[en] The minimization of the total variation regularization method for γ spectra smoothing is studied and solved by the convex optimization technique. Through the trade-off curve the method for the determination of the optimal trade-off factor, which compromising the cost function and the penalty function namely the total variation regularization, is introduced. The comparison between the traditional methods including moving averaging, Savitzky-Golay in addition to wavelet denoising and the method proposed shows that the latter is more effective as a whole in such peak zones as the lower peak disturbed by a higher peak nearby, doublet multiplets and the big statistical fluctuation peak. Besides, the parameter of the proposed method is easier to be determined. (authors)