Noise reduction method and apparatus
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsFisseha Mekuria, Hans Cavander
Life of this patent
Estimating the term…
Abstract
Apparatuses for noise reduction and noise processing methods for reducing noise in audio signals are presented. The noise level of an input signal at an input terminal is measured and the noise-to-signal ratio is established. A reduced voice activity detector is used to determine whether the input signal comprises speech or not. If the measured noise level exceeds a threshold level a switch connects the input signal to means for noise reduction. However, if the measured noise level does not exceed the threshold level, i.e. when noise reduction is not needed, the switch disconnects the means for noise reduction and the input signal is passed unchanged. Power is saved by powering off the means for noise reduction when it is not needed.
Claims19
An apparatus for reducing noise comprising:
- an input terminal for receiving an input signal;
- a noise measurer connected to the input terminal and operable to measure a noise level of the input signal;
- a comparator for receiving the measured noise level from the noise measurer and operable to generate a first control signal by comparing the measured noise level with a first predetermined noise level;
- a switch connected to the input terminal and controlled by the first control signal generated by the comparator;
- and
- a noise reducer connected to the switch and operable to reduce noise within the input signal when said noise reducer is activated by the switch, wherein said first control signal is operable to control the switch so as to activate the noise reducer when the measured noise level is higher than the first predetermined noise level, and said first control signal is operable to control the switch so as to deactivate the noise reducer when the measured noise level is lower than the first predetermined noise level.
A noise processing method for reducing noise comprising the steps of:
- measuring a noise level of an input signal;
- determining if the measured noise level is lower than a first predetermined noise level;
- and
- providing the input signal as an output signal when the measured noise level is lower than said first predetermined noise level and, otherwise, performing noise reduction on the input signal and providing the so processed input signal as the output signal.
A noise processing method for reducing noise comprising the steps of:
- measuring a noise level of an input signal;
- determining if the measured noise level is lower than a first predetermined noise level or higher than a second predetermined noise level, said second predetermined noise level being higher than said first predetermined noise level;
- and
- providing the input signal as an output signal when the measured noise level is lower than said first predetermined noise level and, otherwise, performing noise reduction on the input signal and providing the so processed input signal as the output signal when the measured noise level is higher than or equal to said first predetermined noise level but lower than said second predetermined noise level and, otherwise, performing low pass filtering on said input signal and providing the so filtered input signal as the output signal when the measured noise level is higher than or equal to said second predetermined noise level.
Dependencies are inferred from the claim text.