To pursue an efficient text assembling process, existing methods detect texts via the shrink-mask expansion strategy. However, the shrinking operation loses the visual features of text margins and confuses the foreground and background difference, which brings intrinsic limitations to recognize text features. We follow this issue and design Text-Pass Filter (TPF) for arbitrary-shaped text detection. It segments the whole text directly, which avoids the intrinsic limitations. It is noteworthy that different from previous whole text region-based methods, TPF can separate adhesive texts naturally without complex decoding or post-processing processes, which makes it possible for real-time text detection. Concretely, we find that the band-pass filter allows through components in a specified band of frequencies, called its passband but blocks components with frequencies above or below this band. It provides a natural idea for extracting whole texts separately. By simulating the band-pass filter, TPF constructs a unique feature-filter pair for each text. In the inference stage, every filter extracts the corresponding matched text by passing its pass-feature and blocking other features. Meanwhile, considering the large aspect ratio problem of ribbon-like texts makes it hard to recognize texts wholly, a Reinforcement Ensemble Unit (REU) is designed to enhance the feature consistency of the same text and to enlarge the filter's recognition field to help recognize whole texts. Furthermore, a Foreground Prior Unit (FPU) is introduced to encourage TPF to discriminate the difference between the foreground and background, which improves the feature-filter pair quality. Experiments demonstrate the effectiveness of REU and FPU while showing the TPF's superiority.

Most existing traffic sign-related works are dedicated to detecting and recognizing part of traffic signs separately, which fails to analyze the global semantic logic among signs and may convey inaccurate traffic instruction information. Following the above issues, we propose a traffic sign interpretation (TSI) task, which aims to interpret global semantic interrelated traffic signs (e.g., driving instruction-related texts, symbols, and guide panels) into a natural language for providing complete traffic instruction support to autonomous or assistant driving. Meanwhile, considering the lack of an effective framework for the proposed TSI task in existing works, we design a multi-task learning architecture (TSI-arch) to detect and recognize various traffic signs with drastic changes in sizes and aspect ratios. Meanwhile interpreting these signs into a natural language like a human according to Chinese design criteria of road traffic signs. Furthermore, the absence of a public TSI available dataset prompts us to build a traffic sign interpretation dataset, namely TSI-CN. The dataset consists of real road scene images, which are captured from the highway and the urban way in China from a driver’s perspective. It contains rich location labels of texts, symbols, and guide panels, and the corresponding natural language description labels. Experiments on our TSI-CN dataset demonstrate that the TSI task is achievable and the TSI architecture can interpret traffic signs from scenes successfully even if there is a complicated semantic logic among signs.

Recently, segmentation-based text detection methods develop rapidly, which achieve competitive accuracy and detection speed. However, these methods are hard to fit text instances accurately, which leads to the decrease of model performance. Meanwhile, the poor perception of the text center by the boundary pixels further affects the detection accuracy. We follow the issues and design an efficient framework for arbitrary-shaped text detection, which is constructed based on Optimal Kernel Representation (OKR) and Pixel Enhancement Module (PEM). Specifically, OKR is proposed to fit texts with optimal kernels. It erodes texts according to the corresponding geometric characteristics, which is simpler and more accurate compared with previous methods. PEM is used to enhance the perception of boundary pixels to the virtual character centers of text, thus improving the cohesion of the whole instance. Particularly, PEM only participates in the training process, which brings no extra computation costs to inference. Ablation experiments show the effectiveness of OKR and PEM. Comparisons on serveral benchmarks verify that our efficient detector is superior to the existing state-of-the-art (SOTA) methods.