Auto identify different pixels from 2 layers in order to "auto-select". Possible?

[Gustavo Del Vechio]

Hi

I just made these 2 images in order to try to explain the concept.

It's a simple simulation for test purposes, ok? Not a real situation yet.

Look at these 2 images:

First (just background):

Second (background with "objects" and it's shadows):

These 2 images/illustrations has exactely the same background...no light difference, no resolution difference, no color difference. The unique (at least visual) difference between these 2 images is the little shoes and it's simulated shadows.

In a reduced thinking... or thinking in a pixel grid (raster), the second images has some different pixels more or less in the center of the canvas. But the rest of the image is identical.

In this condition, I was wondering if there's any Photoshop feature that could automatically identify these "different" pixels, then select them or maybe "isolate" them?

I first tried putting each image in a Photoshop layer, then using blend modes to see any result, but no one gave exactelly the result. Also tried to make a smart layer/object from the 2 normal layers, then using stack modes, but no one also achieved too much.

Again, it's just a test...I know there are various Photoshop cutting and removing pixel's tools, including Adobe Sensei's power...

But I was wondering this technique: if having such feature, maybe in a studio, with a controlled light, temperature and professional camera settings, I could first take a photo from the background, after take a new photo with any inserted object (like a shoes!!). Despite the shadows of the object (that I'd need to solve manully after), this would make easier to isolate and cut objects or other photo elements.

Any thought?

Thank you a lot 🙂

Gustavo.

[c.pfaffenbichler · Accepted solution]

The Blend Mode Difference should provide a result that you can then »pump up« with Adjustment Layers. 

[c.pfaffenbichler]

By the way. Have you done a Forum search before posting? 

Because it’s not the first time someone mused about the issue. 

[Gustavo Del Vechio]

Hi @c.pfaffenbichler thank you a lot.

Yes, I did a first search this forum before posting, but did not find (so I realize I did not use right keywords)... sorry for not searching further.

Could you explain better this technique? The steps on how did you reach this result...mainly in Layers panel?

Thank you very much.

Gustavo. 

[c.pfaffenbichler]

I have myself often been incapable of finding threads that I knew existed, finding the right search terms is not always easy indeed … 

The upper layer is set to »Difference«, the Curves Layer brightens the result and the Group withing the Group has Blend if-settings. 

[Gustavo Del Vechio]

Thank you a lot!! I was able to reproduce your structure and result.

Gustavo.

[c.pfaffenbichler]

With actual photographs the inherent noise would probably make quite a bit of additional editing necessary. 

[c.pfaffenbichler]

I found threads that might be related to your question after all … 

https://community.adobe.com/t5/photoshop/is-it-possible-to-use-the-difference-blend-mode-to-create-m...

https://community.adobe.com/t5/photoshop/selecting-the-difference-between-two-images/m-p/2956153?pag...

[Gustavo Del Vechio]

Hey @c.pfaffenbichler thank you very much for the links. I'll visit and read more about! 

About your comment: "With actual photographs the inherent noise would probably make quite a bit of additional editing necessary."...

Yes, when reproducing your structure I've perceived this! The edges, for example, are not so smooth...are too sharp because, for sure, the perfect comparision of difference blend mode...and, because of this, it would need a high refinement in order to get a better result, mainly in the shadow details...

So...it's clear that various other cutting and selecting techniques and Photoshop tools would make a better work than this experiment with blend. 🙂

Thank you for sharing your expertise!

Gustavo.