From Hard to Soft Biometrics Through DNN Transfer Learning

摘要

In this work we thoroughly study the well-known face verification Resnet model in dlib's library to uncover inner features related to soft biometrics attributes like gender, race and age. The study makes use of the t-SNE technique to understand the evolution of clustering through the pretrained network layers and reveals an interesting property of t-SNE to spot separability of clusters in the original space. The performance of simple classifiers for the secondary soft-biometrics tasks through the network reinforce the findings about t-SNE. This study is extensible to any model that maps the input classes into an embedded low-dimensional space that learned to cluster them in task-meaningful sets. We conclude that a state of the art face verification model can be easily leveraged to state of the art soft biometrics model without resorting to fine-tuning convolutional weights, which also allows reducing the model size and inference time.