Connectionist Temporal Classification Loss Function Research Articles

SilentInterpreter: Analysis of Lip Movement and Extracting Speech Using Deep Learning

Lip reading presents a captivating avenue for advancing speech recognition algorithms, leveraging visual cues from lip movements to recognise spoken words. This paper introduces a novel method employing deep neural networks to convert lip motions into textual representations. The methodology integrates convolutional neural networks for visual feature extraction, recurrent neural networks to capture temporal context, and the Connectionist Temporal Classification loss function for aligning lip features with phonemes. Additionally, dynamic learning rate scheduling and a unique callback mechanism for training visualization are incorporated into the process. Post-training on a sizeable dataset, the model demonstrates notable convergence, showcasing its ability to discern intricate temporal correlations. Comprehensive evaluations, combining quantitative metrics and qualitative assessments, validate the model's effectiveness. Visual inspections of lip reading capabilities and standard speech recognition criteria evaluation highlight its performance. The study delves into the impact of various model topologies and hyperparameters on performance, providing valuable insights for future research directions. This research contributes a deep learning framework for accurate and efficient speech recognition, expanding the landscape of lip reading technologies. The findings open paths for further refinement and deployment across diverse domains, including assistive technologies, audio-visual communication systems, and human-computer interaction. Keywords: lip reading, deep learning, convolutional neural networks, recurrent neural networks, CTC loss, speech recognition

Survey on Silentinterpreter : Analysis of Lip Movement and Extracting Speech using Deep Learning

Lip reading is a complex but interesting path for the growth of speech recognition algorithms. It is the ability of deciphering spoken words by evaluating visual cues from lip movements. In this study, we suggest a unique method for lip reading that converts lip motions into textual representations by using deep neural networks. Convolutional neural networks are used in the methodology to extract visual features, recurrent neural networks are used to simulate temporal context, and the Connectionist Temporal Classification loss function is used to align lip features with corresponding phonemes. The study starts with a thorough investigation of data loading methods, which include alignment extraction and video preparation. A well selected dataset with video clips and matching phonetic alignments is presented. We select relevant face regions, convert frames to grayscale, then standardize the resulting data so that it can be fed into a neural network. The neural network architecture is presented in depth, displaying a series of bidirectional LSTM layers for temporal context understanding after 3D convolutional layers for spatial feature extraction. Careful consideration of input shapes, layer combinations, and parameter selections forms the foundation of the model's design. To train the model, we align predicted phoneme sequences with ground truth alignments using the CTC loss. Dynamic learning rate scheduling and a unique callback mechanism for training visualization of predictions are integrated into the training process. After training on a sizable dataset, the model exhibits remarkable convergence and proves its capacity to understand intricate temporal correlations. Through the use of both quantitative and qualitative evaluations, the results are thoroughly assessed. We visually check the model's lip reading abilities and assess its performance using common speech recognition criteria. It is explored how different model topologies and hyperparameters affect performance, offering guidance for future research. The trained model is tested on external video samples to show off its practical application. Its accuracy and resilience in lip-reading spoken phrases are demonstrated. By providing a deep learning framework for precise and effective speech recognition, this research adds to the rapidly changing field of lip reading devices. The results offer opportunities for additional development and implementation in various fields, such as assistive technologies, audio-visual communication systems, and human-computer interaction.

