著者

中島 利郎 仲嶋 一 鷲見 和彦 的場 修

出版者

The Society of Instrument and Control Engineers

雑誌

計測自動制御学会論文集 (ISSN:04534654)

巻号頁・発行日

vol.46, no.12, pp.746-753, 2010 (Released:2011-12-19)

参考文献数

10

被引用文献数

3 2

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We have developed a road surface condition detection system using near-infrared light, which enables remote measurement. The developed system can detect the difference of road surface conditions as dry, water, ice, and snow.In this case, we focused on the light-absorption characteristics of water. To remove the affect of the thickness of the water layer, we have proposed a measured metrics as absorption ratio at two wavelengths. The absorption spectra were measured by using a water layer of 1mm thickness. The experimental results showed that the absorption peak shifts to longer wavelength when the water state changes into ice state. A ratio of absorption coefficients at 1300nm and 1410nm is constant even when the layer thickness changes from 0.2mm to 0.8mm. This result indicates that the proposed absorption ratio can be used as a criterion to detect the water state or the ice state.We have also proposed a reflected-light separation method by using polarization characteristics of light. There are two reflected light components. One is the reflected light from the water surface and the other is one from the road surface. The reflected light from the water surface keeps the polarization state of the input. However, the polarization state from the road surface becomes random state because of the rough surface. To remove the surface reflection of the water layer, orthogonal polarization detection of input and output pair is effective. This is confirmed by the experiment.We made a prototype of the above-described detection principle and it was tested by the experiment. As a result, the feasibility of determining road surface conditions such as dry, water and ice is confirmed by simultaneous measurement of light-absorption characteristics and reflection characteristics.

著者

中島 利郎 仲嶋 一 的場 修

出版者

The Society of Instrument and Control Engineers

雑誌

計測自動制御学会論文集 = Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.45, no.6, pp.291-297, 2009-06-30

参考文献数

8

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This paper reports a sensor for the plant inspections to detect leaking vapor. Plants are usually inspected by patrolling inspectors. It requires high level skills to selectively detect abnormal phenomena occurring in various types of equipment under the complicated environments. In this research, we developed a remote detecting sensor for the vapor leaking from piping, which is one of the priority control items inside plants. The basic principle of the sensor is specifically to sense the scattered light when laser beam is illuminated on the vapor. It is also discovered in our basic experiments that there is big difference in the polarization property between the light scattered by vapor and surface structures inside plants. The sensor can discriminate the light scattered by vapor from other types of scattered light utilizing the difference of the polarization property, then detecting the light scattered by vapor only. A prototype model is fabricated for substantiating the basic property of leaking vapor detection. As a result, it is confirmed that the prototype model not only has sufficient detecting capability, but can selectively detect vapor only. In conclusion, it is confirmed that the developed sensor satisfies the requirements for the plant inspection sensors, and has sufficient capability for practical usage.