In many situations it is desirable to obtain an image that visually describes measured lens MTF data. Since the sharpness of a camera lens changes continuously across the field of view, the characteristics of the lens need to be determined at many positions within the image. In short, the proposed simulation method consists of two parts. First, the point-spread function (PSF) at a limited number of field positions is constructed using Zernike polynomials. The polynomial coefficients at a specified field position are determined by fitting the calculated MTF for these PSFs to the measured MTF data. The other part interpolates Zernike coefficients for all other relevant positions within the image. In this way it is possible to find a sufficiently accurate PSF at any arbitrary field point. By utilizing a generalized non-translational invariant summation of PSFs, the sharpness at any field point in the image can be simulated. This system also has the advantage that the sharpness at different focusing positions can be determined quite easily. It is also a fairly simple matter to include effects such as distortion and vignetting. In the present paper, examples of simulations are shown and advantages as well as drawbacks of the method are discussed.

Date Published: 3 March 2008
PDF: 12 pages
Proc. SPIE 6817, Digital Photography IV, 68170O (3 March 2008);

Published in SPIE Proceedings Vol. 6817:
Digital Photography IV
Jeffrey M. DiCarlo; Brian G. Rodricks, Editor(s)