Speech signal evaluation apparatus, storage medium storing speech signal evaluation program, and speech signal evaluation method

A computer-readable medium storing a speech signal evaluation program, which when executed by a computer, causes the computer to execute:

• acquiring, as a first frame, a speech signal of a specified length from speech signals stored in a memory;
• detecting, on the basis of a speech condition indicating a presence of speech in a frame, whether the first frame is voiced or unvoiced, an unvoiced frame does not satisfy the speech condition and a voiced frame does satisfy the speech condition;
• calculating, when the first frame is unvoiced, a variation in a spectrum associated with the first frame on the basis of a spectrum of the first frame and a spectrum of a second frame, the second frame being unvoiced and preceding the first frame in time;
• and
• detecting, on the basis of a non-stationary condition based on the variation in spectrum, whether the variation satisfies the non-stationary condition.

A speech signal evaluation method executed by a computer, the speech signal evaluation method comprising:

• acquiring, as a first frame, a speech signal of a specified length from speech signals stored in a memory;
• detecting, on the basis of a speech condition indicating a presence of speech in a frame, whether the first frame is voiced or unvoiced, an unvoiced frame does not satisfy the speech condition and a voiced frame does satisfy the speech condition;
• calculating, when the first frame is unvoiced, a variation in a spectrum associated with the first frame on the basis of a spectrum of the first frame and a spectrum of a second frame, the second frame being unvoiced and preceding the first frame in time;
• and
• detecting, on the basis of a non-stationary condition based on the variation in spectrum, whether the variation satisfies the non-stationary condition.