JP3939224B2 - Area monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an area monitoring apparatus, and more particularly to an area monitoring apparatus that can monitor a movement that is about to go out of a target area.
[0002]
[Prior art]
In nursing homes such as nursing homes, residents have fallen out of bed in the middle of the night, causing accidents such as breaking their leg bones. Also in hospitals, for example, when a patient wakes up from anesthesia after surgery, the pain may move violently on the bed and fall. In addition, an infant may fall from the bed. In order to respond quickly to such an accident, conventionally, an apparatus for monitoring the state of a person on a bed based on a time transition of a pressure distribution detected by a load sensor or a pressure sensor has been proposed.
[0003]
[Problems to be solved by the invention]
However, according to the conventional apparatus as described above, for example, it can be detected that a person is no longer on the bed (leaves the bed), but it is difficult to detect a fall from the bed or a movement that is likely to fall. In other words, it was difficult to predict the fall. Furthermore, since the signal to be measured is very small, a high-performance signal amplifier or some kind of signal processing is necessary to acquire and detect a stable signal, which has become a complicated and large-scale system. .
[0004]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a simple area monitoring apparatus as well as to detect a movement of an object going outside a target area.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a region monitoring apparatus 1 according to the invention according to claim 1 includes a three-dimensional sensor 10 that acquires three-dimensional information in a target region, for example, as shown in FIGS. 1 and 2; Height change detection means 22 for detecting a change in the height of the object 2 in the target area based on the three-dimensional information, and detecting a region in the target area where the height has changed. The position detecting means 23 for detecting the position of the object 2 and the movement monitoring means 24 for monitoring the movement of the object 2 to go out of the target area are provided. The position of the object 2 detected by the means 23 exists in a specific area within the object area, and the change in the height of the object 2 detected by the height change detection means 22 is a predetermined amount or more. Sometimes the object 2 is out of the target area Configured to determine the movement of the cornerstone The movement monitoring means 24 is configured to detect the movement of the object 2, the position of the object 2 is in the specific area, and the movement speed of the object 2 immediately before reaching the position is a predetermined threshold value; Configured to detect a movement to go out of the target area when The
[0006]
Moreover, the said area | region monitoring apparatus 1 is good to provide the boundary division member provided in the boundary of the said target area and the periphery one step higher than the said target area. If comprised in this way, not only can the target object 2 inadvertently go out of a target area, for example, but a height change will become large when the target object 2 goes out of a target area. .
[0007]
If comprised in this way, since it has the three-dimensional sensor 10, the height change detection means 22, and the position detection means 23, since the position of the target object 2 can be detected, it can be set as a simple area | region monitoring apparatus. it can. Furthermore, it comprises a movement monitoring means 24, and the movement monitoring means 24 is By position detection means 23 The position of the detected object 2 Before Specific area within the target area Exist and , Detected by height change detection means 22 When the change in the height of the object 2 is a predetermined amount or more , Object 2 is Movement to go out of the target area Judgment For example, the object moves over the fence Judgment By doing so, it is possible not only to detect the movement of the object going out of the target area, but also to provide a simple area monitoring device.
[0008]
In addition, as described in claim 2, in the region monitoring device 1 described in claim 1, the motion monitoring unit 24 is configured such that the change in the height of the object 2 is equal to or greater than a predetermined amount, and more than the predetermined amount. It is preferable that the apparatus is configured to detect a movement to go out of the target area when the height change area is a predetermined area or more.
[0009]
With this configuration, for example, when the position of the target object is a specific area, even if only a part of the area in which the height change of the target object 2 is greater than or equal to a predetermined amount is included, the object 2 goes out of the target area. Since it is possible to prevent the movement to be detected, the reliability of the movement monitoring is increased.
[0010]
Also As mentioned above, above In the area monitoring device 1, the motion monitoring means 24 is configured to detect the movement of the object 2; the position of the object 2 is in the specific area, and the movement speed of the object 2 immediately before reaching the position Configured to detect a movement to go out of the target area when the threshold exceeds a predetermined threshold Be done .
[0011]
With this configuration, for example, even when the object 2 suddenly enters a specific area and tries to go out of the target area as it is, the movement of going out of the target area quickly is detected. can do.
[0012]
And claims 3 As claimed in claim 1. Or claim 2 In the area monitoring apparatus 1 described in the above, the position detecting unit 23 determines an existing area where the object 2 exists based on the detected height change, and includes the determined existing area. It is preferable that a region obtained by enlarging the existence region by a predetermined range is calculated, and the position of the object 2 is detected with priority on the enlarged region.
[0013]
With this configuration, for example, since the position of the object 2 is detected from an area where the object 2 is likely to exist, the time required to detect the position of the object 2 can be shortened, and the processing speed can be increased. .
[0014]
And claims 4 Claims 1 to 3 In the region monitoring apparatus 1 according to any one of the above, for example, as shown in FIG. 7, the three-dimensional sensor 101 includes a projection unit 110 that projects a bright line or a plurality of bright points onto the target region; An imaging means 111 for imaging the pattern formed by the above-mentioned method; and a height calculation unit 118 for calculating the height of the object by trigonometry based on the captured pattern image and reference image.
[0015]
With this configuration, the three-dimensional sensor 101 captures the bright line projected on the target area by the projection unit 110 or a pattern formed by a plurality of bright spots by the imaging unit 111 and the height calculation unit 118. Since the height of the object is calculated by trigonometry based on the captured pattern image and the reference image, the height of the object can be measured accurately even though it is simple. When the pattern is a bright line, for example, the continuous height in the bright line direction can be measured.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the mutually same or equivalent member, and the overlapping description is abbreviate | omitted.
[0017]
FIG. 1 is a schematic external view of a fall prediction device 1 as an area monitoring device according to an embodiment of the present invention. The fall prediction device 1 includes a three-dimensional sensor 10 that acquires three-dimensional information in a target area, and an arithmetic device 20. Moreover, the fall prediction apparatus 1 is configured to monitor the target area. In the present embodiment, the object is the person 2. Further, in the present embodiment, the target area is a target area having a height higher than the periphery, and is typically on the bed 3. The three-dimensional sensor 10 has a plurality of measurement points in the target region, and can measure the height at each measurement point. In the present embodiment, the three-dimensional information is the coordinates of a plurality of measurement points on the bed 3 and the height measured at each point. In other words, the three-dimensional information is a height distribution on the bed 3. Further, the target area may be detected from the three-dimensional information. In this case, first, three-dimensional information of the area including the target area is acquired, and based on this three-dimensional information, the target area having a height higher than the periphery, that is, the bed 3 is detected. Since the upper surface of the bed 3 is higher than the periphery, it can be easily detected from the three-dimensional information. By doing in this way, the environment setting operation | work at the time of installing the fall prediction apparatus 1 becomes simple, and installation becomes easy. Moreover, you may detect the detection of a target area | region by detecting the below-mentioned fence 6 based on three-dimensional information.
[0018]
A person 2 lies on the bed 3 in the figure. In addition, a bedding 4 is hung on the person 2 and covers a part of the person 2 and a part of the bed 3. In this case, the three-dimensional sensor 10 acquires the height distribution of the upper surface of the bedding 4. When the bedding 4 is not used, the three-dimensional sensor 10 acquires the height distribution of the person 2 itself. In addition, the bed 3 is provided with a fence 6 provided as a boundary partition member that is provided at the boundary between the target area and the periphery and is one step higher than the target area. The fence 6 is also a fall prevention means for preventing, for example, the person 2 from rolling down. The fence 6 is attached to both side surfaces 3 a of the bed 3. The fence 6 has a height that prevents the person 2 from rolling down due to, for example, turning over, for example, a height of about 20 to 50 cm from the upper surface of the bed 3. Further, the bed 3 is formed with end plates 3b formed at both ends higher than the upper surface of the bed 3.
