Frequency thinning apparatus for thinning out frequency components of signal and frequency thinning apparatus

A frequency thinning apparatus, comprising:

• spectrum distribution generating means for generating the signal representing the frequency spectrum of a signal to be directed to frequency thinning processing;
• removal band decision means for determining correlation factors for all the possible combinations of selected two bands, determining, in decreasing order of the correlation factors, a predetermined number X of the combination among all the combinations of which the correlation factors have been determined, determines the X bands as removal bands by selecting, without duplication, one band as a removal band for each of the determined X combinations, and determining a band paired with the removal band as an interpolation band for each of the determined X combinations;
• and
• thinning compression means for substantially removing spectrum components in the removal bands by generating the spectrum signal having a continuous spectrum including the spectrum distribution of all sub-bands within said whole band except for the removal bands,
• wherein said removal band decision means further has means for outputting information indicative of the removal bands and the interpolation bands.

A frequency thinning method for performing compression of signal information by removing specified frequency components in a given time sequence signal, said method comprising the steps of:

• transforming the given time sequence signal into a frequency spectrum signal;
• determining correlation factors for all the possible combinations of selected two bands;
• determining, in decreasing order of the correlation factors, a predetermined number X of the combinations among all the combinations of which the correlation factors have been determined;
• determining the X bands as removal bands by selecting, without duplication, one band as a removal band for each of the determined X combinations;
• removing the frequency components in the removal bands;
• compressing the total length of a continuous spectrum distribution by shifting residual frequency components not removed toward the lower frequency side so as to reduce space in said removal bands;
• inversely transforming a spectrum signal having the reduced total length of said continuous spectrum distribution into a time sequence signal;
• and
• outputting information indicative of the removal bands.

A computer readable storage medium storing a program for making a computer function as,

• means for transforming a given time sequence signal into a frequency spectrum signal,
• removal band decision means for determining correlation factors for all the possible combinations of selected two bands, determining, in decreasing order of the correlation factors, a predetermined number X of the combinations among all the combinations of which the correlation factors have been determined, determining the X bands as removal bands by selecting, without duplication, one band as a removal band for each of the determined X combinations, and removing the frequency components in the removal bands,
• means for compressing the total length of a continuous spectrum distribution by shifting residual frequency components not removed toward the lower frequency side so as to reduce space in said removal bands, and
• means for inversely transforming a spectrum signal having the reduced total length of said continuous spectrum distribution into a time sequence signal, thereby compressing signal information by removing specified frequency components in the given time sequence signal.
• wherein said removal band decision means further has means for outputting information indicative of the removal bands.