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AW00123404000 Image Acquisition Control
Basler ace USB 3.0 145
6.7.2 Overlapping Image Acquisitions for acA1920-25,
acA2500-14, acA3800-14, acA4600-10
When using a camera with a rolling shutter, there are two common ways for the camera to operate:
with “non-overlapped” acquisition and with “overlapped” acquisition.
In the non-overlapped mode of operation, each time a frame is acquired the camera completes the
entire acquisition process for a frame, consisting of exposure plus sensor readout, before
acquisition of the next frame is started. The acquisition of a new frame does not overlap any part of
the acquisition process for the previous frame. This situation is illustrated in
Figure 65 with the
camera using an external frame start trigger.
In the overlapped mode of operation, the acquisition for a new frame begins while the camera is still
completing the acquisition process for the previous frame. This situation is illustrated in Figure 66.

Overlapped frame acquisition cannot be performed when the camera is set
for global reset release rolling shutter mode. Overlapped frame acquisition
can only be performed when the camera is in the electronic rolling shutter
mode.

acA3800-14 and acA4600-10 cameras allow overlapped frame acquisition
only when they are triggered internally ("free run"), i.e. when Trigger Mode is
set to Off for the Frame Burst Start trigger and for the Frame Start Trigger.
Frame Acquisition N Frame Acquisition N+1 Frame Acquisition N+2
= Line Exposure
= Line Readout
Time
ExFSTrig
Signal
Fig. 65: Non-overlapped Acquisition