Image resizing in the compressed domain using subband DCT

Resizing of digital images is needed in various applications, such as transmission of images over communication channels varying widely in their bandwidths, display at different resolutions depending on the resolution of a display device, etc. In this work, we propose a modification of a recently proposed elegant image resizing algorithm by Dugad and Ahuja (2001). We have also extended their approach and our modified versions to color images and studied their performance at different levels of compression for an image. Our proposed modified algorithms, in general, perform better than the earlier method in most cases. Though there is a marginal increase in the computation required in image-halving, the computation overhead of the proposed modification is higher compared to the Dugad-Ahuja algorithm in the case of doubling the images