In addition to simple control of imaging commands, I also desired some automated functionality. For example, I wanted the base station to automatically know my wherabouts, so that additional information about each exposure could be kept for later use, as well as for immediate use.
Ideally, a tape measure would be used
to measure the location on the ground where I was standing,
and the height of the flash lamp above the ground, and instruments would
be used to determine its azimuth and elevation (direction of aim).
However, due to time constraints, it was more typical that I would
count the distance in `paces' (number of footsteps), and report these numbers
verbally (using two-way radio)
back to my assistant at the base station taking notes. This
procedure itself, because it required the attention of an
assistant
, was
undesirable, so I included a pedometer in my shoes to
automate this counting process (initially on an electro-mechanical
counter manufactured
by Veeder Root, and later on the wearable computer with the Veeder Root
counter as a backup to occasionally verify my count).
Due to count errors (in both the computer and backup), I also
experimented with the use of ceramic phono cartridges, piezo elements,
and resistive elements, using some hysteresis in the counting circuitry.
Experiments in replacing the pedometers with radiolocation were not particularly successful (this was, of course, long before the days of the Global Positioning System (GPS)). One approach that was somewhat successful was the use of radar for estimating short distances and rough velocities with respect to the ground. For this purpose, I designed and built a small wearable radar system. This invention proved more useful later for other projects, such as a safety device to warn if someone might be sneaking up from behind, and later as an assistant to the visually impaired who could use it to ``feel'' objects ``pressing'' against them before contact. Some years later, in the late 1980s, I presented wearable radar to the Canadian National Institute for the Blind, but it was never widely adopted, mainly due to the poor performance arising from the limited capabilities of my wearable computers of this era. With Today's more sophisticated wearable computers, capable of implementing variations of the chirplet transform[8] in realtime (to obtain radar acceleration signatures of objects in the wearer's vicinity), I hope to revive my ``BlindVision'' project of the 1980s[9].