Photomerge algorithm

Hello,
I am new to this forum... I don't know how to create new topic...

Anyway, We have currently have a license for Adobe Photoshop CS2 and the main feature we are using there is the PHOTOMERGE Command.

We like to manually arrange the pictures during photomerge (as in CS2)... But in photoshop CS3, I can not find the way to Disable the "Attempt to align selceted layers based on content".

Does anyone know how to do this in Photoshop CS3?

Thanks.
From R.Vinoya

Thank you for your reply.

I am using CS3. The funny thing is that I tried Photomerge after processing images with "Auto Contrast" as well as about 95% overlap, and the images still could not merge. I will take a look at SIFT. Thanks!

Which version of Photoshop are you using? CS2 vs. CS3 is a huge difference.

Photomerge (CS3) works by identifying "features" in each of the images, and then matching up. The algorithm is called SIFT (Scale Invarient Feature Transform). For details, see:

http://en.wikipedia.org/wiki/Scale-invariant_feature_transform

It's hard to tell without seeing the images in question, but it could be the higher magnification images don't produce the kind of locally distinct features the algorithm needs to get traction on. Increasing the overlap and/or the contrast (e.g., via histogram equalization or similar techniques) may help.