## 4 Experimental Result
### Qualitative Performance Evaluation
#### 4.2.2 Quantitative Comparison  
In this section, the performance of the method using temperature was compared with the performance of the method based on the brightness. Additionally, 14-bit digital count-based mean-shift also evaluated because it can be extracted histogram. Total histogram bin of the 14-bit digital count is the 16,384 (\(2^{14}\)). Any calibration process and image preprocessing were not included, just 14-bit raw data was used as input. The proposed TIR-MS was found to be more stable than baseline (eight-bit, 14-bit) using histogram average similarity, which is the average similarity of each histogram. In addition, the tracking accuracy was evaluated for each of the baseline and proposed TIR-MS method using the central difference and intersection over union (IOU). The central difference is an indicator of the degree of inconsistency between GT (\(BB_{GT}\)) and the target ROI pixel coordinates. Figure 10 compares baseline and the proposed in an environment when the image contrast changes due to the temperature difference between the background and target. Each video sequence was captured as a frame image when the image contrast changed with the background clutter, object variation or ROI size variations. Blue and red dotted bounding boxes are the mean-shift-based eight-bit brightness and mean-shift-based the 14-bit digital count respectively. The green box is the proposed method. Finally, the purple circle is the ground truth. It was originally the rectangle and had \(1\times 4\) matrix array including x, y, width and height of the rectangle. It has been displayed as a circle type in order to better express the ground truth since the pedestrian's head has a rounded shape. But, this is just for visualization purpose. As shown in figure 10, even though the baseline methods failed in tracking due to changes in image contrast, the proposed method succeeded in tracking all the sequences. Figure 11 shows the average histogram similarity calculated for each frame in each video sequence from Figure 10. When the temperature was used as a feature, the histogram similarity was better and more stable than when the brightness was used. The histogram similarity measure was defined as the metric distance between the candidate and target model. First, the target and candidate model are  
Figure 9: Comparison of the brightness histogram and temperature histogram. represented as a histogram model by its PDF in the feature space, as shown in Equations (11) and (12). The histogram similarity was calculated using the similarity function, as shown in Equation (13). Figure 11: Histogram average similarity of each video sequence: (**a**) average histogram similarity. Sequence (**a**,**b**), average histogram similarity (**b**,**c**), average histogram similarity (**c**). Figure 10: Video frame images of the track results were extracted using the method of the top performance using the brightness, 14-bit digital count and temperature for each sequence. The temperature data was visualized by grayscale mapping with a histogram. In the experimental results, the temperature information helps track the pedestrian head but not track using the two baseline methods: (**a**) among a total of 1146 frames, each frame was 1, 200, 450, 780, and 1020, (**b**) among total 400 frame, each frame was 1, 52, 120, 285, and 380, (**c**) among a total of 568 frames, each frame was 1, 100, 250, 400, and 560. \[\vec{q}=q_{u},\quad\sum_{u=1}^{m}q_{u}=1\qquad,u=1...m \tag{11}\]  
\[\vec{p}=p_{u}(y),\quad\sum_{u=1}^{m}p_{u}=1\qquad,u=1...m \tag{12}\]  
\[f(y)=f[\vec{q},\vec{p}(y)] \tag{13}\]  
Figure 12 presents the tracking accuracy comparing the ground truth and shows that the temperature has a smaller error rate than the brightness. The central difference is defined as the tracking accuracy between the ground truth and tracking algorithm. As shown in Equation (14), the x and y pixel coordinates values, which is a center of the ROI coordinates at the ground truth, baseline and proposed method were obtained first.