| 摘要 |
In a process and apparatus for determining the condition of a road surface, light backscattered from a road surface is divided into spectral components and the spectral intensity distribution of the backscattered light is analyzed. The wavelength-dependent backscattered light spectrum of a dry road surface is arranged with a mathematical function with free parameters. This function is multiplied by an exponential absorption term which describes the light transmission of a water layer of a defined thickness in order to obtain a mathematical function for the wavelength-dependent distribution of the backscatter intensity (as it impinges on the receiver). Using the actual measured values, the free parameters of the function can then be calculated to obtain a best possible approximation. This among other things, results in a determination of the thickness of the water layer. In order to implement the process, the system is a spectrometer which uses an absorbing element applied directly to a CCD sensor line in place of a dispersive element.
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