• Title/Summary/Keyword: Optical triangulation

Search Result 57, Processing Time 0.029 seconds

Accuracy Verification of Optical Tracking System for the Maxillary Displacement Estimation by Using of Triangulation (삼각측량기법을 이용한 광학추적장치의 상악골 변위 계측에 대한 정확성 검증)

  • Kyung, Kyu-Young;Kim, Soung-Min;Lee, Jong-Ho;Myoung, Hoon;Kim, Myung-Jin
    • Maxillofacial Plastic and Reconstructive Surgery
    • /
    • v.34 no.1
    • /
    • pp.41-52
    • /
    • 2012
  • Purpose: Triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline. This point can be fixed as the third point of a triangle with one known side and two known angles. The aim of this study was to find a clinically adaptable method for applying an optical tracking navigation system to orthognathic surgery and to estimate its accuracy of measuring the bone displacement by use of triangulation methods. Methods: In orthognathic surgery, the head position is not fixed as in neurosurgery, so that a head tracker is needed to establish the reference point on the head surface byusing an optical tracking system. However, the operation field is interfered by its bulkiness that makes its clinical use difficult. To solve this problem, we designed a method using an Aquaplast splinting material and a mini-screw in applying a head tracker on a patient's forehead. After that, we estimated the accuracy of measuring displacements of the ball marker by an optical tracking system with a conventional head tracker (Group A) and with a newly designed head tracker (Group B). Measured values of ball markers' displacements by each optical tracking system were compared with values obtained from fusion CT images for an estimation of accuracy. Results: The accuracy of the optical tracking system with a conventional head tracker (Group A) is not suitable for clinical usage. Measured and predictable errors are larger than 10 mm. The optical tracking system with a newly designed head tracker (Group B) shows 1.59 mm, 6.34 mm, and 9.52 mm errorsin threeclinical cases. Conclusion: Most errors were brought on mainly from a lack of reproducibility of the head tracker position. The accuracy of the optical tracking system with a newly designed head tracker can be a useful method in further orthognathic navigation surgery even though the average error is higher than 2.0 mm.

Sensor Structure and Signal Processing System for Precision Optical Displacement Measurement (초정밀 광학식 변위 측정을 위한 센서 구호 밀 신호 처리 시스템)

  • O, Se-Baek;Kim, Gyeong-Chan;Kim, Su-Hyeon;Gwak, Yun-Geun
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.18 no.8
    • /
    • pp.40-47
    • /
    • 2001
  • Optical measurement methods make it possible to detect object displacements with high resolution and noncontact measurements. Also, they are very robust against EMI noises and have long operation range. An optical triangulation sensor is one of widely used displacement measurement sensors for its sub-micron resolution, fast response, simple structure, and low cost. However. there are several errors caused by inclinations of a surface. speckle effects, power fluctuations of light sources, and noises of detectors. In this paper, in order to minimize error effects, we performed error analysis and proposed a new structure. Then, we setup a new modeling method and verify it through simulations and experiments. Based on the new model. we propose a new sensor structure and establish design criteria. Finally, we design a signal processing system to overcome a resolution-limited problem of light detectors. The resolution of the proposed system is 0.2${\mu}{\textrm}{m}$ in 5mm operating range.

  • PDF

The Optical Measurement and Quantitative Analysis of Algesia in Spodoptera litura Larva

  • Chen, Ying-Yun;Chang, Rong-Seng;Tsai, Mi-Yin;Chen, Der-Chin
    • Journal of the Optical Society of Korea
    • /
    • v.19 no.2
    • /
    • pp.169-174
    • /
    • 2015
  • Muscle vibration measurement has long been an unique scientific study, in general, and the direct reaction of animals to feel pain (algesia), either from vascular or muscle contraction, is a complex perceptual experience. Thus this paper proposes a way to measure animal algesia quantitatively, by measuring the changes in muscle vibration due to a pinprick on the surface of the skin of a Spodoptera litura larva. Using the laser optical triangulation measurement principle, along with a CMOS image sensor, linear laser, software analysis, and other tools, we quantify the subtle object point displacement, with a precision of up to $10{\mu}m$, for our chosen Spodoptera litura larva animal model, in which it is not easy to identify the tiny changes in muscle contraction dynamics with the naked eye. We inject different concentrations of formalin reagent (empty needle, 12% formalin, and 37% formalin) to obtain a variety of different muscle vibration frequencies as the experimental results. Because of the high concentrations of reagent applied, we see a high frequency shift of muscle vibration, which can be presented as pain indices, so that the algesia can be quantified.

