Professional Documents
Culture Documents
Nhận diện khuôn mặt trên Raspberry pi3
Nhận diện khuôn mặt trên Raspberry pi3
MC LC
MC LC..................................................................................................................... 1
DANH MC HNH V................................................................................................3
LI CM N................................................................................................................ 5
LI M U...............................................................................................................6
CHNG 1. KHI QUT V X L NH V BI TON PHT HIN MT
NGI.......................................................................................................................... 9
1.1. Khi qut v x l nh.........................................................................................9
1.1.1. Mt s khi nim c bn...............................................................................9
1.1.2. Mt s vn trong x l nh.....................................................................10
1.1.3. Mt s ng dng trong x l nh................................................................12
1.2. Bi ton pht hin mt ngi.............................................................................13
1.2.1. Gii thiu v bi ton xc nh mt ngi trong nh...................................13
1.2.2. nh ngha bi ton xc nh mt ngi......................................................13
CHNG 2. BI TON NHN DIN MT NGI..............................................14
2.1. Bi ton nhn dng mt ngi...........................................................................14
2.2. Nhng kh khn ca nhn dng khun mt.......................................................14
2.3. Tm quan trng ca bi ton nhn din mt ngi............................................15
2.4. Cc ng dng c trng ca bi ton nhn din mt ngi...............................16
Cc ng dng khc:...............................................................................................17
2.5.Xy dng h thng nhn din mt ngi c trng............................................17
2.6. Mt s phng php nhn din mt ngi........................................................18
2.6.1. Da trn tri thc..........................................................................................19
2.6.2. Hng tip cn da trn c trng khng thay i.....................................22
2.6.3. Hng tip cn da trn so khp mu.........................................................25
2.6.4. Hng tip cn da trn din mo...............................................................28
CHNG 3. C S L THUYT............................................................................35
3.1. Pht hin mt ngi...........................................................................................35
n 2
Trang 1
n 2
Trang 2
n 2
Trang 3
n 2
Trang 4
n 2
Trang 5
Trang 6
n 2
Trang 7
Trang 8
nh c x
l
nh
X l
nh
Kt lun
Hnh 1. Qu trnh x l nh
Tin x
l
Trch
chn c
im
i snh
nhn
dng
Hu x
l
Lu tr
n 2
Trang 9
n 2
Trang 10
Trang 11
n 2
Trang 12
Trang 13
n 2
Trang 14
Trang 15
n 2
Trang 16
nh tnh
Tin x l
n 2
Trch
Trangrt
17c
trng
Nhn din
khun mt
n 2
Trang 18
Trang 19
n 2
Trang 20
(2.1)
Da trn biu hnh chiu ngang, c hai cc tiu a phng khi hai ng
xt qu trnh thay i c ca HI, chnh l cnh bn tri v phi ca hai bn u.
Tng t vi hnh chiu dc VI, cc cc tiu a phng cng cho ta bit v tr ming,
nh mi, v hai mt. Cc c trng ny xc nh khun mt. Hnh 5.a cho mt
v d v cch xc nh nh trn. Cch xc nh ny c t l xc nh chnh xc l
86.5% cho trng hp ch c mt khun mt thng trong nh v hnh nn khng phc
tp. Nu hnh nn phc tp nh hnh 5.b th rt kh tm. Cn nu nh c nhiu khun
mt (hnh 5.c) th s khng xc nh c.
Trang 21
n 2
Trang 22
Hnh 6. Kt cu khun mt
c.Sc mu ca da:
n 2
Trang 23
Hinh 7. Mu sc da mt
d.a c trng:
Gn y c nhiu nghin cu s dng cc c trng ton cc nh: mu da
ngi, kch thc, v hnh dng tm cc ng vin khun mt, ri sau s xc nh
ng vin no l khun mt thng qua dng cc c trng cc b (chi tit) nh: mt,
lng my, mi, ming, v tc. Ty mi tc gi s s dng tp c trng khc nhau.
2.6.3. Hng tip cn da trn so khp mu
Trong so khp mu, cc mu chun ca khun mt (thng l khun mt c
chp thng) s c xc nh trc hoc xc nh cc tham s thng qua mt hm. T
mt nh a vo, tnh cc gi tr tng quan so vi cc mu chun v ng vin
khun mt, mt, mi v ming. Thng qua cc gi tr tng quan ny m cc tc gi
quyt nh c hay khng c tn ti khun mt trong nh. Hng tip cn ny c li th
l rt d ci t, nhng khng hiu qu khi t l, t th, v hnh dng thay i. Nhiu
n 2
Trang 24
Trang 25
Trang 26
Trang 27
Trang 28
Trang 29
Trang 30
n 2
Trang 31
Trang 32
n 2
Trang 33
CHNG 3. C S L THUYT
3.1. Pht hin mt ngi
Hc theo adaboost l mt cch trong hng tip cn da trn din mo, Viola v
Jones dng AdaBoost kt hp cascade xc nh khun mt ngi vi cc c trng
dng Haar wavelet-like. Tc x l kh nhanh v t l chnh xc hn 80% trn nh
xm.
