# Questions tagged [speech-recognition]

Speech recognition is the process of converting the spoken word to text, usually without regard to a particular speaker (which is more commonly referred to as "voice recognition").

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### Help in LBG Vector Quantization - Splitting Factor

I'm currently making a program for speech recognition. In the step of codebook generation using the LBG (Linde-Buzo-Gray) algorithm, I've read that the splitting factor $\varepsilon = 0.01$ (generally)...
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### Frame lookup using audio

I'm an animator trying to get a program that will use machine learning to automate the lip syncing process. The program I need made will have two files given to it: a seed, and an audio file. The seed ...
29 views

### Understanding MFCC

I am not from electrical or electronic background so my knowledge will be lacking. MFCC is represented by 39 values for each window frame. 12 values are the mel filter-bank and we get 13th value by ...
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### Speech recognition algorithm in GNU Octave to convert speech to text (and vice versa)

Recently, I am building an application in Octave and I saw some algorithms about speech recognition spread around the net, but most of them were implemented in Python, MATLAB, C++ and no one in Octave....
24 views

### Compare two spoken words with MFCC and DTW

Processing of the speech signal is done using Matlab. I want to use MFCC (Mel-frequency cepstral coefficients) is implemented using HTK and DTW (dynamic time warping v2.1) algorithms to make a speech ...
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### Removing background noise algorithm

What is the algorithm for removing background noise from an audio clip of human speech? Say I have a 10 second audio clip of somebody talking, and there is background noise of them tapping on their ...
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### MFCCs: magnitude spectrum vs power spectrum

As I know, the magnitude spectrum and power spectrum have the same information in this step before applying Mel-Filterbank, and the power spectrum may work slightly better in noise. However, I don't ...
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### Audio in Image,Graph or WaveForm Representation

Our task is to feed the audio data into the deep learning tensor flow model in the form of image representation(or graphical,waveform). Question is what is the best way of representing audio in image ...
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### Understanding liftering as the final step in MFCCs features extraction

In the book here, they apply liftering, as a final step of MFCCs features extraction, to isolate the system component by multiplying the whole cepstrum by a rectangular window centred on lower ...
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### MFCCs and mean normalization

I'm reading a blog about extracting MFCCs features for Machine Learning applications, but I didn't understand the following points about the mean normalization: To balance the spectrum and improve ...
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### filterbank: understand the different responses at the center frequency of each filter

I'm computing filterbank by applying 26 triangular filters on a Mel-scale to the power spectrum of an audio frame to extract frequency bands, and I found that some references use filterbank with equal ...
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### How to generate d-vector or MFCC from wav for speaker diarization and then voice print idenfication?

This task of voice print identification is way beyond my current knowledge. I googled heavily and have basic algorithm: given: conversation btw customer and tech support operator(debt collection in ...
37 views

### Difference between Cepstrum and Spectral Envelope

I have no background in Signal processing and i don't understand the difference between cepstrum and spectral envelope. IDFT of the log magnitude of the DFT of a signal is cepstrum then what is ...
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### Mixing signal with noise in frequency space (STFT)

I am working on a preprocessing function which is supposed to mix two audio signals clean and noise in the context of neural ...
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### python3: speech recognition - calculating features of a WAV file

I am supposed to do this as a school project, but I am kind of lost when it comes to signals and would appreciate your help. Also, English is not my first language, and I will be translating the ...
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### audio classification based only on first few seconds

I record audio notes on my recorder, and each belongs to a certain category ("work", "parenting", "miscellaneous", etc.). At the beginning of each recording, I say the name of the category, then stay ...
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### Problem getting DTW to work for speech recognition

I used my ipad to record the words "This. Is. A. Test. This. Is. A. Test.", then downloaded it to my computer as a .MOV file and used ffmpeg to extract audio as WAV. I then used the tuneR package to ...
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### Targets for Deep Neural Network in acoustic model for speech recognition

I'm trying to come up to speed on the use of deep neural networks for speech recognition and I'm confused about what exactly are the targets for the DNN. I understand that the DNN tries to predict a ...
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### Stack features in wakeword model

I'm not clear how is the input features are stacked in wakeword applications. Taking https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/43969.pdf as an example, the author ...
305 views

### Preprocess sound for voice recognition in Pocket Sphinx on Raspberry Pi 3

I want to improve my voice recognition system on a Raspberry Pi 3 running Pocket Spinx. It's pretty accurate (limited recognition vocabulary) but is terrible when other noise is around. Is there any ...
679 views

### Why is the Hamming and Hanning window the most widely used for speech spectograms?

When taking the Short-Time Fourier Transform of the speech signal, windowing is applied to taper away the signal frame at both ends and mitigate introduced artifact at expense of the maximum ...
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### Audio from multiple microphones mixed to mono and ASR

I am trying to do speech recognition on an audio file which has 1 channel (mono). My problem is that the channel is comprised of the signal of 3 microphones which have captured the audio at different ...
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### Are delta and double delta features needed when classifying with LSTM

I understand that the combination of MFCCs, deltas and double deltas is a good feature to be used with HMMs for keyword detection problems. HMMs are limited by Markov Property and this limitation is ...
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### What are i-vectors and x-vectors in the context of Speech Recognition?

