| 摘要 |
A method and apparatus is disclosed for determining a masked threshold curve as a function of frequency from an information signal. The method comprises a first step of determining for each frequency value a first masking component MC(1,k) at said frequency value f(k) resulting from a frequency component at said frequency value and having a magnitude equal to the magnitude value PV(k) of the magnitude spectrum at said frequency value, a second step of determining for subsequent frequency values when going in one direction through the frequency range of interest a second masking component MC(2,k) at a frequency value, the second masking component for said frequency value being determined from the first masking component MC(1,k-1) and the second masking component MC(2,k-1) at only the frequency value directly preceding said frequency value f(k-1), a third step of determining for subsequent frequency values when going in the reverse direction through the frequency range of interest a third masking component MC(3,k) at a frequency value, the third masking component for said frequency value being determined from masking information that has a relation to at least the first masking component MC(1,k+1) and the third masking component MC(3,k+1) at only the frequency value f(k+1) directly preceding said frequency value, a fourth step for determining a masking value MV(k) for a frequency value in said masked threshold curve from masking information that has a relation to said first, second and third masking components (if present) for said frequency value.
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