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Beatsy

Joined: 05 Jul 2013 Posts: 1535 Location: Malvern, UK
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Posted: Wed Oct 24, 2018 6:45 am Post subject: Sharpening over-sampled images |
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For years I was of the opinion that pixel-level sharp was the only way to go. It didn't take long after joining this forum to be convinced otherwise! There is more detail (resolution) to be gleaned from over-sampled images at high mag (and N.A.). It's not *entirely* empty magnification.
However, the resultant fuzzy pictures continue to irk the "old me" a bit and I've tried many times to make them appear sharper. To date, nothing has worked to my satisfaction. Down-sampling does the trick, but restores sharpness and edge-contrast at the expense of (barely) resolved detail. Sharpening over-sampled imagery just causes halos and other artifacts that look nasty IMO. I tried adjusting radius and used many different sharpening protocols, and combos thereof, but never liked the outcome.
This issue mainly applies to microscope images of diatoms, taken using oil immersion to tease out close spaced punctae and other details at (and even beyond) the theoretical limits of resolution.
Am I missing a trick? Is it possible to improve edge-contrast and apparent sharpness of grossly or slightly over-sampled images without down-sampling them or introducing halos and false detail? Maybe there's a technique or two I haven't tried yet so any tips and tricks gratefully received. Thanks. |
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Lou Jost
Joined: 04 Sep 2015 Posts: 3840 Location: Ecuador
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Posted: Wed Oct 24, 2018 7:15 am Post subject: |
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I know you don't like Photoshop but the RAW filter sharpening algorithm does not usually introduce conspicuous haloes (unlike the old Unsharp Mask). _________________ Lou Jost
www.ecomingafoundation.wordpress.com
www.loujost.com |
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Pau Site Admin

Joined: 20 Jan 2010 Posts: 4859 Location: Valencia, Spain
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TheLostVertex
Joined: 22 Sep 2011 Posts: 298 Location: Florida
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