• Journal of Korea Multimedia Society
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• v.3 no.4
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• pp.365-371
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• 2000

To restore image degraded by out-of-focus blur and additive noise, an iterative restoration is used. Acceleration parameter is usually applied equally to all over the image without considering the local characteristics of degraded images. As a result, the conventional methods are not effective in restoring severely degraded edge region and shows slow convergence rate. To solve this problem we propose an adaptive iterative restoration according to local degradation, in which the acceleration parameter has low value in flat region that is less degraded and high value in edge region that is more degraded. Through experiments, we verified that the proposed method showed better results with fast convergence rate, showed Visually better image in edge region and lower MSE than the conventional methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.139-143
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• 2021

본 논문에서는 꾸준히 연구되어 오던 이미지 복원 문제에서 초해상화와 인페인팅이라는 복합적 이미지 복원을 동시에 처리하는 해결 방법을 제안한다. 초해상화는 국지적 픽셀 정보를 이용하여 고해상도의 영상을 복원하고, 인페인팅은 이미지 전체 정보를 활용하여 영상 내 비어 있는 영역을 생성해야 하므로, 이러한 두 가지 영상 복원 기법을 동시에 수행하는 것은 상당히 어려운 문제이다. 그렇기에 인페인팅과 초해상화는 이미지 복원에서 널리 활용되는 기술인 만큼 동시에 해결할 수 있는 기법에 대한 수요는 있음에도 지금까지 거의 연구되지 않았다. 본 논문은 초해상화 및 인페인팅 합동 처리에 있어 복합적인 정보를 모두 다뤄야하는 네트워크가 서로의 성능을 저하시키지 않도록 개략적 복원 네트워크 (Coarse network), 디테일 복원 네트워크 (Refinement network), 초해상화 네트워크 (SR network)로 분리하여 초해상화 및 인페인팅 합동 처리를 수행하며, 각 단계마다 결과 영상을 얻어 스케일 별 정답 영상과 손실함수를 계산하여 복합적인 성능을 올릴 수 있는 방법을 제시한다. 또한 순차적 단일 모델에 비하여 인페인팅과 초해상화를 합동 학습하는 제안 모델이 개선된 화질의 결과 영상을 획득할 수 있다는 것을 실험적으로 보인다.

• Journal of Broadcast Engineering
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• v.19 no.1
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• pp.109-117
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• 2014

This paper presents a superresolution restoration technique that can restore high-resolution images from differently blurred low resolution images rather than using the motion information between low-resolution images. In order to restore the super-resolution image the rotatable aperture mask lens system is proposed. The proposed technique does not need to estimate point spread function at each frame. In addition, it does not require image registration because there is no global translational motion between low resolution images. By using a rotatable rectangular aperture, two consecutive captured images provide sufficiently exclusive information for superresolution. Therefore, the proposed method can reduce the registration error between the low-resolution image as well as the calculation amount for superresolution restoration. The existing lens system of the camera can be extended to obtain a superresolution image by only adding an rotatable rectangular aperture mask. Finally, in order to verify the performance of the proposed system, experimental results are performed. By comparing with the existing superresolution methods, the proposed method showed the significant improvements in the sense of spatial resolution.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.81-85
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• 1998

점확산 함수(point spread function; PSF)의 정확한 추정은 복원결과가 원 영상에 얼마나 근접할 수 있는가를 결정한다는 점에서 영상처리의 중요한 연구 주제중의 하나가 된다. 본 논문에서는 PSF를 추정하기 위한 알고리즘을 제안하고, 이를 영상복원에 적용한 후 이를 기반으로 디지털 자동초점시스템을 제안한다. 초점불안전 열화시스템을 구현하기 위한 과정은 두 단계로 구성되어 있는데, 즉 입력 영상에서 에지분류를 통한 PSF 추정과, 이를 이용한 영상복원이다. 보다 구체적으로, 입력 영상에 특정 에지가 있는 임의의 크기의 블록을 선정해부면, 그 블록으로부터 자동으로 에지방향이 기저영상을 이용해서 구해지며 확산원의 크기를 추정하여 1차원 단위 계단응답과 영역을 구하여 평균한 후, 2차원 등방성 PSF를 추정한다. 마지막으로 추정된 PSF를 사용하여 복원을 수행함으로써 초점이 맞는 영상을 구한다.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.308-318
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• 2004

