Vision based motion estimation relative to unknown terrain

A novel way to estimate the relative motion between spacecraft and surface of celestial body is introduced in this paper. When spacecraft touches down to the celestial body such as asteroids, relative motion to the surface should be detected and canceled. This paper discusses how to estimate the relative motion using monocular video camera. As no clear landmark can be expected on the celestial body, the method must be robust and applicable to a wide variety of terrain images. The algorithm introduced here takes correlation between two successive images in the frequency domain and estimate the relative motion including attitude.