Contribution of P
to the overall accuracy of the system. This figure depicts the contribution of the false rejection rate (P
FR) and the false classification rate (P
FC) to the overall performance of the proposed system when automatically detected facial features were used for alignment and estimation of other locations for local feature extraction. (A) Curves for the ChimpZoo dataset. (B) Results for the ChimpTaï dataset. The black solid line denotes the line of equal error. The blue area represents the influence of the false rejections, while the red area shows the contribution of the false classifications. For the ChimpZoo dataset, the error rate of the system at the point of equal error is mainly caused by false rejection of genuine individuals, and only 3.52% is due to false classifications. For the ChimpTaï dataset, however, 13.52% of the overall error rate is caused by false rejections, while 17.72% are caused by false classifications.