• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.83-88
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• 2013

Recently, by increasing the number of smartphone users, the applications for product brochure and advertising service using a technology of augmented reality are also taking place exponentially. The term, augmented reality, is an application of providing composite view with real world and virtual world, and synthesizing the information to make it look-like things that exist in the actual environments of the original real world. In this paper, we present the trends of core technologies and the standardization related on augmented reality in the mobile environment, and discuss the necessary of standards related to image-based augmented reality.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4567-4587
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• 2017

With the growth of the Internet and the extensive applications of image editing software, it has become easier to manipulate digital images without leaving obvious traces. Copy-move is one of the most common techniques for image forgery. Image blind forensics is an effective technique for detecting tampered images. This paper proposes an improved copy-move forgery detection method based on the discrete cosine transform (DCT). The quantized DCT coefficients, which are feature representations of image blocks, are truncated using a truncation factor to reduce the feature dimensions. A method for judging whether two image blocks are similar is proposed to improve the accuracy of similarity judgments. The main transfer vectors whose frequencies exceed a threshold are found to locate the copied and pasted regions in forged images. Several experiments are conducted to test the practicability of the proposed algorithm using images from copy-move databases and to evaluate its robustness against post-processing methods such as additive white Gaussian noise (AWGN), Gaussian blurring, and JPEG compression. The results of experiments show that the proposed scheme effectively detects both copied region and pasted region of forged images and that it is robust to the post-processing methods mentioned above.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.738-741
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• 2009

본 논문에서는 RAW 이미지 포맷 중 PEF, MRW에 대한 분석 결과와 RAWImage Viewer에 대해 소개한다. DSLR 디지털 카메라로 촬영되는 이미지 파일은 범용의 JPEG 포맷이나 제조사별 독자적인 RAW 이미지 포맷으로 저장된다. 이러한 RAW 이미지 파일을 PMP 등의 휴대용 멀티미디어 기기나 디지털액자에서 재생 및 확인하기 위한 요구가 증대되고 있다. 하지만, RAW 이미지 포맷이 디지털 카메라 제조사별로 다르고, 해당 포맷에 대한 구체적인 정보가 공개되지 않아 대부분의 휴대용 멀티미디어 기기에서 RAW 이미지 파일 재생 기능을 완벽하게 지원하지 못하고 있다. 본 논문에서는 RAW 이미지 파일 포맷을 분석하여 다양한 임베디드 멀티미디어 기기에서 모든 RAW 이미지 파일을 지원할 수 있는 라이브러리 구축을 위한 연구 결과 중 일부를 소개한다. Cannon의 CRW, CR2 포맷과 Nikon의 NEF 분석 결과에 이어 PEF, MRW에 대한 분석 결과와 RAW 이미지 출력 및 분석 기능이 포함된 RAWImage Viewer에 대해 설명한다. 연구 결과는 RAW 파일을 재생할 수 있는 임베디드 장비 및 PC용 RAW 이미지 파일 재생 라이브러리를 구축 및 응용 프로그램 개발시 활용될 것이다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.289-295
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• 2006

The Musical Slide Show MAF, which currently being standardized by MPEG, conveys the concept of combining several established standard technologies in a single file format. It defines the format of packing up MP3 audio data, along with MPEG-7 Simple Metadata Profile and MPEG-21 Digital Item Declaration metadata; with JPEC images and optional text, and synchronizes them all together to create a slideshow of JPEC image data associated to MP3 audio data during the audio playback. The implementation of Musical Slide Show MAF can be a music karaoke file where users can sing along while listening to the music, view the JPEG slideshow and reading the lyrics; or a story-telling file where users can listen to the narrated story by looking at the related illustration slideshow of the story In this paper we present the tool to producing the Musical Slide Show MAF contents. Regardless the knowledge of user on the MAF file format, the authoring tool simplify the manner of packaging several multimedia contents into single file.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3911-3925
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• 2018

This paper proposes a novel steganography method to hide secret data during the generation of tangle patterns. Different from the traditional steganography based on modifying natural images, we propose to construct stego images according to the secret messages. We first create a model to group a selected image contour, and define some basic operations to generate various pattern cells. During data hiding, we create a cell library to establish the relationships between cells and secret data. By painting the cell inside the image contour, we create a dense tangle pattern to carry secret data. With the proposed method, a recipient can extract the secret data correctly. Experimental results show that the proposed method has a flexible embedding capacity. The constructed stego tangle image has good visual effects, and is secure against adversaries. Meanwhile, the stego tangle pattern is also robust to JPEG compression.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1860-1868
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• 1998

