Patent No. 5136242 Method for measuring the field pattern of electrical or magnetic fields emanating from a biological power source using a sensor arrangement for obtaining chronological map of the position of the biological power source
Patent No. 5136242
Method for measuring the field pattern of electrical or magnetic fields emanating from a biological power source using a sensor arrangement for obtaining chronological map of the position of the biological power source (Abraham-Fuchs, Aug 4, 1992)
Abstract
A method for measuring the field pattern of electrical or magnetic fields using a sensor arrangement, for determining the spatial position of a biological power source is disclosed which compensates for background activity. The method includes the steps of measuring the background activity at a time before the biological power source is stimulated, and the resultant signal vector of the background activity is formed. This signal vector of the background activity is vectorially subtracted from each resultant vector of the subsequently obtained values from the biological power source, so that a signal vector is obtained which is essentially caused only by the current from the power source. A weighting factor, which varies the length of the vector of the background field, is iteratively calculated together with the source parameters for the biological power source by error minimization, so that the parameters of the power source can be optimally portrayed.
Notes:
SUMMARY
OF THE INVENTION
It is an object of the present invention to provide a method for measuring weak
magnetic fields of the type described above wherein the background activity
can be identified with sufficient precision to be able to be subtracted from
the measured signals, so that only signals identifying the biological power
source in question remain.
The above object is achieved in a method wherein the field pattern of background
activity having a physiological of technical origin can be defined at a specific
time before the stimulation of the biological activity to be measured. The amplitude
curve of the background activity is then constructed and is taken into consideration
during the duration of the measuring period by subtracting it from the overall
measured quantity, with the background activity having its proper amplitude
at each measuring time. This is accomplished by allocating a weighting factor
to the vector of the background field, so that the amplitude fluctuation thereof
dependent on the time can be identified for each individual measuring time.
This method results in the field difference between the measuring field and
the field emanating from the power source to be accurately identified, and therefore
the pattern of the field itself can be optimally identified.
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Although
modifications and changes may be suggested by those skilled in the art, it is
the intention of the inventor to embody within the patent warranted hereon all
changes and modifications as reasonably and properly come within the scope of
his contribution to the art.
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