Optical Removal, what am I missing?

[ToddSch1979]

Hello,

I have selected Optical Removal and adjusted the threshold, size, etc. I can see the changes updating when I select the overlay as “Marked,” but when I export, I don’t see any difference between the two files where “Optical Removal” is set to “On” versus “Off.”

What am I missing?

Thanks,
Todd

[ToddSch1979]

@seanharding do you use this at all? again, nothing seems to change on my scans, regardless of my settings.

[seanharding]

No, I don't use it. I believe @marcinz606 built it, but I have never really messed with it. I tend to do most of my dust spotting in Lightroom after I export from NegPy, mainly because I'm used to doing it there…

[thetalkingdrum]

I played with it a couple of times and I couldn’t get it to work all that well. I figured either I was doing it wrong, or it wasn’t working. There was some dust picked up, but not much.

But I have scanners with ice, so dust is in general not a problem for me. It was more out of curiosity.

I think I never tried exporting. If nothing is removed on export maybe open an issue on it.

[marcinz606]

it's simple luma thresholding that's pretty conservative with detection (as it's really easy to mistake specular highlights for dust), overall it works pretty well for small obvious dust spots but falls short for hair or long scratches.I might tweak it more going forward but obviously it never will be as good as IR-based detection.

[thetalkingdrum]

I think @ToddSch1979 maybe implied that what ever changes he saw in the preview was not carried on to the export?

[ToddSch1979]

This is correct. I am familiar with the difference between IR and software-based detection and definitely do not expect to see the same results. However, when I export the image, I do not notice any difference in the areas where "dust" was masked.

Example with the dust in NegPy

After export, the spec still appears.

[marcinz606]

Weird, can you upload that tif? Maybe something is being lost in some specific cases when scaling up the repair to full res. I tried on some of my old frames scanned with plustek without IR and the optical detection work is visible on export

[ToddSch1979]

Sure thing, here you go. I placed the Triplet, and the TIFF
https://SchweiNas.synology.me/SchweiDrive/d/s/19iAd0M30usGpVsu2ywaGKz0ZwvT8mLq/5TtksjUK-AW0qGFSLzYwCUBHMVrjTBfX--rygITzleA0

[marcinz606]

I tasked fresh Claude fable 5.1 with tuning optical removal algorithm on coolscan IR scans & IR removal as baseline and results are very promising :)

[marcinz606]

I merged it to main, improvements are really nice when it comes to detecion and repair

[thetalkingdrum]

Awesome! That will be great news for everyone doing camera scanning:)

[thetalkingdrum]

Did you look into Daniela Ivanova's research? https://daniela997.github.io/ Might be some interesting bits there too, and the code is open.

[ToddSch1979]

Hey there, I had a chance to test this out on a few frames and it does an impressive job getting rid of dust. But I did notice that it is very heavy handed, regardless of threshold or pixel size on high contrast areas. I submitted a "bug" report. Although not a true bug, it is still creating the inability to use this particular aspect of NegPy on the majority of images that I have tried it on.

#1079