Feature Set Search Space for FuzzyBoost Learning

Abstract

This paper presents a novel approach to the weak classifier selection based on the GentleBoost framework, based on sharing a set of features at each round. We explore the use of linear dimensionality reduction methods to guide the search for features that share some properties, such as correlations and discriminative properties. We add this feature set as a new parameter of the decision stump, which turns the single branch selection of the classic stump into a fuzzy decision that weights the contribution of both branches. The weights of each branch act as a confidence measure based on the feature set characteristics, which increases the accuracy and robustness to data perturbations. We propose an algorithm that consider the similarities between the weights provided by three linear mapping algorithms: PCA, LDA and MMLMNN [14]. We propose to analyze the row vectors of the linear mapping, grouping vector components with very similar values. Then, the created groups are the inputs of the FuzzyBoost algorithm. This search procedure generalizes the previous temporal FuzzyBoost [10] to any type of features. We present results in features with spatial support (images) and spatio-temporal support (videos), showing the generalization properties of the FuzzyBoost algorithm in other scenarios.

This work was supported by FCT (ISR/IST plurianual funding through the PIDDAC Program) and partially funded by EU Project First-MM (FP7-ICT-248258) and EU Project HANDLE (FP7-ICT-231640).