  Multi-label learning has attracted significant interests in computer vision
recently, finding applications in many vision tasks such as multiple object
recognition and automatic image annotation. Associating multiple labels to a
complex image is very difficult, not only due to the intricacy of describing
the image, but also because of the incompleteness nature of the observed
labels. Existing works on the problem either ignore the label-label and
instance-instance correlations or just assume these correlations are linear and
unstructured. Considering that semantic correlations between images are
actually structured, in this paper we propose to incorporate structured
semantic correlations to solve the missing label problem of multi-label
learning. Specifically, we project images to the semantic space with an
effective semantic descriptor. A semantic graph is then constructed on these
images to capture the structured correlations between them. We utilize the
semantic graph Laplacian as a smooth term in the multi-label learning
formulation to incorporate the structured semantic correlations. Experimental
results demonstrate the effectiveness of the proposed semantic descriptor and
the usefulness of incorporating the structured semantic correlations. We
achieve better results than state-of-the-art multi-label learning methods on
four benchmark datasets.
