Industrial Applications of Wavelets

小林 メイ
日本 IBM (株)


During the past decade, wavelets have come to be recognized as branch of mathematical analysis. As the field had matured, a variety of highly pragmatic applications have been developed based on the theory. Quantitative evidence of the impact of wavelets on industry is the increase in wavelet-related patents which have been filed in the United States, Japan and Europe in the past two decades. I will note some of the trends in patent filings and some newsworthy examples. And I will review some wavelet-based technologies which appear in patents and/or which have been gainfully employed in system prototypes, commercial products and industrial design and manufacturing processes.

My work on wavelets has focussed on two areas: multiresolution representation of Japanese geographic data with Sumiko Hiyama of the Earthquake Research Institute of the University of Tokyo and digital speech synthesis using wavelet transform analysis with the Speech Group of IBM Tokyo Research Laboratory. The primary aim of the geographic data work was to develop a means to visualize Japanese coastline data at various resolution levels on standard PCs. We examined various types of wavelets to determine which were more suitable for compressing the data while preserving intricate features associated with coastline curves. In the second project, we developed new pitch marking and time dependent pitch synchronous overlap-add methods based on wavelet transform analysis. These methods improve the quality of synthesized speech when only a limited number of speech templates can be used. Our methods were adopted for use in a commercial text-to-speech product which received an Outstanding Technology Development Award from the Acoustical Society of Japan.