JP5418387B2 - Position detection system, method, storage medium, and program - Google Patents

Description

  The present invention relates to a position detection system, method, storage medium, and program.

  As a technique for detecting the position of a moving body, there are methods using image processing, a wireless tag, and an optical tag. For example, in detection by image processing, a camera mounted on a movable autonomous robot obtains an image of the ceiling and specifies the current position, or estimates a wheelchair area from an image captured by the camera and compares it with a dictionary image It has been proposed to determine the presence or absence of a wheelchair. In addition, for detection using a wireless tag, it has been proposed that a wheelchair user can detect a wheelchair user who actually waits for an elevator at the elevator hall by holding the wireless tag. Furthermore, in the position detection of optical tags, it has been proposed to project the position of the moving body by projecting equilateral triangle or circular light onto the ceiling and detecting the vertex coordinates of the triangle and the long and short axes of the ellipse with the camera. ing.

JP 2007-257226 A Republished 2002-056251 JP 2007-45559 A JP 2005-17203 A Special table 2007-530978 gazette

  However, in the conventional technique for comparing with a dictionary image, for example, the detection accuracy generally depends on the type of wheelchair, the wear of the wheelchair user, the posture, size of the wheelchair, lighting change, occlusion, background change, etc. Therefore, it is practically difficult to determine whether or not there is a transportation auxiliary vehicle such as a wheelchair. Also, when detecting the exact position of three or more light spots from the image projected on the ceiling read by the camera, the projected figure is unclear, the resolution of the camera is low, etc. There is a problem that the position cannot be calculated. When a camera is mounted on a transport auxiliary vehicle, the camera size, power source, and delivery means for the detected position are problematic.

  The disclosed technology is a position detection system that detects the position of a moving body, and is an image of projection light that is mounted on the moving body from an image of the ceiling surface and is projected onto the ceiling surface from a vertically controlled light source An extraction unit that extracts an area; a calculation unit that calculates a centroid position of an image area of the projection light; and a position conversion unit that converts the centroid position into a position of the moving body on a floor surface. The

  The disclosed technology may be a position detection method performed by a computer, a computer-readable storage medium storing a program for causing a computer to execute the above-described means as a function, and the program.

  In the disclosed technique, the light projected onto the ceiling when the light source is in a vertical position is used, and therefore the position of the transport auxiliary vehicle can be accurately detected even when the outline of the projected light region is unclear.

It is a figure which shows the installation structural example. It is a figure which shows the structural example of the system which concerns on a present Example. It is a figure which shows the structural example of a light source. It is a figure which shows the structural example of a light source attitude | position control part. It is a figure which shows the other structural example of a light source attitude | position control part. It is a block diagram which shows the hardware constitutions of a position detection apparatus. It is a figure for demonstrating the method to extract the image area | region of the projection light by an image process part. It is a figure for demonstrating the processing flow in FIG. It is a figure for demonstrating the processing flow which detects the position of the conveyance auxiliary vehicle by a position detection part. It is a figure for demonstrating a calibration process. It is a figure for demonstrating the whole processing flow of a calibration process. It is a figure which shows the system configuration example which has the structure which detects a vertical attitude | position. It is a figure which shows the structural example of the vertical attitude | position detection part shown to FIG. 12 (A). It is a figure for demonstrating the processing flow in the structural example shown to FIG. 12 (B). It is a figure which shows the example of an output result by the processing flow of FIG. It is a figure which shows the system configuration example which added the movement / stationary determination part. It is a figure for demonstrating the processing flow in the system configuration example of FIG. It is a figure which shows the example of the matrix pattern of projection light. It is a figure which shows the pattern of pulsed light. It is a figure which shows the example of the light source for producing | generating the projection light of a convex shape pattern. It is a figure for demonstrating the method to obtain the front direction by an image process part. It is a figure which shows the structural example which notifies that projection light is shielded. It is a figure for demonstrating the method of re-searching when the area | region of a projection light is lost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an installation configuration example. As shown in FIG. 1, the projection light 4 projected on the ceiling surface 1 from the light source 3 mounted on the transport auxiliary vehicle 5 such as a stroller, a wheelchair, and a shopping cart moving on the floor surface 2 is directed upward. Take a picture with the attached camera 6.

