(Press-News.org) Help is on the way for people who suffer from vocal cord dysfunction. Researchers are developing methods that will contribute to manufacturing voice prostheses with improved affective features. For example, for little girls who have lost their voices, the improved artificial voice devices can produce age-appropriate voices, instead of the usual voice of an adult male. These advances in artificial voice production have been made possible by results achieved in a research project led by Professor Samuli Siltanen, results that are good news indeed for the approximately 30,000 Finns with vocal cord problems. Siltanen's project is part of the Academy of Finland's Computational Science Research Programme (LASTU).
One of the fundamental problems of speech signal analysis is to find the vocal cord excitation signal from a digitally recorded speech sound and to determine the shape of the vocal tract, i.e. the mouth and the throat. This so-called glottal inverse filtering of the speech signal requires a highly specialised form of computer calculation. With traditional techniques, inverse filtration is only possible for low-pitch male voices. Women's and children's voices are trickier cases as the higher pitch comes too close in frequency to the lowest resonance of the vocal tract. The novel inverse calculation method developed by Siltanen and his team significantly improves glottal inverse filtering in these cases.
Besides in speech synthesis, inverse filtering is needed in automatic speech recognition. In speech synthesis, a computer will transform text into synthetic speech. The old-fashioned way is to record individual words and play them one after the other, but this seldom produces natural-sounding speech.
"Most speech sounds are a result of a specific process. The air flowing between the vocal folds makes them vibrate. This vibration, if we could hear it, would produce a weird buzzing sound. However, as it moves through the vocal tract, that buzz is transformed into some familiar vowel," explains Siltanen.
Singing, says Siltanen, is a perfect example of this interplay between the vocal cord response and the vocal tract: "When we sing the vowel 'a' in different pitches, our vocal tracts remain unchanged but the frequency of the vocal cord excitation changes. On the other hand, we can also sing different vowels in the same pitch, whereby the shape of the tract changes and the excitation stays the same."
Speech recognition is widely used, for example, in mobile phones and automatic telephone services. High-quality glottal inverse filtering improves the success rate of speech recognition in noisy environments.
###More information:
Professor Samuli Siltanen, Department of Mathematics and Statistics, University of Helsinki, tel. +358 9 191 51420 or +358 40 594 3560, samuli.siltanen@helsinki.fi
Harri Auvinen, Tuomo Raitio, Samuli Siltanen, Paavo Alku: Utilizing Markov Chain Monte Carlo (MCMC) Method for Improved Glottal Inverse Filtering, to appear in the proceedings of InterSpeech 2012 conference, Portland, Oregon, USA, 9 Sep 2012.
Tuomo Raitio, Antti Suni, Hannu Pulakka, Martti Vainio, Paavo Alku: Utilizing glottal source pulse library for generating improved excitation signal for HMM-based speech synthesis. In CD Proceedings of the International Conference on Acoustics, Speech, and Signal Processing (ICASSP'11), Prague, Czech Republic, 22 May 2011.
Academy of Finland Communications
Communications Specialist Leena Vähäkylä
Tel. +358 29 533 5139
firstname.lastname(at)aka.fi
Voice prostheses can help patients regain their lost voice
2012-10-24
ELSE PRESS RELEASES FROM THIS DATE:
Unearthing a hidden dietary behavior
2012-10-24
Though it was identified as a disorder as early as the 14th century, pica, or the eating of non-food items, has for years believed to be all but non-existent in a few corners of the globe – a 2006 study that reviewed research on pica found just four regions – the South of South America, Japan, Korea and Madagascar –where the behavior had never been observed.
A new Harvard study, however, is showing that pica – and particularly geophagy, or the eating of soil or clay, is far more prevalent in Madagascar, and may be more prevalent worldwide, than researchers previously ...
Hypnosis helps hot flashes
2012-10-24
CLEVELAND, Ohio (October 24, 2012)—Hypnosis can help cut hot flashes by as much as 74%, shows a study supported by the National Center for Complementary and Alternative Medicine. This is the first controlled, randomized study of the technique to manage hot flashes, which affect as much as 80% of women who go through menopause. The study was published online this month in Menopause, the journal of the North American Menopause Society.
Controlled, randomized studies may pit an active drug against an inactive placebo pill. But it's hard to find a placebo for mind-body techniques. ...
