— Safe navigation through corridors plays a major role in the autonomous use of Micro Aerial Vehicles (MAVs) in indoor environments. In this paper, we present an approach for wall collision avoidance using a depth map based on optical flow from on board camera images. An omnidirectional fisheye camera is used as a primary sensor, while IMU data is needed for compensating rotational effects of the optical flow. The here presented approach is designed for safely maneuvering a helicopter through an indoor corridor. Results based on real images taken in a corridor with textured walls are shown at the end of this paper.