Methods of Guidance

I've been having a think about how best to guide the user around the environment, avoiding obstacles and other people.

I'm assuming we have maybe some kind of overhead all-seeing camera system (an "eye in the sky") which we will have to work on the practicalities of later. There are a few current ways to guide a blind person as to when to turn left or right, or to stop:

• using a guide dog which follows its own path. The blind person holds a rigid lead and as the dog moves about, the human detects this and instinctively follows it.
• using a human guide. Similar to the guide dog, only the blind person may hold onto the elbow of the guide and move about as they do.
• self-guidance using a cane.

All of these share the feature of instant analogue (see below) feedback. Much like separate carriages of a train or parts of an articulated lorry are attached to and follow each other perfectly around bends, the blind person and guide (whether dog, friend, or cane) move as a single unit but with the sense of sight simply in a separate 'unit' or carriage.

The question is, how do we effectively achieve the same ability to guide the user with instant feedback from an electronic piece of equipment?

• a voice system saying 'go left' or 'go right' or 'halt' (optionally in a cheesy digitised American accent). This has major drawbacks:

1. Processing of the sound and conversion into movement of the user is extremely slow compared to other methods.
2. In a noisy environment such as a supermarket sounds from an electronic speaker or earpiece can be missed.
3. The instructions from the device are digital. Simply saying 'go left' is not much use as this could mean any of: turn slightly to the left to correct your course, make a 90 degree turn out of an aisle, or even jump left to avoid an oncoming obstacle. 'Analogue' guidance - some way of implying the amount of turn - is needed.

• force feedback motor (currently my favourite idea). A series of gyroscopes inside a handheld, belt-mounted or even arm-mounted unit can be shifted so the unit literally pulls the user in one direction or another. A sharp push backwards can signify 'stop' and gentle pulls to the left or right indicate the amount of turn in that direction required, in much the same way as a gentle pull from a guide dog or assistant.

I'll keep having a think about other methods and we can see what Mike has to say when we see him on Monday about all this, too.