Abstract: In recent years, the marine environment pollution is increasingly serious, pollution control is imminent. Investigation of sewage discharge outlets entering the sea is the first priority of pollution control. However, due to the large number of sewage discharge outlets, wide distribution, different shapes and strong concealment, conventional investigation is extremely difficult, with large investment, long cycle and many omissions. UAV aerial survey technology can quickly acquire high-resolution true color images and thermal infrared images. The color image is bright and legible, and can be directly interpreted as exposed sewage outlet. Thermal infrared is sensitive to temperature and has strong penetrability. It can identify hidden objects through temperature anomalies. The combination of the two images can effectively search the source of pollution discharge. It is a major technical breakthrough since the investigation began, and it will provide a strong technical guarantee and support for the smooth development of Marine pollution control.

Key words: outlet, UAV, thermal infrared, image inversion, image fusion