Nonlinear error compensation algorithm for signal resolution of chromatic confocal measurements

•Nonlinear errors severely interfere with the accuracy of chromatic confocal measurements at the submicron scale.•Nonlinear error stems from the deviation between the wavelength-distance mapping and the polynomial model.•The proposed method can effectively record the nonlinear error in calibration a...

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Bibliographic Details
Published in:Measurement : journal of the International Measurement Confederation 2024-02, Vol.226, p.114091, Article 114091
Main Authors: Dai, Jiacheng, Zeng, Wenhan, Zhong, Wenbin, Jiang, Xiangqian (Jane), Lu, Wenlong
Format: Article
Language:English
Subjects:
Chromatic confocal
Error compensation
Regression tree model
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Summary:•Nonlinear errors severely interfere with the accuracy of chromatic confocal measurements at the submicron scale.•Nonlinear error stems from the deviation between the wavelength-distance mapping and the polynomial model.•The proposed method can effectively record the nonlinear error in calibration and compensate it in measurement.•The results show that the method can achieve a 40 % accuracy improvement over a 4 mm range. The mechanisms of the nonlinear error, primarily stemming from the deviation of the polynomial model fitting the wavelength-distance mapping relationship in chromatic confocal measurement, have been elucidated. A compensation method is proposed for the nonlinear error, based on a regression tree model. Through calibration experiments using our chromatic confocal sensor, an impressive improvement of over 40 % in precision could be achieved by our proposed compensation method, which advances from ±1 μm to ±0.6 μm within a 4 mm measurement range.
ISSN:0263-2241
1873-412X
DOI:10.1016/j.measurement.2023.114091