Figure 4. Clustering and classification of BSPM integrals.

a) Clustering of 57 patterns of BSPM integrals (30 from right and 27 from left atrium) using the K-means algorithm on the torso surface nodes where K is the number of pre-defined ectopy clusters (ECs). For each K, all the foci belonging to the same EC have the same color. b) For each K, left column shows the color and number of each EC resulting from the clustering step (for example blue-k2–0 refers to blue EC, equivalent to class 0, when k=2), while right column shows the classification results identifying the ectopic site that is not well classified with the color of the correct group, to which it really belongs. Reproduced from [⁶⁶].