event thumbnail image
Carnegie Mellon Machine Learning Lunch seminar

Local Minima Free Parameterized Appearance Models

author: Minh Hoai Nguyen, Robotics Institute, School of Computer Science, Carnegie Mellon University

Description

Parameterized Appearance Models (PAMs) (e.g. Eigen-tracking, Active Appearance Models, Morphable Models) are commonly used to model the appearance and shape variation of objects in images. While PAMs have numerous advantages relative to alternate approaches, they have at least two drawbacks. First, they are especially prone to local minima in the fitting process. Second, often few if any of the local minima of the cost function correspond to acceptable solutions. To solve these problems, this paper proposes a method to learn a cost function by explicitly optimizing that the local minima occur at and only at the places corresponding to the correct fitting parameters. To the best of our knowledge, this is the first paper to address the problem of learning a cost function to explicitly model local properties of the error surface to fit PAMs. Synthetic and real examples show improvement in alignment performance in comparison with traditional approaches.

You might be experiencing some problems with Your Video player.
Slides
0:00 Local Minima Free Parameterized Appearance Models
0:46 Image alignment
1:13 Some work in image alignment
1:59 Image alignment as an optimization problem
4:42 Issues of gradient‐based optimization
7:02 Local minima problems in image alignment
8:19 Quadratic cost function part1
8:52 Quadratic cost function part2
9:05 Training data
9:20 Multiple training images
9:55 1st desired property of the cost function
10:22 2nd desired property of the cost function
11:32 Enforcing the 2nd desired property
12:53 The learning problem part1
14:03 The learning problem part2
14:45 Weighted template alignment
15:46 Experiment with the Gaussian
16:05 Error surfaces
16:33 Active Appearance Models (AAMs)
17:14 Energy function in AAMs
18:48 Learning AAM energy function
20:04 Experiments with Multi‐PIE database
20:32 Results of weighted PCA basis
22:07 Summary
22:48 Thank you
23:00 - Questions

Lecture rating

People found this lecture:
Worth seeing
because it is:
 Valuable and informative
Well presented
Easily understandable
Acceptably recorded
You need to login to cast your vote.

Report a problem or upload files

If you have found a problem with this lecture or would like to send us extra material, articles, exercises, etc., please use our ticket system to describe your request and upload the data.
Enter your e-mail into the 'Cc' field, and we will keep you updated with your request's status.

Link this page

Would you like to put a link to this lecture on your homepage?
Go ahead! Copy the HTML snippet !

Write your own review or comment:

make sure you have javascript enabled or clear this field: