Patent Number: 6,298,166

Title: Image transformations in the compressed domain

Abstract: Image processing techniques which involve direct manipulation of the compressed domain representation of an image to achieve the desired spatial domain processing without having to go through a complete decompression and compression process. The techniques include processing approaches for performing the eight operations in D.sub.4 (the dihedral group of symmetries of a square) on JPEG images using the discrete cosine transform (DCT) domain representation of the images directly. For a task such as image rotation by 90.degree. (an operation in D.sub.4), DCT-domain based methods can yield nearly a five-fold increase in speed over a spatial-domain based technique. These simple compressed-domain based processing techniques are well suited to the imaging tasks that are needed in a JPEG-based digital still-camera system.

Inventors: Ratnakar; Viresh (Sunnyvale, CA), Ivashin; Victor (Danville, CA), Bhaskaran; Vasudev (Mountain View, CA)

Assignee: Seiko Epson Corporation

International Classification: G06T 3/60 (20060101); G06T 9/00 (20060101); G06T 3/00 (20060101); H04N 7/26 (20060101); G06K 009/36 ()

Expiration Date: 10/02/2018