As a prerequisite step of scene text reading, scene text detection is known as a challenging task due to natural scene text diversity and variability. Most existing methods either adopt bottom-up sub-text component extraction or focus on top-down text contour regression. From a hybrid perspective, we explore hierarchical text instance-level and component-level representation for arbitrarily-shaped scene text detection. In this work, we propose a novel Hierarchical Graph Reasoning Network (HGR-Net), which consists of a Text Feature Extraction Network (TFEN) and a Text Relation Learner Network (TRLN). TFEN adaptively learns multi-grained text candidates based on shared convolutional feature maps, including instance-level text contours and component-level quadrangles. In TRLN, an inter-text graph is constructed to explore global contextual information with position-awareness between text instances, and an intra-text graph is designed to estimate geometric attributes for establishing component-level linkages. Next, we bridge the cross-feed interaction between instance-level and component-level, and it further achieves hierarchical relational reasoning by learning complementary graph embeddings across levels. Experiments conducted on three publicly available benchmarks SCUT-CTW1500, Total-Text, and ICDAR15 have demonstrated that HGR-Net achieves state-of-the-art performance on arbitrary orientation and arbitrary shape scene text detection.

Document object detection is a challenging task due to layout complexity and object diversity. Most of existing methods mainly focus on vision information, neglecting representative inherent spatial-related relationship among document objects. To capture structural information and contextual dependencies, we propose a novel document object detector based on spatial-related relation and vision (SRRV). It consists of three parts: vision feature extraction network, relation feature aggregation network and result refinement network. Vision feature extraction network enhances information propagation of hierarchical feature pyramid by adopting feature augmentation paths. Then, relation feature aggregation network combines graph construction module and graph learning module. Specifically, graph construction module calculates spatial information from geometric attributes of region proposals to encode relation information, while graph learning module stacks Graph Convolutional Network (GCN) layers to aggregate relation information at global scale. Both the vision and relation features are fed into result refinement network for feature fusion and relational reasoning. Experiments on the PubLayNet, POD and Article Regions datasets demonstrate that spatial relation information improves the performance with better accuracy and more precise bounding box prediction.

The newly developed enhanced hexagonal-based search using point-oriented inner search (EHS-POIS) enormously speeds up hexagon-based search (HS). From a different perspective, an inherent correlation between distortion and spatial direction through statistical analysis is found. Based on the observed distortion distribution, a novel enhanced hexagonal-based search with direction-oriented inner search (EHS-DIOS) is proposed to avoid real distortion calculation and thus reduce high computation. Experimental results show that, the proposed algorithm is faster than EHS-POIS by achieving two times improvement in terms of inner search speed, and as compared with previous works, it makes a better tradeoff between speed and decoded image quality.