Information Fusion Based Learning for Frugal Traffic State Sensing

Traffic sensing is a key baseline input for sustainablecities to plan and administer demand-supplymanagement through better road networks, publictransportation, urban policies etc., Humans sensethe environment frugally using a combination ofcomplementary information signals from differentsensors. For example, by viewing and/or hearingtraffic one could identify the state of traffic on theroad. In this paper, we demonstrate a fusion basedlearning approach to classify the traffic states usinglow cost audio and image data analysis using realworld dataset. Road side collected traffic acousticsignals and traffic image snapshots obtained fromfixed camera are used to classify the traffic conditioninto three broad classes viz., Jam, Mediumand Free. The classification is done on f10sec audio,image snapshot in that 10secg data tuple. Weextract traffic relevant features from audio and imagedata to form a composite feature vector. Inparticular, we extract the audio features comprisingMFCC (Mel-Frequency Cepstral Coefficients)classifier based features, honk events and energypeaks. A simple heuristic based image classifier isused, where vehicular density and number of cornerpoints within the road segment are estimated andare used as features for traffic sensing. Finally thecomposite vector is tested for its ability to discriminatethe traffic classes using Decision tree classifier,SVM classifier, Discriminant classifier and Logisticregression based classifier. Information fusion atmultiple levels (audio, image, overall) shows consistentlybetter performance than individual leveldecision making. Low cost sensor fusion based oncomplementary weak classifiers and noisy featuresstill generates high quality results with an overallaccuracy of 93 - 96%.