We address the task of covering a closed orientable surface embedded in < without any prior information about the surface. For applications such as paint deposition, the e ector (the paint atomizer) does not explicitly cover the target surface, but instead covers an o set surface | a surface that is a xed distance away from the target surface. Just as Canny and others use critical points to loo...

The traditional Canny edge detector has some drawbacks. Gaussian filter can’t remove the impulsive noise. Moreover, it is difficult to automatically select the dual-threshold. Especially when the noise intensity increases, the dual-threshold selection method of traditional Canny detector is invalid. In this paper, we present an adaptive Canny edge detector using histogram concavity analysis. Th...

Intraoperative optical imaging of exposed organs in visible, nearinfrared, and infrared (IR) wavelengths in the body has the potential to be useful for real-time assessment of organ viability and image guidance during surgical intervention. However, the motion of the internal organs presents significant challenges for fast analysis of recorded 2D video sequences. The movement observed during su...

The Canny edge detector is widely used in computer vision to locate sharp intensity changes and to nd object boundaries in an image The Canny edge detector classi es a pixel as an edge if the gradient magnitude of the pixel is larger than those of pixels at both its sides in the direction of maximum intensity change In this paper we will show that de ning edges in this manner causes some obviou...

The edgelets produced by the Canny edge detector are first thresholded to reduce weak clutter. Beginning from an edgelet, we track along connected neighbours to get a list of edgelets. If one edgelet has more than two neighbours, we check all possible extensions of the curve, and segment the curves on a largest-first basis, breaking the others to form separate curves. This removes small spurs e...

Skeletonization is a morphological operation that transforms an original object into a subset, which is called a ‘skeleton’. Skeletonization has been intensively studied for decades and is a challenging issue especially for special target objects. This paper proposes a novel approach to the skeletonization of text images based on stroke width detection. First, the preliminary skeleton is detect...

In this paper we present a corner detection which makes use of eigenvalues of covariance matrices of different support regions over edge points. Edges are first extracted through the use of Canny edge detection, and then determine corners according to eigenvalues product of covariance matrices of the edge at various regions of support. Experimental results show that the proposed method has more...

In this paper we prove simple estimates relating the value of a complex homogeneous polynomial at a point to the distance of the point to the zero set of the polynomial, and also the distance to the zero set along a projective line to the distance in projective space. Our motivation for doing this was to give a quantitative aspect to the algorithm of W. Zulehner and to relate it to the algorith...