Basler acA2000-165, Руководство пользователя

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AW00123402000 Image Acquisition Control
Basler ace USB 3.0 151
Use Case 3 - Frame Burst Start Trigger On - Frame Start Trigger Off
Use case three is illustrated on page 152 .
In this use case, the Acquisition Mode parameter is set to continuous. The Trigger Mode parameter
for the frame burst start trigger is set to on and the Trigger Mode parameter for the frame start trigger
is set to off.
Because the frame burst start trigger mode is set to on, the user must apply a frame burst start
trigger signal to the camera. In this case, we have set the frame burst start trigger signal source to
input line Line 1 and the activation to rising edge, so an externally generated electrical signal
applied to Line 1 will serve as the frame burst start trigger signal. The Acquisition Burst Frame
Count parameter has been set to 3.
When a rising edge of the electrical signal is applied to Line 1, the camera will exit the "waiting for
frame burst start trigger" acquisition status and enter a "waiting for frame start trigger" acquisition
status. Once the camera has acquired 3 frames, it will re-enter the "waiting for frame burst start
trigger" acquisition status. Before any more frames can be acquired, a new rising edge must be
applied to input line 1 to make the camera exit the "waiting for frame burst start trigger" acquisition
status.
Because the frame start trigger is set to off, the user does not need to apply frame start trigger
signals to the camera. The camera will generate all required frame start trigger signals internally.
The rate at which the frame start trigger signals will be generated is normally determined by the
camera’s Acquisition Frame Rate parameter. If the Acquisition Frame Rate parameter is disabled,
the camera will acquire frames at the maximum allowed frame rate.
This type of camera setup is used frequently in intelligent traffic systems. With these systems, a
typical goal is to acquire several images of a car as it passes through a toll booth. A sensing device
is usually placed at the start of the toll booth area. When a car enters the area, the sensing device
applies an electrical signal to input line 1 on the camera. When the electrical signal is received on
input line 1, it serves as a frame burst start trigger signal and the camera exits from the "waiting for
frame burst start trigger" acquisition status and enters a "waiting for frame trigger" acquisition
status. In our example, the next 3 frame start trigger signals internally generated by the camera
would result in frame acquisitions. At that point, the number of frames acquired would be equal to
the setting for the Acquisition Burst Frame Count parameter. The camera would return to the
"waiting for frame burst start trigger" acquisition status and would no longer react to frame start
trigger signals. It would remain in this condition until the next car enters the booth area and activates
the sensing device.
This sort of setup is very useful for traffic system applications because multiple frames can be
acquired with only a single frame burst start trigger signal and because frames will not be acquired
when there are no cars passing through the booth (this avoids the need to store images of an empty
toll booth area.)
For more information about the Acquisition Frame Rate parameter, see Section 6.3.1.1 on page 91 .