Fig. 1. Overall scheme of the system

Fig. 2. Electrical pulse signals generated by FPGA

Fig. 3. Parameters of the electrical pulse signal

Fig. 4. Voltage of Stokes signal

Fig. 5. Display curve on SignalTap II

Fig. 6. Implementation process of FPGA cumulative iterative average filtering

Fig. 7. Flowchart of nonlinear wavelet transform threshold denoizing

Fig. 8. Experimental system diagram

Fig. 9. Effect of cumulative iterative average denoizing. (a) Original signal; (b) 1000 iterations; (c) 8000 iterations; (d) 16000 iterations

Fig. 10. Enlarged effect of cumulative iterative average denoizing. (a) 1000 iterations; (b) 8000 iterations

Fig. 11. Temperature curve after average denoizing of 8000 cumulative iterations

Fig. 12. Temperature curve after threshold denoizing of nonlinear wavelet transform

Fig. 13. Temperature curves after heating. (a) 40 ℃; (b) 60 ℃; (c) 80 ℃