• The Journal of the Korea Contents Association
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• v.7 no.9
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• pp.72-80
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• 2007

Image magnification is the estimation of a few pixel in images with high quality from a pixel of an image with low resolution and there have been studied many techniques to make images with high quality. In this paper, we propose an image interpolation method using median filter and spatial information. The proposed method makes an interpolating pixel using an average value of a median filtered value and an average value of two pixels correlated with an interpolating pixel tightly. Also we make the magnified image with improved quality to add the directional information of surrounding pixels and the characteristic of ones using average value and max value of spatial variation. We evaluate the performance using PSNR in the quality of enlarged image comparing the proposed method with existing methods. The results show the proposed method improves PSNR than the existing methods and make images preserving the characteristic of original imges.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.3-13
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• 2010

In this paper, we propose a method for filling out the occlusions in generating multi-view images from one source image and its ground-truth depth image. The method is based on image inpainting and layered interpolation. The source image is first divided into several layers using depth information. The occlusions are interpolated separately in every layered image using the image inpainting algorithm. Finally, the interpolated layered images are combined to obtain different viewpoint images. Interpolating occlusions with depth-correlated texture information that is contained to each layer makes it possible to obtain more detailed and accurate results than previous methods. The effectiveness of the proposed method is shown through experimental results.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.8-10
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• 2011

3D 콘텐츠를 획득하는 여러 가지 방법 중 2D-plus-Depth 구조는 다시점 영상을 얻을 수 있는 장점 때문에 최근 이에 관한 연구가 활발히 진행되고 있다. 이 구조를 통해서 고품질의 3D영상을 얻기 위해서는 무엇보다 고품질의 깊이 영상을 구현하는 것이 중요하다. 깊이 영상을 얻기 위해서 Time-of-Flight(ToF)방식의 깊이 센서가 활용되고 있는데 이 깊이 센서는 실시간으로 깊이 정보를 획득할 수 있지만 낮은 해상도와 노이즈가 발생한다는 단점이 있다. 따라서 깊이 영상의 특성을 보존하는 상환 변환을 하여야지만 고품질의 3D 콘텐츠를 제작할 수 있다. 주로 깊이 영상의 해상도를 높이기 위해서 Joint Bilateral Upsampling(JBU) 방식이 사용되고 있다. 하지만 이 방식은 4배 이상의 고 해상도 깊이 영상을 획득하는 데에는 적합하지 않다. 따라서 고해상도의 깊이 영상을 얻기 위해서 보간법을 수행하여 가이드 영상을 만든 후 Bilateral Filtering(BF)을 처리함으로써 영상의 품질을 향상시킨다. 본 논문에서는 2D-plus-Depth 구조에서 얻은 컬러 영상과 깊이 영상을 결합한 보간법을 통해서 깊이 영상의 특성을 살린 가이드 영상을 구현하는 방법을 제안한다. 실험 결과는 제안 방법이 기존 보간법보다 경계 영역 및 평활한 영역에서 깊이 영상의 특성을 잘 보존하는 것을 보여준다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.1005-1007
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• 2017

본 논문에서는 어안렌즈를 통해 획득한 전방향 영상을 파노라마 영상으로 변환하기 위한 영역분할 방법을 제안한다. 각 분할된 영역에 대한 변환 과정에서 발생하는 영상 왜곡을 완화하면서 에지를 보존하기 위하여 기존 양성형 보간 방법을 대체하는 바이래터럴 필터 보간 방법을 제안한다. 또한 파노라마 변환 영상에서 본 논문의 제안방법의 결과가 기존 결과보다 에지가 잘 보존됨을 확인하였다.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.109-110
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• 2007

