Signal Distortion Elimination Apparatus, Method, Program, and Recording Medium Having the Program Recorded Thereon

A signal distortion elimination apparatus that eliminates signal distortion of an observed signal to obtain a restored signal, said signal distortion elimination apparatus comprising:

• a whitening filter calculation means that outputs a whitening filter obtained by performing linear prediction analysis on said observed signal;
• a whitening filter application means that outputs a whitened signal by applying said whitening filter to said observed signal;
• an inverse filter application means that applies, when a predetermined iteration termination condition is met, a filter (hereinafter referred to as an inverse filter) to said whitened signal and outputs the results thereof as said restored signal, and applies, when said iteration termination condition is not met, said inverse filter to said whitened signal and outputs the results thereof as an ad-hoc signal;
• a prediction error filter calculation means that segments said ad-hoc signal into frames, and outputs a prediction error filter of each of said frames obtained by performing linear prediction analysis on said ad-hoc signal of each frame;
• an inverse filter calculation means that calculates said inverse filter such that the samples of a concatenation of innovation estimates of said respective frames (hereinafter referred to as an innovation estimate sequence) become mutually independent, where said innovation estimate of a single frame (hereinafter referred to as an innovation estimate) is the signal obtained by applying said prediction error filter of the corresponding frame to the ad-hoc signal of the corresponding frame, and outputs the inverse filter;
• and
• a control means that iteratively executes said inverse filter application means, said prediction error filter calculation means and said inverse filter calculation means until said iteration termination condition is met.

A signal distortion elimination method for eliminating signal distortion of an observed signal to obtain a restored signal, said signal distortion elimination method comprising:

• an inverse filter application step wherein an inverse filter application means applies, when a predetermined iteration termination condition is met, a filter (hereinafter referred to as an inverse filter) to said observed signal and outputs the results thereof as said restored signal, and applies, when said iteration termination condition is not met, said inverse filter to said observed signal and outputs the results thereof as an ad-hoc signal;
• a prediction error filter calculation step wherein a prediction error filter calculation means segments said ad-hoc signal into frames, and outputs a prediction error filter of each of said frames obtained by performing linear prediction analysis on said ad-hoc signal of each frame;
• and
• an inverse filter calculation step wherein an inverse filter calculation means calculates said inverse filter such that the samples of a concatenation of innovation estimates of said respective frames (hereinafter referred to as an innovation estimate sequence) become mutually independent, where said innovation estimate of a single frame (hereinafter referred to as an innovation estimate) is the signal obtained by applying said prediction error filter of the corresponding frame to the ad-hoc signal of the corresponding frame, and outputs the inverse filter;
• and
• a control step wherein a control means iteratively executes said inverse filter application steps, said prediction error filter calculation steps and said inverse filter calculation steps until said iteration termination condition is met.

A signal distortion elimination method for eliminating signal distortion of an observed signal to obtain a restored signal, said signal distortion elimination method comprising:

• a whitening filter calculation step wherein a whitening filter calculation means outputs a whitening filter obtained by performing linear prediction analysis on said observed signal;
• a whitening filter application step wherein a whitening filter application means outputs a whitened signal by applying said whitening filter to said observed signal;
• an inverse filter application step wherein an inverse filter application means applies, when a predetermined iteration termination condition is met, a filter (hereinafter referred to as an inverse filter) to said whitened signal and outputs the results thereof as said restored signal, and applies, when said iteration termination condition is not met, said inverse filter to said whitened signal and outputs the results thereof as an ad-hoc signal;
• a prediction error filter calculation step wherein a prediction error filter calculation means segments said ad-hoc signal into frames, and outputs a prediction error filter of each of said frames obtained by performing linear prediction analysis on said ad-hoc signal of each frame;
• an inverse filter calculation step wherein an inverse filter calculation means calculates said inverse filter such that the samples of a concatenation of innovation estimates of said respective frames (hereinafter referred to as an innovation estimate sequence) become mutually independent, where said innovation estimate of a single frame (hereinafter referred to as an innovation estimate) is the signal obtained by applying said prediction error filter of the corresponding frame to the ad-hoc signal of the corresponding frame, and outputs the inverse filter;
• and
• a control step wherein a control means iteratively executes said inverse filter application steps, said prediction error filter calculation steps and said inverse filter calculation steps until said iteration termination condition is met.