Measurement of the period of straight interference fringes and its application in phase detection

The period of interference fringes is an important parameter in precision measurement.In order to detect the period of interference fringes simply and fast but not inaccurately,a simpler and practical digital image processing algorithm was adopted to detect the period of interference fringes.The image data processing software was designed on the MATLAB platform and the factors affecting the measurement accuracy of the period of fringes were analyzed.The demand of the fringes inclination was given.The algorithm was used in the detection of phase-plate,and the phase of the phase-plate was acquired.The precision of phase detection reached λ/20~λ/50 or π/10~π/25.This result is largely helpful to the thickness and refractive index detection of the phase object.