How to detect screws with IMAQ

[Rlima]

    Hi Amit

    I really apreciate your time for sugguestions.

    Correct me, if I'm wrong,   Do you mean to change the  "shutter speed" when you say to adjust auto exposure algorithm?

    I undestand the ilumination issue  I already was thinking that the current light is a problem.

    I'm having a hard time to accomplish this project...

    Best Regards.

    Reynaldo Lima V

[Rlima]

           Hi Amit..

           I just play with my camera setting in MAX,  I take this news pictures below,  I think this are a lot better  the screws

           are more defined,   any way I have to do more test prior to change all settings,  I have another problem, well it's not

           a problem, I will need to have different settings for the camera due to other inspection i do for the face plate that comes

           in several colors  (black, light gray, piano black) so one camera setting will not work.

           Take a look on the pictures.

           Best Regards 

[AmitShachaf]

Dear Reynaldo,

There are many ways to approach an imaging problem. One way is to write a sophisticate image processing that can tackle every image. The other way is to try to take the image in a way that will create significant features and that will make your problem a lot less difficult.

If you want to simplify your problem then you need create better illumination.

1. Some of your screws have too much light and some are too dark. You have too much light in the center. You need even illumination so all the screws get the same illumination.

2. Couple of your screws are over exposed. They are very reflective material so there image is saturated. You need to make sure they are not saturated.

3. You have now a front illumination. Try to make some peripheral illumination that will enhance the cross in the center of the screw. Try to find information on correct illumination on machine vision illumination website like: RVSI or Jenifer Dolan. Your illumination makes the problem very difficult.

Best - Amit,

[AmitShachaf]

Hi Reynaldo,

Try this link and look for Dark field illumination:

http://www.visys-inc.com/images/MV_Illumination_Guide_Oct_2002.pdf

Thanks - Amit,

[Rlima]

   Hi Amit..

        Thanks again for you sugguestions, I really apprecuiate your help,  I will review and evaluate this

        Best Regards.

[Sundar...]

Hello Rlima,

I would suggest you to effectively make use of polarizers to reduce out glare on the object of interest.

and preferably use diffused lighting , which will drastically reduce the effect of high illumination glare .

Even a custom lighting can be built very easily.

If you need any help on this do let me know.

Sundar. 

[Rlima]

          Hi  Sundar.

          I really apreciate your time for answering.

          I'm using diffuse white  light  300 led's from  2 Bit Inc..  model  Square Eye SW300,  see the link  http://www.2bitinc.com/html/Products/Lights/SquareEye/se300.html

          this works fine for all inspections but I'm having problems for detecting  the screws.   I'm thinking to design my own light.  I own a small bussines for software integration

          and electronic design.    I'm in contact with suppliers fro LED's to start doing some testing for light.   

          Just let me know what you think of the light  I'm using...

[AmitShachaf]

Hi Reynaldo,

You might want to try Dark Field illumination and not udiffused light. Most of the companies will give you a demo unit to try in USA.

Best - Amit,

[AnalogKid2DigitalMan]

Reynaldo:

This may be hard to implement, but you could fixture some lasers to point where the screws should be. Turn off other illumination and fire the lasers. If screw is present you will see the laser spot, no screw present would yield no reflected laser spot. Then use a threshold to determine if spot is present. If so, then the screw is also present.

Just a thought, again, not sure if it will work in your application or setup.

-AK2DM

[Rlima]

  Hi. AnalogKid.

  Thanks for your suggestion,

  I agree with you, it would be a good idea but i have an issues with this,  Cost for lasers sensor,  I have 4 radio sides with different

  screws quantities and severeal positions,  for one sigle modes and I have around 25 models in this equipment.   I'm looking  for a

  software solution.

  Thanks any way, its a very good idea... I really apreciate you support.