Vision-based robot navigation systems allow a robot to explore and to navigate in its environment in a way that facilitates path planning and goal-oriented tasks. The vision sensor is mainly used for obstacle detection and avoidance, object detection and tracking, and interaction with users. Usually these systems do not depend solely on vision sensors but use other sensors like sonar and laser range finder. The paper considers an important issue for mobile robots navigation. This issue is the detection of obstacles in front of the robot within a corridor. We proposed and evaluated three algorithms for obstacle detection within a corridor environment using image processing techniques