TY - JOUR
T1 - Speech enhancement for secure communication using coupled spectral subtraction and wiener filter
AU - Pardede, Hilman
AU - Ramli, Kalamullah
AU - Suryanto, Yohan
AU - Hayati, Nur
AU - Presekal, Alfan
N1 - Funding Information:
Funding: This work was supported by Lembaga Pengelola Dana Pendidikan (LPDP) RISPRO from the Ministry of Finance of the Republic of Indonesia.
Funding Information:
This work was supported by Lembaga Pengelola Dana Pendidikan (LPDP) RISPRO from the Ministry of Finance of the Republic of Indonesia.
Publisher Copyright:
© 2019 Intellect Ltd Article. English language.
PY - 2019/8/1
Y1 - 2019/8/1
N2 - The encryption process for secure voice communication may degrade the speech quality when it is applied to the speech signals before encoding them through a conventional communication system such as GSM or radio trunking. This is because the encryption process usually includes a randomization of the speech signals, and hence, when the speech is decrypted, it may perceptibly be distorted, so satisfactory speech quality for communication is not achieved. To deal with this, we could apply a speech enhancement method to improve the quality of decrypted speech. However, many speech enhancement methods work by assuming noise is present all the time, so the voice activity detector (VAD) is applied to detect the non-speech period to update the noise estimate. Unfortunately, this assumption is not valid for the decrypted speech. Since the encryption process is applied only when speech is detected, distortions from the secure communication system are characteristically different. They exist when speech is present. Therefore, a noise estimator that is able to update noise even when speech is present is needed. However, most noise estimator techniques only adapt to slow changes of noise to avoid over-estimation of noise, making them unsuitable for this task. In this paper, we propose a speech enhancement technique to improve the quality of speech from secure communication. We use a combination of theWiener filter and spectral subtraction for the noise estimator, so our method is better at tracking fast changes of noise without over-estimating them. Our experimental results on various communication channels indicate that our method is better than other popular noise estimators and speech enhancement methods.
AB - The encryption process for secure voice communication may degrade the speech quality when it is applied to the speech signals before encoding them through a conventional communication system such as GSM or radio trunking. This is because the encryption process usually includes a randomization of the speech signals, and hence, when the speech is decrypted, it may perceptibly be distorted, so satisfactory speech quality for communication is not achieved. To deal with this, we could apply a speech enhancement method to improve the quality of decrypted speech. However, many speech enhancement methods work by assuming noise is present all the time, so the voice activity detector (VAD) is applied to detect the non-speech period to update the noise estimate. Unfortunately, this assumption is not valid for the decrypted speech. Since the encryption process is applied only when speech is detected, distortions from the secure communication system are characteristically different. They exist when speech is present. Therefore, a noise estimator that is able to update noise even when speech is present is needed. However, most noise estimator techniques only adapt to slow changes of noise to avoid over-estimation of noise, making them unsuitable for this task. In this paper, we propose a speech enhancement technique to improve the quality of speech from secure communication. We use a combination of theWiener filter and spectral subtraction for the noise estimator, so our method is better at tracking fast changes of noise without over-estimating them. Our experimental results on various communication channels indicate that our method is better than other popular noise estimators and speech enhancement methods.
KW - Noise estimation
KW - Secure voice communication
KW - Spectral subtraction
KW - Speech enhancement
KW - Wiener filter
UR - http://www.scopus.com/inward/record.url?scp=85071852677&partnerID=8YFLogxK
U2 - 10.3390/electronics8080897
DO - 10.3390/electronics8080897
M3 - Article
AN - SCOPUS:85071852677
SN - 2079-9292
VL - 8
JO - Electronics (Switzerland)
JF - Electronics (Switzerland)
IS - 8
M1 - 897
ER -