• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2003년도 추계공동학술대회
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• pp.729-732
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• 2003

In this paper, the transformed logo image is used as a watermark image, then the extraction rate is good when the logo image is transformed into randomly distribute Image domain. The robustness is good resist of clipping and noise.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.242-245
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• 2000

In this paper we present new idea to highly compress the images. The previous image is transformed with wavelet and the transformed data are transmitted. The previous image is subtracted from the next image. Then difference values per pixel are scanned to search motion areas and boundaries. In the motion boundaries, motion vectors and error values are transformed with wavelet and transmitted. We also include camera motion estimation and compensation. In this method this system has advantages of more compressive data, better quality of picture and shorter processing time compared to MPEG2, MPEG4.

• 한국통신학회논문지
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• 제16권2호
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• pp.172-179
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• 1991

In this paper we have proposed an efficient coding algorithm using directional filtering. First an image is transformed by using DCT which has better energy compaction and then the transformed image is divided into a low frequency component and several high frequency components. The transformed coefficients of each parts are transmitted respectively by using huffman code and these are transformed inversely at receiver. For the directional components total edge images are reconstructed at zero crossing points. We are able to reduce the amount of data by getting of complex component and making directional angles 90. As a results, this proposed method is better than that of Kunt in respect of processing time and memories. We have 38dB of image quality with objective measurement of PSNR and 0.26bpp of compression ratio which is acceptable.

• 한국콘텐츠학회논문지
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• 제6권7호
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• pp.90-98
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• 2006

디지털 워터마킹은 이미지, 사운드와 같은 멀티미디어 데이터에 지각할 수 없도록 비밀 정보를 삽입하는 기법이다 일반적으로 주파수 영역 워터마킹 기법에서는 원 이미지에 대해 주파수 변환을 하고, 그 변환 면에 부호화된 워터마크 데이터를 삽입한다. 본 논문에서 우리는 Fresnel 변환을 이용한 새로운 컬러 이미지 워터마킹 기법을 제안한다. 워터마크 이미지를 Fresnel 변환시켜 얻은 패턴의 값들을 컬러 이미지에 삽입한다. 본 워터마킹 모델은, 컬러 이미지에 대한 워터마크 삽입을 위해 원 이미지를 RGB 성분에서 YCrCb 성분으로 분해를 한 후 Y 성분에 워터마크 이미지의 Fresnel 변환된 패턴의 실수와 허수 값을 삽입하는 기법이다. 제안된 기법의 유효성을 검증하기 위한 워터마크 삽입 추출 실험 결과 유효성을 입증 할 PSNR 값을 나타냈으며, 또한 JPEG와 같은 손실 압축 공격에 대해 내성을 지니고 있음을 보였다.

• 디지털산업정보학회논문지
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• 제12권2호
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• pp.41-49
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• 2016

Lossless encryption methods are more applicable than lossy encryption methods when marginal distortion is not tolerable. In this research, the author propose a novel lossless symmetric key encryption/decryption technique. In the proposed algorithm, the image is transformed into the frequency domain using the lifting wavelet transform, then the image sub-bands are encrypted in a such way that guarantees a secure, reliable, and an unbreakable form. The encryption involves scattering the distinguishable frequency data in the image using a reversible weighting factor amongst the rest of the frequencies. The algorithm is designed to shuffle and reverse the sign of each frequency in the transformed image before the image frequencies are transformed back to the pixel domain. The results show a total deviation in pixel values between the original and encrypted image. The decryption algorithm reverses the encryption process and restores the image to its original form. The proposed algorithm is evaluated using standard security and statistical methods; results show that the proposed work is resistant to most known attacks and more secure than other algorithms in the cryptography domain.

• 한국멀티미디어학회논문지
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• 제11권6호
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• pp.764-776
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• 2008

Image identification is the process of checking whether the query image is the transformed version of the specific original image or not. In this paper, image identification method based on feature composition is proposed. Used features include color distance, texture information and average pixel intensity. We extract color characteristics using color distance and texture information by Modified Generalized Symmetry Transform as well as average intensity of each pixel as features. Individual feature is quantized adaptively to be used as bins of histogram. The histogram is normalized according to data type and it is used as the signature in comparing the query image with database images. In matching part, Manhattan distance is used for measuring distance between two signatures. To evaluate the performance of the proposed method, independent test and accuracy test are achieved. In independent test, 60,433 images are used to evaluate the ability of discrimination between different images. And 4,002 original images and its 29 transformed versions are used in accuracy test, which evaluate the ability that the proposed algorithm can find the original image correctly when some transforms was applied in original image. Experiment results show that the proposed identification method has good performance in accuracy test. And the proposed method is very useful in real environment because of its high accuracy and fast matching capacity.

• 한국항해학회지
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• 제13권1호
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• pp.11-20
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• 1989

Radar image data were collected through the on-line data acquisition system of A/D converter and personal computer, and the image was restorated on CRT or plotter after digital image processing of the data. The digital image processing system which was developed for this study, consisted of some kinds of software as follows : rearrangement, transformation, and enhancement of the image data in real space or frequency space by Fourier transform, edge detection of the image, compact processing, state inferential processing, and so on. Since the image of PPI radar sweeps from the center to the circumference of a circle, the image within a given period has the shape of fan. Therefore the acquired data were transformed to have the same interval as that of data in outmost concentricity. The results of various image processing methods using transformed data were better than those of the methods using original data.

• 대한임베디드공학회논문지
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• 제6권3호
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• pp.168-173
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• 2011

In this paper, an optical image hiding technique using real-valued decoding key is proposed. In the embedding process, a each zero-padded original image placed in a quadrants on an input plane is multiplied by a statistically independent random phase pattern and is Fourier transformed. An encoded image is obtained by taking the real-valued data from the Fourier transformed image. And then a phase-encoded pattern, used as a hidden image and a decoding key, is generated by the use of multiple phase wrapping from the encoded images. A transmitted image is made from the linear superposition of the weighted hidden images and a cover image. In reconstruction process, the mirror reconstructed images can be obtained at two quadrants by the inverse-Fourier transform of the product of the transmitted image and the decoding key. Computer simulation and optical experiment are demonstrated in order to confirm the proposed technique.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.243-246
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• 2002

The proliferation of digitized media(audio, image and video) is creating a processing need for copyright enforcement schemes that protect copyright ownership. we argue that a watermark must be placed in perceptually significant components of a signal if it is to be robust to signal distortions and malicious attack. In this paper, RGB coordinate image is transformed into LUV coordinate, it include the characteristics of, Human vision and then the UV component is transformed into NxN block DCT transform. we propose a technique for embedding the watermark of visually recognizable mark into the middle frequency domain of image.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
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• pp.53-56
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• 2000

In progressive image coding, if object region that have main contents in image are transmitted prior to the remained region, this method will be very useful. In this paper, the progressive image coding based on SPIHT using object region transmission method by priority is proposed. First, an original image is transformed by wavelet. Median filtering is used about wavelet transformed coefficient region for extracting object region. This extracted object region encoded by SPIHT. Then encoded object region are transmitted in advance of the remained region. This method is good to a conventional progressive image coding about entire original image. Experimental results show that the proposed method can be very effectively used for image coding applications such as internet retrieval and database searching system.