The study of UWB (Ultra Wide-Band) pulse radar has attracted great interest in a variety of applications including surveillance systems. The high-speed SEABED (Shape Estimation Algorithm based on BST and the Extraction of Directly scattered waves) imaging algorithm, is a promising candidate for the application of UWB pulse radar in fields that require real-time operation. However, since the SEABED algorithm uses signals received at multiple locations, it can only be used in systems with either array antennas or a mechanically-scanned antenna. Such systems are inevitably costly and unrealistic for applications such as surveillance. To overcome this problem, a revised SEABED algorithm was developed, which relies on the motion of the target instead of scanning an antenna. This imaging method works with only a pair of fixed antennas, even for a target with unknown shape and motion. The method cannot, however, be applied to arbitrary motion, because it assumes that the target is located on a straight line parallel to the baseline of the pair of antennas. In this paper, we extend the revised SEABED algorithm so that an accurate imaging can be achieved when applied to arbitrary target motion.