새로운 거리 가중치와 지역적 패턴을 고려한 적응적 선형보간법

김태양,전영균,정제창,Kim, Tae-Yang,Jeon, Yeong-Gyun,Jeong, Je-Chang 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.12C

영상 보간은 영상 처리 분야에서 전통적으로 많이 연구되어 왔고 널리 사용되고 있다. 그에 따라 다양한 보간 능력과 계산 복잡도를 갖는 보간법들이 많이 시도되고 있다. 이 논문에서는 기존의 선형 보간법을 위한 새로운 거리 가중치 개념과 보간되는 값의 상하, 좌우 지역적 패턴을 고려하여 반영하는 적응적 선형 보간법(New Adaptive Linear Interpolation : NAL Interpolation)을 제안한다. 새로운 거리 가중치는 기존의 거리에 선형적으로 비례하는 가중치의 개념에서 벗어나 가까운 화소에 더욱 더 영향을 많이 받는 특성을 이용하여 거리 가중치를 2차, 3차 다항식으로 개선한 것이다. 또한 NAL 보간법은 보간되는 화소의 상하, 좌우 패턴을 고려하는 선형 보간법으로 MF(magnification factor)의 변화에 따라 보다 선명한 이미지를 쉽게 얻기 위해서 보간하기 전 MF에 따라 패턴을 반영하는 정도를 결정하는 패턴 가중치를 이용한다. 실험 결과에서 제안된 보간법은 계산 복잡도 면에서 기존의 bicubic 보간법 보다 훨씬 간단할 뿐만 아니라 더 좋은 PSNR(peak signal-to-noise ratio)를 갖고 보다 선명한 화질의 영상으로 보간하였다. Image interpolation has been widely used and studied in the various fields of image processing. There are many approaches of varying complexity and robustness. In this paper, a new distance weight is proposed for the conventional linear interpolation. In comparison with the conventional linear weight, the new distance weight uses a quadratic or cubic polynomial equation to reflect that the interpolated value should be influenced more by the value of closer pixels in an input image. In this paper, the new adaptive linear (NAL) interpolation, which considers patterns near the interpolated value, is also proposed. This algorithm requires a pattern weight, which is used to determine the ratio of reflection on local patterns, to obtain an interpolated image that exhibits better quality at various magnification factors (MF). In the computer simulation, not only did the NAL interpolation exhibit much lower computational complexity than conventional bicubic interpolation, it also improved peak signal-to-noise ratios (PSNR).

이미지 보간기법의 성능 개선을 위한 비국부평균 기반의 후처리 기법

김동형 (사)디지털산업정보학회 2020 디지털산업정보학회논문지 Vol.16 No.3

Image interpolation, a technology that converts low resolution images into high resolution images, has been widely used in various image processing fields such as CCTV, web-cam, and medical imaging. This technique is based on the fact that the statistical distributions of the white Gaussian noise and the difference between the interpolated image and the original image is similar to each other. The proposed algorithm is composed of three steps. In first, the interpolated image is derived by random image interpolation. In second, we derive weighting functions that are used to apply non-local mean filtering. In the final step, the prediction error is corrected by performing non-local mean filtering by applying the selected weighting function. It can be considered as a post-processing algorithm to further reduce the prediction error after applying an arbitrary image interpolation algorithm. Simulation results show that the proposed method yields reasonable performance.

서울 지역 지상 NO₂ 농도 공간 분포 분석을 위한 회귀 모델 및 기계학습 기법 비교

강은진 ( Eunjin Kang ),유철희 ( Cheolhee Yoo ),신예지 ( Yeji Shin ),조동진 ( Dongjin Cho ),임정호 ( Jungho Im ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.6

