[Colloquium] TTI-C Talk: Devi Parikh, CMU

[Julia MacGlashan]

REMINDER

When:             Tuesday, April 21st @ 11:00am (lunch will be provided
after talk)

Where:            6045 S Kenwood Ave, TTI-C Conference Room #526 (5th Floor)

Who:               Devi Parikh, Carnegie Mellon University

Title:                The Role of Context in Image Understanding: When, For
What, and How?


A key problem in computer vision is image understanding, which we define as
the task of recognizing objects in the scene, and perhaps the scene category
itself. Traditionally, object recognition has been accomplished by
considering only the information within the object to be recognized.
Incorporating contextual information, i.e., information outside the
boundaries of the object, for enhanced recognition has received significant
attention in recent works. In this talk, we take a closer look at the role
of context. Specifically, we ask three questions. First: When is context
really helpful? We show, through computer vision experiments as well as
human studies, that context provides improvements in recognition
performances only when the appearance information is weak (such as in low
resolution images or in the presence of occlusion). Second: For what tasks
can contextual information be leveraged? We show that apart from high- level
tasks of object recognition and detection, contextual information can be
effectively leveraged for low level tasks as well, such as identifying
salient or representative patches in an image.  
Lastly (the focus of the talk), How can context be learnt? Or alternatively,
how much contextual information can be extracted in an unsupervised manner?
We propose a unified hierarchical representation for contextual interactions
or spatial patterns among visual entities at all levels, from low-level
features to parts of objects, objects, groups of objects and ultimately the
entire scene. We present results of our approach on a variety of datasets
such as object categories, street scenes and natural scene images.

Contact:          Greg Shakhnarovich, TTI-C		greg at tti-c.org
834-2572


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