In order to solve the problems that Multi-scale Autoconvolution(MSA) algorithm is sensitive to an illumination change and has a large computation load

a fast scene matching algorithm combining the MSA with a direction code is presented. Firstly

the direction code images of an image to be matched and a template are computed respectively to eliminate the influence of illumination. Then the code images are blocked and the MSA value of each sub-block is calculated.So

only one row or one column of MSA value matrix needs to be updated at every searching position. In this way

the computation load has been decreased greatly

and it is less than 1/8 of that of the original MSA algorithm. Experiments are carried out with a cameramen image and real scenes. The results show that the proposed method is robust to affine transform

light projective transform

noise

occlusion and illumination change

meanwhile it has a faster searching speed and can accurately recognize and locate objects in real scenes.