overbright image

[Little Bird]

Hi,

we have a grab image and image processing LV application, when the camera
is triggered, then the application make a grabbing.

Some grabbed images are over bright, like the camera gain changed, but next time ,
the gain sounds return to normal, the camera is SONY industrial camera, 1024
by 768, in LV we have tried to initilized the camera setting at the
begining and also tried init camera before each triggering.

We don't know if it's a camera qulity, statbility problem, or it's common
in all indutrial camera, we have 10 cameras there. The problem happens randomly to all cameras.


thanks for any input.


Anne

[MikeeB]

Hi
I would check two things
1) What frequency are the lights on the system. If they are 50/60Hz and your shutter speed is fast (<30ms) you will capture the cycling of the lights.
2) The cameras can be set up to have the shutter timing equal to the time of the trigger pulse. This again will affect the light levels per acquisition.

Mike

[Little Bird]

Hi Mike,

We are using LED. So no lighting cycling.

The shutter speed is 2 ms and the trigger signal is 1ms.

Thanks a lot for your reponse.


Anne

[TommyBoy]

Hi guys!

do you use firewire cameras?
We have nearly the same phenomena.

When I start up my app, the images are too bright.
Restarting the app or starting MAX solves the problem.
Looks like I need to load the MAX configuration file twice.

I use 4 firewire cameras, software triggered, with fixed gain and shutter.

LV 7.1
IMAQ vision 7
IEEE 1394 toolkit 1.5.2
WinXP pro

[Little Bird]

Hi,

We are using fireware cameras.

Do you also set up camera parameters in software?

In our case, the application is for real time system. We are not able to know when the over bright image happens and then restart the app or use MAX.

What we do is using MAX to pick up right camera setting parameters to make sure good quality image. Then with the RT application we set the cameras setting in program with the parameters we get from MAX,but sometime we got bad images, overbright images.

Thanks.

Anne

[nipun]

Hello Anne,

You can use IMAQ Histogram to find out the mean intensity of your image. Then use that to ignore any image that has an average intensity over a cutoff level. I hope this helps you out.

Regards,
Nipun M
Applications Engineer
National Instruments

[Little Bird]

Well, we can do that. But it doesn't help because we will still miss that trigger.

Thanks for your suggestion.

Anne

[Jaime Rodriguez]

DId you guys fix this problem because I am having the same issue of randomly overbright images on image acquisition of moving parts?

[Torba]

Hello Jaime,

Do you have the same setup as Anne's?  Have you checked the items that Mike Bailey suggested?

Mike T

National Instruments

[Jaime Rodriguez]

Yes. I did check but I do not have those problems.

I have LEDs

and my shutter is at 1/1000 sec, and frame rate 30 fps