Retrieves approximation or detail discrete wavelet transform (DWT) coefficients at a specific level. Use the WA Discrete Wavelet Transform VI to compute the DWT of a signal. Wire data to the DWT coef input to determine the polymorphic instance to use or manually select the instance.


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Inputs/Outputs

  • cu16.png coef type —

    coef type specifies the coefficient type this VI returns.

  • c1dcclst.png DWT coef —

    DWT coef specifies the approximation coefficients and the detail coefficients from the multi-level discrete wavelet transform. Each element of the array contains the 2D DWT results of one level. The ith element stores the approximation coefficients and the detail coefficients at level i+1.

  • c2ddbl.png low_low —

    low_low specifies the approximation coefficients from the lowpass analysis filtering on each row and each column. The low_low coefficients are a low-resolution approximation of the original 2D signal.

  • c2ddbl.png low_high —

    low_high specifies the detail coefficients from the lowpass analysis filtering on each row and the highpass analysis filtering on each column. The high-frequency signal along the column direction influences the low_high coefficients.

  • c2ddbl.png high_low —

    high_low specifies the detail coefficients from the highpass analysis filtering on each row and the lowpass analysis filtering on each column. The high-frequency signal along the row direction influences the high_low coefficients.

  • c2ddbl.png high_high —

    high_high specifies the detail coefficients from the highpass analysis filtering on each row and each column. The high-frequency signal along the diagonal direction influences the high_high coefficients.

  • ci32.png coef level —

    coef level specifies the coefficient level this VI returns. The coef level must be between 1 and the largest level of the coefficients. The levels in the WA Discrete Wavelet Transform VI specifies the largest level of the coefficients. The default is 1, which means this VI returns the coefficients at level 1.

  • cerrcodeclst.png error in (no error) —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • i1dcclst.png DWT coef out —

    DWT coef out returns DWT coef unchanged.

  • i2ddbl.png low_low out —

    low_low out returns the approximation coefficients from the lowpass analysis filtering on each row and each column. The low_low out coefficients are a low-resolution approximation of the original 2D signal.

  • i2ddbl.png low_high out —

    low_high out returns the detail coefficients from the lowpass analysis filtering on each row and the highpass analysis filtering on each column. The high-frequency signal along the column direction influences the low_high out coefficients.

  • i2ddbl.png high_low out —

    high_low out returns the detail coefficients from the highpass analysis filtering on each row and the lowpass analysis filtering on each column. The high-frequency signal along the row direction influences the high_low out coefficients.

  • i2ddbl.png high_high out —

    high_high out returns the detail coefficients from the highpass analysis filtering on each row and each column. The high-frequency signal along the diagonal direction influences the high_high out coefficients.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.

  • i2ddbl.png selected DWT coef —

    selected DWT coef returns the discrete wavelet transform (DWT) coefficients at the coefficient level coef level of the coefficient type coef type.

    • Examples

    Refer to the following VIs for examples of using the WA Get Coefficients of Discrete Wavelet Transform VI:

    • Get and Set Approximation Coefficients VI: labview\examples\Wavelet Analysis\WAGettingStarted
    • Get and Set Single Level Detail Coefficients VI: labview\examples\Wavelet Analysis\WAGettingStarted