Grzmocislaw

Thank you @NathanC, @NotMyFault and @thomaso for answering my question.

At @thomaso
 
It is not about the color itself, I want to mask the background so my photogrammetry software will not use it for the calculations. Therefore, only the tower will be used. 
As you can see in the image, the tower is red and white with grey colour for the antennas. 


At @NotMyFault
 
 Actually, what you showed in the image looks very promising. If most of the background is removed apart from the dark strip at the top of the picture, this may be enough to force the program to use only pixels from the tower. Therefore, my goal would be achived, even if the photo is not 100% masked.



 
Is the above the way you achieved the image you posted? I will do some resarch and I will try to recreate your process to see if I understand it well.

 
 
 
As for the AI, what you wrote is exactly what I was thinking myself. Unfortunately, without the knowledge of coding, it may be extremely difficult, so I would like to stick with regular programs and automatic/batch processes.