Digital Ink to Form Alignment for Electronic Clipboard Devices

This paper addresses the problem of aligning handwritten input captured as digital ink to form templates, which occurs when paper forms are filled using "electronic clipboard" devices such as the ACECAD DigiMemo. Due to certain non-linearities in the digitizer hardware, the ink that is obtained from these devices is seldom in exact alignment with the "soft" form template. While not a concern for simple note capturing applications, this poses a serious problem for form processing applications. In this paper, we explore image registration approaches to solve the ink alignment problem. Two kinds of point pattern approaches to solve this alignment problem are explored. One method considers ink as "rigid" and a global transformation matrix is used to align the ink with the form template, while the second assumes only minor distortions and hence adopts a more local approach. We compare the performance of the two approaches and present some preliminary results. A summary of the work in progress and next steps are presented in conclusion.