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    Saturday, October 08, 2005

    Speech Recognition: End-Point Detection

    The end point detection technique is applied to extract the region of interest from the raw speech signal. In other words, it removes the silent region from speech signals. The basic technique of end point detection is to find the energy level of a signal. Signal energy level is calculated in frames, where each frame consists of N samples. The frames are usually overlapped with the adjacent frames to produce a smooth energy line. Fig 1 shows the energy plot of “One”.

    Fig 1: (a) Amplitude vs time plot of “One” (b) energy level of the signal

    Accurate end point detection is important to reduce processing load and increase the accuracy of a speech recognition system. Basically there are two famous endpoint detection algorithms. First algorithm uses signal features based on energy levels and second algorithm uses signal features based on the rate of zero crossings. The combination of both gives good result, but nevertheless increases the complexity of the program and also the processing time.

    Fig 2 shows the signal of “one” sampled at 8000Hz for 10650 samples or 1.33 seconds. Before the speech begins, the waveform started as silence for about 5000 samples. After the utterance, the signal remains in silence state again for about 2000 samples. Throwing the unwanted silence region, the processing time can be improved to 3650/10650 * 100 = 34.3% by assuming all the frames in the region of interest have been processed. The energy level of the signal is inspected and a threshold value is determined from the energy plot. Fig 3 shows the cropped signal, where the silence region has been eliminated, and the remaining region of interest are used for further processing.

    Fig 2: (a) Original signal, (b) End-point detection by using the energy level of the speech signal

    Fig 3: (a) Detected end point, (b) Cropped signal/region of interest


    Blogger Esau said...


    I found your blog because I was looking for some information about algorithms to detect endpoints using energy. I would like to know if you have more information about this or if you can tell me where can I found it.


    2:14 AM  
    Blogger Esau said...


    it's me again I forgot to leave you my e-mail address: esaucastilloc@gmail.com!!

    Thanks again!

    2:15 AM  
    Blogger Ramkumar NJ said...

    Hi - Thanks for your info on end-point recognisition. Can you please let me know more details on end-point detection. I'm doing a project on VR for my engineering and your inputs will be really helpful.

    Thanks again,

    10:40 PM  
    Blogger 9i9i said...

    i want a matlab code for end point detection by using energy??

    thanks alot

    11:08 PM  
    Blogger 9i9i said...

    do you use neural network toolbox in matlab??

    11:09 PM  
    Blogger supermon said...

    hi, i want Speech Recognition: End-Point Detection code plese sent to super_mon21@hotmail.com

    4:20 AM  
    Blogger sri said...

    hi..,i want matlab code for end point detection and the crooped signal.....sent to email id:srividyajv20@gmail.com

    10:30 PM  
    Blogger E-roL said...

    may i know more detail about end-point detection.And i want matlab code for end point detection and the crooped signal.....kindly please sent to email id: kids.hasrul@gmail.com

    9:51 PM  
    Blogger marina said...

    hello,i want the matlab code for end point detection pls sent it to email

    7:55 AM  
    Blogger snap aoe said...

    Could u pls help me with my project by providing details on start-point and end-point detection ....!!!!.....

    my mail id is snapxaoe@gmail.com

    your help is appreciated.....

    12:29 PM  
    Blogger ehsan said...

    Hi dear,
    Can you send me the end-point detection matlab code please?

    2:21 AM  
    Blogger Sunrise said...


    Can you send me the start-point and end-point detection matlab code. It is very useful for my project. I greatly appreciate your help.
    email: an_tth@yahoo.com

    7:58 AM  
    Blogger Vanaja M said...

    This comment has been removed by the author.

    10:20 AM  
    Blogger Vanaja M said...

    hi..,i want matlab code for end point detection and the crooped signal.....sent to email id:vanajageni.m@gmail.com

    10:21 AM  
    Blogger Mintu Sanong said...

    How to plot a graph in matlab showing the speech with endpoint

    12:35 PM  
    Blogger Shivangi Chauhan said...

    I need Matlab code for speech recognition for my project it would be of great help if you could help me with this.
    email id: shivangic7@gmail.com

    3:00 AM  

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