신뢰확산 알고리듬을 이용한 선 그룹화 기반 스테레오 정합

김봉겸,임재권,Kim Bong-Gyum,Eem Jae-Kwon 대한전자공학회 2005 電子工學會論文誌-SP (Signal processing) Vol.42 No.3

변이 영상을 마코브 랜덤필드(MRF)로 모델링한 마코브 네트워크에서 신뢰확산 알고리듬은 각 화소에 대응되는 노드들 사이에 메시지를 전달하는 방식으로 이루어진다. 최초 메시지는 알고리듬의 반복을 통해 특정한 값으로 수렴하게 되며, 수렴된 값을 얻기 위해서는 많은 알고리듬의 반복이 필요하다. 본 논문에서는 알고리듬의 반복을 줄이기 위해 영상내 물체들을 선들의 조합 구성으로 보고 각각의 선들은 같은 메시지를 갖는 노드들의 집합으로 간주하여 기존의 신뢰확산 알고리듬을 단순화하였다. In the Markov network which models disparity map with the Markov Random Fields(MRF), the belief propagation algorithm is operated by message passing between nodes corresponding to each pixel. The initial message value is converged by iterations of the algorithm and the algorithm requires many iterations to get converged messages. In this paper, we simplify the algorithm by regarding the objects in the disparity map as combinations of lines with same message valued nodes to reduce iterations of the algorithm.

디지털 TV의 출력 칼라변환 행렬에 의한 기준색 조정

성영모(Young-Mo Sung),임재권(Jae-Kwon Eem) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.1

In this paper, we propose a method of adjusting the output CSC(Color Space Conversion) 3×3 matrix located in DTV chipset to map the color gamut of primary colors with its HDTV broadcast standard-ITU_BT_709 and we present the regarding experimental results produced. A computer controllable automatic primary color tuning system was designed and implemented. Using the system, we measured u’ and v’ values of reproduced colors on DTV panel which depend on the values of each element of the CSC matrix. Based on the observations of data, we represent the functional relationships as a set of linear regression equations which are employed in automatic primary color tuning algorithm. The proposed approach has been tested on DTVs and compared the color differences. As the iterations continue the color differences are refined towards its goal values. Through the tuning process we imposed the constraint that sum of each row in the CSC matrix to be 1 to maintain reference white point on the spot of specified color temperature.

계층적 푸리에 상관을 이용한 스테레오 매칭

이승목(Seung-Mok Lee),임재권(Jae-Kwon Eem) 한국정보기술학회 2015 한국정보기술학회논문지 Vol.13 No.12

In this paper, we propose a stereo matching algorithm using hierarchical Fourier correlations for stereo correspondence problem. Proposed algorithm shows a range-reduced DFT of divided real-valued data sequence, a correlation of these DFTs, and a block correlation image. For a dense stereo matching, the correlation volume space can be calculated using block correlations and matching costs of block matching together. The disparity map is also obtained by using WTA(winner-take-all) algorithm and SMF(selective mode filter). Performance of the proposed method is evaluated by RMS(root mean squared) error and BP(percentage of bad matching pixels) based on GT(ground truth) data. Experiments are conducted on several stereo images and show a kind of complementary relation between matching costs of block matching and the Fourier correlations. The proposed method could be implemented for real-time stereo system using FFT.

계층적 푸리에 상관과 적응적 영역 가중치를 이용한 스테레오 매칭

이승목(Seung-Mok Lee),임재권(Jae-Kwon Eem) 한국정보기술학회 2016 한국정보기술학회논문지 Vol.14 No.4

For obtaining a dense disparity map of stereo matching, we propose an algorithm using hierarchical Fourier correlations and ASW(adaptive support-weight). The hierarchical Fourier correlations are obtained using cross-correlation of range-reduced DFTs(discrete Fourier transforms) in hierarchical layers. The ASW technique is used as a robust local matching method for computing matching costs with intensities of the stereo images. Evaluations are performed on the disparity map obtained using the cost volume and WTA(winner-take-all) algorithm. The performances are calculated dependent on window size of the ASW method. Experiments for performance evaluation are also conducted on the disparity refinement using a small size median filter.

