Abstract: In view of the poor recognition effect of jet trajectory image caused by dense smoke occlusion, this paper proposes a jet trajectory recognition method under smoke occlusion. Firstly, the moving targets such as jet and smoke are extracted and preprocessed by the mixture Gaussian background modeling;secondly, the front jet trajectory recognition method is used to identify the front jet trajectory. The front jet trajectory recognition method includes two processes: the first is to determine whether the number of points with gray value of 255 in the adjacent column has increased dramatically to determine whether it occurs,and reserve the uncovered part; the second is to calculate the midpoint coordinates of each column of pixel value of 255 in the reserved part, and judge whether the midpoint coordinates have an upward trend. Finally, the jet trajectory equation is established, and the front jet trajectory is modified. The trajectory equation is used to replace the part of jet trajectory covered by smoke. Experiments show that the method proposed in this paper has good recognition effect.

Key words:  fire fighting, fire monitor, jet trajectory recognition;motion detection, equation fitting