Geometrical error correction based on sensitivity equations for accurate specular surface measurement with deflectometry

Abstract

Deflectometry systems are very sensitive to geometry since the geometric uncertainty could easily generate low-order shape errors. The geometric calibration of the display screen is one of the important geometric calibration procedures. We have analyzed the geometry sensitivity of the display screen for flat mirror measurement with deflectometry. Sensitivity equations are derived to explicitly describe the relationship between the geometric uncertainty and the shape errors. The correctness and effectiveness of the proposed sensitivity equations have been verified with numerical simulations and preliminary experiments. The proposed theory can help to understand the effect of geometry sensitivity on deflectometry tests and evaluate the system performance. Moreover, it provides a guide for the improvement of the testing accuracy for low-order shapes.

KEYWORDS:

• Surface measurements
• figure
• optical instruments
• metrology

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number U20A20215].