• Journal of Institute of Control, Robotics and Systems
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• v.8 no.6
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• pp.462-467
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• 2002

A new approach for reducing the blocking artifact is proposed in this paper. This method can be applied to conventional transform coding, without introducing additional information or significant blurring. Main drawbacks of the Discrete Cosine Transform(DCT) are visible block boundaries due to coarse quantization of the coefficients. Therefore, restoration techniques result in unnecessary blurring of the image. The proposed deblocking algorithm is based on the heuristic approach for edge detection. All edges of the standard still images are categorized, and the best edges are selected. Several images are used fer experiments, and several other previous algorithms are compared with the proposed approach. The results show that the proposed algorithm works better than those of other previous researches. This algorithm can be used for JPEG, MPEG, and H.261 standard images.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.9
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• pp.1410-1419
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• 1989

In this paper, we present a new synthetic high coding method which gives high image compression ratio. Given an image, only its low-pass component is transmitted by DCT coding` the high-pass component is not transmitted but synthesized using edge sharpening on the reconstructed low-pass image at the receiver. For the DCT coding which is used to encode the low-pass image, we used an improved version of Cox's variance estimator. Also, introduced are new image quality measures called GSNR and EPR which emphasize perceptual aspects of image quality. Experimental results show that the performance of the proposed synthetic high coding is better in various quality measures than that of Cox's adaptive transform coding. Also, it yields acceptable image quality with neither apparent block effect nor visible granular noise even at high compression ratio of about 30:1.

• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.62-65
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• 1999

Iron regulatory proteins (IRPs) 1 and 2 bind with equally high affinity to specific RNA stem-loop sequences known as iron-responsive elements (IRE) which mediate the post-transcriptional regulation of many genes of iron metabolism. To study putative IRE-like sequences in RNA transcripts using the IRP-IRE interaction, Eight known genes from database were selected and the RNA binding activity of IRE-like sequences were compared to IRP-2. Among them, the IRE-like sequence in 3'-untranslational region (UTR) of divalent ration transporter-1 (DCT-1) shows a significant RNA binding affinity. This finding predicts that IRE consensus sequence present within 3'-UTR of DCT-1 might confer the regulation by IRP-2.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.06a
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• pp.25-29
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• 1997

The present block-based DCT encoder transforms images regardless of layers and then simply partitions the transformed data into a few layers, for example low and high frequency bands in JPEG. Yet, it fails to utilize the similarity of coefficients in each band. Therefore, we combine the subband coder and the block-based DCt coder in this paper. The new coding scheme enables the data to automatically be classified into several layers and increases the efficiency of transform. Various possible coding structures are investigated and the simulation results are also provided.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1790-1806
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• 2016

Digital image encryption is widely used for image data security. JPEG standard compresses image with great performance on reducing file size. Thus, to encrypt an image in JPEG format we should keep the quality of original image and reduced size. This paper proposes a JPEG image encryption scheme based on quantized DC and non-zero AC coefficients inner category scrambling. Instead of coefficient value encryption, the address of coefficient is encrypted to get the address of cipher text. Then 8*8 blocks are shuffled. Chaotic iteration is employed to generate chaotic sequences for address scrambling and block shuffling. Analysis of simulation shows the proposed scheme is resistant to common attacks. Moreover, the proposed method keeps the file size of the encrypted image in an acceptable range compared with the plain text. To enlarge the cipher text possible space and improve the resistance to sophisticated attacks, several additional procedures are further developed. Contrast experiments verify these procedures can refine the proposed scheme and achieve significant improvements.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.315-318
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• 2002

