How to detect multiple holes in an image

[hd28]

Hello,

Could somebody give me some advice on detecting circular objects 

I have some difficulties to detect multiple holes in a circuit breaker using NI Vision Builder. After this, I want to set a coordinate system based on the location of those holes. 

In the attached pictures are the circuit breaker, those holes are marked in blue.

Thanks

[1100fps]

I'm going to suggest that it will be difficult to find the holes with any degree of accuracy without changing the illumination. The current lighting is casts shadows, that will throw off the tools that can identify circular objects.  A ring light, might work.

Even with improved lighting, the angular field of view is causing image distortion, which can also cause issues in finding accurate hole centers.  The cheap fix is to calibrate the image to remove geometric error, another approach is to use a lens with a longer focal length, but put it farther away from the part, and the Very Expensive solution is to use a telecentric lens..

If the holes are through the part, backlighting will offer exceptional contrast and allow finding the holes using blob tools.  Very simple and easy.  

I'm willing to discuss more if it will be useful.

Cheers

Robert