Some new deformation formulas about variance and covariance

Based on the idea of the difference method, in this paper, the difference method is applied to the calculation of the variance and covariance. The variance and covariance formulas are transformed as some new formulas by the difference method. The articles presented some original new variance and covariance formulas whose form that contains the individual difference, and leads to some corresponding new expansion formulas. The calculation of the variance and covariance about this method is less implicated with the changes of the overall sample. Finally, the theoretical analysis and practical application of image denoising show the feasibility of the new formula.