Overlap between pictures

[alialjabri]

Hello,

I am a new user of Affinity and there is a function that I cannot figure even after reading and trying a lot.

So I plan on using Affinity for image analysis on images that I obtained from a microscope. I have pictures from two groups. One group that shows all the cells in the tissue, and the other showing a specific type of cells. I am now interested in an image where only the common area between the pictures survives, I think its called masking. The purpose is to see that the cells in group two has also been stained in group one. Please let me know if I need to explain any more. 

How do I do that? I have understood that it has to do with the layer function, but I cannot put the two images on top of each other.

BR,

Ali Al-Jabri

[alialjabri]

Both pictures are white and black (binary) and what I want is a third image with only the overlap between the white areas.

[lepr]

15 minutes ago, alialjabri said:

Both pictures are white and black (binary) and what I want is a third image with only the overlap between the white areas.

If you set the upper layer's blend mode to Multiply then you will get white only where both layers are white, and everywhere else will be black.

[walt.farrell]

Welcome to the Serif Affinity forums.

1. Use File > Open to open one image.
2. Use File > Place to put the second image on top of the first image.

Or, in Affinity Photo, you could use File > New Stack to open both in one operation.

[alialjabri]

Thank you very much! Appreciated. 

[kirkt]

@alialjabri: consider using ImageJ or any of its variations (Fiji, for example).

Fiji: https://fiji.sc

It is made for image analysis and has been around for a long time.  It is free, open-source, well-maintained and cross-platform.  It also has a macro language and plug-in architecture which will permit you to automate and explicitly define the math and procedural operations you want to perform.  Chances are someone has already written a publicly-available macro or plug-in to do what you need, beyond simple blend mode layering.

Kirk

[alialjabri]

Thank you for your advice, Kirk. I already use ImageJ for the analysis of the rest of the images. It is just that ImageJ does not have a function where you can see the overlap between two images. Thats why I use a photoshop software to create this image, and then take it back to ImageJ to complete the analysis. 

 

Ali

[kirkt]

I am pretty sure it is simple math to find the intersection between two images - you can use a median filter to find or eliminate the common elements, for example.  Anyway, there are always several ways to accomplish a task, so whichever you choose will hopefully fit your workflow.  Plus, you get to try AP, which is a little different than PS, but in many ways a more modern image processing experience.

best,

Kirk