation mode.

Configuring Triggered Image Acquisition#

To configure triggered image acquisition:

1. Set the TriggerSelector parameter to select the type of trigger you want to configure.
2. Set the TriggerMode parameter to On to enable the trigger.
3. Configure the trigger:
   1. Set the TriggerSource parameter to define which signal triggers the trigger.
   2. If applicable, set the TriggerActivation parameter to define which signal transition triggers the trigger.
   3. If applicable, set the TriggerDelay parameter to define when the trigger is triggered.
4. Repeat the above steps for all triggers you want to configure.

Example 1: Basic Hardware Triggering#

Assume you want to configure the camera so that image acquisition starts whenever a rising signal on physical input line 1 is received.

To setup this image acquisition, set the parameter as follows:

TriggerSelector = FrameStart
TriggerMode = On
TriggerActivation = RisingEdge
TriggerSource = Line1

Example 2: Advanced Hardware Triggering#

Assume you want to configure the camera so that image exposure starts whenever a rising signal on physical input line 1 is received, and stops whenever a falling signal on line 2 is received.

ExposureMode = TriggerControlled

TriggerSelector = ExposureStart
TriggerMode = On
TriggerActivation = RisingEdge
TriggerSource = Line1

TriggerSelector = ExposureEnd
TriggerMode = On
TriggerActivation = FallingEdge
TriggerSource = Line2

Example 3: Software Triggering#

Assume you want to configure the camera so that image acquisition starts whenever a software command is received.

TriggerSelector = FrameStart
TriggerMode = On
TriggerSource = Software

Now, executing the TriggerSoftware command via the pylon API starts image acquisition.

Example 4: Triggering a Series of Images#

Assume you want to trigger the acquisition of a series of images with only one trigger signal.

TriggerSelector = FrameBurstStart
TriggerMode = On
AcquisitionBurstFrameCount = 3
TriggerActivation = RisingEdge
TriggerSource = Line1

Now, whenever a rising signal on physical input line 1 is received, the camera automatically acquires a complete series of 3 images.

Trigger Types#

You can set the trigger type using the TriggerSelector parameter.

This selects which trigger can be configured. For example, you can select the Exposure Start trigger to configure when and how the camera should start exposing.

Depending on your camera model, the following trigger types are available:

• FrameStart
• FrameEnd
• FrameActive
• FrameBurstStart
• FrameBurstEnd
• FrameBurstActive
• ExposureStart
• ExposureEnd
• ExposureActive
• LineStart

Frame Burst Triggers#

If available, you can use the Frame Burst Start, End, and Active triggers to control the acquisition of a series of images (a "burst" of images).

The number of images per series is specified by the AcquisitionBurstFrameCount parameter. The maximum number of images per series is 255 on ace classic/U/L cameras and 1023 on other cameras.

By default, these triggers are disabled, and the camera acquires single images only.

If you enable these triggers and the camera receives the corresponding signal via the trigger source configured, the following happens:

• Frame Burst Start: The camera initializes the acquisition of a series of images.
  If the Frame Start trigger is enabled, the camera is now ready to receive Frame Start trigger signals.
  If the Frame Start trigger is disabled and the Exposure Start trigger is enabled, the camera automatically initializes the next image.
  If the Frame Start trigger is disabled and the Exposure Start trigger is also disabled or not available, the camera automatically acquires the entire series of images.
• Frame Burst End: The camera finalizes the acquisition of a series of images.
  If this trigger is disabled or not available, the camera automatically finalizes the series after the last image acquisition.
• Frame Burst Active: When the trigger signal rises, the camera generates a Frame Burst Start trigger signal. When the trigger signal falls, the camera generates a Frame Burst End trigger signal. You can change this behavior by setting the trigger activation mode.

Frame and Line Triggers#

If available, you can use the Frame Start, End, and Active triggers or the Line Start trigger to control the acquisition of a single image. These are the trigger types used most commonly. In most image applications, you will only need to configure these trigger types.

By default, these triggers are disabled, and the camera controls image acquisition automatically.

If you enable these triggers and the camera receives the corresponding signal via the trigger source configured, the following happens:

• Frame Start: The camera initializes the acquisition of one image.
  If the Exposure Start trigger is enabled, the camera is now ready to receive Exposure Start trigger signals.
  If the Exposure Start trigger is not available or disabled, the camera automatically starts exposing the image. Note that in this case, exposure starts with a delay (see exposure start delay).
• Frame End: The camera finalizes the acquisition of one image.
  If this trigger is disabled or not available, the camera automatically finalizes image acquisition after exposure.
• Frame Active: When the trigger signal rises, the camera generates a Frame Start trigger signal. When the trigger signal falls, the camera generates a Frame End trigger signal. You can change this behavior by setting the trigger activation mode.
• Line Start:The camera initializes the acquisition of one image.
  If the Exposure Start trigger is enabled, the camera is now ready to receive Exposure Start trigger signals.
  If the Exposure Start trigger is not available or disabled, the camera automatically starts exposing the image. Note that in this case, exposure starts with a delay (see exposure start delay).

