The Nyström method is a popular technique for computing fixed-rank approximations of large kernel matrices using a small number of landmark points. In practice, to ensure high quality approximations, the number of landmark points is chosen to be greater than the target rank. However, the standard Nyström method uses a sub-optimal procedure for rank reduction mainly due to its simplicity. In thi...

We describe a model-based method of generating realistic mass lesions and placing them in appropriate locations on normal mammogram backgrounds. These lesions are highly irregular in shape and have no consistent internal landmarks. Thin plate splines are used both in modelling the background to each lesion, and to warp examples when training an appearance model.

We describe a new approach to modelling the appearance of structures in grey-level images. We assume that both the shape and grey-levels of the structures can vary from one image to another, and that a number of example images are available for training. A 2-D image can be thought of as a surface in 3 dimensions, with the third dimension being the grey-level intensity at each image point. We ca...

Computer Vision has recently witnessed great research advance towards automatic facial points detection. Numerous methodologies have been proposed during the last few years that achieve accurate and efficient performance. However, fair comparison between thesemethodologies is infeasiblemainly due to two issues. (a) Most existing databases, captured under both constrained and unconstrained (in-t...

In this work, robot navigation is approached using visual landmarks. Landmarks are not preselected or otherwise defined a priori; they are extracted automatically during a learning phase. To facilitate this, a saliency map is constructed on the basis of which potential landmarks are highlighted. This is used in conjunction with a modeldriven segregation of the workspace to further delineate sea...

Earlier work has shown that the acoustic landmarks in speech [1,2], proposed to be important in lexical access, are largely preserved in spontaneous American English Speech [3]. Moreover, the loss of acoustic landmarks predicted from word’s lexical representation is systematic and predictable. This study reports preliminary analysis of factors that govern whether a landmark will be realized as ...

In this paper, we discuss a computationally efficient approximation to the classical multidimensional scaling (MDS) algorithm, called Landmark MDS (LMDS), for use when the number of data points is very large. The first step of the algorithm is to run classical MDS to embed a chosen subset of the data, referred to as the ‘landmark points’, in a low-dimensional space. Each remaining data point ca...

We present an approach to the landmark-based robot localization problem for environments, such as RoboCup middle-size s occer, that provide limited or low-quality information for l ocalization. This approach allows use of different types of measurements on potential landmarks in order to increase landmark availability. Some sensors or landmarks might provide only range (such as field walls) or ...

We introduce a novel multi-step approach to improved detection of 3D anatomical point landmarks in tomographic images. Such landmarks serve as important image features for a variety of 3D medical image analysis tasks (e.g. image registration). Existing approaches to landmark detection, however, often suffer from a rather large number of false detections. Our multi-step approach combines an exis...