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US 8,577,482 B2Granted
Device and method for generating an ambience signal
AssigneeFraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
InventorsJuergen Herre, Stefan Geyersberger, Oliver Hellmuth, Andreas Walther, Christiaan Janssen
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Abstract
A transient detector is provided for generating an ambience signal suitable for being emitted via loudspeakers for which there is no special loudspeaker signal to detect a transient period. A synthesis signal generator produces a synthesis signal which fulfills the transient condition on the one hand and the continuity condition for the synthesis signal on the other hand. A signal substituter will then substitute a portion of the examination signal by the synthesis signal to obtain an ambience signal for the surround channels.
Claims34
A device for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- a transient detector for detecting a transient period in which an examination signal comprises a transient region;
- a synthesis signal generator for generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- a signal substituter for substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein the transient detector is implemented to calculate high-frequency contents for a block of the examination signal;
- wherein the transient detector is implemented to compare the weighted high frequency contents to a floating average value over a plurality of preceding or subsequent blocks without any transients, and
- wherein the transient detector is implemented to detect a transient for a block when the high frequency contents of a current block exceeds the floating average value by more than a threshold.
4 more elements
A method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- detecting, by a transient detector, a transient period in which an examination signal comprises a transient region;
- generating, by a synthesis signal generator, a synthesis signal for the transient period, wherein the synthesis signal comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting, by a signal substituter, the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein, in detecting the transient, a high-frequency contents for a block of the examination signal is calculated;
- wherein, in detecting the transient, the weighted high frequency contents is compared to a floating average value over a plurality of preceding or subsequent blocks without any transients,
- wherein, in detecting the transient, the transient detector is implemented to detect a transient for a block when the high frequency contents of a current block exceeds the floating average value by more than a threshold, and
- wherein at least one of the transient detector the synthesis signal generator, and the signal substituter comprises a hardware implementation.
5 more elements
A non-transitory storage medium having stored thereon a computer program for executing a method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, when the method runs on a computer, the method comprising:
- detecting a transient period in which an examination signal comprises a transient region;
- generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal, wherein, in detecting the transient, a high-frequency contents for a block of the examination signal is calculated;
- wherein, in detecting the transient, the weighted high frequency contents is compared to a floating average value over a plurality of preceding or subsequent blocks without any transients,
- wherein, in detecting the transient, the transient detector is implemented to detect a transient for a block when the high frequency contents of a current block exceeds the floating average value by more than a threshold.
3 more elements
A device for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- a transient detector for detecting a transient period in which an examination signal comprises a transient region;
- a synthesis signal generator for generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- a signal substituter for substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein the device is implemented for block processing to process subsequent blocks of time-discrete samples in an overlapping or non-overlapping manner,
- wherein the transient detector is implemented to calculate intensity values for subsequent blocks and to detect a transient period when an intensity value of a block differs from a preceding or subsequent intensity value by more than a predetermined transient threshold, and
- wherein the synthesis signal generator is implemented to randomize complex spectral values representing a short-term spectrum of the block including the transient period with regard to their phases or signs.
4 more elements
A device for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- a transient detector for detecting a transient period in which an examination signal comprises a transient region;
- a synthesis signal generator for generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- a signal substituter for substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein the synthesis signal generator is implemented to calculate the synthesis signal from signal portions of the examination signals before or after the transient period, from the examination signal in the transient period after smoothing the temporal course thereof or from a combination of the signal portions of the examination signal and the examination signal after smoothing, and
- wherein the synthesis signal generator is implemented to copy signal portions of the examination signal before or after the transient period.
3 more elements
A device for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- a transient detector for detecting a transient period in which an examination signal comprises a transient region;
- a synthesis signal generator for generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- a signal substituter for substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein the synthesis signal generator is implemented to calculate the synthesis signal from signal portions of the examination signals before or after the transient period, from the examination signal in the transient period after smoothing the temporal course thereof or from a combination of the signal portions of the examination signal and the examination signal after smoothing, and
- wherein the synthesis signal generator is implemented to randomize, in a predetermined domain, extrapolated spectral values derived from the examination signal outside the transient period.
3 more elements
A device for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- a transient detector for detecting a transient period in which an examination signal comprises a transient region;
- a synthesis signal generator for generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- a signal substituter for substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein the synthesis signal generator is implemented to mix, when the transient period comprises longer a duration than a predetermined time, for times later than the predetermined period, synthesis signal values with signal values of the examination signal.
2 more elements
A device for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- a transient detector for detecting a transient period in which an examination signal comprises a transient region;
- a synthesis signal generator for generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- a signal substituter for substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein the signal substituter is implemented to cross-fade from a portion before the transient period to the transient period according to a cross-fade function or to cross-fade from the transient period to a portion after the transient period according to a cross-fade function.
