How to use IMAQ Extract Contour VI to get the contour of a SEM cutting edge image?

[Ahryman]

Hi, I've been trying to use the IMAQ Extract Contour VI to get a contour of the cutting edge of a machining tool. After transform the SEM image into a binary one, it is sent to the IMAQ Extract Contour VI, but this last one fails to find the contour and send the message "Error -1074395732 occurred at IMAQ Extract Contour - 

Possible reason(s): IMAQ Vision: No curves were found in the image.". I guess the problem can be the parameters selected for the curve extration input. The Vi and the image are attached below. 

[Topper_Harley · Accepted solution]

Hi Ahryman,

thank you for using the National Instruments Forum.

IMAQ Extract Contour is not working with binary images but with U8 images. You can look that up in the detailed help page of the VI.

In your VI, simply delete the thresholding and that's it.

I attached the result image.

Regards, Topper Harley

[Ahryman]

Thanks for the help. Do you happen to known which algorithm is used by this VI to obtain the contour?

[Topper_Harley]

Please refer to the NI Vision Concepts Help document for an insight to the algorithm. You can access the Concepts Help via the Windows start menu under National Instruments » Vision » Documentation » NI Vision.