Characteristics of the Laser Displacement Sensor Using Optical Triangulation Method (광삼각법을 이용한 레이저 변위 센서의 특성 연구)

  • Park, Jong-Sung;Jeong, Kyu-Won
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.7
    • /
    • pp.40-50
    • /
    • 1999
  • Recently, a laser displacement sensor is widely used for the manufacturing automation. The sensor is generally composed of a diode laser and a light receiving device. The diode laser emits a laser beam and the receiving device detects the light reflected from the measured object. The object position is obtained based upon triangulation method. As a light receiving device, a PSD is usually utilized since its structure is very simple and rugged and has a high accuracy. Although the theoretical relationship for this sensor had been developed, the characteristics of the sensor have not been much experimentally studied. In this paper, several experimental results will presented. The measurement accuracy is affected by the surface conditions such as the reflectance characteristics, the angle of the object's surface and the laser intensity. In addition, it is found that the PSD and the signal processing circuit have nonlinearities and showed that those nonlinearities can be reduced by controlling the emitting laser intensity.

  • PDF

3-Dimensional Profile Measurement of Free-Formed Surfaces by Slit Beam Scanning Topography (슬릿광 주사방법에 의한 자유곡면의 삼차원형상 측정)

  • 박현구;김승우;박준호
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.17 no.5
    • /
    • pp.1202-1207
    • /
    • 1993
  • An optical method of slit beam scanning topography is presented for the 3-dimensional profile measurement of free-formed surfaces. A slit beam of laser is projected in a scanning mode and its illuminated trajectory on the object is captured by using a CCD camera. The 3-dimensional coordinates of the trajectory is then computed by using the given geometry between the slit beam and the camera, so that the whole surface profile of the object can be obtained in a successive manner. Detailed optical principles are described with special emphasis to lateral are discussed to demonstrate the measuring performances of the slit beam scanning topography proposed in this study.

Development of a Noncontact Three Dimensional Foot Form Measurement System with Optical Triangulation (광삼각법을 이용한 비접촉 3차원 족형 측정 시스템 설계)

  • 박인덕;안형회;송강석;이희만;김시경
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.9 no.5
    • /
    • pp.368-373
    • /
    • 2003
  • This paper presents a cost-effective 3D foot scanner system that provides the 3-dimensional point cloud foot data to design the custom footwear. To measure the 3-dimensional point cloud data of the foot, a CCD camera, a Non-Gaussian laser line projector and optical triangulation method are employed. Furthermore, the integrated system employs a measurement base, a frame grabber, a CCD moving cart, a stepping motor and a computer. The measurement result is saved as 3D dxf format and it could be converted to 2D essential data fer a shoe design. The experimental results demonstrate that the proposed system have the decent resolution of 1mm which is enough for last and shoe design.

Development of a profile measuring system for conductor roll (전기도금 롤의 형상 측정시스템 개발)

  • Choi, Yong-Jun;Jun, Sung-Bai;Lee, Eung-Suk;Kim, Hyo-Sung;Jang, Ji-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.10
    • /
    • pp.1730-1741
    • /
    • 1997
  • In this paper, we developed a surface profile measuring system and a profile measuring software for EGL conductor roll. For the profilemeter, we designed a linear guided control system with Laser displacement sensors and developed a 3-dimensional software. Additionally, the AC motor and AC motor driver were used to control the precise position of linear guide system. The measuring principle of the Laser sensor is optical triangulation method. Also, two Laser sensors were used to remove the disturbance and vibration effects of the linear guide system.

Development of Three Dimensional Scanner for Anthropometric Measurement (인체측정용 3차원 스캐너 제작)

  • Kim, Min-Hyo;Nam, Yun-Ja
    • Journal of the Ergonomics Society of Korea
    • /
    • v.20 no.3
    • /
    • pp.77-88
    • /
    • 2001
  • A three dimensional body scanner for anthropomentric measurement has been developed. In this study, the slit laser beam projection method followed by digital image processing was used to provide accurate spatial data with the typical optical triangulation method to overcome the many difficulties in traditional in accurate and time-consuming tactic measurement method using rulers and gauges. Compared with other commercialized scanners. this system can obtain a relatively wide range of data at a much lower cost by the specially designed scanning process such as the simultaneous acquisition of vertical and horizontal body cross-section profiles.

  • PDF

The Development of adaptive optical dimension measuring system (적응형 광학 치수 측정 장치 개발)

  • 윤경환;강영준;백성훈;강신재
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.690-695
    • /
    • 2004
  • A new dimension measuring method for the measurement of diameter of an object has been developed using laser triangulation. The 3-D data of an object was calculated from the 2dimensional image information obtained by the laser stripe using the laser triangulation. The system can measure the diameter of hole not only in a normal plane but also in an incline plane. We can experiment with magnification that is optimized according to size of object using zoom lens. In this paper, the theoretical formula and calibration of the system were described. The measuring precision of the system was investigated by experiment.

  • PDF