“…Nevertheless, using accuracy as the evaluation metric for learning does not always produce the most useful classification system in the real world. In fact, many real-world applications [12,13,14,15,16], including vision related, demand varying costs for different types of misclassification errors. For example, different costs are useful for building a realistic face recognition system [15,17,18,19], in which a government staff being misrecognized as an impostor causes only a slight inconvenience; however, an imposer misrecognized as a staff can result in serious damage.…”