PROBLEM TO BE SOLVED: To provide a size and cost enough to be widely installed because of a simple structure and simple treatment, and also immediately specify a specific substance such as an ethyl alcohol.SOLUTION: An imaging control part 40 stores signal data L1 and L2, which are measured by selectively transmitting infrared rays of absorption wavelength bands &lambda1 and &lambda2 containing the absorption wavelength of the specific substance from a subject through a wavelength variable filter 14 to form them into images on an infrared camera 12, in a memory 24 and also stores signal data L3, which is obtained by measuring infrared rays of a reference wavelength band (L3) containing a wavelength not being the absorption wavelength of the specific substance from the subject, in the memory 24. A calculation part 42 calculates the degree of probability of the specific substance as the angle &theta formed by the vector of the measured data (L1, L2 and L3) stored in the memory 24 and the vector of the reference data (R1, R2 and R3) preliminarily stored in the memory. A decision part 44 determines the detection of the specific substance when the degree of probability of the specific substance is a predetermined threshold or below.COPYRIGHT: (C)2010,JPO&INPIT【課題】簡便な構造と処理により、広く設置可能な大きさと価格をもち、エチルアルコール等の物質の特定を即時になし得ることを可能とする。【解決手段】撮像制御部40は、被写体からの特定物質の吸収波長を含む吸収波長帯域λ1,λ2の赤外光を波長可変フィルタ14により選択的に透過させて赤外線カメラ12に結像して測定した信号データL1,L2をメモリ24に記憶し、また、被写体からの特定物質の吸収波長ではない波長を含む参照波長帯域(λ3)の赤外光を同様に測定して信号データL3をメモリ24に記憶する。計算部42はメモリ24に記憶された測定データ(L1,L2,L3)のベクトルと、メモリに予め記憶された基準データ(R1,R2,R3)のベクトルのなす角θとして特定物質の確率度を算出する。判定部44は特定物質の確率度が所定の閾値以下の場合に特定物質の検出を判定する。【選択図】図1
