Image resampling with adaptive sharpening

-50 IMAGE RESAMPLING WITH ADAPTIVE SHARPENING A method (Fig. 6) for processing an image comprising input samples located on a 5 regularly spaced grid to produce an output image comprising output samples. The method estimates an isophote orientation (6010) based on a location of an output sample and locations of input samples close to the location of the output sample, and selects (6040), based on the estimated isophote orientation, a directional sharpening filter (6050,6060) having a corresponding sharpening direction. The output of the selected 10 sharpening filter (6050) includes directional frequencies beyond the Nyquist limit determined by a sampling rate of the input samples in a direction of the selected sharpening filter. The method applies the selected sharpening filter to input samples located about the location of the output sample to produce a plurality of sharpened samples (6070) and combines (6080, 7080) the sharpened samples (6080) to produce an 15 output sample at the output sample location based on the location and the isophote orientation. 2453925_1 930061_specilodge start Determine local isophote 6010 6000 orientation Determine reliability of the isophote 6020 orientation 6030 6040 6050 Is yes sophote yes Select vertical orientation predominantly sharpening filter reliable? orizontal no no Select horizontal sharpening filter Calculate default Calculate sharpened 6070 output sample samples using using default selected filter filter Combine sharpened 6080 samples to produce one anti-aliased sample Fig. 6 9Ar.;AO1' 1 930061 fias lodae