Correlations Between G-tilt, Z-tilt, Centroid Motion, and Quad-cell Measurements

Authors

• Jack E. McCrae, Air Force Institute of Technology
• Julianna Sommer, Air Force Institute of Technology
• Santasri R. Bose-Pillai, Air Force Institute of Technology
• Milo W. Hyde IV, Air Force Institute of Technology
• Steven T. Fiorino, Air Force Institute of Technology

Document Type

Article

Publication Date

7-1-2026

Abstract

Correlations between Z-tilt, G-tilt, and centroid motion as a function of thresholding are studied through simulations and analyses. The Z-tilt, or Zernike tilt, is the first moment of the phase distribution over the aperture, while the G-tilt, or gradient tilt, is the average phase gradient over the aperture. It is found that raw centroid motion best correlates with G-tilt, but that even a small amount of thresholding makes Z-tilt the stronger correlation. The Zernike decomposition of the G-tilt is also presented. Using this decomposition, a theoretical value for the correlation between Z-tilt and G-tilt is determined. It is further demonstrated that the quad-cell signal best correlates with Z-tilt even though no thresholding is involved.

Comments

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DOI

10.1364/AO.600816

Source Publication

Applied Optics (ISSN 1559-128X, 2155-3165)

Recommended Citation

Jack E. McCrae, Julianna Sommer, Santasri R. Bose-Pillai, Milo W. Hyde, and Steven T. Fiorino, "Correlations between G-tilt, Z-tilt, centroid motion, and quad-cell measurements," Appl. Opt. 65, H188-H192 (2026)