Geometric distortion calibration using a pinhole mask

M. Service; M. Chun; J. Lu; F. Abdurrahman; O. Lai; D. Fohring; C. Baranec

doi:10.1117/12.2313769

18 July 2018 Geometric distortion calibration using a pinhole mask

M. Service, M. Chun, J. Lu, F. Abdurrahman, O. Lai, D. Fohring, C. Baranec

Proceedings Volume 10703, Adaptive Optics Systems VI; 107034S (2018) https://doi.org/10.1117/12.2313769
Event: SPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, United States

Abstract

Adaptive optics (AO) systems deliver high-resolution images that may be ideal for precisely measuring positions of stars (i.e. astrometry) if the system has stable and well-calibrated geometric distortions. Calibration units equipped with back-illuminated pinhole masks are often utilized to measure instrumental distortions. AO systems on the largest ground-based telescopes, such as the W. M. Keck Observatory and the Thirty Meter Telescope, or with large fields of view, such as the ‘imaka ground-layer adaptive optics experiment, require pinhole positions known to 20 nm to achieve astrometric precisions of 0.001 of a resolution element. We characterized the nonlinear geometric distortion of a simple imaging system using a photo-lithographic pinhole reference grid to be 1650 nm RMS with a final residual of 41 nm RMS (20.5 μas for TMT). Our system model uses fourth order polynomials to model the distortion and allows the reference positions of the pinholes to vary. The nonlinear deviations in the pinhole pattern with respect to the manufacturing design of a square pattern are estimated to be 29 nm over a 1200 mm², which reflects the additional error induced in a distortion measurement when assuming the pattern is perfectly manufactured.

Citation Download Citation

M. Service, M. Chun, J. Lu, F. Abdurrahman, O. Lai, D. Fohring, and C. Baranec "Geometric distortion calibration using a pinhole mask", Proc. SPIE 10703, Adaptive Optics Systems VI, 107034S (18 July 2018); https://doi.org/10.1117/12.2313769

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available