automatic recognition in photoshop

pfaffenbichler · Post by **pfaffenbichler** » Fri Feb 05, 2010 2:43 pm

Recently someone in the Photoshop MacIntosh Forum was asking about re-sizing archeological images according to a ruler in the image semi-manually (and Paul Riggott helped the original poster out).
But that reminded me of a thread about automatic reccognition of a ruler and scaling according to that – which I cannot find, though.

Paul mentioned that xbytor and Michael L Hale may have posted here regarding recognition in Photoshop, but I have not found the pertinent thread yet.

Anyway: I suspect it should be possible to have Photoshop recognize forms (on the basis of a sample image of said object, probably provided no significant perspectival shortening happened and the lighting is fairly even), because that seems to be part of what Photomerge does to align images based on content.
Now I’m aware that this conclusion may be faulty, but does anyone of You have an idea how something like this could be implemented with a Script?

xbytor · Post by **xbytor** » Fri Feb 05, 2010 6:31 pm

Assuming that the ruler was a standard size, the simplest thing to do would be to have the user mark the long edge of the ruler with the pen tool. A script could then use the path to align the image and do whatever resizing/re-rezing is needed. If you want the script to automatically locate the ruler, too, the problem becomes much more difficult (obviously) and may not be practical in JS.

Mike Hale · Post by **Mike Hale** » Sat Feb 06, 2010 1:34 am

I think that with an Extended version of Photoshop and a ruler that has an unique color it would be easy enough to come up with a way to to fully automate to any scale. You might be able to come up with something without the Extended version.

But if the ruler is not parallel along the length or hard to find with a script - all bets are off.

I have looked at the Photomerge code several times. I'm not sure it would help but if it can it would not be easy.

pfaffenbichler · Post by **pfaffenbichler** » Sat Feb 06, 2010 1:58 pm

Thanks for getting back to me.

xbytor, the solution Paul offered the poster was just such a semi-automated one with paths.

Michael, the Photomerge-code is in many ways out of my league … and I cant seem to find a lot of documentation on some of the stuff therein.

Do You know how the banknote-recognition-feature (I’m not sure if it’s still part of Photoshop, but it was some time ago) operated?

Mike Hale · Post by **Mike Hale** » Sat Feb 06, 2010 3:59 pm

pfaffenbichler wrote:Do You know how the banknote-recognition-feature (I’m not sure if it’s still part of Photoshop, but it was some time ago) operated?

No, I think that was dropped in CS3 and I think that it must have been native to Photoshop or a plugin written in some flavor of C.

With Photomerge, and I could have this wrong, it looks for features common in two or more images and adjusts them to match. I'm not sure that it would know something is a valid feature with a single image.

But maybe if you have a reference image with the ruler at a known scale Photomerge could align the images enough that a script could then set the scale to the other images.

larsen67 · Post by **larsen67** » Sat Feb 06, 2010 5:02 pm

http://en.wikipedia.org/wiki/EURion_constellation

pfaffenbichler · Post by **pfaffenbichler** » Mon Feb 08, 2010 8:32 am

Thanks.

Mike, I did try having Photoshop auto align a mocked-up ruler that was transformed and placed in a larger image with the untransformed one, but Photoshop declined to to insufficient overlap.
Seems it’s not the right route.