  FIG. 2 is a diagram illustrating a configuration example of a system according to the present embodiment. A system 1000 shown in FIG. 2 irradiates a light source 3 that projects light onto the ceiling surface 1, a light source posture control unit 30 that holds the posture of the light source 3 vertically upward, and a projection surface 4 p such as the ceiling surface 1. A camera 6 for photographing the collected light, an image processing unit 7 for extracting a light irradiation region from the image, and a position detection unit 8 for acquiring the position of the transporter vehicle 5 on the floor 2 from the position of the irradiation region, Have

  The light source 3 is mounted on the transport auxiliary vehicle 5 by the light source attitude control unit 30, and the image processing unit 7 and the position detection unit 8 are realized by a computer that functions as the position detection device 100.

  FIG. 3 is a diagram illustrating a configuration example of a light source. In FIG. 3, the light source 3 includes a lens 3a, a light emitting element 3b, and a battery 3c. The light emitted from the light emitting element 3b passes through the lens 3a and is irradiated onto the projection surface 4p such as the ceiling surface 1. An LED, a laser, or the like is used for the light emitting element 3b. Moreover, when the light irradiated from the light emitting element 3b is infrared light, it becomes invisible and can be used without being conscious of the user.

  FIG. 4 is a diagram illustrating a configuration example of the light source attitude control unit. In the mechanical posture holding mechanism shown in FIG. 4, the light source posture control unit 30 is held by the two orthogonal rotation shafts 32 and the weight 33 so that the light emitting unit 31 is always upward. Therefore, the posture of the light source 3 is maintained so that the light emitted from the light source 3 is always vertically upward.

  FIG. 5 is a diagram illustrating another configuration example of the light source attitude control unit. The structural example of the light source attitude | position control part using drive mechanisms, such as a motor, is shown. As shown in FIG. 5A, the attitude control mechanism of the light source attitude control unit 30a includes an inclination sensor 34, a drive circuit 35, and a drive mechanism 36. A tilt sensor 34 attached to the light source 3 detects a deviation of the projection direction of the light source 3 from the vertical axis. When detecting the amount of deviation, the drive circuit 35 controls the drive mechanism 36 so that the deviation becomes zero. As the drive mechanism 36, for example, as shown in FIGS. 5B and 5C, a rotary motor 36a or a linear motor 36b is used. By preparing two driving mechanisms 36 and making the driving directions orthogonal to each other, it is possible to hold the light emitting unit so that it always faces upward.

  1 and 2, the camera 6 is installed upward so that the light projected onto the ceiling surface 1 can be photographed. In order to distinguish the projection light (infrared light) from the light source 3 and the ceiling illumination light, an optical filter that transmits only infrared light may be attached to the camera 6.

  The image processing unit 7 is a processing unit that extracts an image area of the projection light from the image of the ceiling surface 1 acquired by the camera 6.

  The position detection unit 8 is a processing unit that detects the position of the transport auxiliary vehicle 5 on the floor 2 from the image area of the projection light extracted by the image processing unit 7.

  The position detection apparatus 100 including the image processing unit 7 and the position detection unit 8 has a hardware configuration as shown in FIG. 6, for example. FIG. 6 is a block diagram illustrating a hardware configuration of the position detection device.

  In FIG. 6, a position detection device 100 is a terminal controlled by a computer, and includes a CPU (Central Processing Unit) 11, a memory unit 12, a display unit 13, an output unit 14, an input unit 15, and communication. The unit 16, the storage device 17, and the driver 18 are included, and are connected to the system bus B.

  The CPU 11 controls the position detection device 100 according to a program stored in the memory unit 12. The memory unit 12 uses a RAM (Random Access Memory), a ROM (Read-Only Memory), or the like, and is obtained by a program executed by the CPU 11, data necessary for processing by the CPU 11, and processing by the CPU 11. Stored data. A part of the memory unit 12 is allocated as a work area used for processing by the CPU 11.

  The display unit 13 displays various information required under the control of the CPU 11. The output unit 14 includes a printer or the like, and is used for outputting various types of information according to instructions from the user. The input unit 15 includes a mouse, a keyboard, and the like, and is used by a user to input various information necessary for the position detection apparatus 100 to perform processing. The communication unit 16 is a device that is connected to, for example, the Internet, a LAN (Local Area Network), and the like and controls communication with an external device. For example, a hard disk unit is used as the storage device 17 and stores data such as programs for executing various processes.

  A program that realizes processing performed by the position detection apparatus 100 is provided to the position detection apparatus 100 by a storage medium 19 such as a CD-ROM (Compact Disc Read-Only Memory). That is, when the storage medium 19 storing the program is set in the driver 18, the driver 18 reads the program from the storage medium 19, and the read program is installed in the storage device 17 via the system bus B. . When the program is activated, the CPU 11 starts its processing according to the program installed in the storage device 17. The medium for storing the program is not limited to a CD-ROM, and any medium that can be read by a computer may be used. The program for realizing the processing according to the present embodiment may be downloaded via the network by the communication unit 16 and installed in the storage device 17. Further, if the position detection device 100 is compatible with USB, it may be installed from an external storage device capable of USB connection. Further, if the position detection device 100 is compatible with a flash memory such as an SD card, it may be installed from such a memory card.

