A document camera (1) detects a figure of a known shape on a stage (13) and acquires the coordinates of the figure, and acquires image processing area and projection correction parameter. The document camera (1) extracts image data of the image processing area from image data acquired by shooting the stage (13) and an original (4), and performs projection correction on the image data using the projection correction parameter. Further, the document camera (1) performs rotation correction on image data undergone projection correction. Furthermore, the document camera (1) performs zoom correction on image data undergone rotation correction, and generates output input image.