Chapter

Range nding

Adv

an

tages

of

Laser

Range nders

Laser

Range nders

ha

v

e

the

capabilit

y

of

trac

king

ob

jects

in

free

space

without

am

bi 

guit

y

The

laser

highly collimated

b

eam

pro

vides

a

unique

sample

p

oin

t

that

enables

this

metho

d

to

accurately

trac

k

particular

ob

jects

o

v

er

large

ranges

in

distance 

In

addition 

the

amoun

t

of

time

it

tak

es

the

ligh

t

to

reac

h

the

target

and

return

as

re ec 

tion

can

b

e

accurately

measured 

enabling

one

to

use

the

sp

eed

of

ligh

t

as

a

reference

for

measuring

distance 

as

incorp

orated

in

to

a

v

ariet

y

of

laser

range nders 

Sonar

can

also

b

e

used 

but

the

tra

v

el

time

of

sound

is

orders

of

magnitude

longer

than

that

of

ligh

t 

There

are

also

other

optical

range nding

tec

hniques

that

rely

on

triangulation 

but

these

simply

tak

e

adv

an

tage

of

the

unique

sampling

p

oin

t

or

pattern

and

do

not

use

the

time of  igh

t

of

the

b

eam 

Radar

and

sonar

generally

ha

v

e

m

uc

h

broader

b

eams 

th

us

cannot

b

e

used

to

easily

image

the

in

tricacies

needed

to

trac

k

precise

h

uman

hand

gesture