Fig. 1. Principle of spectral coding technology

Fig. 2. Principle of chromatic confocal measurement method

Fig. 3. Images received by color camera when sample is at different heights

Fig. 4. Research idea of color conversion algorithm

Fig. 5. RGB color space and HSI color space. (a) RGB; (b) HSI

Fig. 6. Experimental setup of chromatic confocal measurement system

Fig. 7. Results of calibration experiment and linear fitting. (a) Calibration; (b) linear fitting

Fig. 8. Photograph of measuring block step

Fig. 9. Results of step experiment

Fig. 10. Photograph of one-yuan coin

Fig. 11. Three-dimensional reconstruction result of “yuan” character

Fig. 12. Three-dimensional reconstruction result of “yuan” character after error correction

Fig. 13. Three-dimensional reconstruction result of “1” character after error correction