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This paper proposes a novel modeling method for a hybrid quad/triangle mesh that allows to set a family of possible shapes by controlling a single parameter, the global curvature. The method uses an original extension of the Laplace Beltrami operator that efficiently estimates a curvature parameter which is used to define an inflated shape after a particular operation performed in certain mesh points...
We propose an image stitching method which can compose the images with similar overlapped regions seamlessly. Traditional minimal error boundary (MEB) based method can't produce correct stitching result when the input images exist photometric inconsistency. To cope with the problem, we adopt the weighted sum of gradient and curvature as the robust feature, which represent the primary content of the...
A 3D-mesh watermarking method is proposed in this paper. The watermarking occurs in the spherical coordinates system, where only the vertex norm of each point is modified. The embedding method is based on Spread Transform Dither Modulation (STDM). A perceptual model based on the curvature and the roughness of the 3D mesh is defined and is used to modulate the STDM method. Our results show that the...
Computer vision involves image edge detection which is crucial in outline capturing systems for decomposing and describing an object. This paper presents a scalable parallel algorithm skeleton for outline capturing and object recognition based on first order difference chain encoding. UNIX based Intel Xeon 2-Quadra-Core system is used for the implementation of the parallel algorithm. The algorithm...
An anisotropic smoothing algorithm for removing noise of triangular mesh models is proposed. First, the desirable normals of the triangles are approximated using our desirable normal computing schemes, and then each vertex is repositioned according to desirable normals of adjacent triangular faces. The desirable normals estimated by a weighted sum of normals at neighboring faces. If the face differs...
Segmented cross sectional MRI images were used to construct 3D virtual models of the carotid bifurcation in 5 healthy volunteers. Geometric features such as bifurcation angle, planarity angle, asymmetry angle tortuosity and curvature were calculated for the normal head posture and were compared to the equivalent values acquired with the head rotated clockwise by up to 80 degrees. The results obtained...
In this paper, we extend Razdan and Bae's second-order local fitting method to construct an effective third-order fitting patch. Compared to other estimation algorithms, this weighted bicubic Bezier patch more accurately obtains the normal vector and curvature estimation of a triangular mesh model. Furthermore, we define the principal geodesic torsion of each vertex on the mesh model and estimate...
Existing polyp detection methods rely heavily on curvature-based characteristics to differentiate between lesions. However, as curvature is a local feature and a second order differential quantity, noise caused by small bumpy structures and incoherent curvature fields of a discretized volume or surface can greatly increase the number of false positives (FPs) detected. This paper investigates a spectral...
B-spline active surfaces have been extensively utilized to perform automated feature extraction in medical imaging. In this study we focus our attention on the accuracy of 3D B-spline active surface modeling of very small objects. In particular we investigate different smoothing conditions, based upon the regularization of L1 and L2 norms of surface curvature. The model accuracy is directly determined...
Accurate and reliable detection of minutiae from the fingerprint images is an important factor in the performance of automatic fingerprint identification systems (AFIS). Fingerprint image quality evaluation and appropriate enhancement technique are critical steps for accuracy of minutiae detection algorithm. Most fingerprint enhancement algorithms rely heavily on local orientation of ridge flows....
A closed curve in the plane can be described in several ways. We show that a simple representation in terms of radius of curvature versus normal direction has certain advantages. In particular, convolutional filtering of the extended circular image leads to a closed curve. Similar filtering operations applied to some other representations of the curve do not guarantee that the result corresponds to...
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