Acquire Image (IEEE 1394) Controls

NI Vision Builder

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Acquire Images Tab

Acquire Image (IEEE 1394) Controls

The following controls are available on all tabs.

Control Name Description
Acquires and displays a single image from an IEEE 1394 camera. When you click this button, the step acquires and displays the next image provided by the camera. If you enabled the Triggered Acquisition control in the Trigger tab, the step waits for the next trigger signal to acquire and display an image.
Performs a continuous acquisition, or a triggered grab if Triggered Acquisition is enabled, and displays the image. When you click this button, the step starts the continuous acquisition and display of images. If you enabled the Triggered Acquisition control in the Trigger tab, the step waits for the next trigger signal to acquire and display a new image for each iteration. Click this button a second time to stop the continuous image acquisition.
Updates the Devices list on the Main tab.

Main Tab

The following controls are available on the Main tab.

Control Name Description
Step Name Name to give the step.
Devices Lists the image acquisition devices currently installed on the computer.
Video Mode Displays a list of available video modes for the IEEE 1394 camera currently selected in Devices.
Acquisition Mode Specifies whether the step returns the image currently being acquired or the last completely acquired image.
  • Wait for Next Image—Waits for the next available image before transferring an image.
  • Immediate—Immediately transfers the current image if it is newer than the image that was last acquired.
Tip  Set the Acquisition Mode control to Immediate when you want to acquire from multiple cameras triggered simultaneously. The first acquisition step acquiring from camera 1 synchronizes the inspection by waiting for the next trigger signal. In subsequent acquisition steps, set the Acquisition Mode control to Immediate so that the images acquired by other cameras on the same trigger as camera 1 are transferred immediately.

Features Tab

The following controls are available on the Features tab.

Control Name Description
Features Lists the features available on the camera you selected in the Devices table on the Main tab.
Mode Specifies how the selected feature is controlled and updated.
  • Manual (Relative)—Sets the selected feature to use values that do not map to real-world units.
  • Manual (Absolute)—Sets the selected feature to use values that map to real-world units.
  • Auto—Sets the value of the selected feature automatically.
  • One Push—Sets the value of the selected feature automatically the for the first acquired image then returns to manual control with the adjusted values.
  • Off—Disables the selected feature.
Value Specifies the value of the selected feature. You can specify the feature value manually, set the value of the feature to the result of a previous measurement, or set the feature to the value of a variable.

Trigger Tab

The following controls are available on the Trigger tab.

Control Name Description
Triggered Acquisition Enables the Trigger Mode control and its associated controls. When enabled, you can coordinate an image acquisition with events external to the computer, such as receiving a pulse from a detector that indicates the position of an item on an assembly line. The trigger signal must be connected to a trigger input of the camera.
Trigger Mode Specifies how the camera integrates with a trigger signal. The following options are available.
Note  Not all IEEE 1394 cameras support these modes. Check the camera documentation to determine which modes the camera supports.
  • Mode 0–Programmable Shutter—The camera starts integration from the external trigger input falling edge. Specify the integration time by defining the Shutter attribute in Measurement & Automation Explorer (MAX).
  • Mode 1–Pulse Width Control—The camera starts integration from the external trigger input falling edge. Integration time is equal to the low state of the external trigger.
  • Mode 2–Trigger Pulses Control—The camera starts integration from the first external trigger input falling edge. At the Nth external trigger input falling edge, integration is stopped. N is defined by the control parameter.
  • Mode 3–Internal Trigger—The camera issues a trigger internally. The cycle time is N times the cycle time of the fastest frame rate. N is defined with the control parameter. Specify the integration time by defining the Shutter attribute in MAX.
  • Mode 4–N Frames, Programmable Shutter—The camera starts frame integration when the external trigger input changes to an active value. Each frame is exposed for a duration specified by the shutter attribute. The number of frames is specified by the optional parameter, N, which must have a value of 1 or more.
  • Mode 5–N Frames, Pulse Width Control—The camera starts frame integration when the external trigger input changes to an active value. Each frame is exposed while the external trigger is active. The number of frames is specified by the optional parameter, N, which must have a value of 1 or more.
  • Mode 14—Vendor specific. Refer to your camera documentation for information about this trigger mode.
  • Mode 15—Vendor specific. Refer to your camera documentation for information about this trigger mode.
Trigger Timeout Specifies the amount of time, in milliseconds, to wait for the trigger signal before returning a timeout error.
Control Parameter In Trigger Mode 2–Trigger Pulse Control, this parameter N defines the integration time in the number of trigger input falling edges. In Trigger Mode 3, Internal Trigger, N defines the cycle time. The cycle time of the internal trigger acquisition is N times the cycle of the fastest frame rate.
Polarity Specifies if you reset the camera and start the acquisition of a new image on the rising or falling edge of the trigger signal.
Note  Not all IEEE 1394 cameras support the ability to set the trigger polarity. Check the camera documentation to determine which polarity options the camera supports.

Format 7 Features Tab

The following controls are available on the Format 7 Features tab.

Control Name Description
Region of Interest Specifies the acquisition Window. Use the following controls to define the acquisition window.
  • Left—X origin of the acquisition window. This value is rounded to a multiple of the camera unit width.
  • Top—Y origin of the acquisition window. This value is rounded to a multiple of the camera unit height.
  • Width—Height of the acquisition window. This value is rounded to a multiple of the camera unit height.
  • Height—Width of the acquisition window. This value is rounded to a multiple of the camera unit width.
Packet Size Specifies the size, in bytes, of each packet transmitted by the camera during an isochronous cycle. Decrease this value to allow multiple IEEE 1394 cameras to share bandwidth.
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