• 대한공간정보학회지
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• 제10권2호
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• pp.87-95
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• 2002

실시간 동적(Real Time Kinematic) GPS는 실시간으로 높은 정밀도의 위치결정을 가능케 해준다. 만약 미지정수를 구하기 위하여 정수해를 사용한다면 수 mm의 정확도를 얻을 수 있고, 실 수해를 얻는다면 수십 cm 의 정확도를 얻을수 있다. 본 연구에서는 통일 측점에 대해 기존의 재래식 측량기법(Total Station), 정적(Static) 상대측위 GPS기법과 현장 Calibration에 의한 실시간 동적(Real Time Kinematic) GPS기법에 의해 측량을 수행하여 각 기법별 측정의 정확도 등을 비교 분석하여 현장 Calibration에 의한 실시간 동적 (Real Time Kinematic) GPS기법의 정확도를 분석고자 한다. 국소지역에서 기존의 실시간 동적(Real Time Kinematic) GPS방식을 보완한 현장 Calibration에 의한 실시간 동적(Real Time Kinematic) GPS 측량을 수행한 결과, 미지정수해의 고정해를 얻지 못하는 경우를 제외하고는 모두 6cm 이하의 오차가 나타났고, Control Point의 측점수를 3개와 4개로 변화시켜 실시간 동적(Real Time Kinematic) GPS 측량을 수행한 결과 두 측정치의 차이는 최대 3cm로 나타났다. 최종적으로 국소지역에서도 현장 Calibration에 의한 실시간 동적(Real Time Kinematic) GPS기법이 사용가능함을 알 수 있었다.

• 한국컴퓨터정보학회논문지
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• 제21권11호
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• pp.1-7
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• 2016

In this paper, we proposed real-time relative radiometric calibration processing method for SWIR(Short Wavelength Infra-Red) sensor using 'Hyper-Spectral Imager'. Until now domestic research for Hyper-Spectral Imager has been performing with foreign sensor device. So we have been studying hyper spectral sensor device to meet domestic requirement, especially military purpose. To improve detection & identify capability in 'Hyper-Spectral Imager', it is necessary to expend sensing wavelength from visual and NIR(Near Infra-Red) to SWIR. We aimed to design real-time processor for SWIR sensor which can control the sensor ROIC(Read-Out IC) and process calibrate the image. To build Hyper-Spectral sensor device, we will review the SWIR sensor and its signal processing board. And we will analyze relative radiometric calibration processing method and result. We will explain several SWIR sensors, our target sensor and its control method, steps for acquisition of reference images and processing result.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.643-646
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• 2006

An operational calibration is applied to improve radar rainfall intensity using rainfall obtained from rain gauge. The method is applied under the assumption of the temporal continuity of rainfall, the rainfall intensity from rain gauge is linearly related to that from radar. The method is applied to the cases of typhoon and rain band using the reflectivity of CAPPI at 1.5km obtained from Jindo radar. The CAPPI is obtained by bilinear interpolation. For the two cases, the rainfall intensities obtained by operational calibration are very consistent with the ones by the rain gauges. The present study shows that the correlation between the rainfall intensity by operational calibration and rain gauges is better than the one between the rainfall intensity by M-P relationship and rain gauges. The correlation coefficients between the total rainfall intensity obtained by operational calibration and rain gauges in typhoon and rain band cases are 0.99 and 0.97, respectively. Areal rainfalls are estimated using the field of calibration factor interpolated by Barnes objective analysis. The method applied here shows an improvement in the areal rainfall estimation. For the cases of typhoon and rain band, the correlation between the areal rainfall by operational calibration and rain gauges is better than the one between the area rainfall by M-P relationship and rain gauges. The correlation coefficients between the areal rainfall obtained by operational calibration and rain gauges in typhoon and rain band cases are 0.97 and 0.84, respectively. The present study suggests that the operational calibration is very useful for the real-time estimation of rainfall intensity and areal rainfall.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.269-272
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• 2003

Industry is now seeing a dramatic increase in robot simulation and off-line programming. In order to use off-line programming effectively, the simulated workcell has to be identical to the real workcell. This requires an efficient and accurate method for the workcell calibration. Currently used techniques in the industry, however, are typically time-consuming, expensive and therefore not suitable for in-process application. This is because most of these techniques are based on the so-called “absolute calibration” method. In contrast to absolute method, relative calibration only measures the difference of an interested object relative to a standard reference. Owing to the small measurement range requirement, relative calibration method is very cheap and can achieve very high accuracy. In this paper the relative method is applied to calibrate an entire grinding workcell. Linear gauge is the only measurement device used. This workcell calibration includes tool center point (TCP) calibration and work object frame calibration. Due to the efficiency of the calibration algorithm and the simplicity of the calibration setup, the described calibration procedure can be done in process.

• 한국전기전자재료학회논문지
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• 제25권10호
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• pp.837-843
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• 2012

Compared to conventional pure-tone audiometer(PTA), the computerized one has several advantages such as relatively lower price, better flexibility, and easy operation. In addition, the computerized PTA can be easily extended to support automatic calibration. In this study, the support of automatic calibration in the computerized PTA has been addressed using the Linux realtime spectrum analyzer and network. In terms of accuracy, the new automatic calibration machine was compared to the existing manually operated one. According to the comparison, normal operation and high accuracy were observed within the scope of the international standard.

