Encyclopedia of Biometrics

2009 Edition
| Editors: Stan Z. Li, Anil Jain

Fusion, Wavelet-Based

Reference work entry
DOI: https://doi.org/10.1007/978-0-387-73003-5_564
Wavelet-based fusion has been widely used in literature. The wavelet transform is a data analysis tool that provides a multi-resolution decomposition of an image. Wavelet-based pixel-level data fusion is used on two or more sets of probe images. Given two registered images I 1 and I 2 of the same object from two sets of probe images (two different spectral bands in this case), a two-dimensional discrete wavelet decomposition is performed on I 1 and I 2 to obtain the wavelet approximation coefficients ( a 1, a 2) and detail coefficients ( d 1, d 2). The wavelet approximation and detail coefficients of the fused image, a f and d f, are then calculated as follows:
$$\eqalign{a_{\rm{f}} & = W_{a_1} \times {a_1} + W_{a_2} \times {a_2}\, {{\rm{and}}} \cr d_{\rm{f}} & = W_{d_1} \times {d_1} +W_{d_2} \times {d_2} ,}$$
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© Springer Science+Business Media, LLC 2009