# US 2021/0275035 A1 · Method, system, and computer program product for automatic multi-object localization and/or vital sign monitoring

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- Number: US 2021/0275035 A1
- Document ID: US20210275035A1
- Status: Published application
- Kind: A1
- Application number: 17/195,634
- Filed: 2021-03-08
- Published: 2021-09-09
- Earliest claimed: 2020-03-09
- Assignees: Stichting IMEC Nederland
- Applicants: Stichting IMEC Nederland
- Inventors: Yiting LU; Marco MERCURI
- Web page: https://patentgrep.com/patent/US20210275035A1

## CPC

- A61B 5/024: Measuring pulse rate or heart rate
- G01S 7/415: {Identification of targets based on measurements of movement associated with the target}
- A61B 5/0507: using microwaves or terahertz waves
- G01S 13/52: Discriminating between fixed and moving objects or between objects moving at different speeds
- G01S 13/536: using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves
- G16H 10/60: for patient-specific data, e.g. for electronic patient records
- G16H 40/60: for the operation of medical equipment or devices
- G16H 40/67: for remote operation
- G16H 50/30: for calculating health indices; for individual health risk assessment
- G06F 17/142: {Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A method for automatic multi-object localization and/or vital sign monitoring is provided. The method comprises the steps of receiving a radar signal in order to form a corresponding observation matrix, reducing noise by applying singular value decomposition to the observation matrix, processing the result of the singular value decomposition by an independent component analysis in order to estimate the corresponding sources, and estimating propagation channels of the estimated sources by minimizing the corresponding residual error based on the observation matrix and the estimated sources.

## Claims

### Claim 1

A method for automatic multi-object localization and/or vital sign monitoring, the method comprising the steps of:
transmitting a radar signal,
receiving a corresponding radar signal in order to form a corresponding observation matrix (X),
reducing noise by applying singular value decomposition to the observation matrix (X),
processing the result of the singular value decomposition by an independent component analysis in order to estimate the corresponding sources (Ŝ), and
estimating propagation channels (H) of the estimated sources (Ŝ) by minimizing the corresponding residual error (∥X−HŜ22) based on the observation matrix (X) and the estimated sources (Ŝ).

### Claim 2 (depends on 1)

The method according to claim 1,
wherein before the independent component analysis, the method further comprises the step of estimating the number of respective targets, preferably the number of respective persons, especially by calculating the signal-to-noise ratio of the respective uncorrelated sources in the result of the singular value decomposition.

### Claim 3 (depends on 1)

The method according to claim 1
wherein the method further comprises the step of locating the respective objects and/or removing the respective order ambiguity on the basis of the estimated propagation channels (Ĥ).

### Claim 4 (depends on 1)

The method according to claim 1,
wherein the method further comprises the step of performing a phase demodulation with respect to the estimated sources (Ŝ).

### Claim 5 (depends on 4)

The method according to claim 4,
wherein the method further comprises the step of extracting the respective vital sign information or signal (ŷ(t)) from the time domain signals (ŝ(t)) of the estimated sources (Ŝ) after the phase demodulation.

### Claim 6 (depends on 5)

The method according to claim 5,
wherein the step of extracting is performed on the basis of the following equation:
y
^
⁡
(
t
)
=
s
^
⁡
(
t
)
⁢
λ
0
4
⁢
π
,
wherein λ0 denotes the corresponding wavelength at the first frequency of a respective chirp signal, and
wherein π denotes the constant Pi.

### Claim 7 (depends on 5)

The method according to claim 5,
wherein the method further comprises the step of obtaining the corresponding respiration and heartbeat signals by performing a filtering operation with respect to the respective vital sign information or signal (ŷ(t)).

### Claim 8 (depends on 7)

The method according to the claim 7,
wherein the method further comprises the step of estimating the corresponding heart rates by performing a frequency transform with respect to the respective respiration and heartbeat signals.

### Claim 9 (depends on 8)

The method according to claim 8,
wherein the frequency transform comprises or is a fast Fourier transform.

### Claim 10 (depends on 5)

The method according to claim 5,
wherein the method further comprises the step of obtaining the corresponding respiration and heartbeat signals by performing a wavelet decomposition with respect to the respective vital sign information (ŷ(t)).

### Claim 11 (depends on 5)

The method according to claim 5,
wherein the method further comprises the step of obtaining the corresponding respiration and heartbeat signals by performing a Hilbert transform and/or further convex optimization steps with respect to the respective vital sign information or signal (ŷ(t)).

### Claim 12 (depends on 1)

The method according to claim 1,
wherein the radar signal comprises or is a chirp signal.

### Claim 13 (depends on 1)

The method according to claim 1,
wherein the radar signal originates from a frequency-modulated continuous wave radar, preferably a single input single output frequency-modulated continuous wave radar.

### Claim 14

A system for automatic multi-object localization and/or vital sign monitoring, the system comprising:
a transmitting unit, and
a receiving unit, and
a processing unit,
wherein the transmitting unit is configured to transmit a radar signal, the receiving unit is configured to receive a corresponding radar signal in order to form a corresponding observation matrix (X), and
wherein the processing unit (12) is configured to reduce noise by applying singular value decomposition to the observation matrix (X), to process the result of the singular value decomposition by an independent component analysis in order to estimate the corresponding sources (Ŝ), and to estimate propagation channels (H) of the estimated sources (Ŝ) by minimizing the corresponding residual error (∥X−HŜ∥22) based on the observation matrix (X) and the estimated sources (Ŝ).

### Claim 15 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)

A computer program product comprising computer program code means adapted for automatic multi-object localization and/or vital sign monitoring according to all steps of the method of any of the claims 1 to 13 when said program is run on a computer or any digital system.