• Current Optics and Photonics
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• 제8권3호
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• pp.307-312
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• 2024

Measuring the three-dimensional (3D) spatial light intensity distribution of an autostereoscopic multiview 3D display at the user position is time-consuming, as luminance has to be measured at different positions around the user position. This study investigates a method to quickly estimate the 3D distribution at the user position. For this purpose, a measurement setup using a white semitransparent diffusing screen or a two-dimensional (2D) spatial sensor was devised to measure the 2D light intensity distribution at the user position. Furthermore, the 3D spatial light intensity distribution at the user position was estimated from these 2D distributions at different viewing distances. From the estimated 3D distribution, the characteristics of autostereoscopic 3D display performance can be derived and the candidate positions for further accurate measurement can be quickly determined.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.964-968
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• 2007

The measurement of floor impact sound have been standardized in KS 2810-1 and 2. The height of receiving microphones position is specified in the standard as 1.2m which is almost half height of apartment rooms as a listening position. In this study, receiving positions are investigated by measuring the distribution of sound pressure levels at 792 receiving microphone positions in the standard testing building. Standard impact sources, tapping machine and impact ball, are driven on the center position in the source room where is located at the above floor. It was found that the distribution of sound pressure levels in the receiving room indicates significant deviation at different frequencies there is more than 5dB drop at 63Hz but 2dB rise at 125Hz at a height of 1.2m when the impact ball is driven, in the other case of a generating tapping machine there is more than 2dB rise at 125Hz at a height of 1.2m due to room modes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1380-1383
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• 2004

The scanning type XY stage is frequently used these days as precision positioning system in equipment for semiconductor or display element. It is requested higher velocity and more precise accuracy for higher productivity and measuring performance. The position accuracy of general stage is primarily affected by the geometric errors caused by parasitic motion of stage, misalignments such as perpendicular error, and thermal expansion of structure. In the case of scanning type stage, H type frame is usually used as base stage which is driven by two actuators such as linear motor. In the point view of scanning process, the stage is used in moving motion. Therefore, dynamic variation is added as significant position error source with other parasitic motion error. Because the scanning axis is driven by two actuators with two position detectors, 2 dimensional position errors have different characteristic compared to general tacked type XY stage. In this study 2D position error of scanning stage is analyzed by 1D heterodyne interferometer calibrator, which can measure 1D linear position error, straightness error, yaw error and pitch error, and perpendicular error. The 2D position error is evaluated by diagonal measurement (ISO230-6). The yaw error and perpendicular error are compensated on the base stage of scanning axis. And, the horizontal straightness error is compensated by cross axis compensation. And, dynamic motion error in scanning motion is analyzed.

• 제어로봇시스템학회논문지
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• 제21권12호
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• pp.1130-1135
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• 2015

The bond pull test is the most widely used technique for the evaluation and control of wire bond quality. The wire being tested is pulled upward until the wire or bond to the die or substrate breaks. The inspector test strength of wire by manually and it takes around 3 minutes to perform the test. In this paper, we develop a 3D vision system to measure 3D position of wire. It gives 3D position data of wire to move a hook into wires. The 3D measurement method to use here is a confocal imaging system. The conventional confocal imaging system is a spot scanning method which has a high resolution and good illumination efficiency. However, a conventional confocal systems has a disadvantage to perform XY axis scanning in order to achieve 3D data in given FOV (Field of View) through spot scanning. We propose a method to improve a parallel mode confocal system using a micro-lens and pin-hole array to remove XY scan. 2D imaging system can detect 2D location of wire and it can reduce time to measure 3D position of wire. In the experimental results, the proposed system can measure 3D position of wire with reasonable accuracy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.437-441
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• 1997

