## 3 Perception Sensors for the UGV Detection System
### Vision System  
The daylight-thermal observation system is a vehicle camera composed of a thermal camera and a color daylight camera with a 60\({}^{\circ}\) horizontal field of view. The device is designed for tactical operation during day or night under clear or obscured atmospheric conditions such as fog or smoke. The thermal module incorporates an uncooled bolometric detector with a resolution of 640 \(\times\) 480 pixels (Figure 4). The system is controlled via an RS-485 link and has two independent video outputs (Table 1) in PAL standard [18].  
Camera windows are equipped with a deicing function. Sensors can be mounted on vehicles or other objects to provide driver vision enhancement, situational awareness, or observation during day and night-time.  
For testing purposes, the vehicle was also equipped with a ZED 2 stereo camera. This vision system is designed for use in unmanned vehicles and augmented reality applications. It provides high-resolution, high-quality 3D imaging and depth-sensing capabilities. The camera produced by Stereolabs captures stereo video and depth data using two ultra-wide-angle sensors and a proprietary algorithm, allowing for object and surface detection in real time, even under low-light conditions. This information can be used to create 3D models of the environment, track the movements of objects and people, and support various other applications in the fields of autonomous vehicles.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Thermal Camera (IR)** & **Daylight Camera (TV)** \\ \hline Field of view (horizontal) & 60\({}^{\circ}\) & 60\({}^{\circ}\) \\ Detector & Uncooled bolometric FPA & 1/3\({}^{\prime\prime}\) CMOS \\ Resolution & 640 \(\times\) 480 px & 1920 \(\times\) 1080 px \\ Spectral response & 8 \(\upmu\)m to 12 \(\upmu\)m & - \\ \hline \hline \end{tabular}
\end{table}
Table 1: Main parameters of the daylight–thermal and observation cameras.  
Figure 4: View of the daylight–thermal camera.  
In addition to its stereo imaging capabilities, the ZED 2 camera also offer advanced computer vision algorithms, such as depth perception, object detection, and semantic segmentation.  
The main parameters of the ZED 2 camera are listed below [19]:  
* Resolution up to 2K (2048 \(\times\) 1024 pixels);
* Field of view of over 200 degrees;
* Depth resolution of 720p (1280 \(\times\) 720 pixels) and depth accuracy of up to 2 cm;
* Frame rate of up to 60 frames per second (fps);
* Latency of less than 10 milliseconds between capturing an image and processing the data;
* Image format: the stereo video output is in YUV format, while the depth data are output as 16-bit grayscale.  
There are several limitations of camera usage for unmanned ground vehicles related to lighting conditions (clear and accurate images), as well as weather conditions such as rain, snow, or fog, which can reduce accuracy and effectiveness. In relation to the operational environment of the TAERO vehicle, cameras may encounter challenges in detecting certain obstacles, especially if they are small or have low contrast with the background. Despite some applications for which only vision-based sensors be used in autonomous mode, it is necessary to use additional technologies in order to increase the accuracy and reliability of the perception system for unmanned operation.  
Integrating cameras with other sensors, such as radar or LiDAR can provide a more complete and accurate understanding of the environment. These additional sensors can detect objects and obstacles that are difficult or impossible to see with cameras alone, improving the overall accuracy and reliability of the perception system.