High accuracy high speed Gaussian filter in surface metrology

Both (1 + x(2))(-n) and (sin x/x)(n) functions are very close to the Gaussian distribution for large value of n. Based on these functions, two new algorithms are developed for designing high accuracy and high speed recursive type Gaussian digital filters. The relationships between the Gaussian filtering and the classical 2RC filtering and between the Gaussian filtering and the moving average filtering are also discussed.