# Dog Identification Method Based on Muzzle Pattern Image
## 4 Results and Discussion
### Performance Evaluation
#### 4.2.2 Duplicate Matching Removal (DMR)  
When DMR was added to the basic method, the dog identification performance was improved for all feature extraction algorithms as shown in Table 1 (Proposed Method 1). The EER was reduced by 1.5% from 3.1% to 1.6% for SIFT, by 5.4% from 11.2% to 5.8% for SURF, by 3.7% from 14.6% to 10.9% for BRISK, and by 9.6% from 15.5% to 5.9% for ORB. ORB had the most improvement.  
The average number of good matches was reduced in both genuine matching and imposter matching compared to the basic method for all feature extraction algorithms. However, the ratio of the  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Method**} & \multirow{2}{*}{**Evaluation Item**} & \multicolumn{3}{c}{**SIFT**} & \multicolumn{3}{c}{**SURF**} & \multicolumn{3}{c}{**BRISK**} & \multicolumn{3}{c}{**ORB**} \\ \cline{3-10}  & & **Genuine** & **Imposter** & **Genuine** & **Imposter** & **Genuine** & **Imposter** & **Genuine** & **Imposter** & **Genuine** & **Imposter** \\ \hline \multirow{4}{*}{Basic Method} & Min & 4 & 0 & 4 & 0 & 29 & 10 & 12 & 8 \\ \cline{2-10}  & Max & 751 & 12 & 686 & 34 & 5791 & 622 & 2661 & 88 \\ \cline{2-10}  & Average & 132 & 4 & 96 & 6 & 1206 & 68 & 408 & 21 \\ \cline{2-10}  & False matching & 7 & 14 & 12 & 161 & 16 & 199 & 17 & 207 \\ \cline{2-10}  & Optimal threshold & 7.5 & & 8.1 & & 109.9 & & 29.7 \\ \cline{2-10}  & EER(\%) & 3.1 & & 11.2 & & 14.6 & & 15.5 \\ \hline \multirow{4}{*}{Proposed Method 1} & Min & 2 & 0 & 1 & 0 & 2 & 0 & 2 & 0 \\ \cline{2-10}  & Max & 581 & 6 & 578 & 6 & 4203 & 19 & 1214 & 14 \\ \cline{2-10}  & Average & 107 & 3 & 78 & 3 & 895 & 6 & 222 & 4 \\ \cline{2-10}  & False matching & 2 & 4 & 12 & 5 & 12 & 134 & 11 & 7 \\ \cline{2-10}  & Optimal threshold & 4.8 & & 4.6 & & 8.8 & & 9.8 \\ \cline{2-10}  & EER(\%) & 1.6 & & 5.8 & & 10.9 & & 5.9 \\ \hline \multirow{4}{*}{Proposed Method 2} & Min & 7 & 1 & 2 & 0 & 1 & 1 & 3 & 0 \\ \cline{2-10}  & Max & 889 & 6 & 822 & 6 & 3787 & 29 & 2180 & 21 \\ \cline{2-10}  & Average & 181 & 4 & 120 & 3 & 709 & 6 & 685 & 6 \\ \cline{2-10}  & False matching & 0 & 0 & 7 & 18 & 14 & 193 & 2 & 28 \\ \cline{2-10}  & Optimal threshold & 6 & & 4.7 & & 8.3 & & 12.3 \\ \cline{2-10}  & EER(\%) & 0 & & 5.8 & & 12.7 & & 1.8 \\ \hline \multirow{4}{*}{Proposed Method 3} & Min & 8 & 0 & 4 & 1 & 9 & 0 & 82 & 0 \\ \cline{2-10}  & Max & 670 & 8 & 311 & 6 & 1061 & 26 & 1740 & 25 \\ \cline{2-10}  & Average & 189 & 4 & 76 & 3 & 346 & 5 & 725 & 6 \\ \cline{2-10}  & False matching & 0 & 0 & 1 & 0 & 1 & 12 & 0 & 0 \\ \cline{2-10}  & Optimal threshold & 8 & & 5.7 & & 18 & & 25 \\ \cline{2-10}  & EER(\%) & 0 & & 0.9 & & 0.9 & & 0 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Results of performance evaluation of the matching methods.  
decreases was much larger in imposter matching than in genuine matching. The large decrease of incorrect matches in imposter matching reduced the false matches and resulted in the reduction of the EER. This result showed that the proposed technique, DMR, was effective for the improvement of the dog muzzle pattern recognition.