WO2008059229A3 - Alias avoidance in image processing - Google Patents

Abstract

Image processing apparatus in which output pixel values are generated with respect to pixels of an input image selected in accordance with an image feature direction in the input image comprises comparing means for comparing blocks of pixels of the input image, the blocks being disposed with respect to a pixel position under test so that a correlation between the blocks would indicate an image feature direction applicable to that pixel position; and validating means, operable in respect of an image feature direction detected by the comparing means in respect of the pixel position under test, for detecting whether that image feature direction may be used to interpolate an output pixel value at that pixel position, the validating means being arranged (i) to detect whether the detected image feature direction is similar to image feature directions applicable to n image regions, where n > 1, disposed with respect to the pixel position under test; and (ii) to validate the image feature direction for the pixel position under test for use to interpolate an output pixel value at that pixel position if the detected image feature direction is similar to image feature directions of at least a predetermined number m, where m < n, of the image regions.