METHOD AND SYSTEM FOR OBTAINING A FIRST SIGNAL FOR ANALYSIS TO CHARACTERIZE AT LEAST ONE PERIODIC COMPONENT THEREOF

• US 20120195486A1
• Filed: 09/29/2010
• Published: 08/02/2012
• Est. Priority Date: 10/06/2009
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kirenko, Ihor Olehovych, Jeanne, Vincent, De Haan, Gerard, Van Leest, Adriaan Johan
• Granted Patent: US 8,666,116 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: G06T 2207/30076 Plethysmography
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 7/0012 Biomedical image inspection

Abstract

A method of facilitating obtaining a first signal (42;50a-n) for analysis to characterize at least one periodic component thereof, includes obtaining at least two second signals (18-20) representative of intensities of captured electromagnetic radiation, each corresponding to a respective different radiation frequency range. The first signal (42;50a-n) is at least derivable from an output signal (31) obtainable by applying a transformation (22,26,30) to the second signals (18-20;55-57) such that any value of the output signal (31) is based on values from each respective second signal (18-20;55-57) at corresponding points in time. The method further includes obtaining at least one value of at least one variable determining influences of at least components of respective second signals (18-20;55-57) on the output signal (31) when the signals corresponding to the second signals (18-20;55-57) are captured and the transformation (22,26,30) is applied, by at least one of: (i) analyzing at least one of the second signals (18-20;55-57), an output signal (31) obtained by applying the transformation (22,26,30) to the second signals (18-20) and a first signal (42;50a-n) derived from the output signal (31) and using the analysis to select at least one value of at least one parameter (54) corresponding to a respective one of the variables; and (ii) calculating values of at least one time-varying factor corresponding to a respective one of the variables, each factor value based on at least one second signal value, and applying each factor in an operation in at least one of a number of parallel sequences of operations comprising at least one such operation and taking a signal corresponding to a respective one of the second signals (55-57) as input.

Claims

1. Method of facilitating obtaining a first signal (42;

50a-n;

76) for analysis to characterize at least one periodic component thereof, including;

obtaining at least two second signals (18-20;

55-57) representative of intensities of captured electromagnetic radiation, each corresponding to a respective different radiation frequency range,

the first signal (42;

50a-n;

76) being at least derivable from an output signal (31;

72) obtainable by applying a transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) such that any value of the output signal (31;

72) is based on values from each respective second signal (18-20;

55-57) at corresponding points in time,

the method further including;

obtaining at least one value of at least one variable determining influences of at least components of respective second signals (18-20;

55-57) on the output signal (31;

72) when the signals corresponding to the second signals (18-20;

55-57) are captured and the transformation (22,26,30;

59,63,67,71) is applied, by at least one of;

(i) analyzing at least one of the second signals (18-20;

55-57), an output signal (31;

72) obtained by applying the transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) and a first signal (42;

50a-n;

76) derived from the output signal (31;

72) and using the analysis to select at least one value of at least one parameter (54) corresponding to a respective one of the variables; and

(ii) calculating values of at least one time-varying factor corresponding to a respective one of the variables, each factor value based on at least one second signal value, and applying each factor in an operation (59,63) in at least one of a number of parallel sequences of operations comprising at least one such operation and taking a signal corresponding to a respective one of the second signals (55-57) as input.

2. Method according to claim 1, wherein the analysis of at least one of the second signals (18-20;

55-57), an output signal (31;

72) obtained by applying the transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) and a first signal (42;

50a-n;

76) derived from the output signal (31;

72) is used to select at least one value (54) of at least one parameter determining influences of at least components of respective second signals (18-20;

55-57) on the output signal (31) so as to maximize a relative signal strength in a limited part of a spectrum of the first signal (42;

50a-n).

3. Method according to claim 1, wherein the transformation (22,26,30) includes at least one parameterized operation, and wherein the analysis of at least one of the second signals (18-20;

55-57), an output signal (31;

72) obtained by applying the transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) and a first signal (42;

50a-n;

76) derived from the output signal (31;

72) is used to select values of at least one parameter of the operation.

4. Method according to claim 3, wherein the operation (26) is an operation taking at least two inputs (23,24,25) based in different ways on the second signals (18-20).

5. Method according to claim 3, wherein the transformation includes an operation (22) carried out in parallel on respective input signals (18-20) using at least one parameter value specific to fewer than all of the input signals (18-20).