Exposure Triggers#

If available, you can use the Exposure Start, End, and Active triggers to control the exposure of a single image.

By default, these triggers are disabled, and the camera exposes images automatically.

If you enable these triggers, set the exposure mode to TriggerControlled, and the camera receives the corresponding signal via the trigger source configured, the following happens:

• Exposure Start: The camera starts exposing one image.
• Exposure End: The camera stops exposing one image.
• Exposure Active: When the trigger signal rises, the camera generates an Exposure Start trigger signal. When the trigger signal falls, the camera generates an Exposure End trigger signal. You can change this behavior by setting the trigger activation mode.

Trigger Sources#

You can set the trigger source using the TriggerSource parameter.

This defines how a trigger is triggered. For example, you can specify that a trigger is triggered by an electrical signal or by a timer signal.

Depending on your camera model, the following trigger sources are available:

Hardware Trigger Sources#

External Sources#

• Line1, Line2, Line3, Line4: The trigger selected can be triggered by applying an electrical signal to I/O line 1, 2, 3, or 4.
  If the I/O line is a GPIO line, the line must be configured for input.

• CXPTrigger0, CXPTrigger1: The trigger selected can be triggered by receiving a trigger signal from a CXP-12 frame grabber or a CXP-12 interface card.

  For information about configuring the CXP-12 frame grabber or the CXP-12 interface card, see the Basler Frame Grabber documentation and the Configuring a CXP-12 Interface Card topic. Triggering the camera via the frame grabber or interface card has the following advantages:

  • A short trigger delay.
    The trigger accuracy is less than 0.5 µs when using CXP-10 or CXP-12. It is less than 1 µs when using CXP-6, CXP-5, or CXP-3.
  • The generated I/O trigger packets are transmitted to the camera via the CoaXPress data cable. This may be useful for your cable setup.

  The CXPTrigger0 and CXPTrigger1 triggers correspond to the LinkTrigger0 and LinkTrigger1 trigger packet definitions in the CoaXPress Standard version 2.0.

Internal Sources#

• Action1: The trigger selected can be triggered using the Action Commands feature.
• Counter1Active, Counter2Active: The trigger selected can be triggered using the Counter feature. The trigger signal will be high (1) as long as the given counter is counting and low (0) as long as it is not counting.
• Counter1Start, Counter2Start: The trigger selected can be triggered using the Counter feature. A trigger signal is sent whenever the given counter starts counting.
• Counter1End, Counter2End: The trigger selected can be triggered using the Counter feature. A trigger signal is sent whenever the given counter stops counting.
• Timer1Active, Timer2Active: The trigger selected can be triggered using the Timer feature. The trigger signal will be high (1) as long as the given timer is running and low (0) as long as it is not running.
• Timer1End, Timer2End: The trigger selected can be triggered using the Timer feature. A trigger signal is sent whenever the given timer has elapsed.
• PeriodicSignal1: The trigger selected can be triggered using the Periodic Signal feature. A trigger signal is sent repeatedly. Its period is defined by the BslPeriodicSignalPeriod parameter.

Software Trigger Sources#

• Software: The trigger selected can be triggered by executing a TriggerSoftware command via the pylon API.
• SoftwareSignal1, SoftwareSignal2, SoftwareSignal3: The trigger selected can be triggered using the Software Signal Pulse feature.

Trigger Activation Modes#

You can set the activation mode using the TriggerActivation parameter.

This setting only applies to hardware triggering. It defines which signal transition activates the selected trigger. For example, you can specify that a trigger becomes active when the trigger signal falls.

Depending on your camera model, the following trigger activation modes are available:

• RisingEdge: The trigger becomes active when the trigger signal rises, i.e., when the signal status changes from low to high.
• FallingEdge: The trigger becomes active when the trigger signal falls, i.e., when the signal status changes from high to low.
• AnyEdge: The trigger becomes active when the trigger signal falls or rises.
• LevelHigh: The trigger is active as long as the trigger signal is high.
• LevelLow: The trigger is active as long as the trigger signal is low.

Trigger Delay#

You can add a delay between the receipt of a trigger signal and the moment the trigger becomes active.

To do so:

1. Set the TriggerSelector parameter to the desired trigger type.
2. Set the TriggerDelay parameter to the desired delay (in µs).

Specifics#

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