JP7186327B1 - Human body shape determination method - Google Patents

Abstract

A device for detecting a cared person's getting out of bed and falling is provided. A radar scanner capable of continuous rotational measurement of the horizontal distance to a reflector installed on the floor and the sweep angle that is added for each unit sweep angle θ is used to measure each unit sweep angle θ in an unmanned room. The distance is the maximum distance for each sweep angle, and when the distance of the sweep angle becomes shorter than the maximum distance after the passage of time, it is detected as a human body. If the total partial length obtained by totaling the partial lengths is larger than a threshold for determining whether it is a fall or a foot, it is judged to be a fall, and if the total partial length is smaller than the threshold, it is judged to be a foot. [Selection drawing] Fig. 1

Description

The present invention monitors the movement of the person being cared for in the room and detects a critical situation such as a fall or getting out of bed.

As the population of elderly people increases and the number of caregivers decreases, the burden on caregivers tends to increase more and more. is required.

If a non-caregiver falls indoors in a care facility and has a broken bone or bleeding, it may become serious if immediate treatment is not provided.
In addition, when the care recipient gets out of bed at night, there is a possibility of falling or wandering. Caregivers need to be notified promptly and provide appropriate assistance in any case of falling or wandering.

Special table 2006-522956 JP 2022-72765 JP 2014-149731

Patent Literature 1 discloses a method for determining whether a person is standing upright or lying on the floor based on an image captured by a camera installed at a high place.
Patent document 2 is a method of extracting a bed area by image processing of a camera installed at a high place, and detecting actions such as leaving the bed, falling, and falling.
Either method is a method of processing an image, and since distance elements are not taken into consideration in the image, an erroneous determination may occur depending on the position of occurrence.
In addition, the image requires processing such as blurring to protect the privacy of the care receiver.
Patent Document 3 is a system for estimating the body position of a care recipient on a bed using a three-dimensional infrared laser and camera images installed at a high place. There is a problem that the system cost is expensive due to the complicated equipment configuration to use the image and the three-dimensional infrared laser.

Since the above conventional technology uses a camera, the camera must be installed at a high place, processing such as blurring is required to ensure privacy, and there is no distance information. There are problems such as the possibility of erroneous determination.

An object of the present invention is to solve such problems in the prior art, and to provide a method that is easy to install, monitors the entire room in a non-contact manner, and can reliably detect falling or leaving the bed.

In the radar scanner that can continuously rotate and measure the horizontal distance and sweep angle to the reflector installed on the floor,
Let the distance measured per unit sweep angle θ in an empty room be the maximum distance per sweep angle,
If the sweep angle distance becomes shorter than the maximum distance after the elapse of time, the human body is detected.
For the sweep angle for human body detection, the partial length is the value obtained by multiplying the distance by tanθ.
If the total partial length, which is the sum of the partial lengths, is greater than the threshold for determining whether it is a fall or a foot, it is considered a fall,
If the total partial length is smaller than the threshold, it is determined as a foot.

The present invention makes it easy to install the equipment, secures privacy, and can accurately detect falling or getting out of bed of the care recipient in the room, enabling prompt assistance, thereby enhancing the safety of the care recipient. Reduce the workload of caregivers.

Top view showing the sweeping situation of the laser scanner when the human body falls near the center of the room Top view showing the sweeping situation of the laser scanner when the human body falls near the entrance of the room Top view showing the sweeping situation of the laser scanner when the foot is detected near the bed in the room Top view showing the sweeping situation of the laser scanner when the foot is detected at a position away from the bed in the room Top view showing the sweeping situation of the laser scanner in an unmanned room Calculation table for collecting the sweep angle and distance of the radar scanner from Fig. 1 to Fig. 5 and detecting the human body and feet

The laser scanner used in the present invention is also called LiDAR (Light Detection and Ranging), rotates the laser beam two-dimensionally, and measures the distance of the sweep angle from the time when the reflected light returns.

The sweep height of a radar scanner that can measure the horizontal distance to a reflector installed on the floor is about 5 cm at the thinnest part of a human hand or foot. In order to do so, it is desirable to be 5 cm or less above the floor.
Also, in order to accurately scan 5 cm or less, the levelness of the radar scanner must be accurate.
The laser beam is hard to see because it is swept at 5 cm or less above the floor.

In a radar scanner that can continuously rotate and measure the horizontal distance to a reflector installed on the floor and the sweep angle that is added for each unit sweep angle θ,
Let the distance measured per unit sweep angle θ in an empty room be the maximum distance per sweep angle,
If the sweep angle distance becomes shorter than the maximum distance after the elapse of time, the human body is detected.
For the sweep angle of the human body detection part, the partial length is the value obtained by multiplying the distance by tan θ.
If the total partial length, which is the sum of the partial lengths, is greater than the threshold for determining whether it is a fall or a foot, it is considered a fall,
If the total partial length is smaller than the threshold, it is determined as a leg.

The central angle of the sweep angle of the detection part of the human body is calculated, and the movement of the human body is determined based on the change in the central angle over time.

It is possible to detect a fall of a human body by installing a radar scanner anywhere in the room, but when detecting a person leaving the bed, the distance and sweep angle must be specified according to the installation location. , if the radar scanner is installed under the bed close to the bed leaving position, it is unnecessary to specify the sweep angle and distance.

If the minimum distance of the newly appearing human body is larger than the threshold (approximately 1 m) that is judged to be next to the bed,
Until it is determined that the caregiver has entered the room from outside and the caregiver has left the room,
That is, until the human body is no longer detected, the determination of leaving the bed and falling is stopped.

