Introduction to Sketch Recognition by Tracy Hammond and Kenneth Mock

Comment:
1. Ben's Blog
Summary:

This paper is an overview of almost all the pen based technology available today. Sketchpad the first pen based system was created by Ivan sunderland in 1963. This system which utilized a pen and set of keys as mode of input to create simple graphics. From this primitive form , the pen based evolved over 40 years to tablet PCs, convertibles, whiteboards, USB connected Pen tablets, ... which are cheaper and affordable.These pen based systems use Digitizers to capture Pen based activities. These digitizers are of 2 type - Active and Passive. Passive digitizers detect touch, so even finger would be recognised as pen. The drawback of these digitizers are that they recognise the touch from palm and other things which are in contact with it. This causes vectoring. These digitizers usually have low accuracy and resolution. Active digitizers on the otherhand, recognise electromagnetic waves to detect pen activities(only special pens) and it is more precise.

This paper also discusses about the various applications of Pen based systems. Pen based systems have found themselves useful in teaching. Application like One Note, Annotations on Powerpoint, ... can be used to make presentation more dynamic and user defined. With the pen based systems, the field of sketch recognition has also grown into an important field. This field has application in diverse areas. ChemPad , an application which can recognise sketched diagran into a 3D view of the molecular structure. Hand Sketch, an application which recognises hand drawn symbols and plays music accordingly. This paper also discusses about a Framework(FLUID), which can used to create sketch interfaces. This framework uses ,LADDER and GUILD. LADDER, a language for defining objects that has to be identified by the application.
GUILD, a recognition system which recognises shapes based on the LADDER definition. The output of this system can be fed to Back end system , which would do domain specific jobs.

Discussion:
- Pen based systems have grown upon application where mouse cannot be used. Writing, sketching and gestures where using mouse would be difficult.So there raises the question - Can pen replace mouse? I think this would be difficult because we are used to mouse for so long that any change would cause discomfort to the users. This would require change in UI to either accomodate mouse activities( the way it is done now) or create a new UI which would not need mouse.