In the conventional remote monitoring system, a user in front of a computer monitor can acquire only 2 dimensional visual information in a passive way. Thus, even thoght the user finds an interesting object from the video image, helshe can hardly acquire additional information on the object such as name. 311 shape, etc. In this paper, an active monitoring system that shows additional information on the selected object is proposed. The active remote monitoring system can calculate the 3D position of the object that is selected in the video images. Then, using the 3D position of the object, other information on the object can be retrieved from the database and shown on the screen. To calculate the 3D position of the object, 2 CCD cameras that can be tilted and panned using 3 stepping motors are used. The algorithm of 3D position calculation and the result of experiments are explained.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.833-836
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• 1995

The Position Sensitive Detector(PSD) is an useful which can be used to measurement the position of an incidence light in detail and in real-time. In this paper, light sources, to be predefinded positions, are used as landmarks and the 2-D PSD signals are used to compensate the position of a running mobile robot. To induce the position compensation algorithm, first, we inspect the error factor, make the error model, and evaluate the error covariance matrix between the real position and estimated position in dead reckoning system. Next we obtain an optimal position compensation algorithm to update the estimated position using extended Kalman filler by the relation of the external light position and it's PSD signal. Through the simulation of navigating a robot the effectiveness of the proposed method is confirmed.

• 대한전기학회논문지:전력기술부문A
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• 제48권12호
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• pp.1537-1543
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• 1999

In this paper, PSD(Position Sensitive Detector) sensor system that estimates position for moving objects in 2D plane is developed. PSD sensor is used to measure the position of an incidence light in real-time. To get the position of light source of moving target, a new parameter calibration algorithm and neural network technique are proposed and applied. Real-time position measurements of the mobile robot with light source is examined to validate the proposed method. It is shown that the proposed technique provides accurate position estimation of the moving object.

• 한국기계가공학회지
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• 제12권5호
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• pp.141-148
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• 2013

There are several problems in the conventional 2-D image processing and 3-D measurement systems. In the case of the 2-D image processing system, it is not possible to detect elevation data. In a 3-D measurement system, it requires a skillful operator and a lot of time for measuring data. Also, there exist data errors depending on operators. The limitation of detecting elevation data in the 2-D image processing system can be solved by laser diodes. In this study an algorithm that measures the accurate data in a subject face to be detected by combining laser diodes and a commercial CCD camera is developed. In the development process, a planar equation is developed using laser diodes and the equation is used to obtain a normal vector. Based on the results, an algorithm that transforms commercial CCD camera coordinates to 3-D coordinates is proposed. The completed measurement method will be applied to replace a manual measurement system for vehicle bodies and parts by an automated system.

• 한국군사과학기술학회지
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• 제3권2호
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• pp.121-130
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• 2000

A practical method is proposed to improve hit probability of the digital gun fire control system, when the measured rate of the tracking sensor becomes biased under some operational situation. For ground moving target it is shown that the well-known Kalman filter which uses position measurement only can be optimally used to eliminate the rate bias error. On the other hand, for 3D moving aircraft we present a new algorithm which incorporate FIR-type filter, which uses position and rate measurement at the same time, and the fixed-lag smoother using position measurement only, and show that it has the optimal performance in terms of both estimation accuracy and response time.

• International Journal of Precision Engineering and Manufacturing
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• 제8권2호
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• pp.64-69
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• 2007

Aerostatic planar XY stages are frequently used as the main frames of precision positioning systems. The machining and assembly process of the rails and bed of the stage is one of first processes performed when the system is built. When the system is complete, the 2D position, motion, and stage flatness errors are measured in tests. If the stage errors exceed the application requirements, the stage must be remachined and the assembly process must be repeated. This is difficult and time-consuming work. In this paper, a method for estimating the errors of a planar XY stage is proposed that can be applied when the rails and bed of the stage are evaluated. Profile measurements, estimates of the motion error, and 2D position estimation models were considered. A comparison of experimental results and our estimates indicated that the estimated errors were within $1{\mu}m$ of their true values. Thus, the proposed estimation method for 2D position and flatness errors of an aerostatic planar XY stage is expected to be a useful tool during the assembly process of guideways.