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Showing results for tags 'attribute'.
Hello! I am running a system with GigE camera with NI framegrabber in continuous acquisition mode - in which I change some attributes every now and then. So far I have been using following scheme to assert I am getting correct image after attribute change: change attribute read "Last buffer number" property -> n run IMAQdx get image.vi set to "buffer' and parameter n+2 (+2 being due to the fact that i assumed attribute change arrives to camere during running exposure that will be unaffected by attribute change - hence i needed to discard "next" buffer) Unfortunately I still every now and then acquired image that obviously was aquired with previous attributes (e.g. I've dramatically increased.decreased exposure rate, while acquired image was very similar to previously acquired one). Guessing that it may have something to do with buffers I have increased "magic number" from +2 to +3. It indeed helped, but after longer usage I have discovered, that it only reduced the frequency of the error. Hence I needed to design more "bulletproof" solution that will satisfy my timing requirements (stoping and starting acquisition is out of question as it takes more than 100ms what is unacceptable for me) I would like to: change attribute acquire information from camera that will allow me to fetch image acquired with changed attribute For such purpose I have discovered IMAQdx events - especially "Attribute updated" and "frameDone". Unfortunately, I could not find any detailed documentation about those functions. Therefore I would like to ask you for help to determine when 'Attribute updated" is triggered. Is it when: driver receives the command and pushes it to camera? (pretty useless for me as I cannot relate it to any particular exposure) camera confirms getting it (then assuming it arrives during an ongoing exposure, I'll discard "next' image and expect second next to be correct camera confirms applying it (then I assume that next image should be obtained with correct settings) camera confirms it managed to acquire a frame with new parameter (pretty unlikely scenario - but the i'd expect correct image to reside in "last" buffer) Could you help me determine which case is true? Also should I be concerned about the fact that there may be a frame "in transition" between camera and IMAQdx driver which will desynchronize my efforts here?