Contour line extraction from a topographical map is an integral part of Geographical Information System. Traditional technique for contour line extraction include manual digitization, this is a time consuming, tedious and a costly process. In addition the effectiveness of the result highly relies on the ability and skill of the researcher responsible for the same. To aid research initiatives th...

The famous London Underground map shows the Thames and named metro stations with railway tracks as straight line segments. Strictly speaking, it is not a map that aims at a metrically accurate depiction of the network, but it is rather a diagram that accentuates the topological relations of Underground stations. Henry “Harry” C. Beck produced the first sketch for the famous diagram in 1931. His...

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This paper presents the application of two different active contour models for the segmentation of highresolution TerraSAR-X data. Both methods facilitate the detection of land-water-boundaries in semi-automated procedures and can be used to delineate flood extent and to map open water surfaces in general. For the extraction of smooth water bodies amplitude thresholding approaches are quite com...

This paper proposes a probabilistic prior-based active contour model for segmenting human brain MR images. Our model is formulated with the maximum a posterior (MAP) principle and implemented under the level set framework. Probabilistic atlas for the structure of interest, e.g., cortical gray matter or caudate nucleus, can be seamlessly integrate into the level set evolution procedure to provid...

In this study, contours of a brain tumor on a single slice tomography image were derived by using image correlation technique. Four different methods were used to compare the validity of the derived contours. Contour map of the brain tumor was generated by using 2D image correlation technique with raw pixel , perceived brightness (luminance), optical density and Relative radiation dose data. Th...

Speckle and low contrast make ultrasound image segmentation a difficult task. This paper presents an original robust active contour energy and the corresponding quasi-automatic initialization. Both are based on the coefficient of variation gradient vector fl ow. Our approach combines anisotropic diffusion with the gradient vector fl ow field. The gradient vector fl ow is calculated from a map o...

A variety of operations have been described in recent years that are intended as digital solutions to a basic class of cartographic adjacency problems. A selection of these algorithms includes: interpolation; Voronoi diagrams of point distributions (proximal maps, Thiessen polygons); skeleton encoding (of scanned characters or polygons); corridor selection, or extraction of regions within speci...

This paper presents a new algorithm of disparity map segmentation in planar facets. Originalities of this method lies in the process of dense disparity map estimation, using the dynamic programming subject to interest points previously extracted. The segmentation of this map uses the normal vector at each pixel surface. The matching of pixels between the two images by dynamic programming provid...

We investigated whether observers use rate of change of curvature in visually extrapolating contour shape. Arcs of Euler spirals with positive or negative rate of change of curvature gamma (hence linearly increasing or decreasing curvature) disappeared behind the straight-edge of a half-disk occluder. Observers adjusted the position and the orientation of a line probe around the curved portion ...