Apparatus and method for decomposing an audio signal using a variable threshold

A method of decomposing an audio signal into a background component signal and a foreground component signal, the method comprising:

• generating a time sequence of blocks of audio signal values of the audio signal, the time sequence of blocks comprising a current block of audio signal values and at least two blocks of audio signal values;
• determining a characteristic of the current block of the time sequence of blocks and determining a variability of the characteristic within a group of blocks comprising the at least two blocks of the time sequence of blocks;
• and
• separating the current block into a background portion and a foreground portion or determining the whole current block as either the foreground component signal or the background component signal,
• wherein a separation threshold is determined based on the variability of the characteristic, and
• wherein the current block is separated into the background component signal and the foreground component signal, when the characteristic of the current block is in a predetermined relation to the separation threshold determined based on the variability of the characteristic, or
• wherein the whole current block is determined as the foreground component signal, when the characteristic of the current block is in the predetermined relation to the separation threshold determined based on the variability of the characteristic, or
• wherein the whole current block is determined as the background component signal, when the characteristic of the current block is not in the predetermined relation to the separation threshold determined based on the variability of the characteristic.

A non-transitory digital storage medium having stored thereon a computer program for performing, when said computer program is run by a computer, a method of decomposing an audio signal into a background component signal and a foreground component signal, the method comprising:

• generating a time sequence of blocks of audio signal values of the audio signal, the time sequence of blocks comprising a current block of audio signal values and at least two blocks of audio signal values;
• determining a characteristic of the current block of the of the time sequence of blocks and determining a variability of the characteristic within a group of blocks comprising the at least two blocks of the time sequence of blocks;
• and
• separating the current block into a background portion and a foreground portion or determining the whole current block as either the foreground component signal or the background component signal,
• wherein a separation threshold is determined based on the variability of the characteristic, and
• wherein the current block is separated into the background component signal and the foreground component signal, when the characteristic of the current block is in a predetermined relation to the separation threshold determined based on the variability of the characteristic, or
• wherein the whole current block is determined as the foreground component signal, when the characteristic of the current block is in the predetermined relation to the separation threshold determined based on the variability of the characteristic, or
• wherein the whole current block is determined as the background component signal, when the characteristic of the current block is not in the predetermined relation to the separation threshold determined based on the variability of the characteristic.