## 3 Experimental Results and Discussion
### Development Environment of the Software and Hardware  
(1) Visual identification software development: This study uses OpenCV (open-source computer vision library), which is a library application software for computer vision and machine learning. It was originally initiated and developed by the Intel Corporation and distributed under the license of BSD (Berkeley Software Distribution license). It can be used free of charge in business and research. OpenCV includes many image processing functions, machine learning algorithms, and libraries for computer vision applications. (2) Sensors and imaging equipment:  
* Infrared thermal imaging: As shown in Figure 8, this paper uses an intermediate level infrared thermal imaging camera (TE-EQ1), which is equipped with a 50 mm fixed-focus lens with 384\(\times\)288 pixels. It can be used for mobile tracing tests with a drone flying altitude of about 100 m. The TE-EQ1 is capable of observing the distribution of heat sources in drones, providing users with drone tracing tasks through computer vision technology. * Full-color single-lens reflex camera: This study uses a Sony \(\alpha\)7 SII (Japan) with a Sony SEL24240 lens, as shown in Figure 9. The Sony \(\alpha\)7 SII features ultra-high sensitivity and an ultra-wide dynamic range. It has a 35 mm full-frame 12.2 megapixel image quality, with a wide dynamic range of ISO 50 to 409,600 and a BIONZ X processor, which optimizes the performance of the sensor, highlights details, and reduces noise, and records 4K (QFHD: 3840*2160) movies in full-frame read-out without image pixel merging, effectively suppressing image edge aliasing and moire. The main reason for choosing this device and lens is that the Sony \(\alpha\)7 SII can be transmitted via HDMI, achieving high-quality image instant transmission and less delay in camera transmission than others of a similar price, allowing instant acquisition of images and image processing. Additionally, the Sony SEL24240 telephoto single lens has a focal length of 240 mm, allowing drones at short distances (<100 m) to be clearly displayed on the tracing screen. * Thermal image acquisition: The UPG311 UVC image acquisition device is used to read the infrared thermal imaging images. The infrared thermal imaging output interface is NTSC or PAL. It is compatible with multiple systems and supports plug-and-play and UVC (USB video device class). The agreement supports an image resolution of up to \(640\times 480\) pixels. * Frame grabber for full-color camera: We used the Magewell USB Capture HDMI Gen2 capture card, which supports single-machine simultaneous connection of multiple groups of operations, and is compatible with Windows, Linux, and OS X operating systems with no need to install drivers or a real Plug and Play. It supports a completely standard development interface. In addition, the input and output interfaces use HDMI and USB 3.0, respectively, it supports an input image resolution of up to \(2048\times 2160\) and a frame rate of up to 120 fps, and it automatically selects the aspect ratio that is the most appropriate for the picture. * Laser ranger: This article uses the LRF 28-2000 semiconductor laser ranger, as shown in Figure 10. The main reason for using this laser ranger is that it uses an RF section of 900-908 nm wavelength to protect the human eye, with a range of 3.5 m to as long as 2.0 km. Its measurement resolution and measurement accuracy are 0.1 m and 1.0 m, respectively. Its specifications are suitable for the measurement of the flight altitude of the short-range drones in this study, and its significant distance measurement accuracy can be used as a basis for testing the drone flight altitude. * Multirotor: At present, the market share of multirotors is dominated by DJI Dajiang Innovation. With its drone, which is lightweight, portable, and has a small volume being sold at a friendly price, it is very popular among people generally.