comparing 2 images using pattern matching

[a_p_c]

HI,

i'm doing a project that have to be able to compare 2 images. i have to divide the image into smaller boxes to make sure that i can identify where the errors are. first i tried to use "pattern matching" and "colour pattern matching" but i always experienced an error about contrast.

could u please suggest any example or any source of information for me??

(i have already looked at the example "Pattern Matching Example.llb Pattern Matching Example.llb " but the problem is that i don't have to search for a pattern, all i have to do is just to compare them)

thanks

[Aaron B.]

Hello,

If you simply want to compare how similar one image is to another you can use the "IMAQ Absolute Difference" function. Here is a quick example that compares one image to another and determines if they are significantly different using this functionality and a few other Vision functions. It was written in LabVIEW 7.1. I'm not sure what version of IMAQ it was written in, but it was last modified in May of 2005, so it can't be a very recent one. If you need to, upgrade your driver for free at:

"http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BBB002C0D10?opendocument&node=132070_US"

Regards,

Aaron B.
National Instruments

[a_p_c]

Thank you very much Aaron,

but I can't open that VI. I don't know if it is because I'm still using LabVIEW7.0Express???

Could you please post it in version 7.0?

Thanks you again.

[Aaron B.]

Hello,

I've taken a screenshot of the Block Diagram and highlighted the important 3 VIs that you will want to use. The rest is not necessarily relevant to your application. Take care!

Regards,

Aaron B.
National Instruments