DAHENG-IMAGE MER-031-860U3C User Manual page 71

Mercury U3V Cameras User's Manual
camera is triggered, it begins to integrate and when the integration is over, the image data will be read out
immediately.
The MER-U3x series camera supports two exposure modes: overlap exposure and non-overlap exposure.
The user cannot assign the overlap exposure or non-overlap exposure directly, it depends on the frequency
of trigger signal and the exposure time. The two exposure mode are described as below:
 Non-overlap exposure
In non-overlap exposure mode, after the exposure and readout of the current frame are completed, the
next frame will expose and read out. As shown in the Figure2- 16, the N frame is read out, after a period
of time, the N+1 frame to be exposed.
The computational formula of non-overlap exposure frame period:
non-overlap exposure frame period > exposure time + readout time
Sensor Exposure
Sensor Readout
Time
Figure2- 16: The exposure sequence diagram in non-overlap exposure mode

Trigger acquisition mode in non-overlap exposure mode
If the trigger delay is greater than the sum of the exposure time and readout time, it will not occur
overlap exposure, as shown in Figure2- 17.
Sensor Exposure
Sensor Readout
Time
Figure2- 17: The trigger acquisition exposure sequence diagram in non-overlap exposure mode

Overlap exposure
In overlap exposure mode, the current frame image exposure process is overlap with the readout of
the previous frame. That is, when the previous frame is reading out, the next frame image has been
started exposure. As shown in the Figure2- 18, when the N frame image is reading out, the N+1 frame
image has been started exposure.
The computational formula of overlap exposure frame period:
overlap exposure frame period ≤ exposure time + readout time
Frame N
Frame N
Trigger
Frame N
Frame N
Non-overlap
Frame N+1
Blank
Frame N+1
Trigger
Frame N+1
Frame N+1
Non-overlap
Frame N+2
Blank
Trigger
Frame N+2
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