Inverse Scattering from a Sound-Hard Crack via   Two-Step  Method

<table class="table-group" width="800px"><tr class="fig-image" id="a"><td><img alt="810676.fig.003a" src="https://static.hindawi.com/articles/aaa/volume-2012/810676/figures/810676.fig.003a.jpg"/></td></tr><tr class="fig-caption"><td align="center"><table><tr><td><b>(a) </b>Exact data, <svg height="11.375" id="M137" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 50.724998 11.375" width="50.724998" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg></td></tr></table></td></tr><tr class="fig-image" id="b"><td><img alt="810676.fig.003b" src="https://static.hindawi.com/articles/aaa/volume-2012/810676/figures/810676.fig.003b.jpg"/></td></tr><tr class="fig-caption"><td align="center"><table><tr><td><b>(b) </b>3% error, <svg height="11.375" id="M138" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 50.724998 11.375" width="50.724998" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,0,0,-.017,.062,11.113)"><path d="M857 650l-6 -28q-44 -4 -61.5 -16.5t-29.5 -48.5q-11 -32 -37 -166l-78 -399h-29l-351 537h-4l-56 -276q-24 -120 -24 -164q0 -35 17.5 -46t75.5 -15l-6 -28h-245l7 28q41 2 62 14t31 44q10 30 41 171l53 245q8 44 6.5 60.5t-14.5 33.5q-10 15 -27 19.5t-64 6.5l6 28h153
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Abstract and Applied Analysis

Inverse Scattering from a Sound-Hard Crack via Two-Step Method

Figure 3