Fig. 1. Optical path structure

Fig. 2. Time domain plot of noise

Fig. 3. tanh function

Fig. 4. Time domain plot of the intrinsic signal with added noise

Fig. 5. Filtered result using the standard Kalman filter algorithm

Fig. 6. Relative error after filtering using the standard Kalman filter algorithm

Fig. 7. Filtering results using the DBK filter algorithm

Fig. 8. Relative error of amplitude after filtering using the DBK filter algorithm

Fig. 9. Comparison of filtering results between the original and improved Kalman filter algorithms

Fig. 10. Calculation result of noise covariance

Fig. 11. LabVIEW FPGA programming flow

Fig. 12. DBK intrinsic component filtering algorithm module

Fig. 13. Optical sensor experimental platform

Fig. 14. Filtered intrinsic component