# US 2010/0166252 A1 · Method and apparatus for determining blood oxygenation using a mobile communication device

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- Number: US 2010/0166252 A1
- Document ID: US20100166252A1
- Status: Published application
- Kind: A1
- Application number: 12/347,400
- Filed: 2008-12-31
- Published: 2010-07-01
- Earliest claimed: 2008-12-31
- Assignees: Motorola, Inc.
- Inventors: Imtiaz Ahmed AHMED; Jasmin Farshi; Krishna Jonnalagadda; Francesca Schuler
- Web page: https://patentgrep.com/patent/US20100166252A1

## CPC

- A61B 5/14551: {for measuring blood gases}
- A61B 5/6887: {mounted on external non-worn devices, e.g. non-medical devices}
- G06T 7/0014: {using an image reference approach}
- G06T 2207/10024: Color image
- G06T 2207/30088: Skin; Dermal
- G06T 2207/30104: Vascular flow; Blood flow; Perfusion
- G06V 40/14: Vascular patterns
- G06V 40/15: {Biometric patterns based on physiological signals, e.g. heartbeat, blood flow}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

A method (300) and apparatus (110) that determines blood oxygenation using a mobile communication device is disclosed. The method can include capturing (320) a plurality of images of skin using an array of pixels in a camera on a portable electronic device. The method can include comparing (330) image characteristics corresponding to the plurality of captured images at a first wavelength with image characteristics corresponding to the plurality of captured images at a second wavelength, the second wavelength being substantially distinct from the first wavelength. The method can include determining (340) blood oxygen level based on comparing the image characteristics.

## Claims

### Claim 1

A method comprising:
capturing a plurality of images of skin using an array of pixels in a camera on a portable electronic device;
comparing image characteristics corresponding to the plurality of captured images at a first wavelength with image characteristics corresponding to the plurality of captured images at a second wavelength, the second wavelength being substantially distinct from the first wavelength; and
determining blood oxygen level based on comparing the image characteristics.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising creating a plurality of binary images based on the plurality of captured images, where the plurality of binary images contain information corresponding to pixels exceeding a threshold,
wherein comparing image characteristics comprises comparing image characteristics corresponding to the plurality of binary images at the first wavelength with image characteristics corresponding to the plurality of binary images at the second wavelength.

### Claim 3 (depends on 1)

The method according to claim 1, wherein creating a plurality of binary images includes extracting raw Bayer images based on the plurality of captured images.

### Claim 4 (depends on 2)

The method according to claim 2, further comprising reducing dimensional content of the plurality of binary images to generate reduced dimension information,
wherein comparing image characteristics comprises comparing image characteristics corresponding to the reduced dimension information at the first wavelength with image characteristics corresponding to the reduced dimension information at the second wavelength.

### Claim 5 (depends on 4)

The method according to claim 4, wherein reducing the dimensional content of the plurality of binary images comprises summing a number of pixels exceeding the threshold for each image of the plurality of binary images to generate reduced dimension information.

### Claim 6 (depends on 4)

The method according to claim 4, further comprising filtering out low frequencies of the reduced dimension information to generate filtered reduced dimension information,
wherein comparing image characteristics comprises comparing image characteristics corresponding to the filtered reduced dimension information at the first wavelength with image characteristics corresponding to the filtered reduced dimension information at the second wavelength.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the blood oxygen level is based on:
(
log
10
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(
V
ac
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λ
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)
)
(
log
10
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V
ac
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λ
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)
where Vacλ1 corresponds to a pixel intensity value for the first wavelength obtained from the images from the camera, and
where Vacλ2 corresponds to a pixel intensity value for the second wavelength obtained from the images from the camera.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the blood oxygen level is based on:
α
r


2

R
-
α
r


1
(
α
r
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2
-
α
o
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
R
-
(
α
r


1
-
α
o
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
1
)
where αo1 is an absorption coefficient of oxygenated blood for the first wavelength,
where αo2 is an absorption coefficient of oxygenated blood for the second wavelength,
where αr1 is an absorption coefficient of deoxygenated blood for the first wavelength,
where αr2 is an absorption coefficient of deoxygenated blood for the second wavelength, and
where R is a ratio based on the absorbance of light at the first wavelength to the absorbance of light at the second wavelength.

