Ravi P. Ramachandran

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Line spectral frequencies provide an alternate parameter-ization of the analysis and synthesis filters used in linear predictive coding (LPC) of speech. In this paper, a new method of converting between the direct form predictor coefficients and line spectral frequencies is presented. ,The system polynomial for the analysis filter is converted to two(More)
Prediction error filters which combine short-time prediction (formant prediction) with long-time prediction (pitch prediction) in a cascade connection are examined. A number of different solution methods (autocorrelation, covariance, Burg) and implementations (transversal and lattice) are considered. It is found that the F-P cascade (formant filter before(More)
Cochannel interference of speech signals is a common practical problem particularly in tactical communications. Ideally, separation of the individual speech signals is desired. However, it is known that when two equal bandwidth signals are added, such a separation is not possible. We examine the problem of identifying temporal regions or frames as being(More)
The future commercialization of speaker- and speech-recognition technology is impeded by the large degradation in system performance due to environmental differences between training and testing conditions. This is known as the "mismatched condition." Studies have shown [l] that most contemporary systems achieve good recognition performance if the(More)
Speaker recognition refers to the concept of recognizing a speaker by his=her voice or speech samples. Some of the important applications of speaker recognition include customer veriÿcation for bank transactions, access to bank accounts through telephones, control on the use of credit cards, and for security purposes in the army, navy and airforce. This(More)
This paper analyzes the stability and performance of pitch filters in speech coding when pitch prediction is combined with formant prediction. A computationally simple stability test based on a sufficient condition is formulated for pitch synthesis filters. For typical orders of pitch filters, this sufficient test is very tight. Based on the test, a simple(More)
Vehicle reidentification is the process of matching vehicles from one point on the roadway (one field of view) to the next. By performing vehicle reidentification, important traffic parameters including travel time, travel time variability, section density, and partial dynamic origin/destination demands can be obtained. Field traffic data were collected in(More)