Brainwave training boosts network for cognitive control and affects mind-wandering
2012-10-24
A breakthrough study conducted in Canada has found that training of the well-known brainwave in humans, the alpha rhythm, enhances a brain network responsible for cognitive-control. The training technique, termed neurofeedback, is being considered as a promising new method for restoring brain function in mental disorders. Using several neuroimaging methods, a team of researchers at the Western University and the Lawson Health Research Institute have now uncovered that functional changes within a key brain network occur directly after a 30-minute session of noninvasive, ...
Earth's magnetosphere behaves like a sieve
2012-10-24
ESA's quartet of satellites studying Earth's magnetosphere, Cluster, has discovered that our protective magnetic bubble lets the solar wind in under a wider range of conditions than previously believed.
Earth's magnetic field is our planet's first line of defence against the bombardment of the solar wind. This stream of plasma is launched by the Sun and travels across the Solar System, carrying its own magnetic field with it.
Depending on how the solar wind's interplanetary magnetic field – IMF – is aligned with Earth's magnetic field, different phenomena can arise ...
An eye for an eye, a tooth for a tooth
2012-10-24
This press release is available in German.
It all began with a harmless game of soccer among young men in northwestern Albania. After one of the players had been injured in a subsequent dispute, his team members shot a relative of the suspected attacker. Now the male members of the families involved in the blood feud do not dare leave their homes. Such vendettas and blood feuds occur in many societies, sometimes lasting for decades. The harm for the participants is enormous and lacks apparent benefit, as the participants often no longer remember what actually triggered ...
Lactation protein suppresses tumors and metastasis in breast cancer
2012-10-24
BUFFALO, N.Y. -- A protein that is necessary for lactation in mammals inhibits the critical cellular transition that is an early indicator of breast cancer and metastasis, according to research conducted at the University at Buffalo and Princeton University and highlighted as the cover paper in November issue of Nature Cell Biology.
"This is the first confirmed report that this protein, called Elf5, is a tumor suppressor in breast cancer," explains Satrajit Sinha, PhD, associate professor of biochemistry in the UB School of Medicine and Biomedical Sciences and a corresponding ...
Hot flashes can come back after SSRI
2012-10-24
CLEVELAND, Ohio (October 24, 2012)—Hot flashes and night sweats can return after women stop using escitalopram—an antidepressant—to treat these menopause symptoms, according to a study published online this month in Menopause, the journal of the North American Menopause Society. This is typical of stopping hormone therapy as well.
Not every woman who took escitalopram in this National Institutes of Health-supported study had her symptoms come back, however. Symptoms returned for only about one third of the women. These women were more likely than others to have had insomnia, ...
Expert advisory: VCU study finds simple prevention strategy reducing MRSA infections
2012-10-24
RICHMOND, Va. (Oct. 24, 2012) – High compliance with hand hygiene and focusing on other simple infection control measures on medical, surgical and neuroscience intensive care units resulted in reduced rates of methicillin-resistant Staphylococcus aureus (MRSA) infection by 95 percent in a nine-year study, according to research findings by Virginia Commonwealth University physicians presented during IDWeek 2012.
Most hospitals use vertical infection prevention strategies, which focus on culturing for patients harboring organisms such as MRSA and isolating those patients. ...
Risk factors in hospital readmissions among general surgery patients identified in study
2012-10-24
ATLANTA – Identifying risk factors in hospital readmissions could help improve patient care and hospital bottom lines, according to a study recently completed by Georgia State University's Experimental Economics Center and a team from the Emory University School of Medicine.
The study, supported by a $1.2 million, three-year award to Georgia State's Andrew Young School of Policy Studies and Emory School of Medicine from the National Institutes of Health's National Institute on Aging, identifies factors associated with hospital readmission within 30 days after surgery ...
Buffalo milk mozzarella or buffaloed consumers? New test can provide the answer
2012-10-24
Those tiny balls of boutique mozzarella cheese with the sticker-shock price tag beckoning from the dairy case — are they the real deal, mozzarella di Bufala Campana DOP, crafted from the milk of water buffaloes? Or are they really cheap fakes made from cow's milk? A new method described in ACS' Journal of Agricultural and Food Chemistry promises to provide the answer for mozzarella and other dairy products.
Barbara van Asch and colleagues explain that premium dairy products, such as imported specialty cheeses labeled with a designation of origin, are most vulnerable to ...