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Posted on 09/06/11 5:50:41 PM |
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chris berry
Overhead Overlord Posts: 724 Reply  |
Load files into stack
Just used "Load files into stack" - in this case it took 100 shots of the Chicago Bean sculpture which had a lot of tourists in front of it. Using Smart Object and meridian rendering... it removed every single tourist. Can any one explain how? Would love to know how this works. Chris |
Posted on 10/06/11 7:56:34 PM |
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Sophie
Political Parodist Posts: 595 Reply  |
Re: Load files into stack
Just seen a video about this. I think it is 'median' rather than meridian which might mislead others reading this post and the image stacks facility is only available in extended versions of CS3, 4 and 5. Image stacks I understand are a collection of system analysis tools. If you are talking about the same process, you have to import each shot as a separate layer in one canvas. Next, the layers are auto-aligned so that photoshop matches up the pixels in each layer and aligns them. Next, the layers are converted to one smart object and the Stack Mode accessed via the edit menu. From the Stack Mode tools, Median is the one that can get rid of people standing around in front of something! It looks at the aligned pixels (light, dark, colours) in each stacked image. It gets rid of all the pixels that don't match in the other images and keeps only the pixels that do match. I think that is about the gist of it. |
Posted on 13/06/11 07:45:47 AM |
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Steve Caplin
Administrator Posts: 6994 Reply  |
Re: Load files into stack
Exactly! |
Posted on 13/06/11 11:00:55 AM |
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Daniel
Poser Professor Posts: 192 Reply  |
Load files into stack
Chris, “Median” filters have many applications and there are many flavors of them. PS runs one flavor of this filter to get rid of unwanted items in a stack of images (as Sophie describes very well). What is interesting with Median filters is that they can also get rid of the noise (which is unwanted as well) but might be present in one image only. Almost all of the commercially available noise reduction SW (for example from Topaz) is based on a flavor of this filter. The involved mathematics can be quite complicated, but in short what median filter does is to look at each pixel and its nearby neighbors to decide whether or not it is representative of its surroundings. And then based on an algorithm it replaces that pixel with another one (a mean value in the simplest case) if the pixel was found not to be representative of its surroundings! I hope this helps. 
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