• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.578-583
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• 2014

Optical pick-up is a core component for data read/write operations in optical disc drives, and an optical pick-up performance evaluator is an instrument used to analyze the overall performance of an optical pick-up. Due to inevitable errors in an analog measurement circuit, resultant evaluation data is not guaranteed to be accurate. In this paper, a calibration method for an optical pick-up performance evaluator is proposed to ensure evaluation accuracy. Measured data is corrected by a 1st order correction function, and a calibration process based on least-square method is utilized to obtain correction coefficients of the correction function. The proposed calibration method is applied to experiments, and enhanced accuracy is presented with resultant evaluation data.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.9
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• pp.922-931
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• 2011

An efficient calibration algorithm for mobile robot localization using infrared range finder is proposed. A calibration is important to guarantee the performance of other algorithms which use sensor data because it is pre-process. We experimentally found that the infrared range finder PBS-03JN has error characteristics depending on both distance and scan angle. After obtaining 2-D grid error characteristic data on distance and scan angle, we proposed a simple and efficient calibration algorithm with a 2-D piecewise linear function set. The performance of our proposed calibration algorithm is verified by experiments and simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.1005-1009
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• 2010

This paper presents a digitally-controlled filter calibration technique for biquad RC filter using self oscillation. The biquad RC filter is converted to a fully-differential ring oscillator by changing its resistor connections, where the oscillation frequency reflects the cut-off frequency. The proposed calibration circuit measures the oscillation frequency by counting with a fixed higher-frequency clock and then tunes it to a desired frequency with a digital frequency-locked loop including a PI controller. Because the proposed circuit directly measures the cut-off frequency of the filter itself and calibrates it with the small area digital circuits, the area and the power consumption are much small compared with conventional works. When it is implemented in a 65nm CMOS process, the calibration circuit except the filter consumes the area of 80um X 50um and power consumption is 443uA at 1.2 V supply voltage.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.577-578
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• 2008

This paper proposes new analog ZQ calibration scheme. Proposed analog ZQ calibration scheme is for minimizing the reflection which degrade the signal integrity. And this scheme is for minimizing CIO capacitance. It is simulated under 1.5v supply voltage and samsung 0.18um process. Power consumption of proposed analog ZQ calibration circuit was improved by 32%. Under all skew, temperature from $30^{\circ}C$ to $90^{\circ}C$ and Monte carlo simulation, quantization error of RZQ(=$240{\Omega}$) is less han 1.07%.

• Ocean Systems Engineering
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• v.1 no.3
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• pp.195-205
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• 2011

A method for calibrating a laser profiling system for seafloor micro-topography measurements is described. The system consists of a digital camera and an arrangement of six red lasers that are mounted as a unit on a remotely operated vehicle (ROV). The lasers project as parallel planes onto the seafloor, creating profiles of the local topography that are interpreted from the digital camera image. The goal of the calibration was to determine the plane equations for the six lasers relative to the camera. This was accomplished in two stages. First, distortions in the digital image were corrected using an interpolation method based on a virtual pinhole camera model. Then, the laser planes were determined according to their intersections with a calibration target. The position and orientation of the target were obtained by a registration process. The selection of the target shape and size was found to be critical to a successful calibration at sea, due to the limitations in the manoeuvrability of the ROV.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.230-238
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• 1996

In this paper, digital corrction and calibration circuit for a high-resolution CMOS pipelined A/D converter are proposed. The circuits were actually applied to a 12 -bit 4-stage pipelined A/D converter which was implemented in a 0.8${\mu}$m p-well CMOS process. The proposed digital correction logic is based on optimum multiplexer and two nonoverlapping clock phases resulting in a small die area snd a modular pipelined architecture. The propsoed digital calibration logic which consists of calibration control logic, error averaging logic, and memory can effectively perform self-calibration with little modifying analog functional bolcks of a conventional pipelined A/D conveter.

• Journal of Sensor Science and Technology
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• v.23 no.1
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• pp.66-71
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• 2014

Vision is the most important sensing capability for both men and sensory smart machines, such as intelligent robots. Sensed real 3D world and its 2D camera image can be related mathematically by a process called camera calibration. In this paper, we present a novel linear solution of camera calibration. Unlike most existing linear calibration methods, the proposed technique of this paper can identify camera parameters explicitly. Through the step-by-step procedure of the proposed method, the real physical elements of the perspective projection transformation matrix between 3D points and the corresponding 2D image points can be identified. This explicit solution will be useful for many practical 3D sensing applications including robotics. We verified the proposed method by using various cameras of different conditions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.131-136
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• 1999

This paper proposes the robot inverse calibration method using a neural networks. A highorder networks called Pi-Sigma networks has been used. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position, orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness, the SCARA type direct drive robot(4-DOF) and anthropomorphic robot(6-DOF) are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from $\pm$2$^{\circ}$to $\pm$ 0.1$^{\circ}$.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.131-142
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• 1996

Most industrial robots cannot be off-line programmed to carry out a task accurately, unless their kinematic model is suitably corrected through a calibration procedure. However, normal calibration is an expensive and time-consumming precedure due to the highly accurate measurement equipment required and due to the significant amount of data that must be collected. This paper presents a simple and economic procedure to improve the efficiency of robot calibration especially for arc welding application. To simplify the measurement process, an automotic data measurement algorithm as well as a simple measurement device are developed. Also, a calibration algorithm which can automatically identify the independent model parameters to be estimated is presented. To demonstrated the simplicity and the effectiveness of the procedure, experimental studies and computer simulations are performed and their results are discussed.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.9
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• pp.819-822
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• 2012

This paper describes an on-line magnetic distortion calibration procedure for a magnetometer. The horizontal magnetic field is calculated through the earth magnetic field sensed by 3-axes magnetometer. The ellipse equation is derived from a set of horizontal magnetic field data using least square method and calibration parameters are determined. The calibration process is performed iteratively until parameters are not renewed, and experimental results show the effectiveness of the devised method.