Multi-Granularity Semantic Collaborative Reasoning Network for Visual Dialog

A visual dialog task entails an agent engaging in a multiple round conversation about an image. Notably, one of the main issues is capturing the semantic associations of multiple inputs, such as the questions, dialog history, and image features. Many of the techniques use a token or a sentence granularity semantic representation of the question and dialog history to model semantic associations; however, they do not perform collaborative modeling, which limits their efficacy. To overcome this limitation, we propose a multi-granularity semantic collaborative reasoning network to properly support a visual dialog. It employs different granularity semantic representations of the question and dialog history to collaboratively identify the relevant information from multiple inputs based on attention mechanisms. Specifically, the proposed method collaboratively reasons the question-related information from the dialog history based on its granular semantic representations. Then, it collaboratively locates the question-related visual objects in the image by leveraging refined question representations. The experimental results conducted on the VisDial v.1.0 dataset verify the effectiveness of the proposed method, showing the improvements of the best normalized discounted cumulative gain score from 59.37 to 60.98 with a single model, from 60.92 to 62.25 with ensemble models, and from 63.15 to 64.13 with performing multitask learning.