JP2024029616A - Human body shape determination method - Google Patents

Abstract

An object of the present invention is to provide a device that detects when a cared person leaves the bed and falls. [Solution] Using 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, measurements were made for each unit sweep angle θ in an unoccupied room. The distance is the maximum distance for each sweep angle, and if the distance of the sweep angle becomes shorter than the maximum distance after the elapse of time, it is assumed that a human body is detected.For the sweep angle of the human body detection part, the value obtained by multiplying the distance by tanθ is calculated as the partial value. If the total partial length of the total partial length is greater than the threshold for determining whether it is a fall or a foot, it is determined that the fall is a fall, and if the total partial length is smaller than the threshold, it is determined that the fall is a foot. [Selection diagram] Figure 1

Description

The present invention monitors the movements of the care recipient indoors and detects critical situations such as falling or leaving the bed.

Due to the increase in the elderly population and the decrease in the number of caregivers, the burden on caregivers is increasing, and we are developing products that utilize information technology to reduce the burden on caregivers and improve the quality of care. is required.

If a non-caregiver falls indoors at a nursing home and suffers a broken bone or bleeding, it could become serious if not treated promptly.
Additionally, if the person being cared for gets out of bed at night, there is a possibility that the person may fall or wander. In the event of a fall or wandering, caregivers must be promptly notified and appropriate assistance provided.

Special table 2006-522956 JP2022-72765 JP2014-149731

Patent Document 1 is a method of determining whether a person is standing upright or lying on the floor based on images taken by a camera installed at a high place.
Patent Document 2 is a method of extracting a bed area through image processing using a camera installed at a high place, and detecting actions such as leaving the bed, falling, and falling.
Both methods are methods of processing images, and since distance factors are not taken into account in images, erroneous determination may occur depending on the location where the error occurs.
In addition, images require processing such as blurring to protect the privacy of the cared person.
Patent Document 3 is a system that infers the body position of a care recipient on a bed using images from a three-dimensional infrared laser and camera installed at a high place, and the equipment is installed at a high place in the same way as Patent Documents 1 and 2. In addition, there are problems in that the system has to be constructed using complicated equipment because it uses both images and a three-dimensional infrared laser, making the system expensive.

Since the conventional technology mentioned above uses a camera, it is necessary to install the camera at a high place, it requires processing measures such as blurring to maintain privacy, and there is no distance information. There are problems such as the possibility of erroneous judgments.

The present invention aims to solve these problems in the prior art, and provides a method that is easy to install, can monitor the entire room without contact, and can reliably detect falls and leaving the bed.

In a radar scanner that can continuously rotate and measure the horizontal distance and sweep angle to a reflector installed on the floor,
The distance measured for each unit sweep angle θ in an unoccupied room is the maximum distance for each sweep angle,
If the distance of the sweep angle becomes shorter than the maximum distance after the elapse of time, it is assumed that a human body has been detected.
For the sweep angle for human body detection, the partial length is the distance multiplied by tanθ,
If the total length of the parts is greater than the threshold for determining whether it is a fall or a foot fall, it is considered a fall.
If the total partial length is smaller than the threshold, it is determined to be a leg.

The present invention makes it possible to easily install equipment, ensure privacy, accurately detect falls or get out of bed in the cared person's room, and enable quick assistance, thereby increasing the safety of the cared person. Reduce the labor burden on caregivers.

A plan view showing the laser scanner sweep situation when a human body falls near the center of the room. A plan view showing the laser scanner sweep situation when a human body falls near the entrance of a room A plan view showing the scanning status of the laser scanner when a foot is detected near the bed in the room. A plan view showing the scanning status of the laser scanner when a foot is detected at a position far from the bed in the room. A plan view showing the laser scanner sweeping situation in an unoccupied room. Calculation table for calculating the sweep angle and distance of the radar scanner from Figures 1 to 5 to detect human bodies and feet.

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

The sweep height of a radar scanner that can measure the horizontal distance to a reflector placed on the floor is approximately 5 cm at the thinnest part of a human hand or foot, so if a person falls down, they can measure the whole body thoroughly. In order to do so, it is desirable that the height be 5 cm or less above the floor.
In addition, in order to accurately scan 5 cm or less, the leveling of the radar scanner must be accurate.
Since the laser beam is swept less than 5 cm above the floor, it is difficult to see the laser beam, but it is recommended to use a seriously safe laser scanner of laser class 1.

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,
The distance measured for each unit sweep angle θ in an unoccupied room is the maximum distance for each sweep angle,
If the distance of the sweep angle becomes shorter than the maximum distance after the elapse of time, it is assumed that a human body is detected.
For the sweep angle of the human body detection part, the partial length is the distance multiplied by tanθ,
If the total length of the parts is greater than the threshold for determining whether it is a fall or a foot fall, it is considered a fall.
If the total partial length is smaller than the threshold, it is determined to be a foot.

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

It is possible to detect a fall of a human body even if the radar scanner is installed in any position 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 near the bedside position, it is not necessary to specify the sweep angle and distance.

If the minimum distance of the newly appeared human body is greater than the threshold (approximately 1 m) for determining that it is next to the bed,
It is determined that a caregiver has entered the room from outside the room, and until it is determined that the caregiver has left the room,
That is, the determination of getting out of bed and falling down is stopped until no human body is detected.

If a human body that newly appeared next to the bed then moves from the side of the bed and can no longer be detected, it is determined that the human body has wandered around after leaving the room.

