Signal separation method, signal processing apparatus, image processing apparatus, medical image processing apparatus and storage medium for restoring multidimensional signals from observed data in which multiple signals are mixed

A signal separation method for estimating and restoring original multidimensional signals from observed data where multiple signals including the original multidimensional signals are mixed, the method comprising the steps of:

• introducing a cost function for the observed data, the cost function being based on a function that has a monotonously increasing characteristic;
• estimating a separation matrix using an adaptive filter that optimizes the introduced cost function;
• and
• multiplying the observed data by the estimated separation matrix to estimate and restore the original multidimensional signals.

A method for separating and extracting original signals from observed signals where multiple multidimensional signals including the original signals are mixed, the method comprising the steps of:

• reading the observed signals;
• transforming a data structure in terms of the read observed signals;
• subtracting an average of the observed signals from each of the observed signals, which data structure has been transformed to perform zero averaging;
• performing whitening on the observed signals that have undergone zero averaging;
• performing separation processing on the observed signals that have undergone whitening based on a cost function having a monotonously increasing characteristic;
• and
• performing inverse whitening as post-processing on the observed signals that have undergone the separation processing.

A signal processing apparatus, comprising:

• means for inputting observed data where multiple signals including original multidimensional signals are mixed;
• means for selecting a specific separation matrix by optimizing at least either one of H-infinity norm type of cost function or MinMax strategy type of cost function for the input observed data;
• and
• means for multiplying the observed data by the selected separation matrix to estimate and restore the original multidimensional signals.

A signal processing apparatus, comprising:

• means for inputting observed data where multiple multidimensional signals that are originally independent are mixed mutually;
• means for estimating a separation matrix by using an adaptive filter for the input observed data, the filter optimizing a cost function based on a function that has a monotonously increasing characteristic;
• and
• means for multiplying the observed data by the estimated separation matrix to estimate and restore the specific multidimensional signals.

An image processing apparatus, comprising:

• means for inputting mixed image data where multiple image signals are mixed and observed;
• means for estimating a separation matrix by using an adaptive filter for the input mixed image data, the filter optimizing a cost function based on a function having a monotonously increasing characteristic;
• and
• means for multiplying the mixed image data by the estimated separation matrix to separate and extract the image signals from the mixed image data.

A medical image processing apparatus, comprising:

• means for inputting medical image data where a signal change of which interference process is unknown is contained in observed bio-image signals;
• means for estimating a separation matrix by using an adaptive filter for the input medical image data, the filter optimizing a cost function based on a function having a monotonously increasing characteristic;
• and
• means for multiplying the medical image data by the estimated separation matrix to separate and extract the observed bio-image signals from the medical image data.

A storage medium tangibly embodying a program readable and executable by a computer, the program comprising:

• processing for introducing a cost function for observed data where multiple multidimensional signals are mixed, the cost function being based on a function that has a monotonously increasing characteristic;
• processing for estimating a separation matrix using an adaptive filter that optimizes the introduced cost function;
• and
• processing for multiplying the observed data by the estimated separation matrix to estimate and restore the specific multidimensional signals.