Wavelet analysis of scattered light intensity fluctuations was used to improve performance of speckle correlometry of porous systems. The further development of technique was proposed to study structural characteristics of such systems. The intensity fluctuations of multiple-scattered light is a non-stationary noise-like signal. Previously reported spectral analysis of such signals based on windowed Fourier transformation faces the well-known difficulties in a case of short time series. The effect of aliasing in frequency domain prevent us from determining spectral characteristics accurately. But by use of continuous wavelet analysis it can be defined with maximal time-frequency resolution.