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1
Content available remote An Edge-based Image Copy Detection Scheme
100%
Lin C.-C. , Wang S.-S.
Fundamenta Informaticae
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2008
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tom Vol. 83, nr 3
299-318
EN
This paper presents a novel scheme to detect copied versions of digital images, particularly in an Internet environment based on edge information of images. The edge information is used to generate the signature set for a corresponding image. The edge-based signature sets are then used to compute the distortions between query images and test images, from among which a user wants to find copies. Experimental results confirm that the proposed scheme not only withstands various modifications of an original image but also offers good detection performance in dealing with various rotations, shifting of 17.5% of the width or height of an image, and cutting out up to 45% of the area of an image, which previous research work has found difficult to detect. Therefore, our proposed scheme could be very helpful in detecting copies of digital images transmitted in an Internet environment.
2
Content available remote Adaptive Data Embedding Scheme Based on Similar and Dissimilar Clustering Strategies
80%
Chang C.-C. , Lin C.-C. , Chen Y.-C.
Fundamenta Informaticae
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2008
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tom Vol. 88, nr 1-2
23-45
EN
Embedding large amounts of secret data into a cover image with low distortion is an important research issue in steganography. The proposed scheme uses two clustering technologies - similar and dissimilar clustering - to enhance hiding capacity as provided by Du and Hsu’s scheme. In general, the hiding capacity of our proposed scheme is higher than that of Du and Hsu’s scheme, about 16 Kb for the same image quality. In addition, the image quality of our proposed scheme is more than provided by the schemes of either Du and Hsu’s or Shie et al., about 2 dB. Moreover, the distortion for each test image in our proposed scheme is always less than those caused by Du and Hsu’s and Shie et al.’s schemes. Experimental results confirm that the proposed scheme is significantly better than earlier works.
3
Content available remote Reversible Data Hiding Based on Three-Circular-Pixel Difference Expansion
80%
Lin C.-C. , Yang S.-P. , Hsueh N.-L.
Fundamenta Informaticae
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2009
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tom Vol. 91, nr 3-4
581-595
EN
This paper proposes a reversible data hiding scheme based on three-circular-pixel (TCP) difference expansion. To embed a message in an image, the image is divided into three-pixel blocks, each of which is, then, transformed into a TCP block with two differences. When the pixel value of the largest pixel in the TCP block is increased, two differences are increased—one is between the largest and the smallest, and the other is between the largest and the middle. Expanding the two differences in the block by increasing the largest pixel value may make the image less modified. In addition, the number of pixel pairs is increased to two thirds of the number of pixels in the image. Compared to Tian's study, both the visual quality and the embedding capacity of the image are significantly improved.
4
Content available remote Block Prediction Vector Quantization for Grayscale Image Compression
80%
Hu Y.-C. , Lin C.-C. , Chi K.-L.
Fundamenta Informaticae
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2007
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tom Vol. 78, nr 2
257-270
EN
This paper presents a new image compression scheme based on vector quantization (VQ) that exploits the inter-block and intra-block correlations in grayscale images. The similar block prediction technique is designed to encode the image blocks by their similar neighboring encoded blocks. Besides, two codebooks are used in the proposed scheme to exploit the intra-block correlation within each image block. Experimental results show that the proposed scheme not only provides good image qualities but also cuts down the required bit rates.
5
Content available remote A Novel Image Hiding Scheme Based on VQ and Hamming Distance
80%
Chang C.-C. , Tai W.-L. , Lin C.-C.
Fundamenta Informaticae
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2007
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tom Vol. 77, nr 3
217-228
EN
Data hiding is popularly employed in protecting the copyright, secret information and communication secretly with the convenience of network communication. In order to reduce the amount the transmitted data via network, VQ (vector quantization) is applied to compressing the transmitted data. Since VQ is a low-bit-rate compression scheme, it is difficult to find large redundant hiding space and to get stego-images with high quality for hiding data in VQ-based compressed images. A hiding method for VQ-based compressed images is proposed in this paper according to the Hamming distance between the index values of codewords. Our method makes hiding data more effective and provides stego-images with higher quality than other conventional methods. Experimental results demonstrate the effectiveness and the feasibility of our method.