본 논문에서는 베이시안 초해상도 영상처리시 저해상도 영상들을 고해상도 격자에 맞게 정합해서 업샘플링(upsampling)을 하는 새로운 방식에 대해 제안한다. 제안하는 업샘플링 방식은 각 장을 따로 보간하는 방식과 달리 여러 저해상도 영상의 고주파 정보가 고해상도 영상 격자의 모든 위치에 적절히 영향을 미칠 수 있도록 여러 장의 저해상도 영상의 고주파 정보를 함께 사용하여 보간한다. 보간하는 방법은 B-스플라인 (B-Spline) 기반 비정규 리샘플링(non-uniform resampling)을 기반으로 초해상도 영상처리에 맞도록 적용한다. 실험결과를 통해 일반적으로 적용되는 0-삽입(zero-padding) 업샘플링 방식과 쌍일차 보간법(bilinear interpolation) 등을 적용할 때의 효과를 살펴보고, 제안하는 방식이 일반적인 방식을 사용하는 것에 비해 정량적, 정성적으로 고해상도 정보를 더 정확히 생성해내는 것을 확인한다.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.865-869
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• 2009

An image resolution enhancement is mainly utilized as pre-processing technique for various image processing application. It requires to decrease image quality deterioration such as blurring. In this paper, we propose an image resolution enhancement algorithm using low level interpolation. In the proposed algorithm, we calculate an error using low level interpolation, estimate an error image from the calculated error. The estimated error image is added interpolated high resolution image, it become lastly reconstruction image. Our experiments obtained the average PSNR about 1dB which is improved results better than conventional method for sensitive image quality. Also, subjective image quality with edge region is more clearness. The proposed method may be helpful for applications in various multimedia systems such as image restoration.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.59-67
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• 2012

In this paper, an efficient interpolation scheme using gradient information between adjacent pixel values was proposed to estimate the value of interpolated pixel to have the locality which exists in real image and the characteristic of simple convex surface and simple concave surface which exist partially in the real image. PSNR(Peak Signal to Noise Ratio) was used to evaluate the performance of the proposed scheme. The PSNR values of the magnified images using the proposed scheme are greater than those of the magnified images using the previous interpolation schemes.

• Korean Journal of Remote Sensing
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• v.38 no.2
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• pp.167-177
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• 2022

In order to obtain satellite image products using the image transmitted to the ground station after capturing the satellite images, many image pre/post-processing steps are involved. During the pre/post-processing, when converting from level 1R images to level 1G images, geometric correction is essential. An interpolation method necessary for geometric correction is inevitably used, and the quality of the level 1G images is determined according to the accuracy of the interpolation method. Also, it is crucial to speed up the interpolation algorithm by the level processor. In this paper, we proposed a lightweight CNN-based interpolation method required for geometric correction when converting from level 1R to level 1G. The proposed method doubles the resolution of satellite images and constructs a deep learning network with a lightweight deep convolutional neural network for fast processing speed. In addition, a feature map fusion method capable of improving the image quality of multispectral (MS) bands using panchromatic (PAN) band information was proposed. The images obtained through the proposed interpolation method improved by about 0.4 dB for the PAN image and about 4.9 dB for the MS image in the quantitative peak signal-to-noise ratio (PSNR) index compared to the existing deep learning-based interpolation methods. In addition, it was confirmed that the time required to acquire an image that is twice the resolution of the 36,500×36,500 input image based on the PAN image size is improved by about 1.6 times compared to the existing deep learning-based interpolation method.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.1
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• pp.26-31
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• 2010

We proposed a new directional edge based interpolation, DEBI, by combining two weighted directional information to reduce blurred edges and annoying artifacts. Four isotropic gradient masks are employed in defining edge directions and they are proven to hold a first order derivative relation with respect to a rotating coordinate. Two minimum gradients among four absolute directional results are shown to be sufficient to describe slant edges efficiently. Compared with widely used bilinear and bicubic interpolation methods, the proposed algorithm results in a noticeable improvement along edge area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.681-683
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• 2017

In the digital information age, image processing is essential for various digital devices such as smart phones, cameras, and TVs. However, degradation occurs in analyzing, recognizing, and processing image data, and salt & pepper noise occurs. Therefore, in this paper, we applied linear interpolation method, newton interpolation method, lagrange interpolation method, and spline interpolation method to the image damaged by salt & pepper noise in order to find more effective interpolation method in salt & pepper noise environment, The methods were compared using the PSNR (peak signal to noise ratio).