ImPhys Seminar

03 April 2017 | 12:45 - 13:30
plaats: Lecture Room E
by webmaster ImPhys

Lecturer: Marco Mout, MSc (ImPhys-Optics) and Dr. ir. Arjan den Dekker (Universiteit van Antwerpen)

'A ray-based method for diffraction simulations'(Marco Mout)

When simulating imaging systems we are in general interested in both the effects of aberrations and of diffraction. Usually the former are simulated using geometrical optical methods, whereas the later require wave optical simulations. To account for diffraction effects in ray tracing, we have developed a method based on the Huygens-Fresnel principle. It initiates secondary sources at diffracting surfaces (e.g., the aperture stop) and propagates their fields using ray tracing. We thereby simulate both aberrations and (multiple) diffraction within a single ray-tracing framework.  

'Super-resolution reconstruction of magnetic resonance images' (Arjan den Dekker)

Magnetic resonance imaging (MRI) suffers from an inherent trade-off between spatial resolution, acquisition time, and signal-to-noise ratio (SNR). In clinical practice, the direct acquisition of 3-D isotropic high-resolution (HR) images is often not feasible since it results either in unacceptably long acquisition times or a poor SNR. As a consequence, most MRI studies settle for either anisotropic or isotropic low resolution (LR) images.Fortunately, recent work has shown that super-resolution reconstruction (SRR) methods are able to improve the trade-off mentioned above. SRR methods reconstruct an HR 3-D isotropic image from a set of multi-slice 3-D anisotropic images with a low through-plane resolution, where each LR image is sampled in a different fashion. Previously, our group proposed a generic SRR method for anatomical MRI. More recently, this methodology was successfully extended to diffusion MRI and relaxometry. As will be demonstrated in this talk, experimental results show a significant increase in spatial resolution while preserving a high SNR for a fixed acquisition time.

 

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