Scor­pio News


April–June 1988 – Volume 2. Issue 2.

Page 28 of 35

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.

Page 28 of 35