FrostImageFilter.rst

This example illustrates the use of the :doxygen:`FrostImageFilter`. This filter belongs to the family of the edge-preserving smoothing filters which are usually used for speckle reduction in radar images.

This filter uses a negative exponential convolution kernel. The output of the filter for pixel p is:

\hat I_{s}=\sum_{p\in\eta_{p}} m_{p}I_{p}

m_{p}=\frac{KC_{s}^{2}\exp(-KC_{s}^{2}d_{s, p})}{\sum_{p\in\eta_{p}} KC_{s}^{2}\exp(-KC_{s}^{2}d_{s, p})}

d_{s, p}=\sqrt{(i-i_{p})^2+(j-j_{p})^2}

where:

• K: the decrease coefficient
• (i, j): the coordinates of the pixel inside the region defined by \eta_{s}
• (i_{p}, j_{p}): the coordinates of the pixels belonging to \eta_{p} \subset \eta_{s}
• C_{s}: the variation coefficient computed over \eta_{p}

Result of applying the FrostImageFilter to a SAR image.