디지털 TV의 영상신호 특성 측정시스템 구현

성영모(Young-Mo Sung),임재권(Jae-Kwon Eem) 한국정보기술학회 2010 한국정보기술학회논문지 Vol.8 No.8

Image signal is finally transmitted to the digital display panel through the various image processing and displayed on the screen. In this paper, we design and implement an image signal measurement system for measuring image signal characteristics from the image board system that receives and processes input image signal(LVDS). To measure the characteristics of the panel input image signal, we suggest a method for measuring the sharpness after displaying a specific bar pattern to the TV set under test and the contrast ratio in patterns with more changes than single colors. In addition, this study implemented the system to measure image signal characteristics and applied the system to measurement of image signal characteristics of LCD TV, and PDP TV set. This system can measure comprehensive effects of image processing algorithms used in image boards of the digital TV.

RANSAC 방법을 이용한 패널 합착 영상의 갭 측정 검사 방법

이승목(Seung-Mok Lee),임재권(Jae-Kwon Eem) 한국정보기술학회 2020 한국정보기술학회논문지 Vol.18 No.8

This paper proposes a method of inspecting the gap between the panel edge and the inner edge of the backlight module to check the bonding state after panel bonding process. When the panel and the backlight module are bonded and then an image is taken on the bonded edge, image noise is generated by the step difference in the panel edge, edge contamination, or material characteristics and deformation of the backlight module. Due to this noise, it is usually measured using a 3D laser sensor device rather than using an image processing. The proposed algorithm detected edge lines through the RANSAC(RANdom SAmple Consensus) method using standard deviation, and measured gap distance between edge lines. The performance of the proposed algorithm was evaluated by comparing with the RANSAC algorithm for various gap images.

크기의 차이가 큰 영상 간의 순환 교차상관의 연산방법

이승목(Seung-Mok Lee),임재권(Jae-Kwon Eem) 한국정보기술학회 2013 한국정보기술학회논문지 Vol.11 No.10

In this paper, we propose a computational method of circular cross correlation for images with large difference of size. In case of expressing a 2D representation for each pixel value of the image with extending Fourier series, the 2D representation of zero-padded image have a positive sign tendency because the image consists of positive pixel values. Using this tendency, proposed method presents a fast computation for circular cross correlation. Recently, larger size images are handled by the demands for high quality images and fast algorithms are required necessarily for these images. And many researchers studied in the MARS (multimedia archive retrieval system) and video-on-demand. Proposed method could be used to find matched images among those images. Experiments are carried out for various images and we show the computational results and its corresponding differences.

계층적 푸리에 상관과 신뢰 전파를 이용한 스테레오 매칭

이승목(Seung-Mok Lee),임재권(Jae-Kwon Eem) 한국정보기술학회 2016 한국정보기술학회논문지 Vol.14 No.3

For the dense stereo correspondence problem, we propose an algorithm using hierarchical Fourier correlations as a complementary parameter. Proposed hierarchical Fourier correlations are calculated by using range-reduced DFTs(discrete Fourier transforms) and these normalized cross-correlations. In MRF(Markov random field) model as energy-minimization problem, the normalized correlation is added to a part of the term of data cost in energy function. Then a better disparity map is obtained using energy minimization by BP(belief propagation). The performances are evaluated by RMS(root mean squared) error and percentage of bad matching pixels based on given GT(ground truth) data. Our experiments is implemented for stereo images and shows advantages of newly added term with the number of iterations. For real-time stereo systems, the proposed method can be implemented using FFT algorithm.

DTV 디스플레이 장치의 칼라측정 시스템 구현

성영모(Young-Mo Sung),임재권(Jae-Kwon Eem) 한국정보기술학회 2007 한국정보기술학회논문지 Vol.5 No.4

Recently, according to the trend for larger screen size and full HD of digital display panels in FPDs, the main display panel and DTV set manufactures are concerned about digital display device's color characteristics and are studying the image color enhancement by these color characteristics. Fundamentally DTV's color characteristics are determined from the type and characteristics of the digital display panel, but also image processing chips for the panel and image processing techniques effect the digital display's overall color appearance. In this paper, we proposed to analyze the panel input color signal(LVDS) to eliminate color variations of the circuit boards. The hardware is implemented and verified successfully using FPGAs. Typically the color performance of DTV systems were measured only on the display screen, but with this experiment we measured color from the panel input signal as well as the screen color and compared the two. The proposed system can respectively and automatically measure both, so that with our proposed system it is possible to compare individual panels. This system can play a large role in evaluating the panel color performance and developing future panels.

입력 영상의 서브블록들 사이의 상관계수에 기반한 고속 프랙탈 부호화

배수정(Su Jung Bae),임재권(Jae Kwon Eem) 대한전자공학회 1998 대한전자공학회 학술대회 Vol.1998 No.6