Fig. 2.

The single-sheet backpropagation (SSB) method for 3D reconstruction from a single surface pressure map. (a) Each row illustrates that the wave having a same lateral spatial frequency $\mathbf{q}$ can be decomposed with multiple plane waves having different propagation constant $\beta$’s (different columns). (b) Temporal frequency spectra of surface pressure maps obtained with a line-shaped PET fiber embedded in PDMS. (c) The spectrum (blue solid line) averaged along the direction ($y$-direction) of the PET fiber and fitted with a parabola (red dotted curve). (d) Maximum intensity projection images of a knot-shaped phantom reconstructed using 1, 3, and 20 surface pressure maps with the proposed SSB method, and (e) a 3D view reconstructed using 20 maps. (f) For objects located crosswise with a depth difference of 1 mm, a depth-selective thin-volume image was reconstructed by using a single pressure map (first, second) taken at different times, and the full-volume image by using 40 pressure maps (third). (g) The 3D view reconstructed using 40 pressure maps. Scale bars in (d)-(g): 1 mm.