Method and apparatus for adaptively interpolating a digital image

Abstract

Digital image processing apparatus for interpolating a digital input image into an interpolated output image, in one embodiment of the invention, comprises an input buffer (12) for accommodating pixel data of the input image and a coefficient buffer (14) for storing precalculated interpolation weighting coefficients prior to real time image interpolation. The coefficient buffer (14) comprises a first memory segment (22) for containing a set of precalculated sharp interpolating weighting coefficients obtained by using a sharp interpolating algorithm, a second memory segment (24) for containing a set of precalculated soft weighting coefficients obtained by using a soft interpolating algorithm and a third memory segment (26) for containing a set of precalculated weighting coefficients representative of a predetermined characteristic of the input image, such as contrast or density. The processing apparatus further comprises interpolation logic (16) for calculating a sharp interpolated output image pixel, a soft interpolated output image pixel, and a value for the image characteristic, using the input pixel data and the precalculated weighting coefficients, and an algorithm implementation controller (18) for calculating a resultant output pixel by combining the sharp and soft interpolated pixel values as a function of the image characteristic.