The second moment method is proposed as a method of obtaining a one dimensional approximation to a two dimensional angularly averaged modulation transfer function for low spatial frequencies. For two orthogonal knife-edge scans of a point spread function, the second moments about the centroid of the corresponding line spread functions are determined. The two second moment values are then used to approximate the two dimensional angularly averaged modulation transfer function. Two rotationally asymmetric point spread functions were used to test the approximation, an equilateral triangle and a rectangle. The results show, for both cases, that in the 1.0 to 0.5 modulation range, there was no difference in the modulation transfer function curves determined by using the approximation and the actual angular average of the modulation transfer function. In the 0.5 to 0.1 modulation range, a difference of only 5% was calculated.

Publication Date


Document Type


Student Type


Degree Name

Imaging Science (BS)

Department, Program, or Center

School of Photographic Arts and Sciences (CIAS)


Edward Granger


Physical copy available from RIT's Wallace Library at TA1632.C875 1984


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