Distortion reduced signal detection

Abstract

A device and a method for extracting information from detected characteristic signals receives a data stream derivable from electromagnetic radiation emitted or reflected by an object. The data stream comprises a continuous or discrete characteristic signal including physiological information and a disturbing signal portion. The physiological information is representative of at least one at least partially periodic vital signal. The disturbing signal portion is representative of at least one of an object motion portion and/or a non-indicative reflection portion. The characteristic signal is transferred by converting at least three absolute components of the characteristic signal related to respective additive channels to at least two difference components of the characteristic signal, wherein each of the at least two difference components can be derived through a respective arithmetic transformation considering at least two of the at least three absolute components, wherein the arithmetic transformation for each of the at least two difference components further comprises coefficients that substantially sum to zero. Consequently, the disturbing signal portion can be at least partially suppressed in the transferred signal.

1 . Device for extracting information from detected characteristic signals, comprising:
 an interface for receiving a data stream derivable from electromagnetic radiation reflected by an object, wherein the data stream comprises a characteristic signal including (i) physiological information and (ii) a disturbing signal portion, the physiological information being representative of at least one at least partially periodic vital signal, the disturbing signal portion being representative of at least one selected from the group consisting of an object motion portion and a non-indicative reflection portion, wherein the characteristic signal is associated with an additive signal space, wherein the signal space comprises additive channels for representing the characteristic signal;   a converter means for transferring the characteristic signal into a transferred signal by converting (i) at least three absolute components of the characteristic signal related to respective additive channels to (ii) at least two difference components of the characteristic signal, wherein each of the at least two difference components is derived through a respective arithmetic transformation that comprises an at least partial subtraction of at least one of the at least three absolute components from the remaining absolute components, wherein the arithmetic transformation for each of the at least two difference components further comprises coefficients that substantially sum to zero, and further wherein the at least two difference components enable the disturbing signal portion to be at least partially suppressed in the transferred signal; and   an extractor means for extracting the at least partially periodic vital signal from the at least two difference components in the transferred signal.   
     
     
         2 . Device as claimed in  claim 1 , wherein the signal space is an additive color signal space, wherein the at least three absolute components represent three distinct color components indicated by the additive channels, wherein the additive channels are related to defined spectral portions. 
     
     
         3 . Device of  claim 2 , wherein the signal space is further indicative of luminance information and chrominance information, the chrominance information being representable by the at least two difference components. 
     
     
         4 . Device of  claim 3 , wherein the luminance information is substantially aligned with a luminance index element in the signal space, the luminance index element being substantially indicative of a selected source of electromagnetic radiation. 
     
     
         5 . Device of  claim 4 , wherein the at least two difference components are substantially orthogonal to the luminance index element. 
     
     
         6 . Device as claimed in  claim 1 , wherein the at least one at least partially periodic vital signal is selected from the group consisting of heart rate, heart beat, respiration rate, heart rate variability, Traube-Hering-Mayer waves, and oxygen saturation. 
     
     
         7 . Device of  claim 1 , further comprising a weighting means for weighting the at least two difference components so as to derive a weighted transferred signal from the transferred signal under consideration of at least two weighted difference components. 
     
     
         8 . Device of  claim 7 , wherein the weighting comprises a determination of a deviation value of each of the at least two difference components, and wherein the deviation value of each of the at least two difference components is determined under consideration of temporal variations thereof over a moving window applied to a sequence of each of the at least two difference components. 
     
     
         9 . Device of  claim 1 , wherein at least one of the converter means and the extractor means is further adapted to normalize the transferred signal under consideration of a deviation value thereof over a moving window applied to a sequence of the transferred signal. 
     
     
         10 . Device as claimed in  claim 1 , further comprising an analyzing means, the analyzing means being comprised in the extractor means or coupled thereto, wherein the analyzing means is adapted for a frequency analysis of the at least one at least partially periodic vital signal. 
     
     
         11 . Device as claimed in  claim 10 , further comprising a processing unit that comprises the converter means, the extractor means and the analyzing means. 
     
     
         12 . Device as claimed in  claim 11 , wherein at least one of the converter means, the extractor means and the analyzing means is further adapted for delivering a compressed output signal, wherein the compressed output signal comprises the luminance information represented by a luminance signal and the chrominance information represented by the at least two difference components, wherein selective compression rates are applied to the luminance information and the chrominance information, and wherein the chrominance information is compressed to a lower compression factor than the luminance information. 
     
     
         13 . Method for extracting information from detected characteristic signals, comprising the steps:
 receiving a data stream derivable from electromagnetic radiation reflected by an object, wherein the data stream comprises a characteristic signal including (i) physiological information and (ii) a disturbing signal portion, the physiological information being representative of at least one at least partially periodic vital signal, the disturbing signal portion being representative of at least one selected from the group consisting of an object motion portion and a non-indicative reflection portion, wherein the characteristic signal is associated with an additive signal space, wherein the signal space comprises additive channels for representing the characteristic signal;   transferring the characteristic signal into a transferred signal by converting (i) at least three absolute components of the characteristic signal related to respective additive channels to (ii) at least two difference components of the characteristic signal, wherein each of the at least two difference components is derived through a respective arithmetic transformation that comprises an at least partial subtraction of at least one of the at least three absolute components from the remaining absolute components, wherein the arithmetic transformation for each of the at least two difference components further comprises coefficients that substantially sum to zero, and further wherein the at least two difference components enable the disturbing signal portion to be at least partially suppressed in the transferred signal; and   extracting the at least partially periodic vital signal from the at least two difference components in the transferred signal.   
     
     
         14 . A non-transitory computer-readable medium embodied with a computer program comprising program code for causing a computer to carry out the steps of the method as claimed in  claim 13  when said computer program is carried out on the computer. 
     
     
         15 . Device of  claim 5 , further wherein the at least two difference components are substantially orthogonal to each other 
     
     
         16 . Device of  claim 7 , wherein the weighting is directed to minimize a spread of the weighted transferred signal. 
     
     
         17 . Device of  claim 8 , wherein the deviation value is a standard deviation. 
     
     
         18 . Device of  claim 9 , wherein the deviation value is a standard deviation. 
     
     
         19 . Device of  claim 10 , wherein the analyzing means is further adapted for filtering the processed transferred signal and for enhancing a signal component at a bandwidth between 0.2 Hz and 10 Hz. 
     
     
         20 . Device of  claim 19 , wherein the bandwidth further comprises between 0.5 Hz and 3.5 Hz.