Abstract

This paper describes a post-evaluation analysis of the system developed by ViVoLAB research group for the IberSPEECH-RTVE 2020 Multimodal Diarization (MD) Challenge. This challenge focuses on the study of multimodal systems for the diarization of audiovisual files and the assignment of an identity to each segment where a person is detected. In this work, we implemented two different subsystems to address this task using the audio and the video from audiovisual files separately. To develop our subsystems, we used the state-of-the-art speaker and face verification embeddings extracted from publicly available deep neural networks (DNN). Different clustering techniques were also employed in combination with the tracking and identity assignment process. Furthermore, we included a novel back-end approach in the face verification subsystem to train an enrollment model for each identity, which we have previously shown to improve the results compared to the average of the enrollment data. Using this approach, we trained a learnable vector to represent each enrollment character. The loss function employed to train this vector was an approximated version of the detection cost function (aDCF) which is inspired by the DCF widely used metric to measure performance in verification tasks. In this paper, we also focused on exploring and analyzing the effect of training this vector with several configurations of this objective loss function. This analysis allows us to assess the impact of the configuration parameters of the loss in the amount and type of errors produced by the system.

Highlights

  • A multimodal biometric verification field consists of the identification of persons by means of more than one biometric characteristics, as the use of two modalities makes the process more robust to potential problems

  • Different alternatives have been presented in the literature to design loss functions focused on the final evaluation metrics to train the deep neural networks (DNN) systems such as the approximated area under the ROC curve [16,17], the partial and multiclass AUC loss [18,19,20], and the approximated detection cost function [14] which was used for this work

  • We compared the use of a cosine similarity metric directly on the embeddings extracted from the pretrained model (AverageEmbedding) to obtain the closest identity in each instance with the training face enrollment models approach (EnrollmentModels) for the identity assignment process

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Summary

Introduction

A multimodal biometric verification field consists of the identification of persons by means of more than one biometric characteristics, as the use of two modalities makes the process more robust to potential problems. Face and voice characteristics have been two of the preferred biometric data due to the ease of obtaining audiovisual resources to carry out the systems that perform this process When this identification process is applied throughout a video file, and this information is kept over time, this kind of task is known as multimodal diarization combined with identity assignment. In recent years, this field has been widely investigated due to its great interest, motivated by the fact that human perception uses acoustic information and visual information to reduce speech uncertainty.

RTVE 2020 Challenge
Face Enrollment Models
Training Process of Enrollment Models
Face Subsystem
Frame Extraction
Face Detection
Change Shot Detection
Embedding Extraction
Training Face Enrollment Models
Clustering
Tracking and Identity Assignment Scoring
Speaker Subsystem
Front-End and Speech Activity Detection
Speaker Change Point Detection
Identity Assignment Scoring
Performance Metrics
Results
Analysis of Training Enrollment Models for Face Subsystem
Summary of Face and Speaker Results
Conclusions
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