Electromagnetic Induction Imaging of Metallic Objects at Multiple Depths

In this letter, a novel approach is presented for imaging of metallic objects based on induction sensing. The approach relies on the concept of collection of the point-spread function (PSF) in a linear space-invariant system. For this purpose, the responses of small objects are measured a priori to serve as the PSFs of the imaging system. Then, these PSFs are employed in a test scenario in which the responses of unknown objects distributed over multiple depths are measured and inverted to reconstruct two-dimensional (2-D) images at those depths. The stack of these 2-D images provides a 3-D image. The image reconstruction is fast due to the use of forward and inverse Fourier transforms. This imaging approach is validated via the use of off-the-shelf components.