Re: Seeking Clarification of Procedure for Averaging Images


Thomas Hurd,MD
 

John, 

Thanks for showing that maneuver. I hadn’t tried it before, but it worked very well!

Obviously, the having fun with the the stack modes was just a little too much fun when I tried them. Maximum and minimum are good tricks to have. Imexpected a bit more from standard deviation.

Tom Hurd




On Jul 8, 2020, at 6:24 AM, John Gillespie <john@...> wrote:

You can make an average version by loading the images into a stack (File->Scripts->Load Files Into Stack). Select browse then click the images you want.
Once loaded (which may take a while if you choose a lot of images) select all the layers and then select Layers->Smart Objects->Convert To Smart Object (there is an option to do this on the file selection dialog but it doesn't always seem to work). Then select Layers->Smart Objects->Stack Mode->Mean.
You can also have fun with the other stack modes.

The alternative is to load all the images individually then adjust the opacity for each item, which needs to be done in proportion 1/N where N is the position from the bottom of the stack. So for 3 images it is 100% then 50% then 33%. With more than 5 images this is tedious and increasingly inaccurate as the percentage must be a whole number. So the first version is better if you are happy with a strictly equal contribution from each image. The second method is easier if you want to experiment with different weights.

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