Description of image information content and image transfer efficiency by single parameters

It is proposed that the number
N*
, given by
N*=4ab
[\int\min{0}\max{\infin}T(f) df]^{2}
, is equal to the number of picture elements in an image within which the noise-free modulation transfer function
T(f)
of the image device (display) is uniform and isotropic;
a
and
b
are the edge lengths (mm) of a rectangular format, and
f
is the spatial frequency (cycles/mm). An equation for
N*
, that applies to nonuniform and anisotropic modulation transfer functions is also given. A picture element transfer efficiency
E*
is defined as (
N*/N*'
), where
N*'
is the number of picture elements transferred to the image (display) by an "ideal" device.