METHOD OF AND DEVICE FOR THICKNESS MEASUREMENT OF THICK PETROCHEMICAL FILMS ON WATER SURFACE

A method of thickness measurements of thick petrochemical films on a water surface has includes irradiating a surface by an optical beam, receiving a reflected signal, analyzing the dependence of intensity of the reflected signal on a wavelength, determining a film thickness based on the analysis, using three wavelengths for irradiation of the surface, selecting the wavelengths from conditions n 2 ⁢ lambda 1 lambda 2 = 2 ⁢ n 2 ⁡ ( lambda 2 ) lambda 2 , where n2 (lambda1) and n2(lambda2) are refraction coefficients of petrochemical product at the wavelengths: lambda1 and lambda2, lambda3 is equal to a wavelength of absorption maximum of petrochemical product, and using for the determination of the film thickness results of the analysis of intensity of the reflected signal at the three wavelengths.