[0019]
A three-dimensional sensor 10 is disposed on the upper portion of the bed 3. The three-dimensional sensor 10 will be described in detail later. The three-dimensional sensor 10 and the arithmetic device 20 are electrically connected. In the drawing, the three-dimensional sensor 10 and the arithmetic unit 20 are shown as separate bodies, but may be configured integrally. If it does in this way, the fall prediction apparatus 1 can be reduced in size.
[0020]
With reference to the block diagram of FIG. 2, the structural example of the fall prediction apparatus 1 is demonstrated. The three-dimensional sensor 10 is connected to the arithmetic device 20 and is configured to output the acquired three-dimensional information to the arithmetic device 20. The arithmetic unit 20 may be configured to acquire three-dimensional information from the three-dimensional sensor 10 in time series. The computing device 20 is a computer such as a personal computer or a microcomputer. Further, the arithmetic unit 20 has a control unit 21 that controls the drop prediction device 1.
[0021]
A storage unit 31 is connected to the control unit 21. The storage unit 31 may store the three-dimensional information acquired from the three-dimensional sensor 10 in time series. The storage unit 31 can store data such as calculated information. Furthermore, the storage unit 31 includes a specific area registration unit 32 that registers in advance a specific area, which will be described later with reference to FIG.
[0022]
The control unit 21 is connected to an input device 35 for inputting information for operating the fall prediction device 1 and an output device 36 for outputting a result processed by the fall prediction device 1. The input device 35 is, for example, a touch panel, a keyboard, or a mouse, and the output device 36 is, for example, a display or a printer. Although the input device 35 and the output device 36 are illustrated as being externally attached to the arithmetic device 20 in this figure, they may be built in. Further, the input device 35 may be, for example, a switch that can start or cancel monitoring (fall prediction) in the target area, and the output device 36 may be, for example, an LED as an operation indicator. If it does in this way, the fall prediction apparatus 1 can be comprised simply. In particular, when the three-dimensional sensor 10 and the arithmetic unit 20 are configured integrally, it is preferable to configure in this way. By doing in this way, the fall prediction apparatus 1 can be made simpler and small.
[0023]
In the control unit 21, a height change detection unit 22 as a height change detection unit that detects a change in height in the target region based on the three-dimensional information acquired from the three-dimensional sensor 10, and a height change Based on the change in height detected by the detection unit 22, a position detection unit 23 serving as a position detection unit that detects the position of the person 2, and a movement for monitoring the movement of the person 2 going out of the target area A drop prediction unit 24 as monitoring means is provided. The position of the person 2 detected by the position detection unit 23 is, for example, the position of the area where the person 2 is present, and the position of the person 2 is typically the barycentric position of the area where the person 2 is present.
[0024]
Detection of a change in height by the height change detection unit 22 is performed by calculating a difference between the three-dimensional information acquired from the three-dimensional sensor 10 and the three-dimensional information stored in the storage unit 31 in time series. Detect changes in height at each measurement point in the region. In other words, a change in height at each measurement point in the target region is detected by taking a difference between the latest three-dimensional information acquired and the three-dimensional information acquired in the past. The three-dimensional information acquired in the past is typically three-dimensional information acquired immediately before (the past) the latest three-dimensional information. In this case, the three-dimensional information is acquired from the three-dimensional sensor 10 at regular time intervals. The acquisition interval of the three-dimensional information is, for example, about 0.1 to 3 seconds, preferably about 0.1 to 0.5 seconds. Further, it is effective to acquire the three-dimensional information in a shorter time and perform the averaging or filtering process, for example, because the influence of random noise can be reduced. The acquisition interval may be a relatively long time, for example, about 5 to 20 seconds. In this case, for example, it becomes easy to detect the rising motion of the person 2.
[0025]
The three-dimensional information or height change acquired from the three-dimensional sensor 10 may be a moving average value or a period average value of values acquired a certain number of times in the past or acquired within a certain period in the past. By doing so, random noise and sudden noise caused by sunlight flickering through the window can be reduced, and erroneous determination of peak positions and zero cross positions (intersections where signs are reversed) can be reduced. .
[0026]
Further, the position detection unit 23 determines the presence region where the person 2 exists based on the height change detected by the height change detection unit 22, and determines the position of the center of gravity of the determined presence region as the position of the person 2. It is good to comprise. In this way, the position of the person 2 can be detected not by a region having an area but by a point, so that a slight movement of the person 2 can be detected relatively sensitively.
[0027]
The determination of the existence area is, for example, paying attention to the height change of an arbitrary measurement point. The number of measurement points whose direction of change is the same as the target position is counted, and if the number is equal to or greater than a predetermined value, this range is regarded as an existing region.
[0028]
Further, the position detection unit 23 calculates an area that includes the determined existence area and is an enlargement of the existence area by a predetermined range, and detects the position of the person 2 with priority on the enlarged area. You may comprise so that it may perform. In the present embodiment, the acquisition interval of the three-dimensional information by the three-dimensional sensor 10 is set to a sufficiently short time compared to the movement of the person 2, so that the person 2 moves greatly during the acquisition interval. However, the next time the position of the person 2 is detected, it is considered that the person 2 exists at substantially the same position or in an adjacent region. Therefore, a method for detecting the position of the person 2 with priority given to an area obtained by enlarging the existing area by a predetermined range is effective. In this way, since the position of the person 2 is detected with priority given to the region where the person 2 is likely to exist, the search time for the person 2 can be shortened, and the processing speed can be increased.
[0029]
Here, the fall prediction unit 24 will be described. As described above, the fall prediction unit 24 monitors the movement of the person 2 about to go out of the target area. Here, monitoring the movement of the person 2 trying to go out of the target area means, for example, predicting the fall of the person 2 from the bed 3 or detecting the fall of the person 2 from the bed 3. Furthermore, the fall predicting unit 24 is when the position of the person 2 detected by the position detecting unit 23 is a specific area in the target area, and when the change in the height of the person 2 is a predetermined amount or more. It is configured to detect a movement to go out of the target area. In other words, it is configured to predict the fall of the person 2. Hereinafter, detecting the movement to go out of the target area is referred to as predicting a fall. Here, the specific area is typically a target area, that is, a bed. 3 The upper peripheral portion and the region in the vicinity thereof (hereinafter simply referred to as the peripheral portion on the bed 3 when these are not distinguished). The fall prediction unit 24 is configured to output an alarm signal when the fall of the person 2 is predicted. The alarm signal is typically output to an alarm device 38 described later.
[0030]
FIG. 3 shows an example of the specific area. Moreover, although it is preferable to set a specific area | region as the whole peripheral part on the bed 3 like (a), as shown in (b), the location where the fall of the upper peripheral part on the bed 3 is easy to generate | occur | produce, For example, only the both side surfaces on the bed 3 may be used. In this way, only a portion where the drop is likely to occur can be set as the specific region, so that an efficient drop prediction can be performed.
