Function DEFAULT_FILTER_OPTIONS

Package

Short description

Usage

    filt_opt = DEFAULT_FILTER_OPTIONS(filter_type, averaging_size)

Input

    filter_type (char): Either 'image' (for images), 'audio' (for audio
       signals) or 'dyadic' (for other, less oscillatory, 1D signals).
    averaging_size (numeric): The desired averaging size of the lowpass
       filter phi, that is, the maximal scale of the wavelets.

Output

    filt_opt (struct): A set of filter options to be given to the
        FILTER_BANK, WAVELET_FACTORY_1D or WAVELET_FACTORY_2D functions.

Description

    For images, Q is set to 1, giving dyadic wavelets, while J is set so that
    the lowpass filter phi is of size 2^J ~ averaging_size. For audio sig-
    nals, Q is set to 8 at the first layer, approximating the mel-frequency 
    scale. For other 1D signals (financial time series, physical measure-
    ments), Q is set to 1 at all layers, giving dyadic wavelets. In these two
    cases, J is computed through the utility T_TO_J.

See also

• filter_bank
• wavelet_factory_1d
• wavelet_factory_2d