• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.338-344
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• 2010

Both ends of welding line are often closed by wall in the welding of ship blocks. In this research, seam tracking sensing system for butt welding in the condition with wall was developed. Seam tracking sensing system measures position of carriage from wall and detects root-pass of welding line. The system consists of the laser displacement sensors and ultrasonic sensors. The laser displacement sensor reciprocal1y rotates by the motor and measures a distance from laser sensor to the welding material. The ultrasonic sensor measures a distance between welding system and walls. The distance measured by the ultrasonic sensor is used to get X(driving) position and to determine initial and end point of the weld line. Y(weaving) and Z(height) of the weld line are obtained by the distance measured by the laser displacement sensor and the orientation of the sensor. The sensing system includes the controller that is independent from the welding carriage. The seam tracking sensing system is attached to both side of welding carriage so that interference between welding torch and sensing system can be avoided during the welding. And both side sensing system minimize dead zone. Finally, developed sensing system was adhered to welding carriage and verified usefulness by experiments.

• Journal of Sensor Science and Technology
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• v.12 no.5
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• pp.225-230
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• 2003

Nowadays, laserthermia is widely used to treat malignant tumors with generating heat as the one of minimal invasive surgeries. Generally, the laserthermia probe system consists of the fiber-optic laser and light guides, image guide and temperature sensor. It is very important to measure the temperature of treating tumor and make a stable temperature ($42{\sim}43^{\circ}C$) during the treating time. Therefore, laserthermia probe needs temperature sensor which can measure it exactly and fast. In this study, to develop a new type of temperature sensor with LC(liquid crystal) and optical fiber, the reflectivity of LC according to the temperature changes are measured. Also, the relationships are derived from the results.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.839-845
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• 2006

A laser docking system provides a centimeter-level accuracy distance from jetty mounted laser sensors in order to help a vessel to approach to a pier. It is very accurate & useful, whereas there are too many considerable problems. Laser sensors of the laser docking system need to be correctly positioned and installed on a jetty to allow for full range of vessels to be berthed and to consider loading condition and tidal variations. Above all, the laser docking system is expensive and its service coverage is limited. In order to solve these problems, CDGPS positioning method using GPS satellites has been proposed. This paper presents that, through RHDOP simulation, the previous CDGPS positioning method using only GPS satellites is not able to provide the continuous service with centimeter-level positioning accuracy. And this paper proposes a pseudolite-augmented positioning method for vessel docking in order to solve the problem of the continuous service on the previous CDGPS positioning method. In this paper, pseudolite is used to aid in CDGPS positioning. This paper shows that the proposed method can provides the continuous service through comparison analysis of RHDOP simulation results between the GPS satellite constellation and the pseudolite-augmented GPS satellite constellation. Furthermore, it is shown that the proposed positioning method satisfies the positioning performance required for vessel automatic docking at a test bed designed for performance evaluation.

• Journal of Animal Environmental Science
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• v.17 no.2
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• pp.93-100
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• 2011

This study was conducted to verify the applicability of robot milking system through acquisition and analysis of model teat's position information using scanning range finder (SRF). Model teats, same size and shape as real teats, were designed to analyze the properties according to the material, distance error and angle error of the sensor. In addition, 2-dimensional distance information of each teats was obtained at same time with 4 teat models and the result were as follows. 1. In the case of the fingers on the experiment for selection of materials for teat model, the distance error was from 4.3 mm to 1.3 mm, average was 2.8 mm as a minimum record. In the case of rubber material, average distance error was 4.3 mm. So, this material was considered to be a most suitable model. 2. The distance error was maximum at 100 mm distance. The more distance increased, the less error increased up to 300 mm. Then the error increased after 300 mm and decreased again. 3. The maximum angle error of 10.1 mm was measured at $170^{\circ}$, in case of $70^{\circ}$ the error was 0.2 mm as a minimum value. There was no specific tendency to error of angle. 4. In the 2-dimensional location error for 4 teat models, distance error was 3.8 mm as minimum and 7.2 mm as maximum. The angle error was $1.2^{\circ}$ as maximum. All of errors were included within the accuracy of sensor, the robot milking system was considered to be applicable to measure the distance of teats due to the measuring velocity of SRF and the hole size of teat-cup.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.132-142
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• 2014

