## 4 Experimental Result
### Qualitative Performance Evaluation
#### 4.2.2 Quantitative Comparison
The parameters \(x_{gt}\) and \(y_{gt}\) were then subtracted from the x and y values of the baseline and the proposed method, respectively. Finally, the absolute value of the total equation was obtained. \[d(x,y)=|x-x_{gt}|+|y-y_{gt}|. \tag{14}\]  
The intersection over union is defined as the size of the intersection divided by the size of the union of the ROI sets. As shown in Equations (15) and (16), A and B are ROI coordinates of ground truth and the tracking algorithm. The coordinate of upper left corner be (\(x_{l}\),\(y_{l}\)) and bottom right corner be (\(x_{r}\),\(y_{r}\)). The IOU, which measure dissimilarity between ground truth and tracking algorithm, is calculated by dividing the difference of the sizes of the union and the intersection of two sets by the size of the union, as shown in Equation (17). \[A=[x_{l}\,y_{l}\,x_{r}\,y_{r}]_{gt} \tag{15}\]  
\[B=[x_{l}\,y_{l}\,x_{r}\,y_{r}] \tag{16}\]  
Figure 9:0  
Figure 9:1 Central difference of each video sequence: (**a**) central difference (Figure 11a), (**b**) central difference (Figure 11b), (**c**) central difference (Figure 11c). Figure 13 presents the intersection over union which is the most popular evaluation metric used in the object tracking accuracy between ground truth and tracking method. Tables 3 and 4 list the tracking performance of each of the average similarity and central difference baseline (eight-bit, 14-bit) and proposed (TIR-MS) in the video sequence when the image contrast and target changes. For each of the eight-bit and 14-bit baseline, the standard deviation of the histogram average similarity of the entire video sequence was each 0.0101 and 0.00112, respectively. However, the standard deviation of the TIR-MS method was 0.0039, as shown in Table 3, which suggests that two baseline methods are more unstable than proposed. In addition  
Tables 5 and 6 list the tracking accuracy and speed of each of the intersection over union (IOU) and frame per second (FPS) baseline (eight-bit, 14 bit) and proposed (TIR-MS) in the video sequence when the image contrast and target changes. For each of the eight-bit and 14-bit baseline, the standard deviation of the IOU of the entire video sequence was each 0.142 and 0.155, respectively. Also, the mean of the two baseline methods was each 0.513 and 0.498, as shown in Figure 9:2 However, the mean and standard deviation of the proposed method were 0.656 and 0.103, respectively, which suggests that two baseline methods were more unstable than proposed. In addition, Table 6 shows that FPS value of the proposed method are larger than that two baseline methods in all video sequences, which indicates that the proposed method has higher tracking speed than two baseline. Additionally, 14-bit digital count had 16,384 total histogram bin range and it records the lowest FPS rate, as shown in Figure 9:3 This suggests that FPS rate is depending on the histogram bin range. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Algorithm** & \begin{tabular}{c} **Baseline** \\ **(8-bit)** \\ \end{tabular} & \
\begin{tabular}{c} **Baseline** \\ **(14-bit)** \\ \end{tabular} &
\begin{tabular}{c} **Proposed** \\ **(TIR-MS)** \\ \end{tabular} \\ \hline S1 & 31.32 & 10.87 & 33.52 \\ S2 & 33.02 & 9.225 & 34.89 \\ S3 & 34.24 & 11.41 & 35.91 \\ S4 & 27.72 & 8.142 & 29.81 \\ S5 & 32.09 & 10.34 & 33.12 \\ S6 & 28.08 & 9.562 & 30.97 \\ S7 & 26.91 & 7.881 & 28.71 \\ S8 & 26.13 & 8.023 & 27.84 \\ \hline
**Mean** & 29.94 & 9.431 & 31.85 \\
**STDEV** & 3.084 & 1.359 & 2.952 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison of tracking speed: frame per second (FPS).