Base on the observation and analysis of the super twisted nematic liquid crystal special diffraction phenomena which display in the electric field were observed and the analyzed,the differences of the interlace diffractive order in certain conditions are discovered,the relationship between liquid crystal\'s internal refractive index and the associated factor.

Based on wavelet analysis, a kind of method is brought forward to improve the diffraction image processing precision of viscose filament diameter.

This paper gives a solution to define the diffusion state of diffraction images edge, and presents two mathematical methods to calculate inspection results.