Abstract: The paper gave a way to stitch the Images captured by the cameras in four different positions．Mainly,we rebuilt the grant overlook-image through calculating the relationship between the four different visual fields and overlook field．Due to the more perfect image-stitching in overlap region,based on camera calibration theory,we focused on the overlap region,recalculating the external parameters,via inverse mapping,we built the relationships from four different visual fields to overlook field．Finally,we tested the algorithm,and the result gives a proof that the algorithm is effective.

Key words: Vehicle-surrounding,Inverse perspective mapping,Overlap region,Image-stitching