Method for carrying out integer approximation of transform coefficients, and coder and decoder
AssigneeRobert Bosch GmbH
InventorsClaudia Mayer, Mathias Wien
Life of this patent
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Abstract
A limited value range is defined for obtaining approximated integer cosine transform coefficients. The transform coefficients of the base vectors for the submatrices are selected by taking into account the orthogonality condition so that the sum of their squares yields the square of the constant component coefficient. The coefficients of the variable components are derived from these coefficients. These measures yield the advantage that in quantization and normalization, a uniform normalization and quantization factor may be used for all coefficients.
Claims14
A method of obtaining approximated integer cosine transform coefficients, comprising:
- selecting the transform coefficients by:
- defining a limited value range for the transform coefficients,
- selecting coefficients of base vectors for submatrices by taking into account an orthogonality condition, so that a sum of squares of the coefficients of the base vectors yields a square of a constant component coefficient, and
- deriving coefficients of variable components from the coefficients of the base vectors.
A coder for frequency range coding of a moving image sequence, comprising:
- a transform device for creating transform coefficients for the moving image sequence, wherein the transform coefficients are processed by:
- defining a limited value range for the transform coefficients,
- selecting coefficients of base vectors for submatrices by taking into account an orthogonality condition, so that a sum of squares of the coefficients of the base vectors yields a square of a constant component coefficient, and
- deriving coefficients of variable component from the coefficients of the base vectors.
A decoder for frequency range decoding of a moving image sequence, comprising:
- a transform device for reconstructing a moving image sequence from transform coefficients created by:
- defining a limited value range for the transform coefficients, selecting coefficients of base vectors for submatrices by taking into account an orthogonality condition, so that a sum of squares of the coefficients of the base vectors yields a square of a constant component coefficient, and
- deriving coefficients of variable components from the coefficients of the base vectors.
Dependencies are inferred from the claim text.