Manipulating images at different spatial scales

Question

Is there software which will allow manipulating an image at different spatial scales? For example, change the contrast or brightness of features smaller than 50 px but larger than 10 px.

I have searched a bit about the topic, and I think one technique uses Gaussian or Laplacian pyramids (I didn't read in detail what they are). But right now I am not so much interested in the mathematical details of the technique, and I'd like to avoid understanding and implementing it myself. I'd like to know if there is software made for photo retouching that is reasonably fast and allows one to experiment in practice. "Unsharp mask" in Photoshop allows doing something similar, but it's limited in that it allows only one type of adjustment, and there's only one scale cutoff ("radius"). I'd like more control over selecting features with a given scale.

Answer 1

Although the scales are a little more firmly set in stone that you might like, the Topaz Labs Detail plugin (usable as a quasi-standalone with the free Fusion Express host; otherwise will work with any 8BF-compatible editor like Photoshop, Paint Shop Photo Pro, IrfanView, etc.) works at three levels of detail independently (or as close to independently as possible).

I use it both for capture sharpening/definition (where large-mass and medium detail definition are more important) and for output sharpening (microcontrast levels at and around the pixel level). There is a fully-functioning (no restrictions, no watermarks) 30-day free trial available for download, so you can test-drive it and see if it works for you.

It may not quite have the parametric control you were looking for, but I haven't found myself wishing there was an intermediate level between the ones provided (yet — one should always remember the yet). There is only one major downside to the software (and I'd suppose the same would be true for any software of this type), and that's that it can be very slow with very large images on a poorly-provisioned computer. For instance, a Nikon D800 image on a 1.8GHz Core 2 Duo processor with 2GB of RAM takes well over a minute to pre-process for the detail size divisions (I won't be processing D800 or medium format images on that laptop again), but with smaller images (more typical current DSLR sizes) or on a machine with more memory and processor speed, it's an acceptable performer.