Has duplicate #36601.
Your question doesn't appear to be a bug report about any MacPorts port, but rather a question about how to use MacPorts ports together with your own software in /Users/alexluleme/Desktop/Master_Visual_Homing/examples/find_obj_video. It looks like that program was compiled with an older version of opencv. Now that the opencv port has been updated to a newer version, it provides a newer version of the library. You'll need to recompile your program to link it with the new library. If that doesn't work or is not possible, then another option would be to downgrade the opencv port back to a previous version.
For further questions about how to use MacPorts with your own software, please write to the macports-users mailing list. The issue tracker is for bug reports and feature requests regarding MacPorts ports.