Fire Detection Algorithms Using Multimodal ... - Bilkent University

CHAPTER 3. FLAME DETECTION IN INFRA-RED (IR) VIDEO 41ratio of the wavelet domain energy to the energy of the low-band signal is a goodindicator of a fire region. This ratio is defined as∑ρ = ∑ l |w[l]|l |c[l]| (3.3)The likelihood of the moving region to be a fire region is highly correlated with theparameter ρ. Higher the value of ρ, higher the probability of the region belongingto flame regions.15(a) Fire Contour Wavelet Coefs.10|w|50805 10 15 20 25 30index n(b) Fire Contour Low−band Coefs.60|c|402005 10 15 20 25 30index nFigure 3.4: The absolute values of a) high-band (wavelet) and b) low-band coefficientsfor the fire region.A threshold ρ T for ρ was experimentally estimated off-line. During real-timeanalysis, regions for which ρ > ρ T are first determined. Such regions are possiblefire regions. In order not to miss any fire region, a low threshold value for ρ Tis selected. Therefore, temporal flicker analysis should be carried out in these