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.

Hinweis

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).

Fig. 153: Events in hardware trigger mode

* 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()).

Fig. 154:
Events in live mode

* Optional function. The start time and duration of the flash signal are defined by the "Flash delay" and "Duration" parameters (see is_IO()).

Function List

is_DisableEvent()	Disables a single event object.
is_EnableEvent()	Enables a single event object.
is_EnableMessage()	Turns the Windows messages on/off.
is_ExitEvent()	Closes the event handler (Windows only)
is_InitEvent()	Initializes the event handler (Windows only)
is_EnableAutoExit()	Automatically releases the camera resources when the camera is disconnected from the PC.
is_WaitEvent()	Waits for uEye events (Linux only)

Flowchart: Enable events

Icon_Cursorhand2

Fig. 155: Flowchart - Enabling event handling (Windows)

Flowchart: Enabling Messages

Icon_Cursorhand2

Fig. 156: Flowchart - Enabling message handling

Suggestion for improvement? Send us your short Feedback on this chapter. Thank you very much!

For technical questions please contact you local distributor or use the support form on our website.

Home > C: Programming > How to proceed > Capturing images >	History back Previous chapter Next chapter Print
Event/message handling