Approximation implementation approach for Gaussian filtering in roundness measurement

Gaussian filter acts as the filter for roundness signal processing and a new implementation approach for Gaussian filter is presented. Based on the theory of B-spline function, the variational principle with the tension condition and the convolution characteristic of Gaussian filter with small scale, the approximation filter of Gaussian filter is concluded, which has the amplitude characteristic deviation from Gaussian filter less than 1% and the zero-phase-shift characteristic. The algorithm for the approximation filter consists of the zero-phase-shift filtering and the weighing filtering which loop two times. The algorithm is both simply in its structure and high in its filtering efficiency. The method of cycle continuation solves the edge effects of digital filtering based on the periodicity of the roundness measurement signal. The approximation filter is also efficient and accurate for the implementation of Gaussian filter in the application of roundness measurement.