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Detail of Publication

Text Language English
Authors Tomohiro Nakai, Koichi Kise, Masakazu Iwamura
Title Use of Affine Invariants in Locally Likely Arrangement Hashing for Camera-Based Document Image Retrieval
Journal Lecture Notes in Computer Science (7th International Workshop DAS2006)
Vol. 3872
Pages pp.541-552
Reviewed or not Reviewed
Month & Year February 2006
Abstract Camera-based document image retrieval is a task of searching document images from the database based on query images captured using digital cameras. For this task, it is required to solve the problem of “perspective distortion”of images, as well as to establish a way of matching document images efficiently. To solve these problems we have proposed a method called Locally Likely Arrangement Hashing (LLAH) which is characterized by both the use of a perspective invariant to cope with the distortion and the efficiency: LLAH only requires O(N) time where N is the number of feature points that describe the query image. In this paper, we introduce into LLAH an affine invariant instead of the perspective invariant so as to improve its adjustability. Experimental results show that the use of the affine invariant enables us to improve either the accuracy from 96.2% to 97.8%, or the retrieval time from 112 msec./query to 75 msec./query by selecting parameters of processing.
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