FIG. 5 is a plan view showing the scanning situation of the laser scanner 1 in an unoccupied room. The radially extending lines represent the sweep angle and distance 2 between the laser scanner 1 and the reflective object, and the reflective object other than the wall of the room is the bed. There are 3 legs and 4 furniture. The bed exists on four bed legs 3, which are not depicted in FIGS. 1 to 5.
The laser scanner 1 of the embodiment continuously sweeps the room counterclockwise from a reference angle of 0 degrees at every unit sweep angle θ (5 degrees), but in order to grasp the shape of the human body 5 more accurately, The smaller the unit sweep angle θ, the better.
The distance for each sweep angle of an unoccupied room is set as the maximum distance, and is written in the maximum distance column of the FIG. 5 column of FIG. 6, and is shared as the maximum distance in the embodiments from FIGS. 1 to 4.

FIG. 1 is a plan view showing the sweeping situation of the laser scanner 1 when a human body 5 falls near the center of the room, and the radially spreading lines represent the sweep angle and distance 2 between the laser scanner 1 and the reflecting object.
The distance, partial length (value obtained by multiplying the distance by tanθ of the unit sweep angle θ), and sweep angle of the sweep angle at which the human body 5 was detected are listed in the distance column, partial length column, and sweep angle column in the first column of FIG. do.

FIG. 2 is a plan view showing the sweeping situation of the laser scanner 1 when the human body 5 falls near the entrance of a room, and the radially spreading lines represent the sweep angle and distance 2 between the laser scanner 1 and the reflecting object.
The distance of the sweep angle at which the human body 5 was detected, the partial length (the value obtained by multiplying the distance by tanθ of the unit sweep angle θ), and the sweep angle are listed in the distance column, partial length column, and sweep angle column in the second column of FIG. do.

FIG. 3 is a plan view showing the sweeping situation of the laser scanner 1 when the foot 6 is detected near the bed in the room, and the radially extending lines represent the sweep angle and distance 2 between the laser scanner 1 and the reflective object.
The distance of the sweep angle at which the human body 5 was detected, the partial length (the value obtained by multiplying the distance by tanθ of the unit sweep angle θ), and the sweep angle are listed in the distance column, partial length column, and sweep angle column in the 3rd column of FIG. do.

FIG. 4 is a plan view showing the sweeping situation of the laser scanner 1 when the foot 6 is detected at a position away from the bed in the room, and the radially spreading lines indicate the sweep angle and distance 2 between the laser scanner 1 and the reflecting object. represent.
The distance of the sweep angle at which the human body 5 was detected, the partial length (the value obtained by multiplying the distance by tanθ of the unit sweep angle θ), and the sweep angle are listed in the distance column, partial length column, and sweep angle column in the 4th column of FIG. do.

Figure 6 summarizes the data from Figures 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.
The minimum distance, total partial length, and center angle from FIG. 1 to FIG. 4 are listed at the bottom of the table.
The minimum distance is used to calculate the closest distance from the laser scanner 1 to the human body 5 and to determine whether that distance is near the bed or far from the bed.
If the position where the human body 5 first appeared is near the bed, it is determined that the non-caregiver got off the bed or fell, and if it is not near the bed, it is determined that the caregiver entered from the entrance, and the caregiver By stopping the detection of falls and leaving the bed of the cared person until the carer leaves the room, it is possible to prevent false detection of the cared person leaving the bed or falling.
If the total length of the human body 5 detected by the laser scanner 1 is larger than a threshold value for determining the length of the fallen human body 5 and the length of the legs 6, it is determined that the fall has occurred, and if it is smaller than the threshold value, it is determined that the length of the legs 6.
The total length of the parts in the case of falling in FIGS. 1 and 2 is about 70 cm, and the part length in the case of the leg 6 in FIGS. 3 and 4 is about 40 cm, which shows a clear difference. If the threshold value for determining whether a fall is caused by the foot 6 is 50 cm, it is possible to reliably determine whether the foot 6 is a fall.
The angle is calculated from the center of the collection, and if this angle changes over time, it can be determined that the human body 5 is moving.

INDUSTRIAL APPLICATION This invention is utilized in a hospital and a nursing care facility in order to improve the safety of a cared person, and to reduce the workload of a caregiver.

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,
The distance measured for each unit sweep angle θ in an unoccupied room is the maximum distance for each sweep angle,
If the distance of the sweep angle becomes shorter than the maximum distance after the elapse of time, it is assumed that a human body has been detected.
For the sweep angle of the human body detection part, the partial length is the distance multiplied by tanθ,
If the total length of the parts is greater than the threshold for determining whether it is a fall or a foot fall, it is considered a fall.
A human body shape determination method characterized by a logic that determines that it is a foot if the total partial length is smaller than a threshold value. The human body shape determination method according to claim 1,
Calculate the center angle of the sweep angle of the appearance part of the human body,
A human body shape determination method characterized by determining the movement of the human body based on changes in the central angle over time. 2. The human body shape determining method according to claim 1, characterized in that the radar scanner is installed under the bed close to the bedside position. In the human body shape determination method according to claim 3, if the minimum distance of the newly appeared human body is larger than the threshold (approximately 1 m) for determining that the human body is next to the bed, it is determined that a caregiver has entered the room from outside, and the human body is A human body shape determination method characterized in that determination of getting out of bed and falling down is stopped until no more is detected. 5. The human body shape determination method according to claim 4, wherein the human body newly appearing next to the bed is
The human body shape determination method is characterized in that if the human body is no longer detected after moving from the side of the bed, it is determined that the human body has wandered after leaving the room.

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