한소진동학회논집 제 21  제 3 호, pp. 212~219, 2011. DOI : 10.5050/KSNVE.2011.21.3.212 212/한국소음진동공학회논문집/제 21  제 3 호, 2011년 가청 주파수대 음장 변화 측정 기반 침입 감지 기술 Intrusion Detection Based on the Sound Field Variation of Audible Frequency Band 이 성 규† ․ 박 강 호* ․ 양 우 석* ․ 김 종 대* ․ 김 대 성** ․ 김 기 현** ․ 왕 세 명** Sung Q Lee, Kang-Ho Park, Woo Seok Yang, Jong Dae Kim, Daesung Kim, Kihyun Kim and Semyung Wang (2010년 10 4 접수 ; 2011년 2 1 심사완료) Key Words : Security(보안), Audio Frequency(가청 향), Sound Field Variation( 변화) ABSTRACT In this paper, intrusion detection technique based on the sound field variation of audio frequency in the security space is proposed. The sound field formed by sound source can be detected with the micro- phone when the obstacle or intruder is positioned. The sound field variation due to the intruder is mainly caused by the interference of audio wave. With the help of numerical simulation of sound field for- mations, the increase or decrease of sound pressure level is analyzed not only by the obstacle, but also by the intruder. Even the microphone is positioned behind the source, sound pressure level can be in- creased or decreased due to the interference of sound wave. Frequency response test is performed with Gaussian white noise signal to get the whole frequency response from 0 to half of sampling frequency. There are three security cases. Case 1 is the situation of empty space with and without intruder, case 2 is the situation of blocking obstacle with and without intruder, and case 3 is the situation of side block- ing obstacle with and without intruder. At each case, the frequency response is obtained first at the se- curity space without intruder, and second with intruder. From the experiment, intruder size of diameter of 50 cm pillar can be successfully detected with the proposed technique. Moreover, the case 2 and case 3 bring about bigger sound field variation. It means that the proposed technique have the potential of more credible security guarantee in real situation. * 1. 서 론 최근 안전 협하는 상황 증가하 보안식 † 신저 ; 정회, 한전통신연 E-mail : Hermann@etri.re.kr Tel : (042)860-1142, Fax : (042)860-5608 * 한전통신연 ** 정회 , 주학기술 #  논 부는 2010년 추 소진동 학술대회에서 발표되었 . 및 기술 첨단화로 말미암아 보안시 그 규모 가 확대되어가 다. 보안기술 사람 직/간접 적로 필요로 되는 기술에서 진보하여 동 비/  시스템로 진화를 속하 다 (1) . 보안시스템에 사용되는 센서는 그 기능에 따라 다양하지만, 센서마다 동리와 단점 달라 상호 보완적 역할 분배를 통해서 신뢰성 는 보 안시스템 축하는 것 바람직하다. 건 내   감지하는 기술로 대표적 기술 영상센서, 적외선 센서, 마크로브센서, 레더센서 등