Text information contained in scene images is very helpful for high‐level image understanding. In this study, the authors propose to learn co‐occurrence of local strokes for scene text recognition by using a spatiality embedded dictionary (SED). Unlike spatial pyramid partitioning images into grids to incorporate spatial information, the authors SED associates every codeword with a particular response region and introduces more precise spatial information for robust character recognition. After localised soft coding and max pooling of the first layer, a sparse dictionary is learned to model co‐occurrence of several local strokes, which further improves classification performance. Experimental results on two scene character recognition datasets ICDAR2003 and CHARS74 K demonstrate that their character recognition method outperforms state‐of‐the‐art methods. Besides, competitive word recognition results are also reported for four benchmark word recognition datasets ICDAR2003, ICDAR2011, ICDAR2013 and street view text when combining their character recognition method with a conditional random field language model.

Characters, which are man-made symbols composed of strokes arranged in a certain structure, could provide semantic information and play an indispensable role in our daily life. In this paper, we try to make use of the intrinsic characteristics of characters and explore the stroke and structure-based methods for character recognition. First, we introduce two existing part-based models to recognize characters by detecting the elastic strokelike parts. In order to utilize strokes of various scales, we propose to learn the discriminative multi-scale stroke detector-based representation (DMSDR) for characters. However, the part-based models and DMSDR need to manually label the parts or key points for training. In order to learn the discriminative stroke detectors automatically, we further propose the discriminative spatiality embedded dictionary learning-based representation (DSEDR) for character recognition. We make a comparative study of the performance of the tree-structured model (TSM), mixtures-of-parts TSM, DMSDR, and DSEDR for character recognition on three challenging scene character recognition (SCR) data sets as well as two handwritten digits recognition data sets. A series of experiments is done on these data sets with various experimental setup. The experimental results demonstrate the suitability of stroke detector-based models for recognizing characters with deformations and distortions, especially in the case of limited training samples.

Robust scene-text-extraction system can be used in lots of areas. In this work, we propose to learn co-occurrence of local strokes for robust character recognition by using a spatiality embedded dictionary (SED). Different from spatial pyramid partitioning images into grids to incorporate spatial information, our SED associates every codeword with a particular response region and introduces more precise spatial information for character recognition. After localized soft coding and max pooling of the first layer, a sparse dictionary is learned to model co-occurrence of several local strokes, which further improves classification performance. Experiment on benchmark datasets demonstrates the effectiveness of our method and the results outperform state-of-the-art algorithms.

Text information contained in scene images is very useful for image understanding. In this paper, we propose a high-level representation named stroke bank for scene character recognition. Inspired by the work of object bank, we train stroke detectors and use detectors' maximal output as features. Specifically, we collect training samples for stroke detectors based on labeled key points. We also propose to restrict classification areas of each stroke detector to particular local regions, which alleviates computation burden and retains discrimination power at the same time. Experiments on benchmark datasets demonstrate the effectiveness of our method and the results outperform state-of-the-art algorithms.

Scene text recognition has inspired great interests from the computer vision community in recent years. In this paper, we propose a novel scene text-recognition method integrating structure-guided character detection and linguistic knowledge. We use part-based tree structure to model each category of characters so as to detect and recognize characters simultaneously. Since the character models make use of both the local appearance and global structure informations, the detection results are more reliable. For word recognition, we combine the detection scores and language model into the posterior probability of character sequence from the Bayesian decision view. The final word-recognition result is obtained by maximizing the character sequence posterior probability via Viterbi algorithm. Experimental results on a range of challenging public data sets (ICDAR 2003, ICDAR 2011, SVT) demonstrate that the proposed method achieves state-of-the-art performance both for character detection and word recognition.

Scene text recognition has inspired great interests from the computer vision community in recent years. In this paper, we propose a novel scene text recognition method using part-based tree-structured character detection. Different from conventional multi-scale sliding window character detection strategy, which does not make use of the character-specific structure information, we use part-based tree-structure to model each type of character so as to detect and recognize the characters at the same time. While for word recognition, we build a Conditional Random Field model on the potential character locations to incorporate the detection scores, spatial constraints and linguistic knowledge into one framework. The final word recognition result is obtained by minimizing the cost function defined on the random field. Experimental results on a range of challenging public datasets (ICDAR 2003, ICDAR 2011, SVT) demonstrate that the proposed method outperforms state-of-the-art methods significantly both for character detection and word recognition.

Detecting text in scene images is very challenging due to complex backgrounds, various fonts and different illumination conditions. Without prior knowledge, a detector previously trained using lots of samples still perform badly on a test image because of the disparities in distributions between the training samples and the testing ones. In this paper, we propose to adapt a pre-trained generic scene text detector towards new scenes by transfer learning. In particular, we choose cascade Adaboost as the detector style and try to re-weight pre-selected features according to their abilities to classify high confidence samples. The proposed adaptation mechanism has been evaluated on ICDAR 2011 scene text detection competition dataset and the encouraging experiments results can be compared with the latest published algorithms.