30-07-2013, 03:58 PM
VOICE RECOGNITION SYSTEM
[attachment=56838]
FUNCTION
Create a dictionary of 3-5 words.
Compare a test word spoken by the user with the words stored in the dictionary and display the word if a match is found.
STRUCTURE
The microphone analog circuit goes to the ADC of the MCU. The digitized sampling of the word is passed through the digital Chebyshev filters (flash programmed onto the MCU). Once the analysis is done, a fingerprint of the word is created and stored in the memory.
While recording the stored fingerprints form the dictionary, against which the fingerprint of the test word is compared using methods such as Euclidean distance and correlation.
At the time of testing, once the comparisons between the test word and the dictionary are made, the LCD which is connected to the MCU displays the word spoken if it has a match in the dictionary.
The software tradeoff in this project is between the number of filters we can implement and the maximum number of cycles we have to adhere to. The more filters there are, the more accurate the speech recognition will be.
ALGORITHMS & TECHNIQUES
What we needed to know in this project is how to calculate the frequency to sample speech based on the Nyquist Rate Theorem. According to this theorem, the sampling rate must be atleast twice the maximum frequency of the sample input.
We had to learn about Chebyshev filters to determine the cutoff frequencies to build the digital filters for human voice.
As for the analysis part of the speech, we needed to know how to calculate euclidean distance and correlation.
[attachment=56838]
FUNCTION
Create a dictionary of 3-5 words.
Compare a test word spoken by the user with the words stored in the dictionary and display the word if a match is found.
STRUCTURE
The microphone analog circuit goes to the ADC of the MCU. The digitized sampling of the word is passed through the digital Chebyshev filters (flash programmed onto the MCU). Once the analysis is done, a fingerprint of the word is created and stored in the memory.
While recording the stored fingerprints form the dictionary, against which the fingerprint of the test word is compared using methods such as Euclidean distance and correlation.
At the time of testing, once the comparisons between the test word and the dictionary are made, the LCD which is connected to the MCU displays the word spoken if it has a match in the dictionary.
The software tradeoff in this project is between the number of filters we can implement and the maximum number of cycles we have to adhere to. The more filters there are, the more accurate the speech recognition will be.
ALGORITHMS & TECHNIQUES
What we needed to know in this project is how to calculate the frequency to sample speech based on the Nyquist Rate Theorem. According to this theorem, the sampling rate must be atleast twice the maximum frequency of the sample input.
We had to learn about Chebyshev filters to determine the cutoff frequencies to build the digital filters for human voice.
As for the analysis part of the speech, we needed to know how to calculate euclidean distance and correlation.