# US 12,372,475 B2 · Optical sensing system and optical sensing method

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- Number: US 12,372,475 B2
- Document ID: US12372475B2
- Status: Granted
- Kind: B2
- Application number: 18/377,843
- Filed: 2023-10-09
- Published: 2025-04-10
- Granted: 2025-07-29
- Earliest claimed: 2023-10-09
- Assignees: Pixart Imaging Inc.
- Applicants: Pixart Imaging Inc.
- Inventors: Guo-Zhen Wang
- Web page: https://patentgrep.com/patent/US12372475B2

## CPC

- A47L 9/2826: {the condition of the floor}
- G01N 21/8806: {Specially adapted optical and illumination features}
- A47L 9/2847: {Surface treating elements}
- A47L 9/2852: {Elements for displacement of the vacuum cleaner or the accessories therefor, e.g. wheels, casters or nozzles}
- G01N 21/8851: {Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges (G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002)}
- A47L 2201/06: Control of the cleaning action for autonomous devices; Automatic detection of the surface condition before, during or after cleaning
- G01N 2021/8825: {Separate detection of dark field and bright field}
- A47L: DOMESTIC WASHING OR CLEANING (brushes A46B; cleaning quantities of bottles or of other hollow articles of one kind B08B9/00; laundry D06F); SUCTION CLEANERS IN GENERAL (cleaning in general B08)
- 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

An optical sensing system and an optical sensing method are provided. The system includes a bright-field light source, a dark-field light source, an optical detecting circuit, and a processing circuit. The processing circuit performs a floor type detection process, including: controlling the dark-field light source to provide dark-field illumination; receiving, by the optical detecting circuit, scattered lights of the dark-field light source; executing a dark-field computation process to obtain a first optical characteristic, and determining whether the first optical characteristic meets a first surface condition; in the negative, determining that a floor is a first type; in the affirmative, controlling the bright-field light source to provide bright-field illumination; receiving, by the optical detecting circuit, scattered lights of the bright-field light source; executing a bright-field computation process to obtain a second optical characteristic, and determining whether the second optical characteristic meets a second surface condition.

## Claims

### Claim 1

An optical sensing system, comprising:
a bright-field light source;
a dark-field light source;
an optical detecting circuit; and
a processing circuit configured to perform a floor type detection process, including:
controlling the dark-field light source to provide dark-field illumination on a floor in the target area;
receiving, by the optical detecting circuit, scattered lights of the dark-field light source from the floor in the target area;
executing a dark-field computation process to obtain a first optical characteristic of the target area according to the scattered lights of the dark-field light source received, and determining whether or not the first optical characteristic meets a first surface condition;
in response to determining that the optical characteristic of the floor in the target area does not meet the first surface condition, determining that a floor type of the floor in the target area is a first type;
in response to determining that the optical characteristic of the floor in the target area meets the first surface condition, controlling the bright-field light source to provide bright-field illumination on the floor in the target area;
receiving, by the optical detecting circuit, scattered lights of the bright-field light source from the floor in the target area;
executing a bright-field computation process to obtain a second optical characteristic of the target area according to the scattered lights of the bright-field light source received, and determining whether or not the second optical characteristic meets a second surface condition; and
in response to determining that the second optical characteristic meets a second surface condition, determining that the floor type of the floor in the target area is a second type.

### Claim 2 (depends on 1)

The optical sensing system according to claim 1, wherein the dark-field light source and the bright-field light source are located in a dark field and a bright field, respectively, and the dark field and the bright field are defined by a field of view of the optical detecting circuit and located beneath a cleaner housing.

### Claim 3 (depends on 1)

The optical sensing system according to claim 1, wherein the dark-field computation process includes:
obtaining light intensities of the scattered lights of the dark-field light source received by the optical detecting circuit; and
summing the light intensities obtained from the target area to obtain an overall intensity.

### Claim 4 (depends on 3)

The optical sensing system according to claim 3, wherein the overall intensity of the target area is taken as the first optical characteristic, and the step of determining whether or not the first optical characteristic meets the first surface condition includes:
determining whether or not the overall intensity is greater than or equal to a first threshold;
in response to determining that the overall intensity is greater than or equal to the first threshold, determining that the first optical characteristic meets the first surface condition; and
in response to determining that the overall intensity is not greater than or equal to the first threshold, determining that the first optical characteristic does not meet the first surface condition.

### Claim 5 (depends on 1)

The optical sensing system according to claim 1, wherein the bright-field light source includes a linear light source.

