Geometric Inference for Probability Distribution
Description
Data often comes in the form of a point cloud sampled from an unknown compact subset of Euclidean space. The general goal of geometric inference is then to recover geometric and topological features (Betti numbers, curvatures,...) of this subset from the approximating point cloud data. In recent years, it appeared that the study of distance functions allows to address many of these questions successfully. However, one of the main limitations of this framework is that it does not cope well with outliers nor with background noise. In this talk, we will show how to extend the framework of distance functions to overcome this problem. Replacing compact subsets by measures, we will introduce a notion of distance function to a probability distribution.
These functions share many properties with classical distance functions, which makes them suitable for inference purposes. In particular, by considering appropriate level sets of these distance functions, it is possible to associate in a robust way topological and geometric features to a probability measure. If time permits, we will also mention a few other potential applications of this framework.
| Slides | |
| 0:00 | Geometric Inference for Probability distributions |
| 0:01 | Motivation |
| 1:03 | Geometric inference |
| 4:21 | Distance functions for geometric inference |
| 7:52 | Stability properties of the offsets |
| 10:16 | The problem of outliers |
| 12:32 | The three main ingredients for stability |
| 16:11 | Replacing compact sets by measures |
| 17:42 | Distance between measures |
| 20:51 | Wasserstein distance |
| 23:18 | The distance to a measure |
| 24:56 | Unstability of µ -> σµ,m |
| 27:13 | The distance function to a measure. (1) |
| 29:08 | The distance function to a measure. (2) |
| 29:13 | The distance function to a measure. (1) |
| 29:16 | The distance function to a measure. (2) |
| 30:26 | 1-Concavity of the squared distance function |
| 30:40 | Proposition |
| 30:43 | 1-Concavity of the squared distance function |
| 30:48 | Proposition |
| 31:19 | Another expression for dµ,m0 (1) |
| 32:45 | Another expression for dµ,m0 (2) |
| 34:36 | Theorem |
| 36:18 | Consequences of the previous properties |
| 36:30 | Example : square with outliers (1) |
| 36:58 | Example : square with outliers (2) |
| 37:03 | Example : square with outliers (1) |
| 37:07 | Example : square with outliers (2) |
| 37:30 | A 3D example |
| 38:27 | A reconstruction theorem |
| 39:44 | k-NN density estimation vs distance to a measure (1) |
| 40:32 | k-NN density estimation vs distance to a measure (2) |
| 40:38 | k-NN density estimation vs distance to a measure (1) |
| 40:52 | k-NN density estimation vs distance to a measure (2) |
| 41:28 | k-NN density estimation vs distance to a measure (3) |
| 41:47 | k-NN density estimation vs distance to a measure (4) |
| 42:42 | Pushing data along the gradient of dµ,m0 (1) |
| 44:22 | Pushing data along the gradient of dµ,m0 (2) |
| 45:46 | Take-home messages |
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.
Related content
Link this page
Would you like to put a link to this lecture on your homepage?Go ahead! Copy the HTML snippet !





