Quasi-wavefront selection algorithm for fast and accurate ultra-wideband imaging with polar revised range point migration

Ultra-wide-band sensing is an important technology for imaging in situations where conventional camera-based systems are difficult to use because of dense smoke or steam. Although many applications of such systems require real-time operation, conventional imaging algorithms cannot satisfy this demand, because most methods have focused on the imaging quality alone. Recently, a fast imaging algorithm, called polar revised range point migration (PRRPM), was developed that enabled the target images to be obtained within a short time. The PRRPM uses a closed-form transform called the polar inverse boundary scattering transform (PIBST), which expresses the relationship between the signal delay time and the target images. Although the PIBST was shown to be capable of producing images quickly, the images were degenerated because of wrongly estimated delay times, especially if the fractional bandwidth was narrow, and generated ringing waveforms with multiple false peaks. In this paper, we propose a method to select the correct delay times among multiple peaks that were estimated using the conventional method, which suppresses the false images caused by the ringing components. The proposed method is applied to measurements with m-sequence radar to establish the performance of the method.