PURPOSE: To obtain a road-surface-condition detecting method that can easily be installed and provides detection over a relatively-broad range, by deciding the state of a road surface on the basis of difference in direct reflection factor and diffused reflection factor of light on the road surface according to the state of the road surface and a road-surface temperature.
CONSTITUTION: Of light projected from projector 1 and then reflected on road surface 4, light of direct reflection and that of diffused reflection are photodetected by photodetector 11 for direct reflection and photodetector 21 for diffused reflection respectively. Output signals of filters 14 and 24, containing information on the state of the road surface obtained from the light of direct reflection and that of diffused reflection, are input to comparators 15 and 16, and 25 and 26 respectively, thereby deciding one of the wet state, snow state and dry state. Further, microprocessor 40 classifies finally the state of the road by four kinds of dry, wet, frozen and snow states on the basis of the decision result of the road-surface state by the information from the light of direct reflection and that of diffused reflection, and a temperature detection signal from radiation thermometer 31. Thus, the state of the road surface can accurately be detected over a broad range.
| JP4830909 | Particle measuring device |
| JP3257413 | LASER BEAM MACHINE AND ITS METHOD |
| JPH0519578 | TONER CONCENTRATION SENSOR |
FUKAMIZU HIROSHI
NAKANO MASASHI
HIRAO IICHI
IBA KUNIO
YAMAZAKI TAROU
REO GIKEN KK