An apparatus comprises supply means for changing an amount of light sinusoidally and supplying to a projection means a patterned light signal for sequentially projecting on an object to be measured at least three patterns of patterned light having phase differences; obtainment means for obtaining image data acquired by capturing the object; first generation means for generating a phase image from image data acquired by capturing the object on which the patterned light is sequentially projected; second generation means for generating, based on the phase image, a shape image which indicates a distance between a surface of the object and a viewpoint in the capturing; and correction means for calculating an amount of correction for the shape image from a correspondence between a pixel value of a high-frequency shape image indicating a high-frequency component of the shape image and a pixel value of the phase image.