Digital processing of speech signals

Principal characteristics of speech speech production models speech analysis and analysis-synthesis systems linear predictive coding (LPC) analysis speech coding speech synthesis speech recognition future directions of speech processing. Appendices: convolution and z-transform vector quantization algorithm neural nests.

Digital speech processing, synthesis, and recognition

Clinical Measurement Of Speech And Voice

Real-time detection of basic physiological parameters such as blood pressure and heart rate is an important target in wearable smart devices for healthcare. Among these, the core body temperature is one of the most important basic medical indicators of fever, insomnia, fatigue, metabolic functionality, and depression. However, traditional wearable temperature sensors are based upon the measurement of skin temperature, which can vary dramatically from the true core body temperature. Here, we demonstrate a three-dimensional (3D) printed wearable “earable” smart device that is designed to be worn on the ear to track core body temperature from the tympanic membrane (i.e., ear drum) based on an infrared sensor. The device is fully integrated with data processing circuits and a wireless module for standalone functionality. Using this smart earable device, we demonstrate that the core body temperature can be accurately monitored regardless of the environment and activity of the user. In addition, a microphone an...

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3D Printed “Earable” Smart Devices for Real-Time Detection of Core Body Temperature

Supervisory control environments, such as the NASA control room can induce high workload levels in situations where a single error is capable of costing millions of dollars. An intelligent system can improve human supervisor performance by monitoring the human's workload levels and intelligently adapting the system capabilities, such as adapting the interaction medium or reallocating roles and responsibilities between the human and the system. Systems capable of responding promptly and accurately to the human's changes in workload require a workload assessment algorithm that can detect changes to all components of workload in real time. A review of 24 workload assessment algorithms across six task domains is provided. Each algorithm is reviewed based on four criteria: sensitivity, diagnosticity, suitability, and generalizability. The majority of the reviewed algorithms were developed for a specific task domain and are unable to generalize different tasks. Further, the majority of the algorithms do not account for individual differences, only assess one or two workload components, and do not classify underload.

A Survey of Workload Assessment Algorithms

The major drawback in the code excited linear prediction (CELP) type vocoders is their large computational requirements. In the present paper a simple method is proposed to reduce the pitch searching time in the pitch filter almost without degradation of quality. Based upon the observational regularity of the correlation function of speech, the searching range can be restricted to the positive side in pitch search. This is done by skipping the negative side with the width which is estimated from the previous positive envelope. In addition to that, the maximum number of available lags can be limited by the threshold, LT, which is set on 58 empirically. So, only the limited numbers of lags are considered in pitch search, which is less than a half of that of the full search method. By using the proposed method in pitch search, its required computations are greatly reduced. Experimental results show 51% time reduction almost without lowering the speech quality in segmental SNR measures. >

A fast pitch searching algorithm using correlation characteristics in CELP vocoder

The present invention relates to the method to receive a speech signal, to perform a recognition weighting process on it, to synthesize a synthetic speech signal, to calculate an autocorrelation of the synthetic speech signal whose delay is a predetermined value and an autocorrelation whose delay is 0, to divide the square of the former by the latter, to calculate a pitch lag and a pitch filter coefficient by calculating only the part of a positive peak with skipping over the part of a negative peak by using the results from the dividing operation, and to calculate and output the pitch lag and the pitch filter coefficient by repeating the above process Thus, real-time implementation of CELP vocoder can be achieved.

Method for reducing pitch search time for vocoder

To find the optimum pitch lag in a CELP vocoder with reduced computation requirement, a new pitch search algorithm is proposed. This algorithm is based on the sign of the abbreviated correlation function and agrees with that of the original correlation function. The abbreviated correlation function makes it possible to confine the candidates for the optimum pitch to the positively correlated lags, which reduces the computation load considerably. However, since the optimum pitch can be found without omission, the degradation of segmental SNR (SEGSNR) does not occur with the proposed algorithm. Experimental results show that the proposed algorithm can achieve 40% of computation time reduction compared to the conventional full search method.

http://ieeexplore.ieee.org/iel3/4198/12335/00569429.pdf

A new fast pitch search algorithm using the abbreviated correlation function in CELP vocoder

A fast vector quantization encoding algorithm using multiple projection axes

When a person is drunk, lung capacity, lung movement velocity and air pulse change. Drunken people show unique characteristics especially in their speeches with respect to the spectrum area because they tend to speak more forcefully. In other words, the spectrum in the low frequency band area and high frequency band area become relatively flat. This paper suggests that it is possible to develop a sobriety test using speech analysis based on formant energy distribution. The test utilizes the errors in forming the formant envelope between high order linear prediction coding and low order linear prediction coding. About 65% accuracy was obtained in determining whether or not a person is sober by this method.

Myung-Jin Bae

Papers

A fast pitch searching algorithm using correlation characteristics in CELP vocoder

Method for reducing pitch search time for vocoder

A new fast pitch search algorithm using the abbreviated correlation function in CELP vocoder

A fast vector quantization encoding algorithm using multiple projection axes

Speech sobriety test based on formant energy distribution