• Journal of KIISE:Software and Applications
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• v.30 no.7_8
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• pp.687-695
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• 2003

In this paper, we present a document image compression system based on segmentation, Quincunx downsampling, (5/3) wavelet lifting and subband-oriented SPIHT coding. We reduced the coding time by the adaptation of subband-oriented SPIHT coding and Quincunx downsampling. And to increase compression rate further, we applied arithmetic coding to the bitstream of SPIHT coding output. Finally, we present the reconstructed images for visual comparison and also present the compression rates and PSNR values under various scalar quantization methods.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.155-164
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• 2014

Local histogram equalization is one of the most popular ways of enhancing the local brightness features of an input image. However, local histogram equalization reveals some problems. First, undesired artifacts are produced by over-enhancing the local features. Second, the enhancement of local features does not always result in global contrast enhancement. To cope with these problems, we propose an illumination driven local histogram equalization method. First, to estimate the illumination information, the proposed method combines the input image and the blurred image produced through the process of the down-sampling and the up-sampling. Next, the proposed method adaptively adjusts the mapping function estimated by the local histogram equalization using the information of the illumination. As a result, the proposed illumination information driven local histogram equalization method simultaneously enhances the global and the local contrast levels while preventing any local artifacts. Experimental results show that the proposed algorithm outperforms the conventional methods on objective and subjective criteria.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.294-302
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• 2008

In this paper, we present a new image up-sampling method which registers low resolution images to the high resolution grid when Bayesian super-resolution image processing is performed. The proposed up-sampling method interpolates high-resolution pixels using high-frequency data lying in all the low resolution images, instead of up-sampling each low resolution image separately. The interpolation is based on B-spline non-uniform re-sampling, adjusted for the super-resolution image processing. The experimental results demonstrate the effects when different up-sampling methods generally used such as zero-padding or bilinear interpolation are applied to the super-resolution image reconstruction. Then, we show that the proposed hybird up-sampling method generates high-resolution images more accurately than conventional methods with quantitative and qualitative assess measures.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.331-334
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• 2002

의사잡음 시퀀스를 이용한 대역확산 기반의 오디오 워터마킹은 들리지 않으면서도 강인한 워터마크를 만들기 위해 심리음향모델이나 고정필터를 사용하여 의사잡음 시퀀스를 변형시킨다. 그런데, 이러한 방법을 이용하여 스펙트럼 변형된 의사잡음은 고주파 영역에 대부분의 에너지를 갖게 되므로 인위적으로 오디오 신호의 고주파 영역을 잘라내는 공격에 취약하다는 단점이 있다. 본 논문에서는 이러한 단점을 보안하고 강인성 및 잡음의 최소화를 위하여 중간값의 성질을 이용하여 의사잡음을 변형 후 삽입하는 워터마킹 시스템을 제안한다. 중간값 성질을 이용하여 변형한 의사잡음은 원 오디오 신호와의 상관성이 높으며 전주파수 대역에 고르게 분포하는 성질이 있으므로 고주파 영역의 공격에 강인하다. 제안 방법은 의사잡음의 고유성질을 최대로 살린 방법으로 각종 오디오 부호화, 부가잡음, 다운/업 샘플링, 채널변경, 진폭 공격과 같은 다양한 공격에도 워터마크 신호의 검출이 가능하다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.4
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• pp.49-57
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• 2012

This paper presents a fast multiple-image-based deblurring method that decreases the computation loads in the image deblurring, enhancing the sharpness of the textures or edges of the restored images. First, two blurred images with some blurring artifacts and one noisy image including severe noises are consecutively captured under a relatively long and short exposures, respectively. To improve the processing speeds, the captured multiple images are downsampled at the ratio of two, and then a way of estimating the point spread function(PSF) based on the image or edge patches extracted from the whole images, is introduced. The method enables to effectively reduce the computation time taken in the PSF prediction. Next, the texture-enhanced image deblurring method of supplementing the ability of the texture representation degraded by the downsampling of the input images, is developed and then applied. Finally, to get the same image size as the original input images, an upsampling method of utilizing the sharp edges of the captured noisy image is applied. By using the proposed method, the processing times taken in the image deblurring, which is the main obstacle of its application to the digital cameras, can be shortened, while recovering the fine details of the textures or edge components.

