• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.86-92
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• 2010

This paper proposes a new steganography scheme based on frequency domain using various image frames and collages that can protect the copyright of digital contents for users and securely perform to exchange the security information in the digital communication environments. The main idea of our proposed scheme is that the security informations related its copyright embed into the frequency domain of the image frame and collages when a user decorates the original image by using various image frames and collages. The strengths of our proposed scheme are as follows: (1) It allows to freely control the quantity of embedded information by changing the number of image frames and collages. (2) It is secure to variety image distortion attacks. (3) It maintains high PSNR(Peak Signal to Noise Ratio). As a result, the proposed steganography scheme can be used practically diverse multimedia security fields such as digital copyright protect, secure message communication and digital watermarking.

• The Journal of Korean Association of Computer Education
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• v.6 no.4
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• pp.37-47
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• 2003

In this paper. we propose a new digital watermarking technique which uses the self-similarity of OCT(Discrete Cosine Transform) coefficients for the ownership protection of an image, similar coefficients are classified by SOM(Self-Organizing Map) out of Neural Network. The watermark is inserted into the selected cluster among clusters which consist of coefficients. Generally, the inserted watermark in high frequency regions of an image is eliminated by the compression process such as JPEG compressions, and the inserted watermark in low frequency regions of an image causes the distortion of an image quality. Therefore, the watermark is inserted into the cluster that has many coefficients in the middle frequency regions. This algorithm reduces the distortion of an image quality because of inserting the watermark into an image according to the number of coefficients in selected cluster. To extract watermarks from the watermarked image, the selected cluster is used without an original image. In the experiment, the new proposed algorithm have a good quality and endure attacks(JPEG compressions, filtering. zoom in, zoom out, cropping, noises) very well.

• Imaging Science in Dentistry
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• v.32 no.4
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• pp.213-219
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• 2002

Purpose : Computed radiography (CR) has been used in cephalometric radiography and many studies have been carried out to improve image quality using various digital enhancement and filtering techniques, During CR image acquisition, the frequency rank and type affect to the image quality. The aim of this study was to compare the diagnostic quality of conventional cephalometric radiographs to those of computed radiography. Materials and Methods : The diagnostic quality of conventional cephalometric radiographs (MO) and their digital image counterparts were compared, and at the same time, six modalities (M1-M6) of spatial frequency-processed digital images were compared by evaluating the reproducibility of 23 cephalometric landmark locations. Reproducibility was defined as an observer's deviation (in mm) from the mean between all observers. Results and Conclusion: In comparison with the conventional cephalometric radiograph (MO), Ml showed statistically significant differences in 8 locations, M2 in 9, M3 12, M4 in 7, M5 in 12, and M6 showed significant differences in 14 of 23 landmark locations (p < 0.05). The number of reproducible landmarks that each modality possesses were 7 in M6, 6 in M5, 5 in M3, 4 in M4, 3 in M2, 2 in Ml, and 1 location in MO. The image modality that observers selected as having the best image quality was M5.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.425-431
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• 2009

The purpose of this study was to examine the change of Korean image, product image, purchase intention and revisiting intention according to winning at the global sport event. The intercollegiate students attending in Korea were selected for the sample of this study. The data were analyzed through t-test, Regression Analysis, Reliability Analysis, Frequency Analysis, Confirmatory Factor Analysis using SPSS 12.0. The conclusions of this research are following; First, there would be significant differences of factors - the Korean image, product image, purchase intention and revisit intention - before and after the global sport events. Second, there would be significant differences of factors before and after the global sport events due to the event involvements.

• The Journal of the Korea Contents Association
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• v.2 no.4
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• pp.23-29
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• 2002

This paper suggest the image compression that is needed to process PACS in medical information system. The image decoding method is used Linear-predictor and Lloyd-Max quantizer(quantization) in the Wavelet transform domain. Wavelet Transform Method is processed the multi-resolution by dividing image into 10 sub-bands of 3 levels. Low frequency domain that is sensitive to human visual characteristic is encoded by DPCM which is lossless encoding methods, and Lloyed-Max quantizer, the optimal quantizer for reducing ringing and aliasing in the image of inter sub-band, is used in the remaining high frequency domain of sub-band. The examination verifies that decompressed images are superior by the result that PSNR is 28.53dB on the input image, 512$\times$152 abdominal CT image and Chest image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.949-956
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• 2014

Recently, with the development of hardware and software technology related with image information delivery, the demand for various multimedia service has increased. But, the process of treating, sending, and storing image signals generates image degradation by various external causes. The main cause of image degradation is noise. image is mostly damaged by AWGN (additive white Gaussian noise). Therefore, there have been active researches on noise elimination. This paper, to reduce the effects of AWGN added to the image, suggests a noise-eliminating algorithm which is excellent in low-frequency and high-frequency characteristics in space. And, this paper, through simulation techniques, compared the result of the suggested algorithm with those of the existing methods. And, to evaluate the performance of it, PSNR (peak signal to noise ratio) was used.

