Figure
T
riangulation
Range nder
Scanning
Head
camera
con
tains
a
one dimensional
Hamamatsu
lateral
e ect
photo
dio
de
and
fron
t
end
ampli er
for
the
top
and
b
ottom
signals
The
phototransistors
are
used
to
trigger
the
micro
con
troller
to
start
and
stop
sampling
at
the
b
eginning
and
end
of
the
scan
The
t
w
o
photo
dido
de
signals
along
with
the
phototransistor
signals
are
sen
t
to
the
main
rac
k
unit
Although
a
video
camera
could
b
e
used
to
image
the
re ected
laser
sp
ot Bo
v
w
e
opted
to
use
the
lateral
e ect
photo
dio
de
system
b
ecause
of
the
atten
uation
of
bac
kground
ligh
t
from
sync
hronous
detection
and
the
lac
k
of
an
y
image
pro
cessing
o
v
erhead
Sync
hronous
Detector
and
P
osition
Computation
The
laser
is
amplitude
mo
dulated
with
Khz
square
w
a
v
e
The
rac
k
unit
con
tains
a
sync
honous
detection
circuit
as
w
ell
as
the
sum
and
di erence
computations
The