• 방송공학회논문지
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• 제24권6호
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• pp.965-973
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• 2019

본 논문에서는 Stereo 4K@60fps 360 VR 실시간 영상 획득 시스템을 영상 스트림 획득과 영상 인코딩(encoding), 영상 스티칭(stitching) 모듈로 나누어 설계하였다. 시스템은 6대의 카메라로부터 HDMI Interface를 통해 획득된 6개의 2K@60fps의 영상 스트림을 스티칭을 통하여 실시간으로 Stereo 4K@60fps 360 VR 영상을 획득한다. 영상 획득 단계에서는 멀티 스레드(Multi-Thread)를 이용하여 각 카메라로부터 실시간으로 영상 스트림을 획득하였다. 영상 인코딩 단계에서는 영상 획득과 영상 스티칭 모듈 간의 전송 리소스를 줄이기 위하여 멀티 스레드를 이용한 Raw Frame 메모리 전송과 병렬 인코딩을 하였다. 영상 스티칭 단계에서는 스티칭 Calibration 전처리작업을 통하여 스티칭 실시간성을 확보하였다.

• 대한기계학회논문집
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• 제18권9호
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• pp.2358-2367
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• 1994

This paper presents techniques for evaluation and compensation of total measuring errors in a commercial CMM. The probe errors as well as the machine geometric errors are assessed from probing of the mechanical artefacts such as shpere, step, and rings. For the error compensation, the integrated volumetric error equations are considered, including the probe error adn the machine geometric error. The error compensation is performed on the absolute scale coordinate system, in order to overcome the redundant degree of freedom in the CMM with multi-axis probe. A interface box and corresponding software driver are developed for data intercepting/correction between the machine controller and machine, thus the volumetric errors can be compensated in real time with minimum interference to the operating software and hardware of a commercial CMM. The developed system applied to a practical CMM installed on the shop floor, and demonstrated its performance.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 추계학술대회
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• pp.234-239
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• 2004

This paper describes preliminary results we have obtained in developing a computer vision system based on active IR illumination for real time gaze tracking for interactive graphic display. Unlike most of the existing gaze tracking techniques, which often require assuming a static head to work well and require a cumbersome calibration process fur each person, our gaze tracker can perform robust and accurate gaze estimation without calibration and under rather significant head movement. This is made possible by a new gaze calibration procedure that identifies the mapping from pupil parameters to screen coordinates using the Generalized Regression Neural Networks (GRNN). With GRNN, the mapping does not have to be an analytical function and head movement is explicitly accounted for by the gaze mapping function. Furthermore, the mapping function can generalize to other individuals not used in the training. The effectiveness of our gaze tracker is demonstrated by preliminary experiments that involve gaze-contingent interactive graphic display.

• 한국정밀공학회지
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• 제16권12호
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• pp.87-98
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• 1999

This study is concentrated on the development of real-time estimation model and vision control method as well as the experimental test. The proposed method permits a kind of adaptability not otherwise available in that the relationship between the camera-space location of manipulable visual cues and the vector of manipulator joint coordinates is estimate in real time. This is done based on a estimation model ta\hat generalizes known manipulator kinematics to accommodate unknown relative camera position and orientation as well as uncertainty of manipulator. This vision control method is roboust and reliable, which overcomes the difficulties of the conventional research such as precise calibration of the vision sensor, exact kinematic modeling of the manipulator, and correct knowledge of position and orientation of CCD camera with respect to the manipulator base. Finally, evidence of the ability of real-time vision control method for manipulator's position control is provided by performing the thin-rod placement in space with 2 cues test model which is completed without a prior knowledge of camera or manipulator positions. This feature opens the door to a range of applications of manipulation, including a mobile manipulator with stationary cameras tracking and providing information for control of the manipulator event.

• 전자공학회논문지
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• 제51권2호
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• pp.102-113
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• 2014

본 논문은 두 대의 카메라로 찍은 영상을 이용하여 사물의 3D 정보를 계산하는 스테레오 매칭(Stereo Matching) 기법의 전처리 과정에 관한 연구이다. 본 논문에서는 카메라 내부의 왜곡 및 두 카메라간의 정렬 문제로 인해 생긴 영상의 수직시차(vertical parallax)를 제거하기 위한 실시간 편위교정(Rectification) 하드웨어 설계 구조를 제안한다. 이를 위한 사전 단계로 J.Y Bouguet이 설계한 Matlab 툴박스를 이용해 영상의 보정 매개변수(calibration parameter)를 구한 후 Heikkila 와 Silven의 알고리즘을 기반으로 하여 편위교정 하드웨어를 설계하였다. 이때 결과 이미지의 정밀도를 높이기 위하여 Xilinx의 Core 생성기를 이용해 부동소수점 연산기를 생성하여 사용하였으며, 이를 통하여 룩업 테이블(Look-Up Table) 등을 사용하여 설계된 타 편위교정 하드웨어에 비해 높은 정밀도를 가지면서도 실시간으로 작동하는 편위교정 하드웨어를 설계할 수 있음을 확인하였다.