1. Communications & Multimedia Signal Processing Analysis of Effects of Train/Car noise in Formant Track Estimation Qin Yan Department of Electronic and Computer Engineering Brunel University 28 January, 2004

2. Communications & Multimedia Signal Processing Content Aim of current work Variation in formant SNR Effect of train/car noise on formant frequency estimation Effect of train/Car noise on formant tracking Future work plan

3. Communications & Multimedia Signal Processing Aim of Current Work Formant track can be employed for noise reduction. To obtain the reliable formant tracks from noisy speech, it is necessary to analyse the effects of train/car noise on formants estimation. It is divided into two parts: –Effect of train/car noise on formant frequency estimation –Effect of train/car noise on formant tracking

4. Communications & Multimedia Signal Processing GenderF1 SNRF2 SNRF3 SNRF4 SNRF5 SNR Female-1.547.1410.3811.3312.16 Male-2.56.449.7410.338.73 Table : Formant SNR of car noisy speech (SNR=0) GenderF1 SNRF2 SNRF3 SNRF4 SNRF5 SNR Female-6.68-1.054.959.3011.75 Male-6.56-1.343.998.228.38 Table : Formant SNR of train noisy speech (SNR=0) Variation in Formant SNR F1 is the most affected by train/car noise and F5 is less effected. Female is less affected by train/car noise than male. Train noise has more impact on Formant SNR than car noise.

5. Communications & Multimedia Signal Processing Formant Estimation by 2D-HMM Formant candidate Feature vector Speech Segmentation & window LPC Model Polynomial roots Frequency, Bandwidth, Magnitude Calculation  estimator Source Speech Cepstral Feature Analysis LP Pole Analysis Speech HMMs Training Formant Features Extraction Speech Labelling & Segmentation Formant 2D HMMs Training Formant Tracking Formant Estimated values Formant Feature Extraction

6. Communications & Multimedia Signal Processing Formant Frequency Estimates in Train Noise F1 of different vowels is moving towards the high frequency around 620 Hz. F2,F3 and F4 is less affected by the noise.

7. Communications & Multimedia Signal Processing

8. Formant Frequency Estimates in Car Noise

9. Communications & Multimedia Signal Processing Effect of Train/Car Noise on Formant Tracking Figure : Red -- formant tracks from clean speech; Blue -- formant tracks from car noisy speech (SNR=0); Cyan -- formant tracks from train noisy speech (SNR=0) Formant tracks from train noisy speech is more affected than car noise speech at same SNR

10. Communications & Multimedia Signal Processing Future Work Robust estimation of clean formant tracks from train/car noisy speeches at various SNR conditions. -- LP subtraction. -- pole classification/separation. -- incorporated with other information such as temporal continuity. Robust estimation of clean pitch tracks from train/car noisy speeches.

11. Communications & Multimedia Signal Processing Thank you !