대기 중 이산화질소(NO₂)는 주로 인위적인 배출요인으로 발생하며 화학 반응을 통해 이차오염 물질 및 오존 형성에 매개 역할을 하는 인체 건강에 악영향을 미치는 물질이다. 우리나라는 지상 관측소에 의한 실시간 NO₂ 모니터링을 수행하고 있지만, 이는 점 기반의 관측 값으로써 미관측 지역의 공간 분포 분석이 어렵다는 한계점을 지닌다. 본 연구에서는 선형 회귀 기반 모델인 다중 선형 회귀와 회귀 크리깅, 기계학습 알고리즘인 Random Forest (RF), Support Vector Regression (SVR)을 적용한 공간 내삽 모델링을 통해 서울 지역의 지상 NO₂ 농도 지도를 제작하였고, 일별 Leave-One-Out Cross Validation (LOOCV) 교차 검증을 시행하였다. 2020년 연구 기간 내 일별 LOOCV에서 MLR, RK, SVR 모델의 일별 평균 Index of agreement (IOA)는 약 0.57로 유사한 성능을 보였으며, RF (0.50)보다 높은 성능이 확인되었다. RK의 일별 평균 nRMSE는 0.9483%으로MLR (0.9501%)보다 상대적으로 낮은 오차를 나타냈다. MLR과 RK, RF 모델의 계절별 공간 분포는 비슷한 양상을 보였으며, RF는 다른 모델에 비해 좁은 NO₂ 농도 범위가 확인되었다. 본 연구에서 제안된 선형 회귀 기반 공간 내삽은 지상 NO₂ 뿐 아니라 다른 대기 오염 물질의 도시 지역 공간 내삽을 위해 활용 가능성이 높을 것으로 기대된다. Atmospheric nitrogen dioxide (NO₂) is mainly caused by anthropogenic emissions. It contributes to the formation of secondary pollutants and ozone through chemical reactions, and adversely affects human health. Although ground stations to monitor NO₂ concentrations in real time are operated in Korea, they have a limitation that it is difficult to analyze the spatial distribution of NO₂ concentrations, especially over the areas with no stations. Therefore, this study conducted a comparative experiment of spatial interpolation of NO₂ concentrations based on two linear-regression methods (i.e., multi linear regression (MLR), and regression kriging (RK)), and two machine learning approaches (i.e., random forest (RF), and support vector regression (SVR)) for the year of 2020. Four approaches were compared using leave-one-out-cross validation (LOOCV). The daily LOOCV results showed that MLR, RK, and SVR produced the average daily index of agreement (IOA) of 0.57, which was higher than that of RF (0.50). The average daily normalized root mean square error of RK was 0.9483%, which was slightly lower than those of the other models. MLR, RK and SVR showed similar seasonal distribution patterns, and the dynamic range of the resultant NO₂ concentrations from these three models was similar while that from RF was relatively small. The multivariate linear regression approaches are expected to be a promising method for spatial interpolation of ground-level NO₂ concentrations and other parameters in urban areas.

쿼터니언을 이용한 6축 로봇 방위 보간법에 관한 연구

안진수(Jin-Su Ahn),정원지(Won-Jee Chung) 한국생산제조학회 2010 한국생산제조시스템학회 학술발표대회 논문집 Vol.2010 No.10

This paper presents the study on 6-Axis Articulated Robot Using using a quaternion Interpolation. In this paper, we propose a control algorithm between given two orientations of 6-Axis Articulated robot by using a quaternion with spherical linear interpolation. In order to study the Quaternion Interpolation, We created Inverse kinematics program and Interpolation program using LabVIEW<SUP>®</SUP>. The rotation angle of each axis were calculated using the euler interpolation program and quaternion Interpolation program. The proposed control algorithm is shown to be effective in terms of motor angles and torques when compared to a conventional Euler angle interpolation, by using both LabView<SUP>®</SUP> and RecurDyn<SUP>®</SUP>.

쿼터니언을 이용한 6축 로봇 방위 보간법에 관한 연구

안진수(Jin-Su Ahn),정원지(Won-Jee Chung) 한국생산제조학회 2010 한국공작기계학회 추계학술대회논문집 Vol.2010 No.-

This paper presents the study on 6-Axis Articulated Robot Using using a quaternion Interpolation. In this paper, we propose a control algorithm between given two orientations of 6-Axis Articulated robot by using a quaternion with spherical linear interpolation. In order to study the Quaternion Interpolation, We created Inverse kinematics program and Interpolation program using LabVIEW<SUP>®</SUP>. The rotation angle of each axis were calculated using the euler interpolation program and quaternion Interpolation program. The proposed control algorithm is shown to be effective in terms of motor angles and torques when compared to a conventional Euler angle interpolation, by using both LabView<SUP>®</SUP> and RecurDyn<SUP>®</SUP>.

