Multiple-wavelength interferometry is, like classical interferometry, a coherent method, but it offers great flexibility in sensitivity by an appropriate choice of the different wavelengths and it can be operated on rough surfaces. The accuracy of this method depends essentially on the signal processing and on the properties of the source. Practical considerations for distances in the range of several meters with micrometer resolution are given.
"High-accuracy distance measurements with multiple-wavelength interferometry," Optical Engineering 34(8), (1 August 1995). http://dx.doi.org/10.1117/12.205665