Query Output Research Articles

Shape measures for content based image retrieval: A comparison

A great deal of work has been done on the evaluation of information retrieval systems for alphanumeric data. The same thing can not be said about the newly emerging multimedia and image database systems. One of the central concerns in these systems is the automatic characterization of image content and retrieval of images based on similarity of image content. In this paper, we discuss effectiveness of several shape measures for content based similarity retrieval of images. The different shape measures we have implemented include outline based features (chain code based string features, Fourier descriptors, UNL Fourier features), region based features (invariant moments, Zernike moments, pseudo-Zernike moments), and combined features (invariant moments & Fourier descriptors, invariant moments & UNL Fourier features). Given an image, all these shape feature measures (vectors) are computed automatically, and the feature vector can either be used for the retrieval purpose or can be stored in the database for future queries. We have tested all of the above shape features for image retrieval on a database of 500 trademark images. The average retrieval efficiency values computed over a set of fifteen representative queries for all the methods is presented. The output of a sample shape similarity query using all the features is also shown.

Practical enhanced Boolean retrieval: Experiences with the smart and sire systems

During the last decade, studies with the SMART and SIRE systems have pioneered new techniques for improving the effectiveness of Boolean retrieval. Extended Boolean logic, automatic Boolean query construction, and Boolean feedback yield significant improvements according to a variety of experiments with SMART. Ranking of the output of Boolean queries has been shown to be of value with SIRE. Recent efforts have aimed at adapting SMART to allow large scale testing of these advanced retrieval methods. SIRE has been enhanced to include the p-norm scheme for extended Boolean query processing. Implementation and performance details about SMART and SIRE illustrate how commercially available retrieval systems can be improved to use the fruits of these research efforts.