[0031]
In the present embodiment, when the person 2 falls from the bed 3, the fence 6 is provided, so that the person 2 does not fall (falls) as it is turned over. Or get up and fall from the part without the fence 6. That is, before falling, a height change greater than a small body movement such as turning over is always detected at the peripheral edge of the bed 3. For this reason, the position of the person 2 is the specific region, that is, the peripheral edge on the bed 3, and the height change is a predetermined amount, typically a certain level or more. Here, the height change above a certain level is, for example, a height change above the height change detected when the person 2 gets up, for example, a height change above the height change corresponding to about 300 to 700 mm. is there.
[0032]
The fall prediction unit 24 is configured such that the person 2 detects a fall from within the target area. The fall prediction unit 24 detects the fall from the target area when the height change is not detected in the target area after predicting the fall. That is, it is configured to detect that the person 2 has fallen from the bed 3. The fall prediction unit 24 is configured to output an alarm signal when the fall of the person 2 is detected. The alarm signal is typically output to an alarm device 38 described later.
[0033]
Further, the fall predicting unit 24 predicts the fall of the person 2 when the change in the height of the person 2 is equal to or greater than a certain level and the area of the change in height greater than the certain level is equal to or greater than a predetermined area. It is good to configure. As described above, when the person 2 is likely to fall from the bed 3, a height change larger than a small body movement such as turning over at the periphery is surely detected. Furthermore, if the person 2 moves up to rise, this large change in height is detected, for example, in an area equal to or larger than the cross-sectional area of the head and torso of the person 2. For this reason, the drop is predicted when the region of a certain height change or more is a predetermined area or more. The predetermined area is typically about the cross-sectional area of the head of a standard person 2. By doing so, the movement in a small area that does not cause the fall, for example, when the sleeping person 2 is present at the position of the peripheral part of the bed 3, the movement with only the arms raised is dropped. Can be prevented (alarm is issued), so that the reliability of fall prediction is increased.
[0034]
In addition, the fall prediction unit 24 may be configured to detect the movement of the person 2. The detection of movement includes detection of the direction, speed, and distance of movement in addition to detection of presence / absence of movement. Further, the fall predicting unit 24 is configured to predict the fall of the person 2 when the position of the person 2 is in a specific area and the moving speed of the person 2 immediately before reaching the position exceeds a predetermined threshold value. Good. There is a case where the person 2 suddenly enters a specific area and falls as it is. In such a case, it is necessary to predict the fall quickly. For this reason, the fall prediction unit 24 is configured to predict the fall of the person 2 when the person 2 enters a specific area at a moving speed exceeding a predetermined threshold. The predetermined threshold is preferably about 2 to 5 km / h, for example.
[0035]
Furthermore, a state detection unit 25 that detects the state of the person 2 based on the change in height detected by the height change detection unit 22 is provided in the control unit 21. The state of the person 2 is, for example, a state of normal breathing, abnormal breathing and danger, body movement, for example, turning over. Further, the state detection unit 25 is configured to detect the respiration of the person 2 based on the change in height detected by the height change detection unit 22.
[0036]
The detection of respiration by the state detection unit 25 sets a predetermined upper and lower limit threshold for both or either of the amplitude and period (frequency) of the periodic change of the height change detected by the height change detection unit 22, It is compared with this threshold value to determine whether or not it is breathing, and breathing is detected. The upper and lower limit threshold values of the cycle may be set in a range including a person's breathing cycle, for example, a lower limit of 5 cycles per minute and an upper limit of 60 cycles per minute. By the way, although the respiratory rate of an adult exists in the range of about 5-30 times per minute, in the case of an infant, there exists a tendency for the respiratory rate to increase further. Similarly, the upper and lower limit thresholds of the amplitude may be set to a range including, for example, a person's breathing amplitude, for example, a value corresponding to a height change of about 1 mm for the lower limit and about 20 mm for the upper limit. Thereby, the detected respiration of the person 2 forms a waveform pattern.
FIG. 4 is a diagram showing an example of a respiratory waveform pattern.
[0037]
The state detection unit 25 may be configured to detect whether or not the person 2 is present on the bed 3 after the respiration of the person 2 is detected for a certain period of time, that is, to detect the presence of the person 2. The fall prediction device 1 may start the fall prediction of the person 2 on the condition that the person 2 is detected. The certain time is a time during which respiration can be detected stably, for example, 30 to 120 seconds, and more preferably 30 to 90 seconds.
[0038]
Further, the state detection unit 25 may detect the state of the person 2 in consideration of the following. For example, when the period of the respiratory pattern is disturbed in a short time, or when the period of the respiratory pattern changes suddenly, for example, spontaneous pneumothorax, lung diseases such as bronchial asthma, heart diseases such as congestive heart failure, Or it can be estimated that it is cerebrovascular disease, such as cerebral hemorrhage. Moreover, when the disappearance of the breathing pattern continues, it can be estimated that the breathing of the person 2 has stopped. And when a person's 2 body movement appears frequently instead of a breathing pattern in a short time, the situation where the person 2 suffers for some reason and is rampant can be estimated.
[0039]
In addition, the detection of the body movement of the person 2 can be easily detected because it fluctuates much more than when only respiration is detected from the height change. For this reason, the state detection unit 25 determines whether the person 2 is moving on the spot such as turning over or is moving up, such as getting up from the bed, depending on the position of the person 2 detected by the position detection unit 23. It can also be detected. Further, even when the person 2 makes periodic and small movements such as convulsions, an abnormality can be detected from the waveform pattern. In such a case, the waveform pattern in a state of further convulsions can be stored in the storage unit 31 and compared with the pattern to detect that the person 2 is convulsed.
[0040]
An example of normal and abnormal breathing patterns will be described with reference to FIG. The normal breathing pattern is a periodic pattern as shown in FIG. However, in the case of an adult, the normal range for the respiratory rate per minute is about 10 to 20 times. Abnormal breathing patterns occur, for example, when there is a physiological disorder in the body, such as Cheyne-Stokes breathing, central hyperventilation, ataxic breathing, or Kussmul's breathing. It is a breathing pattern that is considered.
[0041]
FIG. 5B shows a respiratory pattern of Cheyne-Stokes breathing, FIG. 5C shows a respiratory pattern of central hyperventilation, and FIG. 5D shows a respiratory pattern of ataxic breathing.
Further, FIG. 6 shows a disease name or a disease location when the above abnormal breathing pattern occurs.
[0042]
The state detection unit 25 determines whether the breathing pattern of the person 2 belongs to the breathing pattern of the person 2 by using the difference in the breathing frequency, the number of appearances, and the depth of each breathing pattern. Should be detected. The breathing pattern as described above may be stored in the storage unit 31. By doing in this way, by comparing with these patterns, it can be easily detected whether or not the breathing of the person 2 is normal.
[0043]
Furthermore, the state detection unit 25 indicates that the breathing of the person 2 is physiologically impaired in the body. Case When it is determined that the person 2 belongs to a breathing pattern that is considered to occur, the person 2 detects that the person 2 is breathing abnormally and is in a dangerous state. Physiologically damaged in the body Case The breathing pattern that is considered to occur in FIG. 5 is, for example, the breathing pattern described in FIG. The state of the person 2 detected in this way is output to the output device 36 and the alarm device 38 by the control unit 21, for example. The output contents include the detected respiratory rate (cycle) of the person 2 and the frequency of movement, the name of an abnormal breathing pattern, a disease name that is considered to cause the breathing, a diseased organ, a diseased part, and the like.
