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In mathematics, a wavelet series is a representation of a square-integrable (real- or complex-valued) function by a certain orthonormal series generated by a wavelet. Nowadays, wavelet transformation is one of the most popular of the time-frequency-transformations. This article provides a formal, mathematical definition of an orthonormal wavelet and of the integral wavelet transform. ==Definition== A function is called an orthonormal wavelet if it can be used to define a Hilbert basis, that is a complete orthonormal system, for the Hilbert space of square integrable functions. The Hilbert basis is constructed as the family of functions by means of dyadic translations and dilations of , : for integers . If under the standard inner product on , : this family is orthonormal, it is an orthonormal system: : where is the Kronecker delta. Completeness is satisfied if every function may be expanded in the basis as : with convergence of the series understood to be convergence in norm. Such a representation of a function ''f'' is known as a wavelet series. This implies that an orthonormal wavelet is self-dual. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Wavelet transform」の詳細全文を読む スポンサード リンク
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