Colorspace independent channel equalization analysis discussion

[El Goblina]

I posted a little analysis I've used to highlight not-very-apparent details in an image. There was some interest in my technique, so rather than muddling up an already massive thread, I figured it'd be better to discuss the intricacies of the technique here.

At its core, this is a one-liner with ImageMagick.

convert photo.jpeg -colorspace RGB -separate -equalize -combine output.png

Instead of RGB, you can use any colorspace ImageMagick supports. On Debian, the list is: CIELab CMY CMYK Gray HCL HCLp HSB HSI HSL HSV HWB Lab LCH LCHab LCHuv LinearGray LMS Log Luv OHTA Rec601Luma Rec601YCbCr Rec709Luma Rec709YCbCr RGB scRGB sRGB Transparent XYZ xyY YCbCr YDbDr YCC YIQ YPbPr YUV

If you post some photoshops here, I'll apply the approach and show you how it makes the edits more obvious.

I'm skeptical of this claim about that old image of Vic being Photoshopped. I'm just not seeing it.

There's a strategy I use for visual art where I take an image and then equalize each channel in varying colorspaces to generate neat false-color versions of a photo. One of the strengths of this strategy is that it occasionally makes inconsistencies very plain. This analysis is not showing anything atypical in the image. I don't find the error-level analyses very persuasive here.

I've attached a few different colorspaces to show the kind of details this equalization technique pulls out of the image. Left to right, these colorspaces are xyY, HSI, RGB, YUV.
View attachment 794985View attachment 794992View attachment 794993View attachment 794994

 

[Immortal Technique]

I posted a little analysis I've used to highlight not-very-apparent details in an image. There was some interest in my technique, so rather than muddling up an already massive thread, I figured it'd be better to discuss the intricacies of the technique here.

At its core, this is a one-liner with ImageMagick.

convert photo.jpeg -colorspace RGB -separate -equalize -combine output.png

Instead of RGB, you can use any colorspace ImageMagick supports. On Debian, the list is: CIELab CMY CMYK Gray HCL HCLp HSB HSI HSL HSV HWB Lab LCH LCHab LCHuv LinearGray LMS Log Luv OHTA Rec601Luma Rec601YCbCr Rec709Luma Rec709YCbCr RGB scRGB sRGB Transparent XYZ xyY YCbCr YDbDr YCC YIQ YPbPr YUV

If you post some photoshops here, I'll apply the approach and show you how it makes the edits more obvious.

Our KF friend, Ren

 

[El Goblina]

Our KF friend, Ren
View attachment 795091

This is not the greatest choice of image because there is a lot of JPEG noise that obscures edits, but the blur strokes on the forehead pop out quite a bit. Colorspaces: HSL, xyY

 

[Immortal Technique]

This is not the greatest choice of image because there is a lot of JPEG noise that obscures edits, but the blur strokes on the forehead pop out quite a bit. Colorspaces: HSL, xyY

View attachment 795106View attachment 795109

Interesting. Now, for the obvious blur strokes.....are we talking the pink/deep purple spots or the business above the right eye-brow (the viewers right side)?

 

[El Goblina]

Basically, everywhere from the top of her eyes to half-way up her forehead is almost entirely artificial. The quality of her saved post-Photoshop JPEG was higher than the quality of the original image. This is why it looks all blurry. Any real shaping that we can see has been made with tools, not from the source image. If you compare how "smooth" this section is compared to say her cheeks (this is clearer in the HSL/left image), it's apparent that there's work being done here.

The strokes are mostly running along the left-right axis, but angled along the directions she wants her eye sockets to contour along.

 

[El Goblina]

Interesting. Now, for the obvious blur strokes.....are we talking the pink/deep purple spots or the business above the right eye-brow (the viewers right side)?

For comparison, I also did an export from an image forensics tool, which highlights the smoothness, but doesn't really make the strokes as visually apparent as my images.

https://29a.ch/photo-forensics/#pca

 

[Rei is shit]

please

 

[Exigent Circumcisions]

This is the good kind of autism.

 

[Big Nasty]

What the fuck

 

[Gouki]

Does this only show smoothing or some other stuff like edited IG model asses etc. ?

 

[Kirito]

Can you tell me if this is photoshopped?

 

[El Goblina]

please
View attachment 795167

HSL colorspace. There isn't anything very obvious here. It looks like something was removed off the concrete on the side of the rail furthest from the whale. I'm not entirely persuaded that this analysis is correct, but if I had to point at anything suspicious, it would be that.

Does this only show smoothing or some other stuff like edited IG model asses etc. ?

Like I've said before, there's nothing particularly magical about this approach (other than using a program called ImageMagick); all it really does is transforms the colors in the image so that some variations within the image are emphasized. Occasionally this makes "subtle" work really obvious.

All this is, really, is a way to occasionally transform things that someone with a good eye sees into something that someone with a weaker eye might see.

Can you tell me if this is photoshopped?

CIELab colorspace. Based on the noise patterns, I'd say that the spoon is shooped in. Looking at the original image, there's no shadow under the spoon or anything, so that seems to be pretty obvious.

You all understand autism around here and like playing with it. This is fun.

 

[gobbogobb]

Pick any recent Zoe Quinn full body or face only pic.

 

[feral cat #6385]

After monstrous and the whale here is a pallet cleanser. R cats real or was one added?

 

[XYZpdq]

View attachment 796285

After monstrous and the whale here is a pallet cleanser. R cats real or was one added?

this could finally prove the Secret Italian Supercat

 

[Recoil]

This is absolutely fascinating. I love learning about shit like this. Thank you, @farmcat