
Chapter 11
Transfer Functions; Hubble Space
Telescope
The results in the preceding chapter provide a complete description of the
characteristics of a perfect or near-perfect image of a distant point object. The
response of an optical system to a set of point objects or, more generally, an
arbitrary intensity distribution was not considered in that analysis. Clearly this
response depends on factors in addition to the PSF such as, for example, blurring
due to image motion or detector pixel size. Factors such as these are most easily
included by using the theory of transfer functions to describe the system response
and image characteristics.