Fast image copy detection approach based on local fingerprint defined visual words

Abstract

Recently the methods based on bag-of-visual words have become very popular in near-duplicate retrieval and content identification. However, obtaining the visual vocabulary by quantization is very time-consuming and unscalable to large databases. In this paper, we propose a fast copy detection method which uses local image fingerprints to define visual words. To construct the fingerprint, a 32-bit vector is extracted from the local description and then converted into a number which is used to define the visual word. Then, a histogram intersection is employed to measure the similarity between two images. Since the fingerprint building is of low-complexity, this method is very efficient and scalable to very large databases. Furthermore, the fingerprint-defined visual words are more discriminative and precise than the clustering-defined visual words because the vocabulary size could be large enough while maintaining high efficiency. Visual words with strong discriminability can distinguish copies from similar objects, which can reduce the number of false positives and improve the precision and efficiency. The evaluation shows that our approach significantly outperforms state-of-the-art methods.