Video Magnifiers Final.PMD - AbleData

and perform close work such as sewing. An image of the material to bemagnified is captured by a digital video camera, sometimes called a CCD(charge-coupled device) camera. The digital video camera is connected toa monitor or screen on which magnified images are displayed. Some videomagnifiers have their own monitor or screen, while others are connectedto a separate computer or television.Video magnifiers are often called closed circuit televisions, or CCTV’s, becauseearly models used conventional television screens to display images.The camera and television screen were directly connected in a closed circuit,leading to the term “CCTV.” The two terms are still more or less interchangeable,even though many video magnifiers today use computermonitors or thin-film transistor (TFT) flat screen displays.Video magnifiers can be divided into two basic categories—desktop andportable.Desktop Video MagnifiersDesktop video magnifiers feature a camera mounted over a tray on whichthe material to be magnified is placed. Some have a built-in monitor andare known as “stand-alone” magnifiers. Others are designed to connect toa television or personal computer.Most desktop video magnifiers have a “reading tray” that holds the materialto be magnified. This tray can be moved from side to side or forwardsand backwards, in order to position the desired part of the material directlyunder the camera. The reading tray is known as an “X/Y tray,” inreference to the x-y coordinates that indicate the horizontal and verticalposition of points on a graph.Desktop video magnifiers usually take about as much desk space as a personalcomputer, and perhaps a little more because of the need for freespace in which to move the reading tray. Because of their built-in monitors,most stand-alone desktop models are too heavy to be called portable.Page 2 December 2003 ABLEDATA Fact Sheet on Video Magnifiers