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An Improved DC Recovery Method from AC Coefficients of DCT-Transformed Images

Shujun Li1, Junaid Jameel Ahmad1, Dietmar Saupe1 and C.-C. Jay Kuo2

1 University of Konstanz, Germany
2 University of Southern California, USA

In Proceedings of 17th IEEE International Conference on Image Processing (ICIP 2010, Hong Kong, China, September 26-29, 2010), pp. 2085-2088, IEEE.

Copyright 2010 IEEE. Published in Proceedings of 2010 17th IEEE International Conference on Image Processing (ICIP 2010, Hong Kong, China, September 26-29, 2010), pp. 2085-2088, 2010, DOI: 10.1109/ICIP.2010.5653467. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works, must be obtained from the IEEE. Contact: Manager, Copyrights and Permissions / IEEE Service Center / 445 Hoes Lane / P.O. Box 1331 / Piscataway, NJ 08855-1331, USA. Telephone: + Intl. 908-562-3966.

ATTENTION: We have found an even better method that significantly outperforms this one and can also handle the case when more than one DCT coefficient is missing. A paper about the new method has been accepted to ICIP2011. Click here to see more details.

Abstract

Motivated by the work of Uehara et al. [1], an improved method to recover DC coefficients from AC coefficients of DCT-transformed images is investigated in this work, which finds applications in cryptanalysis of selective multimedia encryption. The proposed under/over-flow rate minimization (FRM) method employs an optimization process to get a statistically more accurate estimation of unknown DC coefficients, thus achieving a better recovery performance. It was shown by experimental results based on 200 test images that the proposed DC recovery method significantly improves the quality of most recovered images in terms of the PSNR values and several state-of-the-art objective image quality assessment (IQA) metrics such as SSIM and MS-SSIM.

Links

External links

USO Method vs. Our Proposed FRM Method

Two Properties

USO Method

FRM Method

Performance Comparison

Original Image emotion icon DC-Encrypted Image

HK_shop (Original) emotion icon HK_shop (Encrypted)

Simple DC Recovery Method

This method simply sets the DC coefficient of each block to be the midpoint of the valid range.

HK_shop (DC-free)

USO Method

HK_shop (USO Scan 1) + HK_shop (USO Scan 2) + HK_shop (USO Scan 3) + HK_shop (USO Scan 4) emotion icon HK_shop (USO)

Our FRM Method

HK_shop (FRM Scan 1) + HK_shop (FRM Scan 2) + HK_shop (FRM Scan 3) + HK_shop (FRM Scan 4) emotion icon HK_shop (FRM)

Performance Comparison: Yet Another Example

Original Image emotion icon DC-Encrypted Image

birds (Original) emotion icon birds (Encrypted)

Simple DC Recovery Method

birds (DC-free)

USO Method

birds (USO Scan 1) + birds (USO Scan 2) + birds (USO Scan 3) + birds (USO Scan 4) emotion icon birds (USO)

Our FRM Method

birds (FRM Scan 1) + birds (FRM Scan 2) + birds (FRM Scan 3) + birds (FRM Scan 4) emotion icon birds (FRM)

USO vs. FRM (200 Test Images)

FRM vs. USO (10 IQA metrics)

Figure 6: The performance improvement of the proposed FRM method over the USO method using different IQA metrics. Note that the range of some metrics (SSIM, MS-SSIM, VIF, VIFP, UIQ) is [0,1], so the mean values corresponding to these metrics are relatively small.

A vector graphics edition of Figure 6 (which can be enlarged to see more detail) is available for downloading at http://hooklee.com/Papers/Data/AC2DC/FRM_vs_USO_IQAs.pdf.

Acknowledgments

Shujun Li and Junaid Jameel Ahmad were supported by the Zukunftskolleg of the University of Konstanz, which is part of the "Excellence Initiative" Program of the DFG (German Research Foundation).

References

[1]  Takeyuki Uehara, Reihaneh Safavi-Naini, and Philip Ogunbona, "Recovering DC coef´Čücients in block-based DCT," IEEE Transactions on Image Processing, vol. 15, no. 11, pp. 3592-3596, IEEE, 2006

Only one revision exists, which was created (or modified) by hooklee at Sunday, June 19, 2016 9:10:14 PM.
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