EK-Net:Real-time Scene Text Detection with Expand Kernel Distance

Recently, scene text detection has received significant attention due to its wide application. However, accurate detection in complex scenes of multiple scales, orientations, and curvature remains a challenge. Numerous detection methods adopt the Vatti clipping (VC) algorithm for multiple-instance training to address the issue of arbitrary-shaped text. Yet we identify several bias results from these approaches called the "shrinked kernel". Specifically, it refers to a decrease in accuracy resulting from an output that overly favors the text kernel. In this paper, we propose a new approach named Expand Kernel Network (EK-Net) with expand kernel distance to compensate for the previous deficiency, which includes three-stages regression to complete instance detection. Moreover, EK-Net not only realize the precise positioning of arbitrary-shaped text, but also achieve a trade-off between performance and speed. Evaluation results demonstrate that EK-Net achieves state-of-the-art or competitive performance compared to other advanced methods, e.g., F-measure of 85.72% at 35.42 FPS on ICDAR 2015, F-measure of 85.75% at 40.13 FPS on CTW1500.

Category Feature Transformer for Semantic Segmentation

Aggregation of multi-stage features has been revealed to play a significant role in semantic segmentation. Unlike previous methods employing point-wise summation or concatenation for feature aggregation, this study proposes the Category Feature Transformer (CFT) that explores the flow of category embedding and transformation among multi-stage features through the prevalent multi-head attention mechanism. CFT learns unified feature embeddings for individual semantic categories from high-level features during each aggregation process and dynamically broadcasts them to high-resolution features. Integrating the proposed CFT into a typical feature pyramid structure exhibits superior performance over a broad range of backbone networks. We conduct extensive experiments on popular semantic segmentation benchmarks. Specifically, the proposed CFT obtains a compelling 55.1% mIoU with greatly reduced model parameters and computations on the challenging ADE20K dataset.

Attention-guided Chained Context Aggregation for Semantic Segmentation

Recent breakthroughs in semantic segmentation methods based on Fully Convolutional Networks (FCNs) have aroused great research interest. One of the critical issues is how to aggregate multi-scale contextual information effectively to obtain reliable results. To address this problem, we propose a novel paradigm called the Chained Context Aggregation Module (CAM). CAM gains features of various spatial scales through chain-connected ladder-style information flows. The features are then guided by Flow Guidance Connections to interact and fuse in a two-stage process, which we refer to as pre-fusion and re-fusion. We further adopt attention models in CAM to productively recombine and select those fused features to refine performance. Based on these developments, we construct the Chained Context Aggregation Network (CANet), which employs a two-step decoder to recover precise spatial details of prediction maps. We conduct extensive experiments on three challenging datasets, including Pascal VOC 2012, CamVid and SUN-RGBD. Results evidence that our CANet achieves state-of-the-art performance. Codes will be available on the publication of this paper.