image compare hurt by "noise" around edges within digitized image

[Jeff_H]

Using 1411 IMAQ card and an NTSC color camera. Retrieving only luminance information. Snapping the same image under the same conditions twice in a row, I get a difference in the images. This occurs around the dark and light edges within the images. How can I best deal with this? Thanks.

[JR_A.]

I don't know what is causing the "noise" but it could noise from the cable, noise in the camera or just the way the CCD is going to work. Ideally you would want to take care of the problem in hardware if that is where it is coming from. However, in your case it doesn't look that bad and using a software filter takes care of it pretty good. I used Vision Builder and applied a 'Median Filter' of the 3rd order and got the attached image. In LabVIEW you would use the "IMAQ NthOrder.vi" to perform this operation. Hope that helps.

Cheers,

JR A.
Application Engineer
National Instruments