Dispersion is a very common phenomenon in the broadband optical systems. Chromatic confocal technology uses the chromatic aberration of lens to decode the axial displacement of the sample surface by the focus-wavelength of the reflected spectrum. Dispersion characters of the light source and sample surface greatly influence the reflected spectrum except the useful chromatic aberration, leading to focus-wavelength shift in many displacement measurements. Thus a novel and convenient strategy is proposed to correct the dispersion of the unstable light source or the alterable sample surface. The strategy provides a self-reference spectrum from a prior scanning process to normalize the reflected spectrum. Theoretical analysis demonstrates that the normalized reflected spectrum meets well with the point spread functions of the passive unit, which includes the fiber coupler, probe and spectrometer. Hence, the focus-wavelength of the normalized reflected spectrum is insusceptible of the light source and sample surface. Robustness tests with different light sources and sample surfaces showed that, the biggest wavelength shift of the self-reference strategy was reduced to less than 1/4 of that from the non-reference strategy. The results demonstrated that the proposed self-reference dispersion correction significantly improves the robustness and accuracy against different light sources and sample surfaces in chromatic confocal displacement measurement.

色散是宽带光学系统中非常普遍的现象。色共聚焦技术使用透镜的色差通过反射光谱的聚焦波长来解码样品表面的轴向位移。除了有用的色差之外，光源和样品表面的色散特性极大地影响反射光谱，从而导致许多位移测量中的焦点波长偏移。因此，提出了一种新颖且方便的策略来校正不稳定光源或可变样品表面的色散。该策略提供了来自先前扫描过程的自参考光谱，以对反射光谱进行归一化。理论分析表明，归一化反射光谱与无源单元的点扩展函数吻合得很好，其中包括光纤耦合器，探头和光谱仪。因此，归一化反射光谱的聚焦波长对于光源和样品表面是不敏感的。在不同光源和样品表面上进行的稳健性测试表明，自参考策略的最大波长偏移降低到小于非参考策略的1/4。结果表明，提出的自参考色散校正显着提高了在共焦位移测量中针对不同光源和样品表面的鲁棒性和准确性。在不同光源和样品表面上进行的稳健性测试表明，自参考策略的最大波长偏移降低到小于非参考策略的1/4。结果表明，提出的自参考色散校正显着提高了在共焦位移测量中针对不同光源和样品表面的鲁棒性和准确性。在不同光源和样品表面上进行的稳健性测试表明，自参考策略的最大波长偏移降低到小于非参考策略的1/4。结果表明，提出的自参考色散校正显着提高了在共焦位移测量中针对不同光源和样品表面的鲁棒性和准确性。