- Physical interpretation: To develop a physical intuition, this article might be informative:
The power spectrum of the Mellin transformation with applications to scaling of physical quantities
The Mellin transform is used to diagonalize the dilation operator in a manner analogous to the use of the Fourier transform to diagonalize the translation operator. A power spectrum is also introduced for the Mellin transform which is analogous to that used for the Fourier transform. Unlike the case for the power spectrum of the Fourier transform where sharp peaks correspond to periodicities in translation, the peaks in the power spectrum of the Mellin transform correspond to periodicities in magnification.
For this reason the Mellin transform is also referred to as the "scale transform" (just as the Fourier transform is called a frequency transform). Just as the Fourier transform is insensitive (in absolute value) to a translation, the Mellin transform is insensitive (in absolute value) to a magnification.
- Applications in radar engineering: A classic application of the Mellin transform is in radar technology. Recall that the resolution in time of a signal is the reciprocal of the spread of its Fourier transform. In radar (or sonar) a signal is reflected from a moving target and you would like to accurately determine its velocity. The velocity resolution of the signal is the reciprocal of the spread of its Mellin transform. This application is worked out in:
- Applications in pattern recognition: The invariance properties of the Mellin and Fourier transforms can be combined in the socalled Fourier-Mellin transform to detect for rotation and scale invariant patterns. This combination is realized by a logarithmic mapping followed by a Fourier transformation, and it is believed that the visual cortex operates in this way.