Sensor misalignment with injected independent noise. Additive white noise progressively degraded sensor alignment for a variety of training set sizes. (a) Point-to-point error increases with the percentage of error. Increasing the training set size from 3 to 16 samples (300-1600 ms) greatly reduced to slope of increase. However, further increases had minor effect, e.g. results for 1600 and 3200 samples overlap. (b) Correlation revealed a similar trend (3 sample results removed here to highlight the differences in the other training set sizes). Regardless of training set size, the testing sets were the same separate segment (1200 samples).