METHOD OF REMOTE MEASUREMENT OF SURFACE ROUGHNESS PARAMETERS Russian patent published in 2014 - IPC G01B11/30 

FIELD: measuring instrumentation.

SUBSTANCE: method of remote measurement of surface roughness parameters relates to data and measurement instrumentation. For roughness measurement, probing emission beam is directed onto the surface in study, an area lit by emission is formed, parameters of reflected light are measured, lit spot size x at the surface in study is changed within 0 to L, distribution function for root-mean-square deviation of roughness height by dependence Rq(x) and its derivative Rq'x(x), and root-mean-square value of roughness height is determined by the formula: $$Ra=\frac{1}{L}{\displaystyle \underset{0}{\overset{L}{\int }}\sqrt{R{q}^2(x)+2Rq(x)R{q}_x^{\text{'}}(x)xdx}}\text{, }\left(\text{1}\right)$$ (1), while the surface is lit in turns at two wavelengths, optical images of lit areas of the object surface are registered in direction of mirrored reflection, and root-mean-square value of roughness height Rq is determined by the formula: $$Rq=\frac{{\lambda }_1{\lambda }_2}{\pi \cos \psi }\cdot \sqrt{\frac{-\ln k_{12}+\ln a}{{\lambda }_1^2-{\lambda }_2^2}}\text{, }\left(\text{2}\right)$$ (2), where k₁₂ is video signal ratio for all elements; i and j images; u_ij are values of video signals of images obtained at wavelengths λ₁ and λ₂; ψ is a plate lighting angle; N is a number of elements in field image line for light reflected from the object surface; K is the number of lines in field image of light reflected from the object surface.

EFFECT: surface roughness measurement by surface lighting at two wavelengths.

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