Interpolation device

An interpolation process for scaling is performed directly on raw data from an image pickup apparatus. Raw data, constituted by inputted Bayer pattern array are as a set of pixels positioned on respective lattice points on a square lattice. A position of an interpolation point Q is designated by an upper address that indicates a lattice point near the upper left and a lower address that indicates a position inside a lattice frame, a specific color is designated for which a pixel value is to be determined. An interpolation reference frame is determined, formed of a smallest square, which contains the interpolation point Q and with which the four vertices are formed by lattice points of the designated color, and an interpolation origin, constituted by the upper left lattice point of the interpolation reference frame, interpolation proportions d* and e* are determined. An interpolation calculation is performed.