[0044]
Furthermore, the arithmetic unit 20 includes an alarm device 38 that issues an alarm. The alarm device 38 is configured to issue an alarm by inputting an alarm signal. The alarm device 38 falls when, for example, the fall prediction unit 24 predicts the fall of the person 2, when the fall is detected, or when the state detection unit 25 detects that the person 2 is in a dangerous state. It may be configured to issue an alarm when an abnormality such as a failure occurs in the prediction device 1. Further, the alarm device 38 is configured to issue different types of alarms according to the input alarm signal. Specifically, for example, a different alarm is set for each type of input alarm signal. Thereby, the user (administrator) of the apparatus can recognize that the fall of the person 2, for example, is predicted by the issued alarm. By doing so, it is possible to respond quickly to an abnormality, and thus reliability can be improved. In addition, the arithmetic unit 20 may be configured to notify the occurrence of an alarm to the outside via the interface 37 when the alarm device 38 is activated. In this figure, the alarm device 38 is illustrated as being externally attached, but may be provided internally.
[0045]
The arithmetic unit 20 is provided with an interface 37 for communicating with the outside. The interface 37 is configured to notify the outside when an alarm is issued by the alarm device 38, for example. The notification is based on, for example, the intensity of light including voice, characters, symbols, and indoor lighting, or vibration. The interface 37 has a function of connecting to a communication line such as a general telephone line, an ISDN line, a PHS line, or a mobile phone line. That is, for example, when the fall prediction device 1 is installed in a private house, it is possible to report to a medical facility such as a hospital by using the communication line. By doing so, for example, even if the place where the fall prediction device 1 is installed is far away, it is effective because it is possible to easily report that an alarm has been issued by using the communication line. . Further, the control unit 21 may be provided with a voice output function, and may report, for example, a warning or the state of the person 2 to the third party via the interface 37 by voice.
[0046]
Here, the three-dimensional sensor 10 will be described. The three-dimensional sensor 10 can typically acquire three-dimensional information in the target area in a non-contact manner. Hereinafter, an FG sensor used as a three-dimensional sensor in the present embodiment will be described.
[0047]
With reference to the conceptual perspective view of FIG. 7, the FG (fiber grating) sensor 101 used as the three-dimensional sensor 10 suitable for the fall prediction apparatus 1 of this Embodiment is demonstrated. The FG sensor 101 can acquire three-dimensional information of an object (person 2) existing in the target area. That is, the height distribution of the object can be measured. Here, for the sake of description, the target area will be described as the plane 102 and the target object as the object 103.
[0048]
The FG sensor 101 includes a bright spot projection device 110 as a projection unit that projects a plurality of bright spots on a target area, and an imaging device 111 as an imaging unit that captures a pattern 110a formed by the projection of the bright spot projection device 110. And. The pattern 110a is typically a plurality of bright spots arranged in a square lattice pattern. The bright spot has a substantially circular shape including an ellipse.
[0049]
In the figure, an object 103 is placed on the plane 102. Further, the orthogonal coordinate system XYZ is taken so that the XY axis is placed in the plane 102, and the object 103 is placed in the first quadrant of the XY coordinate system. On the other hand, a bright spot projector 110 and an imaging device 111 are arranged above the plane 102 on the Z axis in the drawing. The imaging device 111 images the object 103 on which the pattern 110 a is projected by the bright spot projection device 110.
[0050]
The imaging device 111 includes an imaging lens 111a and an imaging element 115. The image sensor 115 is typically a CCD camera. The imaging lens 111a of the imaging device 111 is typically arranged so that its optical axis coincides with the Z axis. The imaging lens 111a forms an image of the pattern 110a on the plane 102 or the object 103 on the imaging plane 115 ′ (image plane) of the image sensor 115. The imaging plane 115 ′ is typically a plane orthogonal to the Z axis. Further, an xy orthogonal coordinate system is taken in the imaging plane 115 ′ so that the Z axis passes through the origin of the xy coordinate system. The bright spot projection device 110 is arranged at an equal distance from the plane 2 with the imaging lens 111a and away from the imaging lens 111a by a distance d (base line length d) in the negative direction of the Y axis. A pattern 110 a formed by a plurality of bright spots 110 b is projected onto the object 103 and the plane 102 by the bright spot projector 110. Further, the y-axis direction is also the baseline direction of the trigonometric method used for calculating the height described later in FIG.
[0051]
The image sensor 115 is typically a CCD image sensor. In addition to the CCD, a CMOS structure element has recently been actively published and can be used as a matter of course. In particular, some of the elements themselves have inter-frame difference calculation and binarization functions, and it is preferable to use these elements.
[0052]
A control device 114 is connected to the image sensor 115. In other words, the imaging device 111 is connected to the control device 114. The control device 114 controls the entire FG sensor 101. The control device 114 is typically installed separately from the imaging device 111, but may be configured integrally. In this way, the apparatus can be miniaturized. The control device 114 is typically a computer such as a personal computer. In addition, an image processing device 117 that acquires an image of a pattern imaged by the imaging device 111 is incorporated in the control device 114.
[0053]
Further, a height calculation unit 118 that calculates the height of the object 103 as an object by trigonometry based on the pattern image and the reference image captured by the imaging device 111 is incorporated in the control device 114. Here, the reference image and the pattern image are images picked up by, for example, the image pickup device 111, and include information on the positions of the reference image and the pattern image on the image pickup device 115 (or the imaging plane 115 ′). It is a concept. That is, the reference image and the pattern image are images of the pattern 110 a formed by the projection of the bright spot projector 110. Here, the reference image is an image of the pattern 110a when the object 103 does not exist on the plane 102, and the pattern image is an image of the pattern 10a when the object 103 exists on the plane 102. That is, the reference image is an image indicating the standard position of each bright spot 110b of the pattern 110a. The reference image may be stored in the image processing apparatus 117 in advance. Here, for example, the reference image may be stored not in the form of a so-called image but in the form of position information such as coordinates regarding the position of each bright spot 110b. In this way, when detecting the movement amount of the bright spot based on a pattern image and a reference image, which will be described later, for example, it is only necessary to compare the coordinates and direction of the bright spot, so the processing becomes simple.
[0054]
The imaging device 111 may include a filter 111b that attenuates light having a wavelength other than the peripheral portion of the wavelength of the laser light beam L1 generated by the light beam generation unit 105 (see FIG. 10) described later. The filter 111b is typically an optical filter such as an interference filter, and may be disposed on the optical axis of the imaging lens 111a. In this way, the imaging device 111 can reduce the influence of disturbance light because the light intensity of the pattern 110a projected from the bright spot projection device 110 among the light received by the imaging device 115 is relatively increased. The laser beam L1 generated by the beam generator 105 is typically an infrared laser beam. Further, the laser beam L1 may be irradiated continuously or intermittently. When irradiating intermittently, imaging by the imaging device 111 is performed in synchronization with the timing of irradiation.
[0055]
Further, the FG sensor 101 may be configured to perform modulation in order to distinguish it from disturbance light when the imaging device 111 captures the pattern 110a. The modulation is, for example, an operation in which light emission (irradiation) stop of the laser beam L1 by the beam generation unit 105 is periodically repeated. In this case, the light emission of the laser beam L1 may be stopped, for example, by stopping the light emission of the light source or by rotating the light shielding plate or the slit. In this case, the influence of disturbance light can be remarkably reduced by taking out a light reception signal synchronized with this modulation. Further, in addition to the above-mentioned modulation, the output of the laser beam L1 may be changed depending on the intensity of disturbance light. The image processing apparatus 117 may generate a signal obtained by subtracting the light reception signal when the laser light beam L1 is not irradiated from the light reception signal when the laser light beam L1 is irradiated. Thereby, the influence of disturbance light can be reduced. Further, the FG sensor 101 may be configured to perform a modulation operation a plurality of times and obtain an average output signal as acquired data, that is, a pattern image, in order to ensure reliability.