I have read that i-vectors and x-vectors are widely used in speaker recognition tasks but I don't get the difference between them and how exactly they work. Can someone explain it starting from the ...
117 views

### Calculate the Standard Deviation of Fundamental Frequency (MFCC)

I'm implementing a gunshot detector following the article "Algorithm for Gunshot Detection Using Mel-Frequency Cepstrum Coefficients (MFCC)" (paywall). In the article, the authors uses 22 features ...
120 views

### Fast Vocal Tract Length Normalization(VTLN) implementation?

My team is building a speech recognition model. As far as I know, Vocal Tract Length Normalization (VTLN) is an effective warping method that may help improve the model performance by diminishing ...
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### Is there any way that we can perform speech recognition without using Fourier transforms?

I am trying to research about speech recognition and why everyone uses Fourier transforms in going about the topic. I know that we get information related to the frequency of each sound uttered which ...
202 views

### Split audio file into audio phrases

I have couple of audio recordings of length 5 -7 min. I also have corresponding text to each audio file. I am not subject matter expert on speech to text but I am vaguely aware that much smaller ...
123 views

### Cleaning telephone audio

I have telephone audio at 16kHz and I am trying to use it with a speech transcription engine that converts spoken letters to text. However, the engine has some difficulty transcribing certain letters ...
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### Services for phoneme recognition? [closed]

I wonder if anyone can point me to services or dev libraries that focus on or suit phoneme recognition? Target audience is children at learning to read stage. We have trialed IBM Watson (not good) ...
176 views

### why the MFCC is gender indenpend and used for isolated word recognition

I think female and male have total different MFCC feature for same word such as "one", but why the MFCC could be used for isolated word recognition which use the same HMM model for the same word ...
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### MFCC window size at different sampling rates

The general recommendation for window size when calculating MFCC seems to be 20-40 msec. This is most often recommended in a context of 16000 samples per second, so leading to a window containing 320-...
20 views

### Finding fundamental particles of sound In ASR systems? [closed]

Q1. Can we divide phonemes which are specific to a language into some more fundamental entities same across all languages ? Q2. Will this help us in achieving language independent acoustic modelling ...
560 views

### Slow implementation DTW for word recognition

I wrote little program for isolated word recognition using DTW algorithm. In folder with main program i have another folder "Data20dict", with 20 more folders in it, and each one is called by voice ...
605 views

### How to edit audios so that they have the same length

I have a dataset of audio files, which differ on their lengths by a couple of milliseconds. Some are little shorter than 1s and some are little longer than 1s. They all have the same sampling rate, ...
532 views

### MFCC Classification

I'm working on gender estimation from speech signal and I completed MFCC feature extraction. So now I'm trying to estimate gender from these features. But I have frames for an audio file and I ...
98 views

### Is there a known correlation between human voice (360Hz to 5kHz) and the frequencies above/below that?

Hello SignalProcessing! Given the important frequencies of a human voice (360Hz to 5kHz) to communicate and the frequencies above and below that make the voice sound way better. Imagine we are ...
666 views

### Does speaker recognition system need the same sample rate audio?

I'm a new man in speaker recognition project. I've train a model with some .wav files, its sample rate is 16000. I want to test this model with my record, but my record's sample rate is 8000 Doed it ...
34 views

### Is it possible to detect that sound source is playback of a recording?

I have been trying to find an article where it is described how real-time (or close to real-time) signal processing from a microphone is able to detect that an audio source is playback of a recording ...
307 views

### Remove a known wav file from recorded file

I looked at many similar questions but still cannot find an answer to my problem. I'm playing an audio file N, while recording a man talking (b). The problem is that the microphone gets the played ...
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### Keyword spotting - constant phoneme length

I wish to implement a keyword spotting algorithm (in speech), on the basis of what was published in this article (Apple's Machine Learning Journal). The article describes a neural-network-based ...
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### MFCC in Speech Recognition and ANN

I have a dataset with over 2000 examples of digits (0 to 9) recorded on wav files. I'm trying to process these files with MFCC so that later I could train an Artificial Neural Network (ANN). My ...
1k views

### Why is LPCC and LPC used in speech recognition

I am currently trying to understand why LPCC and LPC is being used in speech recognition and why? LPC as I understand is model similar to source filter model, modelling speech production, and LPC ...
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### Mel separated filter banks

I am currently a bit confused. I am currently trying to understand the MFCC extraction process, and don't understand how the Mel filter banks only provide a scalar output from each filter bank. What ...
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### Cepstrum calculus disambiguation

Learning the cepstrum analysis for speech recognition, I have met two different definitions of cepstrum (for discrete signals): $F^{-1}(ln|F(x[n])|)$ . That is, the cepstrum is the inverse Fourier ...
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### Speech recognition question

I am searching for a software that will translate speech to text but if it does not recognise a word, it will simply write a close resemblance to a word only misspelled, for example, if I say the word ...
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### RNN as posterior probability estimation in speech recognition with HTK

I'm new to speech recognition and deep learning and in a learning phase. I'm trying to follow this paper to learn how to use RNN as posterior probability estimation in an HTK environment. The paper ...