With monocular vision sensor, we try to constitute a sensing system, which is able to realize self-localization, navigation and collision avoidance at the same time. This paper proposes a novel sensing system with monocular vision sensor that is placed with a certain pitch angle in the front of the robot. The vision signal obtained by the monocular vision sensor, which is partitioned into the upper and lower images. Here, we will mainly describe the effort in visual odometry using the lower half of the image. With different pitch angles in experiments, the effects on odometry accuracy are investigated and evaluated under different conditions of the reflected light.