Scientific Visualization and Computer Graphics > CS > BI > FSE > RUG

# Jasper van de Gronde

• room number: 491 (Bernoulliborg, building 5161)
• e-mail: j.j.van.de.gronde rug.nl

## Research interests

I am interested in all sorts of image processing topics, including compressed sensing, linear and morphological filters, and deep learning, with a special interest in applications on large/high-dimensional and non-scalar data. Making proper use of vector- or tensor-valued data, possibly as an intermediate step, also interests me greatly, as does the interplay between (mostly) linear approaches and morphological approaches. My PhD thesis was on morphological operators for tensor images, exploring shape and structure in movement and direction dependence. I defended my thesis on 30 June 2015, and am currently a post-doc.

Tensor images (or volumes) are just like ordinary images or volumes, except that at each point we have a vector or matrix (tensors are essentially a generalization of vectors and matrices). To visualize a tensor image with matrices at each position, we typically use "glyphs": for each position a small glyph is drawn whose shape represents the matrix (S). The glyph is often a unit sphere deformed in such a way that each vector v on the unit sphere is given the magnitude v.(S.v). Below you can interact with a live demonstration of this technique (requires a WebGL capable browser, I recommend Firefox, and possibly some patience):

 WebGL based demonstration of tensor field glyphs Rotating Click and drag. Zooming Press +/- or use mousewheel. Glyph resizing Hold Ctrl and zoom. Press 'u' to make all glyphs approximately the same size. Cutting plane Press 'c'. The plane will be parallel to the screen and through the origin. In this case, the matrices describe stresses at atomic positions in a nanowire (courtesy of S.S.R. Saane, Micromechanics group, RuG). Blue shows positive values(/radii), while orange shows negative values.

## Demos

Apart from the rendering above, here is some more code you can try out both in the browser and using Node.js:

There are also some demos that can only be run off-line:

Various projects not (necessarily) associated with a particular publication can be found on Github (also see the SciJS repository).