[0056]
Here, the operation of the FG sensor 101 will be described with reference to FIG. First, the concept of measuring the height of the object 103 will be described. The pattern 110 a projected onto the plane 102 by the bright spot projection device 110 is blocked by the object 103 and does not reach the plane 102 in a portion where the object 103 exists. Here, if the object 103 exists, the bright spot 110 b to be projected onto the point 102 a on the plane 102 is projected onto the point 103 a on the object 103. Since the bright spot 110b has moved from the point 102a to the point 103a and the imaging lens 111a and the bright spot projector 110 are separated by a distance d (base length d), on the imaging plane 115 ′, The point to be imaged at the point 102a ′ (x, y) is imaged at the point 103a ′ (x, y + δ). That is, when the object 103 does not exist and when the object 103 exists, the image of the bright spot 110b moves by a distance δ in the y-axis direction.
[0057]
For example, as shown in FIG. 8, the image of the bright spot 110b imaged on the imaging surface 115 ′ of the image sensor 115 is moved in the y-axis direction by δ by the object 103 having a height. .
[0058]
The FG sensor 101 can specify the position of the point 103a on the object 103 three-dimensionally by measuring this δ. That is, the height of the point 103a is known. In this way, by measuring the difference between a point that should be imaged on the imaging plane 115 ′ if the object 103 is not present and the actual imaging position on the imaging plane 115 ′, The height distribution of the object 103, in other words, a three-dimensional shape can be measured. Alternatively, the three-dimensional coordinates of the object 103 can be measured. Further, if the pitch of the pattern 110a, that is, the pitch of the bright spot 110b is made fine enough that the correspondence between the bright spots 110b is not unknown, the height distribution of the object 103 can be measured in detail.
[0059]
Here, the height calculation by the height calculation unit 118 will be described. The height calculation unit 118 reads the pattern image and the reference image, and measures the movement amount δ of the image of the bright spot 110b. To measure the movement amount δ, first, a difference image between a pattern image and a reference image is created. Then, the movement amount δ of the position of the corresponding bright spot image is measured from the difference image. The amount of movement δ can be obtained by, for example, counting the number of pixels (the number of pixels moved) where the position of the image of the bright spot 110b has moved. In the above description, the difference image is created. However, the reference image is stored in the form of the position information of each bright spot 110b, and the position information of each bright spot 110b of the pattern image and the reference image are stored. The amount of movement δ may be measured by comparing the position information of the bright spot 110b. In this way, the process can be simplified because it is not necessary to generate a difference image. The height calculator 118 calculates the height of the object 3 by trigonometry based on the movement amount δ. The calculation of the height of the object 103 by trigonometry will be described with reference to FIG.
[0060]
FIG. 9 is a side view of the relationship between the imaging device 111, the bright spot projection device 110, the object 103, and the plane 102 in the X-axis direction (see FIG. 7). Here, the case where the height of the object 103 is Z1 will be described. The center of the bright spot projector 110 (the center of the pattern light source) and the center of the imaging lens 111a are arranged in parallel to the plane 102 and separated by a distance d, and the imaging surface 115 ′ (imaging) is separated from the imaging lens 111a. The distance to the element 115) is l (equivalent to the focal point of the imaging lens 111a), the distance from the imaging lens 111a to the plane 102 is h, and the height of the point 103a of the object 103 from the plane 102 is Z1. It is. As a result of placing the object 103 on the plane 102, it is assumed that the point 102a ′ on the imaging plane 115 ′ has moved to the point 103a ′ separated by δ.
[0061]
If the point where the line connecting the center of the imaging lens 111a and the point 103a intersects the plane 102 in the figure is 102a ″, the distance D between the point 102a and the point 102a ″ is the triangle 103a′-102a′-111a. If attention is paid to the triangle 102a ″ −102a−111a, D = δ · h / l, and if attention is paid to the triangle 111a−110−103a and the triangle 102a ″ −102a−103a, D = (d · Z1) / (H-Z1). When Z1 is obtained from both equations, the following equation is obtained.
Z1 = (h ² .Delta.) / (D.l + h.delta) (1)
As described above, the height of the object 103 can be calculated.
[0062]
Furthermore, the height of the object 103 calculated by the height calculation unit 118 may be a moving average value or a period average value of a height calculated a certain number of times in the past or calculated within a certain period in the past. In this way, random noise and sudden noise caused by sunlight flickering from a window can be reduced, and the reliability of the calculated height of the object 103 is improved.
[0063]
As described above, the FG sensor 101 captures the pattern 110a formed by the projection of the bright spot projection device 110 in the target region by the imaging device 111, and triangulation based on the captured pattern image and the reference image. Thus, the height of the object is calculated by the height calculation unit 118, so that the height of the object can be measured. Further, since the FG sensor 101 can measure the height of the target at a plurality of points in the target area, it can measure the distribution of the height of the target. Further, by measuring the height distribution at, for example, a constant time interval, it is possible to measure the temporal change of the height distribution.
[0064]
Further, a bright spot projector 110 suitable for the FG sensor 101 will be described with reference to a schematic perspective view of FIG. The bright spot projection device 110 includes a light beam generation unit 105 as a light beam generation unit that generates a coherent light beam, and a fiber grating 120 (hereinafter simply referred to as a grating 120). The coherent beam is typically an infrared laser. The light beam generation unit 105 is configured to generate a parallel light beam. The light flux generation unit 105 is typically a semiconductor laser device including a collimator lens (not shown), and the generated parallel light flux is a laser light flux L1. The laser light beam L1 is a light beam having a substantially circular cross section. Here, the parallel light flux only needs to be substantially parallel, and includes a nearly parallel light flux.
[0065]
Here, the description will be given of the case where the grating 120 is arranged in parallel to the plane 102 (perpendicular to the Z axis). Laser light L1 is incident on the grating 120 in the Z-axis direction. Then, the laser beam L1 is condensed in a plane having the lens effect by each optical fiber 121, and then spreads as a diverging wave, interferes, and the pattern 110a is projected onto the plane 102 which is a projection plane. The Note that the arrangement of the grating 120 in parallel with the plane 102 means, for example, that the plane including the axis of each optical fiber 121 of the FG element 122 constituting the grating 120 and the plane 102 are parallel.
[0066]
The grating 120 includes two FG elements 122. In the present embodiment, the planes of the FG elements 122 are parallel to each other. Hereinafter, the plane of each FG element 122 is referred to as an element plane. In the present embodiment, the axes of the optical fibers 121 of the two FG elements 122 are substantially orthogonal to each other.
[0067]
The FG element 122 is configured by arranging, for example, several tens to several hundreds of optical fibers 121 having a diameter of several tens of microns and a length of about 10 mm in parallel in a sheet shape. Further, the two FG elements 122 may be arranged in contact with each other, or may be arranged at a distance from each other in the normal direction of the element plane. In this case, the distance between the two FG elements 122 is set so as not to interfere with the projection of the pattern 110a. The laser beam L1 is typically incident perpendicular to the element plane of the grating 110.
