Introduction to Sketch Recognition

Tracy Hammond and Kenneth Mock

Comments on others

daniel's blog

Summary

The authors present an overview of pen-based interactive systems and applications for these systems. The paper begins with a summary of the technology used in pen-based interaction. Passive digitizers allow the use of any stylus including one's finger, but suffer from vectoring (unintended triggers when for example a palm brushes the digitizer), require touch before recognition, and have lower resolution and accuracy than active digitizers. An active digitizer needs a special stylus, but this eliminates the problems of vectoring and required touch associated with passive digitizers.

An outline of software features across operating systems is described in the paper. Microsoft Windows has the largest feature set.

The authors compare and contrast the use of large screen displays such as SMART Board versus smaller TabletPC displays. Large displays offer more screen real estate and allow displaying information to multiple people without the need for individual displays. The TabletPC allows for greater accuracy and flexibility in movement.

Several applications of sketch recognition are presented. A few of these are:

• ChemPad: converts sketched chemical diagrams to 3-D models


• LADDER MechEng: recognizes and simulate hand-drawn mechanical engineering diagrams


• LADDER FSM: draw finite state machines, and run an input through them
  

The process of using LADDER and the GUILD system to build a new sketch interface is outlined. The domain specific information is defined using LADDER, and GUILD automatically generates a system for recognizing sketches in that domain.

The paper concludes with two case studies and a future work section. The case studies illuminate the advantages of a TabletPC-based lecture, pointing to higher student involvement and better attention spans.

Discussion

The contribution of this paper (or fragments of a book) is an overview of sketch recognition technologies and their applications. Also, the paper points out the benefits of using sketch recognition technologies in an educational environment.

As this paper is an overview, it's difficult without significant knowledge in the field to point at possible faults. Difficulty in reading it arose from its fragmentation, but only until I realized it was not a continuous document.

Future work to pursue would include mentioning more related hardware (possibly a brief discussion of multi-touch and comparison). As well, evaluating designed systems to further emphasize the value of sketch recognition systems.