Improved local mean decomposition method

The invention provides an improved local mean decomposition method. Firstly the local maximum value point and the local minimum value point of an original signal are searched, then the spline interpolation is performed on the local maximum value point and the local minimum value point for three times and a signal upper envelope function and a signal lower envelope function are obtained, then a selection indicator is set according to the signal upper and lower envelope functions, and a local mean function and an envelope estimation function are calculated by using the upper and lower envelope functions if the selection indicator meets the spline envelope requirements; and the local mean function and the envelope estimation function are calculated by using a moving average method if the selection indicator does not meet the spline envelope requirements. The spline interpolation method and the moving average method are combined to be used for constructing the local mean function and the envelope estimation funct