1. A surroundings monitoring apparatus which generates a surrounding image using an image captured by a camera, the 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 the position displacement information obtainment unit, a coordinate transformation parameter for correcting a distortion in the surrounding image caused by the displacement in the position, the coordinate transformation parameter defining a function for transforming two-dimensional coordinates of one pixel into two-dimensional coordinates of another pixel; an image synthesis parameter obtainment unit operable to obtain at least one reference image synthesis parameter which is used for generating the surrounding image using the captured image, the at least one 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, and the image coordinates being two-dimensional coordinates; a coordinate transformation unit operable to perform coordinate transformation on the two-dimensional image coordinates included in the at least one reference image synthesis parameter obtained by the image synthesis parameter obtainment unit, using the coordinate transformation parameter obtained by the coordinate transformation parameter obtainment unit, and to output the image coordinates as a transformed image synthesis parameter indicating transformed two-dimensional image coordinates; 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, wherein the image synthesis unit is operable to read, from among pixels included in the captured image, an image of a pixel located in the transformed two-dimensional image coordinates indicated by the transformed image synthesis parameter, and to output the read image as an image of a pixel located in the surrounding image and corresponding to the pixel located in the transformed two-dimensional image coordinates.