# Applications of Smart Glasses in Applied Sciences: A Systematic Review
## 3 Results
### Product and Operating System
This product achieves an MR environment that allows interactions similar to touching an actual object based on a depth sensor equipped with artificial intelligence; further, it is not limited to industrial sites, such as construction and maintenance sites, but is also applicable to operating rooms. Epson's Moverio BT-350 is a smart glasses device that uses a reflection method applied through a waveguide-based optical fluoroscopy approach for providing information regarding digital images. Epson independently developed and used Epson light-guide technology that transmits light generated from a micro-display through a 1-cm-thick waveguide to the eye through total internal reflection. Unlike Google Glass and HoloLens, a BT-350 can be operated through a controller connected to the main unit by a wire, which can cause discomfort. Vuzix has sold blade M100 devices to a small number of companies and customers and has since steadily launched the M300, M400, and M4000 devices. This product, unlike other previous products, can be mounted on the frame of the glasses or attached to a headband. Like Google Glass, information regarding digital images can be observed through the screen in either the right or left eye. It recognizes the movement of the hands and fingers through motion sensors, which control the device. A waveguide made of plastic or glass allows the image to move between two surfaces such that the image is projected onto the eye along the interior of the lens, which is provided in the form of two fields of view, i.e., 28\({}^{\circ}\) and 40\({}^{\circ}\). An OS is a software that acts as an intermediary between users and hardware and assists in managing system hardware and running applications. Because smartphones and laptops use an OS, smart glasses also use an OS. The OSs of the smart glasses considered in this research were analyzed to understand the current state of the OSs used in research related to smart glasses. The analysis results show the difference in the OSs used based on the smart glass product (Figure 13). Thirty studies utilized the Android OS, accounting \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Item** & **Google Glass Enterprise** & **Microsoft** & **Epson** & **Vuzix** \\  & **Edition 2** & **HoloLens 2** & **Moverio BT-350** & **Blade M100** \\ \hline Storage & 32 GB & 64 GB & 48 GB & 8 GB \\ \hline CPU & Qualcomm XR1 & \multirow{2}{*}{Qualcomm Snapdragon 850} & Intel Atom X5 & \multirow{2}{*}{Quad Core ARM} \\  & 1.7 GHz Quad-core & & & \\ \hline RAM & DDR4 3 GB & 4 GB LPDDR4x system DRAM & 2 GB & 1 GB \\ \hline Battery & 800 mA-h & 16,500 mA-h & 2950 mA-h & 550 mA-h \\ \hline Camera & 8-megapixel camera & 8-megapixel camera, video recording & 5-megapixel camera, & \multirow{2}{*}{5-megapixel camera, 1080p video recording} \\ \hline OS & Android Open Source Project & \multirow{2}{*}{Windows 10} & Android 5.1 & Android ICS 4.04 \\  & 8.1 (Oree) & & & \\ \hline Weight & \(\sim\)46 g & 566 g & 151 g & 372 g \\ \hline \multirow{4}{*}{Sensor} & Wi-Fi, Bluetooth, GPS, 6-d-d-d (Degrees of Freedom), GPS & Azure Kinect sensor, accelerometer, gyroscope, magnetometer, GPS & Wi-Fi, Bluetooth, 3-axis gyroscope, 3-axis accelerometer, 3-axis magnetometer, GPS & \multirow{2}{*}{Waveguide optics} \\  & \multirow{2}{*}{Cured mirror method} & \multirow{2}{*}{Holographic waveguide} & Reflective waveguide: & \\  & Google Light pipe & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Specification of Vuzix blade [70], Google’s Glass Enterprise Edition 2 [71], Epson’s Moverio BT-350 [72], and Microsoft’s HoloLens 2 [73]. for more than half of the total number (53%). Fifteen studies employed Windows, and six papers did not mention the OS employed even when using smart glasses as devices for simple information acquisition and recording. When an OS was found, however, seven studies did not provide a specific explanation for its use. There was one case in which both the Android and Windows OSs were employed.