by
Tracy Hammond and Randall DavisSummary
There are people who are good at making sketch recognition systems, unfortunately those people aren't usually domain experts. The opposite is true, some people really know their domains, but it is difficult for them to transfer this knowledge into a sketch recognition system . LADDER allows for the description of a domain's shapes at a simple level. This description consists of describing the primitive shapes, and the constraints on those primitive shapes. This description should also include information about how the shape should be edited and how it should be displayed to the user.In LADDER shapes are built hierarchically re-using low-level shapes. Both hard and soft constraints can be put on shapes; thus the way a user draws the shape must not be identical to be recognized, but if a shape is often drawn in a common progression, this information could be used in recognition.
A user study was done with thirty users to gain an understanding of how people go about describing shapes and constraints in common language. These concepts were built itno the description language for LADDER.
LADDER is unable to describe abstract shapes, shapes must be composed of primitive shapes, and curves are inherently difficult for the system. The paper goes on to discuss the shape definitions, how shapes can be grouped, and the predefined shapes, conditions and display methods. Also, vectors is discussed. Vectors are used to recognize shapes with a variable number of sub-shapes. The example given is a dashed-line. Shapes are recognized using a bottom-up approach.
1 comment:
First.
And yes, complex shapes are frustrating.
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