RESPIRATORY MOTION DETECTION APPARATUS

• US 20130035599A1
• Filed: 04/13/2011
• Published: 02/07/2013
• Est. Priority Date: 04/21/2010
• 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: De Bruijn, Frederik Jan, Vlutters, Ruud, Heinrich, Adrienne
• Granted Patent: US 11,471,073 B2
• Time in Patent Office: Days
• US Class Current: 600/476
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30004 Biomedical image processing
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

The invention relates to a respiratory motion detection apparatus (1) for detecting respiratory motion of a person. An illuminator (3) illuminates the person (2) with an illumination pattern (11), and a detector (4) detects the illumination pattern (11) on the person (2) over time. A temporal respiratory motion signal being indicative of the respiratory motion of the person (2) is determined from the detected illumination pattern by a respiratory motion signal determination unit (5). The illumination pattern deforms significantly with slight movements of the person. Thus, since the respiratory motion signal determination unit (5) is adapted to determine the temporal respiratory motion signal from the detected illumination pattern, even slight respiratory movements of the person can be determined. The sensitivity of detecting respiratory movements of a person can therefore be improved.

Claims

1. A respiratory motion detection apparatus for detecting respiratory motion of a person, the respiratory motion detection apparatus (1) comprising:

an illuminator for illuminating the person with at least one of a sinusoidal illumination pattern and a saw-tooth illumination pattern,

a detector for detecting the illumination pattern on the person over time,

a respiratory motion signal determination unit for determining a temporal respiratory motion signal being indicative of the respiratory motion of the person from the detected illumination pattern.

2. The respiratory motion detection apparatus as defined in claim 1, wherein the illuminator is adapted to illuminate the person in an illumination direction and the detector is adapted to detect the illumination pattern on the person in a detection direction, wherein the illumination direction and the detection direction are different.

3. The respiratory motion detection apparatus as defined in claim 2, wherein the illuminator and the detector are adapted to allow

the illuminator to illuminate a surface of the person with the illumination pattern under an illumination angle being defined as the angle between the illumination direction and an axis being perpendicular to the illuminated surface, and

the detector to detect the illumination pattern on the surface under a detection angle being defined as the angle between the detection direction and an axis being perpendicular to the illuminated surface,

wherein the illumination angle is larger than the detection angle.

4. The respiratory motion detection apparatus as defined in claim 1, wherein the detector is adapted to detect several images of the illumination pattern at different times, wherein the respiratory motion signal determination unit is adapted to determine the temporal respiratory motion signal depending on the sum of the absolute differences of image values of corresponding positions in temporally consecutive images.

5. The respiratory motion detection apparatus as defined in claim 1, wherein the respiratory motion detection apparatus further comprises a respiratory characteristics determination unit for determining a respiratory characteristic of the person from the determined temporal respiratory motion signal.

6. The respiratory motion detection apparatus as defined in claim 5, wherein the respiratory characteristics determination unit is adapted to determine inhale/exhale transitions and exhale/inhale transitions depending on the times at which the respiratory motion signal shows a local minimum.

7. The respiratory motion detection apparatus as defined in claim 5, wherein the respiratory characteristics determination unit is adapted to determine the inhale/exhale transitions depending on high-frequent local minima and to determine the exhale/inhale transitions depending on low-frequent local minima.

8. The respiratory motion detection apparatus as defined in claim 7, wherein the respiratory characteristics determination unit is adapted to

low-pass filter the respiratory motion signal such that the high-frequent minima are filtered out,

determine the local minima of the low-pass filtered respiratory motion signal,

determine the exhale/inhale transitions from the determined local minima.

9. The respiratory motion detection apparatus as defined in claim 7, wherein the respiratory characteristics determination unit is adapted to

calculate a streaming standard deviation of the respiratory motion signal,

determine local maxima of the calculated streaming standard deviation,

determine peak positions of peaks of the calculated streaming standard deviation having an amplitude larger than a predefined threshold,

determine for each local maximum of the local maxima a peak position among the determined peak positions, which is closest to the position of the respective local maximum, and

determine the inhale/exhale transitions from the determined peak positions.

10. The respiratory motion detection apparatus as defined in claim 9, wherein the respiratory characteristics determination unit is further adapted to weight the calculated streaming standard deviation before determining the positions of peaks, wherein the weight for a calculated streaming standard deviation value is larger, if the corresponding respiratory motion signal value is located in a local minimum or valley of the respiratory motion signal, and wherein the weight for a calculated streaming standard deviation value is smaller, if the corresponding respiratory motion signal value is not located in a local minimum or valley of the respiratory motion signal.

12. The respiratory motion detection apparatus as defined in claim 1, wherein the illuminator is adapted to illuminate the person with a spatially high-frequent illumination pattern.

13. The respiratory motion detection apparatus as defined in claim 1, wherein the respiratory motion detection apparatus is adapted to detect the respiratory motion of several persons, wherein

the illuminator is adapted to illuminate the several persons by the illumination pattern, and

the respiratory motion signal determination unit is adapted to assign different regions of the detected illumination pattern to the several persons and to determine the respiratory motion of a person of the several persons from the region of the detected illumination pattern assigned to the respective person.

15. A respiratory motion detection computer program for detecting respiratory motion of a person, the computer program comprising program code means for causing a respiratory motion detection apparatus as defined in claim 1 to carry out the steps of the respiratory motion detection method, when the computer program is run on a computer controlling the respiratory motion detection apparatus.

11. (canceled)

14. A respiratory motion detection method for detecting respiratory motion of a person, the respiratory motion detection method comprising:

illuminating the person with an illumination pattern,

detecting the illumination pattern on the person over time,

determining a respiratory motion signal being indicative of the respiratory motion of the person from the detected illumination pattern.