Abstract :
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Imaging systems construct an (output) image in response to
(input) signals from diverse types of objects. They can be
classified in a number of ways, e.g. according to the radiation or
field used, the property being investigated, or whether the images
are formed directly or indirectly. Medical imaging systems, for
example, take input signals which arise from various properties of
the body of a patient, such as its attenuation of x-rays or reflection
of ultrasound. The resulting images can be continuous, i.e. analog,
or discrete, i.e. digital; the former can be converted into the latter
by digitization. The challenge is to obtain an output image that is
an accurate representation of the input signal, and then to
analyze it and extract as much diagnostic information from
the image as possible.
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