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Photo Retouching "Improving" photos, post-production, correction, etc.

Automatic Skin Smoothing.

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  #151  
Old 11-06-2010, 07:43 PM
ShadowLight ShadowLight is offline
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Re: Automatic Skin Smoothing.

... I still don't quite get why you insist on c-50... wouldn't you want more precision in the mid-tones smoothing?
(after all you are smoothing the skin here)
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  #152  
Old 11-06-2010, 07:46 PM
bakerser bakerser is offline
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Re: Automatic Skin Smoothing.

Quote:
Originally Posted by ShadowLight View Post
... I still don't quite get why you insist on c-50... wouldn't you want more precision in the mid-tones smoothing?
(after all you are smoothing the skin here)
I'd love to have full precision, but at the end of the day 1/32,768 error is fine by me. Maybe that makes me a copout in your book, but I'll get by.
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  #153  
Old 11-06-2010, 08:07 PM
ShadowLight ShadowLight is offline
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Re: Automatic Skin Smoothing.

"errors" can be defined in different ways, but generally it's unpredictable variation of the expected result.

In this case you just have predictable different distribution of precision.

For me having more precise mid-tones is more beneficial, but that doesn't mean that there is an "error" just because it doesn't match another algorithm's result.

since you probably never used variation in the contrast (above -50) to setup the IHP, try playing with it in SkinSmooth and see what the effects are.

Last edited by ShadowLight; 11-06-2010 at 08:20 PM.
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  #154  
Old 11-06-2010, 08:37 PM
bakerser bakerser is offline
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Re: Automatic Skin Smoothing.

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Originally Posted by ShadowLight View Post
"errors" can be defined in different ways, but generally it's unpredictable variation of the expected result.
I've been using the context which you put to it in the first place; the context which drew me into the conversation - that the algorithm you're using has an origin in frequency separation (or at least its colloquially-defined gaussian basis, but let's not get into that!). As such, I've based the definition of "error" as I've reported it around that. If at any point you wish to change that context and consequently the definition so as to have lesser error, so be it. I've been saying that, if you're happy, you're happy.
Quote:
Originally Posted by ShadowLight View Post
In this case you just have predictable different distribution of precision.

For me having more precise mid-tones is more beneficial, but that doesn't mean that there is an "error" just because it doesn't match another algorithm's result.
If that 1/32,768th per channel of one pixel matters to you, I'm glad for you. That's dedication, and I admire it.
Quote:
Originally Posted by ShadowLight View Post
since you probably never used variation in the contrast (above -50) to setup the IHP, try playing with it in SkinSmooth and see what the effects are.
I've used your application, and for the reasons which I've explained ad nauseum in this thread and others find it - aside from the notion of the interface and workflow - entirely ill-matched to the quality of work I try to do. It's that notion which has kept me going.

On a general note, though, this will be my last reply to you. I've conferred with several folks both on and off this site (all of whom have been following our discourse here) and come to the conclusion that I've [more than] reasonably made my case and explained the image science involved in what is and is not happening here. While I will happily continue to answer any questions which other members wish to ask (either publicly or privately), it seems that I will never be able to get through to you. I apologize for that, as I had allowed myself to hope that I could. My arrogance has failed us both. I honestly wish you and your family the best with your move and getting settled into wherever it is your trip will be taking you.
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  #155  
Old 11-06-2010, 08:52 PM
ShadowLight ShadowLight is offline
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Re: Automatic Skin Smoothing.

so be it
don't forget to test your final results in your studies.
(and don't neglect the conditions for errors to occur)

take care
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  #156  
Old 11-06-2010, 09:20 PM
Visna Visna is offline
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Re: Automatic Skin Smoothing.

Wow! So good debate about HP technics... By the way I found 6 ways to achieve that for now... Maybe a couple more to find too...

All of of my tests look like pretty the same, but when you look closely some come with less artefacts.

One of good way to test your technics it's to compare from the original picture like I did.

