The Euclidean test mask T (r) is the minimum neighbourhood sufficient to detect the Euclidean Medial Axis of any discrete shape whose inner radius does not exceed r. We establish a link between T (r) and the well-known Farey sequences, which allows us to propose two new algorithms. The first one computes T (r) in time O(r) and space O(r). The second one computes for any vector − →v the smallest...

We develop an O(n2) time serial algorithm to obtain the medial axis transform (MAT) of an n×n image. An O(logn) PRAM and an O(log2n) hypercube parallel algorithm for the MAT are also developed. Both of these use O(n2) processors. Two problems associated with the MAT are also studied. These are the area and perimeter reporting problem. We develop an O(logn) time hypercube algorithm for both of t...

The paper describes an algorithm for generating an approximation of the medial axis transform (MAT) for planar objects with free form boundaries. The algorithm generates the MAT by a tracing technique that marches along the object boundary rather than the bisectors of the boundary entities. The level of approximation is controlled by the choice of the step size in the tracing procedure. Criteri...

Using the geometrical properties of medial axis of closed planar shapes, we propose a shape representation called chain of circles (CoCs), and show its use for shape matching and recognition. CoCs is directly extracted from a resulting axial con guration of shapes along boundary curves without any intermediate description like graph obtained from segmenting shapes, and has the form of vector, e...

PURPOSE OF THE STUDY When a larger opening of high-tibial osteotomy is necessary to achieve good correction of the lower extremity axis, partial release of the attachments of the medial stabilisers of the knee may be required. The aim of the study was to ascertain, in cadaver specimens, the effect of loosening the medial knee stabilisers on the magnitude of correction in medial opening-wedge hi...

PURPOSE To investigate the incidence of root tears of the posterior horn of the medial meniscus in total knee replacement arthroplasty for knee osteoarthritis and retrospectively analyze clinical results and factors associated with root tears. MATERIALS AND METHODS There were 197 knees of 140 enrolled patients who had undergone total knee replacement arthroplasty between September 2010 and Ma...

Medial axis transform (MAT) is a basic tool for shape analysis. But, in spite of its usefulness, it has some drawbacks, one of which is its instability under the boundary perturbation. To handle this problem in practical situations, various “pruning” methods have been proposed, which are usually heuristic in their nature and without sufficient error analyses. In this paper, we show that, althou...

We propose a filtering system for occlusion-aware contours. Given a point of view, we use the silhouette of a 3D shape from that point of view, its medial axis and a map of the occluded areas. Our filter is able to select the points of the medial axis which are projections of the curve-skeleton of the 3D shape, discarding all the points affected by occlusions. Our algorithm is easy to implement...

3D-shape description requires the partition of objects in different parts. In this paper, we propose a new approach based on the analysis of a 3D skeleton. The skeleton is a representation of objects by their axis of symmetry. In 3D, it is composed of surfaces associated to plate-like parts of the objet and curves associated to cylindrical parts. Our method is two parts. First, 4 types of skele...