# A Drone-Enabled Approach for Gas Leak Detection Using Optical Flow Analysis +
## 1 Introduction
All the reviewed surveys emphasize the consequences and prevalence of gas leak detection methods demonstrating the importance of finding reliable techniques as an essential preventive measure. In order to decrease the risks and potential product loss, industries rely on accurate and reliable reports and analyses prepared by experts for detecting the issues and maintain the systems. Therefore, providing the tools and automation processes can assist inspectors in providing more reports with less human error in a more satisfying time frame. Additionally, since the corrective measures require more extensive information about the leakage such as origin, severity, and size, recent studies also are focused on providing comprehensive approaches to detect and characterize gas leaks. One of the fundamental requirements for an effective corrective measure is the identification and quantification of the leaks like the level of gas concentration and approximation of the source's location. Therefore, the proximity of equipment or inspectors to the possible leaks increases the reliability of the analysis. Conventional inspection approaches for gas leak detection requires direct contact of inspectors with the environment. Due to the hazardous nature of these gases, an inspection of these sites can put the personnel at considerable health risk. In addition, likely access constraints imposed by the conditions like height or temperature of an operating facility can make the inspection very challenging or even impossible. The challenges and requirements motivated companies to use flexible and mobile units to carry on the inspections. Ground-vehicles equipped with gas analysis technologies can certainly increase the reliability and safety of such inspections. However, in many scenarios, it is very hard or impossible for them to reach the emission source because of the height or complex structure of the component. Using unmanned aerial vehicles for the inspections can decrease the risk as well as the cost and time of the operation. The maneuver capabilities provided by drones can assist inspectors with better access to the facilities and reduce the inspection time, which can motivate the companies to perform them more regularly. Moreover, this approach minimizes the number of required staff on-site, which can also lead to cost- and time-saving and an increase in operational safety. Therefore, introducing drone-enabled techniques for the detection and characterization of gas leaks is very essential and is the main motivation behind this study. In this paper, we introduce an approach to enhance the visibility of possible gas leaks in recorded image streams using image flow analysis. Moreover, we investigate the possibility of locating the origin of possible gas leaks based on gas concentration. One of the issues in the analysis of drone-recorded image streams is the rigid motion of UAVs during hovering, which can diminish the usability of the recorded image streams. In this paper, we investigate the use of video stabilization methods for minimizing the effect of such motions. The organization of this paper is as follows, The literature review and a survey about the current methods of gas leak detection are presented in Section 2. The video stabilization and gas leak detection techniques are described in Sections 3.2 and 3.3 respectively. Moreover, the experiments and results are presented in Sections 4 and 5. Finally, the conclusion of this work is presented in Section 6.