SOM Structure

Posted: January 28, 2009 at 2:27 am

Here is a U-Matrix representation of the memory map resulting from the Piksel installation:dm1-umatrix.png

The red Xs are units that were never associated with images. Note that due to a bug the histograms were truncated to 100 elements while being stored. This U-Matrix then only shows the similarity of the first 100 elements of the R channel histogram. A U-Matrix is normally calculated by the mean of the sum of differences between each unit and its neighbours. In this case the measure of similarity is based on the sum of the differences divided by the number of neighbours. The large amount of dark units means that this SOM was highly folded. Compare this to the U-Matrix and memory field below: