The HiRDB Image Search Plug-in can extract image features from the colors and shapes of image data and register them into the HiRDB database. PBM is the only data type that the HiRDB Image Search Plug-in can handle.

When the digital contents input/output utility provided by Image Database Access is used, image data is first converted to the PBM format before being transferred to the HiRDB Image Search Plug-in, and therefore image features can be extracted from image data in other formats.

Image Database Access (CORBA object) is used to compare image features that have been registered in the database with the image features of the image to be retrieved and to determine their similarity.

The index creation plug-in for image searches can be used to create an index for a column that stores image features (ImageFeature-type column). When such an index has been created, images can be retrieved at high speed when image data is specified as the retrieval condition.