# US 12,007,521 B2 · Detection method of a user of an apparatus for controlling one or more functionalities of the apparatus

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- Number: US 12,007,521 B2
- Document ID: US12007521B2
- Status: Granted
- Kind: B2
- Application number: 17/867,175
- Filed: 2022-07-18
- Published: 2023-01-26
- Granted: 2024-06-11
- Earliest claimed: 2021-07-26
- Assignees: STMicroelectronics S.r.l.
- Applicants: STMicroelectronics S.r.l.
- Inventors: Federico Rizzardini; Lorenzo Bracco
- Web page: https://patentgrep.com/patent/US12007521B2

## CPC

- G01S 17/04: Systems determining the presence of a target
- G01V 3/088: {operating with electric fields (G01V3/082 takes precedence)}
- H02J 50/20: using microwaves or radio frequency waves
- G01S 17/86: Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
- G05B 2219/34456: Authorize control of machine, robot if control panel has been connected
- 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
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

A detection method of a user of an apparatus is provided in which the apparatus is coupled to a charge variation sensor having a control unit and an electrode to detect an electric/electrostatic charge variation of the user. The detection method includes acquiring, through the electrode, a charge variation signal indicative of the presence of the user. A filtered signal is generated by filtering the charge variation signal. A feature signal is generated as a function of the filtered signal. A movement signal indicative of a movement of the user is generated as a function of the feature signal. A presence signal indicative of the presence of the user is generated as a function of the movement signal.

## Claims

### Claim 1

A detection method of a user of an apparatus operatively coupled to a charge variation sensor having at least one electrode and a control unit electrically coupled to each other, the at least one electrode being configured to detect a respective electric or electrostatic charge variation caused by the presence of the user in a detection region of the at least one electrode,
the detection method comprising:
acquiring, by the control unit and through the at least one electrode, a charge variation signal indicative of the presence or absence of the user in the detection region;
generating, by the control unit and as a function of the charge variation signal, one or more feature signals indicative of respective features of the charge variation signal;
generating, by the control unit and as a function of the one or more feature signals, a movement signal which has a value equal to a first value or to a second value, the first value of the movement signal being indicative of the absence of movement by the user in the detection region and the second value of the movement signal being indicative of a movement of the user in the detection region; and
generating, by the control unit and as a function of the movement signal, a presence signal which has a value equal to a first value or to a second value, the first value of the presence signal being indicative of the absence of the user from the detection region and the second value of the presence signal being indicative of the presence of the user in the detection region.

### Claim 2 (depends on 1)

The detection method according to claim 1, wherein the movement signal has, at each instant, a value equal to the first value or to the second value, the first value of the movement signal being indicative of the absence of movement at said instant, by the user in the detection region and the second value of the movement signal being indicative of the movement at said instant of the user in the detection region, and
wherein the presence signal has, at each instant, a value equal to the first value or to the second value, the first value of the presence signal being indicative of the absence at said instant of the user from the detection region and the second value of the presence signal being indicative of the presence at said instant of the user in the detection region.

### Claim 3 (depends on 1)

The detection method according to claim 1, wherein the generating the one or more feature signals comprises:
generating, by the control unit, a filtered signal by filtering the charge variation signal; and
generating, by the control unit, the one or more feature signals as a function of the filtered signal.

### Claim 4 (depends on 3)

The detection method according to claim 3, wherein the generating the one or more feature signals comprises calculating a peak-to-peak amplitude of the filtered signal or a variance of the filtered signal.

### Claim 5 (depends on 1)

The detection method according to claim 1, wherein the generating the movement signal comprises processing the one or more feature signals through machine learning techniques.

### Claim 6 (depends on 1)

The detection method according to claim 1, wherein the generating the movement signal comprises comparing the one or more feature signals with one or more respective feature threshold values, and determining the movement signal as a function of said comparison with the one or more feature threshold values.

### Claim 7 (depends on 6)

The detection method according to claim 6, wherein the generating the one or more feature signals comprises calculating said peak-to-peak amplitude of the filtered signal,
wherein the comparing the one or more feature signals with the one or more feature threshold values comprises comparing the respective value of the feature signal indicative of the peak-to-peak amplitude with a threshold peak-to-peak amplitude, and
wherein the determining the movement signal as a function of said comparison with the one or more feature threshold values comprises: setting the value at each instant of the movement signal equal to the first value when the respective value of the feature signal at said instant is lower than, or equal to, the threshold peak-to-peak amplitude; or setting the value at each instant of the movement signal equal to the second value when the respective value of the feature signal at said instant is greater than the threshold peak-to-peak amplitude.

### Claim 8 (depends on 1)

The detection method according to claim 1, wherein the generating the presence signal comprises setting the presence signal to the first value until the movement signal assumes the second value and, subsequently:
setting the presence signal to the second value whenever the movement signal assumes the second value or when a detection interval has elapsed from when the movement signal has switched from the first value to the second value, the movement signal having the second value in said detection interval;
setting the presence signal to the second value when the movement signal assumes the first value and a wait interval has not yet elapsed from the last instant in which the movement signal has assumed the second value; and
after said wait interval has elapsed from the last instant in which the movement signal has assumed the second value, setting the presence signal to the first value.