• Journal of electromagnetic engineering and science
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• v.17 no.3
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• pp.113-119
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• 2017

The application of compressive sensing (CS) to a radar imaging system based on a frequency-scanned microstrip leaky wave antenna is investigated. First, an analytical model of the system matrix is formulated as the basis for the inversion algorithm. Then, $L_1-norm$ minimization is applied to the inverse problem to generate a range-azimuth image of the scene. Because of the antenna length, the near-field effect is considered in the CS formulation to properly image close-in targets. The resolving capability of the combined frequency-scanned antenna and CS processing is examined and compared to results based on the short-time Fourier transform and the pseudo-inverse. Both simulation and measurement data are tested to show the system performance in terms of image resolution.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.371-374
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• 2000

We propose an efficient method for content-based ultrasound image retrieval using magnitude frequency spectra and implement a retrieval system based on the proposed method. The target images are ultrasound images of adult organs. Trained users often acquire such images so that images of the same kind of organs are very similar, although their locations may not exactly coincide. Therefore, the magnitude frequency spectrum, which has a translation-invariant property, is used as a feature. All the object images in the image DB is pre-classified in the same kind organs. Experimental results show that the proposed method is superior to some well-known conventional methods.

• Journal of Fashion Business
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• v.2 no.4
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• pp.112-125
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• 1998

This study is to grasp the variousness of clothing worn by elderly women with the ideal self-image by group and by finding out the characteristics of higher-image groups and lower-image group. The object of this study was a total of 488 elderly women above full 55 from an elderly women and who lived in downtown Pusan ionnaire. For statistical disposition, the analysis of factors and frequency was carried out. The results of this study are as follows : 1. As a result of the analysis of realistic self-image and ideal self-image, the realistic self-image was derived as 5 factors-voguishness, loftiness, freshness, feminality, activeness and the ideal self-image as 4 factors-activeness, loftiness, feminality, voguishness. 2. The perceptive age according to age in the realistic self -image reflects that though the 50' s percept the 50' s, the 60' s percept the 50' s and the 70' s the 60' s and also in the ideal self-image, it shows the same result. 3. The degree of satisfaction of build in the realistic self-image appeared that the 50's unsatisfied, the 60's and the 70's felt so, and in the ideal self-image, the 50's and 60's unstisfied, the 70's so. 4. The ideal image according to age in both the realistic self-image and the ideal self-image of clothing appeared that all the 50' sand 60' s wanted a good impression and the 70' s wanted a gentle impression. 5. The frequency of doing a make-up by age in all elder women according of the realistic self-image of clothing showed that the case of doing a make-up when going out only was the greatest number and also in the ideal self-image, it agrees to the same.

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.729-736
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• 2005

In this paper. the proposed method for the digital watermarking is based on the multiresolution wavelet transform. The 1-level Discrete Wavelet Transform(DWT) coefficients of a $2N_{wx}{\times}2N_{wy}$ binary logo image used as a watermarks. The LL band and middle frequency band of the host image that the 3-level DWT has been performed are divided into $N_{wx}{\times}N_{wy}$ size and we use large coefficients at the divided blocks to make threshold. we set the thresholds that completely insert the watermark in each frequency of the host image. The thresholds in each frequency of the host image differ each other. The watermarks where is the same positions are added to the larger coefficients than threshold in the blocks at LL band and middle frequency band in order to prevent the quality deterioration of the host image. The watermarks are inserted in LL band and middle frequency band of the host image. In order to be invisibility of the watermark, the Human Visual System(HVS) is applied to the watermark. We prove the proper embedding method by experiment. We rapidly detect the watermark using this watermarking method. And because the small size watermarks are inserted by HVS, the results confirm the superiority of the proposed method on invisibility and robustness.