  Next, processing performed by the image processing unit 7 and the position detection unit 8 in the position detection apparatus 100 will be described with reference to FIGS. FIG. 7 is a diagram for explaining a method of extracting an image area of projection light by the image processing unit. FIG. 7 shows an example in which the background difference method is used to extract the image area of the projection light. In the background subtraction method, a background image acquired in advance and an image acquired by the camera 6 are compared, and a portion not shown in the background image is extracted. The background image is an image obtained by acquiring a state in which only the background is shown, and is stored in the storage area of the position detection device 100.

  FIG. 8 is a diagram for explaining the processing flow in FIG. In FIG. 8, the camera 6 acquires the image of the ceiling surface 1 and transfers it to the image processing unit 7 of the position detection device 100 (step S11). FIG. 7A shows an example of an image acquired by the camera 6. From this image example, the image processing unit 7 extracts an image area of the projection light 4 irradiated from the transport auxiliary vehicle 5 to the ceiling surface 1 (step S12). The background subtraction method is used to extract the image area of the projection light 4. In the background subtraction method, a background image acquired in advance and an image acquired by the camera 6 are compared, and a portion not shown in the background image is extracted. The background image is an image obtained by acquiring a state in which only the background is reflected, and is stored in the storage device 17 in advance.

The simplest background difference process is a method of comparing the luminance of pixels at the same position in each image and determining that the background is non-background when the luminance difference is a certain value or more. The luminance in the horizontal direction p and the vertical direction q of the background image I _B and the acquired image I _C is
I _B (p, q), I _C (p, q)
And At this time, if the luminance difference value is equal to or greater than the threshold value _ITH , it is determined that the background is not background.

If only the pixels determined to be non-background are extracted and a new image is generated, an object that is not shown in the background image can be extracted. The pixel (p, q) of the image _ID after the background difference processing is set as follows.

By considering the image region having a luminance of 255 as the projection light region by the above-described processing, for example, the projection region is extracted as illustrated in FIG.

Next, the image processing unit 7 obtains the barycentric position of the image area of the projection light 4 (step S13). When the number of pixels included in the projected light region R _D and N, the centroid position q _G of the center of gravity of the lateral p _G and vertical directions, are identified as shown in FIG. 7 (C), is given by: .

Using the center of gravity position p _G and longitudinal center of gravity q _G in the lateral direction obtained by the image processing unit 7, the position detecting unit 8 converts to a position of the transport assist vehicle 5 with the floor 2 (step S14).

FIG. 9 is a diagram for explaining a processing flow for detecting the position of the transport auxiliary vehicle by the position detection unit. In FIG. 9, the position detector 8 receives the center of gravity (p _G , q _G ) of the image area of the projection light from the image processor 7 (step S21).

As shown in FIG. 8, the position of the projection light on the screen generally does not represent the position on the floor surface 2. Therefore, it is necessary to convert the position in the image to a position on the floor surface 2. An arbitrary point S (p _S , q _S ) on the floor 2 and a point T (p _T , q _T ) in the image acquired by the camera 6 can be associated by applying projective transformation. The position detection unit 8 converts to the floor position (p _S , q _S ) using a conversion formula for performing projective conversion (step S22). The projective transformation will be described later.

The coefficients (a ₀ , b ₀ , c ₀ ), (a ₁ , b ₁ , c ₁ ), and (a ₂ , b ₂ , c ₂ ) are the same as those shown in FIGS. It is obtained by performing a calibration process, which will be described later, and stored in the storage area as coefficient information 8c.

The position detection unit 8 reads the coefficient information 8c from the storage area, and obtains coefficients (a ₀ , b ₀ , c ₀ ), (a ₁ , b ₁ , c ₁ ), (a ₂ , b ₂ , c _2). ), The position (p _G , q _G ) of the projection light detected by the image processing unit 7 can be converted into the position (p _S , q _S ) of the transport auxiliary vehicle 5 on the floor surface by Equation 4. it can. Then, the position detection unit 8 outputs the calculated position (p _S , q _S ) (step S23).

  Next, the calibration process will be described with reference to FIGS. FIG. 10 is a diagram for explaining the calibration process. FIG. 11 is a diagram for explaining the entire processing flow of the calibration processing.

