METHOD FOR INTERPOLATION AND SHARPNESS INCREASE OF DIGITAL IMAGES

摘要

PROBLEM TO BE SOLVED: To disclose a method for interpolation and sharpness increase of digital images. SOLUTION: The method comprises a step (1) of inputting an image or graphic signal Xij to a first interpolation low-pass filter FIR 1 being a cubic interpolation filter having a filter coefficient hi (n), a step (2) of inputting the image signal Xij to at least one of the second interpolation low-pass filters FIR 2 each being an interpolation filter having a filter coefficient hi' (n) and a lower cutoff frequency than the FIR 1, a step (3) of setting the FIR 1 into an outputting state to obtain an image signal through a band-pass filter, step (4) of setting the FIR 2 into an outputting state to obtain an image signal tij' through a cutoff filter, a step (5) of inputting the image signals tij, tij' to a subtractor to obtain a different signal tij-tij', and a step (6) of obtaining an output of an image or figure signal Yij using an equation Yij=tij+S(tij-tij') where S is a sharpness level control coefficient.