Invention Grant
- Patent Title: Arbitrary ratio image resizing in the DCT domain
- Patent Title (中): DCT域中的任意比例图像调整大小
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Application No.: US13535945Application Date: 2012-06-28
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Publication No.: US08478059B2Publication Date: 2013-07-02
- Inventor: Longji Wang , En-hui Yang
- Applicant: Longji Wang , En-hui Yang
- Applicant Address: CA Waterloo, Ontario
- Assignee: Research In Motion Limited
- Current Assignee: Research In Motion Limited
- Current Assignee Address: CA Waterloo, Ontario
- Agency: Rowand LLP
- Main IPC: G06K9/36
- IPC: G06K9/36 ; G06K9/46 ; G06K9/32

Abstract:
To resize a compressed image, first and second scaling parameters P and Q are determined in accordance with the block numbers L and M and the scaling ratio L/M or M/L. A non-uniform, or uneven, sampling in the DCT domain is then applied to coefficients of successive blocks in the compressed image in accordance with the scaling parameters. In an embodiment, P blocks are sampled and transformed from a given block length to |P| according to a |P|-point IDCT, while Q blocks are sampled and transformed from a given block length to |Q| according to a |Q|-point IDCT. The non-uniformly sampled and transformed pixel domain samples are then regrouped into a predetermined block size and transformed back to generate the DCT coefficient of the compressed image. The proposed method significantly reduces the computational complexity compared with other DCT domain arbitrary ratio image resizing approach.
Public/Granted literature
- US20120263392A1 ARBITRARY RATIO IMAGE RESIZING IN THE DCT DOMAIN Public/Granted day:2012-10-18
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