### Claim 6 (depends on 5)

The optical sensing system according to claim 5, wherein the bright-field computation process includes:
obtaining an optical profile of the floor in the target area according to light intensities of the scattered lights of the bright-field light source received by the optical detecting circuit.

### Claim 7 (depends on 6)

The optical sensing system according to claim 6, wherein the optical profile of the floor in the target area is taken as the second optical characteristic, and the step of determining whether or not the second optical characteristic meets the second surface condition includes:
obtaining a difference between the optical profile of the target area and a reference optical profile; and
determining whether or not the difference exceeds a second threshold;
in response to determining that the difference exceeds the second threshold, determining that the second optical characteristic meets the second surface condition; and
in response to determining that the difference does not exceed the second threshold, determining that the second optical characteristic does not meet the second surface condition.

### Claim 8 (depends on 7)

The optical sensing system according to claim 7, wherein the floor type detection process further includes:
in response to determining that the second optical characteristic does not meet the second surface condition, determining that the floor type is the first type.

### Claim 9 (depends on 1)

The optical sensing system according to claim 1, wherein the first type includes hard floors, the second type includes a carpet.

### Claim 10

An optical sensing method, comprising:
configuring a processing circuit to perform a floor type detection process, including:
controlling a dark-field light source to provide dark-field illumination on a floor in the target area;
receiving, by an optical detecting circuit, scattered lights of the dark-field light source from the floor in the target area;
executing a dark-field computation process to obtain a first optical characteristic of the target area according to the scattered lights of the dark-field light source received, and determining whether or not the first optical characteristic meets a first surface condition;
in response to determining that the optical characteristic of the floor in the target area does not meet the first surface condition, determining that a floor type of the floor in the target area is a first type;
in response to determining that the optical characteristic of the floor in the target area meets the first surface condition, controlling a bright-field light source to provide bright-field illumination on the floor in the target area;
receiving, by the optical detecting circuit, scattered lights of the bright-field light source from the floor in the target area;
executing a bright-field computation process to obtain a second optical characteristic of the target area according to the scattered lights of the bright-field light source received, and determining whether or not the second optical characteristic meets a second surface condition; and
in response to determining that the second optical characteristic meets a second surface condition, determining that the floor type of the floor in the target area is a second type.

### Claim 11 (depends on 10)

The optical sensing system according to claim 10, wherein the dark-field light source and the bright-field light source are located in a dark field and a bright field, respectively, and the dark field and the bright field are defined by a field of view of the optical detecting circuit and located beneath a cleaner housing.

### Claim 12 (depends on 10)

The optical sensing method according to claim 10, wherein the dark-field computation process includes:
obtaining light intensities of the scattered lights of the dark-field light source; and
summing the light intensities of the scattered lights of the dark-field light source to obtain an overall intensity.

### Claim 13 (depends on 12)

The optical sensing method according to claim 12, wherein the overall intensity of the target area is taken as the first optical characteristic, and the step of determining whether or not the first optical characteristic meets the first surface condition includes:
determining whether or not the overall intensity is greater than or equal to a first threshold;
in response to determining that the overall intensity is greater than or equal to the first threshold, determining that the first optical characteristic meets the first surface condition; and
in response to determining that the overall intensity is not greater than or equal to the first threshold, determining that the first optical characteristic does not meet the first surface condition.

### Claim 14 (depends on 10)

The optical sensing method according to claim 10, wherein the bright-field light source includes a linear light source.

### Claim 15 (depends on 13)

The optical sensing method according to claim 13, wherein the bright-field computation process includes:
obtaining an optical profile of the floor in the target area according to light intensities of the scattered lights of the bright-field light source received.

### Claim 16 (depends on 15)

The optical sensing method according to claim 15, wherein the optical profile of the floor in the target area is taken as the second optical characteristic, and the step of determining whether or not the second optical characteristic meets the second surface condition includes:
obtaining a difference between the optical profile of the target area and a reference optical profile; and
determining whether or not the difference exceeds a second threshold;
in response to determining that the difference exceeds the second threshold, determining that the second optical characteristic meets the second surface condition; and
in response to determining that the difference does not exceed the second threshold, determining that the second optical characteristic does not meet the second surface condition.

### Claim 17 (depends on 16)

The optical sensing method according to claim 16, wherein the floor type detection process further includes:
in response to determining that the second optical characteristic does not meet the second surface condition, determining that the floor type is the first type.

### Claim 18 (depends on 10)

The optical sensing method according to claim 10, wherein the first type includes hard floors, the second type includes a carpet.