PROCESSING IMAGES OF AT LEAST ONE LIVING BEING

• US 20110311119A1
• Filed: 03/01/2010
• Published: 12/22/2011
• Est. Priority Date: 03/06/2009
• 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: De Bruijn, Frederik Jan, Vlutters, Ruud, Chestakov, Dmitri, Jeanne, Vincent, Cennini, Giovanni
• Granted Patent: US 8,542,877 B2
• Time in Patent Office: Days
• US Class Current: 382/128
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0064 Body surface scanning
• CPC Class Codes: A61B 5/0255 Recording instruments specially adapted therefor
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: A61B 6/541 involving acquisition triggered by a physiological signal
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/30076 Plethysmography
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/90 Determination of colour characteristics

Abstract

A method of processing images of at least one living being, includes obtaining a sequence (19) of digital images taken at consecutive points in time. At least one measurement zone (26) comprising a plurality of image points is selected. For each measurement zone (26), a signal (28,30) representative of at least variations in a time-varying value of a combination of pixel values at least a number of the image points for use in determining at least one of a presence and a frequency value of at least one peak in a spectrum of the signal (28,30) corresponding to a frequency of a periodic physiological phenomenon is obtained. The step (25) of selecting at least one measurement zone (26) includes analyzing information based on pixel data of a plurality of image parts in at least one of the images (19), each image part including at least one image point, and selecting each measurement zone (26) from contiguous parts determined to have similar characteristics.

Claims

1. Method of processing images of at least one living being, including:

obtaining a sequence (19) of digital images taken at consecutive points in time;

selecting at least one measurement zone (26) comprising a plurality of image points, wherein

the step (25) of selecting at least one measurement zone (26) includes analyzing information based on pixel data of a plurality of image parts in at least one of the images (19), each image part including at least one image point, and selecting each measurement zone (26) from contiguous parts determined to have similar characteristics; and

for each measurement zone (26), obtaining a signal (28,30) representative of at least variations in a time-varying average value of a combination of pixel values at least a number of the image points for use in determining at least one of a presence and a frequency value of at least one peak in a spectrum of the signal (28,30) corresponding to a frequency of a periodic physiological phenomenon.

2. Method according to claim 1,

including performing image segmentation on at least one of the sequence (19) of digital images to select pixel data for the analysis included in the selection step (25).

3. Method according to claim 2,

wherein the image segmentation is performed using an algorithm for recognizing image parts (23) corresponding to at least one type of body part of a living being.

4. Method according to claim 1,

including using a tracking algorithm to place at least one of the measurement zone (26) and an image segment (23) including the measurement zone (26) in each of a plurality of the images in the sequence (19).

5. Method according to claim 1,

wherein the sequence (19) of digital images is caused to be captured by a camera (2;

41) upon completion of an initialization phase (17), the initialization phase (17) including;

measuring periodic intensity fluctuations in at least parts of images acquired by the camera (2;

41) whilst camera settings are varied, and

selecting values of the camera settings at which measured periodic intensity fluctuations in at least a range of frequencies are determined to be minimal.

6. Method according to claim 1, including:

determining a correction signal corresponding to a time-varying value of a combination of pixel values at least a number of image points in an image part other than the measurement zone (26), and

decorrelating at least one of the pixel data of the images in at least the measurement zone (26) and the time-varying average value of the combination of pixel values at least a number of the image points in the measurement zone (26) from the correction signal.

7. Method according to claim 1,

wherein an output representative of whether the presence of at least one peak in the spectrum corresponding to a frequency of the periodic physiological phenomenon is detected is used to control a device (8,9,13) arranged to perform a function conditional on detecting a presence of at least one living being of at least one kind.

8. Method according to claim 7,

wherein the output is provided to a conditional access system (3,13) for use in an authentication operation.

9. Method according to claim 1,

wherein the frequency value of at least one peak in the spectrum corresponding to the frequency of the periodic physiological phenomenon is determined and a system (9-12) for providing perceptible output is caused to adapt its output in dependence on the frequency signal.

10. Method according to claim 1,

including providing a gating signal based on the signal (28,30) corresponding to at least the variation in the time-varying average value of a combination of pixel values at least a number of the image points to an imaging system (32,34,35).

11. Method according to claim 1,

including:

selecting a plurality of measurement zones (26);

for each measurement zone (26), obtaining a signal representative of at least variations in a time-varying average value of a combination of pixel values at least a number of the image points and determining the frequency value of at least one peak in a spectrum of the signal corresponding to a frequency of a periodic physiological phenomenon; and

detecting how many living beings are represented in the sequence of images by comparing the frequency values.

13. System according to claim 12, configured to carry out a method according to any one of claims 1-11.

14. Computer programme 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.

12. System for processing images of at least one living being, including:

an interface (4;

42) for obtaining data representative of a sequence (19) of digital images taken at consecutive points in time; and

an image data processing system (3;

35), configured to;

select at least one measurement zone (26) comprising a plurality of image points, wherein the image data processing system (3;

35) is configured to select the at least one measurement zone (26) by analyzing information based on pixel data of a plurality of image parts in at least one of the images (19), each image part including at least one image point, and to select each measurement zone (26) from contiguous parts determined to have similar characteristics; and

for each measurement zone (26), to obtain a signal (28,30) representative of at least variations in a time-varying value of a combination of pixel values at least a number of the image points for use in determining at least one of a presence and a frequency value of at least one peak in a spectrum of the signal (28,30) corresponding to a frequency of a periodic physiological phenomenon.