A Real-Time ATC Safety Monitoring Framework Using a Deep Learning Approach

A deep learning-based safety monitoring framework for air traffic control (ATC) systems is proposed in this paper to reduce human errors and relieve the controllers’ workload by regulating the controlling procedure, eliminating communication misunderstanding, monitoring flight conformance, and detecting potential conflicts. The framework comprises automatic speech recognition (ASR), controlling intent inference (CII), and control safety monitoring (CSM) subsystems. The pipeline of the proposed framework can be described as follows: the ASR subsystem translates the pilot-controller voice communications (PCVCs) into texts, which are then converted to the predefined data structure by the CII subsystem. Three types of air traffic safety measures, including repetition check, flight conformance verification, and potential conflict detection, are finally validated by the CSM subsystem. An improved end-to-end ASR model with convolutional, bidirectional long short-term memory (BLSTM) and fully connected (FC) layers is trained using the connectionist temporal classification loss function. The BLSTM and FC combined CII model is designed to infer the controlling intent and slot filling. A language model is also trained in this subsystem to improve the overall performance of the framework. After converting the PCVCs to ATC data, the CSM subsystem checks the given safety monitoring tasks and sends warnings to the current system. The experimental results show that the proposed ASR model obtains a better performance than that of other approaches, and the tasks in the CII subsystem are fulfilled with a high classification precision. The CSM subsystem is also tested to confirm its safety monitoring function by playing back the data and several simulated instructions. To the best of our knowledge, this is pioneering work in the safety monitoring of flight control by recognizing the PCVCs with deep learning-based methods.

Focal CTC Loss for Chinese Optical Character Recognition on Unbalanced Datasets

In this paper, we propose a novel deep model for unbalanced distribution Character Recognition by employing focal loss based connectionist temporal classification (CTC) function. Previous works utilize Traditional CTC to compute prediction losses. However, some datasets may consist of extremely unbalanced samples, such as Chinese. In other words, both training and testing sets contain large amounts of low‐frequent samples. The low‐frequent samples have very limited influence on the model during training. To solve this issue, we modify the traditional CTC by fusing focal loss with it and thus make the model attend to the low‐frequent samples at training stage. In order to demonstrate the advantage of the proposed method, we conduct experiments on two types of datasets: synthetic and real image sequence datasets. The results on both datasets demonstrate that the proposed focal CTC loss function achieves desired performance on unbalanced datasets. Specifically, our method outperforms traditional CTC by 3 to 9 percentages in accuracy on average.

Cross-lingual adaptation of a CTC-based multilingual acoustic model

Multilingual models for Automatic Speech Recognition (ASR) are attractive as they have been shown to benefit from more training data, and better lend themselves to adaptation to under-resourced languages. However, initialisation from monolingual context-dependent models leads to an explosion of context-dependent states. Connectionist Temporal Classification (CTC) is a potential solution to this as it performs well with monophone labels.We investigate multilingual CTC training in the context of adaptation and regularisation techniques that have been shown to be beneficial in more conventional contexts. The multilingual model is trained to model a universal International Phonetic Alphabet (IPA)-based phone set using the CTC loss function. Learning Hidden Unit Contribution (LHUC) is investigated to perform language adaptive training. During cross-lingual adaptation, the idea of extending the multilingual output layer to new phonemes is introduced and investigated. In addition, dropout during multilingual training and cross-lingual adaptation is also studied and tested in order to mitigate the overfitting problem.Experiments show that the performance of the universal phoneme-based CTC system can be improved by applying dropout and LHUC and it is extensible to new phonemes during cross-lingual adaptation. Updating all acoustic model parameters shows consistent improvement on limited data. Applying dropout during adaptation can further improve the system and achieve competitive performance with Deep Neural Network / Hidden Markov Model (DNN/HMM) systems on limited data.

End-to-End Neural Optical Music Recognition of Monophonic Scores

Optical Music Recognition is a field of research that investigates how to computationally decode music notation from images. Despite the efforts made so far, there are hardly any complete solutions to the problem. In this work, we study the use of neural networks that work in an end-to-end manner. This is achieved by using a neural model that combines the capabilities of convolutional neural networks, which work on the input image, and recurrent neural networks, which deal with the sequential nature of the problem. Thanks to the use of the the so-called Connectionist Temporal Classification loss function, these models can be directly trained from input images accompanied by their corresponding transcripts into music symbol sequences. We also present the Printed Music Scores dataset, containing more than 80,000 monodic single-staff real scores in common western notation, that is used to train and evaluate the neural approach. In our experiments, it is demonstrated that this formulation can be carried out successfully. Additionally, we study several considerations about the codification of the output musical sequences, the convergence and scalability of the neural models, as well as the ability of this approach to locate symbols in the input score.