Method and apparatus for resizing images using the discrete trigonometric transform

摘要

A method and apparatus using the discrete cosine transform (DCT) to resize an image. To reduce an image, the method and apparatus exploits the convolution-multiplication property of the DCT to implement the anti-aliasing filter in the DCT domain, then the filtered coefficients are operated on to produce DCT coefficients of the reduced-size image. To increase an image, the DCT coefficients of the original image are operated on to produce coefficients of the larger image, then the convolution-multiplication property of the DCT is used to implement an anti-imaging filter. These DCT operations can be applied to the image as a whole or can be applied to non-overlapping blocks of the image.