Reduce Noise using 32-bit Photoshop Image Stack Averaging

[AT2336]

what is this

[jeffhrose]

I see what you are getting at, perhaps if you had used a very grainy picture to start with it would have been more obvious:)

[jeffhrose]

But who would want a picture like that? How is that noise reduction when the original had no noise to reduce and the finished picture was worse than a noisy picture???

[digitalArtform]

@jeffhrose There is no 'original picture.' All you have is extremely grainy surveillance camera footage, no single frame of which makes any sense at all. That's where you are starting.

[digitalArtform]

@jeffhrose I'll give you a concrete example. In the movie ID4 the Empire State Building footage (just before it exploded) was extremely grainy. That's all I had. A grainy shot. I replaced each frame with a running average of the previous 20 frames and the shot became so low in grain that it looked great in the movie. Once it explodes it's grainy again (no averaging was possible due to things being in motion) but who could notice since debris was flying everywhere, anyway.

[EpicsodeOne]

Thia video is HAUNTING ME WITH ITS WTFness!

[digitalArtform]

@EpicsodeOne See what you can do to make it go viral.

[digitalArtform]

@EpicsodeOne See the new video response for a better explanation

[EpicsodeOne]

Guys guys guys, you don't know what this video is about, this video is a! Because the, and can't the it. When you are don't you can exactly. See? I alomost shunned this tutorial with WTFness!

WHAT THE HELL DUDE? CAN YOU PLEASE EXPLAIN TO US, not what this video is all about but WHY DID YOU POST IT??????

[jeffhrose]

So, you made a mess of the picture then showed us the original and then what???

[digitalArtform]

@jeffhrose The comments on this crack me up.

[digitalArtform]

@jeffhrose See the new video response for a better explanation

[Iloveyougagaloo]

Is this a how to fuck up a picture tutorial?

[digitalArtform]

@Iloveyougagaloo It is. Yes. You probably don't need anyone to teach you how to fuck up a picture, though. Am I right?

[digitalArtform]

@Iloveyougagaloo See the new video response for a better explanation

[wxb200]

Maybe it's the weather, but I had no idea what you were aiming to teach with this video...

[digitalArtform]

@wxb200 Just screwing around. Read a thread from February 19, 2010 called 'Stacking Images in Photoshop CS4 to reduce noise' on the web site dpreview. Same basic idea, only I wanted to try big chunky noise instead of small grain. Also I'm using 32 bits instead of other usual methods.

[digitalArtform]

@beregueda LOL what do you gotta train to catch?

[debstar2005]

whats the point of this ?

[digitalArtform]

@debstar2005 What if you are in an art museum that allows photography, but not tripods or flash? You could shoot a bunch of grainy high ISO photos, stack them, average them, and end up with a nice one. What if you have a bunch of crappy frames of surveillance video of a parked car and you can't make out the license plate but you need it... same deal.

[debstar2005]

@digitalArtform Ohhh i c now - thanks for clearing that up for me. Thanks Alot

[jgda9rs]

have you tried a test print on any of these photos say, like a 11x14 size?

[digitalArtform]

No, but I didn't invent this process, either. Astronomers use it. The one time I did use it in a big way was on some grainy footage of the Empire State Building explosion in ID4, a film on which I supervised the computer animation.

[jgda9rs]

hmm, might have to try it sometime. thanks for the upload btw. i was just wondering how or what

applications it works best for. but i guess this is

better than noise reduction in ps.

[digitalArtform]

@jgda9rs As you rightly point out, it has limited use. You have to have a bunch of images that are identical in every way except grain.

[jgda9rs]

why not just use some decent f stop settings and expose properly to reduce noise ? i really dont get this at all. no pun intended.

[digitalArtform]

What if you need to read the license plate on some noisy surveillance camera footage? What if you are in a museum that allows photography but no flash or tripod?

[crtl9697]

hello, is there a part 2 to this video ?

[digitalArtform]

No, but if you visit the box on the right, click 'more info' and visit the link at the bottom of the text you'll see some material about removing noise using a stack of identical but grainy high ISO images.

[digitalArtform]

A commenter whose comment I accidentally deleted writes: i don't get it. just where is the comparing of the differences in the noise. looks like you got to the end showing an arty look and THEN WHAT? you didn't show us anything that reduces the noise.

[digitalArtform]

The 'arty look' is what happens when you combine 8 extremely noisy (spotty) photos. If you combined 800, you'd get a pretty noise-free original back. To see a more to-the-point example using real high ISO grainy noise in a more realistic example, check the link in the comment bar on the right (under 'more info')

[digitalArtform]

Stack the images in layers. Use the LINEAR DODGE (ADD) blend mode to sum all the layers. You will blow out the image way past white. No worries. Kick into 32-bit mode and dim the sum back into a usable range. For a true average, dim it by a factor of (1 / N layers)