2 more elements
A device for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- a transient detector for detecting a transient period in which an examination signal comprises a transient region;
- a synthesis signal generator for generating a synthesis signal for the transient period, the synthesis signal generator being implemented to generate a synthesis signal which comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- a signal substituter for substituting the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- a two-to-three mixer for generating a left channel, a right channel and a center channel from a stereo or mono signal transmitted;
- and
- wherein the synthesis signal generator is implemented to provide the same ambience signal for the back left and back right channels or to scale the examination signal so that the back left channel and the back right channel may receive different scaled versions of the ambience signal, or to calculate two special ambience signals for two surround channels.
4 more elements
A method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- detecting, by a transient detector, a transient period in which an examination signal comprises a transient region;
- generating, by a synthesis signal generator, a synthesis signal for the transient period, wherein the synthesis signal comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting, by a signal substituter, the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein the method is implemented for block processing to process subsequent blocks of time-discrete samples in an overlapping or non-overlapping manner,
- wherein, in detecting the transient, intensity values for subsequent blocks are calculated and a transient period is detected when an intensity value of a block differs from a preceding or subsequent intensity value by more than a predetermined transient threshold, and
- wherein, in generating the synthesis signal, complex spectral values representing a short-term spectrum of the block including the transient period are randomized with regard to their phases or signs, and
- wherein at least one of the transient detector, the synthesis signal generator, and the signal substituter comprises a hardware implementation.
5 more elements
A method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- detecting, by a transient detector, a transient period in which an examination signal comprises a transient region;
- generating, by a synthesis signal generator, a synthesis signal for the transient period, wherein the synthesis signal comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting, by a signal substituter, the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein, in generating the synthesis signal, the synthesis signal is calculated from signal portions of the examination signals before or after the transient period, from the examination signal in the transient period after smoothing the temporal course thereof or from a combination of the signal portions of the examination signal and the examination signal after smoothing, and
- wherein, in generating the synthesis signal, signal portions of the examination signal before or after the transient period are copied, and
- wherein at least one of the transient detector, the synthesis signal generator, and the signal substituter comprises a hardware implementation.
4 more elements
A method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- detecting, by a transient detector, a transient period in which an examination signal comprises a transient region;
- generating, by a synthesis signal generator, a synthesis signal for the transient period, wherein the synthesis signal comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting, by a signal substituter, the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein, in generating the synthesis signal, the synthesis signal is calculated from signal portions of the examination signals before or after the transient period, from the examination signal in the transient period after smoothing the temporal course thereof or from a combination of the signal portions of the examination signal and the examination signal after smoothing, and
- wherein, in generating the synthesis signal, extrapolated spectral values derived from the examination signal outside the transient period are randomized in a predetermined domain, and
- wherein at least one of the transient detector, the synthesis signal generator, and the signal substituter comprises a hardware implementation.
4 more elements
A method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- detecting, by a transient detector, a transient period in which an examination signal comprises a transient region;
- generating, by a synthesis signal generator, a synthesis signal for the transient period, wherein the synthesis signal comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting, by a signal substituter, the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein, in generating the synthesis signal, when the transient period comprises longer a duration than a predetermined time, for times later than the predetermined period, synthesis signal values are mixed with signal values of the examination signal, and
- wherein at least one of the transient detector, the synthesis signal generator, and the signal substituter comprises a hardware implementation.
3 more elements
A method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- detecting, by a transient detector, a transient period in which an examination signal comprises a transient region;
- generating, by a synthesis signal generator, a synthesis signal for the transient period, wherein the synthesis signal comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting, by a signal substituter, the examination signal in the transient period by the synthesis signal to obtain the ambience signal,
- wherein, when substituting the examination signal, it is cross-faded from a portion before the transient period to the transient period according to a cross-fade function or it is cross-faded from the transient period to a portion after the transient period according to a cross-fade function, and
- wherein at least one of the transient detector, the synthesis signal generator, and the signal substituter comprises a hardware implementation.
3 more elements
A method for generating an ambience signal suitable for being emitted via loudspeakers for which there is no suitable loudspeaker signal, comprising:
- detecting, by a transient detector, a transient period in which an examination signal comprises a transient region;
- generating, by a synthesis signal generator, a synthesis signal for the transient period, wherein the synthesis signal comprises a flatter temporal course than the examination signal in the transient period and the intensity of which deviates from an intensity of a preceding or subsequent portion of the examination signal by less than a predetermined threshold;
- and
- substituting, by a signal substituter, the examination signal in the transient period by the synthesis signal to obtain the ambience signal;
- generating a left channel, a right channel and a center channel from a stereo or mono signal transmitted by a two-to-three mixer;
- and
- wherein, in generating the synthesis signal, the same ambience signal for the back left and back right channels is provided or the examination signal is scaled so that the back left channel and the back right channel may receive different scaled versions of the ambience signal, or two special ambience signals are calculated for two surround channels,
- wherein at least one of the transient detector, the synthesis signal generator, the signal substituter, and the two-to-three mixer comprises a hardware implementation.
5 more elements
Dependencies are inferred from the claim text.