  The overall flow of FIG. 11 will be described with reference to FIG. In FIG. 11, the camera 6 is installed so that the ceiling surface 1 can be photographed (step S31).

The calibration light sources 2a, 2b, 2c, and 2d are installed on the floor surface 2, and the coordinate position of each light source on the floor surface 2 is manually measured (step S32). As the positions of the calibration light sources 2a, 2b, 2c, and 2d on the floor 2 as shown in FIG. 10 (A), the coordinate positions (p _s1 , q _s1 ), (p _s2 , q _s2 ), (p _s3 , q _s3 ) and (p _s4 , q _s4 ) are measured.

  The calibration light sources 2 a, 2 b, 2 c, and 2 d are installed at, for example, the four corners of the floor surface 2. Light is output from the calibration light sources 2a, 2b, 2c, and 2d, and the four calibration projection lights 1a, 1b, 1c, and 1d projected on the ceiling surface 1 are photographed from the camera 6 (step S33).

The image photographed by the camera 6 is transferred to the image processing unit 6, and the image processing unit 6 uses the background difference method described above from the transferred image, and the position of the center of gravity of each of the calibration projection lights 1a, 1b, 1c, and 1d. Is obtained (step S34). As center positions of the calibration projection lights 1a, 1b, 1c, and 1d on the ceiling surface 1 as shown in FIG. 10B, (p _T1 , q _T1 ), (p _T2 , q _T2 ), (p _T3 , q _T3 ), and (p _T4 , q _T4 ) are calculated.

  The image processing unit 6 solves the following conversion formula,

Coefficients (a0, b0, c0), (a1, b1, c1), (a2, b2, c2) are obtained (step S35), and stored as coefficient information 8c in the storage area read by the position detector 7 (step S36). ).

[Light source shaking control]
Next, a configuration for improving the detection accuracy by controlling the shaking of the light source will be described. If the floor surface 2 is uneven, or if an operation such as suddenly accelerating or decelerating the transportation auxiliary vehicle 5 is performed, the shake of the light source will increase, and the exact position will only be obtained if the weight is attached and held in a vertical position. May not be detected. Therefore, the detection accuracy is improved by providing a vertical posture detection unit that detects that the posture of the light source has reached the vertical posture.

  FIG. 12 is a diagram illustrating a system configuration example having a configuration for detecting a vertical posture. In FIG. 12, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. Hereinafter, an outline of each process in the system configuration example shown in FIGS. 12A, 12B, and 12C will be described.

  In FIG. 12A, the transport auxiliary vehicle 5 has a configuration including a light source 3, a light source attitude control unit 30 of the light source 3, and a vertical attitude detection unit 50 that detects the vertical attitude of the light source 3. FIG. 13 is a diagram illustrating a configuration example of the vertical posture detection unit illustrated in FIG. In FIG. 13A, the vertical posture detection unit 50 includes a tilt sensor 34 and a light source control circuit 38. The tilt sensor 34 is attached to the side surface of the weight 33, for example, as shown in FIG.

  The tilt sensor 34 detects the attitude angle of the light source 3. The light source control circuit 38 controls light emission / non-light emission according to the posture angle. For example, when operating to emit light when the posture angle θ is within a certain range, light is emitted when the posture angle in the vertical direction is 0 degrees and the posture angle θ is smaller than the angle threshold value α degrees. It is good to control to do.

By providing the vertical posture detection unit 50 as described above, light is projected onto the ceiling surface 1 only when the light source 3 is in the vertical posture. Therefore, the exact position of the transport auxiliary vehicle 5 can be obtained only by following the processing flow of FIG. Can be detected.

  FIG. 12B shows a configuration example in which the output of the position detection unit 8 is controlled according to the detection result of the vertical posture detection unit 50. In FIG. 12B, the transporter vehicle 5 wirelessly transmits the light source 3, the light source attitude control unit 30 of the light source 3, the inclination sensor 34 that detects the attitude angle of the light source 3, and the attitude angle to the position detection device 100. And a wireless transmission unit 53 for transmission. In addition, the position detection device 100 includes an image processing unit 7, a position detection unit 8, a vertical posture detection unit 82, and a wireless reception unit 83. The vertical posture detection unit 82 is a processing unit that detects the vertical posture of the light source 3 based on the posture angle of the light source 3 received by the wireless reception unit 83.

