Bio-medical Ontologies Maintenance and Change Management

104 L. Stanescu, D. Dan Burdescu, and M. Brezovan
In figure 3.8 there are presented some of images retrieved in the case of quantization
at 166 colors and using the histograms intersection. The first image is the
query image. The “r” symbol indicates that the image was established as relevant,
and “nr” like irrelevant.
(query) ( r )
( r ) ( r )
( r ) ( r )
( r ) ( r )
Fig. 3.8. Stomach and duodenum ulcers. The retrieved images using the histograms intersection
in the case of the quantization at 166 colors for the query image from the first position.
In our experiments, the best results were obtained, constantly, computing the
histogram intersection or the histogram quadratic distance in all three cases of
quantization. Also, the histogram Euclidian distance gave satisfying results. The
color space and the number of quantized colors do not influence very much the
queries results. As a result, the HSV color space quantized at 166 colors can be
considered the best solution (because the execution speed is higher).
The effectuated studies shown that none of the distances mentioned above produces
much better results than the others. In each case, relevant images for the
query were retrieved with one of the distances and the others did not retrieve
them. It could be observed that in most cases, all the results retrieved by computing
the three distances may be useful for not loosing relevant images for the query;
consequently, they complement one another. In conclusion, it can be executed a
parallel display of the images provided by the all three distances that have been
studied.