A kernel is a (usually) smallish matrix of numbers that is used in image convolutions. Differently sized kernels containing different patterns of numbers give rise to different results under convolution. For instance, Figure 1 shows a 3×3 kernel that implements a mean filter.
Figure 1 Convolution kernel for a mean filter with 3×3 neighborhood.
The word `kernel' is also commonly used as a synonym for `structuring element', which is a similar object used in mathematical morphology. A structuring element differs from a kernel in that it also has a specified origin. This sense of the word `kernel' is not used in HIPR.
©2003 R. Fisher, S. Perkins,
A. Walker and E. Wolfart.