Analysis of BUT-PT Submission for NIST LRE 2017

In this paper, we summarize our efforts in the NIST Language Recognition Evaluations (LRE) 2017 which resulted in systems providing very competitive and state-of-the-art performance. We provide both the descriptions and the analysis of the systems that we included in our submission. We explain our partitioning of the datasets that we were provided by NIST for training and development, and we follow by describing the features, DNN models and classifiers that were used to produce the final systems. After covering the architecture of our submission, we concentrate on post-evaluation analysis. We compare different DNN Bottle-Neck features, i-vector systems of different sizes and architectures, different classifiers and we present experimental results with data augmentation and with improved architecture of the system based on DNN embeddings. We present the performance of the systems in the Fixed condition (where participants are required to use only predefined data sets) and in addition to official NIST LRE17 evaluation set, we also provide results on our internal development set which can serve as a baseline for other researchers, since all training data are fixed and provided by NIST.