Table 2.

Performance of different segmentation methods on STARE database.

Method	Average accuracy	Average sensitivity	Average specificity
Human observer	0.9354	0.8949	N/A
Hoover [4]	0.9275	0.6751	0.9567
Staal et al. [16]	0.9516	0.6970	N/A
Jiang and Mojon [22]	0.9009	N/A	N/A
Marín et al. [19]	0.9526	0.6944	0.9819
Ricci and Perfetti [18]	0.9584	N/A	N/A
Soares et al. [17]	0.9480	N/A	N/A
Akram and Khan [20]	0.9502	N/A	N/A
Wang et al. [9]	0.9521	N/A	N/A
Mendonça and Campilho [12]	0.9479	0.7123	N/A
Xiao et al. [13]	0.9476	0.7147	0.9735
Yin et al. [14]	0.9412	0.7248	0.9666
Chakraborti et al. [6]	0.9379	0.6786	0.9586
$\begin{array}{c}K=0.5\left(\text{MIN}\left({\text{Range}}_{\Phi }\right)\right)\\ \left(\text{Gray}\hspace{0.17em}\hspace{0.17em}\text{Intensity}\right)\end{array}$	0.9485	0.7458	0.9649
$\begin{array}{c}K=0.5\left(\text{MAX}\left({\text{Range}}_{\Phi }\right)\right)\\ \left(\text{Gray}\hspace{0.17em}\hspace{0.17em}\text{Intensity}\right)\end{array}$	0.9500	0.7428	0.9668
$\begin{array}{c}K=0.5\left(\text{MEAN}\left({\text{Range}}_{\Phi }\right)\right)\\ \text{(Gray}\hspace{0.17em}\hspace{0.17em}\text{Intensity)}\end{array}$	0.9504	0.7427	0.9672
$\begin{array}{c}K=0.5\left(\text{MIN}\left({\text{Range}}_{\Phi }\right)\right)\\ \left(\text{Green}\hspace{0.17em}\hspace{0.17em}\text{Channel}\right)\end{array}$	0.9457	0.7542	0.9612
$\begin{array}{c}K=0.5\left(\text{MAX}\left({\text{Range}}_{\Phi }\right)\right)\\ \left(\text{Green}\hspace{0.17em}\hspace{0.17em}\text{Channel}\right)\end{array}$	0.9500	0.7641	0.9651
$\begin{array}{c}K=0.5\left(\text{MEAN}\left({\text{Range}}_{\Phi }\right)\right)\\ \left(\text{Green}\hspace{0.17em}\hspace{0.17em}\text{Channel}\right)\end{array}$	0.9510	0.7626	0.9657