Milos Zelezný

LipsID Using 3D Convolutional Neural Networks

This paper presents a proposition for a method inspired by iVectors for improvement of visual speech recognition in the similar way iVectors are used to improve the recognition rate of audio speech recognition. A neural network for feature extraction is presented with training parameters and evaluation. The network is trained as a classifier for a closed set of 64 speakers from the UWB-HSCAVC dataset and then the last softmax fully connected layer is removed to gain a feature vector of size 256. The network is provided with sequences of 15 frames and outputs the softmax classification to 64 classes. The training data consists of approximately 20000 sequences of grayscale images from the first 50 sentences that are common to every speaker. The network is then evaluated on the 60000 sequences created from 150 sentences from each speaker. The testing sentences are different for each speaker.

Designing Advanced Geometric Features for Automatic Russian Visual Speech Recognition

The use of video information plays an increasingly important role for automatic speech recognition. Nowadays, audio-only based systems have reached a certain accuracy threshold and many researchers see a solution to the problem in the use of visual modality to obtain better results. Despite the fact that audio modality of speech is much more representative than video, their proper fusion can improve both quality and robustness of the entire recognition system that was proved in practice by many researches. However, no agreement between researchers on the optimal set of visual features was reached. In this paper, we investigate this issue in more detail and propose advanced geometry-based visual features for automatic Russian lip-reading system. The experiments were conducted using collected HAVRUS audio-visual speech database. The average viseme recognition accuracy of our system trained on the entire corpus is 40.62%. We also tested the main state-of-the-art methods for visual speech recognition, applying them to continuous Russian speech with high-speed recordings (200 frames per seconds).