Logo recognition : theory and practice Used by companies organizations and even individuals to promote recognition of their brand logos can also act as a valuable means of identifying the source of a document. E business applications can retrieve and catalog products according to their logos. Governmental agencies can easily inspect goods using smart mobile devices that use logo recognition techniques. However because logos are two dimensional shapes of varying complexity the recognition process can be challenging. Although promising results have been found for clean logos they have not been as robust for noisy logos. Logo Recognition: Theory and Practice is the first book to focus on logo recognition especially under noisy conditions. Beginning with an introduction to fundamental concepts and methods in pattern and shape recognition it surveys advances in logo recognition. The authors also propose a new logo recognition system that can be used under adverse conditions such as broken lines added noise and occlusion. The proposed system introduces a novel polygonal approximation a robust indexing scheme and a new Line Segment Hausdorff Distance (LHD) matching method that can handle more distortion and transformation types than previous techniques. In the first stage raw logos are transformed into normalized line segment maps. In the second stage effective line pattern features are used to index the database in order to generate a moderate number of likely models. In the third stage an improved LHD measure screens and generates the best matches. A comprehensive overview of logo recognition the book also presents successful applications of the technology and suggests directions for future research. Preface Logo recognition is of great interest in the document and shape matching domain. Logos can act as a valuable means of identifying sources of documents. By recognizing the logo semantic information about the document is obtained which may be useful to decide whether or not to analyze the textual parts. Some promising results have been found for clean logos; however they can hardly be robust for noisy logos. This book summarizes our recent research on logo recognition. We rst in this book (Chapter 2) provide some introduction and fundamental knowledge for pattern recognition. Readers can safely skip reading it if you feel you are familiar with these topics. In order to develop a logo recognition method that is robust to be employed under adverse conditions such as di erent broken curves added noise and occlusion a logo recognition system based on line pattern features is proposed in this book. To achieve the desired accuracy and effciency the proposed system employs a three stage hierarchy polygonal approximation indexing and matching. In the first stage the raw logos are transformed into normalized line segment maps (LSM); in the second stage e ective line pattern features are used to index the database to generate a moderate number of likely models with respect to a test image; in the third stage an improved Line Segment Hausdor Distance (LHD) measure is proposed to screen further and generate the best matches