Thut ton hc my Adaboost c pht trin thut ton boosting, do nhm s
trnh by mt cht v thut ton boosting trc khi trnh by v adaboost.
n 2
Trang 34
n 2
Trang 35
n 2
Trang 36
hk (x )= 1nu p k f k ( x ) < pk k
0 nu ng c li Trong :
n 2
Trang 37
1 1
,
2 m 2l
j=
k
Cp nht li trng s:
w t+1, k =
Trong :
Zt
wt ,k e , ht ( x k )= y k
Zt
e , ht ( x k ) y k
t
1 j
1
t = ln (
)
2
j
factor)
4. Strong classifier c xy dng :
T
H ( x )=d u
(
t =1
S khi:
n 2
Trang 38
t ht (x )
Tp cc mu v trng s Bt u hun
Khi
luyn
to tp c
Mu
Mu sai
ng
cb
trp
Xc nh cc c trng trong tng mu, xy dng cc
Cp nht li trng s
Sai
Xc nh ngng
Lutrweak
Chn weak classifier c gi
li bcla
n
ng
H ( x )=du
(
t =1
n 2
Trang 39
t ht (x )
Trang 40
Trang 41
P(x,y)
P ( x , y )=
'
i(x' , y ' )
'
x x, y y
P1
P2
D
P3
P4
RSAT(x,y)
(b)
Trang 42
C
3
(a)
n 2
Trang 43
Fi =
N :=
Nu Fi >Ftarget
N = { s mu sai stage hin ti phn loi sai }.
P = { s mu positive m stage hin ti phn loi dng }
N-1
hitrate = hN
h
1-f
1-f
1-f
falsealarms = fN
1-f
n 2
Trang 44
NON-CLASS
N
Y
N
C
L
A
S
S
Y
I
Trang 45
n 2
Trang 46
NON-CLASS
N
Y
N
C
L
A
S
S
c lng cc c trng
Cu trc phn tng (Cascade of classifier)
S lng ln cc c trng
Chn c trng
C1
C2
Cn
Quyt nh kt qu
Cc hm Haar c bn
Integral Image
n 2
Trang
47 nhanh t nhiu t l
Tnh cc c
trng
nh
gc
Hnh 20. Tng
quan v h thng pht hin mt ngi trong nh s dng Cascade of
classifier
3.2. Nhn din mt ngi
Hai phng php tip cn vi nhn dng khun mt hin nay l: Nhn dng da trn
u im ca phng php:
Phng php ny gn vi cch m con ngi s dng nhn bit khun
mt .
Vi vic xc nh c tnh v cc mi quan h, phng php ny c th
cho kt qu tt trong cc trng hp nh c nhiu nhiu, nh b nghing,
b xoay, nh sng thay i.
Nhc im ca phng php:
Vic mt xc nh mt lc nhiu c tnh v cc mi quan h i hi cc
thut ton phc tp.
Nu nh c phn gii b, cc mi quan h gia cng mt cp c tnh
trn cc khun mt u rt st nhau, iu ny dn n kt qu nhn dng
khng chnh xc. Vi nh c phn gii ln hn th khi lng tnh
ton s rt ln, i hi cao v cu hnh phn cng.
3.2.2. Nhn dng da trn xt ton din khun mt (Appearance Based)
Ni dung chnh ca hng tip cn ny l xem mi nh c kch thc RxC l mt
vec-t trong khng gian RxC chiu. Ta s tm mt khng gian mi c chiu nh hn,
sao cho khi c biu din trong khng gian cc c im chnh ca mt khun
n 2
Trang 48
n 2
Trang 49
u im ca phng php:
LDA mang hu ht cc u im ca phng php PCA, ng thi khc
phc c nhc im c bn ca PCA.
Nhc im ca phng php:
LDA i hi mt khi lng tnh ton rt ln. Hin nay vn cha c cch
tnh nhanh phng php LDA.
LDA cng nhy vi nhiu ging nh PCA, iu ny i hi nhim v tin
x l nh phi c thc hin ky lng.
3.2.3. Ni dung phng php PCA
3.2.3.1. Xy dng phng php PCA
Trong nhn dng mt ngi, khi s dng PCA, ta coi mt nh xm R C pixels l
mt vec-t trong khng gian N = R x C chiu.
Khng gian mi c to ra bi PCA c cu thnh t K vec-t n v c chiu l
N ,N << R C . Mi vec-t c gi l mt Eigenface.
Php bin i:
n 2
Trang 50
n 2
Trang 51
n 2
Trang 52
n 2
Trang 53
USB
Windows
API Driver
Monitor
OpenCV
Pht hin
khun
mt bng
Adabot
Xc thc
Ngi
thn
i snh vi
CSDL bng PCA
n 2
Trang 54
X l u vo:
Chng trnh nhn u vo l webcam, tuy nhin, vic pht hin khun mt c
thc hin trn cc bc nh, do , ta phi chuyn thnh cc nh tnh v x l trn tng
nh tnh. Sau khi c nh u vo ri th s chuyn nh cho giai on x l tip theo,
l pht hin cc khun mt c trong nh.
Lu khun mt vo c s s liu:
Khun mt sau khi c pht hin s c tch ra khi bc nh v lu di dng
nh bitmap vi phn m rng l *.jpg.
Cc khun mt s c tch ra v lu li thnh cc file nh ring r, v c
nh s th t theo tn khun mt.
i snh vi c s d liu:
Sau khi qu trnh lu tr hnh nh vo c s d liu hon tt, h thng tip tc
quay li giai on x l u vo, pht hin khun mt. S dng thut ton PCA i
chiu v so snh gia khun mt hin ti v nhng khun mt ang c trong c s d
liu. Sau PCA s tm ra c t l ging nhau gia hai bn.
n 2
Trang 55
CV
MLL
HighGUI
Cc hm v x
Cc
l thut
nh v
ton
giihc
thut
my,
v th
baogic
gm
Ccmy
cc
hm
tnh
b
vphn
th tc
cm,
lm
phn
vicloi
vi thng
file nh
kv file
CXCORE
Cc cu trc d liu c bn, cu trc XML, cc hm v ha
Trang 56
n 2
Trang 57
Trang 58
n 2
Trang 59
n 2
Trang 60
n 2
Trang 61
n 2
Trang 62
n 2
Trang 63
n 2
Trang 64
Ht
n 2
Trang 65