Figure 9.

Images of the channel using sparse aperture data. Reconstructions by SAFT using (a) 14.06% sparse data and (d) 6.25% sparse data. Reconstructions by the SDUI method with ${\lambda }_2=0$ using (b) 14.06% sparse data with ${\lambda }_1=20$ and (e) 6.25% sparse data with ${\lambda }_1=5$. Reconstructions by the SDUI method using (c) 14.06% sparse data with ${\lambda }_1=600$, ${\lambda }_2=20$ and (f) 6.25% sparse data with ${\lambda }_1=250$, ${\lambda }_2=10$. All dimensions are in millimeters.