Beware of wrong definitions.
Where to start ? Well let’s get one definition straight to start with. Perhaps my pet
hate are those who refer co Digital Imaging Systems as ‘Optical Disks’. Now this is
simply wrong. The term optical disk simply describes a device which reads or writes
information from/to a special disk using the light from a small low-power
semiconducting laser – hence optical. It so happens that optical disks are usually
used by imaging systems as the means of storing the images once captured. But they
are only a small part of the system and that use is not the sole use to which optical
disks are put. The converse is also true, in that optical disks are not the only way of
storing the images. Storage to tape is quite practical, although admittedly, less
convenient. Images could be stored on the hard disks of computers with
considerably less technical complication than optical disks, although the quantity
of images stored this way would be tiny by comparison; none the less, it’s possible.
So, please – less emphasis on the storage medium and more emphasis on what the
systems are about.
What is an Imaging System ?
Ok, tow let’s start at the beginning. The idea of imaging systems is to store images,
be they pictures, text, drawings, documents – or what have you, in some way that
they can be pulled back and looked at in the future. At the same time, an imaging
system must satisfy other criteria: The storage medium must take up less room than
the original, it’s no use replacing hundreds of files in cardboard folders with
something which takes up the same or more room – that costs more. The
information must be easily accessible by those who need it, and the cost of storage
and access must be less than the cost of storing and accessing the information in its
original form. Substantially cheaper if the high capital cost of any alternative storage
medium is to be offset by the savings in cost of storage and access.
Mind you, many storage systems are unnecessary anyway. Very often, the custodians
of storage systems don’t ask the obvious question, “What are we keeping this for
anyway ?” But that’s not my problem. I think about alternative storage systems, it’s
not my job to philosophise over why other people should need them.
An imaging system consists of a number of discrete components: a scanner for
getting the images into the computer; a display system for having a look at the
images; a compression system for reducing the raw size of the images to something
more easily stored; a storage system to keep the images; a hard copy system to
reprint the images if desired; and most important of all a computer system to control
what does what, and to find things once stored.