The Thinning Problem in Arabic Text Recognition A Comprehensive Review

Abstract

The goal of this paper is to present an overview about the thinning problem in Arabic text recognition. Thinning "Skeletonization" is a very crucial stage in the ACR, it simplifies the text shape and reduces the amount of data that needs to be handled and it is usually used as a pre-processing stage for recognition and storage systems. The skeleton of Arabic text can be used for each of the baseline detection, character segmentation, and features extraction and also ultimately supporting the classification. Choosing or designing the effective thinning algorithm for Arabic text is crucial in ACR. In this paper, the importances of the thinning for the ACR and the usage of the text skeleton in ACR system are discussed and presented. As well as the challenges that have an impact on the thinning of Arabic text are discussed. The methods of Arabic text thinning are discussed and reviewed based on the technique used, and the methods advantages and drawbacks are discussed in details.

Printed Arabic Script Recognition: A Survey

“…Researchers summarize the state of the art of baseline detection methods in Arabic script [49]. In summary, for printed Arabic text, the standard horizontal projection method is sufficient for detecting the baseline, since the baseline in printed text is straight.…”

“…Most of the existing thinning algorithms have been designed for general purpose or other text languages [51]- [53]. However, when applying thinning algorithms to Arabic scripts, various obstacles are encountered [49]. One problem is the reduction in the number of dots in some Arabic characters as a result of the thinning process for which the number of dots is a crucial aspect in differentiating between these characters [54].…”

“…Another problem of thinning algorithms when considering Arabic script concerns preserving the connectedness of Arabic text. Some thinning approaches may not cope well with Arabic text due to its connectivity characteristic [49]. Thus, this should be taken into consideration, when selecting thinning algorithms for Arabic text.…”

Printed Arabic Text Recognition using Linear and Nonlinear Regression

“…Same result was reached even with different thinning algorithms (such as Guo-Hall thinning algorithm). Thinning Arabic script has many problems as mentioned in [18]. These problems increase difficulties of generating unique code for each character form using one font size.…”

Untitled

“…In comparison with the Latin, Japanese, and Chinese character recognition systems, development of the ACR systems did not receive adequate attention of researchers [5]. Whereas Latin character recognition started in 1940 [11], it was only in 1975 when the first attempt was made to recognize the Arabic characters [23].…”