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Artificial vision applications, such as object detection in natural images and automatic segmentation of medical acquisitions, rely on models that interpret the visual information provided to a computer. The model provides a compromise between the support given by the observations and the prior domain knowledge. This course is concerned with the two computational problems that arise when using such models in practice.
Inference (Energy Minimization):
Given a visual observation (for example, an image or an MRI scan), we are interested in estimating its most likely interpretation (i.e. the location of all the objects in the image, or the segments of the MRI scan) according to the model. While the problem cannot be solved optimally, we will describe state of the art approximate algorithms that provide very accurate solutions in practice. While the theoretical properties of the algorithms will be discussed briefly, the main emphasis will be on their application.
Given a set of training samples consisting of inputs and their desired outputs, (for example, images and the location of the objects, or MRI scans and their segmentations) we would like to estimate a model that is suited to the task at hand. We will show how the problem of learning a model can be formulated as empirical risk minimization. Furthermore, we will present efficient algorithms for solving the corresponding optimization problem.
1: Introduction to artificial vision with discrete graphical models
Lecture 2: Reparameterization and dynamic programming
Lecture 3: Minimum cut based inference
Lecture 4: Maximum flow and minimum cut
Lecture 5: Belief propagation
Lecture 6: Linear programing and duality
Lecture 7: Dual decomposition and higer order graphs
Lecture 8: Parameter learning
We will present the state of the art energy minimization algorithms that are used to perform inference in modern artificial vision models: that is, efficient methods for obtaining the most likely interpretation of a given visual input. We will also cover the popular max-margin framework for estimating the model parameters using inference.