
4-11Image Sensors
Light
intensity
Frame #1 Frame #2 Frame #3
Time
Time
Time
Time
Time
(a)
(b)
(c)
(d)
Pulse train
output
Frequency
output
Clock pulse
output
Pulse width
output
FIGURE 4.14 Dierent output waveforms that can be produced by the oscillatory and nonoscillatory methods.
Wa
veform
in (a
)
sh
ows
an ar
bitrary
in
cident
il
lumination
in di
erent
fr
ames
. In ea
ch
fr
ame,
th
e
in
cident
il
lumina-
tion
is de
pendent
on (b
)
th
e
nu
mber
of ou
tput
sp
ikes,
(c
)
th
e
fre
quency
of th
e
ou
tput
pu
lse,
(d
)
th
e
nu
mber
of clo
ck
pu
lses
t
ransferred
t
o
t
he
o
utput,
a
nd
(
e)
t
he
p
ulse
w
idth
.
V
DD
V
DD
V
DD
Reset
Reset
Reset
R
S
Q
V
ref
V
ref
Clk
V
ref
,
V
reset
Clock
output
+
+
+
–
–
–
DD
V
DD
V
DD
Transfer
Reset
Reset