• Journal of Biomedical Engineering Research
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• v.5 no.2
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• pp.111-120
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• 1984

A new restoration method of chest X-ray image (dual project filter) was proposed to improve SNR (signal to noise ratio) characteristics. In this method, a priori information of system and anatomical structure and statistics of projected object are used in the design of filter. Dual projection filter varies its parameters, adapting to the local regions of chest(lungregion, mediasternum, subdiaphragm) and the structure of chest (bone, tissue, blood vessel, bronchia). The performance of Dual Projection Filter was 0.1-0.2dB better than Dual Sensor Wiener Filter, which was used for initial estimate of Dual Porjection Filter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.133-135
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• 2004

신경 회로망에서 연상 메모리(Associative Memory)는 주어진 자료에 대해 정보를 저장하고 복원하는 알고리즘이다. 본 논문에서는 학습된 영상의 정확한 분류와 왜곡된 영상의 복원 및 분류를 위해 기존의 퍼지 연상 메모리 알고리즘을 개선하였다. 기존의 퍼지 연상 메모리는 학습 데이터와 학습 원본과 같은 입력에 대해 우수한 복원 성능을 보이나 학습 데이터의 수가 증가할수록 그리고 왜곡된 입력에 대해 정확히 출력할 수 없고 복원 성능도 저하된다. 따라서 본 논문에서는 기존의 퍼지 연상 메모리 알고리즘을 개선하여 왜곡된 입력에 대해서도 원본 학습 데이터를 정확히 출력하고 복원하는 개선된 퍼지 연상 메모리 알고리즘을 제안하였다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.219-222
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• 2002

본 논문에서는 잘못된 인쇄로 인한 문서상의 잡영이 생기거나 문자 훼손이 있는 문서영상을 복원 하고자 한다. 제안하는 방법은 문서영상을 스캐너로 읽어들여 잡영을 제거 한 뒤 훼손된 숫자 영상에 대해서 프로젝션을 이용하여 숫자 열을 낱낱의 숫자로 분할한다. 각각의 숫자에 대해서 크기가 일정하도록 정규화를 시킨 다음, Backpropagation을 이용하여 훼손된 숫자를 학습하였다. 학습시킨 다음 원 영상과 훼손된 영상을 각 픽셀단위로 비교하여 4-방향 마스크를 이용하여 원래의 숫자 영상으로 복원하도록 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.562-564
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• 2002

최근 커널의 특정부분을 사용자 임의로 수정하여 시스템을 공격하는 여러 가지 기법들, 즉 커널 백도어가 늘어나고 있다. 이 커널 백도어의 문제점은 커널 자체를 수정하기 때문에 탐지 및 복구가 힘들다는 것이다. 이에 대응하여 커널 백도어를 탐지하는 대부분의 방법이 특정 주소를 검사하여 이루어지는데 이는 확실한 탐지에는 한계가 있다. 설사 탐지는 가능하다 하더라도 복구는 거의 불가능한 것이 현실이다. 이에 본 논문에서는 커널이 기동될 때 사용되는 순수한 부트 이미지와 커널에서 실행중인 이미지를 비교하여 커널의 무결성을 검사, 복구하는 시스템을 제안한다.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.5
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• pp.225-232
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• 2021

Deraining is one of the image restoration tasks and should consider a tradeoff between local details and broad contextual information while recovering images. Current studies adopt an attention mechanism which has been actively researched in natural language processing to deal with both global and local features. This paper classifies existing deraining methods and provides comparative analysis and performance comparison by using several datasets in terms of generalization.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.319-321
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• 2020

스테레오 이미지는 카메라 두 대를 사용하여 찍은 미묘하게 다른 두 사진을 의미한다. 이 차이는 우리가 두 눈의 차이로 대상과의 거리를 계산하는 것처럼 이미지의 깊이를 예측할 수 있기에 요즘 주목받고 있는 자율주행 자동차나 로봇 비전에 이 기술이 사용된다. 심지어는 스마트폰 또한, 듀얼 카메라라는 이름으로 우리 일상생활에 쉽게 접할 수 있다. 이러한 상황에서 본 논문에서는 두 대의 카메라에서 찍힌 스테레오 이미지에서 손상된 한쪽의 이미지를 복원하는 기술문제에 대해 다루고자 한다.

