Mirror-image perception is the human tendency to see oneself (especially while in the throes of conflict) as the opposite of the person with whom they are having a conflict. They are mutual and reciprocal views of others.
For instance, two neighbors are having an argument about some disruptive neighborhood problem. In this case, both neighbors may see themselves as the good and reasonable one while the other is disruptive and argumentative. Two groups at war may both simultaneously view themselves as the just, moral heroes in the scenario while viewing the others are amoral, cruel, and evil.