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Thread: Masking based on edge detection?

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    Masking based on edge detection?

    Does anyone know of any masking software that uses edge detection to make a mask?

    I'm trying to fix an image that has colour-blotch noise over intricate details. The blotches happen to be a similar colour to some of the detail, so colour-based masking doesn't work as well as I'd hoped. Luminance-based is also iffy as the blotches darken some areas down to the level of detail in other areas.

    I could do it by hand, but it'd probably be quicker to do the four or five hour round trip to retake the shot!

    I saw Colormancer's Smooth Area Detection plugin, which is the closest I've found to what I (think I) need, but that highlights the edges with a thick line (marking either side of the boundary), so doesn't quite do what I want.

    Any ideas?

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    Re: Masking based on edge detection?

    tried capture one? There's a topaz masking program too

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    Re: Masking based on edge detection?

    Capture One must be about the only one I haven't tried yet...!

    But unless I'm missing something, none of the new 'clever' masks (a la Topaz, where you mark the inside & outside and let it do its thing) are appropriate for this task. There isn't an inner part and outer part, it's just one big pattern.

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    Re: Masking based on edge detection?

    How about Select>Color Range, combined with the Color Replacement Tool, in Photoshop?

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    Re: Masking based on edge detection?

    Quote Originally Posted by NoBob View Post
    How about Select>Color Range, combined with the Color Replacement Tool, in Photoshop?
    No, because the noise and the detail are the same colour in places...

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    Re: Masking based on edge detection?

    Here's a portion of the problem...



    You can see that some of the coloured parts have been changed, and the plain background colour in the pattern also varies. Because the noise fades in and out it would be an ideal candidate for edge detection techniques.

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    Re: Masking based on edge detection?

    If that isn't a 100% crop, can you do one or two of a particularly troublesome area and post it here?

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    Re: Masking based on edge detection?

    Unfortunately this is at 100%, which makes any necessary work particularly fiddly!

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    Re: Masking based on edge detection?

    What happens when you run it through Topaz Denoise?

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    Re: Masking based on edge detection?

    I tried a few croma denoise options in various programs, they all help remove the noise - especially when you run the image through more than once - but alas they all strip the real colours from the image also.

    I have lots of programs on trial at the moment (for various issues ), and your suggestion gave me an idea to look at greyscale options. In the Zoner package I found a filter called 'Dynamic Thresholding' which produces a b&w effect very close to what I could use for a mask. I might have to alter the variables slightly for different parts of the detail, but it's the closest I've got so far.

    Thanks for your input, and for giving me the spark of an idea!

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    Re: Masking based on edge detection?

    I was also going to suggest duplicating the layer a couple of times, converting each layer into a Smart Object, and selecting different areas on each layer using Select>Color Range (but using the Highlights, Mid-tones or Shadows from the drop down menu) and use the selection to create a mask for each layer. Apply a denoise plugin to each layer and adjust the opacity of each layer.

    Maybe adjust the contrast with a Curves Layer to help make the details stand out from the background when making the selection.

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