COMPUTERIZED TRAVEL AID (1980):

• Micro-processor controlled sonar device allowing the audible output to be changed (ROMs can be re-programmed). Speech can also be output.
• Max. range is about 35ft.
• In general, the 80s saw a great deal of research centered around using computers to process an image allowing for the opportunity to convey far more information to the user.

'DYNAMIC ULTRASONIC RANGING SYSTEM AS A MOBILITY AID FOR THE BLIND' (~1993/94):

• Prototype built around a PVC tube resembling a long cane.
• Four computer controlled ultrasonic sensors provide real-time information on distance and height within 5m of the user.

vOICe (1994):

• Converts images taken with a standard T.V. camera into sound patterns on a "1-1 image to sound mapping ensuring preservation of the visual information."
• Each picture is sub-divided into 4096 pixels (64 * 64), and each pixel can be one of 16 shades of grey.
• Every column is then translated into a sound (top pixel is high pitched, bottom pixel is low pitched and intermediate pixel has intermediate pitch), and then summed allowing them to be heard siultaneously.
• The visual image is scanned from left to right outputting the sound of each column.
• Pictures are taken and converted to sound every second.
• Real-time processing.

'APPLICATION OF MACHINE VISION TECHNOLOGY TO THE DEVELOPMENT OF AIDS FOR THE VISUALLY IMPAIRED': Dublin University, School of Engineering.

• Combination of shape, colour and motion is used to provide an auditory description of an image obtained through a camera linked to the Prolog environment.

1. Shapes:Identified by obtaining certain characteristics and then comparing them against reference characteristics. Described using synthesised voice output.
2. Colour: Tone of sound is mapped to hue, loudness to brightness.
3. Motion: Centroid Tracking and Motion Tracking are seperately experimented.