A Survey on Breaking Technique of Text-Based CAPTCHA

<table class="figure-group"><tr class="fig-image" id="a"><td><object data="https://static.hindawi.com/articles/scn/volume-2017/6898617/figures/6898617.fig.002a.svgz" name="6898617.fig.002a" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(a) </b>Original three-color bar</td></tr><tr class="fig-image" id="b"><td><object data="https://static.hindawi.com/articles/scn/volume-2017/6898617/figures/6898617.fig.002b.svgz" name="6898617.fig.002b" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(b) </b>Denoised three-color bar</td></tr></table>

<div>Three-color bar corresponding to CAPTCHA image.</div>

Security and Communication Networks

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Figure 2

Figure 2: A Survey on Breaking Technique of Text-Based CAPTCHA 