Detect Dirt on a Camera Image with Vision Assistant

[Cardinal1664]

Hello

I want to test the cleanliness  of a camerachip.

I tried to make a dirt detector for a camera image with Vision Assistant 2011 SP1.

I modified the Cell Analysis from the Solution Wizard.

My Vision Script isn't able to detect all dirt piratical on the Camera Image.

Maybe you have any tips to optimize my scrip other a other solution.

[Stephan_D]

Hallo Cardinal1664,

i have tested your Vision Assistant script with both of your images. For me, the result looks good. It would be helpful, if you can describe, what you want to improve.

[Cardinal1664]

Thanks for your answer.

On the Image dirty_Cam4.png you can see not so a dark point. My script can not detect that point.

I have marked that point on dirty_Cam4_marked.png.

The "dirty_Cam4_Vision_Result.jpg " is the result from my Vision Script.

My Script can't detect that point! I want to Improve my script that i can detect dirt with a weak contrast.

[Stephan_D]

Hallo Cardinal1664,

thanks for your additional information. The point in the black circle is realy hard to see and i think it would be almost impossible to detect this object on the picture. I would try to impove the contrast of the image bevor i try to optimize the script. Maybee you can use a blue, red or green light to iluminate your picture. It would also be an option to make the ilumination more homogenous. In the provided picture is the light on the top right side ind the brightness decrease over the rest of the image.

[Cardinal1664]

Thanks for your answer.

I know that in the image the top right side ind the brightness decrease over the rest of the image. But thats about the camera and I'm not able to improve that.

An other Ilumination is not possible!

Thanks for your help

[Christian Mergl · Accepted solution]

You could use "IMAQ Equalize" (could be found in the Lookup Table Function of the Vision Assistant) right after you open the image to spread the histogramm over the whole bit depth.

Christian

[Cardinal1664]

Thanks Christian

I tried it with the Lookup Table function.

I played a litle bit around with it and I choose the Lookup Table squere:

Square—Reduces contrast in dark regions. Similar to Exponential but with a more gradual effect.

And I'm very happy with the result!

Take a look at the scrip.

Thank's Stepahn and Christian