Using IMAQ Extract on a Calibrated Image

[Elodin]

Hello,

I'm a student new to Labview working on a project to get a web cam to identify and analyze the state of a checkers game board. My VI calibrates the image of the board to correct for distortion and to fit it to its real world coordinates. At this point I want to extract the game board from its surroundings to make the rest of my analysis easier. However, if I do this I end up voiding my calibration. Is there a way that I can make a new image based on my calibrated image so I can use the extract VI or do I need a new approach? 

Thanks for your time!

[Chris_1890]

It sounds like you're not passing the calibrated image to the extract VI correctly.  The extract VI requires a new memory allocation be made and then copies the source image to that location.  It then creates a new image at the new memory location with only the extracted portion of the original image.  If you don't handle your memory locations correctly, you may be overwriting your original image instead of extracting from it.  Make sure you are allocating a new memory location by calling a new IMAQ Create VI (and using a different string input) and feeding that into the Image Dst input of the IMAQ Extract VI.  This should ensure that you save the calibrated image before running the extraction.