A method for counting a number of moving objects that cross at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32) in a scene , comprising: making (S02) detections (401-t1, 401-t2, 401-t3, 401-t4, 401-t5, 401-t6, 401-t7) of positions of one or more moving objects in the scene by using data collected by a sensor device (112-1, 112-2, 112-3), tracking (S04) the one or more moving objects in the scene overtime based on the detections (401-t1, 401-t2, 401-t3, 401-t4, 401-t5, 401-t6, 401-t7) to produce one or more corresponding tracks, calculating (S06), for each moving object , a success probability p i that the moving object succeeded to cross the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32) in the scene , and a failure probability 1 - p i that the moving object failed to cross the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32) in the scene , and calculating (S08) an expected value of a number of moving objects that crossed the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32), characterized by each track being described by a time dependent probability density function (402-t1, 402-t2, 402-t3, 402-t4, 402-t5, 402-t6, 402-t7), the success probability of a moving object being calculated by using the time dependent probability density function (402-t1, 402-t2, 402-t3, 402-t4, 402-t5, 402-t6, 402-t7) describing the track of the moving object , and calculating a variance of the number of moving objects that crossed the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32), wherein the expected value is calculated by summing success probabilities p i calculated with respect to the one or more moving objects , and the variance is calculated by summing products p i (1 - p i ) of success and failure probabilities calculated with respect to the one or more moving objects . making (S02) detections (401-t1, 401-t2, 401-t3, 401-t4, 401-t5, 401-t6, 401-t7) of positions of one or more moving objects in the scene by using data collected by a sensor device (112-1, 112-2, 112-3), tracking (S04) the one or more moving objects in the scene overtime based on the detections (401-t1, 401-t2, 401-t3, 401-t4, 401-t5, 401-t6, 401-t7) to produce one or more corresponding tracks, calculating (S06), for each moving object , a success probability p i that the moving object succeeded to cross the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32) in the scene , and a failure probability 1 - p i that the moving object failed to cross the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32) in the scene , and calculating (S08) an expected value of a number of moving objects that crossed the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32), characterized by each track being described by a time dependent probability density function (402-t1, 402-t2, 402-t3, 402-t4, 402-t5, 402-t6, 402-t7), the success probability of a moving object being calculated by using the time dependent probability density function (402-t1, 402-t2, 402-t3, 402-t4, 402-t5, 402-t6, 402-t7) describing the track of the moving object , and calculating a variance of the number of moving objects that crossed the at least one predefined curve (116-1, 116-21,116-22, 116-31, 16-32), wherein the expected value is calculated by summing success probabilities p i calculated with respect to the one or more moving objects , and the variance is calculated by summing products p i (1 - p i ) of success and failure probabilities calculated with respect to the one or more moving objects . <EOS>