Introduction

After the success of SHREC - 3D Shape Retrieval Contest 2006, the Network of Excellence AIM@SHAPE is taking the initiative to organize a sequel. The general objective is to evaluate the effectiveness of 3D-shape retrieval algorithms. The contest is organized in conjunction with the SMI'07 conference (Shape Modeling International), where the evaluation results will be presented.

What is relevance feedback?

The most powerful technique in improving retrieval adequacy, apart from devising better low-level descriptors, is the use of Relevance Feedback (RF) algorithms. In RF schemes, the user becomes an active part of the retrieval system. S/He supplies the system with a query and some scores for relevant and non-relevant examples. Then, the system refines the search and responses with a new list of objects that contain more similar to the user query, objects. Traditional RF techniques try to re-weight the various dimensions of the feature vectors or apply learning algorithms. Lately, a few RF methods have been introduced, which try to combine low-level and high-level characteristics in order to move the database objects, so that the objects form semantic clusters in a multidimensional vector space.

Description of the track

The geometric method which will be used is the one described in:
M. Kazhdan, T. Funkhouser, and S. Rusinkiewicz, “Rotation invariant spherical harmonic representation of 3D shape descriptors”
in Proceedings of the Eurographics Symposium on Geometry Processing, pp. 156–164, Aachen, Germany, June 2003.

The executables of this method can be found in: http://shape.cs.princeton.edu/benchmark/

Participants are called to provide executables combining the aforementioned geometric method with their RF methods. They will be tested on the following databases:

• ITI Database (http://shrec.iti.gr/download.html)
• Princeton Shape Benchmark (http://shape.cs.princeton.edu/benchmark/)

The evaluation will be done by means of Precision-Recall diagrams. Every object of the database will be used as query for 10, 100 and 300 times, while the first 10, 20 or 40 retrieved objects will be given scores each time. For each combination of the above values, a Precision-Recall diagram must be extracted. The contest concern both ground truth datasets.

A description of input and output parameters of the executables can be found in http://shrec.iti.gr/executables.html.

Registration

Participants can register simply by email: daras"@"iti.gr, onaso"@"iti.gr

Deadlines

1. Participants must register before 30.3.2007.
2. Participants are welcome to send 3D models of their choice, which they want to be used in the contest, before 12.4.2007. The 3D models should be either in vrml or in .off format and consist of a single object (not a scene). Each 3D model should belong to one of the pre-defined categories of the aforementioned databases.
3. The executables must be sent until 16.4.2007.

Organization

The SHREC contest is an initiative of the Network of Excellence AIM@SHAPE. The Relevance Feedback Track is organized by the Informatics and Telematics Institute / Centre for Research and Technology Hellas and is supported by the VICTORY EU project (http://www.victory-eu.org).