Bi tp ln x l nh Gii thiu qua ti ti 7 : Tm hiu v cc php lc s ,
kho st v lp trnh th nghim cc ng dng ca php lc trn min tn s vi x l
nh mu . Gio vin hng dn: Nguyn Th Hong Lan Nhm sinh vin thc hin :
Nguyn Trung Giang Trn c nh L Tr Dng
Li ni u X l nh ang l mt lnh vc c quan tm v tr thnh mt phn rt
quan trng trng , lin quan n nhiu nghnh khc nh : h thng tin hc , l
thuyt thng tin , l thuyt thng k , tr tu nhn to , nhn dng . y l mt
mn khoa hc tng i mi m so vi nhiu nghnh khoa hc khc . N gm nhiu qu
trnh lin tc . u tin l thu nhn nh t camera , v tinh hay cc b cm ng ,
Tn hiu ly vo s c s ha thnh tn hiu s v chuyn sang giai on x l , phn
tch hay lu tr li . Trong qu trnh hc , chng em c bit hng th vi cc
phng php lc s x l nh . Chnh v vy nhm em chn ti : " Tm hiu v cc php
lc s , kho st v lp trnh th nghim cc ng dng ca php lc trn min tn s
vi x l nh mu " y l mt ti rt hay, c bit to nn nhiu nh vi cc mc ch ca
ngi dng . Chng em tm kim v hc hi t c v t ti liu rt nhiu cng vi qu
trnh xy dng ng dng , chng em rt ra c rt nhiu kinh nghim thc t cng
nh kin thc su hn v mn hc , c th tr li c nhng thc mc t lu . Tuy nhin
do thi gian lm bi tp ln khng c nhiu , cng cha c nhiu kinh nghim ,
ti liu y v lnh vc ny , nn ti ca chng em kh c th trnh khi thiu xt ,
nhng cng t c thng li ban u . Chng em xin cm n c hng dn gip chng em
hon thnh bn bo co ny. Em xin chn thnh cm n .
Nhm sinh vin : Nguyn Trung Giang 20070911 L Tr Dng 20070553Trn c
nh 20073580
Mc lc
Phn I : Tm hiu v cc php lc s1. Khi qut v php lc nh 2. Cc b lc s
2.1.nh ngha v m hnh 2.2.Phn loi b lc - B lc c p ng xung hu hn FIR-
B lc c p ng xung v hn IIR2.3.Cc b lc s thng dng - B lc trung bnh -
B lc thng thp- B lc Laplace- B lc thng cao
Phn II : Kho st v xy dng ng dng cc php lc trn min tn s 1. C s l
thuyt Hn ch ca x l trn min khng gian tng x l trn min tn s Tnh ton
chi tit 2. Cc b lc 2.1. Lc thng thp-Lc tn s thp Idea- Lc tn s thp
Gauss- Lc tn s thp Butterworth 2.2. Lc thng cao -Lc thng cao t lc
thng -Lc tn s thp Idea- Lc tn s thp Gauss- Lc tn s thp
Butterworth
3. Xy dng ng dng
Phn I : Tm hiu v cc php lc s 1. Khi qut v php lc nh Php lc nh c
s dng nhiu trong x l nh , c dng trong gim nhiu , lm nt nh , cng nh
trong pht hin cnh , bin nh Cc php lc nh ch yu c s dng ngn chn cc tn
s cao trong hnh nh , nh lm mn nh hay tn s thp nh pht hin cnh trong
hnh nh . Cc b lc c th chia lm 2 loi theo php ton : lc tuyn tnh v lc
phi tuyn. Php lc tuyn tnh l cc php lc c bn cht l lc tn s nh lc
trung bnh, lc thng thp, lc thng cao, lc o hm. Ngc li cc php lc phi
tuyn bao gm lc trung v, lc ng hnh, lc vi k lng ging gn nht, lc hng
r . Cc php lc nh u s dng cch x l cc b, tc l im nh u ra ch chu nh
hng ca 1 s im nh ln cn theo k thut mt n. Ngi ta cng s dng php nhn
chp ri rc thc hin b lc.
2.1 . nh ngha v m hnh Mt hnh nh c th c lc trong min tn s hoc
trong min khng gian. Trong k thut lc min khng gian ta s dng mt mt n
, t hp im nh t nh hng ca cc im ln cn. Trong min khng gian ta s dng
php nhn chp tn hiu nh u vo vi b lc s : Y (m,n ) = H(k,l ) * X(m,n )
Vi K*L