• Journal of Broadcast Engineering
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• v.24 no.3
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• pp.401-410
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• 2019

In this paper, we propose a reference picture generation method for Inter-layer prediction based deep learning to improve the SHVC coding performance. A description will be given of a structure for performing filtering using a VDSR network on a DCT-IF based upsampled picture to generate a new reference picture and a training method for generating a reference picture between SHVC Inter-layer. The proposed method is implemented based on SHM 12.0. In order to evaluate the performance, we compare the method of generating Inter-layer predictor by applying dictionary learning. As a result, the coding performance of the enhancement layer showed a bitrate reduction of up to 13.14% compared to the method using dictionary learning, a bitrate reduction of up to 15.39% compared to SHM, and a bitrate reduction of 6.46% on average.

• Journal of Broadcast Engineering
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• v.17 no.1
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• pp.108-121
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• 2012

As Scalable Video Coding (SVC) is a video compression standard extended from H.264/AVC, it is a way to provide scalability in terms of temporal, spatial and quality. Although the compression efficiency of SVC is increased due to the scalability in many aspect, it is essential to reduce the complexity in order to efficiently use because the complexity is relatively increased. To reduce the complexity of SVC in the paper, we propose fast mode decision algorithm to reduce the complexity of encoding process using direction information of B-picture by efficiently performing inter-layer prediction. The proposed algorithm is a fast mode decision algorithm that makes different from detection mode number of forward and backward, bi-direction in the way using best mode of base-layer up-sampled after simply SKIP mode detection using the direction information of best mode of base-layer up-sampled. The experimental results show that the proposed algorithm approach can achieve the maximum computational time saving about 53% with almost no loss of rate distortion (RD) performance in the enhancement layer.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.275-276
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• 2009

This paper provides a new approach for predicting the corrosion resistivity of reinforced concrete structures exposed to carbonation. In this method, the prediction can be updated successively by a Bayesian theory when additional data are available. The stochastic properties of model parameters are explicitly taken into account into the model. To simplify the procedure of the model, the probability of the durability limit is determined from the samples obtained from the Latin hypercube sampling technique. The new method may be very useful in designing important concrete structures and help to predict the remaining service life of existing concrete structures which have been monitored.

• Proceedings of the Safety Management and Science Conference
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• 2013.11a
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• pp.9-23
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• 2013

건설공사는 인력의존도가 가장 높으며 타 산업에 대비하여 자동화가 매우 낮고 외기에 노출된 작업 환경으로 추락 등의 중대재해 위험이 가장 높은 산업이다. e-나라지표에 의하면 2006년부터 2012년까지 전체 산업의 약 21.9%를 차지하는 건설 근로자가 생산 활동에 종사하고 있으며, 이직 및 인력의 이동이 매우 잦은 특성을 갖고 있다. 2006년~2012년까지의 재해발생 통계에 따르면 전체적으로 타 산업은 매년 다소간의 증감은 있으나 재해가 감소하는 추세이지만, 건설공사의 경우는 지속적으로 증가하고 있다. 특히, 사고성 사망재해의 경우는 7년간 전체 산업에서 발생하는 사고성 사망재해의 평균 40.9%를 건설업이 차지하고 있어 가장 높아 매우 심각한 수준이다. 또한 건설현장과 건설회사의 안전보건경영의 운영방법 및 제도가 매우 단순하고 정성적인 수준으로 타 산업에 비하여 안전경영의 정량화에 대한 노력이 매우 미약하다. 과거 재해사례 및 통계를 분석하여 앞으로의 재해 위험 요소를 제거하거나 안전한 상태로 형성하여야 하나, 발표되는 재해사례나 통계를 구호 또는 슬로건으로 전파, 교육하는 수준에 머물고 있다. 본 연구에서는 아파트공사를 대상으로 2006년~2011년의 과거 재해통계(8,687건)를 분석하여 데이터베이스화하고, 실제 공사한 아파트공사 샘플현장의 자료(89,375명)를 데이터베이스화하여 현 실정에 부합한 정량적 직종별 위험도를 산정하는 연구를 진행하였다. 따라서 아파트공사의 직종별 위험도를 정량적인 데이터로 산출하고, 과학적인 방법으로 현장 위험수준을 실시간 모니터링 함으로써 건설현장의 주된 생산력인 근로자의 생명과 건강을 보호할 수 있는 효과적인 재해예방이 이루어 질 것으로 기대된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1777-1783
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• 2013

We do research on the simulation of Doppler effect from a target's moving under the sea by Transmission Line Matrix modeling which is one of numerical methods on time domain. To implement the effect, the input signal was entered at a moving node according to a moving target's moving speed. The result had maximum 2.47% error compared with the theoretical value. And from simulation results with speed control of a moving target, we could also obtain resonable results within 0.63% error range.