This paper describes a novel method for tracking customers using images taken from video-surveillance cameras. This system analyzes the number of customers and their motions through the aisles of big-box stores (supermarkets) in real-time. The originality of our approach is based on the study of the blobs properties for managing the splitting/merging issues using a mathematical morphology operator. In the order hand, in order to manage a high number of customers in real-time, we combine the advantage of two tracking algorithms.