Fig. 1. Time frequency domain relationship of lidar transmission signal and reception signal

Fig. 2. Schematic diagram of ILC-based laser frequency correction scanning device

Fig. 3. Basic process of pre-distortion algorithm

Fig. 4. DFB laser parameters under different static currents. (a) Spectra of laser under different currents; (b) wavelength and SMSR variation of laser under different currents

Fig. 5. Modulation bandwidth spectrum of light source

Fig. 6. Experimental results of DFB laser instantaneous frequency and voltage pre-distortion algorithm. (a) Comparison of control voltage and beat frequency signal waveform before correction; (b) comparison of control voltage and beat frequency signal waveform after correction; (c) instantaneous frequency before correction; (d) instantaneous frequency after correction

Fig. 7. Experimental results of DFB laser instantaneous frequency and residual pre-distortion iteration. (a) Comparison of instantaneous frequency and residual of up sweep period　before correction; (b) comparison of instantaneous frequency and residual of up sweep period before calibration; (c) comparison of instantaneous frequency and residual of down sweep period before correction; (d) comparison of instantaneous frequency and residual of down sweep period after correction

Fig. 8. Comparison of beat frequency signal spectra and experimental results of iteration. (a) Frequency domain of beat frequency signal before and after correction; (b) relationship between number of iterations and degree of nonlinearity

Fig. 9. Experimental results of instantaneous frequency and residual pre-distortion iteration of DFB laser under small injection current condition. (a) Comparison of instantaneous frequency and residual of up sweep period before correction; (b) comparison of instantaneous frequency and residual of up sweep period after correction; (c) comparison of instantaneous frequency and residual of down sweep period before correction; (d) comparison of instantaneous frequency and residual of down sweep period after correction

Fig. 10. Stability of laser frequency scanning linearity within 6 h

Fig. 11. Schematic diagram of distance measurement experimental device

Fig. 12. Image of object capture signals at different distances on laser ranging platform

Fig. 13. Distance measurement experimental results. (a) Comparison between measured distance and actual distance; (b) error value corresponding to distance variation