Stereo camera is drawing attention as an essential sensor for future intelligence robot system since it has the advantage of acquiring not only distance but also other additive information for an object. However, it cannot match correlated point on target image for low textured region or periodic patterned region such as wall of building or room. In this paper, we propose a stereo matching technique that increase the matching performance by fusing belief propagation stereo matching algorithm and local distance measurements of 2D-laser range finder in order to overcome this kind of limitation. The proposed technique adds laser measurements by referring quad-tree based segment information on to the local-evidence of belief propagation stereo matching algorithm, and calculates compatibility function by reflecting over-segmented information. Experimental results of the proposed method using simulation and real test images show that the distance information for some low textured region can be acquired and the discontinuity of depth information is preserved by using segmentation information.

• Journal of Welding and Joining
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• v.17 no.2
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• pp.53-60
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• 1999

Conventionally, CCD camera and vision sensor using the projected pattern of light is generally used to inspect the weld bead defects. But with this method, a lot of time is needed for image preprocessing, stripe extraction and thinning, etc. In this study, laser vision sensor using the scanning beam of light is used to shorten the time required for image preprocessing. The software for deciding whether the weld bead is in proper shape or not in real time is developed. The criteria are based upon the classification of imperfections in metallic fusion welds(ISO 6520) and limits for imperfections(ISO 5817).

• Journal of Digital Contents Society
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• v.11 no.2
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• pp.117-122
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• 2010

This is a study on the analysis of vibration mode of a laser doppler. We measure the vibration mode of a doppler and analyze each component, and want to estimate three dimensional properties from 2-dimensional data. The vibration mode relies on a range detector that uses a distance sensor. Since the outputs are determined by the measured distance, we want to study how 3-dimensional vibration mode is generated from 2-dimensional ones. The study will include the patterns of generating a 3-dimensional vibration mode as well as the relationship between the distance and the vibration mode.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.3
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• pp.379-385
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• 2012

This paper developes the navigation visual aid supporting a watch officer's situation awareness and analyzes its performance test result. Developing the equipment made from composite video sensor which transfer video signal, ranger laser measurement model which search out distance, Pan/ Tilt, center control device. The developed equipment with Pan/Tilt was made from high performance video sensor and ranger laser measurement. To make a real ship test, we carried on setting the developed equipment on ship, observed a danger factor and analyzed a image, and from that we can evaluate marine environment awareness. Through this result, the developed equipment can show effective ability of the awareness of the clearer check and resolution situation when compare with the binocular.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.451-454
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• 2013

자동차의 타이어는 자체의 하중을 지지하고 구동력과 제동력을 노면에 전달 한 뿐만 아니라 노면으로부터 받는 충격을 완화하며 자동차의 진행 반행을 전환, 유지하는 등 자동차에 아주 중요한 역할을 담당하는 부품이다. 하지만 이러한 타이어에 약간의 이상이 발생을 하더라도 운전자 및 동승자의 안전을 영향이 있는 중요한 부품 중의 하나이다. 타이어의 문제는 여러 가지가 있을 수 있지만 일반적으로는 일반 마모와 이상마모로 두가지로 나뉠 것이다. 일반적인 마모는 자동차 주행 중의 마모로 적당한 주행거리에 교체 하면된다 하지만 이상마모는 일반적인 마모와 달리 각 타이어가 따로 마모가 되거나 타이어 일부분이 마모가 되는 것이다. 현재까지 이상마모를 점검하는 방법으로는 정비사가 타이어를 눈과 손으로 점검하여 편마모인지 아닌지를 판단을 하고 있기 때문에, 하지만 편마모인지 아닌지를 점검하는 기준이 다르고 타이어 마다 틀려 운전자는 애매모호한 기준에 당황 할 수밖에 없다. 그래서 본 논문에서는 이러한 단점을 보완 하고자 복 수개의 레이저 센서를 이용하여 각 타이어 마다 인지 아닌지를 체크 하는 시스템을 설계하여 주관적인 판단을 극복하고 객관적이고 정확한 판단을 내릴 것이다.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.1
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• pp.17-21
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• 2019

In this paper, a high precision straightness measurement system has been developed at low cost using a visible laser and CMOS image sensor. CMOS image sensor detected optical image and the variation of straightness was calculated by image processing. We have observed that the error of the developed straightness measurement system was 0.9% when a distance of 3m between laser and image sensor. And it can be applied to 3D printer and any other areas.