Speaker Recognition

By Afshan Hina

Overview

• What is speaker recognition?• Voice Pattern • Categories of Speaker recognition.• Verification versus identification• Phases of speaker recognition• Technology used• Advantages and disadvantages• Conclusion• Commentary

Speaker Recognition

• Also referred as voiceprint recognition or voice recognition.• Identifies sound. • Such systems extract features from speech, model them

and use them to recognize the person from his/her voice.• Differs from speech recognition- where words are identified

and not speaker.• r eh k ao g n ay z s p iy ch

"recognize speech" • r eh k ay n ay s b iy ch”

"wreck a nice beach"

Voice patterns• uses the acoustic

features of speech that have been found to differ between individuals.

• These acoustic patterns reflect both anatomy and learned behavioral patterns

Voice patterns• But the data used in a voiceprint is a sound

spectrogram, not a wave form.• Spectrograms also use colors or shades of grey

to represent the acoustical qualities of sound.

Categories

• Field text• Text dependant• Text independent• Conversational.

Verification versus identification

• Speaker verification: If the speaker claims to be of a certain identity and the voice is used to verify this claim. Is usually used in applications which require secure access. Its a 1:1 match.

• Speaker identification: is the task of determining an unknown speaker's identity. It’s a 1:N match

Phases of speaker recognition

• Enrollment Phase: During enrollment the speaker's voice is recorded and typically a number of features are derived to form a voice print, template, or model.

• Test Phase: In the test phase (also called verification or identification phase) the speaker's voice is matched to the templates or models

Technologies used:

• frequency estimation• hidden Markov models• pattern matching algorithms• neural networks• matrix representation• decision trees

Advantages

• Remote authentication over legacy phone line.• Users do not have to remember passwords or

pass phrases.• Users do not have to go through separate

process of verification.

Disadvantages

• Misspoken or misread prompted phrases.• Extreme emotional states• Time varying microphone placement.• Poor or inconsistent room acoustics• Channel mismatch• Sickness• Aging.

Conclusion

• speaker verification is a pervasive low cost way of including a biometric check.

• does not require specialized equipment to use the system.

• It provides a very strong binding between the presented credential (voice) and the user.

Commentary

• Although speaker verification performance can be affected by various human and external factors, it does provide a powerful authentication solution.