Information Fusion Methodsfor Outdoor Alarm Systems

Barna ComelAurel Vlaicu University Arad

Romania

Abstract: In this paper is presented an information fusionmethod used in surveillance systems, formed with video camerasand PIR detectors, for estimating the location of an intrusionobject and producing an alarm signal. This method has a soundbackground based on heuristic and fuzzy relation andgranularity assumption, which is suitable for outdoor alarmsystem, where the possibility of false alarms is very high.

Keywords: heuristic fusion, fuzzy functions, reinforceinformation fusion video cameras, PIR detectors

I. INTRODUCTION

In alarm system used today one of the most commonelements is the infrared volumetric motion detection calledPIR detectors [6]. Each of this detector's outputs is a binarysignal provided by a reed relay. So, the information obtainedfrom one sensor is quite limited, indicating the presents or notof an object. In most of cases the alarming signals providedvery limited information that is an intrusion, which isunacceptable for large surveillance areas. A usual device usedin alarm systems is the video surveillance with video cameras.These systems are more accurate but are vulnerable in foggyor darkness conditions. For these reasons an informationfusion between this two types of data permit a better detectionlevel and a reduce number of false alarms. The result obtaineddepends from the fusion method used. In this article will becompared three types of information fusion: a heuristic, afuzzy and a new one called the reinforced fusion between thealarm signals obtained from the video and the PIR

systems RV , RD . It will be concluded that the last of thesemethods is the most suitable to alarm systems.

II. THE HEURISTIC FUSION

The first type of information fusion that will be presentedis the heuristic one. This method can be implementedintroducing different kinds of operators, for example it can beused operations like: the sum, the product, the median, andthe weighted sum. These operations, even if they are simple,produce good results, especially the median one. But, in thiscase we have only two operators, so the median can not beapplied. In [1] was demonstrated that the sum operation is

more reliable that the product, so in our case it will beimplemented the weighted sum operator. Using this method itcan be added flexibility to the operation and permit tounderline the importance of the video and PIR inputs [2]. Butin this case is necessary to determine of two constantsSo, it will be use the relation:

FE =a.RV +b.RD (1)where

a, b are constants, and must satisfied the followingcondition: a+b= and a, be [0, 1],The notations R. , RD represents the outputs from the video,and from the infrared detection systems. The constants canbe determined using numerous methods. In our case weestablish to follow a supervised solution, by using theprevious levels of errors, eV determined for video and EDfor infrared system. Results that the constants a, b areobtained using a normalized relation:

a= -+eV + £D

and b = veV +£D

(2)

Using this fusion method, the fusion result can beimproved based on past experiments, but the system can notreact to the changes on the external conditions. Being anoutdoor alarm system, these changes will appear often, so theerror rate of the heuristic method CE will be significant.

It can be introduced a soft decision model, by using aconfidence level. For determining this, is proposed a relationwhich use the error rate and a threshold OE, that establish an

upper limit for an accepted error. The relation is:

(3)min(20E, E)20E

where PUE is the confidence level of the heuristic method. Itmust be underlined that the value of the threshold is fixedarbitrary, and this is another disadvantage of this method.

1-4244-1148-3/07/$25.00 ©2007 IEEE.

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INES 2007 - 1111 International Conference on Intelligent Engineering Systems - 29 June- I July, 2007 - Budapest, Hungary

IL THE FUZZY FUSIDN

This i-ifDm atbn fusin m ethod use fuzzy results fr-mthe tg o t/pes of del-teion thatm eans that the fusaon resultwIllbe aconfidence level [3]. For detem ing the fusJonmhtbn itw iJllbe usefultD ana:lyze the tA o sysbn s involved[4 ] . So, the video sysbn is baed on lightdetaectn,m eaningthatin ainmess orfDggy conditbns dai sysE is outof use.For ths conditbns is m o-r efficient tD use the inia-eiifform atbn. O n the otherhand, ini hotconditbn the inioedeteia-tn is unreiable, and is usefultD give am o-r significantimportance tD the video i-iDnfo atn. Results, that the tA7oalm sysnE s have a com plan entai m a15lctDn condiiLns.This factcan be used fDr =ating a fusion f nctbn baed onboth confidence levels and the results de-livemd by thedetaectn sysbE s:

poinitofvi-- of advantages dai m ethod is com plan entai tDthe p=Jiously prestad heusticm ethod.

