[Work] about white balance

Yesterday afternoon, I was making mosaic from a set of images.
I had a big trouble with white balance.
I tried a lot of times. and was simply confident, since there are only to numbers to tune.

But I never reached the correct solution. All the results are either wierd or only a little bit near to my expectation.

I got more and more inpatient and nothing got better.
And finally I must leave my office.

On the way back to home, I got an idea: why not try the white balance on the big images, where we have the reference white paper.

Last night I tried the idea. I first found out the right magic numbers from the big images and then applied them to the cropped small images. But it didn't work at all. What's wrong with this scheme?

I thought there are something wrong with the cropping or the gamma correction.


This morning I corrected all these errors by working directly on the uncropped versions.
After making everything right, I cropped the result big images and got the smaller ones.



The lessons:
Keep the mind relaxed and open!
Find reference point for the white balance processing.