Closed Circuit Televisions

Description

an image of a CCTVClosed circuit televisions (CCTV) are used by individuals who have low vision. A CCTV is a video magnifying system that uses a stand-mounted or handheld video camera to project a magnified image onto a video monitor, television screen or computer monitor. Potential uses for a CCTV include reading your mail, newspapers, magazines, bills, books, prescription bottles, writing cheques, filling out crosswords puzzles, viewing pictures, etc. Most CCTVs come with the following standard features:

  • Provides an enlarged image of the material under the camera
  • Variety of monitor sizes available (3” – 22”)
  • Magnification range (2x – 75x)
  • Controls for magnification, brightness, contrast
  • Auto focusing
  • Polarity options (black text/white background or white text/black background)

 

Stationary CCTVs

These are the "traditional" models of CCTVs. The large monitor or video display is mounted over the camera. Stationary CCTVs have a built-in X-Y table to help move the reading material in the direction you want it to read with a locking mechanism to lock the table in place at any location. The locking feature is enabled when writing under the CCTV. This model is often chosen for prolonged reading tasks as several words or lines of text are displayed at one time. Some of the stationary models offer ‘add-on’ features at an additional cost. This may include:

  • False colours, e.g., blue text/yellow background, yellow text/black background, etc.
  • Position indicators – to help you track your place on the page
  • Line markers and/or masking (horizontal or vertical)
  • Adjustable monitor arm (moved up/down/right/left, tilted, telescoped forward/back)
  • Pre-set button to allow the user to display the text in a preferred magnification and contrast
  • External PC switch allows you to switch between the image from the camera to the PC image

 

CCTVs that use Computer Monitors (Computer Integrated)

These CCTVs connect to a computer monitor. They are not interchangeable with a television; they are made for integration with a computer monitor. They offer access to the print material, the computer application, or both using a split screen function. Not all models offer the split screen feature. Some of them are made lightweight and simple to set up in order to be more portable. Add on features of this type of CCTV include:

  • Freeze frame capabilities
  • Controlled by keystrokes from your PC
  • Distance mode available – for those individuals who need to switch between seeing near and distance
  • Taking snapshots of images to store them onto your laptop

 

Portable CCTVs

These CCTVs are considered portable in that you can use an existing TV monitor with them or they have a built-in portable monitor included. This model is often chosen when reading is required in multiple rooms/location, e.g., at home at the cottage. Most units are designed for easy transport, set-up and storage. Some but not all portable CCTVs are computer compatible. Portable CCTVs can offer additional features such as:

  • Detachable cameras to use with additional arms
  • Optional XY table
  • Battery operated option
  • Features controlled with a remote control
  • Focus lock
  • Rotating camera for near, distance and self-viewing
  • Carrying case for easy transport

 

Hand Held CCTV's

A hand-held CCTV is often chosen for those who want access to print material while “on the go.” They can be used for reading prices tags, ingredients on food packaging, menus at a restaurant, sales receipts, etc. This type of CCTV is not chosen for lengthy reading task as the smaller display size makes this difficult to do. Each handheld unit varies with on what features they offer. Consider the following features when looking at a handheld unit:

  • Magnification levels
  • Viewing modes, e.g., white/black, black/white, yellow/black, etc
  • Brightness adjustment
  • Display size
  • Size and Weight of the unit
  • Freeze frame capabilities
  • Handwriting feature
  • Distance capabilities
  • Camera indicator light
  • Battery indicator
  • Battery life and re-charge time
  • Power saving mode
  • Accessories included, e.g., AC adapter charge, batteries, carrying case with belt loop, neck/wrist strap, video cable connection to television/ computer monitor

 

Points to Ponder

Cost aside, there are several factors that need to be considered before purchasing a CCTV. Here are some things to consider when trying out the various models:

  • Is the eye condition progressive or variable in nature? Consider a CCTV that has a larger screen size and the ability to magnify to higher ranges?
  • Any sensitivities to light? Consider a CCTV with brightness control and reverse polarity feature?
  • Any sensitivities to glare? Consider a CCTV with a Liquid Crystal Display (LCD) display or monitor that has less glare reflecting off it. Having a monitor that tilts can also help reduce the amount of glare.
  • Are there other concerns that would affect the use of a CCTV, e.g., cognitive or manipulative skills?
  • What display features are needed? Is it easier to read standard or reversed polarity text? Are certain colour contrasts easier to read, or is there the need for seeing true colours (such as when reading maps and pie charts)
  • Any ergonomic considerations need to be taken into account? E.g., adjustable heights monitor, location of controls, type of controls, etc.
  • Has the compatibility of the CCTV with accessory equipment been taken into account? E.g., ports, operating systems, etc.

 

Resources

CCTV Manufacturers

SNOW does not endorse any of the following software/hardware. These links are provided for information purposes only.

 

Articles

Ehrlich, D. (1987). A comparative study in the use of closed-circuit television reading machines and optical aids by patients with retinitis pigmentosa and maculopathy. Ophthalmic and Physiological Optics, 7(3), 293-302.

Lowe, J.B. & Drasdo, N. (1990). Efficiency in reading with closed circuit television for low vision. Ophthalmic and Physiological Optics, 10(3), 225-233.