Theoretical Analysis on Gauge Block Length Measurement by Excess Fraction method

The method of Excess Fraction (EF) has been widely employed to determine the integer fringe order in interferometric metrology. In this paper, we describe the principle of EF method which selects the optimum difference cj between the real length and nominal length. Besides, theoretical analysis and numerical simulation based on the experimental data of employed wavelengths and corresponding excess fraction values from three different wavelength groups have been implemented to illustrate the influence of experimental errors on the final result.