1- OP = Orignal Picture / HP = High Pass / LP = Low Pass
2- Add HP* layer with Linear Light mode at 50% opacity with gaussian blur picture at the same radius
3- Compare picture with layer Difference blending mode into a Group
4- Add level to clip the value at the top ( you won't see anything, if you not clip the value )

HP* ( could be an other way to achieve HP )


OP-OP = 0 ( perfect match and no artefacts)


(HP + LP) = OP-OP = 0... True? Not really... Seemless but not a real perfect match for all of my test. The quality depend what kind of the technic to achieve the HP. Nor the offset apply technic are better...



Both of your technics are not perfect and have some more to do... Need More precision and flexibility... I made many tests on very frackel face and no one come with satisfies results ( Portraiture, Beauty Box and so on )...

By the way PS must use flotting point some day and better algorythm for all filters...

I made something interresting for skin smoothing but it's take a lot of ressource... But it's end up with very good result...

Anyway both will find the answer...

Thank you!
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  #157  
Old 11-06-2010, 09:28 PM
bakerser bakerser is offline
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Re: Automatic Skin Smoothing.

Quote:
Originally Posted by Visna View Post
(HP + LP) = OP-OP = 0... True? Not really... Seemless but not a real perfect match for all of my test. The quality depend what kind of the technic to achieve the HP. Nor the offset apply technic are better...
If you're looking for a lossless separation, see it described here. Otherwise, it's not possible to accomplish with just two layers and the tools we have available.

Completely agree that a fully-FP PS would be a great upgrade, but I don't think we'll see that before it's GPGPU aware and at that it's a topic for another thread. But a great idea just the same .
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  #158  
Old 11-07-2010, 01:49 AM
Flashtones Flashtones is offline
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Re: Automatic Skin Smoothing.

Quote:
Originally Posted by bakerser View Post
I hope you'll try using a Custom filter as described in this thread yourself to see what the actual results are. They're quite as I've described them (as perfect as a single layer implementation can be), but if you run into trouble please let me know and I'll help you work through it.

Sean, sorry, I'm not clear on the bandpass SO workflow with the custom filter. (And you were changing the offset depending on luminance?) However, I trust you on it's accuracy, so unless it has advantage over C-50 feel free to spare yourself the trouble to spell it out on my account..

I'm also not clear on the difficulties ShadowLight was having implementing it. Is it difficult to code?
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  #159  
Old 11-07-2010, 05:14 AM
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Der_W Der_W is offline
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Re: Automatic Skin Smoothing.

I guess Sean just changed the offset to show that it really doesn't matter because of the high pass that is invoked later (as long as the offset doesn't clip any values. That's why you would go with 64 when recording actions as this will never clip values).

P2P described the process of scripting the custom filter here: http://www.modelmayhem.com/po.php?th...5#post14094943
But ShadowLight uses flash from what I've heard so I have no idea how different this would work.
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  #160  
Old 11-07-2010, 05:43 AM
bakerser bakerser is offline
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Re: Automatic Skin Smoothing.

Quote:
Originally Posted by Flashtones View Post
Sean, sorry, I'm not clear on the bandpass SO workflow with the custom filter. (And you were changing the offset depending on luminance?) However, I trust you on it's accuracy, so unless it has advantage over C-50 feel free to spare yourself the trouble to spell it out on my account..

I'm also not clear on the difficulties ShadowLight was having implementing it. Is it difficult to code?
Jonas is correct about my rationale - I used different #s simply to illustrate that mean value is irrelevant when calculating the HF. It would be different if we were teasing out the low frequency (which does depend upon the mean), but for the HF the starting mean doesn't matter. Any value between 0 and 127 was going to work just fine.

It has no inherent advantage over Contrast-50 unless you find that it works better in your workflow for some reason.

SL's difficulty with it was in simply getting the filter order wrong - he was halving contrast after the fact vs. before it. If he was having additional difficulty, I missed it.

As to the coding, the lines which Jonas linked to are exactly what could be added into the current SkinSmooth codebase in order to get it running. The Flash panel is controlled by / interoperates with Javascript code, so it's all the same behind the scenes. I have no idea whether P2P's knowledge of the script system far exceeds that of the average coder (it wouldn't surprise me), or if this is something which should have been obvious. I sure didn't know it.
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