Online Learning for Multimodal Data Fusion with Application to Object Recognition

We consider online multimodal data fusion, where the goal is to combine information from multiple modes to identify an element in a large dictionary. We address this problem in the context of object recognition by focusing on tactile sensing as one of the modes. Using a tactile glove with seven sensors, various individuals grasp different objects to obtain 7-D time series, where each component represents the pressure sequence applied to one sensor. The pressure data of all objects is stored in a dictionary as a reference. The objective is to match a streaming vector time series from grasping an unknown object to a dictionary object. We propose an algorithm that may start with prior knowledge provided by other modes. Receiving pressure data sequentially, the algorithm uses a dissimilarity metric to modify the prior and form a probability distribution over the dictionary. When the dictionary objects are dissimilar in shape, we empirically show that our algorithm recognize the unknown object even with a uniform prior. If there exists a similar object to the unknown object in the dictionary, our algorithm needs the prior from other modes to detect the unknown object. Notably, our algorithm maintains a similar performance to standard offline classification techniques, such as support vector machine, with a significantly lower computational time.