  In the configuration example shown in FIG. 12B, first, the inclination angle of the light source is detected by the tilt sensor 34. The attitude angle is converted into a radio signal from the wireless transmission unit 53 and received by the wireless reception unit 83. The radio reception unit 83 converts the radio signal again into an attitude angle and inputs it to the vertical attitude detection unit 82. The vertical posture detection unit 82 controls the output of the position detection unit 8 according to the posture angle. For example, when the posture angle in the vertical direction is set to 0 degree, and the posture angle θ is smaller than the angle threshold value α degree, the position detection unit 8 may be controlled to output the position of the transport auxiliary vehicle 5.

By providing the vertical posture detection unit 82 as described above, the position is output only when the light source 3 is in the vertical posture, so that the accurate position of the transporter auxiliary vehicle 5 can be detected. A processing flow when the vertical posture detection unit 82 is added will be described with reference to FIG.

FIG. 14 is a diagram for explaining the processing flow in the configuration example shown in FIG. In FIG. 14, the camera 6 acquires the image of the ceiling surface 1 and transfers it to the image processing unit 7 of the position detection device 100 (step S41). The image processing unit 7 extracts the image area of the projection light 4 from the image of the ceiling surface 1 using the background subtraction method (step S42), and obtains the centroid position (p _G , q _G ) of the image area of the projection light 4. Calculate (step S43). The calculated barycentric position (p _G , q _G ) is provided to the position detection unit 8.

The position detection unit 8 converts the position of the center of gravity (p _G , q _G ) on the image into the position (p _S , q _S ) of the transport auxiliary vehicle 5 on the floor 2 (step S44), and the vertical designation detection unit 82. In the vertical designation detection unit 82, the attitude angle θ of the light source is

The position (p _S , q _S ) when satisfying is adopted (step S45).

  In the above description, the position detection unit 8 does not output a position when the light source 3 is not in a vertical posture. However, depending on the oscillation cycle of the light source 3, the interval between the detected positions may be increased, and there may be a case where the plurality of transport auxiliary vehicles 5 cannot be identified after the intersection, for example. In order to cope with such a case, only the position determined as the vertical direction by the vertical posture detection unit 82 may be adopted only when all the positions are output from the position detection unit 8 and an accurate flow line is obtained.

By applying such processing, even if a plurality of transporting auxiliary vehicles 5 are interlaced, each can be identified, and an accurate flow line can be detected.

  In FIG. 12B, the posture angle is transferred to the vertical posture detection unit 82 via the wireless transmission unit 53 and the wireless reception unit 83. However, as shown in FIG. The obtained position and posture angle are temporarily stored in the memory 81, and the information in the memory 54 is read out to the memory 84 in a time zone (for example, at night) when the transport auxiliary vehicle 5 is not used. You may process like.

FIG. 15 is a diagram showing an output result example according to the processing flow of FIG. The output result table T15 shown in FIG. 15 indicates the position (p _S , q _S ) on the floor surface 2 calculated by the position detection unit 8 in association with the time when the camera 6 acquires the image area of the projection light 4. The flag indicating adoption / non-adoption determined by the vertical posture detection unit 82. If Equation 8 is satisfied, “1” indicating adoption is set, and if Equation 8 is not satisfied, “0” indicating non-adoption is indicated.

  In the example of the output result table T15, the position at the time “10:32:15” (5.65, 2.13) and the position at the time “10:32:18” (5. 38, 3.35) can be used, and a more accurate flow line can be obtained.

[Static position detection]
Next, a method for detecting which product a shopper has focused on in a commercial facility or the like will be described. In an application for detecting the position of a shopper who is paying attention to a product, the detection accuracy during movement may be low if the detection accuracy of the stationary position is high. That is, when paying attention to a certain product or when purchasing, a high position detection accuracy is required to know the product that has been noticed. On the other hand, since it is considered that the product is not focused when moving, it is only necessary to obtain rough information such as which passage was used.

  If the floor surface 2 is uneven, or if an operation such as suddenly accelerating or decelerating the transport auxiliary vehicle 5 is performed, the shake of the light source 3 becomes large, and thus an accurate position may not be detected during movement. Therefore, by providing a movement / stillness determination unit, it is identified whether the transporter auxiliary vehicle 5 is in a moving state or a stationary state, and the position detection accuracy when it is determined as stationary is increased.

  FIG. 16 is a diagram illustrating a system configuration example to which a movement / stillness determination unit is added. In FIG. 16, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 16, the position detection device 100 further includes a movement / stillness determination unit 9. The movement / stillness determination unit 9 is in a stationary state when the position obtained by position detection converges to a certain value. I will look down.

