LWDOS: Language for Writing Descriptors of Outline Shapes

Abstract

A new method to obtain a rough description of a 3-D object from its outline shape is presented in this paper. Firstly the outline shape is split up into parts that are related in a connectivity graph. The boundary features of every part (lines, curves) and the information about its junction with other parts are extracted in order to provide a semantic content to the outline shape graph. A specific language to describe this graph has been developed. Finally, some results obtained applying our approach over real images are presented and discussed

Matching Descriptors of Noisy Outline Shapes

“…39 (OXY) is the referential attached to MR. The origin O is the top left edge of MR and the OX (resp.…”

“…The second step is the parts description and uniqueness building. [39][40][41] The first step of a shape description is its decomposition into parts and separating lines. For this, we sweep up the outline shape from top to bottom following the horizontal direction of the (MR), and we locate concave points for which the contour changes the direction; top-bottom-top or bottom-top-bottom (see Fig.…”

“…39 (2) Compare the obtained descriptors. If they are similar, we deduce that the two silhouettes have the same structure (same coarse descriptors).…”

“…These are part-based and appearance-based methods because we respectively use parts of 2D silhouettes and silhouettes textual descriptors for the matching process. 39 Due to noise, silhouettes textual descriptors may be very different, although these silhouettes look alike.Comparing such silhouettes descriptors will result in a mismatch.…”

Discriminative outlines parts for shape retrieval

“…In a previous work [11], we have proposed a representation of outline shapes that decomposes a shape into hierarchical parts obtained by a sweeping of the shape following the direction of the length of the rectangle of minimum area encompassing it. The resulting representation is a global descriptor which gives topological information about the shape and local descriptor that describes geometric attributes of the part boundaries.…”