dmusic(1)

PROGRAM
dmusic - 1D MUSIC Spectral Estimation

SYNTAX

dmusic

-i  input file (xviff file)

-o  resulting output file (xviff file)

[-s]
    model order (same as number of eigenvectors)

[-f]
    specify number of spectral values desired

[-p]
    do not center the psd estimate (0) or center the psd estimate (1)

[-j]
    scalar processing (0) or vector processing (1)

[-d]
    data processing direction (0 = down vectors, 1 = across bands)

[-g]
    type of autocorrelation file to be used:
    0 (choose biased autocorrelation estimate),
    1 (choose unbiased autocorrelation estimate),
    or 2 (choose FFT based autocorrelation estimate)
       [default = 0]

[-c]
    Use AIC (0) or MDL(1) criterion
    -OR-

[-k]
    dimension of noise subspace sequence

[-V]
    Gives the version for dmusic

[-U]
    Gives the usage for dmusic

[-P]
    Prompts for command line options

[-A [file1]]
    Creates the answer file called dmusic.ans or file1

[-a [file1]]
    Uses dmusic.ans or file1 as the answer file

DESCRIPTION
An implementation of the MUSIC (Multiple Signal Classification) for spectral estimation. MUSIC is a spectral estimation technique based on eigendecomposition of the autocorrelation matrix of a sampled random process.

The process involves generating estimates of the eigenvalues and eigenvectors of a Toelitz and Hermitian autocorrelation matrix estimate. The eigenvectors are then sorted by ascending order of their corresponding eigenvalues. The eigenvectors corresponding to the k smallest, approximately equal eigenvalues are selected. k is the dimension of the noise subspace, and can be specified by the user or may be computed using the Akaike (AIC) or Minimum Description Length (MDL) information theoretic criteria.

k power spectrum estimates corresponding to the k selected eigenvectors are computed and averaged to form the MUSIC power spectrum estimate.

For a more theoretical discussion of the MUSIC algorithm see: Optimum Signal Processing by Sophocles Orfranidis, McGraw-Hill, 1988; or Eigenvector-Based Parametric Modeling of Time-Domain Signals: Application to Nuclear Magnetic Resonance Spectroscopy by Glen Abousleman (Master's thesis, University of New Mexico, Dept. of EECE, 1990).

dmusic does not work on explicit location data and will return an error when such a file is encountered. No output file will be created. dmusic works only on VFF_TYP_FLOAT or VFF_TYP_COMPLEX data files.

Input/Output Files

The input file must be of type VFF_TYP_FLOAT or VFF_TYP_COMPLEX. The output file returned will be of size specified by the user. If the data is of type VFF_TYP_COMPLEX and complex aithmetic is selected then the output file will be of type VFF_TYP_FLOAT. *********************************************************************

Process direction

Data can be processed with either band or vector orientation (-d option). The default data processing direction is in the vector direction (-d = 0). pixel location. The direction of processing can be changed so that each band is processed as a signal (instead of each vector being a signal) by setting the -d option to 1.

REQUIRED ARGUMENTS

-i  type: infile
    desc: input file (xviff file)

-o  type: outfile
    desc: resulting output file (xviff file)

OPTIONAL ARGUMENTS

-s  type: integer
    desc: model order (same as number of eigenvectors)
    default: 1
    bounds: value > 0

-f  type: integer
    desc: specify number of spectral values desired
    default: 1
    bounds: value > 0

-p  type: boolean
    desc: do not center the psd estimate (0) or center the psd estimate (1)
    default: false

-j  type: boolean
    desc: scalar processing (0) or vector processing (1)
    default: true

-d  type: boolean
    desc: data processing direction (0 = down vectors, 1 = across bands)
    default: true

-g  type: integer
    desc: type of autocorrelation file to be used
    allowed values:
    0 (choose biased autocorrelation estimate),
    1 (choose unbiased autocorrelation estimate),
    or 2 (choose FFT based autocorrelation estimate)

*** These arguments are MUTUALLY EXCLUSIVE ***
 If desired, you may provide ONE AND ONLY ONE of:

-c  desc: Use AIC (0) or MDL(1) criterion
    default: false

-k  desc: dimension of noise subspace sequence
    default: 1
    bounds: value >= 0
    ********

EXAMPLES

SEE ALSO
intro(1), verror(3), vgparms(3), vutils(3), ldmusic(3)

RESTRICTIONS
works only on VFF_TYP_COMPLEX and VFF_TYP_FLOAT.

dmusic does not work on explicit location data and will return an error when such a data file is encountered.

COPYRIGHT
Copyright 1992, University of New Mexico. All rights reserved.