Essentials of Pattern Recognition An Accessible Approach

With the full system introduced in Chapter 3, now we are ready to discuss how to evaluate the performance of a pattern recognition system: a task that seems easy at first glance but is in fact quite complex. We introduce core concepts such as error and accuracy rates, under- and overfitting, and parameters and hyperparameters. We pay special attention to imbalanced problems. Finally, we present a brief introduction on how confident we can be of the evaluation outcomes. We establish the fact that errors are inevitable in most pattern recognition systems, and also introduce a decomposition of errors into different terms.