The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform

Toyohiko Yatagai - One of the best experts on this subject based on the ideXlab platform.

Harith Ahmad - One of the best experts on this subject based on the ideXlab platform.

  • theoretical and experimental studies on coupler based fiber optic displacement sensor with Concave Mirror
    Optik, 2012
    Co-Authors: Sulaiman Wadi Harun, Hangzhou Yang, Hamzah Arof, Harith Ahmad
    Abstract:

    Abstract A new fiber optic displacement sensor (FODS) is proposed and demonstrated using a multimode fiber coupler as a sensor probe and a Concave Mirror as a reflective target. A mathematical model is also developed to investigate the performance of proposed FODS at various coupling ratio, fiber diameter, and surrounding media. Three slopes are obtained for the displacement response where the third slope starts at a displacement position of twice the focal length. The numerical results show that higher performance is attained at lower coupler ratio of 50:50 or smaller core diameter. The results also show that the proposed FODS has a potential application in liquid and gas chemical sensors. The experimental performances are also investigated for the proposed sensor where it is observed that the second peak of the displacement curve is located at exactly two times of the focal length or 20 mm.

  • Fiber-optic salinity sensor using fiber-optic displacement measurement with flat and Concave Mirror
    IEEE Journal on Selected Topics in Quantum Electronics, 2012
    Co-Authors: Husna Abdul Rahman, Sulaiman Wadi Harun, Muhammad Yasin, Harith Ahmad
    Abstract:

    A simple intensity modulated displacement sensor is proposed for sensing salinity based on different concentration of sodium chloride (NaCl) in deionized water. The proposed sensor uses a 594-nm He-Ne laser as light source due to the high absorbance of NaCl within that wavelength. The peak voltage and its position of the displacement from both flat and Concave Mirror are studied. For a concentration change from 0% to 12%, the peak voltage decreases linearly from 2.46 to 1.48 mV, while its corresponding position from the flat Mirror increases linearly from 1.00 to 1.35 mm with a linearity of more than 96% and 99%, respectively. Similarly, the peak voltage corresponding to the displacement with Concave Mirror decreases linearly from 3.67 to 3.57 mV, while its position increases linearly from 1.20 to 1.45 mm with a linearity of more than 98% and 95%, respectively. From the experimental results, it is concluded that as the concentration or density of NaCl increases, the peak voltage decreases proportionately. The stability, high sensitivity, simplicity of design, and low fabrication cost make this sensor suitable for chemical, pharmaceutical, biomedical, and process-control application.

  • micro displacement sensor with multimode fused coupler and Concave Mirror
    Laser Physics, 2011
    Co-Authors: Sulaiman Wadi Harun, Moh Yasin, Harith Ahmad
    Abstract:

    Fiber optic displacement sensor is demonstrated using a multimode fused coupler probe and a Concave Mirror target. It is observed that a focal length of the Concave Mirror make a significant influence to the displacement response, which illustrates three linear slopes with the second slope peaks at the position that is in vicinity of two times of the focal length. The highest sensitivity of 0.56 mV/mm is obtained with an infinity focal length and it is decreased as the focal length of the Concave Mirror decreases. The widest linear range of approximately 3.3 mm is observed in the third slope region with focal length of 6.0 mm. The highest linear range obtained with the use of 50:50 coupler.

  • Theoretical and experimental studies on Concave Mirror‐based fiber optic displacement sensor
    Sensor Review, 2011
    Co-Authors: Hangzhou Yang, Sulaiman Wadi Harun, Harith Ahmad
    Abstract:

    Purpose – The purpose of this paper is to investigate, theoretically and experimentally, a Concave Mirror‐based fiber optic displacement sensor performance for three‐axes directional measurements.Design/methodology/approach – Mathematical model is constructed based on spherical Mirror properties of the Concave Mirror and the simulated result is found to be in good agreement with the experimental results.Findings – Both theoretical and experimental results show that the focal length and radius of the Concave Mirror make significant influence to the displacement response. In the x‐axes measurement, six linear slopes are obtained with four of them are located in the vicinity of the position, two times of the focal length. The maximum measurement range of about 20 mm is obtained using a focal length of 10 mm. In the y‐ and z‐axes displacement measurements, the linear range increases as the diameter of Concave Mirror increases. The longest linear range of 8 mm is achieved at Mirror radius of 10 mm.Originality/...