쿼터니언을 이용한 6축 로봇 방위 보간법에 관한 연구

안진수(Jin-Su Ahn),정원지(Won-Jee Chung) 한국생산제조학회 2011 한국생산제조학회지 Vol.20 No.6

This paper presents the study on orientations interpolation of 6-axis articulated robot using quaternion. In this paper, we propose a control algorithm between given two orientations of 6-axis articulated robot by using a quaternion with spherical linear interpolation. In order to study the quaternion interpolation, We created Inverse kinematics program and Interpolation program using LabVIEW<SUP>®</SUP>. The rotation angle of each axis were calculated using both euler orientations interpolation program and quaternion orientations interpolation program. The proposed control algorithm is shown to be effective in terms of motor angles and torques when compared to a conventional Euler angle interpolation, by using both LabVIEW<SUP>®</SUP> and RecurDyn<SUP>®</SUP>.

Comparison of CZCS and SeaWiFS Pigments for Merging the Higher Level Ocean Color Data

Jeong, Jong-Chul,Yoo, Shin-Jae The Korean Society of Remote Sensing 2002 大韓遠隔探査學會誌 Vol.18 No.5

Many ocean color sensors are being operated at present and will be continued to operatein the coming years. However, these ocean color sensors have different spectral bands locations and higher level product algorithms. Thus the continuity of ocean color data from the satellite with different missions will be important for monitoring of oceanographic variation with long term research. In this study, CZCS band and algorithm are compared with OCTS and SeaWiFS algorithm for estimating chlorophyll. Missing bands of OCTS and CZCS for chlorophyll algorithm are estimated by linear-interpolation using SeaWiFS data. We were able to evaluate the effectiveness of the correction methods using linear interpolation method. Surprisingly, linear interpolation gave a better result than those of other bands.

Communication : Comparison of CZCS and SeaWiFS Pigments for Merging the Higher Level Ocean Color Data

Jong Chul Jeong,Sin Jae Yoo 大韓遠隔探査學會 2002 大韓遠隔探査學會誌 Vol.18 No.5

Many ocean color sensors are being operated at present and will be continued to operate in the coming years. However, these ocean color sensors have different spectral bands locations and higher level product algorithms. Thus the continuity of ocean color data from the satellite with different missions will be important for monitoring of oceanographic variation with long term research. In this study, CZCS band and algorithm are compared with OCTS and SeaWiFS algorithm for estimating chlorophyll. Missing bands of OCTS and CZCS for chlorophyll algorithm are estimated by linear-interpolation using SeaWiFS data. We were able to evaluate the effectiveness of the correction methods using linear interpolation method. Surprisingly, linear interpolation gave a better result than those of other bands.

Efficient Estimation of Population Mean Using Centered Modified Systematic Sampling and Interpolation

Kim, Hyuk-Joo,Choi, Byoung-Chul The Korean Statistical Society 2002 Communications for statistical applications and me Vol.9 No.1

A method is proposed for efficiently estimating the mean of a population which has a linear trend. The proposed estimator is based on the centered modified systematic sampling method and the concept of interpolation. Using the expected mean square error criterion, it is shown that the proposed method is more efficient than conventional methods in most real cases.

A Twofold-interpolation-based Path Planning Algorithm and Its Path Following Based on Improved Virtual Vehicle Method

Zhiwei Liang,Songhao Zhu,Fang Fang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.1

In this paper, an interpolation-based path planning algorithm is employed for generating smooth paths on uniform resolution grid-maps. First, it starts at the goal node and propagates through four neighboring nodes, assigning monotonically increasing values to nodes using FMM (Fast Marching Method) interpolation. Consequently, we obtain a goal-propagation map that is zero-cost at the goal node and monotonically increasing along the wavefront propagation from the goal node. Subse-quently, it begins from the robot’s position and uses a linear interpolation approach to generate near-optimal paths. After obtaining the planned path, an improved path following algorithm based on an improved virtual vehicle method is employed to follow the path considering the robot’s dynamic and kinematic constraints. The experimental results demonstrate the performance of our approach.