Elbow detection using the Kneedle algorithm for t = 105 (left) and t = 205 (right) with different values of the sensitivity parameter. The elbow value has a huge influence on the quality of clustering. The curves on the right can be argued to have three elbows: one steep convex elbow, one soft convex elbow, and one concave elbow. We are interested in the steepest convex elbow, and therefore we choose a sensitivity = 1 in this paper.