• Journal of Ecology and Environment
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• v.41 no.4
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• pp.114-119
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• 2017

This study tried to analyze error range and resolution of drone images using a rotary wing by comparing them with field measurement results and to analyze stands patterns in actual vegetation map preparation by comparing drone images with aerial images provided by National Geographic Information Institute of Korea. A total of 11 ground control points (GCPs) were selected in the area, and coordinates of the points were identified. In the analysis of aerial images taken by a drone, error per pixel was analyzed to be 0.284 cm. Also, digital elevation model (DEM), digital surface model (DSM), and orthomosaic image were abstracted. When drone images were comparatively analyzed with coordinates of ground control points (GCPs), root mean square error (RMSE) was analyzed as 2.36, 1.37, and 5.15 m in the direction of X, Y, and Z. Because of this error, there were some differences in locations between images edited after field measurement and images edited without field measurement. Also, drone images taken in the stream and the forest and 51 and 25 cm resolution aerial images provided by the National Geographic Information Institute of Korea were compared to identify stands patterns. To have a standard to classify polygons according to each aerial image, image analysis software (eCognition) was used. As a result, it was analyzed that drone images made more precise polygons than 51 and 25 cm resolution images provided by the National Geographic Information Institute of Korea. Therefore, if we utilize drones appropriately according to characteristics of subject, we can have advantages in vegetation change survey and general monitoring survey as it can acquire detailed information and can take images continuously.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1096-1101
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• 2004

The 3-D shape use to effect of movie, animation, industrial design, medical treatment service, education, engineering etc.... But it's not easy to make 3-D shape from the information of 2-D image. There are two methods in restoring 3-D video image through 2-D image; First the method of using a laser; Secondly the method of acquiring 3-D image through stereo vision. Instead of doing two methods with many difficulties, I figure out the method of simple 3-D image in this research paper. We present here a simple and efficient method, called direct calibration, which doesn't require any equations at all. The direct calibration procedure builds a lookup table(LUT) linking image and 3-D coordinates by a real 3-D triangulation system. The LUT is built by measuring the image coordinates of a grid of known 3-D points, and recording both image and world coordinates for each point; the depth values of all other visible points are obtained by interpolation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.5 s.311
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• pp.30-36
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• 2006

In this paper, a new type of written image segmentation based on relative comparison of region areas is proposed. The original image is composed of two distinctive regions; information and background. Compared with this binary original image, the observed one is the gray scale which is represented with complex regions with speckles and noise due to degradation or contamination. For applying threshold or statistical approach, there occurs the region-deformation problem in the process of binarization. At first step, the efficient iterated conditional mode (ICM) which takes the lozenge type block is used for regions formation into the binary image. Secondly the information region is estimated through selecting action and restored its primary state. Not only decision of the attachment to a region but also the calculation of the magnitude of its area are carried on at each current pixel iteratively. All region areas are sorted into a set and selected through the decision parameter which is obtained statistically. Our experiments show that these approaches are effective on ink-rubbed copy image (拓本 'Takbon') and efficient at shape restoration. Experiments on gray scale image show promising shape extraction results, comparing with the threshold-segmentation and conventional ICM method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.455-458
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• 2008

Former times Information Technology generally has only depended on text or sound, while nowadays information is being moved through a variety of image media. Cell phone, TV and computer have been major elements of modem society as mediators using image signal. Therefore, image signal processing also has been treated importantly and done actively. The processing has been developed in many fields of digital image processing technologies as image data compression, recognition, restoration, etc. Noises are inevitably generated by using the signals during the processing, and typical types of the noise are Impulse(salt & pepper) and AWGN(Addiction White Gaussian Noise). To reduce the noise, various kinds of filters have been developed, and according to each noise, it is being used different filter each. However, the noise is not generated by one signal but by a complex. In this paper, I suggested an image filter to remove the complex noise, and compared with existing filters' methods for verification.