Indexing of technical line drawing databases

Abstract

Image indexing, namely, the problem of retrieving content information from images in response to queries, is a key problem underlying the operations in image databases. In this paper we present a method of indexing for 3D object queries in a database of a class of images called technical line drawings. Indexing is achieved as a combination of query-specific region selection and object recognition. The selection phase isolates relevant images and the regions in these images that are likely to contain the queried object. This is done using text information in the query and a grouping mechanism that is guaranteed to isolate single-object containing regions for the class of technical line drawing images. The grouping mechanism is an adaptation of Waltz relaxation to an extended junction set derived by analyzing the physically plausible ways in which interpretation lines interact with object contours. Model-based object recognition then confirms the presence of the part at the selected location using geometrical description of the queried 3D object. Results are shown that indicate that query-specific selection is very effective for reducing the search during indexing while lowering the chance of false positives and negatives.