A high resolution imaging system is used to detect and locate targets using time reversal in rich scattering environments, where the number of scatterers is significantly larger than the number of antennas. Our imaging system performs two major tasks by time reversal: clutter mitigation and target focusing. Clutter mitigation is accomplished through waveform reshaping to suppress the clutter returns. After the suppressed clutter is subtracted from the returned signal, a second time reversal for target focusing is performed. A final image is then obtained by beamforming.