Match altered image to its original

[Brian.Raila]

(11-01-2021, 11:07 AM)Ofnuts Wrote: This is very odd. There are 32 regularly spaced (step=8) peaks in the output histogram (that are the same on all channels). IS the image quantized in the process? If so, forget it, no way you are going to get a proper image after compensation. That would be a bit like transforming a cow so that it eventually comes out alive from the meat grinder.

Odd, indeed.  I couldn't agree more.

You'll see in a moment that I've gone to some lengths to get this mystery to the next level, hopefully toward conclusion; spent the last few hours to gather a meaningful collection.

I'm delighted that you're hanging in here, Ofnuts.  Your assistance dates directly back to 2-20-21, in aiding my grokking of Color Mapping.  You provide – first, accuracy; then clarity; then simplification – in that order, which is how it should be.  So check this out:

I have not given a full account of the known associations with this ghosting.  I knew where lay the cause, but not the why.  For a considerable time, I dodged it; found workarounds; but always said, "Some day I'm gonna hafta' get this damn thing figured out.  So here goes.  I think this'll offer some insights as to possible quantization, even-ness of steps, and so on.

The culprit is Flash Player -associated imagery in PDFs.  So, you have all your regular arsenal of Adobe Acrobat.  I'll have to followup with you on some of my fairly robust productions.  But here's what I've long known – Any placement of Buttons, atop Flash content, brings about this ghosting, affecting the 'internal' Button imagery.  A few points:

1. It occurs only in the regions where Button overlaps Flash.
   
2. It is not evident; everything looks dandy in Buttonville, until the Flash content is 'activated' [which can occur from user interaction, or JavaScript engagement], which immediately initiates the ghost process.
   
3. Following activation [in these instances the Flash material consists of video segments], the effect remains, even when the video stops.
   
4. The effect is constant, 'even', and unvarying [thank God for that, anyway]
   
5. When the content is 'disabled', the overlying button stuff returns to where it was [though, in practice, disabling never really has any reason to occur, so let's just call it 'perpetual' {until document close/reopen, of course; things always open in intended fashion}].
   
6. It appears to matter not, the characteristics of the underlying Flash – that is to say, it appears to be in no way dependent on luminosity, contrast, color values, etc. of that video.
   
7. Especially remarkably - it matters not a bit whether video is dynamic, or static – moving or still.  So it's not like there's a relation to processing load.
   
8. In all my specimens sent this way, video is at a standstill.
   
9. Intermediate Buttons, sandwiched atop the video, and beneath the uppermost Button/icon layer, appear to have no effect; i.e. it doesn't help to sandwich in a black button.
   
10. Everywhere else in Acrobatville, a layer is a layer is layer.  Not here.  Flash imparts a spooky magnetic, remote, field over them buttons.
    

Cool, huh?

– – –

Quite a set of specimens have I sent up to the folder, "Flasher the Friendly Ghost".  It's likely more than you need to see, but I believe illustrates the phenomenon accurately.  The file names, especially if gobbled alphabetically, are essentially self-explanatory.

As for what to do about it, I'm not certain that it's beyond hope.  Even a close approximation would be beneficial.  I don't anticipate the need to 'splice'/merge/combine original with ghosted images, as a split-down-the-middle singularity [though that liberty would be grand to have in store].  More typical is that somewhere on the page, or an earlier page, or an upcoming page, there may be conceptual comparison.  I don't wish to impart cognitive discomfort.  To that end, though, sometimes close is good enough.

Ultimately, I can't get around there being a 'flick-of-the-switch' change, at the moment of content activation.  A processed, prepared-for-ghosting image, sitting in place atop Flash, is gonna change at that moment.  I have to live with that.  But I can mitigate, by causing activation when the user is not looking.  The objective is that the activated/prepared-for-ghosting image will then at least closely resemble its unprepared/not-sitting-atop-Flash counterpart, which may reside nearby.

– – –

What do call a cow with no legs?


A: Ground beef.

---

(11-01-2021, 11:51 AM)rich2005 Wrote: Using the tiff files, I got quite a good color match using the elsamuko plugin. I did crop the 'letter boxing' top and bottom though.
The correction curve looks like this:



A comparison clip attached.  The tiffs are different from the other pngs. The ghosted tiff is less sharp and does not have those 'edge artifacts'  as in the png's.  I wonder what in your processing adds those. Sharpening maybe ?

Cool, Rich.  Thanks.  I'ma check it out.

I will obtain the plugin.

Letterbox, schmetterbox.  Of course.  They have no place here.  That's an artifact of accurately generating the sample specimens, uniform in the region of interest.

Now, tiff, png.  My eventual use demands png, to gain transparency in Adobe Acrobat.  So that's the ultimate production format.  But I do all the Gimp processing from tiffs, when possible.  Unless there's a reason I oughtn't in this instance.  And also I assumed tiffs the way to go in swapping specimens.

You probably gathered that my original original is a jpeg [1500 x 1004].  It's up in the Upload Repository.  Tiff made directly from that.

– – –

Alright – I just looked.  Neat.  They're gonna love you in Amsterdam.

Here's the big-picture question.  As to "what in your processing adds those", That's the whole quandary.  It is not my processing.  It's Adobe's.

Check my latest post here.  I'm really looking beyond an individual instance, and trying to engineer a generalized fix, if there turns out to be a predictable offset/remedy.