ALLIED Vision Technologies Marlin F-201 - Manual (Page 113)

Controlling image capture
MARLIN Technical Manual V2.4.0
113
Controlling image capture
Shutter modes The cameras support the SHUTTER_MODES specified in IIDC V1.3. For all mod-
els this shutter is a global shutter; meaning that all pixels are exposed to
the light at the same moment and for the same time span.
Continuous mode In continuous modes the shutter is opened shortly before the vertical reset
happens, thus acting in a frame-synchronous way.
External trigger Combined with an external trigger, it becomes asynchronous in the sense
that it occurs whenever the external trigger occurs. Individual images are
recorded when an external trigger impulse is present. This ensures that even
fast moving objects can be grabbed with no image lag and with minimal
image blur.
Camera I/O The external trigger is fed as a TTL signal through Pin 4 of the camera I/O
connector.
CMOS sensors For CMOS sensors, a global shutter is not common. Normally a rolling curtain
shutter is used to shorten the exposure or integration time. The curtain's
width defines the integration time and the curtain sweeps with the frame
readout time over the image. Although this is appropriate for still images,
image distortion will be created with moving objects, because the upper
image part is scanned earlier than the lower image part. For this reason the
MARLIN F-131 features a non pipelined global shutter only. A side effect of
this type of global shutter is that the integration or shutter time is added to
the readout time, thus affecting the frame rates to be achieved.
Trigger modi
Marlin cameras support IIDC conforming Trigger_Mode_0 and
Trigger_Mode_1 and special Trigger_Mode_15 (bulk trigger).
Trigger Mode also known as Description
Trigger_Mode_0 Edge mode Sets the shutter time according to the value set in
the shutter (or extended shutter) register
Trigger_Mode_1 Level mode Sets the shutter time according to the active low
time of the pulse applied (or active high time in
the case of an inverting input)
Trigger_Mode_15 Programmable mode Is a bulk trigger, combining one external trigger
event with continuous or one-shot or multi-shot
internal trigger
Table 37: Trigger modi