Access and Retrieval from Image Databases Using Image Thumbnails

The emerging role of thumbnail images in the selection of images for display from large image databases and via network access requires that the characteristics of thumbnails be seriously studied. We introduce a measure of effective compression C eff (p) that is a function of the probability p that thumbnail access will be followed by the display of a full-scale image. For credible values of p, we deduce the need for the development of thumbnail-based image compression schemes, which efficiently and effectively use thumbnail data as part of the code for the full-scale image. We briefly discuss design features of thumbnail-based variants of the block-oriented coding schemes of vector quantization, fractal coding, and JPEG. 1. THUMBNAIL IMAGES Thumbnail images are now commonly used as WYSIWYG directory icons for the selection of images from directories and local databases. Notable systems for managing query of image databases, the QBIC system developed by Niblack and coworkers at IBM S..