1 Skin Perfusion Studies: Historical Notes and Modern Measuring …
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Fig. 1.15 Examples of transient signal analysis. Top: two different synthetic signals. Middle:
Fourier Transform of sample signals. Bottom: Wavelet transform of the same signals. The advantage
of the multidimensional time-frequency analysis can clearly be seen
The Wavelet transform of a signal leads to a three-dimensional time-frequency
representation where the spectral evolution over time can be assessed directly. It
is actually a family of transformations where a signal g(t) is transformed by an
analyzing function ψ(t). ψ(t), called the “mother wavelet”, can be chosen from
a collection of functions. All of these have to meet certain restraints (see [59]),
especially its localization in time and frequency domain.
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Fig. 1.15 Examples of transient signal analysis. Top: two different synthetic signals. Middle:
Fourier Transform of sample signals. Bottom: Wavelet transform of the same signals. The advantage
of the multidimensional time-frequency analysis can clearly be seen
The Wavelet transform of a signal leads to a three-dimensional time-frequency
representation where the spectral evolution over time can be assessed directly. It
is actually a family of transformations where a signal g(t) is transformed by an
analyzing function ψ(t). ψ(t), called the “mother wavelet”, can be chosen from
a collection of functions. All of these have to meet certain restraints (see [59]),
especially its localization in time and frequency domain.