MOTION ROBUST VITAL SIGNAL MONITORING

• US 20150250425A1
• Filed: 09/19/2013
• Published: 09/10/2015
• Est. Priority Date: 09/21/2012
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Shan, Caifeng
• Application Number:
  US14/428,006
• Publication Number:
  US 20150250425A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0431 Portable apparatus, e.g. comprising a handle or case
• CPC Class Codes: A61B 2560/0487 Special user inputs or interfaces
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/00 Measuring for diagnostic purposes radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00; Identification of persons
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/1128 using image analysis A61B5/1127 takes precedence
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30004 Biomedical image processing
• CPC Class Codes: G06T 2207/30076 Plethysmography
• CPC Class Codes: G06T 2207/30104 Vascular flow; Blood flow; Perfusion
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06T 7/248 involving reference images or patches
• CPC Class Codes: G06T 7/254 : involving subtraction of images

Abstract

The present invention relates to a device and a method for extracting physiological information from remotely detected electromagnetic radiation emitted or reflected by a subject (10). A data stream (30) derivable from electromagnetic radiation (20) emitted or reflected by a subject (10) is received. The data stream (30) comprises a sequence (76, 152) of signal samples (78a, 78b, 78c) including physiological information and indicative of disturbing motion. The signal samples (78a, 78b, 78c) represent at least one region of interest (68) exhibiting an at least partially periodic indicative pattern attributable to at least one physiological parameter (56), and a non-indicative motion region (110). The sequence (76, 152) of signal samples (78a, 78b, 78c) is processed, comprising deriving a sequence (106, 158) of derivative motion compensated samples (108a, 108b, 108c) at least partially compensated for undesired overall motion; detecting an evaluation parameter representative of motion compensation accuracy; and deriving at least one characteristic signal (128, 172, 176) at least partially indicative of the at least partially periodic indicative pattern from the sequence (106, 158) of motion compensated samples (108a, 108b, 108c), wherein deriving the characteristic signal (128, 172, 176) is performed depending on the detected evaluation parameter.

Claims

1. A device for extracting physiological information from remotely detected electromagnetic radiation emitted or reflected by a subject, comprising:

an interface for receiving a data stream derivable from electromagnetic radiation emitted or reflected by a subject, the data stream comprising a sequence of signal samples including physiological information and indicative of disturbing motion, the signal samples representing at least one region of interest-exhibiting an at least partially periodic indicative pattern attributable to at least one physiological parameter, and a non-indicative motion region; and

a processing unit configured for processing the sequence of signal samples, comprising;

a stabilizing means configured for deriving a sequence of derivative motion compensated samples at least partially compensated for undesired overall motion;

a motion compensation assessment means configured for detecting an evaluation parameter representative of motion compensation accuracy; and

an extractor means configured for selectively deriving at least one characteristic signal at least partially indicative of the at least partially periodic indicative pattern from the sequence of motion compensated samples, wherein deriving the characteristic signal is performed depending on the detected evaluation parameter.

2. A device as claimed in claim 1, wherein the signal samples are indicative of desired subject motion and of disturbing motion, the signal samples representing at least one region of interest exhibiting an at least partially periodic indicative motion pattern, the characteristic signal being at least partially indicative of the at least partially periodic indicative motion pattern.

3. A device as claimed in claim 1, wherein the processing unit further comprises an analyzing means configured for determining temporal variations in the characteristic signal, the temporal variations being representative of at least one vital signal.

4. A device as claimed in claim 1, wherein the evaluation parameter is a flag parameter representative of a state of a set of states indicative of motion compensation accuracy for a given motion compensated sample, or a given set of motion compensated samples.

5. A device as claimed in claim 1, wherein the extractor means, on the basis of the actual evaluation parameter, selectively performs or omits processing the respective motion compensated samples for deriving the at least one characteristic signal.

6. A device as claimed in claim 1, wherein the stabilizing means is configured for deriving the sequence of derivative motion compensated samples under consideration of at least one portion of the non-indicative motion region in the signal samples.

7. A device as claimed in claim 6, wherein the stabilizing means is further configured for detecting and tracking local features in the least one portion of the non-indicative motion region in the signal samples of the sequence.

8. A device as claimed in claim 1, wherein the motion compensation assessment means is configured for detecting a similarity between motion compensated samples under consideration of at least one portion of the non-indicative motion region in the motion compensated samples.

9. A device as claimed in claim 8, wherein the motion compensation assessment means is further configured for applying an absolute difference processing algorithm to the at least one portion of the non-indicative motion region in a respective motion compensated sample with respect to a reference sample.

10. A device as claimed in claim 1, wherein the motion compensation assessment means is configured for detecting feature correspondences in at least one portion of the non-indicative motion region in a respective motion compensated sample and in a reference sample, or wherein the motion compensation assessment means is further configured for detecting the evaluation parameter under consideration of a plurality of motion compensation assessment indicators.

11. A device as claimed in claim 1, further comprising a signal generation unit configured for generating a noticeable output signal depending on the actual evaluation parameter, wherein the output signal preferably indicates a state of a set of states indicative of motion compensation accuracy.

12. A device as claimed in claim 1, further comprising a sensor means, particularly a hand-held sensor means, configured for capturing electromagnetic radiation within at least one particular wavelength range selected from the group consisting of visible light, infrared light, and ultraviolet radiation, the sensor means being connectable to the interface.

13. A method for extracting physiological information from remotely detected electromagnetic radiation emitted or reflected by a subject, comprising:

receiving a data stream derivable from electromagnetic radiation emitted or reflected by a subject, the data stream comprising a sequence of signal samples comprising physiological information and indicative of disturbing motion, the signal samples representing at least one region of interest exhibiting an at least partially periodic indicative pattern attributable to at least one physiological parameter, and a non-indicative motion region; and

processing the sequence of signal samples, comprising;

deriving a sequence of derivative motion compensated samples at least partially compensated for undesired overall motion;

detecting an evaluation parameter representative of motion compensation accuracy; and

deriving at least one characteristic signal at least partially indicative of the at least partially periodic indicative pattern from the sequence of motion compensated samples, wherein deriving the characteristic signal is performed depending on the detected evaluation parameter.

14. A method as claimed in claim 13, wherein the signal samples are indicative of desired subject motion and of disturbing motion, the signal samples representing at least one region of interest exhibiting an at least partially periodic indicative motion pattern, the characteristic signal being at least partially indicative of the at least partially periodic indicative motion pattern.

15. A method as claimed in claim 13, further comprising the steps of:

on the basis of the actual evaluation parameter, selectively performing or omitting processing the respective motion compensated samples for deriving the at least one characteristic signal; and

determining temporal variations in the characteristic signal, the temporal variations being representative of at least one vital signal.