• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.231-234
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• 2016

본 논문에서는 전송하고자 하는 원영상 대신에 전혀 다른 영상을 전송하여 원영상 정보를 보호하는 스테가노그래피(steganography) 기법을 제안한다. 전송할 영상의 자연스러움을 잃어버리지 않으면서 원영상을 복구할 수 있는 차영상 정보를 LSB(Least Significant Bit)에 담고, 픽셀간의 위치 관계를 무작위로 섞어 줌으로써, 원영상을 보호하는 기법을 제안한다. 본 논문에서는 우선 원영상과 전송할 영상 (cover image)의 차영상을 생성하고, 각 픽셀의 차이값을 큰 범위로 양자화하여 차영상의 데이터 크기를 줄인다. 그리고, 각 픽셀의 차이값을 전송할 영상의 4 픽셀에 걸쳐서 하위 2bit 에 나누어 담는다. 8bit 영상에서 하위 2 bit 를 다루기 때문에, 각 채널 밝기값의 최대 차이값은 3 으로 설정되어 자연스럽게 영상을 생성할 수 있다. 끝으로 신호의 보호를 위하여 차영상의 픽셀과 전송할 영상의 픽셀간의 대응위치를 무작위 순열로 변환하여 외부에서 쉽게 복원할 수 없도록 한다. 이러한 스테가노그래피 제안 기법을 통하여 원영상 대신에 커버 영상을 전송함으로써, 자연스러운 정보전송이 가능하며, 외부의 감시와 복원에 안전한 정보보호 기능이 강화될 수 있다. 여러 영상에 대한 실험을 통한 제안 기법에 의하면, 전송되는 커버 영상이 자연스럽기 때문에 외부에서 정보가 숨겨진 사실을 느끼지 못하며, 송수신 장치에 내장된 무작위 순열을 통하여 외부에서는 원영상 정보를 복구하는 것도 매우 어렵게 되어 있음을 확인하였다. 본 제안 기법은 군사통신이나 중요한 정보를 다루는 기관에서의 정보 전달 및 정보보호 시스템에서 사용될 수 있다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.7
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• pp.81-88
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• 2004

In this paper, a low power area efficient charge recycling predecoder (AE-CRPD) is proposed. The AE-CRPD is modified from the conventional charge recycling predecoder (CNV-CRPD). The AE-CRPD significantly reduces the area and power of the control circuits for the charge recycling operation. It saves 38% area and 8% power of the 2-to-4 CNV-CRPD. It also utilizes the property of the consecutive address increase in the memory. The AE-CRPDs are used for the frequently transited least significant bits and the conventional predecoders are used for the occasionally transited most significant bits. It saves 23% power of the 12-bit conventional predecoder.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2C
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• pp.181-188
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• 2007

This paper proposed a watermark embedding/extracting method using CABAC(Context-based Adaptive Binary Arithmetic Coding) which is the entropy encoder for the main profile of MPEG-4 Part 10 H.264/AVC. This algorithm selects the blocks and the coefficients in a block on the bases of the contexts extracted from the relationship to the adjacent blocks and coefficients. A watermark bit is embedded without any modification of coefficient or with replacing the LSB(Least Significant Bit) of the coefficient with a watermark bit by considering both the absolute value of the selected coefficient and the watermark bit. Therefore, it makes it hard for an attacker to find out the watermarked locations. By selecting a few coefficients near the DC coefficient according to the contexts, this algorithm satisfies the robustness requirement. From the results from experiments with various kinds and various strengths of attacks the maximum error ratio of the extracted watermark was 5.02% in maximum, which makes certain that the proposed algorithm has very high level of robustness. Because it embeds the watermark during the context modeling and binarization process of CABAC, the additional amount of calculation for locating and selecting the coefficients to embed watermark is very small. Consequently, it is highly expected that it is very useful in the application area that the video must be compressed right after acquisition.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.73-76
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• 2001

In this paper, we utilize a HVS(Human Visual System) watermarking method where watermarks are embedded in a DFT domain. The HVS watermarking method is robust for attacks like JPEC, filtering, noise, etc. But, when images are attacked by basic geometric attacks as cropping, scaling, rotation, a watermarks may not be detected. In this paper, we introduce the HVS watermarking method that inserts references In a domain of LSB(Least Significant Bit) of image. Experimental results show that the proposed method based on HVS watermarking method gives more robustness to the basic geometric attacks compared with original HVS watermarking methods.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1427-1430
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• 2003

