Vision doesn't detect all particles after increasing the illumination of an LCD

[Msengxxl]

Hi there,

we have a Imaging Source DFK31AF03 Camera in use with Vision 8.0 for detecting particles in an LCD-Display with Illumination.

That worked fine until development has increased the amplification of the illumination so that Vision now detects less particles (just 42 of 48).

I tried to adjust the camera by experimenting with shutterspeed, gain, brightness, gamma etc. but without effect.

Is there a possibility solve this problem?

[muks]

Adjust the lens. That should be your first thing since you say the change is just the illumination. Why are you adjusting the camera? Next will be to adjust the threshold settings.

[muks]

Did you consider the suggestion?

[Msengxxl]

Ok, thanks,

i will try it out, but the problem is: in the future i will have two different levels of illumination, the actual one that worked fined in the past and the one that is more illuminated.

So if i adjust the lens, i can only adjust it for one Type of LCD...

I need some kind of processing to equalize the now more illuminated sections, i guess

[Msengxxl]

By the way: where can i adjust the threshold settings?

[muks]

Again i will suggest you to adjust the lightings in such a way that you are not over exposing the bright illumination. Get a balance between the two. Do you have seperate routines for checking the illumination change or you have to do that in the same program?

[muks]

Do you have vision assistant installed? You can play with threshold values there

[BruceAmmons]

You can almost always cancel the effect of increased illumination by reducing the shutter/exposure time until the image matches the original illumination.  If you have two fixed illumination levels, you can use two fixed shutter speeds.

In the past, I have used algorithms to dynamically adjust the shutter speed to compensate for the lighting level.  If the image has more than 5% of the pixels at 255, I reduce the shutter by 10%.  If there are no pixels above 220 or so, I increase the shutter speed proportionally.  You would have to pick values that are appropriate for your application.

Using an auto threshold routine will also help, if you can find an auto method that works well for your application.

Bruce

[AnalogKid2DigitalMan]

Bruce's suggestion is a valid one. If you cannot adjust camera parameters, can you use a motorized mechanism with a neutral density filter to place in front of the lens to reduce image brightness for the higher illumination level?

-AK2DM

[muks]

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muks wrote:
Again i will suggest you to adjust the lightings in such a way that you are not over exposing the bright illumination. Get a balance between the two. Do you have seperate routines for checking the illumination change or you have to do that in the same program?

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I wanted to type lens there!!!!!!!!