An automatic registration algorithm between infrared and visible images based on step estimation of affine model parameters is proposed.Firstly

the six degrees of freedom of the affine model are separated into some more easily estimated parameters using matrix orthogonal decomposition method

which are skew

scale ratio

rotation

scaling and translations in

x

and

y

directions.Secondly

two objective functions are constructed for step estimation of these parameters based on the orientation consensus constraint and alignment measure between segments

respectively

and parameter values which make objective function approximate the global optimum are o

btained using SGA (Stud Genetic Algorithm) algorithm.Finally

the estimated values of the parameters are locally refined using Powell algorithm.The experimental results show that the proposed method can make full use of orientation consensus constraint and location distribution information of segments

and realize automatic registration between infrared and visible images efficiently and precisely on condition that two images to be registered contain abundant corresponding segments and diverse distributions of segment orientations.