IME: an image management environment with content-based access

The article describes an experimental visual environment to handle digital images by contents. A suitable spatial index is used to organize the images in a spatial access structure for efficient storage and retrieval. An image is indexed according to both the spatial arrangement of its objects and the morphological and geometrical measures of these objects. Therefore, in the database population phase a user identifies the objects that characterize the visual content of each image by a user-friendly interface. In order to let the system retrieve images based on the presence of given patterns, it is necessary to define similarity matching criteria between a query and an image. To efficiently perform such a match, each image is stored together with a collection of metadata that are a very compact representation of the visual contents of the image. These metadata form the index of the image. The system implements a Spatial Access Method based on k-d-trees to achieve a significant speedup over sequential search. We prove the effectiveness and the efficiency of the system by performing standard tests on a database containing a large number of medical images, namely lung CT scans. (C) 1999 Elsevier Science B.V. All rights reserved.