I agree that it might make more sense to model our needs more directly
instead of trying to squeeze it into the schema we normally use for text
processing. But at the same time I would of course like to avoid having
to reimplement many of the things that are already available when using
AnnotationBase.
For the cross-view indexing issue I was thinking of creating individual
views for each modality and then a merged view that just contains a
subset of annotations of each view, and on which we would do the
cross-modal reasoning.
I just looked again at the GaleMultiModalExample (not much there,
unfortunately) and saw that e.g. AudioSpan derives from AnnotationBase
but still has float values for begin/end. I would be really interested
in learning more about what was done in GALE, but it's hard to find any
relevant information...
Thanks,
Jens
On 04/12/13 20:16, Marshall Schor wrote:
Echoing Richard,
1) It would perhaps make more sense to be more direct about each of the
different types of data. UIMA "built-in" only the most "popular" things - and
Annotation was one of them.
Annotation derives from Annotation-base, which just defines an associated Sofa /
view.
So it would make more sense to define different kinds of highest-level
abstractions for your project, related to the different kinds of views/sofas.
Audio might entail a begin / end style of offsets; Images might entail a pair
x-y coordinates, to describe a (square) subset of an image. Video might do
something like audio, or something more complex...
UIMA's use of the AnnotationBase includes insuring that when you add-to-indexes
(an operation that implicitly takes a "view" - and adds a FS to that view), that
if the FS is a subtype of AnnotationBase, then the FS must be indexed in the
associated view to which that FS "belongs"; if you try to add-to-index in a view
other than the one the FS was created in, you get this kind of error:
Error - the Annotation "{0}" is over view "{1}" and cannot be added to indexes
associated with the different view "{2}".
The logic behind this restriction is: an Annotation (or, more generally, an
object having a supertype of AnnotationBase) is (by definition) associated with
a particular Sofa/View, and it is more likely that it is an error if that
annotation is indexed with a sofa it doesn't belong with.
Of course, Feature Structures which are not Annotations (or more generally, not
derived from AnnotationBase), can be indexed in multiple views.
2) By keeping separate notions for pointers-into-the-Sofa, you can define
algorithmic mappings for these that make the best sense for your project,
including notions of fuzzyness, time-shift (imagine the audio is out-of-sync
with the video, like lots of u-tube things seem to be), etc.
-Marshall
On 12/4/2013 9:31 AM, Jens Grivolla wrote:
Hi, we're now starting the EUMSSI project, which deals with integrating
annotation layers coming from audio, video and text analysis.
We're thinking to base it all on UIMA, having different views with separate
audio, video, transcribed text, etc. sofas. In order to align the different
views we need to have a common offset specification that allows us to map e.g.
character offsets to the corresponding timestamps.
In order to avoid float timestamps (which would mean we can't derive from
Annotation) I was thinking of using audio/video frames with e.g. 100 or 1000
frames/second. Annotation has begin and end defined as signed 32 bit ints,
leaving sufficient room for very long documents even at 1000 fps, so I don't
think we're going to run into any limits there. Is there anything that could
become problematic when working with offsets that are probably quite a bit
larger than what is typically found with character offsets?
Also, can I have several indexes on the same annotations in order to work with
character offsets for text analysis, but then efficiently query for
overlapping annotations from other views based on frame offsets?
Btw, if you're interested in the project we have a writeup (condensed from the
project proposal) here:
https://dl.dropboxusercontent.com/u/4169273/UIMA_EUMSSI.pdf and there will
hopefully soon be some content on http://eumssi.eu/
Thanks,
Jens
