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Images and data files of characters and digits drawn on a tablet PC

character-recognition computer-vision handwritten-digits transfer-learning
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Original Data Format
Version mldata
Data (first 10 data points)

This dataset contains hand-printed (Hnd) characters used in the English language (Latin characters and Hindu-Arabic numerals). It contains 62 classes, and 55 samples per class, giving a total of 3410 samples.

The TGZ file contains two main directories:

  • Trg: contains M files (in MatLab format). Each file contains a vector of rows and a vector of columns, together they have the screen coordinates of the datapoints generated by the strokes to draw the characters.

  • Img: contains PNG images of the bitmaps generated from the hand drawn characters. These is the format used in the paper by deCampos et al VISAPP2009.

Each directory contains a set of sub-directories in the format Samplexxx, where xxx is the class label.

This dataset and the experiments present in the paper were done at Microsoft Research India by Teofilo de Campos, with the mentoring support from Manik Varma. Additional SVM and MKL experiments were performed by Rakesh Babu.

We would like to acknowledge the help of several volunteers who annotated this dataset. In particular, we would like to thank Arun, Kavya, Ranjeetha, Riaz and Yuvraj. We would also like to thank Richa Singh and Gopal Srinivasa for developing some of the tools for annotation .

We kindly request that any publication obtained by using this dataset cites our original benchmark paper [deCampos et al VISAPP2009].

  • T. E. deCampos, B. R. Babu and M. Varma; Character Recognition in Natural Images; In Proceedings of the International Conference on Computer Vision Theory and Applications (VISAPP), 2009;

    This paper tackles the problem of recognizing characters in images of natural scenes. In particular, we focus on recognizing characters in situations that would traditionally not be handled well by OCR techniques. We present an annotated database of images containing English and Kannada characters. The database comprises of images of street scenes taken in Bangalore, India using a standard camera. The problem is addressed in an object categorization framework based on a bag-of-visual-words representation. We assess the performance of various features based on nearest neighbour and SVM classification. It is demonstrated that the performance of the proposed method, using as few as 15 training images, can be far superior to that of commercial OCR systems. Furthermore, the method can benefit from synthetically generated training data obviating the need for expensive data collection and annotation.

Data Source
This dataset was captured from 55 volunteers using a tablet PC with the pen thickness set to match the average thickness found in hand painted public information boards.
Measurement Details

Raw trajectories and image bitmaps

Usage Scenario

This dataset was designed for the task of hand drawn character recognition. Please use the lists available with the associated task in order to follow the protocol for experiments.

An alternative usage is for the evaluation of transductive transfer learning methods (a.k.a. unsupervised domain adaptation) by using samples in this dataset as source domain and samples in the Chars74K English img dataset as target domain (or vice-versa).

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by teo on 2012-03-16 13:46
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by teo on 2012-03-16 13:57
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by teo on 2012-03-16 15:23
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by teo on 2012-03-16 15:23
revision 13
by teo on 2012-09-24 20:35

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This project is supported by PASCAL (Pattern Analysis, Statistical Modelling and Computational Learning)