detect defects in a pattern using a camera

[Yesh]

I have a pattern image with me, and I want to detect any defects in the pattern.

The pattern could be  concentric circles or a grid. I thought of using a imaq overlay

function and plotting it on the top of another image. Any ideas on this. RIght now I

am abl;e to threshold the image and see the defect. How should I approach this

problem.

[pallen]

If you can capture both a "good" image, you can use it to create a "Golden Template" and use it detect defects.

https://www.ni.com/docs/en-US/bundle/ni-vision-labview-api-ref/page/imaqvision/imaq_compare_golden_t...

It's a lot to read, but I really suggest having a look at the NI Vision Concepts Manual.  

If you're trying to recognize and categorize specific defects, then you'll have to "teach" those specific patterns.  Look into Pattern Matching for that.  

Good luck.