Shape processing and analysis using the calypter

Abstract

Summary After presenting some elementary criteria that should be respected by any automatic shape analysis technique, this paper focuses on the importance of the binary image encoding method. Most image analysers simply use a raster image to represent a binary object. If, occasionally, a vectorial description is available, it is merely chosen for its performances in data compression. Data compression and shape analysis have different goals and usual methods cannot satisfy both. The calypter is a new descriptor vectorizing the shape as a set of maximal inscribed discs. It is the most efficient means of accomplishing Euclidean mathematical morphology transformations and allows for further developments in binary shape processing. A simple adaptive contour filtering technique is presented. The calypter offers local and global perception of shape characteristics. It permits complete automation of the morphometric roundness charts used in many laboratories and also generates new shape parameters. A case study of three sand populations is presented to show the pertinence of a new ‘equivalent roundness' parameter.

Segregation of the bulk blend fertilizers

“…The shape of the particles is determined by visual inspection which takes into account the shape of the two-dimensional shade of the particles. A systematic approach provides from the measurements a series of independent parameters [4]. We use in particular the measurements of elongation, roughness and of roundness.…”

Shape Analysis of Fine Aggregates Used for Concrete

“…Bluntness is based on the accurate measurement of local curvature and comparison of average local radius with the maximum radius of the inscribed disc. A descriptor, called Calypter (Pirard, 1994), is used in this study. It indicates the center and radius of the maximum inscribed disc on each point of boundary (shown in Fig.…”

Statistical models of random polyhedra∗

“…However, if the location (orientation) of X is not known, then all measurements f(X) should be invariant with respect to shifts (rotations) of X. Examples of s~ch measurements are: area (denoted by A(X)), volume, perimeter (U(X)), number of connected components, surface area or other geometric functionals and shape-ratios, see [13,22,28]. In the planar case we will often use the compacity or area-perimeter ratio of X given by 47rA(X) C(X) = U(X)2 .…”

“…shape ratios see [28] and [13]. The computational techniques for real data arc discussed in [21,22,26].…”