Members of the electro-optics community have essentially redefined the modulation transfer function (MTF) for focal plane arrays in different ways. Although these particular discrepancies make little difference below the Nyquist frequency, they are significant for system which push limits and process above-Nyquist frequency data. This issue is briefly reviewed, and it is shown that consistency with the Fourier method of defining MTF for focal plane arrays implied sample phase averaging, separation of the transferred sinusoid remnant with the input frequency from those of alias frequencies and recognition that the contrast ratio expression for MTF is a special case. Differences in the implications of discrete sampling analysis and the sample- and-hold operation are presented. In this approach MTF and alias effect are separated so that MTF represents a single-valued, global transfer entity and alias is defined by two different characterization metrics.

Date Published: 10 June 1996
PDF: 11 pages
Proc. SPIE 2743, Infrared Imaging Systems: Design, Analysis, Modeling, and Testing VII, (10 June 1996); doi: 10.1117/12.241957

Published in SPIE Proceedings Vol. 2743:
Infrared Imaging Systems: Design, Analysis, Modeling, and Testing VII
Gerald C. Holst, Editor(s)