A novel imaging system based on nondiffracting X waves

Nondiffracting beams have been suggested for ultrasonic imaging because of their long depth of field. Recently, a new class of nondiffracting beams, termed the X waves, has been discovered. A new pulse-echo system employing the X waves is proposed. In the theoretical model of the system, a position-dependent filter is employed to produce the nondiffracting field on the aperture. A similar filter is used to process the received echoes. Analytical expressions for the point spread function (PSF) and the transfer function of the system are derived. The PSF of this system is space-invariant, providing uniform resolution throughout the image area. In practice, the system can be implemented employing an annular array transducer and a set of filters. Results based on simulated B-mode images, are presented, indicating that high resolution, large depth of field images can be obtained by this system