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EC
E/O
PT
I533 Digital Im
age Processing class notes 288 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
sto
rag
e v
ers
us tra
nsm
issio
n a
pp
lica
tion
s
sto
rag
e v
ers
us tra
nsm
issio
n a
pp
lica
tion
s
sou
rce
ima
ge
sou
rce c
od
er
sou
rce d
ecod
er sto
rag
e
retrie
ved
ima
ge
sou
rce
ima
ge
sou
rce c
od
er
sou
rce d
ecod
er
retrie
ved
ima
ge
ch
an
nel c
od
er
ch
an
nel d
ecod
er
ch
an
nel
Motiv
atio
n
•La
rge a
mou
nt o
f da
ta in
ima
ges
Colo
r vid
eo: 2
00
Mb
/sec
La
nd
sa
t TM m
ultis
pectra
l sa
tellite
ima
ge: 2
00
MB
•H
igh
pote
ntia
l for c
om
pre
ssio
n
Red
un
da
ncy (a
ka
corre
latio
n) in
ima
ges – s
pa
tial, te
mp
ora
l, sp
ectra
l
EC
E/O
PT
I533 Digital Im
age Processing class notes 289 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
Join
t pro
ba
bility
plo
ts (s
ca
tterg
ram
s) b
etw
een
p
ixels
with
giv
en
horiz
on
tal s
pa
cin
g
∆ =
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
•H
igh
corre
latio
n fo
r clo
se
neig
hb
ors
•A
s p
ixel s
ep
ara
tion
in
cre
ases, c
orre
latio
n
decre
ases
EC
E/O
PT
I533 Digital Im
age Processing class notes 290 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
Lossy c
od
ing
•Som
e a
ccep
tab
le lo
ss o
f da
ta, w
ithou
t loss o
f “in
form
atio
n”
•Erro
r mea
su
res
Mea
n S
qu
are
Erro
r
Root M
ea
n S
qu
are
Erro
r
Norm
aliz
ed
Mea
n S
qu
are
Erro
r
Sig
na
l-to-N
ois
e R
atio
Pea
k-to
-pea
k S
NR
•Pro
ble
ms
Erro
r mea
su
res d
on
’t em
ph
asiz
e v
isu
ally
imp
orta
nt fe
atu
res s
uch
as c
on
trast e
dg
es
• C
an
imp
rove c
orre
latio
n o
f an
y o
f these e
rror m
ea
su
res w
ith v
isu
al q
ua
lity b
y re
stric
ting
to
“ed
ge p
ixels
” o
nly
How
to d
efin
e a
nd
qu
an
tify “
ima
ge q
ua
lity?”
MSE
DN
()
Variance
f̂f
–(
)=
RM
SED
N(
)M
SE
=
NM
SE%(
)100
MSE
()
Variance
⁄f()
=
SNR
dB(
)10
100N
MSE
⁄(
)log
=
PSN
RdB
()
10fm
axfm
in–
() 2
MSE
⁄[
]log
=
EC
E/O
PT
I533 Digital Im
age Processing class notes 291 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
exa
mp
le w
ith JP
EG c
od
ing
1/8
1/1
6
1/3
2
NM
SE =
0.1
6%
NM
SE =
0.4
2%
NM
SE =
1.0
5%
RM
SE =
7.3
7 D
N
RM
SE =
4.6
3 D
N
RM
SE =
2.9
1 D
N
SN
R =
27
.9d
B
SN
R =
23
.8d
B
SN
R =
19
.8d
dB
EC
E/O
PT
I533 Digital Im
age Processing class notes 292 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
Ru
n-L
en
gth
Cod
ing
•Sim
ple
, ima
ge d
om
ain
, lossy
com
pre
ssio
n a
lgorith
m
•Exp
loits
neig
hb
orin
g p
ixel
corre
latio
n, lin
e-b
y-lin
e
Work
s b
est fo
r sim
ple
, low
-freq
uen
cy
con
ten
t, nea
r-bin
ary
ima
ges, e
.g. fa
xes
•D
N th
resh
old
con
trols
qu
ality
loss
an
d c
om
pre
ssio
n ra
te
•Look fo
r “ru
ns”
con
tigu
ou
s p
ixels
with
sim
ilar v
alu
es (w
ithin
th
resh
old
of s
tartin
g p
ixel v
alu
e)
•Cod
e s
tartin
g p
ixel v
alu
e (Q
bits
) a
nd
len
gth
of lin
e (≤
log
N/lo
g2
b
its)
typ
ica
l beh
avio
r (ima
ge d
ep
en
den
t)
T
compression ratio
T
number of runs
T
average runlength 0 00
“intrinsic” runlength
EC
E/O
PT
I533 Digital Im
age Processing class notes 293 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
Lossle
ss C
od
ing
•N
o d
ata
loss
•M
inim
al c
om
pre
ssio
n (ty
pic
ally
2:1
)
•Exa
mp
le a
lgorith
ms
Ru
n-L
en
gth
(with
zero
thre
sh
old
)
Lem
pel-Z
iv-W
els
h (L
ZW
)
Hu
ffma
n C
od
ing
EC
E/O
PT
