Mike, you need to review the slides from my AIC presentation
It was kind of like: 1) good flat calibration + 2) gradient removal + 3) linear adaptation.
I've built quite a lot of mosaics, not all of them have been successfully built with PI alone, but that's also due to the fact they're often rather massive mosaics 12, 24, 52 frames...
1 isn't very hard to achieve, at least getting close enough. 3 is done by the software. All you have left is 2.
Now, Juan says that IF your images are correctly calibrated and IF you've removed the gradients correctly, PI wil succeed. It will. What Juan doesn't tell you is that PERFECT gradient correction sometimes isn't easy. Sometimes it can be very hard. Sometimes, for the purpose of putting together a seamless mosaic while still inear, it's simply IMPOSSIBLE
That's why when building a mosaic I spend A LOT of time working on that (gradient correction). When most people are usually content with whatever their first DBE run gives them, I rarely use the first, second or third try, and keep modeling the background until I'm happy (I do not mean I run the DBE 3 or 4 times, but that I try, don't like it, go back and try it differently, and so on). On non-mosaics one doesn't need to be brutally accurate. When building mosaics, you have to. If you can't then you have to default to proceed with what you have and MANUALLY build your own background model afterward, something you cannot do with PI alone.
I'm familiar with Photoshop's Photomerge. I've used it a few times to put together already-processed images to build a larger mosaic, but for smaller mosaics you still haven't processed, I definitely suggest starting with the PI workflow. The DBE is a very powerful tool. See in what areas the seams are noticeable and model your background accordingly, by adjusting the parameters, replacing samples in different locations, etc. Always, ALWAYS look at your screen-stretched background model and see if it shapes according to the background and the areas where the seams are more noticeable. Rinse and repeat. Often, the time you spend on that won't be wasted (going the PS way and building your background model manually isn't any less time consuming), plus you'll become very good at using the DBE tool!
