© 2016 Thorlabs Scientific Imaging
4 Programming (SDK)
101
4.2.3.2 Event / Message Handling
Triggering events for single frame capture
The following figure shows the time sequence when triggering the IS_SET_EVENT_EXTTRIG and
IS_SET_EVENT_FRAME events. The camera is prepared for triggered capture using the
is_SetExternalTrigger() command. An incoming trigger signal at the camera starts the exposure
and the subsequent image transfer. Upon completion of the data transfer, the
IS_SET_EVENT_EXTTRIG event signals that the camera is ready for the next capture. The
IS_SET_EVENT_FRAME event is set once pre-processing (e.g. color conversion) is complete and the
finished image is available in the user memory.
Note
The following illustrations show a schematic view of the image capture sequence. The sensor
exposure and readout times and the transmission times depend on the camera settings. The pre-
processing time depends on the API functions you are using (e.g. color conversion, edge
enhancement).
* Optional function. The start time and duration of the flash signal are defined by the "Flash delay"
and "Duration" parameters (see is_IO()).
Events in live mode (image sequence)
The following figure shows the time sequence when triggering the IS_SET_EVENT_FRAME and
IS_SET_EVENT_SEQ events. The camera is set to live mode using is_CaptureVideo() so that it
continuously captures frames. The IS_SET_EVENT_FRAME event is set once pre-processing (e.g. color
conversion) is complete and a finished image is available in the user memory. The
IS_SET_EVENT_SEQ event is set after one cycle of a storing sequence has been completed (see also
is_AddToSequence()).