Bio-medical Ontologies Maintenance and Change Management

Multimedia Medical Databases 73
Queries Information
Query’s
characteristics
Processing and
characteristics extractions
Similar information
retrieval
Similarity
measurement
Fig. 1.1. General Model for an information retrieval system
In the presented model, two of the most important features, are:
• Records indexing in the database
• Similarity measurement between query and the information in the database
The indexing is defined as a mechanism that reduces the searching space
without losing important information. Like in the traditional databases management
systems, indexing is necessary to increase the speed of the retrieval operation. It is
also a very important operation in the multimedia databases where large amount of
information need to be stored. The retrieval operation based on direct comparison
between multimedia information records and the query, it is a slow process. As a
result, it is important for multimedia information to have attributes that store the
relevant information. These attributes must be compact and fast when they are used
for retrieval. It is hard to find these attributes because multimedia information does
not have a specific syntax or semantic.
The second important feature for information retrieval is the measure of
similarity. The attributes that will be used for comparing must have properties like:
• Easy computation
• Correspondence to the human thinking
The second property is very important because the multimedia information retrieval
is based on similarity and not on exact matching. The results of the retrieval
are returned to the user in decreasing order of the similarity. All returned
objects are considered to be relevant or similar to the query object. That is the reason
why it is ideally considered that the similarity computing to be according to
the human mind: the object considered to be similar by the human mind must be
similar according to the similarity computing.
1.2 Content-Based Visual Query – Problem Definition
Indexed
information
Pre-processing
and indexing
The objective of the content-based visual query is to search and retrieve in an
efficient manner those images from the database that are most appropriate to the