I. Introduction
In natural world, many animals such as drosophila, moth, lobster, etc. [[1], [2]], use olfaction and vision cues to find same species, avoid predators and search for food. Those successful examples have encouraged the development of mobile robots for gas so urces localization. Existing methods of gas source localization can be categorized along two lines. One is olfaction-based methods, which mainly use olfaction to search for gas sources without visual information. The other is vision-bas ed methods, which take the visual information as an assistant of olfaction to localize gas sources.