Patent ID: 6915026

Claim:
An image processing method of calculating, for an original image formed from a plurality of original pixels arrayed in a matrix along X- and Y-coordinate axes perpendicular to each other, a new pixel value at a desired pixel position by interpolation operation using pixel values of interpolation original pixels formed from a plurality of original pixels within a predetermined range from the desired pixel position, and interpolation coefficients corresponding to the interpolation original pixels, thereby generating a new image obtained by image-processing the original image, comprising: equally dividing a square submatrix formed from 2×2 adjacent original pixels into small square regions along the X- and Y-coordinate axes, setting approximate points at vertexes of the regions, deriving, on the basis of a predetermined interpolation function, interpolation coefficients discretized at approximate points within a predetermined range centered on an arbitrary approximate point, calculating interpolation coefficients normalized so as to adjust a sum of coefficient values of interpolation coefficients used for one interpolation operation among the interpolation coefficients to 2 k (k is a positive integer), and storing the normalized interpolation coefficients in a coefficient buffer in advance; temporarily storing an input original image in an original image buffer; calculating a new pixel position of each pixel constituting a new image in accordance with magnifications representing enlargement/reduction ratios along the X- and Y-coordinate axes for the original image; selecting an approximate point closest to the new pixel position as an approximate point of the new pixel position from approximate points in a submatrix to which the new pixel position belongs; reading out interpolation coefficients corresponding to the interpolation original pixels from the coefficient buffer on the basis of positional relationships between the selected approximate point and interpolation original pixels within a predetermined range from the approximate point; performing interpolation operation by product-sum operation between the pixel value of each interpolation original pixel read out from the original image buffer and each interpolation coefficient read out from the coefficient buffer, thereby calculating a pixel value at the approximate point; and dividing the calculated pixel value by 2 k to output a pixel value at the new pixel position.