Point spread function

A lens system which forms image of a point source object is called as point spread function (or) PSF. Point spread function is also called as Fraunhofer diffraction pattern, impulse response and Green’s function.

point spread function

Figure: Above figure was generated by Zemax

</p> <p>\[\quicklatex{color="#000000" size=25}</p> <p>E_{\left(ip\right)}=\ E_{\left(ip\right)}\left(0\right){\left[\frac{{2J}_1\left({\pi q^'}/{\lambda F}\right)}{\left({\pi q^'}/{\lambda F}\right)}\right]}^2\]</p> <p>
 Eip – Image irradiance, J– Bessel function, λ – Wavelength


Properties of point spread function (PSF):

  • PSF can be computed from pupil function by squaring its fourier transform.
  • Peak irradiance of PSF strongly depends on wavelength λ.
  • PSF forms depends upon the shape of the pupil boundaries.


Robert R. Shannon and James C. Wyant, “Applied optics and Optical engineering”, Academic press, Inc. Vol. 7, ISBN 0-12-408608-X (v. 8), 1980.

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