A processing flow when the movement / stillness determination unit 9 is added will be described with reference to FIG. FIG. 17 is a diagram for explaining the processing flow in the system configuration example of FIG. In FIG. 17, the camera 6 acquires the image of the ceiling surface 1 and transfers it to the image processing unit 7 of the position detection device 100 (step S51). The image processing unit 7 extracts the image area of the projection light 4 from the image of the ceiling surface 1 using the background subtraction method (step S52), and obtains the barycentric position (p _G , q _G ) of the image area of the projection light 4. Calculate (step S53). The calculated barycentric position (p _G , q _G ) is provided to the position detection unit 8.

The position detection unit 8 converts the position of the center of gravity (p _G , q _G ) on the image into the position (p _S , q _S ) of the transport auxiliary vehicle 5 on the floor 2 (step S54). The converted positions (p _S , q _S ) are provided to the movement / stillness determination unit 9.

The movement / stillness determination unit 9 determines whether or not the difference from the previous sampling is equal to or less than a threshold value (step S55). The position of the transport auxiliary vehicle 5 obtained at the n-th sampling is defined as (p _S ⁽ⁿ⁾ , q _S ⁽ⁿ⁾ ). The difference d ⁽ⁿ⁾ between the positions of the ^(n-1) th sampling and the nth sampling is

It becomes. When the difference d ⁽ⁿ⁾ takes a value smaller than the threshold value d _th continuously N times, it is determined to be stationary. The movement / stillness determination unit 9 determines whether or not the difference d ⁽ⁿ⁾ is equal to or less than the threshold value _dth (step S56). Moving and still judgment unit 9, when the difference ^{d (n)} exceeds the threshold value _{d th,} and initializes the sampling number n to zero, the process returns to step S51, performs the above similar process (step S55-2). When the difference d ⁽ⁿ⁾ is less than or equal to the threshold value d _th , the movement / stillness determination unit 9 adds 1 to the sampling number n (step S56), and determines whether or not the sampling number n is equal to or greater than the predetermined number N. (Step S57). When the sampling number n is smaller than the predetermined number N, the process returns to step S51 and the same process as described above is performed.

  When the number of samplings n is equal to or greater than the predetermined number N, the movement / stillness determination unit 9 calculates a stationary position from the moving average (step S58), returns to step S51, and performs the same processing as described above.

  The processing in steps S55 to S57 is expressed by the following mathematical formula 11.

In addition, when the moving average of the positions obtained by the position detector 8 is calculated in a stationary state, the influence of minute shaking can be reduced, so that the detection accuracy can be further increased. In the processing in step S55, when the number of samples used in the moving average is M, the calculated position (p _avg , q _avg ) of the transport auxiliary vehicle 5 is

It is represented by

[Projection light pattern]
A mechanism for identifying the light source 3 will be described. FIG. 18 is a diagram illustrating an example of a matrix pattern of projection light. As shown in FIG. 18A, the light source 3 is identified by using the projection light 4 as a matrix pattern 18a and light emitting / not emitting light in each of the vertical and horizontal elements. For example, as shown in FIG. 18B, the matrix pattern is realized by inserting a filter 3f having a light / dark pattern after the lens 3a of the light source 3 and the like. The other components are the same as those in FIG. 3, so the same reference numerals are given and the description thereof is omitted.

  FIG. 19 is a diagram illustrating a pattern example of pulsed light. FIG. 19 shows an example in which light is output in pulses and the light source 3 is identified from the time interval between light emission and non-light emission. For example, FIG. 19A shows a pattern of pulsed light from the light source 3 with the identification number “1”, FIG. 19B shows a pattern of pulsed light from the light source 3 with the identification number “2”, FIG. 19C shows a pattern of pulsed light from the light source 3 with the identification number “3”. An example of identifying the light source 3 by turning the light source 3 on and off with a combination of long and short pulses is shown.

  A method of acquiring the front direction of the detection target by setting the projected light shape to be asymmetric in the front-rear direction (for example, the top of the convex is the front) will be described. FIG. 20 is a diagram illustrating an example of a light source for generating projection light having a convex pattern. FIG. 20A shows an example in which a bright and dark pattern is formed on the projection light 4 by the filter 3f provided in the light source 3, for example, as shown in FIG.

