Supercover model, digital straight line recognition and curve reconstruction on the irregular isothetic grids

Abstract

To cite this version:David Coeurjolly, Loutfi Zerarga. Supercover model, digital straight line recognition and curve reconstruction on the irregular isothetic grids.

Separable algorithms for distance transformations on irregular grids

“…In this section, we first recall the concept of irregular isothetic grids ðI-gridsÞ in 2-D, with the following definition (Coeurjolly and Zerarga, 2006):…”

Unsupervised Polygonal Reconstruction of Noisy Contours by a Discrete Irregular Approach

“…In this section, we first recall the concept of irregular isothetic grids (I-grids) in 2-D, with the following definition [3,17]. We say that two cells R 1 and R 2 are ve-adjacent if they share either a vertex or an edge, and e-adjacent if they share an edge.…”

Topological and Geometrical Reconstruction of Complex Objects on Irregular Isothetic Grids

“…Then, for each cell P i , we consider the shared segment e i between P i−1 and P i , and the current cone C j (p j , s, t) is updated. When the update procedure fails, a new cone C j+1 (p j+1 , s, t) is set up, and we add the point p j+1 to the reconstruction: to compute the new cone, authors of [4] consider the bisector of the cone and define p j+1 as the midpoint of the intersection between the bisector and the pixel P i−1 . The Figure 1 illustrates the progressive construction of cones in a k−arc, and the resulting segmentation into lines.…”

“…Moreover, this approach respects the supercover model we have just presented. The algorithm proposed in [4] to decompose a curve into segments is first based on the following definition of an irregular digital line.…”

“…We also recall the invertible reconstruction of k−arcs described in [4]. In the third part, we give details about the two main phases of our system: the description of the topology of a complex object based on the Reeb graph [20], and its polygonal reconstruction.…”