Need help on how to cut out the similarity between two images.

[algaeman58]

Hello, I've been using the program for a decent while now, and I've been looking on how to compare two images and cut out the same parts. The context for this is that I have an image being used as a background and an image from the same position with objects in it. I can use the magic wand tool, but often times proves unwieldy for photography. If there's any answers, let me know. Cheers!

[HyReZ]

Greetings algaeman58,

 

A very useful tool for me in doing the task that you ask about; is the use of the Eraser Tool. I have used this tool to remove areas as small as 1 pixel to as large as 400 pixels. You can zoom in and out of images for pinpoint accuracy in deleting pixels. Another advantage to using the Eraser Tool is that if anti-aliasing is enabled; you will get automatic feathering of the image edge.
 

https://www.getpaint.net/doc/latest/EraserTool.html

Edited December 13, 2018 by HyReZ

[algaeman58]

2 minutes ago, HyReZ said:

Greetings algaeman58,

 

A very useful tool for me in doing the task that you ask about; is the use of the Eraser Tool. I have used this tool to remove areas as small as 1 pixel to as large as 400 pixels. You can zoom in and out of images for pinpoint accuracy in deleting pixels. Another advantage to using the Eraser Tool is that if anti-aliasing is enabled; you will get automatic feathering of the image edge.

 

HyReZ,

 

Thank you, though inefficient, it gets the job done. It would be nice if there was a faster way of doing this but it does work. 

[HyReZ]

For me it is extremely efficient as well as very effective in getting rid of artifacts that are left from using the Wand. Over time I have become very proficient in its use. I do use both tools within the same project. The are pros and cons to each as well as a time for each.

(Another useful tool with this task is the Smudge Tool)
 

Edited December 13, 2018 by HyReZ

[Ego Eram Reputo]

Here's how I'd do this;

 

Put the two images on adjacent layers. Set the top layer blend mode to Xor.

 

Differences will show up in color. Black indicates the same pixel in both layers.

 

Copy the merged image (Ctrl+Shift+C) and paste into a new layer (Ctrl+Shift+V).

 

Select all the black with the magic wand + Shift. Invert the selection (Ctrl+I) highlight the second layer & press delete.

[HyReZ]

Thank you!

 

I have never heard of this technique.

[Ego Eram Reputo]

Xor is mostly used to find differences between two images.

 

@algaeman58 I may have misinterpreted what parts you want to cut out. In the case of cutting out the same parts, don't invert the selection and cut the same out from both source layers.

[MJW]

I wrote a simple plugin that may or may not be helpful for this: Mismatch Eraser.

[NinthDesertDude]

I don't think you're talking about taking the exact differences between two identical images, but I've had a plugin for that exact purpose for a little over a year.

Download for Image Difference

 

(did I ever actually make a post for that, or have I just been hosting it on Google Drive this whole time?)

[Eli]

@Joshua Lamusga and @MJW Your plugins could be used to make disappear unwanted tourists walking infront of a monument for example 😁 Great for editing photos from your vacations!

Edited December 13, 2018 by Eli

[NinthDesertDude]

6 hours ago, Eli said:

Your plugins could be used to make disappear unwanted tourists walking infront of a monument for example 

As long as you have a picture where the tourist isn't crossing in front. I made mine to get back additions I drew on top of another image and finalized; I would do things like edit a .png file and want those edits on my .pdn source file, or Merge down some change on an image, save and close it, then later decide I want to tweak that change. So it makes it easier to isolate.

[IHaveNoName]

That sounds like a very useful plugin.

 

Up until now when I've wanted to do something like this ie. cut out a reasonably complex foreground element I've used the old photographic matte technique of creating a high contrast b/w template in another layer of the foreground elements I want to remove. That is not always easy and they often have to be retouched particularly to get the edge contours as accurate as possible but once you have that high contrast template you get a much more accurate cut out with Wizard tool. Then you can blend in the cut layer with the background.

 

The Xor technique described by Ego Eram Reputo earlier is essentially the same idea but done in a more sophisticated and unarguably, if it accurately defines the bits you want to remove, better way. I've always wondered what Xor was and could be used for.