Library and Information Science

In processing photo materials special considerations should be given technically for obtaining higher efficiency of recall, precision and responce time. The retrieval of photo materials which requires the matching of image in mind against the visual cannot be done by the existing techniques of pattern recognition. Visual image cannot be indexed without extracting terms representing its, concepts. Since a photograph gives various kinds of impressions to people watching it, different terms tend to be assigned by different indexers to it.

This inconsistency results in increasing omission and noise factors when retrieving those photo materials. Therefore, an indexing scheme should be devised to overcome the inconsistency. To do this, we designed a special facet scheme and conducted the experiments using the scheme.

First, we experimented with sixty-five indexers assigning keywords to a set of sample photographs. The indexers did not have any limitations except being obliged to assign two keywords to each photograph. Keywords assigned were examined and used to form a facet scheme. The scheme consists of six, facets: Subject, Object, Place, Action and/or Condition, and Time.

Then, the second group of fifty indexers conducted the experiment using this facet scheme where they assigned keywords to each photograph.

The facet scheme was modified according to the results of the second experiment. The modifications are as follows: Title in place of Subject is independent of facet scheme, multiple Object are used as O1, O2, .... On, Place and Time are represented by P1 and P2, and T1 and T2 respectively, Content consisting of Action, Condition and Latent Factor is introduced.

We gave name of new scheme “OPTiC Patter” taken from the initial letter of Object, Place, Time, and Content.