Work on the problem of handwritten text recognition in Urdu script has been an active research area. A significant progress is made in this interesting and challenging field in the last few years. In this study, the authors presented a comprehensive survey for a number of offline and online handwritten text recognition systems for Urdu script written in Nastaliq font style from 2004 to 2019. Following features make their contribution worthwhile and unique among the reviews of a similar kind: (i) their review classifies the existing studies based on types of recognition systems used for Urdu handwritten text, (ii) it covers a very different outlook of the recognition process of the Urdu handwritten text at different granularity levels (e.g. character, word, ligature, or sentence level), (iii) this review article also presents each of surveyed articles in following dimensions: the task performed, its granularity level, dataset used, results obtained, and future dimensions, and (iv) lastly it gives the summary of the surveyed articles according to the granularity levels, publishing years, related tasks or subtasks, and types of classifiers used. In the end, major challenges and tasks related to Urdu handwritten text recognition approaches are also discussed in detail.

中文翻译：

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乌尔都语手写文本识别：一项调查

关于乌尔都语手写文字识别问题的研究一直是活跃的研究领域。过去几年，在这个有趣且充满挑战的领域取得了重大进展。在这项研究中，作者对2004年至2019年期间使用Nastaliq字体编写的大量针对Urdu脚本的离线和在线手写文本识别系统进行了全面调查。以下类似功能使它们的贡献值得且独特： （i）他们的审查根据用于乌尔都语手写文本的识别系统的类型对现有研究进行分类，（ii）它涵盖了乌尔都语手写文本在不同粒度级别（例如字符，单词，连字的识别过程）的截然不同的观点，或句子级别），（iii）这篇评论文章还按以下维度介绍了每篇被调查的文章：执行的任务，其粒度级别，使用的数据集，获得的结果以及将来的维度，以及（iv）最后，它根据以下内容提供了被调查文章的摘要：粒度级别，发布年份，相关任务或子任务以及使用的分类器类型。最后，还详细讨论了与乌尔都语手写文本识别方法有关的主要挑战和任务。