Average Layers

[Timo Autiokari]

Averages all the Layers. The number of Layers must be a power of two (2, 4, 8, 16, 32, 64, 128, 256, etc ), otherwise the script issues an error dialog. All the Layers must have 'Normal' Layer-mode with 'Opacity' == 100%, these are NOT inspected by the script. Note that accurate Average result is possible only when the Document is in a linear RGB working-space. Do not have the Histogram palette open while running this script, it will slow down the script considerably.

http://www.aim-dtp.net/aim/photoshop/js ... layers.zip

A noise reduction example:


WBR,
Timo Autiokari

[xbytor]

Nice piece of work. There was a hardware device called "Snappy" several years back that did something similar. You would plug it in to a video source (like a tape machine, tv, or video camera) and (in one mode) it would generate an image that was similar to an average. I don't think it worked with as large of an image set as your script does. But it was an excellent tool tool for coaxing out additional detail from a set of still video frames.

---
I just did a bit of research. You can find out more info via google:
http://www.google.com/search?q=snappy+video
And it does look like you can still buy one of these via ebay, although the company that made the device shutdown in 2000.

-X

[Timo Autiokari]

Thanks X. At work I've actually used the Snappy in the past, maybe something like over 10 years ago, we had video cameras on optical microscopes. Now we use Canon MKII(n) cameras on those same scopes (metallurgical and stereo). Last week I did a test by averaging 16 MKII raw shots that were taken at ISO1600 and there was quite a lot of visible improvement (according to the theory the signal to noise ratio could improve up to sqr(N) times where N is the number of frames, provided that certain boundary conditions are fulfilled). We have the programmable Canon remote controller on this camera so taking the 16 shots, even with the mirror-up-first method, is very easy, just a press on the start button. But the whole process (from the start button on the remote to the final 16 shot average result) took as much as 15 minutes.

We btw have at the lab many imaging systems that employ frame averaging (among many other noise suppression techniques), e.g. a scanning electron microscope that does up to 8000 frames, an X-ray spay imaging system that has a video camera and does up to 256 frames and an EDS material analyzer ( it also collects images) and has no frame count limit.

I also took 16 X-ray images (that themselves were already 256 averages by that system). Averaging those 16 images did not give any visible benefit at all and only a very very small improvement by difference mode comparison.

WBR,
Timo Autiokari

[Timo Autiokari]

The video btw was an AVI from Fuji F30 digicam, taken under low light conditions. I used the excellent VirtualDub.exe v 1.7.2 freeware to extract the 640x480 pixel frames from the AVI, this 1.7.2 version will extract any number of frames automatically and does it very rapidly.

Timo Autiokari

[rishika]

How to use layout grids in DTP software or filters and effects in image manipulation sotware?