A simple postprocessing algorithm is proposed to reduce the blocky artifacts of Block Discrete Cosine Transform (BDCT) coded images. Since the block noise is mostly antisymmetric relative to the block boundaries, we model the blocky noise as one-dimensional antisymmertric functions made by superposing DCT basis functions. observing the frequency characteristics of the noies model, we approximate its high frequency components as those of step functions. Then the proposed postprocessing algorithm eliminates the carefully selected high frequency components of step functions in the one-dimensional sN-point DCT domain, when the encoding block size is $N\;{\times}\;N$. It is shown that the proposed algorithm can also be performed in the spatial domain without computational burden of transforms. The experimental results show that the proposed algorithm well reduces the blocky artifacts in both subjective and objectie viewpoints.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.349-356
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• 1997

In this paper, we propose the lossless coding: scheme for progressive transmission of medical images. The input image is decomposed by the proposed fast adaptive subband decomposition method which is suited for a lossless coding. The decomposed images are coded by an arithmetic coder with two conditioning pixels, and the conditioning pixels are selected differently according to the property of the subbands. The conditioning contexts are usually quantized to reduce the conditional state, and the optimization method of quantization is proposed For the purpose of improving compression ratio in this paper. The proposed lossless coding scheme provides the asymmetric structure of cosec and results in better compression ability than the JPEC lossless coding[ 1 ].

• Journal of Ubiquitous Convergence Technology
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• v.2 no.1
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• pp.18-26
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• 2008

The invariance relation existing in the non-negative matrix factorization (NMF) is used for constructing robust image hashes in this work. The image is first re-scaled to a fixed size. Low-pass filtering is performed on the luminance component of the re-sized image to produce a normalized matrix. Entries in the normalized matrix are pseudo-randomly re-arranged under the control of a secret key to generate a secondary image. Non-negative matrix factorization is then performed on the secondary image. As the relation between most pairs of adjacent entries in the NMF's coefficient matrix is basically invariant to ordinary image processing, a coarse quantization scheme is devised to compress the extracted features contained in the coefficient matrix. The obtained binary elements are used to form the image hash after being scrambled based on another key. Similarity between hashes is measured by the Hamming distance. Experimental results show that the proposed scheme is robust against perceptually acceptable modifications to the image such as Gaussian filtering, moderate noise contamination, JPEG compression, re-scaling, and watermark embedding. Hashes of different images have very low collision probability. Tampering to local image areas can be detected by comparing the Hamming distance with a predetermined threshold, indicating the usefulness of the technique in digital forensics.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.3
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• pp.124-130
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• 2006

A wavelet-based image compression system allowing both lossless and lossy image compression is proposed in this paper. The proposed algorithm consists of the two stages. The first stage uses the wavelet packet transform and the quad-tree coding scheme for the lossy compression. In the second stage, the residue image taken between the original image and the lossy reconstruction image is coded for the lossless image compression by using the integer wavelet transform and the context based predictive technique with feedback error. The proposed wavelet-based algorithm, allowing an optional lossless reconstruction of a given image, transmits progressively image materials and chooses an appropriate wavelet filter in each stage. The lossy compression result of the proposed algorithm improves up to the maximum 1 dB PSNR performance of the high frequency image, compared to that of JPEG-2000 algorithm and that of S+P algorithm. In addition, the lossless compression result of the proposed algorithm improves up to the maximum 0.39 compression rates of the high frequency image, compared to that of the existing algorithm.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3236-3237
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• 2000

본 논문에서는 의료 영상분야에서 많이 활용되고 있는 기존의 영상 획득,저장 및 전송 시스템(PACS)에 스테레오 내시경 영상이 추가될 수 있도록 기존의 PACS에 스테레오 기능의 관찰(viewing) 시스템을 추가하였으며 기본 기능으로 1) 3차원 스테레오 좌,우 독립 영상의 선택과 합성 2) 기존의 합성된 스테레오 영상의 선택이 가능하도록 하였으며 3) 스테레오 영상의 Dicom 표준이 없는 상황을 고려하여 기본적인 카메라 관련 사항(카메라 사양, 초점 거리, 베이스라인 등)을 입력할 수 있는 기록 필드를 삽입하였다. 또한 임상적으로 수용 가능한 3차원 스테레오 영상의 PACS내 효율적 저장법을 제시하기 위하여 의료 영상에 많이 활용되는 JPEG과 Wavelet 압축법을 각각 이용하여 3차원 좌,우 독립영상과 복합 영상의 효율적 압축비를 PSNR을 중심으로 비교하였다.