Fig. 1. Spectrum of optical frequency comb光频梳频谱

Fig. 2. (a) Principle of frequency domain interference method; (b) the experimental setup of the measurement system(a)频域干涉法原理图; (b) 测距系统实物图

Fig. 3. Relationship between actual distance and measured distance实测距离与被测距离关系

Fig. 4. Broadening of the pulse envelope using original FFT: (a) ; (b) . 传统FFT法脉冲包络展宽现象　(a) ; (b)

Fig. 5. Principle of equal frequency interval resampling等频率间隔重采样原理

Fig. 6. Repetition and hopping of the measurement result传统FFT法结果重复和跳变

Fig. 7. Comparison of simulation effect when τ = 3 × 10^–11:　(a) Equal frequency interval resampling; (b) peak position fitting 当τ = 3 × 10^–11时, 仿真效果对比　(a) 等频率间隔重采样; (b) 峰值位置拟合

Fig. 8. Peak position fitting simulation. Original FFT:　(a) 3.335 × 10^–12, (b) 3.335 × 10^–11, (c) 7.500 × 10^–11. Equal frequency interval resampling and peak position fitting (d) 3.335 × 10^–12, (e) 3.335 × 10^–11, (f) 7.500 × 10^–11峰值定位仿真传统FFT　(a) 3.335 × 10^–12, (b) 3.335 × 10^–11, (c) 7.500 × 10^–11; 等频率间隔重采样和峰值位置拟合(d) 3.335 × 10^–12, (e) 3.335 × 10^–11, (f) 7.500 × 10^–11

Fig. 9. Simulation error of three methods传统FFT、等频率间隔重采样和峰值位置拟合法仿真误差比较

Fig. 10. Effect contrast of peak position fitting. Original FFT: (a) L = 5.8600 mm, (b) L = 16.9850 mm, (c) L= 27.9100 mm. Equal frequency interval resampling and peak position fitting: (d) L = 5.8600 mm, (e) L = 16.9850 mm, (f) L = 27.9100 mm 峰值定位效果对比仅传统FFT　(a) L = 5.8600 mm, (b) L = 16.9850 mm, (c) L = 27.9100 mm; 等频率间隔重采样和峰值位置拟合(d) L = 5.8600 mm, (e) L = 16.9850 mm, (f) L = 27.9100 mm

Fig. 11. Correction of repetition result by three methods: (a) 0.4997 mm; (b) 0.9998 mm; (c) 4.9980 mm传统FFT、等频率间隔重采样和峰值位置拟合法分辨力修正效果对比　　(a) 0.4997 mm; (b) 0.9998 mm; (c) 4.9980 mm