Research Contents/FSCI のバックアップ(No.31)

FSCI †

FSCI is the abbrevation of the Fuzzy Spline Curve Identifier developed by us.

Nowadays, with the spread of tablets and PDA devices which use pen input, direct sketch drawing on displays is rapidly becoming possible. Although recognition of handwriting has already been implemented, recognition of sketch drawing is still being researched. Therefore, we have given birth to a completely new method of recognizing sketch drawing of curves, called FSCI.

When we consider general drawing applications, basic shapes such as circle, ellipse, triangle, rectangle are needed. Therefore, past sketch recognition methods that can recognize "triangle", "rectangle" and such shapes were popular to fit the use of drawing applications. But in FSCI, to achieve general purposeness, we have intentionaly excluded these shapes and limited the recognized objects to the 7 primitive curves (line, circle, circular arc, ellipse, elliptical arc, closed free curve, open free curve).

The reason behind this is that most of the complex CAD drawings are can be presented as a combination of these 7 primitive curves. For an example, after recognizing the line from sketch drawing, it becomes very easy for the applications to identify shapes such as triangle or rectangle.

Fig. 1 Basic curve shapes identified by FSCI

Identifying these 7 curve shapes seeem to be simple at the first glance. But these contain inclusive relationships such as "circle is a special case of ellipse", "ellipse is a special case of closed free curve", "circle is a special case of circular arc", "ellipse is a special case of elliptical arc". Therefore, in the traditional methods which only make use of shape information, it is difficult to identify shapes that have inclusive relationships. In FSCI, we use the unique technique that uses the vagueness (also called fuzziness) of the drawing manner to understand the user's intentions in order to solve this problem.

Fig. 2 The inclusive relationships of the curve shapes

Inside FSCI, the sketch drawing is represented as a fuzzy spline - which is a spline curve which contains fuzziness - by estimating the shape as well as the roughness of the drawing action.

Moreover, the identification is done by fuzzy reasoning that selects the most simple curve from among the possible curve shapes. As such, in FSCI, a sketch is identified as a simple curve when drawn roughly and on the other hand as a complex curve when drawn carefully. As a result, users can use these characteristics and convey their intentions to FSCI appropriately by controlling their drawing manner as well as the shape of drawing.

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Identifying characteristics of FSCI †

Fuzzy spline curve is an extention of spline curve based on fuzzy sets so that it can represent the curve shape as well as the positional vagueness of sketch drawing. In FSCI, the fuzziness (vagueness) of each point of the sketched curve is calculated with propotion to the speed and the acceleration of the drawing manner and then the fuzzy spline is generated.

Fig. 3 shows few examples of input sketch curves.

Fig. 3 Sketch curve

Fig. 4 shows fuzzy spline curves. The green circles shows the fuzziness at each point. Fuzziness becomes large in places drawn quickly, roughly and small in places drawn slowly, carefully.

Fig. 4 Fuzzy spline curves

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