A subject to recognize the damaged facial image is becoming an important issue in commercialization of automatic face recognition. The method to recognize a face on a damaged image is divided into two types. The one is to recognize remainders after removing the damaged information and the other is to recognize a total face after recovering the damaged information. On this paper, we present the reconstruction method by analyzing the main materials after extracting the damaged region through Kohonen network. The suggested algorithm in this paper estimates feature vectors of the damaged region using eigen-faces in PCA and then reconstructs the damaged image. This allows also the reconstruction under the untrained images. Through testing the artificial images where the eye and the mouth which have many effects to face recognition are damaged, the recognition rate of the proposed results showed similar results with the method which used Kohonen network, and improved about 11.8% more than symmetrical property method. Also, in case of the untrained image, our results improved about 14% more than that of the Kohonen method and about 7% more than that of the symmetrical property method.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.1
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• pp.1-8
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• 2004

It's a very meaningful experimental study to image restoration of ancient villages vanished at the real life spatial world. Focused on Cheung-Pyung Lake around where most part were flooded by the Chung-Ju large dam founded in early 1980s, we used remote sensing technique in this study in order to restore topographical features before the flood with 3 dimensional effects. It was gathered comparatively good satellite photos and remotely sensed digital images, then its made a new color image from these and the topographical map which had been made before filled water. This task was putting together two kinds of different timed images. And then, we generated DEM(digital elevation model) including the outskirts of that area as harmonizing current contour lines with the map. That could be a perfect 3D image of Cheung-Pyung around before when it had been flood by making perspective images from all directions, north, south, east and west, for showing there in three dimensions. Also, flying simulation we made for close visiting can bring us to experience their real space at that time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.272-282
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• 2004

This paper introduces a regularized mixed norm multi-channel image restoration algorithm using both within-and between- channel deterministic information. For each channel a functional which combines the least mean squares (LMS), the least mean fourth (LMF), and a smoothing functional is proposed. We introduce a mixed norm parameter that controls the relative contribution between the LMS and the LMF, and a regularization parameter defining the degree of smoothness of the solution, where both parameters are updated at each iteration according to the noise characteristics of each channel. The novelty of the proposed algorithm is that no knowledge of the noise distribution for each channel is required and that the parameters mentioned above are adjusted based on the partially restored image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1853-1859
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• 2008

In this paper, we propose a novel method to improve the visual quality of reconstructed images for 3D pattern recognition based on the computational integral imaging reconstruction (CIIR). The proposed CIIR method provides improved 3D reconstructed images by superimposing magnified elemental images by a combination of a round mapping model and image interpolation algorithms. To objectively evaluate the proposed method, we introduce an experimental framework for a computational pickup process and a CIIR process using a Gaussian function and evaluate the proposed method. We also carry out experiments on 3D objects and present their results.

• Journal of the Korea society of information convergence
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• v.1 no.1
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• pp.17-24
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• 2008

Video camera play very important roles for preventing many kinds of crimes and resolving those crime affairs. But in the case of recording image of a specific person far from the CCTV, the original image needs to be enlarged and recovered in order to identify the person more obviously. Interpolation is usually used for the enlargement and recovery of the image in this case. However, it has a certain limitation. As the magnification of enlargement is getting bigger, the quality of the original image can be worse. This paper uses FOP(Facial Definition Parameter) proposed by the MPEG-4 SNHC FBA group and introduces a new algorithm that uses face outline information of the original image based on the FOP, which makes it possible to recover better than the known methods until now.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.743-746
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• 2001

멀티미디어 정보 중 비디오 데이터는 정보량이 많기 때문에 자동화된 비디오 영상 처리 기술이 필요하다. 시청자의 이해와 시청의 편의성을 제공하기 위하여 대부분 비디오에 자막을 삽입하게 된다. 외국 방송물 및 영화에 삽입된 다른 언어 자막을 편집 과정에서 자막으로 교환 할 필요성이 종종 있게 된다. 기존의 방법들은 자막 부분을 충분히 포함하는 일정 영역에 특정 색상을 채운 후 새로운 자막을 삽입하게 된다. 기존 방법의 문제점은 많은 영역에 대해 비디오 영상 정보를 손실 시킴으로써 시청자에게 시청의 불편을 초래하고 자막 교환의 비 효율성과 부 자연스러움을 발생시킨다. 본 논문에서는 기존 방법의 문제점을 극복하기 위하여 자막 영역을 원영상으로 복원한 후 다른 자막으로 교환하는 방법을 제안하고자 한다. 원영상 복원을 위하여 비디오 정보와 BMA(Block Matching Algorithm)를 이용한 원영상 복원 방법을 제안하고, 복원된 영역에 다른 자막으로 교환함으로써 효과적인 자막 교환 방법을 제안하고자 한다. 실험 결과 원영상 복원을 이용한 자막 교환 방법은 기존 방법에 비해 자연스럽고 효과적인 교환 방법임을 볼 수 있었다.