## 4 Experiments and Performance
### Experimental Results and Analysis
#### 4.2.1 Experimental Validation of MSS-YOLO-Based Miner Identification
Specifically, a cutting dust simulator (A-1000, manufactured by JC Light, Guangdong, China) and a mobile power supply (DC12-24 V, manufactured by CARWANTA, Guangdong, China) were used to replicate a dust-laden environment. With reference to the actual camera arrangement in a fully mechanized mining face, a ZED2i binocular camera was installed on top of the hydraulic bracket. Meanwhile, a digital total station (FX201, Manufactured by SOKKIA, Saitama, Japan) was used to measure the center of the personnel in order to obtain their three-dimensional spatial coordinates under the total station's coordinate system. The entire experiment was carried out on a platform, as shown in Figure 16.  
In the experiment, the main parameters of the SGBM binocular stereo vision matching algorithm used in this paper were as shown in Table 3. In order to ensure the feasibility of the described method, the experiment was divided into 20 groups for experimental verification according to the dust concentration, personnel distance, and the number of personnel. Among them, groups 1-12 comprised a single person with different concentrations and at different distances up to 10 m from the camera, and groups 13-20 comprised two people at different concentrations and at different distances up to 10 m from the camera. At the same time, in order to unify the coordinate system of the total station and binocular camera and to facilitate the comparison of the positioning results, with the help of the checkerboard, we utilized the position information of the four boundary points of the checkerboard under the left view of the digital total station and binocular camera as the intermediate conversion quantity. Furthermore, we solved the left view of the binocular camera to obtain the rotation matrix R for the total station and the displacement vector T by using PnP (Perspective-n-Point) in order to convert the results obtained by the binocular camera to the total station coordinate system. In this paper, the total station data were taken as the actual true values, and the analysis of the identification and localization results and errors for the 20 groups of people is shown in Table 4. \begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**Parameter** & **minDisparity** & **numDisparities** & **blockSize** & **speckleWindowSize** & **Mode** \\ \hline Value & 1 & 512 & 9 & 100 & STEREO\_SGBM\_MODE\_HH4 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Values of the main parameters of the SGBM algorithm. Figure 16: Experimental platform for binocular visual localization of miners in the fully mechanized mining face. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \multirow{2}{*}{**Groups**} & **Total Station Data** & \multirow{2}{*}{**Camera Data (xyz)**} & \multicolumn{2}{c}{**X-Direction Error**} & \multicolumn{2}{c}{**Y-Direction Error**} & \multicolumn{2}{c}{**Z-Direction Error**} & \multicolumn{2}{c}{**Practical**} & \multicolumn{2}{c}{**Measuring**} & \multicolumn{2}{c}{**Distance Error**} \\  & **(xyz)** & & **(m)** & **(m)** & **(m)** & **(m)** & **Distance (m)** & **Distance (m)**  
As shown in Table 4, the x- and y-directions have high position measurement accuracy, while the position measurement error in the z-direction is large. In the measurement range of 3-10 m, the measurement errors of the positions in the x-, y-, and z-directions are within 0.170 m, 0.160 m, and 0.200 m, and the average errors are 0.014 m, 0.008 m, and 0.043 m, respectively. At the same time, from the point of view of the measurement distance, the distance measurement error is within 0.185 m, which meets the maximum error for personnel positioning in the coal mine working face. The influence of the positioning method described in this paper on the measurement accuracy of miners in the fully mechanized mining face is shown in Figure 17.  
As can be seen from Figure 17, the measurement error of the method described in this paper is mostly within 10% of the actual true value in the x-, y-, and z-axes, which shows good robustness.