Audio data hiding based on perceptual masking and detection based on code multiplexing
AssigneeDolby Laboratories Licensing Corporation
InventorsRegunathan Radhakrishnan, Michael Smithers, David S. McGrath
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Abstract
A spread spectrum data hiding for audio signals is described. A set of pseudo-random noise sequences is added to an audio signal according to a data to be embedded. A masking curve is used to shape the added noise. A transient detection step can be used to control whether a shaped noise sequence is to be added or not. Embedded information is detected by first performing a whitening step and then performing a phase-only correlation with a same set of pseudo-random noise sequences. A detection method that is based on correlation of multiplexed noise sequences with a noise sequence embedded in the audio is also described.
Claims20
A computer-implemented method to embed data in an audio signal, comprising:
- selecting a pseudo-random sequence according to desired data bits to be embedded in an audio frame;
- shaping a frequency spectrum of the pseudo-random sequence, thus obtaining a shaped frequency spectrum of the pseudo-random noise sequence;
- detecting, for audio signal frames, presence or absence of transients;
- and
- adding the shaped frequency spectrum of the pseudo-random noise sequence to a frequency spectrum of the audio signal, the adding occurring on an audio signal frame by audio signal frame basis, wherein, for audio signal frames for which presence of a transient is detected, the shaped frequency spectrum of the pseudo-random noise sequence is not added to the frequency spectrum of the audio signal.
A non-transitory computer-readable storage medium having stored thereon computer-executable instructions executable by a processor to detect embedded data in an audio signal, comprising:
- performing a phase-only correlation between a frequency spectrum of the audio signal with embedded data and a noise sequence;
- and
- performing a detection decision based on a result of the phase-only correlation, wherein the data embedded in the audio signal is embedded according to a method comprising:
- selecting a pseudo-random sequence according to desired data bits to be embedded in an audio frame;
- shaping a frequency spectrum of the pseudo-random sequence, thus obtaining a shaped frequency spectrum of the pseudo-random noise sequence;
- detecting, for audio signal frames, presence or absence of transients;
- and
- adding the shaped frequency spectrum of the pseudo-random noise sequence to a frequency spectrum of the audio signal, the adding occurring on an audio signal frame by audio signal frame basis, wherein, for audio signal frames for which presence of a transient is detected, the shaped frequency spectrum of the pseudo-random noise sequence is not added to the frequency spectrum of the audio signal.
A system to embed data in an audio signal, the system comprising:
- a processor configured to:
- select a pseudo-random sequence according to desired data bits to be embedded in an audio frame;
- shape a frequency spectrum of the pseudo-random sequence, thus obtaining a shaped frequency spectrum of the pseudo-random noise sequence;
- detect, for audio signal frames, presence or absence of transients;
- and
- add the shaped frequency spectrum of the pseudo-random noise sequence to a frequency spectrum of the audio signal, the adding occurring on an audio signal frame by audio signal frame basis, wherein, for audio signal frames for which presence of a transient is detected, the shaped frequency spectrum of the pseudo-random noise sequence is not added to the frequency spectrum of the audio signal.
Dependencies are inferred from the claim text.