
7.2.2 Strobe
In many applications, objects in the field of view can be moving too rapidly to be properly imaged
under normal conditions. A combination of the high-speed shutter and a strobe may be used to
stop motion. It is often desired to synchronize the strobe action with the camera exposure. For this
purpose, a STROBE output pulse is generated within the camera. The STROBE output pulse
allows an external strobe light to be turned on during the exposure period. Since the duration of the
exposure is a user-programmable setting, the start-time (relative to the vertical timing of the
camera) and the duration of the STROBE output pulse also vary, depending upon the shutter
setting.
The strobe output pulse is generated to coincide with the exposure period. It is asserted (rising
edge) after the last "charge dump" pulse in each frame. It goes low at the next CCD readout pulse
(see above diagram). The strobe light can be activated at any time during the HIGH duration of the
strobe output pulse.
7.2.3 Reset & Shutter
In some applications, it is necessary to synchronize the camera to an external event. In order to
allow flexibility, two camera RESET inputs are provided. These inputs are called VRST_INT
(TTL-pin39 of the DB44 connector) and INPUT1(differential LVDS-pins [34,35] of the DB-44
connector). The default level for both these signals is logic "HIGH". Within the camera, these two
signals are logically AND-ed together and the resulting RESET signal is used to reset the counters
within the camera-timing chip. If either the TTL (VRST_INT signal) or the differential LVDS
(INPUT1) is unused it floats HIGH due to internal pull-ups. The other signal may be pulled
"LOW" to cause a reset to the camera.
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