
NuHAG :: TALKS
Talks given at NuHAG events






Fast spacescale filtering of the wavelettransform of medical ultrasound images Preben Graaberg Ness Department of Mathematical Sciences,
Norwegian University of Science and Technology NORWAY given at strobl07 (..) id: 826 length: min status: accepted type: poster LINKPresentation: ABSTRACT:
The purpose of our investigation is to construct an efficient multiscale edgedetector for medical ultrasound images using the continuous wavelettransform. Typically such detectors require that the wavelettransform is computed at several scales, merely in order to decide which information should be combined across scales. Our focus has been if/how one can determine which modulusmaxima are connected by a maximaline if computing the wavelettransform at only a few scales. We propose an algorithm which (when applied to medical ultrasound images) uses as few scales as possible.
The theoretical part of the investigation has focused on how the mutual amplitude and position of stepedges in a signal will influence the position and amplitude of the modulusmaxima across scales. This has been used to find bounds for which scales one has to compute the wavelettransform, in order to ensure that one is able to determine which modulusmaxima are connected by a maximaline.
Numerical investigation of the algorithm applied to rays in medical ultrasound images of braintumors, indicates that for such type of signals our algorithm is close to optimal if using scales s=2^j, and still good when using scales s=2^2j.