6
Content available remote High-Performance Reversible Data Hiding
80%
Lin C.-C. , Hsueh N.-L. , Shen W.-H.
Fundamenta Informaticae
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2008
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tom Vol. 82, nr 1-2
155-169
EN
This paper proposes a high-performance reversible data hiding algorithm based on the block difference histogram of a cover image. If a message is to be embedded into an image, the difference of the block at the maximum point is increased by 1 or left unchanged if the message bit is 1" or 0", respectively. Experimental results show that the average payload capacity of the test images can be up to 1.52 bits per pixel (bpp). Average payload and pure payload capacities for PSNR ^(3) 30 dB can be up to 1.13 bpp and 1.06 bpp, respectively. Moreover, the original cover image can be recovered without any distortion and the implementation of the proposed algorithm is very easy.
7
Content available remote Adaptively Embedding Binary Data in an Image
80%
Lin C.-C. , Hsueh N.-L. , Shen W.-H.
Fundamenta Informaticae
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2008
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tom Vol. 84, nr 3-4
391-402
EN
In this paper, we propose an embedding algorithm, of high visual quality, that can adaptively embed a binary message into an image. The binary message to be embedded is divided into two segments, each of which is then decomposed into n+1 or n types of sub-messages (where n ^(3) 3 enables each pixel to embed a sub-message), respectively, according to the desired embedding capacity. Embedding is done by leaving the pixel value unchanged or changing it into one of its n or n-1 neighboring values according to the type of the sub-message. From the results of this study, each pixel may not embed a fixed number of message bits and the adjustment of the pixel value is minimal, thus the image quality is significantly improved by adaptively decomposing the message into sub-messages and embedding them into the host image.
8
Content available remote A Robust Content-Based Copy Detection Scheme
80%
Wu M.-N. , Lin C.-C. , Chang C.-C.
Fundamenta Informaticae
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2006
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tom Vol. 71, nr 2,3
351-366
EN
Content-based image copy detection can be used as either an alternative approach or a complementary approach to watermarking. To detect copied versions of digital images, which are generated by various image processes, several schemes have been proposed. However, none of them can successfully detect tampering when those images are rotated 90 or 270 degrees from the original image. To solve this problem, we propose a new copy detection scheme based on Y component of image and block strategy. A test image is just converted to a YUV color model where only Y component is used to generate the image signatures. Then, the transformed image is divided into 8×8 blocks. Finally, the relationship between each block and its neighboring eight blocks are recorded by comparing these block's mean values. This image signature generated by our proposed scheme contains the comparative relationship between each block and its neighboring blocks. Our proposed scheme can detect modifications those are generated by 90 or 270 rotation of original one, which can not be detected by Kim's scheme. The optimal block numbers used for image partition have been explored and the efficiency of the proposed scheme is extensively tested with 20,000 test images.
9
Content available remote A Novel Image Ownership Protection Scheme Based on Rehashing Concept and Vector Quantization
80%
Lin C.-C. , Hu Y.-C. , Chang C.-C.
Fundamenta Informaticae
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2006
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tom Vol. 71, nr 4
443-451
EN
A novel watermarking scheme that is capable of hiding authorization data in a gray-level image is proposed in this letter. The proposed scheme generates a key stream to be the key to connect the authorized image and its watermark. The key stream is extra data rather than data being embedded into the authorized image. Such arrangement can guarantee the integrity of the image. To reduce the complexity in computing the key stream for the authorized gray-level image, two techniques are employed in the proposed scheme. One is the concept of rehashing, and the other is the vector quantization. The benefits of the proposal are to provide a key stream to prove the gray-level's ownership, and to keep the authorized image in its original state without any modification.
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