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# System prepended metadata

title: Speech Processing

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# Speech Processing

[toc]

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## 1. General information and organization issues
:::info
- Voice-based human-machine communication via HMI - Human Machine Interface
    ![image](https://hackmd.io/_uploads/Bk9kuCQ2T.png)
- Dialogue systems like chatbox
    ![image](https://hackmd.io/_uploads/BJfYKCm3T.png)
    - the middle part is called Natural Language Processing (NLP)
    - TTS: Text-to-Speech
    - ASR: Automatic Speech Recognition
- speech transcription from acoustic to text form
    ![image](https://hackmd.io/_uploads/S1jm6CX3T.png)
    - replacement of keyboard by voice
    - automated transcription of audio records/streams
- speaker recognition
    - system of biometrics identification for autorization purposes, forensic applications
- human articulatory system
    ![image](https://hackmd.io/_uploads/r1n2JyE3a.png)
    - speech production model
        ![image](https://hackmd.io/_uploads/rJZ7GyEn6.png)
- samples of different parts of speech signal
    ![image](https://hackmd.io/_uploads/Hk3RV1436.png)
    - plosive sound is hard to deal with because of short duration
- general description of speech signal
    - acoustic level: purely analyze waveform and signal itself without considering content
    - phonetic level: information content, try to separate it into subwords
- signal sampling and quantization, Pulse Code Modulation(PCM)
    ![image](https://hackmd.io/_uploads/ByWfOJVna.png)
- speech sampling
    ![image](https://hackmd.io/_uploads/BkTbFyVn6.png)
    - linear quantization of speech signal
        ![image](https://hackmd.io/_uploads/SJsYj1N2T.png)
- freq. perception
    ![image](https://hackmd.io/_uploads/By-Xn1436.png)
    - itensity
        ![image](https://hackmd.io/_uploads/S1TZay4n6.png)
    - loudness
        ![image](https://hackmd.io/_uploads/SJSy0kVn6.png)
        > freq. 200 to 5000, we have the highest sensitivity for the sounds
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## 2. Basic time-domain and spectral characteristics of speech signal
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- Most of them are mathematical eq., check slide.
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