关键词: MSA火灾报警系统, 双灭点, 透视校正

Abstract: Image based fire detection system is one of the most important factors of MSA（Multi-Step-Alarm） fire warning system，in which the precise location of fire is one of the most important missions.By the reasons of practical application such as allocation of monitor，the parameter of the transformation is difficult to get.In this paper，a method of perspective projection transform based on double vanishing point is proposed，which is able to transform image coordinate into world coordinate by analyzing the locations of four control points.Experiment results show the method is reliable and valid.

Key words: Multi-Step-Alarm（MSA）, double vanishing point, perspective projection rectification