Fumitada Itakura
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is a Japanese
scientist A scientist is a person who conducts scientific research to advance knowledge in an area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosoph ...
. He did pioneering work in
statistical signal processing Signal processing is an electrical engineering subfield that focuses on analyzing, modifying and synthesizing '' signals'', such as sound, images, and scientific measurements. Signal processing techniques are used to optimize transmissions, ...
, and its application to
speech analysis Voice analysis is the study of speech sounds for purposes other than linguistic content, such as in speech recognition. Such studies include mostly medical analysis of the voice (phoniatrics), but also speaker identification. More controversially ...
, synthesis and coding, including the development of the
linear predictive coding Linear predictive coding (LPC) is a method used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive mod ...
(LPC) and
line spectral pairs Line spectral pairs (LSP) or line spectral frequencies (LSF) are used to represent linear prediction coefficients (LPC) for transmission over a channel. LSPs have several properties (e.g. smaller sensitivity to quantization noise) that make them s ...
(LSP) methods.


Biography

Itakura was born in
Toyokawa is a city in the eastern part of Aichi Prefecture, Japan. , the city had an estimated population of 183,930 in 72,949 households, and a population density of 1,141 persons per km2. The total area of the city is . Toyokawa, famous for its Toyoka ...
,
Aichi Prefecture is a prefecture of Japan located in the Chūbu region of Honshū. Aichi Prefecture has a population of 7,552,873 () and a geographic area of with a population density of . Aichi Prefecture borders Mie Prefecture to the west, Gifu Prefectur ...
,
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. He received undergraduate and graduate degrees from Nagoya University in 1963 and 1965, respectively. In 1966, while studying his PhD at Nagoya, he developed the earliest concepts for what would later become known as
linear predictive coding Linear predictive coding (LPC) is a method used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive mod ...
(LPC), along with Shuzo Saito from
Nippon Telegraph and Telephone , commonly known as NTT, is a Japanese telecommunications company headquartered in Tokyo, Japan. Ranked 55th in ''Fortune'' Global 500, NTT is the fourth largest telecommunications company in the world in terms of revenue, as well as the third la ...
(NTT). They described an approach to automatic
phoneme In phonology and linguistics, a phoneme () is a unit of sound that can distinguish one word from another in a particular language. For example, in most dialects of English, with the notable exception of the West Midlands and the north-wes ...
discrimination that involved the first
maximum likelihood In statistics, maximum likelihood estimation (MLE) is a method of estimating the parameters of an assumed probability distribution, given some observed data. This is achieved by maximizing a likelihood function so that, under the assumed stat ...
approach to
speech coding Speech coding is an application of data compression of digital audio signals containing speech. Speech coding uses speech-specific parameter estimation using audio signal processing techniques to model the speech signal, combined with generic d ...
. In 1968, he joined the NTT Musashino Electrical Communication Laboratory in
Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...
. The same year, Itakura and Saito presented the
Itakura–Saito distance The Itakura–Saito distance (or Itakura–Saito divergence) is a measure of the difference between an original spectrum P(\omega) and an approximation \hat(\omega) of that spectrum. Although it is not a perceptual measure, it is intended to reflect ...
algorithm. The following year, Itakura and Saito introduced
partial correlation In probability theory and statistics, partial correlation measures the degree of association between two random variables, with the effect of a set of controlling random variables removed. When determining the numerical relationship between two ...
(PARCOR) to LPC. Itakura completed his
D.Eng. The Doctor of Engineering, or Engineering Doctorate, (abbreviated DEng, EngD, or Dr-Ing) is a degree awarded on the basis of advanced study and a practical project in the engineering and applied science for solving problems in the industry. In the ...
degree in
speech processing Speech processing is the study of speech signals and the processing methods of signals. The signals are usually processed in a digital representation, so speech processing can be regarded as a special case of digital signal processing, applied t ...
in 1972, writing his dissertation on "Speech Analysis and Synthesis based on a Statistical Method." From 1973 to 1975, he worked at the Acoustics Research Department of
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial Research and development, research and scientific developm ...
, having been invited to work there on fundamental problems by James Flanagan, who had been impressed by one of Itakura's papers on low bit-rate encoding. In 1975, Itakura developed the
line spectral pairs Line spectral pairs (LSP) or line spectral frequencies (LSF) are used to represent linear prediction coefficients (LPC) for transmission over a channel. LSPs have several properties (e.g. smaller sensitivity to quantization noise) that make them s ...
(LSP) method for high-compression speech coding, while at NTT. From 1975 to 1981, he studied problems in speech analysis and synthesis based on the LSP method. In 1980, his team developed an LSP-based speech synthesizer chip. LSP is an important technology for speech synthesis and coding, and in the 1990s was adopted by almost all international speech coding standards as an essential component, contributing to the enhancement of digital speech communication over mobile channels and the internet worldwide. In 1981, he was appointed as Chief of the Speech and Acoustics Research Section at NTT. He left this position in 1984 to take a professorship in communications theory and signal processing at Nagoya University. He currently teaches at
Meijo University is a private university in Japan. Its main campus is in Tempaku-ku, Nagoya, Aichi Prefecture, and it has two other campuses in Nagoya, Aichi Prefecture. It had two faculty members who were Nobel laureates as of 2021. History The name Meijō ...
. Itakura's work on spectral and formant estimation laid the foundation for much of the early progress in speech signal processing. His work on autoregressive modeling of speech is used in nearly every modern low-to-medium, bit-rate speech transmission system, and the line spectral pair representation he developed is now found in nearly all cellular telephone systems.


Awards

His awards include the IEEE ASSP 1975 Senior Award, an award from Japan's Ministry of Science and Technology in 1977, the IEEE 1986 Morris N. Liebmann Award (with B. S. Atal), the IEEE Signal Processing 1996 Society Award, the IEEE Third Millennium Medal, the IEICE 2002 Distinguished Achievement and Contributions Award, and the 2003 Purple Ribbon Medal from Japanese Government. In 2005, he received the
Asahi Prize The , established in 1929, is an award presented by the Japanese newspaper ''Asahi Shimbun'' and Asahi Shimbun Foundation to honor individuals and groups that have made outstanding accomplishments in the fields of arts and academics and have greatl ...
and the IEEE Jack S. Kilby Signal Processing Medal. In 2009, he received the NEC
C&C Prize The NEC C&C Prize ( ja, C&C賞) is an award given by the NEC Corporation "in recognition of outstanding contributions to research and development and/or pioneering work in the fields of semiconductors, computers, telecommunications and their integr ...
for his pioneering research and the development of highly efficient voice-coding technology with analysis-synthesis methods for speech. He is a Fellow of the
IEEE The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operat ...
and an honorary member the Institute of Electronics, Information and Communication Engineers of Japan.


References

{{DEFAULTSORT:Itakura, Fumitada 1940 births Living people People from Toyokawa, Aichi Scientists at Bell Labs Fellow Members of the IEEE Nagoya University faculty Nagoya University alumni Speech processing researchers