What is Automatic Speech Recognition?

The ability of computers to detect human speech and convert it into text is the goal of Automated Speech Recognition (ASR). Several different kinds of software make use of automated speech recognition systems, including personal digital assistants like Siri and Alexa, mobile voice search, and automated transcription services.

How Automatic Speech Recognition Works?

ASR essentially works by translating speech into text. Typically, ASR systems have three primary parts: acoustic modeling, language modeling, and decoding.

  • Acoustic Modeling– is a part of AI automatic speech recognition that uses analysis of the audio input to determine regularities in human speech. Machine learning algorithms are used to learn the acoustic properties of various speech sounds and then to map those sounds to particular symbols or words.
  • Language Modeling– Predicting the probability of a word sequence based on the surrounding speech context is the goal of the Language Modeling subsystem. A language model is used to determine the most likely string of words that would best describe the audio input.
  • Decoding– The outputs of the acoustic and linguistic models are combined in the decoding phase to form the final transcription. The decoding procedure is based on the language model’s probabilities, which are used to find the best possible sequence of words that matches the audio input.

Automatic Speech Recognition Applications

  • Virtual Assistants– ASR technology is at the heart of virtual assistants like Google Assistant, Amazon’s Alexa, and Apple’s Siri.
  • Voice Search– ASR technology is utilized in mobile devices and online search engines to enable users to do searches by speaking keywords or phrases.
  • Transcription Services– that rely on ASR transcribe speeches, meetings, and interviews, among other audio and video events, into text.
  • Speech To Text– applications are closed captioning for movies and TV programs and real-time translation services. ASR technology is utilized to create these applications.

Strategies for Improving Automated Speech Recognition

There are various obstacles that must be conquered before ASR systems may be made more accurate and reliable, despite technological advancements in the field.

  • Vocabulary Size– There is a possibility that ASR systems won’t be able to detect uncommon or odd words since they weren’t included in the training data due to their relatively small vocabulary size. Increasing the ASR model’s vocabulary coverage is one approach to overcoming this difficulty.
  • Speaker Diarization– Automatic Speech Recognition systems may have trouble telling numerous voices apart during a discussion. The quality of the ASR transcription may be enhanced by using speaker diarization algorithms to determine who is speaking during each audio segment.
  • Imbalanced Data– ASR systems may have trouble with recognizing speech from underrepresented groups such as non-native speakers and those with speech problems. Data augmentation and active learning are two methods that may be used to increase the variety of the training data and therefore help solve this problem.
  • Context– Speech recognition systems that rely on automatic voice recognition (ASR) technology may make mistakes in transcribing if they are unable to understand the context and purpose of the speaker. Other information, such as visual context or user history, might be included in the ASR model as a means of overcoming this difficulty.

Automatic Speech Recognition Models

There are two primary varieties of Automatic Speech Recognition models: the more common “conventional” models, and the more recent “end-to-end” models.

End-to-end ASR Models

By contrast, end-to-end ASR models include all three parts of standalone ASR models into a single artificial neural network. Without resorting to less-direct representations like phonetic units or language models, these models are trained to directly translate audio inputs to text.

  • CNN– To transcribe an audio stream, a Recurrent Neural Network (RNN) is fed features extracted from the data using a Convolutional Neural Network (CNN).
  • RNN– Modeling the temporal relationships in voice signals using RNNs allows for the generation of a string of characters that accurately represents the input audio.
  • Encoder– Models known as encoder-decoders employ a pair of neural networks, one to encode audio impulses and another to convert them to text.

In general, the ASR model that is used is determined by the task at hand and the resources at the user’s disposal. End-to-end models may be more appropriate for situations where huge volumes of data are accessible or where flexibility is vital, whereas traditional models may be better suited to low-resource environments or applications with rigorous accuracy requirements.