1. An image processing method, comprising: generating rectification information by performing rectification on input images with different viewpoints based on calibration information and the input images; calculating an information loss of cropped images for the input images, the cropped images being obtained by cropping performed concurrently with the rectification; calculating a motion vector of points corresponding to the input images when the information loss is greater than or equal to a value, the calculating the motion vector being based on homography information and disparity information on the input images, the homography information being based on the calibration information and the rectification information on the input images; and generating a new viewpoint image from the input images based on the motion vector when the information loss is greater than or equal to the value.