Machine Vision

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Which vision tools to use for attached defect

Could someone please recommend the best/fastest way to find the defects that are circled in the picture?  The VF grids circled are a little brighter than the other grids.



Visual Basic 6 with NI IMAQ 8.2.3 ActiveX toolset



AVT Guppy GF146 Firewire 1mp digital camera


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Do you have an image without the red circle around the defect?

Zach C.
Field Engineer
Greater Los Angeles

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Our quality department sent me the photo.   I'm trying to get an image without the red lines.  I will post when I get something.

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Here is the same picture without the redlines

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For this instance, you can detect the defect using a simple threshold function.  For vb6, I think this function is called imaqColorThreshold or similar.  With this RGB image, I used the threshold values of R = 0 - 215, G = 0 - 255, and B = 0 - 255.  Then inverted the new image using imaqInverse.  Then you can use the function imaqCountParticles to count the number of LEDs that are too bright. 


Now, the more important question is how repeatable this process is.  I'm making the assumption that you will want to use this same imaging process on a sort of assembly line to determine if there are defects in your LEDs.  This repeatability will depend on the environment that the image is being acquiring from, the camera settings, and the degree of the defect.  Let me know if you have additional questions.

Zach C.
Field Engineer
Greater Los Angeles

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