Acquisition Phase
A MultiCam grabber is designed in such a way that it should operate during a non-interruptible amount of time in order to deposit an image into a destination surface of the host computer.
This non-interruptible amount of time is called the acquisition phase.
When an area-scan camera is operated in the VCAM or CTL mode, the acquisition phase is composed of a succession of "frame exposure" and "frame readout" sub-phases.
When a line-scan camera is operated in the PAGE mode, the acquisition phase is composed of a succession of "page delay" and "page scanning" sub-phases.
Considering the acquisition process in this manner provides a smart way to unify the description and the control in both situations.
In case of area-scan, the image data provided by the acquisition phase are called a frame. The number of lines constituting a frame is automatically inferred from the selected camera characteristics.
In case of line-scan, the image data provided by the acquisition phase are called a page. The number of lines constituting a page is chosen by the PageLength parameter.
The image data provided by an acquisition phase fits into the surface of the cluster defined in the host computer memory. There is a match between the size of the frame or page and the size of the destination surface.
Two events are introduced to account for the acquisition phase:
- SAP is a shortcut for the event marking the beginning of the acquisition phase (Start of Acquisition Phase)
- EAP is a shortcut for the event marking the end of the acquisition phase (End of Acquisition Phase)