[Colloquium] Larsson/Dissertation Defense/Jun 9, 2017

[Margaret Jaffey via Colloquium]

       Department of Computer Science/The University of Chicago

                     *** Dissertation Defense ***


Candidate:  Gustav Larsson

Date:  Friday, June 9, 2017

Time:  3:00 PM

Place:  TTIC 526

Title: Discovery of Visual Semantics by Unsupervised and
Self-Supervised Representation Learning

Abstract:
The success of deep learning in computer vision is rooted in the
ability of deep networks to scale up model complexity as demanded by
challenging visual tasks. As complexity is increased, so is the need
for large amounts of labeled data to train the model. This is
associated with a costly human annotation effort. To address this
concern, with the long-term goal of leveraging the abundance of cheap
unlabeled data, we explore methods of unsupervised "pre-training." In
particular, we propose to use self-supervised automatic image
colorization.

We show that traditional methods for unsupervised learning, such as
layer-wise clustering or autoencoders, remain inferior to supervised
pre-training. In search for an alternative, we develop a fully
automatic image colorization method. Our method sets a new
state-of-the-art in revitalizing old black-and-white photography,
without requiring human effort or expertise. Additionally, it gives us
a method for self-supervised representation learning. In order for the
model to appropriately re-color a grayscale object, it must first be
able to identify it. This ability, learned entirely self-supervised,
can be used to improve other visual tasks, such as classification and
semantic segmentation. As a future direction for self-supervision, we
investigate if multiple proxy tasks can be combined to improve
generalization. This turns out to be a challenging open problem. We
hope that our contributions to this endeavor will provide a foundation
for future efforts in making self-supervision compete with supervised
pre-training.

Gustav's advisors are Prof. Yali Amit and Prof. Gregory Shakhnarovich

Login to the Computer Science Department website for details,
including a draft copy of the dissertation:

 https://www.cs.uchicago.edu/phd/phd_announcements#larsson

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Margaret P. Jaffey            margaret at cs.uchicago.edu
Department of Computer Science
Student Support Rep (Ry 156)               (773) 702-6011
The University of Chicago      http://www.cs.uchicago.edu
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=