본 논문은 워터마크의 일반 요건 중에서 가장 기술적으로 요구되는 강인성과 비인지성을 함께 발전시키기 위해서 구성되었다. 먼저, 주파수 영역을 이용한 워터마킹 기법 중에서 현재 압축 표준에서 사용되고, 지역적 인간 시각 시스템을 이용할 수 있기 때문에, 널리 사용되는 블록 단위의 DCT를 사용한다. 삽입 위치를 결정하기 위하여, 기존에 발표된 논문들의 강인성을 비교하여, 보다 나은 위치를 선정한다. 그리고, 인간 시각 시스템 중에서, 강한 에지의 인지성을 줄이기 위하여, 에지의 오리엔테이션을 보존하고 수평과 수직 성분보다는 45 도에 가까운 DCT 대각 성분에 워터마크의 강도를 높여준다 이는 워터마크 이후의 강한 에지 성분의 오리엔테이션 오차를 줄여주며, 에지의 비인지성을 향상시키는 결과를 가져온다.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1823-1826
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• 2002

On modern computer culture, the high quality data is required in multimedia systems. So, the technology of data compression fur data transmission is necessary now. This paper presents the pipeline architecture for the low and column address generator of 2D DCT/IDCT (Discrete Cosine Transform/Inverse Discrete Cosine Transform. In the proposed architecture, the area of hardware is reduced by using the DA (distributed arithmetic) method and applies the concepts of pipeline to the parallel architecture. As a result the designed pipeline of the low and column address generator for 2D DCT/IDCT architecture is implemented with an efficiency and high speed compared with the non-pipeline architecture.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.41-45
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• 2011

This paper presents a fire detection criterion based on flame color, spatial and temporal characteristic analysis of color fire images. To propose the criterion, Firstly the fire candidate regions were selected by using analyzed Cr and Y threshold value, and then texture analysis of candidate regions was performed by using DCT. Finally variation of Y values of these regions was calculated for temporal analysis. The proposed fire detection criterion was simulated by using fifteen test images and practicality was verified.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1585-1588
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• 2015

본 논문은 human visual system(HVS)에 따른 주파수 민감도와 공간에서 다양한 특성들을 구현하기 위한 신호처리 방법을 개발하였다. 인간의 눈은 주파수 성분에 따라 민감도가 다르며 초점에서 멀수록 인지 가능한 해상도가 떨어진다. 주파수 민감도를 구현하기 위해서 본 논문은 영상 신호의 에너지 스펙트럼 모양이 contrast sensitivity function(CSF)의 모양이 되도록 하여 영상 신호의 에너지를 증가시켰으며 신호 방향에 적응적인 multiband energy scaling 방법을 개발하였다. 기존의 시스템에서 능률만을 향상시키는 기존의 분석 모델과 비교하면 개발한 방법은 HVS에 좀 더 적절하고 선호되게 영상 신호를 처리할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1169-1172
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• 2010

대부분의 홍채인식 시스템의 전반부를 살펴보면 카메라를 통한 이미지를 획득 후 전처리 과정에서 동공의 경계를 잡는 과정이 수행된다. 카메라를 통한 이미지 획득 시 초점이 좋은 이미지와 나쁜 이미지가 같이 획득이 된다. 초점이 나쁜 이미지는 동공의 경계를 잡는 과정에 있어서 좋은 이미지보다 시간이 오래 걸리기 마련이다. 이에 본 논문에서는 영상획득 후 동공의 경계를 잡는 과정 전에 DCT(Discrete Cosine Transform)를 이용한 선명도 측정하는 방법을 제안한다. 카메라를 통한 영상을 획득한 후 초점이 좋은 영상과 나쁜 영상을 구분하게 되고 초점이 좋은 영상만을 선택하여 다음 과정인 동공의 경계를 잡는 작업을 수행하게 된다. 제안하는 방법은 DCT를 이용한 이미지의 선별 작업에 시간이 소비 되지만 나쁜 영상을 이용하여 동공의 경계를 잡느라 걸리는 시간을 줄일 수 있는 장점을 기대할 수 있다. 우선적으로 수학적 분석을 통하여 23%의 속도 절감을 통한 성능 개선의 가능성을 보였고, 실제 구현을 통하여 속도 향상이 기대된다.