  In this paper we are interested in the problem of image segmentation given
natural language descriptions, i.e. referring expressions. Existing works
tackle this problem by first modeling images and sentences independently and
then segment images by combining these two types of representations. We argue
that learning word-to-image interaction is more native in the sense of jointly
modeling two modalities for the image segmentation task, and we propose
convolutional multimodal LSTM to encode the sequential interactions between
individual words, visual information, and spatial information. We show that our
proposed model outperforms the baseline model on benchmark datasets. In
addition, we analyze the intermediate output of the proposed multimodal LSTM
approach and empirically explain how this approach enforces a more effective
word-to-image interaction.
