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This node works by combining neighboring pixels together in a user defined way. How these pixels are combined is determined by what values you put in the "kernel." This kernel is made up of 9 numbers that you can specify, and are arranged in a circle. The number in the center of the circle represents the pixel in question, while the numbers around the edges represent neighboring pixels.
Following is an example of a very simple kernel:
For each pixel, the "1" in the middle means that 100% of the original pixel will be taken, while 0% of the neighboring pixels will be taken. In other words, this kernel will leave the original image unchanged.
Following is a more interesting example:
This will cause the nearby values to bleed into each other, in other words, a blur. Each resulting pixel will be comprised of 12% of the corresponding source pixel, plus 11% of each of the source pixel's neighbors (totaling 100% so that original brightness is maintained).
A regular blur causes colors to bleed in all directions, while a motion blur causes colors to bleed in only one direction. This can be set up using a kernel such as the following:
In this case each resulting pixel will be composed of 34% of the corresponding source pixel, plus 33% the pixel to the left, plus 33% the pixel to the right.
Note that the matrix effects of most image processing packages arrange the kernel values in a rectangular fashion to facilitate specifying the specific nearby pixels to be weighted. However, since Genetica textures are resolution-independent, striving to have kernel values line up with specific pixels is meaningless. Therefore, instead of the traditional square kernel, the Matrix node's nine kernel values are arranged in a circle, allowing for more natural effects.
The node's single input provides the image to be processed.
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