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Gabor Wavelets

Similar to the system of Lades et al. [5], we apply a wavelet transform based on the Gabor kernel

 \begin{displaymath}\psi_{j}(\vec{x}) = \frac{k_{j}^{2}}{\sigma^{2}}
\end{displaymath} (1)


\end{displaymath} (2)

All the Gabor wavelets are created from this kernel by dilation and rotation. The 40 wavelets created from indices $\nu\in\{0,...,4\}$ (size) and $\mu\in\{0,...,7\}$ (orientation) are shown in figure 4. These wavelets are convolved with the image, and we keep the value of the center pixel. This provides us with a feature vector of 80 complex coefficients, but we only keep the amplitudes for classification.

Figure 4: The Gabor wavelets.

Erik Hjelmås