[0068]
As described above, since the grating 120 including the two FG elements 122 serves as an optical system, the bright spot projector 110 can reduce the size of the optical housing without requiring a complicated optical system. . Further, by using the grating 120, the bright spot projector 110 can project a plurality of bright spots 110b on the plane 102 as a pattern 110a with a simple configuration.
[0069]
In the above description, the pattern is described as a plurality of bright spots, but may be a plurality of bright lines. That is, the height of the object may be measured using a light cutting method. In this case, instead of the bright spot projection device 110, a bright line projection device 210 as a projection means for projecting bright lines is provided in the target area. The number of bright lines projected by the bright line projector 210 is typically plural, but may be one. Hereinafter, a case where there are a plurality of bright lines will be described. Hereinafter, the case where the optical cutting method is used for the FG sensor 101 will be described as the FG sensor 101 ′.
[0070]
The FG sensor 101 ′ will be described with reference to the schematic conceptual diagram of FIG. The bright line projection device 210 projects a plurality of bright lines 210b on the plane 102 in parallel. The imaging device 111 images the object 103 and the plane 102 on which the pattern 210 a is projected by the bright line projection device 210. A plurality of bright lines 210b are projected at equal intervals. The plurality of bright lines 210b forms a pattern 210a. Further, the direction of the bright line 210b and the base line direction of the trigonometric method are substantially perpendicular. That is, the direction of the bright line 210b is perpendicular to the y axis. In addition, although there are a plurality of bright lines here, there may be one. In this case, the FG sensor 101 ′ can be configured more simply.
[0071]
Here, the concept of measuring the height of the object 103 using the light cutting method will be described. The pattern 210 a projected onto the plane 102 by the bright line projection device 210 is blocked by the object 103 and does not reach the plane 102 in a portion where the object 103 exists. If the object 103 does not exist here, the bright line to be projected to the point 102 a on the plane 102 is projected to the point 103 a on the object 103. Since the bright line has moved from the point 102a to the point 103a and the imaging lens 111a and the bright line projection device 210 are separated from each other by a distance d (base line length d), the point 102a ′ is formed on the imaging plane 115 ′. An image to be imaged at (x, y) is imaged at a point 103a ′ (x, y + δ). That is, the bright point moves by a distance δ in the y-axis direction between the time when the object 103 does not exist and the time when the object 103 exists.
[0072]
For example, as shown in FIG. 12, the image of the bright line 210 b formed on the imaging plane 115 ′ of the image sensor 115 moves in the y-axis direction by δ by the object 103 having a height. Similar to the FG sensor 101, by measuring this δ, the position of the point 103a on the object 103 can be specified three-dimensionally. That is, the height of the point 103a is known. Further, if the pitch of the pattern 210a, that is, the pitch of the bright line 210b is made fine enough that the correspondence relationship of the bright line 210b is not unknown, the height distribution of the object 103 can be measured in detail. Further, the calculation of the height by the height calculation unit 118 is the same as the description of FIG.
[0073]
As described above, the FG sensor 101 ′ can measure the movement of an arbitrary point of the bright line as compared to the case where the pattern is a bright spot by measuring the movement of the bright line by setting the pattern as a plurality of bright lines, The continuous shape in the bright line direction can be recognized. In other words, the measurement resolution in the X-axis direction in the drawing can be improved.
[0074]
With reference to the schematic perspective view of FIG. 13, a bright line projection apparatus 210 suitable for the FG sensor 101 ′ will be described. The bright line projection apparatus 210 includes the light beam generation unit 105 described above with reference to FIG. 10 and a fiber grating 220 (hereinafter simply referred to as the grating 220).
[0075]
Here, the case where the grating 220 is arranged parallel to the plane 102 (perpendicular to the Z axis) will be described. Laser light L1 is incident on the grating 220 in the Z-axis direction. Then, the laser light L1 is collected in a plane having the lens effect by each optical fiber, then spreads as a diverging wave, interferes, and the pattern 210a is projected onto the plane 102 which is the projection plane. . Note that the arrangement of the grating 220 parallel to the plane 102 means, for example, that the plane including the axis of each optical fiber 221 of the first FG element 222 constituting the grating 220 and the plane 102 are parallel, as will be described later with reference to FIG. It is arranged so that it becomes.
[0076]
The grating 220 will be described with reference to the schematic diagram of FIG. (A) is a perspective view, (b) is a front view. The grating 220 includes a plurality of optical fibers 221, a first fiber grating element 222 (hereinafter referred to as a first FG element 222) in which the axes of the optical fibers 221 are arranged in parallel and in a plane toward the first direction v1, and a plurality of optical fibers 221. A second fiber grating element 223 (hereinafter referred to as a second FG element 223) in which the optical fibers 221 are arranged in parallel and in a plane with the axis of each optical fiber 221 in a second direction v2 different from the first direction v1; A third fiber grating element 224 (hereinafter referred to as a third FG) in which the optical fibers 221 are arranged in parallel and in a plane in the third direction v3 different from the first direction v1 and the second direction v2 with the axes of the optical fibers 221 being arranged in parallel. Element 224). In the present embodiment, the planes of the FG elements 222, 223, and 224 are parallel to each other. Here, in order to identify each FG element, it calls a 1st FG element, a 2nd FG element, and a 3rd FG element. In the present embodiment, the first FG element, the second FG element, and the third FG element are overlaid in this order. However, other orders, for example, the first FG element, the third FG element, and the second FG element may be overlapped in this order. Hereinafter, the plane of each FG element 222, 223, 224 is referred to as an element plane.
[0077]
The first FG element 222, the second FG element 223, and the third FG element 224 are similar to the FG element 122 described above. In the figure, the FG elements 222, 223, and 224 are arranged in contact with each other, but may be arranged with a distance in the normal direction of the element plane. In this case, the distance between the FG elements 222, 223, and 224 is set so as not to interfere with the projection of the pattern 210a.
[0078]
The first FG element 222, the second FG element 223, and the third FG element 224 are overlapped to constitute the grating 220. Note that the superposition is performed so that the element planes of the FG elements 222, 223, and 224 are substantially parallel to each other. In other words, in the present embodiment, the grating 220 is superposed in the order of the first FG element 222, the second FG element 223, and the third FG element 224 so that the respective element planes are parallel. The grating 220 is configured to transmit the laser light beam L1 generated by the light beam generation unit 105. Here, the laser beam L1 is transmitted through the first FG element 222, the second FG element 223, and the third FG element 224 in this order. The laser beam L1 is typically incident perpendicular to the element plane of the grating 220 (first FG element 222).
[0079]
Furthermore, as shown in FIG. 14B, in the present embodiment, the first direction v1 and the second direction v2 are substantially orthogonal. Further, the third FG element 224 is overlapped by rotating the third direction v3 in a plane parallel to the element plane by a predetermined angle θ from the first direction v1. The predetermined angle θ will be described later with reference to FIG.
[0080]
Here, the predetermined angle θ will be described with reference to FIG. First, a description will be given of a change in the bright spot by giving a predetermined angle θ. In (a), as shown in (b), the case where the predetermined angle θ is θ1 will be described. (A) is a diagram showing a part of a pattern 210a ′ projected when the laser beam L1 is transmitted from the back side to the front side in the drawing of (b). In the drawing, for reference, θ1 is shown at about 10 °. First, attention is paid to the bright spots 251, 252, 253, 254, and 255 that are part of the pattern 210 a ′ projected when the predetermined angle θ is 0 °. When the predetermined angle θ1 is given to the third FG element 224, each of the bright spots is diffracted in the direction of the straight line 251a ′ forming the angle θ1 with respect to the straight line 251a that is the generation direction of each bright spot. Project bright spots. Further, if attention is paid to the bright spot 251, the bright spot 251 diffracts in the direction of the straight line 251 a ′ to project a new bright spot 251 ′.
