The objective of multiscale analysis is to study signal (time-scale) or image (scale-space) singularities at different scales or resolutions .
A powerful tool is the Wavelet Transform that works as derivative operator at different scales . It provides a compact representation of the original signal and allows to also exploit inter and intra scale redundancy of its coefficients. It is well-known its persinstency property: "large/small values of wavelet coefficients tend to propagate across scales" . It can be easily seen in the following images where there are the original image (Lena) and its wavelet coefficients.
An interesting problem is to link wavelet coefficients at a given (intra) scale and/or along (inter) scales, since many signal processing problems (compression, denoising, retrieval etc.) strongly depend on it.