### Claim 9 (depends on 3)

The detection method according to claim 3, wherein the generating the filtered signal comprises filtering the charge variation signal through a low-pass filter having a cut-off frequency lower than a threshold cut-off frequency comprised between 1 Hz and 20 Hz.

### Claim 10 (depends on 1)

A control method of an apparatus for activating one or more functionalities of the apparatus,
the apparatus being usable by a user and including a main control unit operatively coupled to a charge variation sensor having at least one electrode and a control unit electrically coupled to each other, the at least one electrode being configured to detect a respective electric or electrostatic charge variation caused by the presence of the user in a detection region of the at least one electrode,
the control method comprising the steps of:
performing a detection method according to claim 1;
receiving, by the main control unit, the movement signal or the presence signal; and
controlling, by the main control unit, said one or more functionalities of the apparatus as a function of the movement signal or of the presence signal.

### Claim 11 (depends on 10)

The control method according to claim 10, wherein the main control unit is further operatively coupled to a proximity sensor configured to detect, when the user is in a field of view of the proximity sensor, a distance of the user from the proximity sensor, and
wherein the step of controlling said one or more functionalities of the apparatus comprises activating the proximity sensor as a function of the movement signal and/or of the presence signal.

### Claim 12 (depends on 1)

A computer program product loadable into a control unit of a charge variation sensor which is operatively coupled to an apparatus usable by a user and which includes at least one electrode electrically coupled to the control unit and configured to detect a respective electric or electrostatic charge variation caused by the presence of the user in a detection region of the at least one electrode,
said computer program configured to, when executed, cause the control unit to implement a detection method of the user according to claim 1.

### Claim 13

A charge variation sensor operatively couplable to an apparatus usable by a user, comprising:
at least one electrode configured to detect a respective electric or electrostatic charge variation caused by the presence of the user in a detection region of the at least one electrode; and
a control unit electrically couple to the at least one electrode, the control unit being configured to:
acquire, through the at least one electrode, a charge variation signal indicative of the presence or absence of the user in the detection region;
generate, as a function of the charge variation signal, one or more feature signals indicative of respective features of the charge variation signal;
generate, as a function of the one or more feature signals, a movement signal which has a value equal to a first value or to a second value, the first value of the movement signal being indicative of the absence of movement by the user in the detection region and the second value of the movement signal being indicative of a movement of the user in the detection region; and
generate, as a function of the movement signal, a presence signal which has a value equal to a first value or to a second value, the first value of the presence signal being indicative of the absence of the user from the detection region and the second value of the presence signal being indicative of the presence of the user in the detection region.

### Claim 14 (depends on 13)

The charge variation sensor according to claim 13, comprising a plurality of electrodes, each electrode being configured to detect the respective electric or electrostatic charge variation caused by the presence of the user in the respective detection region of said electrode, and to generate respective detection signals indicative of the respective detected electric and/or electrostatic charge variations,
wherein the charge variation signal is generated as a function of said detection signals.

### Claim 15 (depends on 13)

The charge variation sensor according to claim 13, wherein the control unit is configured to generate the one or more feature signals by:
generating, by the control unit, a filtered signal by filtering the charge variation signal; and
generating, by the control unit, the one or more feature signals as a function of the filtered signal.

### Claim 16 (depends on 15)

The charge variation sensor according to claim 15, wherein the control unit is configured to generate the one or more feature signals by calculating a peak-to-peak amplitude of the filtered signal or a variance of the filtered signal.

### Claim 17

An apparatus usable by a user and operatively coupled to a charge variation sensor having at least one electrode and a control unit electrically coupled to each other, the at least one electrode being configured to detect a respective electric or electrostatic charge variation caused by the presence of the user in a detection region of the at least one electrode, the control unit being configured to:
acquire, through the at least one electrode, a charge variation signal indicative of the presence or absence of the user in the detection region;
generate, as a function of the charge variation signal, one or more feature signals indicative of respective features of the charge variation signal;
generate, as a function of the one or more feature signals, a movement signal which has a value equal to a first value or to a second value, the first value of the movement signal being indicative of the absence of movement by the user in the detection region and the second value of the movement signal being indicative of a movement of the user in the detection region; and
generate, as a function of the movement signal, a presence signal which has a value equal to a first value or to a second value, the first value of the presence signal being indicative of the absence of the user from the detection region and the second value of the presence signal being indicative of the presence of the user in the detection region.

### Claim 18 (depends on 17)

The apparatus according to claim 17, wherein the control unit is configured to generate the one or more feature signals by:
generating, by the control unit, a filtered signal by filtering the charge variation signal; and
generating, by the control unit, the one or more feature signals as a function of the filtered signal.

### Claim 19 (depends on 18)

The apparatus according to claim 18, wherein the control unit is configured to generate the one or more feature signals by calculating a peak-to-peak amplitude of the filtered signal or a variance of the filtered signal.

### Claim 20 (depends on 18)

The apparatus according to claim 18, wherein the control unit is configured to generate the filtered signal by filtering the charge variation signal through a low-pass filter having a cut-off frequency lower than a threshold cut-off frequency comprised between 1 Hz and 20 Hz.