[0081]
As a result, the diffraction direction of the bright spot changes depending on the predetermined angle θ. Depending on θ, for example, a plurality of bright line rows (hereinafter simply referred to as a plurality of bright lines) that are parallel and arranged at equal intervals, or a dense bright spot The array can be projected. In other words, by adjusting the predetermined angle θ to the third FG element 224, a plurality of bright lines can be easily projected.
[0082]
With reference to the schematic diagram of FIG. 16, an example in which a predetermined angle θ is adjusted to make a pattern a plurality of bright lines will be described. A bright line is formed by a plurality of bright spots gathering linearly. In addition, since the FG element has a diffraction efficiency that is nearly constant over low-order to high-order diffracted light, and the bright line is formed by a collection of a plurality of bright spots, the brightness of the central part of the bright line is high. However, even if it goes from the center to the edge of the bright line, it hardly changes. That is, bright lines with uniform brightness can be projected. In the case of a plurality of bright lines, the predetermined angle θ is 0.1 to 10 °, preferably 1 to 8 °, and most preferably about 5 °. Further, when θ = 85 °, a plurality of similar bright lines are obtained. However, in this case, the projected pattern is a pattern obtained by rotating (b) by 90 °.
[0083]
As described above, the bright line projection device 210 can project a plurality of bright line patterns 210a by transmitting the laser light beam L1 through the first FG element 222, the second FG element 223, and the third FG element 224. Can be configured. In addition, the bright line projection apparatus 210 requires a complicated optical system because the grating 220 including the first FG element 222, the second FG element 223, and the third FG element 224 that are superimposed is an optical system. The optical housing can be reduced in size without doing so. Furthermore, since it is configured in this way, a plurality of bright lines can be projected onto the plane 102 as a pattern 210a. Furthermore, since the bright lines are formed by a set of bright spots, a plurality of bright lines with uniform brightness can be projected. For this reason, there is an advantage in measuring the movement of the bright line as in the present embodiment.
[0084]
The bright line projection apparatus has been described in the case of the bright line projection apparatus 210 described above, but is not limited thereto. For example, the bright line projection apparatus is configured to project a plurality of bright lines as the pattern 210a using a cylindrical lens, a slit, or the like. Also good.
[0085]
FIG. 17 shows a bright line projector 310 as another example of the bright line projector. The bright line projector 310 has an optical element 311 formed of optical glass. The optical element 311 has a convex 311a portion having a substantially triangular cross section on the incident side of the light beam, and a cylindrical surface 311b formed at the front end portion of the convex portion 311a on the incident side of the light beam. The optical element 311 is typically a Powell lens disclosed in US Pat. No. 4,826,299. A luminous flux can be projected onto the target region by causing the laser beam L1 ′ having a diameter smaller than the radius of curvature of the cylindrical surface 311b to be incident on the cylindrical surface 311b of the optical element 311. Furthermore, a plurality of bright lines can be projected by disposing a diffraction element, for example, the above-described FG element on the target region side of the optical element 311. The bright line projection apparatus 310 can project a plurality of bright lines with uniform brightness by using such an optical element 311.
[0086]
Further, as shown in the schematic diagram of FIG. 18, the FG sensor 101 ′ scans the target area in the y-axis direction in the drawing at a sufficiently high speed compared to the movement of the target object. A plurality of pattern images projected at different positions may be captured. In this case, the bright line generating means is a bright line projector 210 ′ capable of scanning the projected bright line in a specific direction of the target area. In this case, a pattern image that is an image of the above-described pattern 210a (see FIG. 11) may be obtained by combining a plurality of pattern images thus captured. In other words, as shown in (b), by combining the bright line pattern images projected at different positions, the same pattern image as the pattern image of the target area onto which the plurality of bright lines, that is, the pattern 210a is projected, is generated. May be. More specifically, as shown in the figure, for example, pattern images acquired at times t1, t2, t3, and t4 are combined to generate a pattern image of a target region on which a plurality of bright lines are projected. That is, the number of times that the pattern image is acquired while the bright line is scanning in the target area is the number of bright line images on the combined pattern image. Note that the number of bright lines to be scanned is typically one.
[0087]
Here, an installation example of the FG sensor 101 will be described with reference to a schematic external view of FIG. The bright spot projection device 110 and the imaging device 111 are arranged above the bed 3. In the figure, the bright spot projection device 110 is disposed approximately above the head of the person 2, and the imaging device 111 is disposed approximately above the center of the bed 3. The bright spot projector 110 projects a pattern 110a on the bed 3. The angle of view of the imaging device 111 is set so that the entire bed 3 can be imaged. The control device 114 may be incorporated in the control unit 21 described with reference to FIG. By doing in this way, the structure of the fall prediction apparatus 1 can be simplified.
[0088]
In addition, the bright spot projector 110 is typically installed with its optical axis (projection direction of the laser beam) tilted with respect to the vertical direction of the target area as shown in the figure. In this way, the pattern 110a can be easily projected over a wide range. Further, for example, it is possible to easily install the imaging device 111 and the bright spot projection device 110 at a distance. In addition, the imaging device 111 is installed with the optical axis approximately parallel to the vertical direction of the target region. Here, as described above, the bright spot projector 110 is installed with its optical axis inclined with respect to the vertical direction of the target area, but may be installed in a direction substantially parallel to the vertical direction. . In other words, the optical axis may be installed in a direction approximately parallel to the optical axis of the imaging device 111.
[0089]
Furthermore, the imaging device 111 and the bright spot projection device 110 are installed so that the axis (baseline direction) connecting the imaging device 111 and the bright spot projection device 110 and the center line of the bed 3 are approximately parallel. Further, the imaging device 111 and the bright spot projection device 110 may be installed with a certain distance. By doing so, the distance d (baseline length d) described above with reference to FIG. 7 is increased, so that changes can be detected sensitively. The imaging device 111 and the bright spot projection device 110 may be installed by being attached to a stand, for example. This facilitates the installation of the FG sensor 101 (particularly, the imaging device 111 and the bright spot projection device 110). For example, the FG sensor 101 can be installed at a necessary place when necessary in a hospital or the like. The imaging device 111 and the bright spot projection device 110 may be attached to the ceiling. In this way, it is possible to easily fix the imaging device 111 and the bright spot projection device 110 more reliably. Although the FG sensor 101 has been described here, the FG sensor 101 ′ may be installed in the same manner.
[0090]
By using the FG sensor 101 as the three-dimensional sensor 10 as described above, the three-dimensional information in the target region can be accurately acquired. The three-dimensional sensor 10 is not limited to the FG sensor 101 described above, and may be anything that can acquire three-dimensional information of the target region. For example, a sensor using a moire, a sensor using a stereo camera, and a plurality of distance sensors A sensor using may be used.
