Image processing apparatus, control method for image processing apparatus, and storage medium

An image processing apparatus processes image data generated by a reading unit configured to read a document, using at least one of a plurality of types of reading elements that have different spectral sensitivity characteristics and are cyclically arrayed in a first direction, by scanning the document in a second direction vertical to the first direction. The image processing apparatus includes a processing unit configured to perform, on the image data, filter processing for averaging pixel values of pixels at least equal in number to the types of the reading elements in the first direction, wherein the processing unit is implemented by at least one processor or at least one circuit.