OCR for printed Kannada text to machine editable format using database approach (original) (raw)
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A Comprehensive Survey on OCR Techniques for Kannada Script
In modern days, there is a pervasive inclination towards digitization of text documents for the ease of their access and maintenance. Digitized documents can be preserved for the future since this form has a longer shelf life. Optical Character Recognition (OCR) system translates a digitized text document from human readable form to machine editable codes. Many commercial OCRs are available today for documents written in English, Japanese, Chinese , Arabic and a few Indian scripts. Kannada is the official language of Karnataka, which is one of the southern states of India.Development of OCR for Kannada script is an active research area currently. Kannada language consists of a large set of characters, many of which are very similar in structure. This makes the job of developing an OCR for this language several magnitude more complicated than for a language like English. The very fact that research on developing OCRs for Kannada language is very promising and is still emerging necessitated this survey paper. The aim of this paper is to discuss in detail: the peculiarities of the Kannada script, challenges they pose for recognition, techniques reported in the literature, recognition accuracies and a comparison with other OCR systems.
Machine Recognition of Printed Kannada Text
5th International Workshop, DAS 2002 , Proceedings, 2002
This paper presents the design of a full fledged OCR system for printed Kannada text. The machine recognition of Kannada characters is dificult due to similarity in the shapes of different characters, script complexity and non-uniqueness in the representation of diacritics. The document image is subject to line segmentation, word segmentation and zone detection. From the zonal information, base characters, vowel modifiers and consonant conjuncts are separated. Knowledge based approach is employed for recognizing the base characters. Various features are employed for recognising the characters. These include the coefficients of the Discrete Cosine Transform, Discrete Wavelet Transform and Karhunen-Louve Transform. These features are fed to different classifiers. Structural features are used in the subsequent levels to discriminate confused characters. Use of structural features, increases recognition rate from 93% to 98%. Apart from the classical pattern classification technique of nearest neighbour, Artificial Neural Network (ANN) based classifiers like Back Propagation and Radial Basis Function (RBF) Networks have also been studied. The ANN classifiers are trained in supervised mode using the transform features. Highest recognition rate of 99% is obtained with RBF using second level approximation coefficients of Haar wavelets as the features on presegmented base characters.
Lipi Gnani - A Versatile OCR for Documents in any Language Printed in Kannada Script
ArXiv.org, 2019
A Kannada OCR, named Lipi Gnani, has been designed and developed from scratch, with the motivation of it being able to convert printed text or poetry in Kannada script, without any restriction on vocabulary. The training and test sets have been collected from over 35 books published between the period 1970 to 2002, and this includes books written in Halegannada and pages containing Sanskrit slokas written in Kannada script. The coverage of the OCR is nearly complete in the sense that it recognizes all the punctuation marks, special symbols, Indo-Arabic and Kannada numerals and also the interspersed English words. Several minor and major original contributions have been done in developing this OCR at the different processing stages such as binarization, line and character segmentation, recognition and Unicode mapping. This has created a Kannada OCR that performs as good as, and in some cases, better than the Google's Tesseract OCR, as shown by the results. To the knowledge of the authors, this is the maiden report of a complete Kannada OCR, handling all the issues involved. Currently, there is no dictionary based postprocessing, and the obtained results are due solely to the recognition process. Four benchmark test databases containing scanned pages from books in Kannada, Sanskrit, Konkani and Tulu languages, but all of them printed in Kannada script, have been created. The word level recognition accuracy of Lipi Gnani is 4% higher on the Kannada dataset than that of Google's Tesseract OCR, 8% higher on the datasets of Tulu and Sanskrit, and 25% higher on the Konkani dataset.
Sadhana-academy Proceedings in Engineering Sciences, 2007
Optical Character Recognition (OCR) systems have been effectively developed for the recognition of printed characters of non-Indian languages. Efforts are on the way for the development of efficient OCR systems for Indian languages, especially for Kannada, a popular South Indian language. We present in this paper an OCR system developed for the recognition of basic characters (vowels and consonants) in printed Kannada text, which can handle different font sizes and font types. Hu’s invariant moments and Zernike moments that have been progressively used in pattern recognition are used in our system to extract the features of printed Kannada characters. Neural classifiers have been effectively used for the classification of characters based on moment features. An encouraging recognition rate of 96.8% has been obtained. The system methodology can be extended for the recognition of other south Indian languages, especially for Telugu.
Kannada Character Recognition System: A Review
Intensive research has been done on optical character recognition ocr and a large number of articles have been published on this topic during the last few decades. Many commercial OCR systems are now available in the market, but most of these systems work for Roman, Chinese, Japanese and Arabic characters. There are no sufficient number of works on Indian language character recognition especially Kannada script among 12 major scripts in India. This paper presents a review of existing work on printed Kannada script and their results. The characteristics of Kannada script and Kannada Character Recognition System kcr are discussed in detail. Finally fusion at the classifier level is proposed to increase the recognition accuracy.
Recognition of Hindi Character Using OCR-Technology: A Review
International Journal of Advanced Trends in Computer Science and Engineering , 2023
Recognition of character is a technique that enables the transformation of various kinds of scanned papers into an editable, readable, and searchable format. In the last two decades, several researchers and technologists have been continuously working in this field to enhance the rate of accuracy. Recognition of character is classified into printed, handwritten , and characters written at image recognition. Recognition of character is the major area of research in the field of pattern recognition. This paper presents an overview of Hindi character recognition by utilizing the optical character recognition (OCR) technique. We surveyed some major research breakthroughs in character recognition, especially for Hindi characters. This research article focuses to provide a deeper insight into the researchers and technologists working in the field of recognition of Hindi-character.
Optical Character Recognition or OCR is the electronic translation of handwritten, typewritten or printed text into machine translated images. Optical Character Recognition (OCR) is a very important task in Pattern Recognition. Foreign languages, especially English character recognition has been extensively studied by many researches but due to complication of Indian Languages like Hindi ,Punjabi ,teulgu ,malyalam etc. the research work is very limited and constrained. This paper presents the research work related to all Indian languages, various approaches to character recognition along with some applications of character recognition is also discussed in this paper. The aim of this paper is to provide an overview of the research going on in Indian script OCR systems. This survey paper has been felt necessary when the research on OCRs for Indian scripts is still a challenging task. Hence, a brief introduction to the general OCR and typical steps in the development of an OCR are give...
A Complete OCR for Printed Tamil Text
Proc. Tamil Internet 2000 (TI 2000)
A multi-font, multi-size Optical Character Recognizer (OCR) of Tamil Script is developed. The input image to the system is binary and is assumed to contain only text. The skew angle of the document is estimated using a combination of Hough transform and Principal Component Analysis. A multi-rate-signal-processing based algorithm is devised to achieve distortion-free rotation of the binary image during skew correction. Text segmentation is noise-tolerant. The statistics of the line height and the character gap are used to segment the text lines and the words. The images of the words are subjected to morphological closing followed by connected component-based segmentation to separate out the individual symbols. Each segmented symbol is resized to a pre-fixed size and thinned before it is fed to the classifier. A three-level, tree-structured classifier for Tamil script is designed. The net classification accuracy is 99.0%.
Optical Character Recognition (OCR) is a technique, which is used to extract the text from document images and converted into text format. This kind of information retrieval is called as recognition based retrieval hence that it can be edited, searched, stored more efficiently. OCR is used for many applications such as library, organization, bank cheques, number plate recognition, historical book analysis and many others applications. Various OCR tools are available for converting document images in different types of languages. The primary objective of this work is to compare the performance analysis of the three different OCR tools for extracting the text information from Tamil and Hindi document images.