Study on the Image Processing Methods for a Flame Exposed to an Incense Smoke Environment

Identification of flames to detect fires is hindered by the smoke generated from Chinese incense in traditional temples. Especially during holiday periods, smoke presents a large influence on the effectiveness of image-based flame identification. To have a deep understanding of the incense smoke impacting the flame outline, a series of tests were conducted to study the flame, varying incense smoke concentration and test time, respectively. It is found that when the flame is exposed to a thin incense smoke environment, nearly all the methods used for flame identification are effective. When the flame is surrounded by thick smoke, the flame image after treating by the self-adaptive image histogram equalization method is blurry. When the retinex algorithm is used for image treatment, the blue color near the flame is detected, which enlarges the flame area detection. The retinex algorithm can be used to obtain a clear flame outline even when the flame is exposed to a cloud of thick smoke. This is important for flame identification in the traditional Chinese temples where the thick smoke surrounds them, especially during national holiday periods. This work attempts to provide a potential method for flame identification and improve the safety level of historic buildings.