DNN Acoustic Model Training via Frame Segmentation
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Solution Overview
Problem
Conventional Deep Neural Network (DNN) training for acoustic modeling in speech recognition often leads to over-fitting due to reliance on irrelevant information from side frames, which affects the accuracy of speech recognition.
Innovation Solution
The method involves pre-training and fine-tuning the DNN, emphasizing connections between acoustic features in central frames and units of the bottom layer, while optionally applying regularization to side frames to reduce their influence, thereby improving speech recognition accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If acoustic features from side frames are included in the input layer, then the DNN can capture broader acoustic context, but the model is prone to over-fitting due to irrelevant information from side frames
Solution Approach 1:
The patent segments the acoustic context into central frames (relevant) and side frames (less relevant). The DNN input layer is structured to receive different frame types, and the training process learns to weigh them differently, effectively segmenting the influence of different acoustic contexts on the final recognition result.
Solution Approach 2:
The patent applies local quality by treating central frames and side frames differently in the training process. Central frames receive full attention during both pre-training and fine-tuning, while side frames have their connections regularized during fine-tuning. This creates different quality levels of feature utilization across different parts of the input data.
2Reliability
If regularization is applied to connections from side frames, then over-fitting is prevented, but the training process becomes more complex
Solution Approach 1:
The patent applies preliminary action by first performing pre-training on the entire DNN using all input frames (central and side) without regularization. This establishes a baseline model that captures general acoustic patterns. Only after this preliminary training is complete does the fine-tuning phase apply regularization selectively to side frame connections, preventing over-fitting at the appropriate stage.
Solution Approach 2:
The patent applies partial action by selectively regularizing only the connections from side frames during fine-tuning, while leaving the connections from central frames unregularized. This partial application of regularization targets specifically the problematic source of over-fitting (side frames) without unnecessarily constraining the beneficial central frame connections.
Data Source
AI summary
A method is provided for training a Deep Neural Network (DNN) for acoustic modeling in speech recognition. The method includes reading central frames and side frames as input frames from a memory. The side frames are preceding side frames preceding the central frames and/or succeeding side frames succeeding the central frames. The method further includes executing pre-training for only the central frames or both the central frames and the side frames and fine-tuning for the central frames and the side frames so as to emphasize connections between acoustic features in the central frames and units of the bottom layer in hidden layer of the DNN.


