1. An image processing apparatus for use with a printed image on a moving substrate, the image processing apparatus comprising: a first imaging device configured to process spatial data which indicates a position of color patches printed along an edge portion of the printed image on the moving substrate; a second imaging device configured to process at least one of densitometric data and colorimetric data of the color patches of the printed image, wherein the first imaging device and second imaging device acquire image data from substantially the same position on the substrate at substantially the same time; and a processor configured to monitor a color of the printed image on the moving substrate based on the spatial data and the at least one of densitometric data and colorimetric data.