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Holistic versus segmentation-based recognition of handwritten Devanagari conjunct characters: a CNN-based experimental study

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Abstract

Character recognition of the script is the most vital step of Optical Character Recognition and the recognition accuracy directly affects the optical character recognition performance. Recognition of the script is fully achieved when all the components of the script are recognized completely. The conjunct character of the Devanagari script is one such component whose recognition is a challenging task. Researchers are adopting either segmentation-based or segmentation-free (holistic) recognition of these conjunct characters using structural features. This work provides an experimental study to compare between the holistic- and segmentation-based recognition of handwritten Devanagari conjunct characters. We propose a polygonal approximation-based novel segmentation approach that uses structural properties to decompose the conjunct characters of the Devanagari script to its constituent characters. This technique segments the conjunct character from the point where two basic shapes are joined to form the conjunct character and thus, segmentation accuracy is enhanced. Convolutional neural network and convolution neural network-based transfer learning are used for the recognition purpose. Convolutional neural network-Recurrent neural network hybrid architecture is also adopted to simplify the holistic approach and reduce the classification complexity. A comparative study is delineated between the methods on the basis of experiments conducted. The proposed method is observed to provide better results in terms of segmentation and recognition of conjunct characters in comparison to previously reported works.

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Author notes

  1. Deepika Gupta

    Present address: Department of Computer Science and Engineering, Thapar Institute of Engineering and Technology, Patiala, 147004, India

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  1. Department of Computer Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, Dhanbad, 826004, India

    Deepika Gupta & Soumen Bag

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  1. Deepika Gupta
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  2. Soumen Bag
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Correspondence to Soumen Bag.

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Gupta, D., Bag, S. Holistic versus segmentation-based recognition of handwritten Devanagari conjunct characters: a CNN-based experimental study. Neural Comput & Applic 34, 5665–5681 (2022). https://doi.org/10.1007/s00521-021-06672-6

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