  • theoretical and experimental studies on Concave Mirror based fiber optic displacement sensor
    Sensor Review, 2011
    Co-Authors: Hangzhou Yang, Sulaiman Wadi Harun, Harith Ahmad
    Abstract:

    Purpose – The purpose of this paper is to investigate, theoretically and experimentally, a Concave Mirror‐based fiber optic displacement sensor performance for three‐axes directional measurements.Design/methodology/approach – Mathematical model is constructed based on spherical Mirror properties of the Concave Mirror and the simulated result is found to be in good agreement with the experimental results.Findings – Both theoretical and experimental results show that the focal length and radius of the Concave Mirror make significant influence to the displacement response. In the x‐axes measurement, six linear slopes are obtained with four of them are located in the vicinity of the position, two times of the focal length. The maximum measurement range of about 20 mm is obtained using a focal length of 10 mm. In the y‐ and z‐axes displacement measurements, the linear range increases as the diameter of Concave Mirror increases. The longest linear range of 8 mm is achieved at Mirror radius of 10 mm.Originality/...

Yuichi Kikuchi - One of the best experts on this subject based on the ideXlab platform.

Xiangqian Jiang - One of the best experts on this subject based on the ideXlab platform.

  • Enhancement of measurement accuracy of optical stereo deflectometry based on imaging model analysis
    Optics and Lasers in Engineering, 2018
    Co-Authors: Feng Gao, Xiangqian Jiang
    Abstract:

    Abstract This paper represents a novel analysis method to improve the measurement accuracy of an optical stereo deflectometry system. A novel imaging model is proposed to research the relation between the phase uncertainty and the normal uncertainty of a stereo deflectometry system. By comprehensively considering the influence on the sampling phase error and the normal error, the system's screen pixel size and the period of fringe displayed on the screen are analyzed to enhance the measurement accuracy. To verify the proposed method, experiments using a common LCD (liquid crystal display) monitor and a screen with Retina Display have been investigated respectively. Experimental results demonstrate using the screen with Retina Display can significantly improve the measurement accuracy of a stereo deflectometry 2.38 times in accuracy due to the ultra-fine pixel size. A stereo deflectometry system based on the proposed method has been built to measure a standard flat Mirror and a standard Concave Mirror. The global measurement accuracy of the flat Mirror and the Concave Mirror can reach 69.7 nm and 96.8 nm respectively.

  • Performance Analysis and Evaluation of Geometric Parameters in Stereo Deflectometry
    Engineering, 2018
    Co-Authors: Feng Gao, Xiangqian Jiang
    Abstract:

    Abstract This paper presents a novel geometric parameters analysis to improve the measurement accuracy of stereo deflectometry. Stereo deflectometry can be used to obtain form information for freeform specular surfaces. A measurement system based on stereo deflectometry typically consists of a fringe-displaying screen, a main camera, and a reference camera. The arrangement of the components of a stereo deflectometry system is important for achieving high-accuracy measurements. In this paper, four geometric parameters of a stereo deflectometry system are analyzed and evaluated: the distance between the main camera and the measured object surface, the angle between the main camera ray and the surface normal, the distance between the fringe-displaying screen and the object, and the angle between the main camera and the reference camera. The influence of the geometric parameters on the measurement accuracy is evaluated. Experiments are performed using simulated and experimental data. The experimental results confirm the impact of these parameters on the measurement accuracy. A measurement system based on the proposed analysis has been set up to measure a stock Concave Mirror. Through a comparison of the given surface parameters of the Concave Mirror, a global measurement accuracy of 154.2 nm was achieved.

Daisuke Barada - One of the best experts on this subject based on the ideXlab platform.