I533 Digital Im
age Processing class notes 294 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
Com
pon
en
ts o
f sou
rce c
od
er
•D
ata
tran
sfo
rma
tion
wa
vefo
rm c
od
er
tran
sfo
rm c
od
er
ima
ge m
od
el c
od
er
•Q
ua
ntiz
atio
n
bits
, tran
sfo
rm c
oeffic
ien
ts, o
r mod
el p
ara
mete
rs
•Cod
ew
ord
Assig
nm
en
t
un
iqu
e b
it strin
g fo
r ea
ch
qu
an
tized
pa
ram
ete
r
EC
E/O
PT
I533 Digital Im
age Processing class notes 295 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
Wa
vefo
rm C
od
ing
•Pu
lse C
od
e M
od
ula
tion
(PCM
)
Ima
ge in
ten
sity
qu
an
tized
by u
nifo
rm
qu
an
tizer
At lo
w b
it rate
s (ty
pic
ally
less th
an
4 b
its/
pix
el), q
ua
ntiz
atio
n n
ois
e a
pp
ea
rs a
s
fals
e c
on
tou
rs in
are
as o
f low
inte
nsity
slo
pe
16 levels
8 levels
4 levels
EC
E/O
PT
I533 Digital Im
age Processing class notes 296 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
Exa
mp
le 2
-bit u
nifo
rm q
ua
ntiz
er
3∆/2
−3
∆/2
∆/2
−∆/2
+∆−∆
bits
00
01
10
11
in
ou
t
∆
=1
MSE =
0.0
62
8
in codew
ordout
error
1.211
1.5-0.3
1.511
1.50
-200
-1.5-0.5
-0.501
-0.50
0.510
0.50
0.610
0.50.1
-0.7501
-0.5-0.25
1.211
1.5-0.3
Alte
rna
te re
pre
sen
tatio
n:
−3
∆/2
−∆/2
∆/2
3∆/2
+∆−∆
bits
00
01
10
11
mid
-rise u
nifo
rm q
ua
ntiz
er
mid
-trea
d u
nifo
rm q
ua
ntiz
er
−∆/2
∆/2
3∆/2
+∆−∆
bits
00
00
10
10
01
01
−3
∆/2
0
00
1
EC
E/O
PT
I533 Digital Im
age Processing class notes 297 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
•PCM
with
Non
un
iform
Qu
an
tiza
tion
Assig
n q
ua
ntiz
atio
n le
vels
accord
ing
to im
ag
e in
ten
sity
dis
tribu
tion
Sm
all im
pro
vem
en
t for ty
pic
al im
ag
es
• D
ep
en
ds o
n n
on
un
iform
ity o
f ima
ge h
isto
gra
m
For e
xa
mp
le, u
se C
DF a
s n
on
linea
r tran
sfo
rm, i.e
. his
tog
ram
eq
ua
liza
tion
• A
ssig
ns m
ore
levels
wh
ere
there
are
more
pix
els
sou
rce
ima
ge
non
linea
rcod
ed
ima
ge
un
iform
PCM
tran
sfo
rmn
on
linea
rtra
nsfo
rm-1
EC
E/O
PT
I533 Digital Im
age Processing class notes 298 D
r. Robert A
. Schowengerdt 2003
IM
AGE C
OD
ING
PCM
with
Pseu
do-n
ois
e
•A
dd
ran
dom
nois
e to
ima
ge b
efo
re P
CM
•Su
btra
ct s
am
e ra
nd
om
nois
e a
fter P
CM
•R
em
oves s
pa
tial c
orre
latio
n o
f qu
an
tiza
tion
nois
e
sou
rce
ima
ge
decod
ed
ima
ge
un
iform
PCM
η(m
,n)
EC
E/O
PT
I533 Digital Im
age Processing class notes 299 D
r. Robert A
. Schowengerdt 2003
IMA
GE C
OD
ING
exa
mp
le w
ith 3
bits
/pix
el a
nd
un
iform
ran
dom
nois
e
un
iform
min
us n
ois
e
ad
d n
ois
ePCM
(3b
its/p
ixel)
PCM
(3b
its/p
ixel)
EC
E/O
PT
I533 Digital Im
age Processing class notes 300 D
r. Robert A
. Schowengerdt 2003
IMA
GE C
OD
ING
Delta
Mod
ula
tion
•Cod
e d
iffere
nce o
f neig
hb
orin
g
pix
els
with
1 b
it
Assu
me s
om
e “
sca
n” p
atte
rn in
ima
ge
•R
ed
uces s
pa
tial c
orre
latio
n b
efo
re
cod
ing
exa
mp
le ro
w-b
y-ro
w im
ag
e s
ca
n
pa
ttern
EC
E/O
PT
I533 Digital Im
age Processing class notes 301 D
r. Robert A
. Schowengerdt 2003
IMA
GE C
OD
ING
Exa
mp
le
ima
ge:
67
88
59
10
8
68
97
79
11
9
diffe
ren
ces:
61
10
-4-1
20
12
1-2
-2-2
22
diffe
ren
ce ≥
0: c
od
ew
ord
= 1
diffe
ren
ce < 0
: cod
ew
ord
= 0
indifference
codeword
outerror
66
11
-0.3
71
17
0
81
18
-0.5
80
19
0
102
10
9-1
00.1
5-4
0-0.25
61
1-0.3
82
1
91
1
7-2
0
92
1
112
1
9-2
0
7-2
0
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