Localized Filters
Localized filters modify the value of each image pixel based on the value of pixels in its neighborhood. Localized filters can sometimes take the form of a convolution. Convolution filtering is a method for modifying the appearance of an image by convolving its pixel values with a specific kernel. When the convolution kernel is small it is more efficient to use the built-in operation MatrixConvolve. When the convolution kernel is relatively large it is more efficient to compute the convolution using the fast Fourier transform (FFT). A number of typical convolution kernels are implemented in the operation MatrixFilter which also contains a few localized (neighborhood) operators.
| avg | an nxn average filter. |
| findEdges | a 3x3 edge finding filter. |
| Gauss | a nxn Gaussian blur filter. |
| GradXX | 3x3 gradient filters with XX representing the two letters of the compass gradient direction. |
| median | a nxn median filter. |
| hybrid median | a 5x5 ranked median filter. |
| ranked median | user-defined ranked median filter. |
| sharpen | a 3x3 sharpening convolution filter. |
| thin | calculates image thining using neighborhood maps. |
Last updated: Thursday, January 13, 2005