  When the image projected from the light source 3 of FIG. 20 onto the ceiling surface 1 is processed by the background subtraction method, the shape of the projection light 4 becomes, for example, as shown in FIG. FIG. 21 is a diagram for explaining a method of obtaining the front direction by the image processing unit. The image processing unit 7 selects a scanning direction for the light and dark pattern shown in FIG. For example, as shown in FIG. 21A, when a projected image is scanned with a straight line perpendicular to the scanning direction 21a, the straight line that first intersects the projected light region is L1, and the straight line that intersects last is L2. , LM is a straight line between L1 and L2. At this time, the number of pixels in the projection light region included in the region sandwiched between L1 and LM is I1, and the number of pixels in the projection light region included in the region sandwiched between L2 and LM is I2. When the scanning direction is rotated, the direction in which the difference between I1 and I2 is maximum is the front direction (FIG. 21B).

  A method for notifying the user that the projection light 4 projected from the light source is blocked will be described. FIG. 22 is a diagram illustrating a configuration example for notifying that the projection light is shielded. FIG. 22 shows an example in which a light emitting element 3 b and a light receiving element 3 g are mounted on the light source 3. When the light source 3 is shielded by a person or an article, a part of the projection light 4 is reflected by the shielding object and returns to the direction of the light emitting element 3b. Therefore, when the amount of reflected light received by the light receiving element 3g exceeds a certain level, it is determined that the projection light 4 is shielded, and an alarm is output. Further, when it is determined that the light is shielded, the battery may be processed so as to prevent the battery from being consumed by turning off the power supply to the light emitting element 3b.

  FIG. 23 is a diagram for explaining a re-searching method when the projected light region is lost. A predicted course area is set based on the moving direction vector immediately before the area of the projection light 4 on the ceiling surface 1 disappears. The moving direction vector V (n) is calculated using the current sampling and pre-sampling position vectors output from the position detection unit.

The expected course area 23e is, for example, a trapezoid. If the short side of the trapezoid is arranged so as to be perpendicular to the moving direction vector, the long side becomes the expected appearance position. The trapezoidal shape is given in advance. When the projection light 4 appears again from a part of the trapezoid, a vector ^R V connecting the position where the projection light disappears and the position ( ^R p _S , ^R q _S ) where it appears is calculated.

A vector ^{V (n),} when the direction of the ^R V are identical, projection light 4 which appeared is regarded as corresponding to the position carrying the auxiliary wheel which has lost in the _{^{(p S (n), q}} S (n)).

If the inner product is larger than the threshold value S _th as in the above equation, it is considered that both vectors match.

  As described above, in this embodiment, the light emission direction is always kept vertical, the inclination is corrected by the inclination sensor, and the position can be detected even with a weak light source by the background subtraction method.

  The present invention is not limited to the specifically disclosed embodiments, and various modifications and changes can be made without departing from the scope of the claims.

Regarding the above description, the following items are further disclosed.
(Appendix 1)
A position detection system for detecting the position of a moving object,
An extraction means for extracting an image area of projection light projected on the ceiling surface from a light source that is mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
Calculating means for calculating the position of the center of gravity of the image area of the projection light;
A position detection system comprising: position conversion means for converting the position of the center of gravity into the position of the movable body on the floor surface.
(Appendix 2)
The light source posture control means for controlling the light source vertically upward by means of a weight attached to the light source and holding the light source in a vertical posture and an inclination sensor for controlling the light source direction to be constant. Position detection system.
(Appendix 3)
Based on the posture angle of the light source, the light source has a vertical posture detection unit that detects that the light source has become a vertical posture, and when the vertical posture is detected, the light source emits light or the position conversion unit moves the device. The position detection system according to appendix 1, wherein the position of the body is output.
(Appendix 4)
The position detection system according to any one of appendices 1 to 3, further comprising a movement / stationary determination unit that determines whether the moving body is moving or stationary.
(Appendix 5)
The position detection system according to any one of appendices 1 to 4, wherein the projection light indicates a matrix pattern, and the light source is identified by emitting or not emitting each element in the vertical and horizontal rows.
(Appendix 6)
The position detection system according to any one of appendices 1 to 4, wherein the light source outputs light in a pulse shape, and identifies the light source from a time interval between light emission and non-light emission.
(Appendix 7)
The position detection system according to any one of appendices 1 to 4, wherein the projection light has an asymmetrical shape in front and back and indicates a front direction of the moving body.
(Appendix 8)
The light source has a projection light blocking detection means that determines that light is blocked when the amount of reflected light of a light receiving element provided in the light source is equal to or greater than a certain level, issues an alarm, or stops light emission from the light source. The position detection system according to any one of appendices 1 to 7, characterized by:
(Appendix 9)
A position detection method for detecting the position of a moving body, wherein a computer
An extraction procedure for extracting an image area of projection light projected on the ceiling surface from a light source mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
A calculation procedure for calculating the position of the center of gravity of the image area of the projection light;
A position detecting method for executing a position conversion procedure for converting the position of the center of gravity into the position of the moving body on the floor.
(Appendix 10)
A coefficient for converting from the coordinate position to the gravity center position is calculated from the coordinate position of the calibration light source installed on the floor and the gravity center position of the projection light projected from the calibration light source onto the ceiling surface. And further executing a coefficient calculation procedure for outputting to the storage area as coefficient information,
The position conversion procedure reads the coefficient information from the storage area, acquires the coefficient, and uses the coefficient to convert the position of the center of gravity to the position of the moving body on the floor surface. 10. The position detection method according to 9.
(Appendix 11)
A computer-readable storage medium storing a program that causes a computer to function as a position detection device that detects the position of a moving body,
An extraction procedure for extracting an image area of projection light projected on the ceiling surface from a light source mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
A calculation procedure for calculating the position of the center of gravity of the image area of the projection light;
A computer-readable storage medium that executes a position conversion procedure for converting the position of the center of gravity into the position of the moving body on the floor.
(Appendix 12)
A computer-executable program for causing a computer to function as a position detection device for detecting the position of a moving body,
An extraction procedure for extracting an image area of projection light projected on the ceiling surface from a light source mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
A calculation procedure for calculating the position of the center of gravity of the image area of the projection light;
A computer-executable program for executing a position conversion procedure for converting the position of the center of gravity into the position of the moving body on the floor.

