# US 10,307,064 B2 · Method and device for locating at least one target in an electromagnetically absorbent environment

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- Number: US 10,307,064 B2
- Document ID: US10307064B2
- Status: Granted
- Kind: B2
- Application number: 14/888,611
- Filed: 2014-03-24
- Published: 2016-03-03
- Granted: 2019-06-04
- Earliest claimed: 2013-05-02
- Assignees: Centre National De La Recherche Scientifique; Ecole Centrale De Marseille; Universite D'Aix-Marseille
- Applicants: Centre National de la Recherche Scientifique; Ecole Centrale de Marseille; Universite d'Aix Marseille
- Inventors: Anabela Da Silva; Serge Mensah
- Web page: https://patentgrep.com/patent/US10307064B2

## CPC

- A61B 5/0095: {by applying light and detecting acoustic waves, i.e. photoacoustic measurements}
- A61B 5/0093: {Detecting, measuring or recording by applying one single type of energy and measuring its conversion into another type of energy}
- G01N 21/1702: {with opto-acoustic detection, e.g. for gases or analysing solids}
- A61B 5/0059: {using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455)}
- A61B 8/00: Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B 2576/00: Medical imaging apparatus involving image processing or analysis (A61B1/00009, A61B6/52 and A61B8/52 take precedence)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A method for locating at least one target, in an electromagnetically absorbent environment, includes: emitting at least one electromagnetic excitation signal from a source; receiving, by an acoustic sensor, an acoustic signal from emission of the excitation signal; detecting, in the received acoustic signal, a first time of receipt of a first response to the excitation signal from an acoustic disturbance caused by electromagnetic heterogeneity of the target in the environment; estimating a first distance between the target and the acoustic sensor using the first time of receipt; detecting, in the same received acoustic signal, a second time of receipt of a second response to the excitation signal from an acoustic disturbance caused by acoustic heterogeneity of the target in the environment; estimating a second distance between the source and target using the second time of receipt; obtaining a location of the target from the first and second estimated distances.

## Claims

### Claim 1

A method for locating at least one target in an electromagnetically absorbent environment, comprising:
emitting at least one electromagnetic excitation signal from at least one source;
receiving, by at least one acoustic sensor, an acoustic signal resulting from the emitting the excitation signal;
detecting, in the received acoustic signal by the acoustic sensor, a first time of receipt of a first response to the excitation signal, the first response resulting from an acoustic disturbance caused by an electromagnetic heterogeneity of the target in the environment;
estimating a first distance between the target and the acoustic sensor using the first time of receipt;
detecting, in the same received acoustic signal by the acoustic sensor, a second time of receipt of a second response to the excitation signal, this second response resulting from an acoustic disturbance caused by an acoustic heterogeneity of the target in the environment;
estimating a second distance between the source and the target using the second time of receipt; and
obtaining a location of the target from the first and second estimated distances.

### Claim 2 (depends on 1)

The method for locating at least one target according to claim 1, wherein:
the estimating of the first distance between the target and the acoustic sensor includes multiplying a first flight time of the first response between the target and the acoustic sensor by a predetermined value of acoustic wave speed in the environment;
the first flight time is estimated as elapsed time between a time of emission of the excitation signal and the first time of receipt.

### Claim 3 (depends on 2)

The method for locating at least one target according to claim 2, wherein:
the estimating of the second distance between the source and the target includes multiplying a second flight time of the second response between the source and the target by the predetermined value of the acoustic wave speed in the environment;
the second flight time is estimated as a difference between the elapsed time between time of emission of the excitation signal and the second time of receipt, and the first flight time.

### Claim 4 (depends on 1)

The method for locating at least one target according to claim 1, wherein the location of the target in three-dimensional space is obtained by intersection of first and second spheres, with the first sphere having as a center the acoustic sensor and as a radius the first distance, with the second sphere having the source as a center and the second distance as a radius.

### Claim 5 (depends on 1)

The method for locating at least one target according to claim 1, wherein the excitation signal emitted is an optical signal coming from a light source with a modulated frequency and/or intensity and the acoustic signal resulting from the excitation signal are pulse response resulting from two acoustic disturbances caused by a double optical and acoustic heterogeneity of the target in the environment.

### Claim 6 (depends on 1)

The method for locating at least one target according to claim 1, further comprising:
emitting electromagnetic excitation signals from plural sources distributed at a periphery of the environment wherein the target is located;
receiving, by plural acoustic sensors distributed at the periphery of the environment wherein the target is located, acoustic signals resulting from the emissions of the excitation signals; and
tomographic reconstruction of an image of the target in the environment wherein it is located, using obtained locations of the target.

### Claim 7 (depends on 6)

The method for locating at least one target according to claim 6, wherein the sources and the acoustic sensors are distributed regularly on a circle around the environment wherein the target is located.

### Claim 8 (depends on 1)

An application of a method for locating at least one target according to claim 1 for detecting and locating tumors in biological tissues.

### Claim 9 (depends on 1)

A non-transitory computer readable medium including computer executable instructions that can be read by a computer and/or that can be executed by a processor, comprising instructions for execution of the method for locating at least one target according to claim 1, when executed on a computer.

### Claim 10

A device for locating at least one target in an electromagnetically absorbent environment, comprising:
at least one source for emitting at least one electromagnetic excitation signal;
at least one acoustic sensor of an acoustic signal resulting from the emitting of the excitation signal;
a calculator configured to detect, in the received acoustic signal by the acoustic sensor, a first time of receipt of a first response to the excitation signal, the first response resulting from an acoustic disturbance caused by an electromagnetic heterogeneity of the target in the environment, and to estimate a first distance between the target and the acoustic sensor using this first time of receipt;
the calculator further configured to:
detect, in the same received acoustic signal by the acoustic sensor, a second time of receipt of a second response to the excitation signal, the second response resulting from an acoustic disturbance caused by an acoustic heterogeneity of the target in the environment;
estimate a second distance between the source and the target using the second time of receipt; and
provide a locating of the target from the first and second estimated distances.