George Ioannakis

RETRIEVAL 3D : an on-line content-based retrieval performance evaluation tool

Performance benchmarking is an absolute necessity when attempting to objectively quantify the performance of content-based retrieval methods. For many years now, a number of plot-based and scalar-based measures in combination with benchmark datasets have already been used in order to provide objective results. In this work, we present the first version of an integrated on-line content-based retrieval evaluation tool, named RETRIEVAL3D, which can be used in order to quantify the performance of a retrieval method. The current version of the system offers a set of popular performance measures that can be accessed through a dynamic visualisation environment. The user is able to upload retrieval results using different input data structures (e.g. binary ranked lists, floating point ranked lists, dissimilarity matrices and groundtruth data) that are already encountered in the literature including the SHREC competition series. Moreover, the system is able to provide evaluation mechanisms for known within the retrieval research community benchmark datasets. It offers performance measures parameterisation that enables the user to determine specific aspects of the evaluated retrieval method. Performance reports archiving and downloading are some of the systems user-oriented functionalities.

Partial shape queries for 3D object retrieval

Despite numerous recent efforts, 3D object retrieval based on partial shape queries remains a challenging problem, far from being solved. The problem can be defined as: given a partial view of a shape as query, retrieve all partially similar 3D models from a repository. The objective of this track is to evaluate the performance of partial 3D object retrieval methods, for partial shape queries of various scan qualities and degrees of partiality. The retrieval problem is often found in cultural heritage applications, for which partial scans of objects query a dataset of geometrically distinct classes.

RETRIEVAL—An Online Performance Evaluation Tool for Information Retrieval Methods

Performance evaluation is one of the main research topics in information retrieval. Evaluation metrics are used to quantify various performance aspects of a retrieval method. These metrics assist in identifying the optimum method for a specific retrieval challenge but also to allow its parameters fine-tuning in order to achieve a robust operation for a given set of requirements specification. In this work, we present RETRIEVAL, a Web-based integrated information retrieval performance evaluation platform. It offers a number of metrics that are popular within the scientific community, so as to compose an efficient framework for implementing performance evaluation. We discuss the functionality of RETRIEVAL by citing important aspects such as the data input approaches, the user-level performance metrics parameterization, the evaluation scenarios, the interactive plots, and the performance reports repository that offers both archiving and download functionalities.

The Orion Pottery Repository – A Publicly Available 3D Objects’ Benchmark Database with Texture Information

Performance evaluation is one of the main research topics in information retrieval. Evaluation metrics in combination with benchmark datasets (groundtruth) are used to quantify various performance aspects of a retrieval algorithm. In this paper, we present the Orion Pottery Repository, a publicly available and domain specific benchmark database. It is based on open source technologies and contains a total of 160 textured 3D digital replicas of ancient Greek pottery. The dataset offered through the repository can be used for performance evaluation experiments of 3D data retrieval algorithms. Orion’s content has been classified according to a pottery shape categorization defined by an in-house developed thesaurus. The repository provides mechanisms that allow a wide range of metadata handling that are based on the CARARE metadata schema which among others it offers the ability to include information related to digitization procedures and their properties.

3D object spatial- consistent texture maps appropriate for 2D image processing

The aim of this work is to generate a spatial-consistent UV maps of a 3D objects texture suitable for 2D image processing algorithms. An approach to produce such a fully spatially consistent UV mapping suitable for image processing based on the planar parameterisation of the mesh is presented. The mesh of a 3D model is parametrised onto a unit square 2D plane using computational conformal geometry techniques. The proposed method is genus independent, due to an iterative 3D mesh cutting procedure. The selection of the initial seed vertex for the mesh-cut is not essential for the parameterisation of the geometry, however it affects heavily the appearance of the obtained texture map. In this work we attempt to determine such a seed vertex, in order the UV map to be suitable for image processing. Having the texture of a 3D model depicted on a spatially continuous two dimensional structure enables us to efficiently apply well known image processing based techniques and algorithms. Our method is applied on a 3D digital replica of an ancient Greek Lekythos vessel.

Applying conformal geometry for creating a 3D model spatial-consistent texture map

The aim of this research is to achieve spatial consistency of the UV map. We present an approach to produce a fully spatially consistent UV mapping based on the planar parameterisation of the mesh. We apply our method on a 3D digital replica of an ancient Greek Lekythos vessel. We parameterise the mesh of a 3D model onto a unit square 2D plane using computational conformal geometry techniques. The proposed method is genus independent, due to an iterative 3D mesh cutting procedure. Having now the texture of a 3D model depicted on a spatially continuous two dimensional structure enables us to efficiently apply a vast range of image processing based techniques and algorithms.