Auto-Encoding Scene Graphs for Image Captioning

We propose Scene Graph Auto-Encoder (SGAE) that incorporates the language inductive bias into the encoder-decoder image captioning framework for more human-like captions. Intuitively, we humans use the inductive bias to compose collocations and contextual inference in discourse. For example, when we see the relation `person on bike', it is natural to replace `on' with `ride' and infer `person riding bike on a road' even the `road' is not evident. Therefore, exploiting such bias as a language prior is expected to help the conventional encoder-decoder models less likely overfit to the dataset bias and focus on reasoning. Specifically, we use the scene graph --- a directed graph ($\mathcal{G}$) where an object node is connected by adjective nodes and relationship nodes --- to represent the complex structural layout of both image ($\mathcal{I}$) and sentence ($\mathcal{S}$). In the textual domain, we use SGAE to learn a dictionary ($\mathcal{D}$) that helps to reconstruct sentences in the $\mathcal{S}\rightarrow \mathcal{G} \rightarrow \mathcal{D} \rightarrow \mathcal{S}$ pipeline, where $\mathcal{D}$ encodes the desired language prior; in the vision-language domain, we use the shared $\mathcal{D}$ to guide the encoder-decoder in the $\mathcal{I}\rightarrow \mathcal{G}\rightarrow \mathcal{D} \rightarrow \mathcal{S}$ pipeline. Thanks to the scene graph representation and shared dictionary, the inductive bias is transferred across domains in principle. We validate the effectiveness of SGAE on the challenging MS-COCO image captioning benchmark, e.g., our SGAE-based single-model achieves a new state-of-the-art $127.8$ CIDEr-D on the Karpathy split, and a competitive $125.5$ CIDEr-D (c40) on the official server even compared to other ensemble models

A hierarchical and regional deep learning architecture for image description generation

This research proposes a distinctive deep learning network architecture for image captioning and description generation. Specifically, we propose a hierarchically trained deep network in order to increase the fluidity and descriptive nature of the generated image captions. The proposed deep network consists of initial regional proposal generation and two key stages for image description generation. The initial regional proposal generation is based upon the Region Proposal Network from the Faster R-CNN. This process generates regions of interest that are then used to annotate and classify human and object attributes. The first key stage of the proposed system conducts detailed label description generation for each region of interest. The second stage uses a Recurrent Neural Network (RNN)-based encoder-decoder structure to translate these regional descriptions into a full image description. Especially, the proposed deep network model can label scenes, objects, human and object attributes, simultaneously, which is achieved through multiple individually trained RNNs The empirical results indicate that our work is comparable to existing research and outperforms state-of-the-art existing methods considerably when evaluated with out-of-domain images from the IAPR TC-12 dataset, especially considering that our system is not trained on images from any of the image captioning datasets. When evaluated with several well-known evaluation metrics, the proposed system achieves an improvement of ∼60% at BLEU-1 over existing methods on the IAPR TC-12 dataset. Moreover, compared with related methods, the proposed deep network requires substantially fewer data samples for training, leading to a much-reduced computational cost

A region-based image caption generator with refined descriptions

Describing the content of an image is a challenging task. To enable detailed description, it requires the detection and recognition of objects, people, relationships and associated attributes. Currently, the majority of the existing research relies on holistic techniques, which may lose details relating to important aspects in a scene. In order to deal with such a challenge, we propose a novel region-based deep learning architecture for image description generation. It employs a regional object detector, recurrent neural network (RNN)-based attribute prediction, and an encoder–decoder language generator embedded with two RNNs to produce refined and detailed descriptions of a given image. Most importantly, the proposed system focuses on a local based approach to further improve upon existing holistic methods, which relates specifically to image regions of people and objects in an image. Evaluated with the IAPR TC-12 dataset, the proposed system shows impressive performance and outperforms state-of-the-art methods using various evaluation metrics. In particular, the proposed system shows superiority over existing methods when dealing with cross-domain indoor scene images