1. An image processing apparatus comprising: an image acquisition unit that acquires a first image and a second image each of which includes a character string; an extraction unit that extracts feature points included in each of the first image and the second image; a setting unit that sets one or a plurality of partial regions including a plurality of characters which are continuously arranged in an arrangement direction of the character string in each of the first image and the second image; and a specification unit that compares positions of the feature points included in the partial regions set in the first image by the setting unit with positions of the feature points included in the partial regions set in the second image by the setting unit so as to specify the partial regions set in the second image corresponding to the partial regions set in the first image, and specifies corresponding points in each of the specified partial regions.