Camera motion filtering is important in many applications, such as camera-based visual control interface on a mobile device. In this paper, we first present a robust global motion estimation algorithm based on optical flow and RANSAC, and a strategy that decompose camera motions into individual components frame-by-frame. A motion filtering strategy is then proposed to detect the most dominant motion within each individual component. Acceleration strategies are proposed to make it run real-time. Applications in video analysis and a mobile visual control interface are discussed.