Shopping behavior recognition using a language modeling analogy

Automatic understanding and recognition of human shopping behavior has many potential applications, attracting an increasing interest in the marketing domain. The reliability and performance of the automatic recognition system is highly influenced by the adopted theoretical model of behavior. In this work, we address the analogy between human shopping behavior and a natural language. The adopted methodology associates low-level information extracted from video data with semantic information using the proposed behavior language model. Our contribution on the action recognition level consists of proposing a new feature set which fuses Histograms of Optical Flow (HOF) with directional features. On the behavior level we propose combining smoothed bi-grams with the maximum dependency in a chain of conditional probabilities. The experiments are performed on both laboratory and real-life datasets. The introduced behavior language model achieves an accuracy of 87% on the laboratory data and 76% on the real-life dataset, an improvement of 11% and 8% respectively over the baseline model, by incorporating semantic knowledge and capturing correlations between the basic actions.