New method for improving SNR of fringes detection

On basis of satisfying counter and subdivision, a new arrangement method for photoelectric cells, that the difference cells are adjacent, is present to improve signal noise ratio of fringes detection. This method and two traditional methods have been analyzed by integral equations. Applying in three founded models including random noise, AC amplitude and DC adrift ones, and in comparison with two traditional detection methods by theoretical and experimental analysis, the detection SNR of the new method is improved to root2similar to2root2 times of that of traditional methods according to different fringes' signal. This method can dramatically restrain DC adrift of light intensity even if the fringes' signal is faint. It provides a theoretical basis for realizing spot measurement of single frequency that requires high resistance to noise.