본 논문에서는 저작권 보호를 위하여 임계값을 이용한 워터마킹 기법을 제안한다 저작권을 보호하기 위하여 원 영상을 웨이블릿 변환하여 얻어진 웨이블렛 계수의 LSB(least significant bit)와 워터마크 영상을 동적 임계값을 적용하여 생성한 4장의 이진영상을 각 주파수 영역 HL1, LH1, HL2, LH2에서 XOR연산을 하여 워터마크를 삽입한다. 화질 열화가 많은 저주파 영역과 손실압축에 약한 고주파 영역을 제외한 영역에 워터마크를 삽입하였다. 실험결과로써, 화질의 열화가 적은 워터마크 삽입영상을 얻을 수 있었으며, 강인하게 워터마크가 추출이 되었다.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.697-700
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• 2000

워터마크의 실현방법은 크게 두 가지로 나누어지는데, 하나는 공간영역에서 처리방법이고 다른 하나는 주파수영역에서 처리방법이다. 초기에는 공간영역에서 처리가 많이 연구되었으나 공간영역에서의 워터마크 삽입방법은 주로 least significant bit(LSB)을 조작하기 때문에 주파수영역의 방법보다 각종 신호처리에 의해 워터마크가 쉽게 없어지는 단점이 생긴다. 따라서 현재는 그런 단점들을 잘 극복할 수 있는 방법으로 주파수 영역에서의 워터마크 삽입 방법이 많이 쓰인다. 본 논문에서는 디지털 영상을 위한 다해상도 이산 웨이브렛 변환을 사용한 워터마킹 방법을 제안하였다.

• ETRI Journal
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• v.35 no.3
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• pp.512-522
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• 2013

In this paper, the radius weight mean (RWM) and the feature-embedding technique are used to present a novel watermarking scheme for color images. Simulations validate that the stego-images generated by the proposed scheme are robust against most common image-processing operations, such as compression, color quantization, bit truncation, noise addition, cropping, blurring, mosaicking, zigzagging, inversion, (edge) sharpening, and so on. The proposed method possesses outstanding performance in resisting high compression ratio attacks: JPEG2000 and JPEG. Further, to provide extra hiding storage, a steganographic method using the RWM with the least significant bit substitution technique is suggested. Experiment results indicate that the resulting perceived quality is desirable, whereas the peak signal-to-noise ratio is high. The payload generated using the proposed method is also superior to that generated by existing approaches.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.1
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• pp.25-32
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• 2014

In this paper, we proposed a partial-way set associative cache memory with an effective memory access time and low energy consumption. In the proposed set-associative cache memory, it is allowed to access only a 2-ways among 4-way at a time. Choosing ways to be accessed is made dynamically via the least significant two bits of the tag. The chosen 2 ways are sequentially accessed by the way selection bits that indicate the most recently referred way. Therefore, each entry in the way has an additional bit, that is, the way selection bit. In addition, instead of the 4-way LRU or FIFO algorithm, we can utilize a simple 2-way replacement policy. Simulation results show that the energy*delay product can be reduced by about 78%, 14%, 39%, and 15% compared with a 4-way set associative cache, a sequential-way cache, a way-tracking cache, and a way cache respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.3
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• pp.600-612
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• 2013

In 2006, Zhang and Wang proposed a data hiding scheme based on Exploiting Modification Direction (EMD) to increase data hiding capacity. The major benefit of EMD is providing embedding capacity greater than 1 bit per pixel. Since then, many EMD-type data hiding schemes have been proposed. However, a serious disadvantage common to these approaches is that the embedded data is compromised when the embedding function is disclosed. Our proposed secure data hiding scheme remedies this disclosure shortcoming by employing an additional modulus function. The provided security analysis of our scheme demonstrates that attackers cannot get the secret information from the stegoimage even if the embedding function is made public. Furthermore, our proposed scheme also gives a simple solution to the overflow/underflow problem and maintains high embedding capacity and good stegoimage quality.

• Journal of Information Processing Systems
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• v.9 no.3
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• pp.405-424
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• 2013

This research paper proposes a secured, robust approach of information security using steganography. It presents two component based LSB (Least Significant Bit) steganography methods for embedding secret data in the least significant bits of blue components and partial green components of random pixel locations in the edges of images. An adaptive LSB based steganography is proposed for embedding data based on the data available in MSB's (Most Significant Bits) of red, green, and blue components of randomly selected pixels across smooth areas. A hybrid feature detection filter is also proposed that performs better to predict edge areas even in noisy conditions. AES (Advanced Encryption Standard) and random pixel embedding is incorporated to provide two-tier security. The experimental results of the proposed approach are better in terms of PSNR and capacity. The comparison analysis of output results with other existing techniques is giving the proposed approach an edge over others. It has been thoroughly tested for various steganalysis attacks like visual analysis, histogram analysis, chi-square, and RS analysis and could sustain all these attacks very well.