Bit wise Image Compare

[mfitzsimons]

What would be the fastest way to see if an image has changed?  I am buffering reference images (IMAQ Read Image & Vision Info) and need to know when the reference image changes.  The routine doesn't need to "match" the image but only needs to be able to detect change.  Looking for a solution that would execute fast.  I could do a color image to array and match the arrays but feel this is even slower than just doing a pattern match.  Any suggestions are welcome.

Matt

[mwenger]

Could you save the the original file to a Temp location and then compare the file size on a byte level?  Seems that would run pretty fast, but I guess that is all relative.  But if the change is small enough the "byte" level comparison may not be enough either. 

What are you looking for speed levels? 

or would this be a live image analysis? 

[TiTou]

Calculate the diff image and do a histogram on that diff image.

What's your image type?

[TiTou]

That's what I have in mind :

It is pretty fast. Hope it helps.

[CAS_MattF]

I will have to check it out but that is the type of unique solution I am looking for.  Just thinking there have to be a better way than doing a pattern match to determine is the image has changed.  I can't use any size related because the sized will be always the same for multiple reference images.  I am using direct digital capture.

[nisargsolanki]

Hi,

Could you please provide a labview file for this image. I am not able to find Labview example of 'compare image' ... 

Thanks 🙂