How to reject clutters or background while detecting the Man Made Objects in the natural images with grass and trees?

Hello everyone,

Could anyone helps me or explains how to reject the background of the natural images in order to detect Man Made Objects and draw the a line around the objects boundaries. It differs from detecting Man Made Objects from the aerial scene. Also, if anyone has any sources or codes please kindly share :) It would be helpful to do my project.

Note: attached some pictures in the zip file to take a look for them and to to understand more about what I meant in my question.

Thank you!

Mostafa