| Zernike polynomials used in Sensoft – our wavefront sensor software: expressions for the first 7 terms | ||
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Zernike polynomials are generally expressed in terms of the normalized radius r of the pupil, and the azimuthal angle φ , by the following expression : rn cos (m φ + φ0) This is the general expression in terms of the Seidel polynomials. The Annular Zernike polynomials, on the other hand, involve aberration balancing, in which aberrations of a lower order are combined with those of the higher order for reducing the wavefront error. For example, the expression for 3rd order spherical aberration also contains a defocus term. They also take into account the effect of the annulus e of the optical element. φ0 is the zero-offset : it gives the orientation of the particular aberration with respect to the x-axis. | |
| Aberration | Annular Zernike polynomials | Seidel polynomials |
| Defocus (n=2,m=0) |
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| Tilt (n=1,m=1) |
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| Coma (n=3,m=1) |
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| Spherical 3rd order (n=4,m=0) |
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| Astigmatism (n=2,m=2) |
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| Triangular Coma (n=3,m=3) |
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| Quadratic Astigmatism (n=4,m=4) |
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