Ultra-wideband (UWB) radar is considered to be a promising candidate for next-generation imaging systems in a variety of fields. The UWB radar imaging method known as SEABED (Shape Estimation Algorithm Based on Extraction of Directly Scattered Waves) has been of particular interest because of its high-speed imaging capability. This method was designed to employ a mechanical scanner that required a long measuring time, preventing real-time operation. One solution for this problem is the introduction of antenna array systems. By using an antenna array, multi-static data are obtained but cannot be effectively processed with the SEABED method because it was designed for monostatic data. A high-speed imaging method, namely Bistatic SEABED, has been proposed for UWB multi-static radar data. This method employs a reversible transform called Bistatic inverse boundary scattering transform (IBST) derived for a fixed distance between transmitting and receiving antennas. This study derives another transform, namely the common midpoint IBST, for a fixed midpoint between transmitting and receiving antennas. The performance of these methods is investigated through numerical simulations © 2012 IEEE.