关键词: 支持向量机, 多分类, 决策导向非循环图, 主动学习

Abstract: A multi-class active learning approach for image classification is described by using Decision Directed Acyclic Graph Support Vector Machine，featured by rapid decision-making，as basic classifier and the ideas of active learning are combined.This approach is a semi-automatic classification method for image semantics，and can be used to divide images into different categories.In this approach，an active selection strategy based on the level of doubts is presented on the basis of the widely-used method of selecting the closest samples to the dividing hyperplane.This strategy extends the strategy of selecting the closest ones to the SVM dividing hyperplane specified in SVMactive algorithm to multi-class classification，and at the same time，treats odd samples and easily mistaken samples differently.In this way，the interference of noise on classifier is reduced，and the accuracy of classification is increased.

Key words: support vector machine, multi-class classification problem, decision directed acyclic graph, active learning