1. A stereoscopic image processing apparatus, comprising: an image acquisition device for acquiring a plurality of images of an identical subject taken from a plurality of viewpoints; a corresponding point detection device for selecting a prescribed image as a reference image from among the acquired plurality of images, selecting an image other than the reference image as a target image from among the acquired plurality of images, and detecting a plurality of feature points from the reference image and a plurality of corresponding points from the target image to generate a plurality of pairs of the feature point and corresponding point, wherein feature of the feature point and the corresponding point included in the same pair are substantially identical to each other; a parameter estimation device for estimating geometrical transformation parameters for geometrically transforming the target image such that y coordinate values of the feature point and the corresponding point included in the same pair are substantially identical to each other, wherein y direction is orthogonal to a parallax direction of the plurality of viewpoints; and an image transformation device for geometrically transforming the target image on the basis of the estimated geometrical transformation parameters.