DESCRIPTION OF SYMBOLS 1 Ceiling surface 2 Floor surface 3 Light source 3a Lens 3b Light emitting element 3c Battery 4 Projection light 4p Projection surface 5 Carrying auxiliary vehicle 6 Camera 7 Image processing part 8 Position detection part 8c Coefficient information 11 CPU
DESCRIPTION OF SYMBOLS 12 Memory unit 13 Display unit 14 Output unit 15 Input unit 16 Communication unit 17 Memory | storage device 18 Driver 19 Storage medium 30, 30a Light source attitude | position control part 31 Light emission part 32 Rotating shaft 33 Weight 34 Inclination sensor 36a Rotation motor 36b Direct drive motor 36 Drive Mechanism 37 Rotating shaft 50 Vertical posture detection unit 54 Memory 82 Vertical posture detection unit 83 Wireless reception unit 84 Memory 100 Position detection device 1000 System T15 Output result table

Claims (8)

A position detection system for detecting the position of a moving object,
An extraction means for extracting an image area of projection light projected on the ceiling surface from a light source that is mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
Calculating means for calculating the position of the center of gravity of the image area of the projection light;
A position detection system comprising: position conversion means for converting the position of the center of gravity into the position of the movable body on the floor surface.   2. A light source attitude control means for controlling the light source vertically upward by a weight attached to the light source and holding the light source in a vertical attitude and an inclination sensor for controlling the light source direction to be constant. The described position detection system.   Based on the posture angle of the light source, the light source has a vertical posture detection unit that detects that the light source has become a vertical posture, and when the vertical posture is detected, the light source emits light or the position conversion unit moves the device. The position detection system according to claim 1, wherein the position of the body is output.   The position detection system according to any one of claims 1 to 3, further comprising a movement / stationary determination unit that determines whether the moving body is moving or stationary.   5. The position detection system according to claim 1, wherein the projection light has an asymmetrical shape in front and back and indicates a front direction of the moving body. A position detection method for detecting the position of a moving body, wherein a computer
An extraction procedure for extracting an image area of projection light projected on the ceiling surface from a light source mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
A calculation procedure for calculating the position of the center of gravity of the image area of the projection light;
A position detecting method for executing a position conversion procedure for converting the position of the center of gravity into the position of the moving body on the floor. A computer-readable storage medium storing a program that causes a computer to function as a position detection device that detects the position of a moving body,
An extraction procedure for extracting an image area of projection light projected on the ceiling surface from a light source mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
A calculation procedure for calculating the position of the center of gravity of the image area of the projection light;
A computer-readable storage medium that executes a position conversion procedure for converting the position of the center of gravity into the position of the moving body on the floor. A computer-executable program for causing a computer to function as a position detection device for detecting the position of a moving body,
An extraction procedure for extracting an image area of projection light projected on the ceiling surface from a light source mounted on the moving body and vertically controlled from an image obtained by photographing the ceiling surface;
A calculation procedure for calculating the position of the center of gravity of the image area of the projection light;
A computer-executable program for executing a position conversion procedure for converting the position of the center of gravity into the position of the moving body on the floor.