Bio-medical Ontologies Maintenance and Change Management

132 L. Stanescu, D. Dan Burdescu, and M. Brezovan
The user may also assign a relative weight α to each attribute. For example, the
user may weigh the size parameter more heavily than feature value and location in
the query. For multiple regions query, the overall image query strategy consists of
joining the queries on the individual regions in the query image. The join identifies
the candidate target images.
For testing the efficiency of the new method and for comparing the two methods
of implementation of the color set back-projection algorithm, there have been
made some experiments over the medical images collection. For Method2 the
hexagon edge can be equal to 3, respective 4. For each query, the images from the
databases were inspected and relevance was assigned to them (1- relevant, 0 –
irrelevant) and the retrieval effectiveness using recall and precision was recorded.
Below, there are presented the results of one of the experiments.
Experiment:
In figure 5.3 there is the image for which there were detected the color regions
using Method2 with edge=3. Region6 was chosen as query region, which appears
as marked and emphasizes the sick area. The obtained results are presented in figure
5.4. It can be observed that the first five retrieved images are all relevant for
this query. The graphic of the retrieving efficiency in the case of the two presented
algorithms (Method1 and Method2 with edge =3) is shown in figure 5.5. The
graphics corresponding to the two methods are superposed, which means that the
results of this one region query are identical.
Fig. 5.3. The image with detected color regions using Method2 and edge=3; Region6 (representing
the sick area) marked for the content-based region query
The very good results obtained in the effectuated experiments indicate the fact
that each of the two implementations methods (Method1 and Method2) of the
color set back-projection algorithm can be used in the processing of the content–
based visual query. The experiments show that the results obtained with the
Method2 and edge=3 are closer in quality with those obtained with Method1.
The advantage of the second method (Method 2 with edge equal to 3) is given
by the fact that for detecting the color regions it is not necessary the pixel-by-pixel
image traversal, but only the pixels arranged in the vertices of a hexagon with