[0091]
A sensor using moire can acquire three-dimensional information by, for example, imaging a moire fringe formed using two slits. By using moire, the height distribution in the fringe direction can be measured continuously, so that highly accurate three-dimensional information can be acquired. Moire is a rough striped pattern generated by the difference in spatial frequency between two regular intensity distributions. There is a moire of the sum caused by the sum of two intensity distributions and a moire of the product caused by the product. The former can be realized by a double-exposed photograph of the two regular distributions, and the latter records each regular distribution. Just look at the transparent images. Further, by using the information on the phase of the moire fringes, the movement of the person 2 can be detected with high accuracy.
[0092]
In addition, a sensor using a stereo camera acquires a stereo image by, for example, two CCD cameras, and searches for corresponding points on the stereo image. region Can be measured by trigonometry. That is, the three-dimensional information of the target area can be acquired. Since three-dimensional information is acquired based on a two-dimensional image, it is highly accurate.
[0093]
Furthermore, a sensor using a plurality of distance sensors can acquire three-dimensional information by installing a plurality of distance sensors corresponding to necessary measurement points and measuring the distances of the plurality of measurement points in the target region. it can. By using the distance sensor, three-dimensional information can be accurately acquired with little influence of ambient light. Further, since there is no need for image processing, a simple configuration can be achieved. The distance sensor to be used may basically be anything. For example, a trigonometric type such as an infrared sensor or an ultrasonic sensor may be used. (flight) type (measuring the distance by measuring the time when light is emitted and returning).
[0094]
As described above, the fall prediction device 1 according to the present embodiment can accurately predict the fall of the person 2 from the bed 3, so that, for example, it is possible to quickly know that an infant or an elderly person is likely to fall from the bed 3. Accidents caused by falling can be prevented. Further, since it is possible to detect that the person 2 has fallen, it is possible to respond quickly even if the person 2 has fallen. Moreover, since the fall prediction apparatus 1 can detect the respiration of the person 2, when an elderly person or a sick person falls into a critical situation, it becomes possible to realize a quick emergency response.
[0095]
In the above description, the target area is described as being on the bed 3, that is, having a height higher than the periphery, but may be the same height as the periphery. In other words, for example, the inside of a fence placed on the floor may be set as the target area. In such a case, since the area monitoring device can detect a movement to get over the fence, it can be used to monitor an infant in a place surrounded by the fence, for example. The area monitoring device can also detect, for example, a movement of an animal over a fence to escape, so that it can be used in a zoo, for example. Furthermore, in the above description, the case where the fence is provided in the target area having a height higher than the bed, that is, the surrounding area is described, but the fence may not be provided. For example, in a normal case, before the person falls from the bed, a large change in height such as getting up at the peripheral edge of the bed is detected, so that the fall of the person can be predicted. In other words, it is possible to detect a movement of the object going out of the target area.
[0096]
【The invention's effect】
As described above, according to the present invention, a three-dimensional sensor that acquires three-dimensional information in a target area and a height that detects a change in height in the target area based on the acquired three-dimensional information. Change detection means, position detection means for detecting the position of the object based on the detected height change, and motion monitoring means for monitoring the movement of the object to go out of the target area And when the detected position of the target object is a specific area within the target area, and the change in the height of the target object is equal to or greater than a predetermined amount. In addition, since it is configured to detect the movement of going out of the target area, it is possible not only to detect the movement of the target going out of the target area, but also to provide a simple area monitoring device.
[Brief description of the drawings]
FIG. 1 is a schematic external view of a fall prediction apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a fall prediction apparatus according to an embodiment of the present invention.
FIG. 3 is a schematic plan view for explaining a specific area on the bed in the case of FIG. 1;
FIG. 4 is a schematic diagram showing a respiratory waveform pattern used in the embodiment of the present invention.
FIG. 5 is a schematic diagram showing waveform patterns of normal and abnormal breathing in the case of FIG. 4;
6 is a diagram showing a table of disease names or disease locations corresponding to abnormal respiration waveform patterns in the case of FIG. 5;
FIG. 7 is a conceptual perspective view of an FG sensor according to an embodiment of the present invention.
8 is a schematic diagram for explaining an image of a pattern formed on an image forming surface in the case of FIG. 7; FIG.
FIG. 9 is a diagram for explaining calculation of the height of an object in the case of FIG.
10 is a schematic perspective view for explaining the bright spot projector in the case of FIG. 7. FIG.
FIG. 11 is a conceptual perspective view of an FG sensor using an optical cutting method according to an embodiment of the present invention.
12 is a diagram illustrating an image of a pattern in the case of FIG.
13 is a schematic perspective view for explaining the bright line projection apparatus in the case of FIG. 11. FIG.
14A is a perspective view, and FIG. 14B is a front view for explaining a grating in the case of FIG.
15A is a schematic diagram of a pattern, and FIG. 15B is a front view of the grating for explaining a pattern projected by the grating of FIG. 14; FIG.
16 is a schematic plan view showing a pattern projected by the grating of FIG.
FIG. 17 is a schematic perspective view showing another embodiment of the bright line projection apparatus in the case of FIG. 11;
18 is a diagram showing still another form of the bright line projector in the case of FIG. 11, (a) a schematic perspective view of an FG sensor, and (b) a schematic diagram for explaining a combination of pattern images.
FIG. 19 is a schematic external view showing an example in which an FG sensor according to an embodiment of the present invention is installed.
[Explanation of symbols]
1 Fall prediction device
2 people
3 beds
4 Bedding
6 fence
10 3D sensor
20 arithmetic unit
21 Control unit
22 Height change detector
23 Position detector
24 Fall prediction unit
25 State detector
31 Memory unit
38 Alarm system
101 FG sensor
101 'FG sensor (using optical cutting method)
102 plane
103 objects
105 Light flux generator
110 Bright spot projector
110a pattern
110b Bright spot
111 Imaging device
114 Control device
115 Image sensor
117 Image processing apparatus
118 Height calculator
120 grating
121 optical fiber
122 FG element
210 Bright line projector
210a pattern
210b Bright line
220 grating
221 optical fiber
222 1st FG element
223 second FG element
224 3rd FG element

Claims (4)

A three-dimensional sensor for acquiring three-dimensional information in the target area;
Height change detection means for detecting a change in the height of the object in the target area based on the acquired three-dimensional information;
Position detecting means for detecting the position of the object by detecting an area in the object area where the height has changed;
Movement monitoring means for monitoring movement of the object going out of the target area;
The motion monitoring means includes a position of the object detected by the position detecting means in a specific area within the target area, and a height of the object detected by the height change detecting means. The object is determined to be a movement to go out of the target area when the change is equal to or greater than a predetermined amount ;
Further, the movement monitoring means is configured to detect the movement of the object, the position of the object is in the specific area, and the moving speed of the object immediately before reaching the position has a predetermined threshold value. Configured to detect a movement to go out of the target area when exceeded;
Area monitoring device. The movement monitoring means goes out of the target area when the change in the height of the object is a predetermined amount or more and the area of the height change of the predetermined amount or more is a predetermined area or more. Configured to detect movement to be attempted;
The region monitoring apparatus according to claim 1. The position detecting means determines an existing area where the object exists based on the detected height change, and includes an area including the determined existing area, and the existing area is limited to a predetermined range. An enlarged area is calculated, and the position of the object is detected in preference to the enlarged area;
The area monitoring apparatus according to claim 1 or 2 . The three-dimensional sensor includes a projection unit that projects a bright line or a plurality of bright spots on the target region;
Imaging means for imaging a pattern formed by the projection;
A height calculator that calculates the height of the object by trigonometry based on the captured pattern image and reference image;
Area monitoring device according to any one of claims 1 to 3.

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