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Program (remove abstracts)

 
   
09:15 - 09:45 Refreshments and tagging
   
09:45 - 10:00 Greetings :
Ohad Ben-Shahar, Department of Computer Science
Prof. Rivka Carmi, BGU President
   
10:00 - 10:50 Shimon Ullman, Weizmann Institute
Recognizing objects and natural classes
I will describe a computational scheme which learns to recognize new object categories from image examples. Starting with a collection of images illustrating examples of a category such as 'face', 'car', or 'horse', the model constructs a category representation, and then uses it to identify novel members of the category. The approach is based on representing shapes within a category by a hierarchy of shared sub-structures called fragments, selected by maximizing the information delivered for categorization. I will present results of applying the model to natural object categories, and discuss relationships between the model and parts of the primate visual system involved in object perception.
   
10:50 - 11:40 Its'hak Dinstein, Ben-Gurion University
Binarization, skew detection, character extraction, and writer identification in historical Hebrew calligraphy documents
We present our work on the paleographic analysis and recognition system intended for processing of historical Hebrew calligraphy documents. One of the goals is to analyze documents of different writing styles in order to identify the locations, dates, and writers of test documents. We discuss our approach to binarization, skew detection, and writer classification. Results of automatic extraction of pre-specified letters using the erosion transform are presented. We further propose and test topological features for handwriting style classification based on a selected subset of the Hebrew alphabet.

Joint work with Klara Kedem, Itay Bar-Yoseph, Amir Egozi, and Isaac Beckman, Ben Gurion University.
   
11:40 - 12:30 Freddy Bruckstein, Technion
On variational methods for image analysis
This talk will focus on variational methods in signal and image processing raising questions on the choice of functionals that are optimized for various tasks. It is argued that the selection of functionals is more of an art than a science. Several examples will be discussed from denoising to the Estimation of optic flow in video streams.
   
12:30 - 13:30 Lunch
   
13:30 - 13:40 Greetings :
Prof. Moti Hershkowitz, Vice-President and Dean for Research and Development
   
13:40 - 14:30 Nir Sochen, Tel Aviv University
Segmentation from Descartes to Kant
We will treat the segmentation problem as an epistemological question and hopefully illustrate complicated philosophical arguments with "simple" segmentation problems. In particular we will discuss texture segmentation, prior-shape segmentation and dynamic labeling approaches via the variational and level-set frameworks.
   
14:30 - 15:20 Ohad Ben-Shahar, Ben-Gurion University
Does it make any sense to move your head when you look at a mirror?
The image of a curved, specular (mirror-like) surface is a distorted reflection of the environment. Although the recovery of such specular shape from its image appears futile without some knowledge of the environment, the goal of this work is to develop a theoretical and practical framework for solving this shape inference problem when the environment is completely unknown. We show that although this general problem is severely ill-posed, allowing relative object-environment motion induces a dense specular flow in the image plane which can be related to surface shape through a pair of coupled non-linear partial differential equations that are independent on the environment content. We examine the qualitative and geometric properties of these equations and present analytic and numerical methods for recovery of specular shape in several cases.

Joint work with Yair Adato, Ben Gurion University, and Yuriv Vasilyev and Todd Zickler, Harvard University.
   
15:20 - 15:40 Coffee break
   
15:40 - 16:30 Amnon Shashua, Hebrew University
The Role of multi-linear constrained Factorization in Image Coding, Clustering, and Visual Recognition
I will present a bird's eye view of novel connections between the task of factorizing measurements arranged in multi-way arrays (tensors in general) under certain convex constraints to core problems in Learning and Visual processing. A general low-rank factorization under simplex constraints corresponds to a latent class model solution, and a super-symmetric factorization corresponds to the general problem of achieving a soft clustering assignment over hypergraph representations. A mixture of the general and super-symmetric arrays corresponds to a "latent clustering" model in which the value of the hidden variable determines the pairwise affinities between data points. The framework has been applied to areas of image coding, multi-body segmentation, "bag of words" inference tasks, and multi-class visual recognition using shared fragments.
   
16:30 - 17:20 Daniel Keren, Haifa University
Image Detection without Negative Examples
In a typical image detection system, a classifier (e.g. neural net or support vector machine) is supplied with positive and negative examples, and it constructs a classification rule using these examples. In this talk, I will describe a simple method to replace the negative examples with a probability distribution. In some cases, notably when the number of positive examples is small, it performs better than the standard classifier.

Joint work with Rita Osadchy and Tali Buchnik, Haifa University.
   
 

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Last modified: 31 May 2007