37 .TH E REENFO RC ED FU SID N

The last method of i-ifDimatn fusion betA7een theresults obtained fr-m the tA o t/pes of captoz- is a new onecaDe the mi=fbm-ed fusJon. Because the infDim ation obtainfr-m the vi-deo) can eo is m om signifrat than themfinio atiDn from the inire delE-tecos, the latber w ill onlymi=fbore the conclusion of the fDim er. Thus, onew IAllope-nateon the results obtained fr-m both m ethods in oijertD inc~orderae the unceritaty obtained from the vi-deo) can e-o.The folbw ing aipednsh- w IAllbe openla-:d:

U F==m in,Lu) (7)and

F = UV RV +pJD -RDF

PUV + JUD11 - 1+1 # SV S I

I1 lvl,)U =-1U (La

K(4)

w he-zFF s the fuzzy fusin msltUv p2D c-;r the

confidence levels of the vi-deo and inam sysnms, and

RV /RI) mpsts the m-cultsbbtan from thevideo and the

inare delEycitn sysnE s. It can be uscually detem ined w iththe fo]low ing mhtbn:

JUF 2 (U + PID) (5)

This is the aggmgate-d confidence level of dais infDYm atDnfusion .

in oijertD establii:- thevideo and the inam confidence

levels2UpvU Wp I) II be used the m eam= ent of the e>t-al

condiitns whach have the m ost signifcant influence on thetAo types of delEycitn. For the video sysbn it w I]l bedecsm ined the iat:E? of cu-et changes of light conditonAH a I and the maxi-mum accepted lIghtcondidon AH N 1

and fDr the inoe sysbE i-tw IAllbe detem ined the zate ofcun-et changes of tan pemtua conditDn, and the m axi-m umaccepted light condiitn. The tao confidence levels c-;Li

detem ined usJng the mhtons:

whe-z:

1 ,1~ae the cistances bbtinmed by video),

rsectmely by inare -Ens,-s Sv /SI -ae the est3atp-d

say-aes obtcn,ed by vi-deo, yepectwely by inam nsmsca ,,l (E [O ,1]I arew eigh coeffirients, and K is a no-un alizatkn

factDr and U = l-uv /,UD iS the uncat.nty level of the

video) SySbEM [5]1.Itm ust be obsered that a > ,8 because the esdn atbn

of the sarfaes is 1~accute dn the results obtaned fDrthe distances. C hoosing fDrexan ple

1+ a +,i(

2

itcan msult intD a biggerconfidence in the obtaned result ifa ,flarann all, oritcan incas the degree ofuncenaty ifthe e=-i ofdisSnce and s--ace esLn atbn car signifi=at. In

the end, by applying a oaehld tD the f;nal mcult U Ftheest3maldns can boe acc(eptad or not. For dai method theconfidence levelw Ill re-cult as a oppost of the uncertantylevel:

PC = 1-UFAv7 = m i (L, a) and PUD = m in,aL )

(9)(6)

It can be obsefed tat dais fusiDn aiphdn ism athEm atc =m ilarw ith the w eight aim , but in dais caseis used uncertaty levels. C ompang the results obtamedusng the pnstBd m ethods; itw as ob=vred the lasthad thebest bhvior. This conclusiDn is the result of usnguncenaty levels, which confer a hi-gher generahty of thefusion opemtion.

whe-z the m inim um functoDn is used tD bounder the iatevandation.

Itcan be obs-ved thatd=m ethod iiacttD the changes of theextp=al conditions but the main disadvantage is that of-gnorng the past h2sbr. So, it can be notice that from the

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B. Comel Information Fusion Methods for OutdoorAlarm Systems

V .CONCLUSIDNS

REFERENC ES

infiDim atiDn fusiDn tai-ques c-ii m osdy baed onifnDi i aldn pi-vided by video) can er,s. in dai arbcle, aeem ethods c-;Lr prestBd. in fst case a heustic m ethod is

used, but it re-cults tat changing texifal conditions an;'detcBm inig sJgniiate=-i. The secondm ethod is baedF ona fuzzy mhton. The results obtan with dais fusion c-;-

efLc-ted by the lack i-m pmvEm ent dehivemd by past events.F illy, is peirfDm ed an ifDini atiDn fusion by enfDcing theuncenty degree pmved by the video sysbn with theinfDim aton obtaned fom the infoe delEyctms. Thisope-otn is baed on the pamptbn thatvideo providedinDini atbn is m om signifcat dn that obtaned fom theinhae detac-to-i. This lastm ethod w as proved tD have thebestresults.

[1I] F A Ikoot^JK itJe-r: I'M odified product fu=in", Patt} RecogniXLnLett=<vol23;qr.8 2002

[2 ] C Bama "An A -la SysnE D esin with PJR using Fuzzy SEnmrFusin and G enetic A lgorfn Rrog= T'JE E SO FA 2005 Szeged-Aiadpag.195-199

[3] A BaEirg , W ,Pedrycz, K H ita "Logic-aed genularpmtDt,ping"l 26th Annual Inteatnal C omputer SoftwareCOM PSAC 2002

[4] V Balas, C.Bama. : 'vThe esfinatDn of vegetatn stage ofgne-houseplnts",UAV Juma 12004 pag35 40

[5 ] R .Yager, "A G eneol approach tD he Fusin of Tm preci_eInfD-umatn/,ltmnatknalJbumalofintalligentsybn voL12 1997

[6] -Ted-acal-refe=rcefDrP]RD-gitalSeautyContlosLtd

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