If a human body newly appearing next to the bed moves away from the bedside and becomes undetectable, it is determined that the human body has wandered after leaving the room.

FIG. 5 is a plan view showing the sweeping situation of the laser scanner 1 in an unmanned room. The radial lines represent the sweep angle and the distance 2 between the laser scanner 1 and the reflecting object, and the reflecting objects other than the walls of the room are the beds. There are 3 legs and 4 furniture. The bed rests on four bed legs 3 which are not depicted in FIGS.
The laser scanner 1 of the embodiment continuously sweeps the room counterclockwise from the reference angle of 0 degrees at each unit sweep angle θ (5 degrees). The smaller the unit sweep angle θ, the better.
The distance for each sweep angle in an unoccupied room is the maximum distance and is listed in the maximum distance column of FIG. 5 column of FIG.

FIG. 1 is a plan view showing the sweeping state of the laser scanner 1 when the human body 5 falls near the center of the room, and the radial lines represent the sweep angle and the distance 2 between the laser scanner 1 and the reflector.
The distance, partial length (distance multiplied by tan θ of the unit sweep angle θ), and sweep angle at which the human body 5 is detected are described in the distance column, partial length column, and sweep angle column in column 1 of FIG. do.

FIG. 2 is a plan view showing the sweeping state of the laser scanner 1 when the human body 5 falls near the entrance of the room, and the radial lines represent the sweep angle and the distance 2 between the laser scanner 1 and the reflector.
The distance, partial length (distance multiplied by tan θ of the unit sweep angle θ), and sweep angle at which the human body 5 is detected are described in the distance column, partial length column, and sweep angle column in FIG. do.

FIG. 3 is a plan view showing the sweeping state of the laser scanner 1 when the foot 6 is detected near the bed in the room, and the radial lines represent the sweep angle and the distance 2 between the laser scanner 1 and the reflecting object.
The distance, partial length (value obtained by multiplying the distance by tan θ of the unit sweep angle θ), and sweep angle at which the human body 5 is detected are described in the distance column, partial length column, and sweep angle column of FIG. do.

FIG. 4 is a plan view showing the sweeping state of the laser scanner 1 when the foot 6 is detected at a position away from the bed in the room. show.
The distance, partial length (value obtained by multiplying the distance by tan θ of the unit sweep angle θ), and sweep angle at which the human body 5 is detected are described in the distance column, partial length column, and sweep angle column in FIG. do.

FIG. 6 summarizes the data from FIGS. 1 to 5 in a table. However, the maximum value of the scanning angle from 105 degrees to 345 degrees in FIG. 6 is omitted because it does not affect the detection of the human body 5 in the embodiment.
At the bottom of the table, the minimum distances, total partial lengths, and central angles of FIGS. 1 to 4 are listed.
The minimum distance is used to calculate the closest distance from the laser scanner 1 to the human body 5 and determine whether that distance is near the bed or away from the bed.
If the position where the human body 5 first appears is near the bed, it is determined that the non-caregiver has left the bed or has fallen, and if it is not near the bed, it is determined that the caregiver has entered through the entrance. False detection of getting out of bed and falling can be prevented by stopping the detection of the care recipient's fall and getting out of bed until the care recipient leaves.
If the total partial length of the human body 5 detected by the laser scanner 1 is larger than a threshold for determining the length of the fallen human body 5 and the length of the leg 6, it is determined that the body has fallen, and if it is smaller than the threshold, the leg 6 is determined.
The total partial length in the case of falling in FIGS. 1 and 2 is about 70 cm, and the partial length in the case of foot 6 in FIGS. 3 and 4 is about 40 cm, which is a clear difference. If the threshold for judging the fall and the foot 6 is 50 cm, the fall and the foot 6 can be judged reliably.
The angle calculates the angle of the center of the set, and if this angle changes with time, it can be determined that the human body 5 is moving.

The present invention is used in hospitals and nursing homes to improve the safety of care recipients and reduce the workload of caregivers.

1 Laser Scanner 2 Laser Scanner Sweep Angle and Distance 3 Bed Feet 4 Furniture 5 Human Body 6 Feet

Claims (5)

In a radar scanner that can continuously rotate and measure the horizontal distance to a reflector installed on the floor and the sweep angle that is added for each unit sweep angle θ,
Let the distance measured per unit sweep angle θ in an empty room be the maximum distance per sweep angle,
If the sweep angle distance becomes shorter than the maximum distance after the elapse of time, the human body is detected.
For the sweep angle of the human body detection part, the partial length is the value obtained by multiplying the distance by tan θ.
If the total partial length, which is the sum of the partial lengths, is greater than the threshold for determining whether it is a fall or a foot, it is considered a fall,
A human body shape determination method characterized by the logic of determining a leg when the total partial length is smaller than a threshold. The human body shape determination method according to claim 1,
Calculate the central angle of the sweep angle of the appearance of the human body,
A method for judging the shape of a human body characterized by judging the movement of the human body based on the change of the central angle with the lapse of time. 2. The human body shape determination method according to claim 1, wherein the radar scanner is installed under the bed near a bed leaving position. In the human body shape determination method according to claim 3, when the minimum distance of the newly appeared human body is larger than the threshold (approximately 1 m) for determining that it is next to the bed, it is determined that the caregiver has entered the room from outside, and the human body A method for judging the shape of a human body characterized by suspending the judgment of getting out of bed and falling until is no longer detected. The human body shape determination method according to claim 4, wherein the human body newly appearing next to the bed is
A method for judging the shape of a human body, characterized by judging that the person has wandered after leaving the room when the person moves from the side of the bed after that and the human body cannot be detected.

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