After you catalog images, you can query one or more of the images by content. When you query an image by content, you identify input for the query and a target set of cataloged images. You can specify the input in a query string (see Specifying a query string) or in a query object (see Using a query object).
If you use a query string, you can submit the query from the DB2 command line or from within a program. If you use a query object, you submit the query from within a program, by referencing its handle.
The Image Extender compares the feature values that are specified in the query to those of the target images, and computes a score for each image. The score indicates how similar the feature values of the target image are to feature value that is specified in the query.
You can retrieve images whose feature values are most similar to the query. You can also query a single cataloged image and get its score, or get scores for all the cataloged images in a table column.