• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7C
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• pp.716-725
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• 2005

In this paper, we propose a new approach for the reduction of the dynamic false contours, which detects and compensates false contour artifacts adaptively. First, we develop a simple but effective method to select the pixels that are likely to cause the motion artifacts, based on the distribution of pixel values. Then, we merge the selected pixels into several regions using tree structure. Next, we reduce number of gray levels within the regions slightly to reduce the false contours. Note that reducing number of gray levels yield the distortion, thus it is applied only to the selected regions, instead of the whole picture. Intensive simulations on real moving image show that the proposed algorithm alleviates the dynamic false contours effectively with tolerable computational complexity.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.189-191
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• 2008

Hold-type display의 동화상 인식 원리를 이용하여 인간의 시각특성을 고려한 동화상 노이즈 컴퓨터 시뮬레이터를 개발하였다. 그리고 이 시뮬레이터를 이용하여 PDP의 동화상 노이즈인 의사윤곽 노이즈의 서브필드 배열과 속도 의존성에 대해 실험하였다. 실험 결과 기존의 서브필드 배열 방식은 의사윤곽 노이즈를 저감시킬 수가 있으나 화상의 이동속도가 빠를수록 노이즈가 증가하는 것을 알 수 있어 근본적인 대책이 될 수 없다는 것을 알았다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.3
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• pp.113-120
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• 2003

Plasma display panels normally utilize the binary coded light emission scheme for gray scale expression. Subsequently, this expression method makes dynamic false contours. We propose the "E3DSM(enhanced 3-dimension scattering method)" that improved existing 3-d scattering method and the "HAM(histogram analysis method)" that is decided the driving schemes and subfield selections with histograms of images. Simulation results show the improving image quality.

• Journal of Broadcast Engineering
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• v.15 no.5
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• pp.697-702
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• 2010

Contour artifact is known as the unintentional result of quantizing a flat area that has smooth gradients. In this letter, a decontouring algorithm is proposed to efficiently remove false contours that occur in typical block-based video coding applications. First, the algorithm goes through a refinement stage to determine candidate blocks probably having noticeable false contours with different kinds of features in a block. Then, pseudo-random noise masking is applied to those blocks to mitigate the contour artifacts. This block-based selective decontouring can efficiently remove the unnecessary processing of those blocks that have no false contour, which incidentally ensures a minor penalty in visual quality and computational complexity. The proposed algorithm was demonstrated, integrated into H.264/AVC, that visual quality can be significantly enhanced with an ignorable rate-distortion (RD) loss and an minor increase in computational complexity.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.1
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• pp.1-8
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• 2004

We developed a new PDP gray scale implementation method on the basis of the quantized memory addressing(QMA) principle. We defined three wall charge states; 'fully-on', 'off', and 'half-on', by controlling the width of address pulses. With these three wall charge state, we were able to express 255 level gray scale with only 7 sub-fields. Furthermore, in contrast to the conventional driving methods, the sub-field combinations for any two adjacent gray levels differ by only 1 sub-field, at worst, and therefore, eliminate the dynamic false contours. Since this method use 7 sub-field, the sustain discharge Period is increased by more than $70\%$ compared to the 12 sub-field method which reduces the dynamic false contours.

• The Journal of the Korean dental association
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• v.46 no.5
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• pp.284-288
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• 2008

• The Journal of the Korean dental association
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• v.46 no.5
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• pp.289-294
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• 2008

• The Journal of the Korean dental association
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• v.32 no.1 s.296
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• pp.9-10
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• 1994

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1177-1180
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• 2000

본 논문은 영상처리의 전처리 과정에서 많이 쓰이는 윤곽선 추출 알고리즘을 이용하여 각종 공격에 강인한 디지털 워터마킹 기법을 제안한다. 윤곽선은 영상의 특징을 결정하는 중요한 요소이기 때문에 이를 워터마크 시퀀스로 이용함으로써 기존 가우시안 랜덤 시퀀스나 의사 랜덤 시퀀스 보다 더 효과적인 시퀀스를 생성할 수 있다. 이를 증명하기 위해 다양한 공격 형태를 가지고 실험해 봄으로써 제안한 방법의 타당성을 검증한다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1619_1620
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• 2009

실험용 PDP에 동화상 계조 바를 구현하고 이를 추적 촬영하는 동화상 의사윤곽 노이즈 측정/평가 시스템을 개발하였다. 측정결과, 계조 바의 배열에 따라 두 계조 바의 경계에 어둡거나 밝은 띠의 노이즈가 나타났으며, 화소의 이동속도가 빨라질 경우 노이즈의 범위가 확대됨을 확인 할 수 있었다. 또한 노이즈는 CCD 센서를 정지시켰을 경우에는 측정되지 않았다. 이것은 기존의 연구결과와도 잘 일치하므로 본 연구에서 개발한 측정 시스템은 PDP의 의사윤곽 노이즈를 정량적으로 평가하는 데 유용하다.