We present a new active contour model in spatiovelocity space which is based on the probability data association lter (PDAF) approach. It employs a directional-based measurement model of image potential and of opticalow along the contour points. The proposed directional approach of measurements is the basis for the velocity-based discrimination between measurements of the object to that of imag...

Unsupervised segmentation is a key challenge for automated quantification of medical images. Although a balloon model is able to detect arbitrarily shaped objects in images, it requires careful adjustment of parameters prior to segmentation. Based on global texture analyses, our method allows to set these parameters automatically for heterogeneous images such as MRI, ultrasound, or microscopy. ...

Statistical shape models are often learned from examples based on landmark correspondences between annotated examples. A method is proposed for learning such models from contours with inconsistent bifurcations and loops. It is evaluated on the task of segmenting tibial contours in knee radiographs. Results are presented using various features, distance weighted K−nearest neighbours and differin...

An active-contour-interpolation approach is proposed for semi-automatic video object generation. In this approach, user can de ne the contour of the same video object on multiple frames and the computer interpolates the missing contours automatically. Typical active contour model is adapted and the contour interpolation problem is decomposed into two directional contour tracking problems and a ...

Implicit active contour models are widely used in image processing and computer vision tasks. Most implementations, however, are based on explicit updating schemes and are therefore of limited computational efficiency. In this paper, we present fast algorithms based on the semi-implicit additive operator splitting (AOS) scheme for both the geometric and the geodesic active contour model. Our ex...

A welded structure must be inspected to guarantee that the weld quality meets the design requirements to assure safety and reliability. However, X-ray image analyses and defect recognition with the computer vision techniques are very complex. Most difficulties lie in finding the small, irregular defects in poor contrast images which requires pre processing to image, extract, and classify featur...

This paper presents a novel binary speed term for tracking objects with the help of active contours. The speed, which can be 0 or 1, is determined by local nonlinear filters, and not by the strength of the gradient as is common for active contours. The speed has been designed to match the nature of a recent fast level-set evolution algorithm. The resulting active contour method is used to track...

Snakes as originally proposed by Kass, Witkin and Terzopoulous are active contour models which minimise an expression of energy to locate image features. The original formulation involves hundreds of state variables and does not submit to a real-time implementation. We explore the use of a B-spline model of the feature to reduce the state space of the problem. Using a coarse to fine feature sea...

Monitoring the shape changes of the optic disk is crucial for the early detection of glaucoma. This requires the optic disk to be segmented from the surrounding fundus. Previous methods required the boundary to be identified manually, for example, by specifying four control points on the boundary. This is not practical for routine clinical analysis, intra-observer and inter-observer variations ...

In recent years the eld of active contour based image segmentation have seen the emergence of two competing approaches The rst and oldest approach rep resents active contours in an explicit or parametric manner corresponding to the Lagrangian formulation The second approach represent active contours in an implicit manner corresponding to the Eulerian framework After comparing these two approach...