Overview of a Simplified Acquisition Model
Simplified model for an acquisition chain
The grabber can be a part of the frame grabber in case of boards supporting multiple cameras simultaneously. Boards with simpler architecture embed a single grabber.
As represented in the picture, a grabber can be sourced by a set of cameras, among which only one is active at a time. The source selector is a programmable device that establishes the connection to one of the incoming cameras. This is typical of the switched acquisition situation.
Some grabbers can only be connected to a single camera, whereas there may be other grabbers in the board connected to other cameras. This is typical of the concurrent acquisition situation.
The image data extracted out of the active camera is processed by a set of grabber-specific devices. Refer to the frame grabber documentation for details.
Generally speaking, the rationale for the acquisition path is to leave in some part of the host computer memory a digital representation of the image produced by the camera. The format of the stored image is directly usable by the application software.
The MultiCam system provides a specific object to represent a memory buffer able to receive an image. This object is called the surface, which is an instance of the Surface class, and owns a set of defining parameters.
A high degree of flexibility is provided for implementing multiple-buffer image destination structures. To achieve this, the surfaces are grouped into a cluster of surfaces.
A channel is the temporary association of a grabber connected to a camera delivering data to a destination cluster. Each channel should be linked to a cluster. The channel is able to transport an image from the camera towards one of the surfaces constituting its cluster. In the above picture, the surface receiving the image is noted as "Filling surface".