• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.235-240
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• 2004

The equipment of industrial robot in manufacturing and assembly lines has rapidly increased. In order to achieve high productivity and flexibility, it becomes very important to develop the visual feedback control system with Off-Line Programming System(OLPS). We can save much efforts and time in adjusting robots to newly defined workcells by using OLPS. A proposed visual calibration scheme is based on position-based visual feedback. The calibration program firstly generates predicted images of objects in an assumed end-effector position. The process to generate predicted images consists of projection to screen-coordinates, visible range test and construction of simple silhouette figures. Then camera images acquired are compared with predicted ones for updating position and orientation data. Computation of error is very simple because the scheme is based on perspective projection which can be also expanded to experimental results. Computation time can be extremely reduced because the proposed method does not require the precise calculation of tree-dimensional object data and image Jacobian.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.213-218
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• 2003

The equipment of industrial robot in manufacturing and assembly lines has rapidly increased. In order to achieve high productivity and flexibility, it becomes very important to develop the visual feedback control system with Off-Line Programming System(OLPS). We can save much efforts and time in adjusting robots to newly defined workcells by using OLPS. A proposed visual calibration scheme is based on position-based visual feedback. The calibration program firstly generates predicted images of objects in an assumed end-effector position. The process to generate predicted images consists of projection to screen-coordinates, visible range test and construction of simple silhouette figures. Then camera images acquired are compared with predicted ones for updating position and orientation data. Computation of error is very simple because the scheme is based on perspective projection which can be also expanded to experimental results. Computation time can be extremely reduced because the proposed method does not require the precise calculation of tree-dimensional object data and image Jacobian.

• 한국정밀공학회지
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• 제21권5호
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• pp.83-83
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• 2004

The analysis of relative pose(position and rotation) between stereo cameras is very important to determine the solution that provides three-dimensional information for an arbitrary moving target with respect to robot-end. In the space of free camera-model, the rotational parameters act on non-linear factors acquiring a kinematical solution. In this paper the general solution of active stereo that gives a three-dimensional pose of moving object is presented. The focus is to achieve a derivation of linear equation between a robot′s end and active stereo cameras. The equation is consistently derived from the vector of quaternion space. The calibration of cameras is also derived in this space. Computer simulation and the results of error-sensitivity demonstrate the successful operation of the solution. The suggested solution can also be applied to the more complex real time tracking and quite general and are applicable in various stereo fields.

• 한국정밀공학회지
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• 제21권5호
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• pp.89-90
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• 2004

The analysis of relative pose(position and rotation) between stereo cameras is very important to determine the solution that provides three-dimensional information for an arbitrary moving target with respect to robot-end. In the space of free camera-model, the rotational parameters act on non-linear factors acquiring a kinematical solution. In this paper the general solution of active stereo that gives a three-dimensional pose of moving object is presented. The focus is to achieve a derivation of linear equation between a robot's end and active stereo cameras. The equation is consistently derived from the vector of quaternion space. The calibration of cameras is also derived in this space. Computer simulation and the results of error-sensitivity demonstrate the successful operation of the solution. The suggested solution can also be applied to the more complex real time tracking and quite general and are applicable in various stereo fields.

• 한국CDE학회논문집
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• 제20권3호
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• pp.263-268
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• 2015

Due to an increased sitting time in work, lumbar disc disease is one of the most frequent diseases in modern days, and this occasionally requires surgery for treatment. Endoscopic disc surgery, one of the common disc surgeries, requires a process of inserting a guide needle to the target disc for which the insertion path is manually planned by drawing lines on the patient's skin while monitoring the fluoroscopic view of the lumbar. Such procedure inevitably exposes both surgeon and patient to the fluoroscopy radiation emitted from the c-arm for a long time. To reduce the radiation exposure time, this study proposes a computer assisted method of calculating the 3D guide needle path by using 2D c-arm images of the disc in 3 different angles. Additionally, a method of the guide robot control based on the 3D needle path was developed by implementing the Hand-eye Calibration method to calculate the transformation matrix between the c-arm and robot base coordinate systems. The proposed system was then tested for its accuracy.

• 대한기계학회논문집
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• 제19권3호
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• pp.670-679
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• 1995

This paper presents the 3-D profile measurement system of live human faces, which was developed specially for 'KUMDORI sculptor robot' of the '93 Taejon Exposition. '93 Taejon EXPO. The basic principle for measurement adopts the slit beam projection which is a method of measuring 3-D surface profiles using geometric optics between the slit beam and the CCD camera. Since the slit beam projection consumes long measuring time, it is unfit to measure the 3-D profiles of living objects as human. Therefore, the projection type slit beam method which consumes short measuring time is newly suggested. And an algorithm to reconstruct the 3-D profile from the deformed images using finite approximated calibration is suggested and practically implemented. The projection type slit beam method was applied to spectators in a period of '93 Taejon EXPO. The measurement results show that the technique is suitable for 3-D face profile measurement on a living body.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.285-286
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• 2006

The essential tasks to operate the welding robot are the acquisition of the position and/or shape of the parent metal. For the seam tracking or the robot automation, many kinds of contact and non-contact sensors are used. Recently, the vision sensor is most popular. In this paper, the development of the system which measures the profile of the welding part is described. The total system will be assembled into a compact module which can be attached to the head of welding robot system. This system uses the line-type structured laser diode and the vision sensor It implemented Direct Linear Transformation (DLT) for the camera calibration as well as radial distortion correction. The three dimensional shape of the parent metal is obtained after simple linear transformation and therefore, the system operates in real time. Some experiments are carried out to evaluate the performance of the developed system.

• 한국지능시스템학회논문지
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• 제8권5호
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• pp.39-44
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• 1998

이동 로봇의 운행을 위해서 이동 로봇의 절대 위치를 결정하는 것이 중요하다. 본 논문에서는 신경회로망을 이용하여 랜드마크의 영상을 통해 이동 로봇의 위치를 결정하는 방법을 제안한다. 픽셀의 불확시한 값, 부정확한 카메라 조정과 렌즈의 왜곡으로 인해 이동 로봇의 위치를 결정에 있어서 위치 오차가 생기게 된다. 이러한 오차를 줄이기 위해서 BPNN(Back Propagation Neural Network)를 사용하는 방법을 제안한다. 기존의 방법과 비교하여 우수성을 보여주기 위해서 실험결과를 보여준다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.225-229
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• 1997

This paper describes the camera calibration based-neural network with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes and inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing. The performance of proposed camera calibration is illustrated by simulation and experiment.

• 센서학회지
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• 제32권6호
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• pp.475-480
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• 2023

When modeling a sensor system mathematically, we assume that the sensor noise is Gaussian and white to simplify the model. If this assumption fails, the performance of the sensor model-based controller or estimator degrades due to incorrect modeling. In practice, non-Gaussian or non-white noise sources often arise in many digital sensor systems. Additionally, the noise parameters of the sensor model are not known in advance without additional noise statistical information. Moreover, disturbances or high nonlinearities often cause unknown sensor modeling errors. To estimate the uncertain noise and model parameters of a sensor system, this paper proposes an iterative batch calibration method using data-driven machine learning. Our simulation results validate the calibration performance of the proposed approach.