DSB Seminars 2017

Seminars are usually on Thursdays from 12.15 to 13.00 (maximum) in the DSB-lab (room 4270, 4. floor North) unless otherwise noted.

Organizers: Ole Marius Hoel Rindal (omrindal@ifi.uio.no) and Sverre Holm (sverre@ifi.uio.no).

Previous

Time and place: Oct. 31, 2017 2:15 PM3:00 PM, DSB-labben, rom 4270, OJD-hus

Anne Catrine T Martinsen fra gruppe for CT fysikk og teknologi ved Oslo universitetssykehus (OUS) presenterer planer for et nytt bildesenter.

 

Time: Sep. 27, 2017 12:15 PM1:00 PM

Title: Phase Detections with Low Complexity Adaptive Beamforming on Swath Sonars

Presenter: Tor Inge Birkenes Lønmo

Affiliation: DSB-group (Digital signal processing and image analysis) and Kongsberg Maritime.

Abstract:

Time and place: Aug. 31, 2017 12:15 PM1:15 PM, DSB-lab

Antoine Blachet, Stine Hverven, Sri Nivas Chandrasekaran will be going to conferences next week, International conference and exhibition on Underwater Acoustics for Antoine and IEEE International Ultrasonics Symposium for Stine and Sri Nivas. 

Time: June 1, 2017 12:40 PM1:05 PM

EAGE Presentation

Time: June 1, 2017 12:15 PM12:25 PM

Presentation for EAGE conference, Paris 2017

Time and place: May 9, 2017 10:15 AM11:00 AM, 4270 (DSB lab)

Prof. Marco Loog, head of the Pattern Recognition Laboratory at Delft University of Technology

As this talk is primarily meant as a means to identify shared interests and possibilities to interact with people from the group [or from UiO in general?], I will keep it fairly broad. Firstly, I will describe what generally is my take on research, which I mainly do within the fields of pattern recognition and machine learning, but also a bit within the areas of multi-scale and medical image analysis. Secondly, I will give a brief overview of some of my main research interests. These are topics that I definitely would be interested in collaborating on. Finally, if time permits [and I'm sure it does], I will discuss one or two specific results obtained that I consider both illustrative for my work and important results as such.

Time and place: Apr. 27, 2017 12:15 PM1:00 PM, DSB-lab

Seminar by Md. Zia Uddin, Post Doc in the Robotics Group

Time: Mar. 30, 2017 12:15 PM1:00 PM

Title: Visualization techniques in multichannel images

Presenter: Roy Hansen

Affiliation: FFI (Forsvarets Forskningsinstitutt) DSB-group.

Abstract: The visualization of the results is important in the science of pulse-echo imaging. When the data contains two or more channels of independent information (data values per independent spatial pixel), there are choices of how the results can be combined into informative images for display. Examples of multichannel data are echo strength (reflectivity) and Doppler in medical ultrasound;  echo strength and depth (range) in mapping sonar; individual scattering parameters in polarimetric radar; and diversity in observation orientation and frequency in wideband widebeam pulse-echo imaging. In this talk, we consider interferometric synthetic aperture sonar (SAS), which produces reflectivity, seabed depth, and coherence as three channels of information. We describe how the individual channels can be combined by using different coloring schemes and transforms, with example code in matlab. We show example images collected by a HUGIN autonomous underwater vehicle carrying an interferometric SAS. 

Time and place: Mar. 28, 2017 12:15 PM1:00 PM, DSB-labben

Lunch-seminar as part of INF5410/9410.

 

Jørgen Grythe,

Squarehead Technology AS

Time: Mar. 23, 2017 12:00 PM1:00 PM

Many complex media of great practical interest, such as in medical ultrasound and sediment acoustics, display an attenuation that increases with a power law as a function of frequency. Usually measurements can only be taken over a limited frequency range, while fractional wave equations model attenuation over all frequencies. There is therefore some freedom in how the models behave outside of this limited interval, and many different fractional wave equations have been proposed.

In addition, it is desirable that a wave equation models physically viable media and for that two conditions have to be satisfied. The first is causality, and the second is a criterion that comes from thermodynamic considerations and implies that the relaxation modulus is a completely monotonic function. The latter implies that attenuation asymptotically cannot rise faster than frequency raised to the first power. These criteria will be explained and used to evaluate several of the fractional wave equations that exist.

Invited minisymposium presentation at SIAM Computer Science and Engineering conference, Atlanta, Georgia, 27.2-3.3.2017

Time: Mar. 16, 2017 12:00 PM12:45 PM

Jun will present the paper in a short seminar (10-15 minutes):

Chen, W., Fang, J., Pang, G., & Holm, S. (2017). Fractional biharmonic operator equation model for arbitrary frequency-dependent scattering attenuation in acoustic wave propagationThe Journal of the Acoustical Society of America141(1), 244-253.

Time: Mar. 9, 2017 12:15 PM1:00 PM

Title: Can the intracranial pressure waveform be non-invasively estimated from the central aortic waveform?

Presenter: Karen Brastad Evensen

Affiliation: DSB-group (Digital signal processing and image analysis).

Abstract:

Time and place: Feb. 16, 2017 12:15 PM1:00 PM, DSB-lab

Title: Acoustic imaging of sparse sources with Orthogonal Matching Pursuit and clustering of basis vectors.

Presenter: Trond Bergh

Affiliation: DSB-group (Digital signal processing and image analysis) / Squarehead

Abstract: This talk is to be presented at the Int Conf Acoust Speech Sign Proc New Orleans, March 2017. 

We have devised a greedy method for finding solutions to the sparse Deconvolution Approach for the Mapping of Acoustic Sources inverse problem using a variant of Orthogonal Matching Pursuit. The algorithm has two stages, wherein the first stage consists of selecting a subset of the basis vectors iteratively via a regularized inverse of the point spread function, and the second stage consists of constructing point source solutions using this basis subset and its coefficients via hierarchical agglomerative clustering. We have evaluated the algorithm on both synthetic and real data, and show that the overall accuracy in terms of direction of arrival and reconstructed source power is better than four other state of the art methods.

Time and place: Feb. 9, 2017 12:15 PM12:45 PM, DSB-lab

Title: Speckle tracking in ultrasound elastography

Presenter: Elisabeth Ramsdal

Affiliation: DSB-group (Digital signal processing and image analysis).

Abstract:

Time and place: Jan. 26, 2017 12:15 PM1:00 PM, DSB-lab

Title: The effect of seismic source variations on 4D seismic data (Ocean Bottom Cable).

Presenter: Antoine Blachet

Affiliation: DSB-group (Digital signal processing and image analysis).

Abstract: Study of the potential impact on 4D seismic repeatability of subtle changes in source signature and directivity of towed marine airgun source arrays.

Time and place: Jan. 19, 2017 12:15 PM1:00 PM, DSB-lab

Title:  Analysis of sub-techniques in classical cross-country skiing by employing machine learning algorithms on micro sensor data

Presenter: Ole Marius Hoel Rindal

Affiliation: DSB-group (Digital signal processing and image analysis).

Abstract: This presentation was held at the International Congress On Science And Skiing in St. Anton Austria in December 2016. The topic is on automatic identification of sub-techniques in cross-country skiing by using machine learning algorithms on data from inertial measurement units attached to the skier's body.