T^p chi Tin Jipc v^ Diiu khiSn hQC, T.27, S.3 (2011), 275-282 T6 HCfP DLTCJNG FO VA VTLN CHO NHAN DANG TEN TIENG VIET NGO H O A N G H U Y Viin Cdng nghi thdng tin, Viin Khoa hoc vd Cdng nghi Viet Nam Tdm tat Bai bdo de xuit va thii nghiem higu iing cua td hgp ddc trung FO va chuan hda dai bd phdn cau dm (VTLN, vocal tract length normalisation) dl nang cao chit lUdng nhdn dang tilng tdn tilng Vi$t md hinh nhdn d^mg tilng ndi phdt dm lign tuc dua tren HMM Cac kit qua thii nghigm chiing td he nhdn dang tieng ndi dgc ldp ngUdi ndi vdi ddc trung tieng ndi dua trgn dudng FO va ddc trimg MFCC bien doi theo VTLN cho cdc tap tgn rigng cd trung ldp vl dm tilt vd tut Id khd cao, da chudn hda tot biln thign tan so cua ngudi ndi mdi vd cai tien dUdc kit qua nhan dang Abstract This paper presents a study and experiment on combination effect of FO feature and vocal tract length normalisation (VTLN) to improve the HMM-based continuous speech recognition system performance for proper Vietnamese name sets Our experimental results on the recognizer, independent speaker with speech feature based on FO contour and MFCC warped by VTLN for an university name set that has high duplicaton of syllables and words, already well normalized frequency variation of new speakers and improved the recognition performance Tiit khoa FO, formant, VTLN, MFCC, ML, hieu chinh t i n so, dgc lap ngUdi ndi, dieu M d DAU Nghign ciiu cac anh hudng ciia hien tUdng ngdn dieu tilng Viet nhu dieu, cac tan s6 formant vd trUdng dm tilt cac he thdng nhan dang tilng Vigt Id mgt van d^ thilt yeu nhung hien tai It dUdc d l cap tdi cdc cdng trinh nghign ciiu ve xii ly dm tilng Vigt Cac he thdng nhdn dang tilng Viet dUa tren HMM thudng dUa trgn ddc truttig chudn MFCC va quy trinh huin luyen, nhdn dang theo thudt todn sau: Khi ling dumg thudt todn nhdn dang HMM trgn cho vi^c nhan dang tilng ndi lien tuc khdng phu thudc ngUdi ndi, he thdng thudng suy giam dd chfnh xac vdi nhiing ngUdi ndi cd gigng ndi khdng phu hdp vdi nhiing mdu gigng dUdc sut dung di huin luygn md hinh HMM Mgt so nghign cihi gan day da khao sat dudng dieu tilng Viet ngii canh d l nhan dang didu va cai tien kit qua nhdn dang tut vd can tilng Viet [7,8,10,12] Cac tiep can chii yeu vdn ghep true tilp dac tnmg dieu vdo cdc kilu dac tritog tilng ndi nhu MFCC, PLP [10,12] Cd mgt tilp can khdc sut dung gid tri dudng FO, cac tan so 276 NGO HOANC! HUY Bang Thudt todn nhan d9,ng tilng ndi dua trgn HMM vdi ddc trimg MFCC Bifdc 1: X;u- dinh day trying th^i toi xin b^ng thu^t toan Nitcrbi: Nh9,n dijing vdi HMM Dilu vk) gdni T frame ck: d$c trUng MFCC Giii ma theo Viterbi d^ xk: dinh t^p nhan vk day trying th4i t6i Uu ijng vdi bO tham so S mo hinh HMM da cho: Hulm luy^u HMM D^u vk) g6m T frame rir A^ tnfng MFCC ({5,},'=,) -