A Two-Stage Conditional Random Field Model Based Framework for Multi-Label Classification

Multi-label classification (MLC) deals with the task of assigning an instance to all its relevant classes. This task becomes challenging in the presence of the label dependencies. The MLC methods that assume label independence do not use the dependencies among labels. We present a two-stage framework which improves the performance of MLC by using label dependencies. In the first stage, a standard MLC method is used to get the confidence scores for different labels. A conditional random field (CRF) is used in the second stage that improves the performance of the first-stage MLC by using the label dependencies among labels. An optimization-based framework is used to learn the structure and parameters of the CRF. Experiments show that the proposed model performs better than the state-of-the-art methods for MLC.