Thank you very much for this introduction. Actually I am almost blushing after hearing
all of this and I'm also amazed to see so many of you here listening to this presentation.
Wow, thank you very much for coming. I hope you enjoy the presentation so I'm trying to
do my best here and I want to show you a bit about the research that we've been
doing in the last couple of years and in particular I want to introduce the
technique of known operator learning because sometimes there's things that
are being tackled right now in machine learning where we already know more
about the problem that can be integrated and sometimes it makes sense actually to
reuse that prior knowledge. So I'll give a short introduction if possible, if not.
I'll give a short introduction. I'll not remote control but I'll press buttons
instead. So the well in deep learning we see quite a few things happening and
there's many many many things that are being tackled and most of the things
that are being tackled are perceptual problems. Things that you can see and
typically you need humans to do it and what people are trying to solve in these
new deep machine learning algorithms is try to process data and then extract
some information from that and I want to show some example. This is based on a
reinforcement learning technique and here a colleague, so it's a collaboration
with Siemens actually, they tried to detect anatomical landmarks in whole
body CT datasets and the idea that they used is that they formulated as a kind
of game problem where you look at some patch of a volume and try to decide to
go into the right direction in order to detect that anatomical landmark. Somehow
motivated by how a radiologist looks at an image, you know, he looks for
anatomical structures that he knows and then follows towards the network he's
interested in and here we try to model this as a game approach and we use an
agent that is kind of playing this game to detect the landmarks. We're using a
multi-resolution scheme here so we gradually zoom into the image in order
to refine finding that landmark and the nice idea about this whole process is
that it's really quick. You don't have to process the entire volume but you only
process relevant parts towards finding that certain landmark. So this approach
is very fast. We can detect 200 anatomical landmarks in approximately two
seconds on a full body CT. So that's pretty quick. The other thing is it's not
just finding landmarks but we also get some kind of well interpretation because
we find the path towards that anatomical landmark and we can see that it follows
anatomical structures that make sense in order to figure out where that landmark
is located. A cool thing about this is if you're missing a part of the anatomy
then this agent will try to leave the volume so there's no hip bone in this
volume and the agent tries to run out of the volume at the very bottom. So this is
a nice approach and you know it has a couple of advantages compared to other
approaches if you consider traditional liver segmentation tasks they would
segment the liver everywhere also in a head volume. With this one we get some
additional trust but we don't really understand how the agent makes the
decisions. We have this deep network that is taking some input and is deriving
some reaction from it. So it's very hard to interpret this and we see that these
deep learning techniques they're not only used for these perceptual problems
but more and more they're being applied towards all kinds of problems. One
particular one that I want to show here is an application where they try to
complete CT reconstruction images. So what you see here is an incomplete CT scan
and it's a it's you could say a partial reconstruction. The image here on the
left-hand side has been reconstructed only from 120 degrees of rotation which
means it's an incomplete scan and now what people have been investigating is
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00:44:56 Min
Aufnahmedatum
2020-01-09
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2020-01-09 20:29:03
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