Best noise filter for large format scans?

[edwinn]

Got a hold of a large trove of B&W school photos from decades ago, digitally scanned in large format. Trouble is the texture of original printing (like tiny ink dots and paper surface texture combined) cannot easily be sharpened without the whole photo starting to `buzz´ with white speckles. Tried using the stock `High Pass Sharpen´ with a larger aperture which seemed to make them a little sharper and better.

Any suggestions on sharpening techniques? How about a reasonably priced commercial plugin for PSP X4?

Thx

[Jean-Luc]

Could you post an example?
A crop of the original scan would be appreciated.

[edwinn]

These samples are a cropped, full scale view of a scanned yearbook photo.

The first image at top is baseline, next with Smart Photo Fix, and last Unsharp Mask – which is buzzing white.

Looks like there's an `interference pattern´ made worse by sharpening.

May be able to find a better example.


-Ed

[Jean-Luc]

The repetitive pattern (grid) may be partially removed with the Fast Fourier Transform plugin (see another discussion below).

What I did:

Opened PSP 32 bit.
Increased the image to true color (8bit channel).
Applied the FFT plugin:

Removed the "spikes" and some other areas with non-uniform noise. 'Remove' means painting with the average magenta color of the image.
Preserved the central cross.
The resulting image is here:

Applied iFFT:

See this discussion with another example:
https://forum.corel.com/viewtopic.php?f=56&t=68482

[edwinn]

That looks very useful! What's the significance of viewing FFT results with the magenta channel? The Brit in the how-to video used the green channel to `paint out´ the pole pairs (above and below x-axis). Plus he used black circles to null the poles. Does black or magenta equal a null (zero)?

Found a webpage on it: https://www.3d4x.ch/Swift%27s-Reality/F ... okov/16,35



-Ed

[Jean-Luc]

What's the significance of viewing FFT results with the magenta channel?

I observed that when I painted with white, the iFFT result doesn't produce any image. I tested to paint the center of the central cross with black and the iFFT resulting image was very dark. If I transform the 'magenta' image in black and white (greyscale), the iFFT doesn't produce an image. My deduction is that this plugin produces a magenta image and needs to be corrected with magenta too. In my usual work, I use magenta because it is the result of different testing and produces the best result.

[edwinn]

What's the significance of viewing FFT results with the magenta channel?

I observed that when I painted with white, the iFFT result doesn't produce any image. I tested to paint the center of the central cross with black and the iFFT resulting image was very dark. If I transform the 'magenta' image in black and white (greyscale), the iFFT doesn't produce an image. My deduction is that this plugin produces a magenta image and needs to be corrected with magenta too. In my usual work, I use magenta because it is the result of different testing and produces the best result.

The filter is working VERY WELL for me with scanned yearbook photos. In one FFT filter video, the user selected and viewed Magenta channel, and in another they viewed Green channel and painted dark gray brush on the poles (white spots). I'm not finding a way to view these channels with PSP 14. Also I found an FFT brush specific to the FFT filter (it was a dark charcoal color) but was unable to `add in´ that tool so it would appear in PSP 14.

So I'd like to use the BEST channel and the best brush to filter `interference patterns´ when scanning process printed images.

[Jean-Luc]

In one FFT filter video, the user selected and viewed Magenta channel, and in another they viewed Green channel

They use perhaps another plugin.
The plugin I use doesn't need to select MAGENTA or green channel.
As shown in my examples, I paint with magenta on the FFT result image and apply the iFFT after painting. That's all.

GMic has a Fourier Transform plugin. It seems to work with Gimp but I cannot make it work in PSP (64 bit):
https://www.youtube.com/watch?v=3137dDa6P4s

[MarkyW]

I just did a quick adjustment in Topaz Denoise AI. You can probably get a little better if you play around with the settings more. And maybe Sharpen AI might help, too, depending.

Tug_trim_sample 2.png (237.97 KiB) Viewed 1931 times

[edwinn]

Getting GREAT results here with FFT interference pattern filter. Attached are displays from the transform image: post FFT, and pole mask with pure magenta brush (255, 0, 255).

I'd like to learn more about separating the channels like in this video: https://www.youtube.com/watch?v=Du6ENFLAoF4&t=130s

Which is the best procedure? Thx


-Ed

[edwinn]

I just did a quick adjustment in Topaz Denoise AI. You can probably get a little better if you play around with the settings more. And maybe Sharpen AI might help, too, depending.

Anyone have a LINK describing Topaz filters in PSP on this forum? I remember reading about them here years ago. Just unpack Topaz Denoise into `plugins´ folder? There doesn't seem to be a way to contact Topaz Support, or a browser script is blocked for `Contact Us´ link.

[Kathy_9]

The Topaz forum is here -> https://community.topazlabs.com/ and Topaz Labs support is here -> https://support.topazlabs.com/

[edwinn]

This from the Topaz Community board;

"There are no Topaz 8bf files in My PSP Files/Plugins folder. When I want to add a Topaz product as a plugin I go to Preferences/click the Plugin option/ click on Add and then go to Program Files/Topaz Labs and click on the folder for the new product. PSP doesn’t automatically copy anything to My PSP Files/Plugins. The ones in there were downloaded to the Downloads folder and moved there manually. There won’t be any Topaz 8bf files in there unless I put them there myself."

So now I'm wondering if Topaz `installs´ the plug-in files in a Topaz folder? and I simply go to PSP Plugin Option, then find and ADD that folder.


-Ed

[LeviFiction]

Yes just add the folder where the .8bf files are located on your harddrive to the Plugins Folder locations and it'll load up the plugins that it finds there. No need to move the files.

[Kathy_9]

So now I'm wondering if Topaz `installs´ the plug-in files in a Topaz folder? and I simply go to PSP Plugin Option, then find and ADD that folder.


-Ed

Yes, the legacy plug-ins are found in both C:\Program Files\Topaz Labs and C:\Program Files (x86)\Topaz Labs.

The newer AI plug-ins are found in C:\Program Files\Topaz Labs LLC.