introduction to computer visioncs.brown.edu/courses/cs143/2009/lecture3.pdf · cs143 intro to...
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©Michael J. Black CS143 Intro to Computer Vision
Introduction to Computer Vision
Michael J. Black
Sept 2009
Lecture 3: Introduction
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©Michael J. Black
Tutorials
Matlab tutorial:
Sunlab (1st 3 rows)
Monday and Tuesday 7-8 pm
Linear Algebra tutorial:
CIT 219 Wednesday and Thursday 7-8 pm
CS143 Intro to Computer Vision 2008
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©Michael J. Black
Office hours
Michael: CIT 521
Mondays 4pm
Thursdays 3pm
Peng, CIT 271: Monday 7-9 pm
Tim: Wednesday 4-6 pm
CS143 Intro to Computer Vision
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©Michael J. Black
Assignment 1
• Parts 1 (pyramids) & 2 (edges and
derivative filters) out of 4 parts out today
• 1&2 Due Wed Sept 23.
CS143 Intro to Computer Vision 2008
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©Michael J. Black
For next class
CS143 Intro to Computer Vision
Reading: Ch 3.2.1 Linear Filtering – Wednesday
Background: 2.3.1 (sampling and aliasing), 3.3
intro (Fourier transform)
Reading ahead: 3.4.1, 3.4.2 (interpolation &
pyramids)
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©Michael J. Black
Applied Math seminar
http://www.dam.brown.edu/ptg/seminar.html
• Wednesdays at noon, 182 George Street,
Room 110
• The outside vision speakers this semester
are Ce Liu (10/14) and Antonio Torralba
(11/6). N
CS143 Intro to Computer Vision
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©Michael J. Black
Imageworld digest
• Lots of job postings, PhD positions, postdoc
positions, faculty positions and conferences.
• http://lists.diku.dk/mailman/listinfo/
imageworld
CS143 Intro to Computer Vision
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©Michael J. Black
Help with a research project?
http://cslab6g.cs.brown.edu:3000/
shape_games/new?
shape_game[type]=OddManOutGame&sha
pe_game[name]=run1&shape_game[questio
n_set_id]=4
CS143 Intro to Computer Vision
Play the body shape similarity game.
View 3 bodies and say which two are most alike.
Full game takes about 20 min. Have to be inside Brown.
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©Michael J. Black
Bringing Pictorial Space to Life
CS143 Intro to Computer Vision
Antonio Criminisi:
http://research.microsoft.com/pubs/67260/criminisi_chart2002.pdf
http://research.microsoft.com/en-us/um/people/antcrim/
acriminisi_singleviewmetrology.wmv
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©Michael J. Black CS143 Intro to Computer Vision
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©Michael J. Black CS143 Intro to Computer Vision
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©Michael J. Black CS143 Intro to Computer Vision
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©Michael J. Black
Automatic Photo Pop-Up
CS143 Intro to Computer Vision 2008
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©Michael J. Black
Popup
• http://www.cs.uiuc.edu/homes/dhoiem/
projects/popup/index.html
CS143 Intro to Computer Vision 2008
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©Michael J. Black
Make3D
• Saxena and Ng. Submit your photo.
• Have a look:
http://make3d.stanford.edu/images/showall
CS143 Intro to Computer Vision 2008
http://make3d.stanford.edu/
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©Michael J. Black
Goals for Today
CS143 Intro to Computer Vision
Continue with introduction.
What does it mean to see and how do we do it?
How can we make this formal (mathematical
and computational)?
Consider a case study of object recognition – in
class “group” work.
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©Michael J. Black CS143 Intro to Computer Vision
Computer Vision
- take all the cues of artists and “turn them around”
- exploit these cues to infer the structure of the world
- need mathematical and computational models of
these cues
- sometimes called “inverse graphics”
First pass at a definition:
Idea 1: model physics of image formation and find the best “model”
that matches the image observations.
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©Michael J. Black CS143 Intro to Computer Vision
Crater illusion
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©Michael J. Black CS143 Intro to Computer Vision
Very powerful effect
Liu and Todd, Vision Research 2004.
Idea 2: we need more than just a model of the physics of image
formation. Need to model something about our prior experience
with the world.
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©Michael J. Black CS143 Intro to Computer Vision
Light and
shadows
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©Michael J. Black CS143 Intro to Computer Vision
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©Michael J. Black CS143 Intro to Computer Vision
Is this an
illusion?
Vision: not just
“measurement” –
interpretation.
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©Michael J. Black
Combination of cues
CS143 Intro to Computer Vision
Dan Kersten, http://vision.psych.umn.edu/users/kersten/kersten-lab/shadows.html
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©Michael J. Black CS143 Intro to Computer Vision
Hartung, B., & Kersten, D. (2002). Distinguishing Shiny from Matte.
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©Michael J. Black
Does our brain “represent” the
physical truth?
CS143 Intro to Computer Vision
R. Rensink
• change blindness movies
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©Michael J. Black
Does our brain “represent” the truth?
CS143 Intro to Computer Vision
R. Rensink
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©Michael J. Black
Does our brain “represent” the truth?
CS143 Intro to Computer Vision
R. Rensink
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©Michael J. Black
Does our brain “represent” the truth?
CS143 Intro to Computer Vision
R. Rensink
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©Michael J. Black
Does our brain “represent” the truth?
CS143 Intro to Computer Vision
R. Rensink