Fig. 1. Comparison of different denoising methods for 20 db noise

Fig. 2. Comparison of different denoising methods for 30 db noise

Fig. 3. RMSE and SNR changes of different wavelets and different thresholds for 20 db noise

Fig. 4. RMSE and SNR changes of different wavelets and different thresholds for 30 db noise

Fig. 5. RMSE and SNR changes of different wavelet decomposition levels for different noise

Fig. 6. RMSE and SNR changes of different denoising methods for 20 db noise

Fig. 7. RMSE and SNR changes of different denoising methods for 30 db noise

Fig. 8. Raman Spectrum of experimental sample
(a): Noisy Raman spectrum; (b): Denoised spectrum by analyst; (c): Denoised spectrum by BP network