7.00.02 - IDWT2D - Aster Analytics

Teradata Aster® Analytics Foundation User GuideUpdate 2

Aster Analytics
Release Number
September 2017
Content Type
Programming Reference
User Guide
Publication ID
English (United States)
Last Update

The IDWT2D function is the inverse of DWT2D; that is, IDWT2D applies inverse wavelet transforms on multiple sequences simultaneously. IDWT2D takes as input the output table and meta table generated by DWT2D and outputs the sequences as 2-dimensional matrices. (Because the IDWT2D output is comparable to the DWT2D input, the inverse transformation is also called the reconstruction.)

A typical IDWT2D use case is:

  1. Apply DWT2D to 2-dimensional sequences to generate the coefficients of the matrices and corresponding metadata.
  2. Filter the coefficients by methods appropriate for the objects (for example, minimum threshold or top n coefficients), compressing the original matrices.
  3. Apply IDWT to the filtered coefficients to reconstruct the sequences.
  4. Compare the reconstructed matrices to their original counterparts.