Video magnifiers (CCTV)
What is a video magnifier?
A CCTV or video magnifier is a simple way of producing large text, images and maps for people with some useful vision. Printed material and objects can be placed under a camera and the magnified image is displayed on a television screen or computer monitor.
Video Magnifiers are not a replacement for hand magnifiers, but do have real advantages for some tasks. These include the ability to vary magnification levels, to get very high levels of magnification, to get a comfortable reading distance, and to vary reading distance. Many people find they can read more comfortably and therefore for longer periods with a video magnifier than with a hand magnifier. While there is not absolute way of knowing whether a video magnifier will help a particular individual without them trying one for themselves, as a general guide if someone can read the largest banner headlines in a newspaper then a video magnifier is likely to be of use to them.
The video magnifier image can be black and white or full colour. Many black and white systems offer the option of switching the foreground and background colours between dark text on a light background and light text on a dark background (reversing polarity). In addition they may offer a choice of foreground and background colours. As well as the default choice of colour image view, most colour image video magnifiers offer a choice of foreground and background colours, and mono view.
Desktop video magnifiers
The most common type of video magnifier is intended for desktop user. Most desktop video magnifiers have a camera, which is in a fixed position some distance above the desktop. The printed material is placed on the reading table, which can be moved left to right and backwards and forwards.
The image is viewed on an integrated monitor and can be adjusted for contrast, magnification and colour to suit the user. A few desktop video magnifiers have a camera on an anglepoise type stem, instead so there is some flexibility of position. Desktop magnifiers can offer a magnification range as low as 1.5 times and as high as 60 times, although the range is usually narrower than this.
Portable video magnifiers
Portable CCTVs, intended for the more mobile user, are being developed all the time. In some cases, the camera unit is portable, but a standard monitor/TV screen is required to display the image, in other cases the CCTV may have it’s own small integrated viewing screen or may be connected to a laptop. Most portable video magnifiers, and many video magnifiers that use a television, have a hand-held camera similar to a computer mouse.
The camera is placed directly on the page, or other object such as a medicine bottle, and moved across it to read the material underneath. There are a few video magnifiers with other camera and display options. A head mounted camera exists, and there is a portable video magnifier where the user wears a pair of spectacles on which the image is displayed.
Some portable units have fixed magnification levels, whilst others offer full user control, although the range of magnification on portable units is more limited than a desktop CCTV.
Pocket video magnifiers
These are pocket or handbag sized CCTVs designed for you to carry around with you at all times. They are useful for reading labels in shops, notices, bills, menus and magazines whilst travelling. They have a 10cm integrated screen and are available at up to 5x or 7x magnification depending on the product. Magnification is increased by moving the CCTV closer to the object.
Video magnifiers that plug into a television
Video magnifiers that plug into a television tend to be cheaper than other options as you buy only the camera. This is of course assuming you already have the television and are prepared for it to be used at times for video magnification. CCTVs that display the image on a television are usually in the form of a handheld camera that rests on the paper and then moves across the paper or object, or it may look like a lamp that can be angled to sit above the document. The magnification range for these cameras tends to be more limited and sometimes depend on the size of television that the image is displayed on. Many of these units are portable.
PC sharing video magnifiers
A few video magnifier systems will link to a PC, allowing the screen image to be shared between the video magnifier picture and the computer display. These video magnifiers are often referred to as “screen sharing” or “split-screen” video magnifiers.
- Date: July 2009