1. Field
Example embodiments of the following description relate to a signal processing apparatus and method, and more particularly, to a signal processing apparatus and method for providing a 3-dimensional (3D) sound effect by separating an input signal into a primary signal and an ambience signal.
2. Description of the Related Art
In order to apply a 3-dimensional (3D) sound effect to an audio signal, an ambience signal that corresponds to a background signal and noise needs to be extracted from an input signal. Conventionally, the ambience signal to be extracted from the input signal is determined by a coherence value of a predetermined section. In a physical sense, the coherence value refers to a statistical value of interference between two signals in the predetermined section.
Extraction of the ambience signal based on the coherence of the predetermined section may be efficient in a relatively simple signal. However, in a variable signal, it is difficult to quickly determine similarity. Therefore, noise may be mixed into a separated primary signal, or separation of the ambience signal and the primary signal may not be performed accurately.
Furthermore, when the coherence is extracted according to a conventional method, a phase difference between a left signal and a right signal of the input signal may not be reflected correctly. According to conventional art, since the coherence always has a value greater than or equal to 0 and less than or equal to a positive value of 1, although the phase of the left signal is 1+j and the phase of the right signal is −1−j, that is, opposite to the left signal, the coherence becomes 1. That is, the phase difference between the left signal and the right signal may not be properly reflected.
Accordingly, there is a demand for a method of reflecting a phase difference of an input signal while quickly extracting an ambience signal, even from a variable signal.