A new circle estimator is proposed for solving heavy subpixel error on circle center in the case of noticeable distortion. It is based on an innovative point of view over active contours process blending mathematical morphology and electronic phenomenon that furnishes a multi-level image in a single pass from the approximated form of objects to a full detailed one. A comparison with least-mean ...

This paper proposes a two-step circle detection algorithm using pairs of chords. It is shown how a pair of two intersecting chords locates the center of the circle. Based on this idea, in the ®rst step, a 2D Hough transform (HT) method is employed to ®nd the centers of the circles in the image. In the second step, a 1D radius histogram is used to compute the radii. The experimental results demo...

In this paper an automatic segmentation method for accurate pupil boundary detection for iris recognition purpose using graph cuts is presented. Most iris segmentation algorithms used for iris recognition consider the pupil as a circular area and fit a circle to its boundary. Considering the pupil to be a circle is a method which is sensitive to the imaging condition because in the case of off ...

one method of treating ruptured anterior communicating aneurysms is presented. this permits early clipping through a bifrontal flap. key branches of the circle of willis are temporarily occluded by special removable clips before exposing and permanently clipping the aneurysm. this requires the use of hypothermia at 28'0. and other technical aids described. the risk of a fatal recurrent hemorrha...

In this paper we present a method for the numerical approximation of the smallest eigenvalue of a nonlinear eigenvalue problem using the finite element method. Numerical results are presented for some special domains when the domain is bounded by a square, a ”circle”, a ”semicircle”, or a quadrant of a ”circle”. We compare the exact solutions with the approximate solutions when the exact soluti...

Recently, a new numerical method has been proposed to compute rotation numbers of analytic circle diffeomorphisms, as well as derivatives with respect to parameters, that takes advantage of the existence of an analytic conjugation to a rigid rotation. This method can be directly applied to the study of invariant curves of planar twist maps by simply projecting the iterates of the curve onto a c...

A new method of amplifying short DNA molecules immobilized on a solid support has been developed. This method uses a solid-phase rolling circle replication reaction, termed rolling circle amplification (RCA). The probe consists of a single-stranded DNA primer anchored at the 5' terminus to a solid support and a single stranded DNA template hybridized to the immobilized primer. Here, DNA ligase ...

We present a new method for detecting circles on digital images. This transform is called the circlet transform and can be seen as an extension of classical 1D wavelets in 2D: each basic element is a circle convolved by a 1D wavelet. In comparison with other circle-detector methods, mainly the Hough transform, the circlet transform takes into account the finite frequency aspect of the data: a c...