### Claim 9 (depends on 8)

The method according to claim 8, where:
R
=
(
log
10

(
V
ac


λ


1
)
)
(
log
10

(
V
ac


λ


2
)
)
where Vacλ1 corresponds to a pixel intensity value for the first wavelength obtained from the images from the camera, and
where Vacλ2 corresponds to a pixel intensity value for the second wavelength obtained from the images from the camera.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the portable electronic device comprises a selective call receiver.

### Claim 11 (depends on 1)

The method according to claim 1, further comprising illuminating skin using a portable electronic device light emitting diode light source on the same side of the portable electronic device as the camera,
wherein capturing comprises capturing a plurality of images of the illuminated skin using an array of pixels in the camera on the portable electronic device.

### Claim 12 (depends on 1)

The method according to claim 1, wherein the camera comprises a complementary metal-oxide-semiconductor active pixel sensor digital imager camera.

### Claim 13 (depends on 1)

The method according to claim 1, wherein blood oxygen level is determined without using a dedicated infrared light source.

### Claim 14

An apparatus comprising:
a portable electronic device housing;
a selective call receiver transceiver coupled to the portable electronic device housing, the selective call receiver transceiver configured to engage in selective call receiver communications over a long distance wireless network;
a camera coupled to the portable electronic device housing, the camera including an array of pixels, the camera configured to capture a plurality of images of skin using the array of pixels;
a controller coupled to the camera, the controller configured to control operations of the apparatus; and
a blood oxygen level determination module coupled to the controller, the blood oxygen level determination module configured to determine blood oxygen level based on the plurality of captured images.

### Claim 15 (depends on 14)

The apparatus according to claim 14, further comprising an image comparison module coupled to the controller, the image comparison module configured to compare image characteristics corresponding to the plurality of captured images at a first wavelength with image characteristics corresponding to the plurality of captured images at a second wavelength, the second wavelength being substantially distinct from the first wavelength,
wherein the blood oxygen level determination module is configured to determine blood oxygen level based on the compared the image characteristics.

### Claim 16 (depends on 15)

The apparatus according to claim 15,
wherein the image comparison module is configured to create a plurality of binary images from the plurality of captured images, where the plurality of binary images contain information corresponding to pixels exceeding a threshold, and
wherein the image comparison module is configured to compare image characteristics by comparing image characteristics corresponding to the plurality of binary images at the first wavelength with image characteristics corresponding to the plurality of binary images at the second wavelength.

### Claim 17 (depends on 16)

The apparatus according to claim 16, wherein the image comparison module is configured to reduce dimensional content of the plurality of binary images by summing a number of pixels exceeding the threshold for each image of the plurality of binary images to generate reduced dimension information,
wherein the image comparison module is configured to compare image characteristics by comparing image characteristics corresponding to the reduced dimension information at the first wavelength with image characteristics corresponding to the reduced dimension information at the second wavelength.

### Claim 18 (depends on 14)

The apparatus according to claim 14, wherein the blood oxygen level is based on:
(
log
10

(
V
ac


λ


1
)
)
(
log
10

(
V
ac


λ


2
)
)
where Vacλ1 corresponds to a pixel intensity value for the first wavelength obtained from the images from the camera, and
where Vacλ2 corresponds to a pixel intensity value for the second wavelength obtained from the images from the camera.

### Claim 19 (depends on 14)

The apparatus according to claim 14, wherein the blood oxygen level is based on:
α
r


2

R
-
α
r


1
(
α
r


2
-
α
o


2
)

R
-
(
α
r


1
-
α
o


1
)
where αo1 is an absorption coefficient of oxygenated blood for the first wavelength,
where αo2 is an absorption coefficient of oxygenated blood for the second wavelength,
where αr1 is an absorption coefficient of deoxygenated blood for the first wavelength,
where αr2 is an absorption coefficient of deoxygenated blood for the second wavelength, and
where R is a ratio based on the absorbance of light at the first wavelength to the absorbance of light at the second wavelength.

### Claim 20

A method comprising:
capturing a plurality of images of skin using an array of pixels in a camera on a selective call receiver device, the selective call receiver device configured to engage in selective call receiver communications over a long distance wireless network;
creating a plurality of binary images from the plurality of captured images, where the plurality of binary images contain information corresponding to pixels of the plurality of captured images exceeding a threshold;
comparing image characteristics corresponding to the plurality of binary images at the first wavelength with image characteristics corresponding to the plurality of binary images at the second wavelength, the second wavelength being substantially distinct from the first wavelength; and
determining blood oxygen level based on comparing the image characteristics.