6. Method according to claim 3, wherein the transformation includes at least one parameterized non-linear operation (22,30), and wherein the analysis of at least one of the second signals (18-20;

55-57), an output signal (31;

72) obtained by applying the transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) and a first signal (42;

50a-n;

76) derived from the output signal (31;

72) is used to select values of at least one parameter of the operation.

7. Method according to claim 1, wherein the transformation includes an operation (22) carried out in parallel on respective input signals, each a different linear combination of second signals (18-20) with at least one coefficient differing from zero, the operation comprising taking a logarithm of the input signal.

8. Method according to claim 1, wherein the analysis includes carrying out a principal component analysis on data sets respectively based on a plurality of second signals (18-20).

9. Method according to claim 1, wherein at least one of the second signals (18-20;

55-57), an output signal (31;

72) obtained by applying the transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) and a first signal (42;

50a-n;

76) derived from the output signal (31;

72) is analyzed and the analysis is used to select at least one value of at least one parameter (54) determining influences of at least components or respective second signals (18-20;

55-57) on the output signal (31;

72) when the signals corresponding to the second signals are captured and the transformation (22,26,30;

59,63,67,71) is applied, the method further including causing the selected values of the at least one parameter (54) to be loaded into a system comprising;

an interface for obtaining at least two second signals (18-20;

55-57) representative of intensities of captured electromagnetic radiation, each corresponding to a respective different radiation frequency range; and

a signal processing system for applying a transformation to the second signals (18-20;

55-57) to obtain an output signal (31;

72) from which the first signal (42;

50a-n;

76) is at least derivable, any value of the output signal (31;

72) being based on values from each respective second signal (18-20;

55-57) at a common point in time, wherein the system is arranged to cause influences of respective second signals (18-20;

55-57) on the output signal (31;

72) to be determined at least partly in accordance with the loaded values (54) of the at least one parameter.

10. Method according to claim 1, wherein the analysis of at least one of the second signals (18-20;

55-57), an output signal (31;

72) obtained by applying the transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) and a first signal (42;

50a-n;

76) derived from the output signal (31;

72) and the selection of at least one parameter value (54) is carried out continually whilst processing the second signals (18-20) to obtain the first signal (42;

50a-n).

11. Method according to claim 1, wherein the at least one time-varying factor includes a factor obtainable by calculating a linear combination of corresponding values from each of at least one of the second signals (55-57), and wherein the same value of that factor is used in each of the parallel sequences of operations.

12. Method according to claim 1, wherein, for at least one of the factors, separate values at corresponding associated points in time are calculated for each of the parallel sequences, each obtained from multiple values of the second signal (55-57) taken as input by the sequence concerned, the multiple values being associated with respective points in time spanning an interval including the point in time associated with the factor value.

15. Computer program including a set of instructions capable, when incorporated in a machine-readable medium, of causing a system having information processing capabilities to perform a method according to claim 1.

13. System for obtaining a first signal (42;

50a-n;

76) for analysis to characterize at least one periodic component thereof, including;

an interface (8,12) for obtaining at least two second signals (18-20;

55-57) representative of intensities of captured electromagnetic radiation, each corresponding to a respective different radiation frequency range,

the first signal (42;

50a-n) being at least derivable from an output signal (31;

72) obtainable by applying a transformation (22,26,30;

59,63,67,71) to the second signals (18-20;

55-57) such that any value of the output signal (31;

72) is based on values from each respective second signal (18-20;

55-57) at corresponding points in time;

wherein the system is arranged to

obtain at least one value of at least one variable determining influences of at least components of respective second signals (18-20;

55-57) on the output signal (31;

72) when the signals corresponding to the second signals (18-20;

55-57) are captured and the transformation (22,26,30;

59,63,67,71) is applied, by at least one of;

(i) analyzing at least one of the second signals (18-20;

55-57), the output signal (31;

72) and the first signal (42;

50a-n;

76) and using the analysis to select at least one value (54) of at least one parameter corresponding to a respective one of the variables and determining influences of at least components of respective second signals (18-20;

55-57) on the output signal (31;

72) when signals corresponding to the second signals (18-20;

55-57) are captured and the transformation is applied; and

(ii) calculating values of at least one time-varying factor corresponding to a respective one of the variables, each factor value based on at least one second signal value, and applying each factor in an operation in at least one of a number of parallel sequences of operations comprising at least one such operation and taking a signal corresponding to a respective one of the second signals (55-57) as input.

14. (canceled)