An accurate detection of the radiation field is crucial to 3D conformal radiotherapy (3D-CRT). Automated techniques to detect the field edges on double exposure portal images have previously focused on thresholding techniques. In this paper, we present a new approach based on a curve propagation technique (the Fast Marching method) which proves to be more effective at detecting the radiation fi...

In this paper, we propose to use image pixels for geometry reconstruction with a shape from silhouette approach. We aim at estimating shape and normal for the surface of a single object seen through calibrated images. From the voxel-based shape obtained with the algorithm proposed by R. Szeliski in [18], our main contribution concerns the use of image pixels together with marching cubes for con...

The Centered Cubic Lattice method is used for an iso-surface extraction. This paper focuses on its comparison with other fundamental methods (Marching Cubes, Marching Tetrahedra) that are also used to extract an iso-surface from regular volume data. Iso-surfaces that are generated using above mentioned methods and mathematical data are compared due to area and volume approximation. The Hausdorf...

This paper presents a new method for polygonization of implicit surfaces. Our method put emphasis on the shape of triangles of the resulting polygonal mesh. The main advantages of the triangulation presented are simplicity and the stable features that can be used for next expanding. The implementation is not complicated and only the standard data structures are used. This algorithm is based on ...

This paper presents a powerful and general purpose tool designed to extract characteristic lines from 3D images 1. The algorithm, called Marching Lines, is inspired from the Marching Cubes algorithm, which is used to extract iso-value surfaces from 3D images. The Marching Lines algorithm extracts with sub-pixel accuracy the 3D lines corresponding to the intersection of two iso-surfaces from two...

The existing Fast Marching methods which are used to solve the Eikonal equation use a locally continuous model to estimate the accumulated cost, but a discontinuous (discretized) model for the traveling cost around each grid point. Because the accumulated cost and the traveling (local) cost are treated differently, the estimate of the accumulated cost at any point will vary based on the directi...

The exploration and construction of maps in unknown environments is a challenge for robotics. The proposed method is facing this problem by combining effective techniques for planning, SLAM, and a new exploration approach based on the Voronoi Fast Marching method. The final goal of the exploration task is to build a map of the environment that previously the robot did not know. The exploration ...

Dental radiographs have been widely used by dentists in monitoring the progress of the periodontal defect treatment. And more importantly, digital dental X-rays make computer aided dental X-rays analysis possible and convenience. In digital dental X-rays the regions of the cysts are of low contrast and the pixel intensity distribution is not homogenous so cyst segmentation is a complex problem ...