The fuzzy-spatial Descriptor for the online graphic recognition: Overlapping matrix algorithm

In this paper we present the algorithm of our fuzzy-spatial descriptor for symbol recognition in on-line sketches. Fuzzy sets are used to enhance this approach to cope with the inherent distortion of freehand drawings. It allows handling some primitive irregularities due to different ways of drawing in complex composite forms. The descriptor provides complete local information of the primitives that consist of only straight lines. This descriptor used the opening angle between primitives and its overlapping properties in 1D projection to describe its local spatial properties. Segmentation by curve and pen-speed properties of each drawing has been used in obtaining our basic primitives. The experiment results show that a part from its rotational-invariant, this descriptor is also robust to multi-scale of segmentation of its primitives.