1. A surroundings monitoring apparatus which generates a surrounding image using an image captured by a camera, said surroundings monitoring apparatus comprising: a position displacement information obtainment unit operable to obtain position displacement information which is information regarding a displacement in a position of the camera; a coordinate transformation parameter obtainment unit operable to obtain, based on the position displacement information obtained by said position displacement information obtainment unit, a coordinate transformation parameter for correcting a distortion in the surrounding image caused by the displacement in the position; an image synthesis parameter obtainment unit operable to obtain a reference image synthesis parameter which is used for generating the surrounding image using the captured image, the reference image synthesis parameter including information of image coordinates indicating, on the captured image, a pixel position corresponding to each pixel in the surrounding image; a coordinate transformation unit operable to perform coordinate transformation on the image coordinates included in the reference image synthesis parameter obtained by said image synthesis parameter obtainment unit, using the coordinate transformation parameter obtained by said coordinate transformation parameter obtainment unit, and to output the image coordinates as a transformed image synthesis parameter; and an image synthesis unit operable to generate the surrounding image by applying the transformed image synthesis parameter to the captured image, and to output the generated surrounding image.