Browsing by Author "Thien, CC"

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A simple and high-hiding capacity method for hiding digit-by-digit data in images based on modulus function
(2003-12-01)
Thien, CC
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Lin, JC
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資訊工程學系
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Department of Computer Science
This study presents a simple method for high-hiding capacity. The basic concept uses a modulus operation. The proposed method has the following advantages: (1) the proposed method outperforms the simple LSB substitution method given the same range (0-m - 1) of data digits in the embedded data; (2) the proposed method achieves good image vision quality without the need for post-processing; (3) the proposed method is almost as simple as the LSB method in both coding and decoding; (4) the smaller error advantage over the simple LSB substitution method can also be mathematically verified; (5) the error is smaller than [(m - 1)/2] for almost every pixel; (6) the proposed method has high-hiding capacity (for example, the proposed method can hide a 256 x 256 or 256 x 512 image in a 512 x 512 host image). (C) 2003 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved.
An image-sharing method with user-friendly shadow images
(2003-12-01)
Thien, CC
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
This study presents a user-friendly image-sharing method for easier management of the shadow images. The sharing of images among several branches (distributed disks) using the proposed method has several characteristics: 1) fast transmission among branches; 2) fault tolerance; 3) a secure storage system; 4) reduced chance of pirating of high-quality images (as explained in Section V); and 5) most importantly, the provision to each branch manager an easy-to-manage environment (because each shadow image looks like a shrunken version of the original image). The current approach still hits the small-size and channel-independent properties of our previous work,, namely, the size of each shadow image is only 1/r of that of the original image, and any r shadow images can be used for restoration (the restored image is independent of which r shadow images are used).
Secret image sharing
(2002-10-01)
Thien, CC
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
Sharing and hiding secret images with size constraint
(2004-07-01)
Wu, YS
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Thien, CC
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
This paper presents a method for sharing and hiding secret images. The method is modified from the (t, n) threshold scheme. (Comput.Graph. 26(5)(2002)765) The given secret image is shared and n shadow images are thus generated. Each shadow image is hidden in an ordinary image so as not to attract an attacker's attention. Any t of the n hidden shadows can be used to recover the secret image. The size of each stego image (in which a shadow image is hidden) is about 1/t of that of the secret image, avoiding the need for much storage space and transmission time (in the sense that the total size of t stego images is about the size of the secret image). Experimental results indicate that the qualities of both the recovered secret image and the stego images that contain the hidden shadows are acceptable. The photographers who work in enemy areas can use this system to transmit photographs. (C) 2004 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved.