1. An image processing apparatus, comprising: a detector configured to form one group with pieces of pixel information on an edge of a received image, detect line segments, and generate a plurality of curves using the detected line segments; an optimizer configured to apply a weight to a cost function based on the plurality of generated curves according to a distance from a center of the image, define an outlier and an inlier, remove the outlier, and estimate a distortion level parameter; and a corrector configured to correct a position of a pixel with a correction value using the distortion level parameter.