• ETRI Journal
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• 제34권3호
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• pp.429-438
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• 2012

This study presents two reversible data hiding schemes based on the coefficient shifting (CS) algorithm. The first scheme uses the CS algorithm with a mean predictor in the spatial domain to provide a large payload while minimizing distortion. To guard against manipulations, the second scheme uses a robust version of the CS algorithm with feature embedding implemented in the integer wavelet transform domain. Simulations demonstrate that both the payload and peak signal-to-noise ratio generated by the CS algorithm with a mean predictor are better than those generated by existing techniques. In addition, the marked images generated by the variant of the CS algorithm are robust to various manipulations created by JPEG2000 compression, JPEG compression, noise additions, (edge) sharpening, low-pass filtering, bit truncation, brightness, contrast, (color) quantization, winding, zigzag and poster edge distortion, and inversion.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.857-860
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• 2000

This paper presents a new watermarking method based on wavelet transform. Embedding algorithm call define robust area by varying thresholds and gives a watermark image the priority of significance by analyzing spatial correlation of the watermark image. Detector can adjust thresholds to the distorted watermarked image. Also detector can extract the embedded data without an original image. A new measurement for detecting the correct watermark is suggested. Simulation results show that the embedded watermark is robust against various signal processing and compression attacks.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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• pp.290-294
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• 2008

Conversion of the building can be a core strategy to activate the urban regeneration. Especially in the decayed district, the conversion or retrofit of old building can be a core catalyst to stimulate the urban regeneration. Throughout the case study, a conversion from office to dwelling, there were figured out the design strategies to respond to spatial, functional requirements. The results are as follows ; 1) The main design strategy is to articulate the space by embedding the wall, mass in the rectangular space. 2) to respond to the small size of space, the flexible, movable wall system Is adopted. This gives the selectiveness to the use of space. 3) to secure the livability of interior space, the buffer zone, a terrace space, is fully utilized. This space acts as thermal buffer zone as well as a semi-interior space.

• 방송공학회논문지
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• 제6권3호
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• pp.270-282
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• 2001

이 논문은 현재 잘 알려진 3종류의 블라인드 워터마크 삽입 및 검출방법을 신호처리 관점에서 소개한다. 이들 3가지는 각각 상 관관계기반 방법, 에코기반 방법, 그리고 패치워크 방법이다. 이들 방법은 시간영역 (또는 공간영역) 또는 변환영역에서 적용할 수 있다. 이 논문에서는 이들 세 방법을 구현하는데 필요한 기초이론 및 구현방법을 제공한다. 아울러 실제 약간의 실험 결과들을 포함시켰다.

• Journal of Information Processing Systems
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• 제15권2호
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• pp.261-270
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• 2019

In order to protect secret digital documents against vulnerabilities while communicating, steganography algorithms are applied. It protects a digital file from unauthorized access by hiding the entire content. Pixel-value-difference being a method from spatial domain steganography utilizes the difference gap between neighbor pixels to fulfill the same. The proposed approach is a block-wise embedding process where blocks of variable size are chosen from the cover image, therefore, a stream of secret digital contents is hidden. Least significant bit (LSB) substitution method is applied as an adaptive mechanism and optimal pixel adjustment process (OPAP) is used to minimize the error rate. The proposed application succeeds to maintain good hiding capacity and better signal-to-noise ratio when compared against other existing methods. Any means of digital communication specially e-Governance applications could be highly benefited from this approach.

• Journal of Information Processing Systems
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• 제15권1호
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• pp.169-180
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• 2019

Transmitting visual information over a broadcasting network is not only prone to a copyright violation but also is a forgery. Authenticating such information and protecting its authorship rights call for more advanced data encoding. To this end, electronic watermarking is often adopted to embed inscriptive signature in imaging data. Most existing watermarking methods while focusing on robustness against degradation remain lacking of measurement against security loophole in which the encrypting scheme once discovered may be recreated by an unauthorized party. This could reveal the underlying signature which may potentially be replaced or forged. This paper therefore proposes a novel digital watermarking scheme in temporal-frequency domain. Unlike other typical wavelet based watermarking, the proposed scheme employed the Lorenz chaotic map to specify embedding positions. Effectively making this is not only a formidable method to decrypt but also a stronger will against deterministic attacks. Simulation report herein highlights its strength to withstand spatial and frequent adulterations, e.g., lossy compression, filtering, zooming and noise.

• Journal of Information Processing Systems
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• 제19권1호
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• pp.80-88
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• 2023

RGB-thermal (RGB-T) tracking using unmanned aerial vehicles (UAVs) involves challenges with regards to the similarity of objects, occlusion, fast motion, and motion blur, among other issues. In this study, we propose dynamic tracking aggregation (DTA) as a unified framework to perform object detection and data association. The proposed approach obtains fused features based a transformer model and an L1-norm strategy. To link the current frame with recent information, a dynamically updated embedding called dynamic tracking identification (DTID) is used to model the iterative tracking process. For object association, we designed a long short-term tracking aggregation module for dynamic feature propagation to match spatial and temporal embeddings. DTA achieved a highly competitive performance in an experimental evaluation on public benchmark datasets.

