Both tilt information included in an image and positional information are acquired in order to calculate a relative tilt angle between at least two images. Whether the tilt information can be used to estimate the tilt angle (whether the tilt information is fake information) is determined from a distribution characteristic in the image of the acquired positional information. The tilt angle is estimated from the tilt information determined to be able to be used. A tilt included in the acquired image is corrected using the estimation result, and the image having the correct orientation can be produced.