User`s manual

AW00098504000 Image Acquisition Control
Basler ace Camera Link 121
7.9 Use Case Descriptions and Diagrams
The following pages contain a series of use case descriptions and diagrams. The descriptions and
diagrams are designed to illustrate how acquisition start triggering and frame start triggering work
in some common situations and with some common combinations of parameter settings.
These use cases do not represent every possible combination of the parameters associated with
acquisition start and frame start triggering. They are simply intended to aid you in developing an
initial understanding of how these two triggers interact.
In each use case diagram, the black box in the upper left corner indicates how the parameters are
set.
Use Case 1 - Acquisition and Frame Start Triggers Both Off (Free Run)
Use case one is illustrated on page 122.
In this use case, the Trigger Mode parameter for the acquisition start trigger and the Trigger Mode
parameter for the frame start trigger are both set to off. The camera will generate all required
acquisition start and frame start trigger signals internally. When the camera is set this way, it will
constantly acquire images without the need for any type of triggering by the user. This use case is
commonly referred to as "free run".
The rate at which the camera will acquire images will normally be determined by the camera’s
Acquisition Frame Rate Abs parameter when the camera is parameterized via Basler pylon or by
the Acquisition Frame Period Raw register when the camera is parameterized via direct register
access. If the Acquisition Frame Rate Abs parameter or the Acquisition Frame Period Raw register
(respectively) is disabled, the camera will acquire frames at the maximum allowed frame rate.
In the real world, cameras are used in free run for many applications. One example is for aerial
photography. A camera set for free run is used to capture a continuous series of images as an
aircraft overflies an area. The images can then be used for a variety of purposes including
vegetation coverage estimates, archaeological site identification, etc.
For more information about the Acquisition Frame Rate Abs parameter and the Acquisition Frame
Period Raw register, see Section 7.3.1.1 on page 78 and Section 7.3.1.3 on page 81.
The use case diagrams are representational. They are not drawn to scale and are
not designed to accurately describe precise camera timings.