Fig. 1: Working principle of a 2D spatial differentiator for isotropic edge-enhanced imaging.
From: Compact meta-differentiator for achieving isotropically high-contrast ultrasonic imaging
Schematic of the imaging process in (a) a conventional imaging system and (b) an edge-enhanced imaging system. The input image, acoustic metasurface, and the output image are positioned at different planes: z = −f, z = 0 and z = f, respectively. The insets in (a) and (b) show the amplitude and phase profiles imparted onto the acoustic metasurface. c Illustration of the spatial wavevector redistribution mechanism for the 2D spatial differentiation operation.
