6. English Language Handwriting Recognition Interfaces

Handwriting had been an excellent means to communication and documentation for thousands of years, and this chapter deals with handwriting recognition as a method of entering text into a computer. Handwriting is a learned skill, but because it has a long history and is learned in early school years, many consider it more natural than the alternative learned skill of text entry by either standard or virtual keyboards. Nevertheless, keyboarding is usually considerably faster than handwriting recognition of standard alphabets (Zhai & Kristensson, 2003). With the increase of text entry on mobile computing devices, however, shorthand alphabets and other shorthand notations, such as chatroom abbreviations, have been explored with the aim of increasing the speed and recognition rate of handwritten text input. In this chapter we deal with the recognition of English handwriting and begin by discussing the English handwriting styles used for computer input, the fundamental property of handwriting, and what makes handwriting recognition difficult. For simplicity, we focus our discussions on the alphabetic characters and omit detailed coverage of punctuation, numbers, and other symbols required for complete working systems. We also omit dealing with correcting and editing the input where the current trend is to use gestures and editing symbols (see Chapter 7). We briefly discuss offline handwriting recognition which falls in the area of optical character recognition (OCR) where only the static information is available. Here we cover line, word, and character segmentation, and character recognition technologies. Because this book deals primarily with real-time text entry, we discuss more thoroughly the area of online handwriting recognition where pen movements are tracked. Here we describe the dynamic information and the digitizer equipment that captures it, and then cover the usual recognition strategies and especially those that deal with the problems of segmentation and dynamic writing variation. We then describe shorthand techniques for speed writing, including shorthand alphabets and other shorthand for words and phrases. We briefly discuss some of the commercial handwriting systems for laptop and handheld computers. Finally, we present a case study and suggestions for further reading.