Oh my, FFT - fast fourier transforms! I haven't thought about those since grad school. Regards, Bob S.
On Wed, May 25, 2011 at 7:24 PM, Bruce Walker <[email protected]> wrote: > On 11-05-25 4:20 PM, Bruce Walker wrote: >> >> On 11-05-25 11:17 AM, David J Brooks wrote: >>> >>> A good friend of mine has a scan of an old family photo in pretty >>> rough shape and asked me last night if i could help fix it. I just got >>> the scan a few moments ago: >>> >>> http://www.caughtinmotion.com/picture0001.jpg >>> >>> and had a quick look. I'm not even sure i know how to go about >>> touching this up. I told he i would look and at least try. >>> >>> Any comments or help. >>> >>> She tried to send a large Tiff file but on dial up the 24mb photo >>> would not load so she just sent me a 2.5 MB jpg. >>> >>> Any help is appreciated. >>> >>> Dave >> >> As others have pointed out, your biggest challenges are (1) removing the >> paper texture, and (2) decreasing the softness. But it turns out that #1 >> isn't as bad as generally thought, and #2 can be addressed too. >> >> The solution to the first problem lies with the FFT, or Fast Fourier >> Transform. You convert your image into the frequency domain, look for >> symmetrical mid and high frequency components that shouldn't be there, mask >> them out and reconvert back to image space. >> >> You can uncross your eyes now. :) >> >> To prove that that works, here's your image after some processing I just >> tried ... >> http://dl.dropbox.com/u/2254722/picture0001-filtered2.jpg >> >> I used ImageMagick and "Fred's Scripts" (fftfilter, spectrum) to create >> the image spectrum and process the image, and Photoshop to create the >> filtering mask. >> >> You can deal with #2 by using Photoshop's Smart Sharpen filter set to do >> "local contrast enhancement" style sharpening. Basically you crank the >> Radius upwards to the range 16-32 and set the Amount down between 12% to >> 25%. I tried two passes with that and got reasonable results (not shown in >> the image above). >> >> Of course you also need to patch up the little places where the emulsion >> has flaked away, but the PS clone brushes can easily handle that. >> >> HTH. >> >> -bmw > > OK, I took the FFT processed result and did some spot-cloning, noise > reduction (Noiseware Pro), two passes of Smart Sharpening and finally levels > to improve black level and contrast/brightness ... > > http://dl.dropbox.com/u/2254722/picture0001-filtered2a.jpg > > Printed at a modest size on metallic paper, this would probably look pretty > good. > > -bmw > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