• 한국정보과학회논문지:소프트웨어및응용
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• 제37권6호
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• pp.417-429
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• 2010

가역 워터마킹 기법은 디지털 콘텐츠에 지각적 투명성을 유지하며 워터마크를 삽입한 후에, 이를 아무런 손상 없이 원본 상태로 복원할 수 있는 메시지 은닉 수단이다. 영상의 품질이 매우 중요한 의학, 군사, 원격측량, 예술작품 분야에서 워터마킹 응용은 영상처리와 분석과정에서 손상 없는 원본이 필요하기 때문에, 메시지를 검출하고 원본으로 복원하는 과정에서 어떠한 손상이라도 허용될 수 없는 완전한 가역성이 보장되어야 한다. 본 논문에서는 영상의 인접한 픽셀들 간의 차이값 히스토그램을 수정하여 메시지를 은닉하는 가역 영상 워터마킹 알고리즘을 제안한다. 제안한 방법에서는 높은 삽입용량과 지각적 투명성을 만족하기 위해 영상의 인접 픽셀들 간의 높은 유사성 특징을 이용하였다. 또한 오류 예측 보정 기법을 통하여 워터마크 삽입과정에서 발생할 수 있는 오버/언더플로우 문제와 salt-and-pepper 잡음 현상을 방지하였다. 제안한 가역 워터마킹 알고리즘의 성능을 검증하기 위하여 다양한 영상들에 대하여 기존 알고리즘들과 비교 분석하였다. 실험 결과에 따르면 제안한 알고리즘은 완전한 가역성과 함께 낮은 왜곡을 유지하면서도 높은 삽입용량을 얻을 수 있었다.

• 대한전자공학회논문지SP
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• 제40권6호
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• pp.51-60
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• 2003

워터마킹(Watermarking) 기법은 멀티미디어 컨텐츠의 저작권 보호를 위해서 특정 데이터를 저작물의 품질이나 데이터 크기의 변화 없이 삽입하고, 필요시 이를 검출하는 기술이다. 워터마크가 삽입된 컨텐츠는 사람의 육안이나 청각으로 구별할 수 없어야 하고 여러 종류의 변환 또는 고의적 공격에 강인성을 가져야한다. 본 논문에서는 영상의 공간 영역과 주파수 영역에 대한 정보를 함께 갖는 웨이블릿(Wavelet) 변환영역에서 워터마킹을 수행하는 방법을 제안하였다. 제안한 방법에서는 강인성과 비가시성을 동시에 만족하기 위해 다중 임계값을 사용하였다. 워터마크 삽입 위치는 상관도가 높은 부대역 계수들의 유사성을 조사하고 관련 주파수 대역에서 계수의 중요도를 검증한 뒤 워터마크를 삽입할 위치로 결정하였다. 이 때 유사성의 표현은 부대역간의 계수 값 차를 이용하였고, 이 차들의 분포는 워터마크를 삽입하고 검출하는데 사용한다. 워터마크의 검출은 부대역간의 특성을 이용함으로써 원래의 영상을 사용하지 않고 검출할 수 있다. 이러한 특성들 때문에 제안한 워터마킹 알고리즘은 JPEG 압축 공격 등을 비롯한 일반적인 영상처리에 대해 비가시성과 강인성을 동시에 만족함을 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4568-4587
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• 2014

Authentication of videos and images based on the content is becoming an important problem in information security. Unfortunately, previous studies lack the consideration of Kerckhoffs's principle in order to achieve this (i.e., a cryptosystem should be secure even if everything about the system, except the key, is public knowledge). In this paper, a solution to the problem of finding a relationship between a frame's index and its content is proposed based on the creative utilization of a robust manifold feature. The proposed solution is based on a novel semi-fragile watermarking scheme for H.264/AVC video content authentication. At first, the input I-frame is partitioned for feature extraction and watermark embedding. This is followed by the temporal feature extraction using the Isometric Mapping algorithm. The frame index is included in the feature to produce the temporal watermark. In order to improve security, the spatial watermark will be encrypted together with the temporal watermark. Finally, the resultant watermark is embedded into the Discrete Cosine Transform coefficients in the diagonal positions. At the receiver side, after watermark extraction and decryption, temporal tampering is detected through a mismatch between the frame index extracted from the temporal watermark and the observed frame index. Next, the feature is regenerate through temporal feature regeneration, and compared with the extracted feature. It is judged through the comparison whether the extracted temporal watermark is similar to that of the original watermarked video. Additionally, for spatial authentication, the tampered areas are located via the comparison between extracted and regenerated spatial features. Experimental results show that the proposed method is sensitive to intentional malicious attacks and modifications, whereas it is robust to legitimate manipulations, such as certain level of lossy compression, channel noise, Gaussian filtering and brightness adjustment. Through a comparison between the extracted frame index and the current frame index, the temporal tempering is identified. With the proposed scheme, a solution to the Kerckhoffs's principle problem is specified.