JP2018132799A - Electronic blackboard system, electronic pen, display device and electronic pen position detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a position of an electronic pen without resulting in an increase in size and cost of the electronic pen.SOLUTION: Each of electronic pens 70 comprises a light emitting unit 73, a switch unit 74 for accepting a pressing operation, a first wireless communication unit 72, and a light emission control unit 71 for transmitting a first signal including identification information of the self-electronic pen from the first wireless communication unit 72 in response to the pressing operation to accept a light emission command signal including identification information of the self-electronic pen via the first wireless communication unit 72 and to output an optical pulse from the light emitting unit 73. A display device 60 comprises a second wireless communication unit 62, a camera unit 63, and a control unit 61 for receiving the first signal from each electronic pen via the second wireless communication unit 62 to transmit the light emission command signal from the second wireless communication unit 62. The control unit 61 causes each electronic pen to emit light at different timings and the camera unit 63 to image an optical pulse of each electronic pen, and acquires the position of each electronic pen on the display screen based on the captured image.SELECTED DRAWING: Figure 14

Description

  The present invention relates to an electronic blackboard system, an electronic pen, a display device, and an electronic pen position detection method.

There is provided an electronic blackboard system that uses a digital pen to indicate an arbitrary position on a display screen. In this type of electronic blackboard system, an infrared light pulse from an electronic pen is usually captured by a camera, and the captured image is analyzed to detect the position of the electronic pen. However, in this method, if drawing is performed simultaneously using a plurality of electronic pens, the infrared light pulses of the adjacent electronic pens cannot be identified, and therefore the position of each electronic pen cannot be detected accurately. There is a case.
Therefore, an electronic blackboard system has been proposed in which identification information (ID) is given to an electronic pen to identify the electronic pen. For example, Patent Document 1 discloses a remote instruction transmission / reception system as an example of an electronic blackboard system using an electronic pen with ID.

The remote instruction transmission / reception system described in Patent Literature 1 includes a plurality of electronic pens, a transmission / reception device, an information processing device, and a display device.
The transmission / reception device includes a wireless transmitter that performs wireless communication with each electronic pen, and a camera that captures light (infrared rays and visible light) from each electronic pen and a display screen of the display device. Each of the wireless transmitter and the camera is connected to the information processing apparatus via a communication cable.
The information processing apparatus causes a command including a recognition period including a plurality of time slots to be transmitted from the transmission / reception apparatus to each electronic pen.

The electronic pen includes a light emitting unit, a switch unit having a tact switch and a dial for setting attributes of the electronic pen, a receiving unit that receives the command from the wireless transmitter, and a light emitting unit that controls a light emitting operation of the light emitting unit. And a control unit.
The light emitting unit includes a first light source that emits infrared light and a second light source that emits visible light. The first light source is used to detect the position of the electronic pen on the display screen, and the second light source is used to transmit attribute information (ID or the like) of the electronic pen.
The light emission control unit operates in accordance with a command from the information processing apparatus. The light emission control unit determines a light emission form that defines a light emission color, a light emission timing, a light emission time, and the like according to the attribute of the electronic pen, and causes the light emission part to emit light in the light emission form during the tact switch ON period.

For example, in an electronic pen with the attribute A set, the first and second light sources emit light in the first and second time slots of the recognition period. In the electronic pen in which the attribute B is set, the first and second light sources emit light in the third and fourth time slots of the recognition period. Thus, the attribute of the electronic pen can be identified by changing the light emission form of the electronic pen according to the attribute.
When attribute A is set for a plurality of electronic pens, the electronic pens emit light simultaneously in synchronization with each other. Thereby, grouping of electronic pens is possible.

  The information processing apparatus analyzes the captured image from the camera, calculates the position of the electronic pen based on the infrared captured image output from the first light source, and captures the visible light image output from the second light source. The ID of the electronic pen is recognized based on the above. The information processing apparatus manages the position information of the electronic pen and the ID in association with each other, and displays an image indicating the trajectory of the electronic pen on the display device for each electronic pen.

JP 2011-239319 A

  However, in the remote instruction transmission / reception system described above, it is necessary to provide the electronic pen with a first light source used for detecting a position and a second light source used for transmitting attribute information (ID or the like). is there. Providing a plurality of light sources in the electronic pen in this way increases the size and cost of the electronic pen.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to detect the position of the electronic pen accurately without causing an increase in size and cost of the electronic pen, an electronic blackboard system, an electronic pen, a display device, and an electronic pen The object is to provide a pen position detection method.

In order to achieve the above object, according to one aspect of the present invention,
An electronic blackboard system comprising: a display device for displaying an image on a display screen; and a plurality of electronic pens each emitting a light pulse to indicate a position on the display screen,
Each of the electronic pens
A light emitting unit for outputting the light pulse;
A switch unit for receiving a pressing operation;
A first wireless communication unit that performs wireless communication with the display device;
In response to the pressing operation, a first signal including identification information of the electronic pen is transmitted from the first wireless communication unit, and after the transmission of the first signal, the first signal is transmitted via the first wireless communication unit. A light emission control unit that receives a light emission command signal including identification information of the electronic pen and outputs the light pulse from the light emission unit, and
The display device
A second wireless communication unit that performs wireless communication with each of the electronic pens;
A camera unit provided so that the entire display screen is in an imaging range, and imaging the light pulse of each of the electronic pens;
The first signal is received from each of the electronic pens via the second wireless communication unit, the identification information of each electronic pen is obtained from the first signal, and the electronic pen is identified for each electronic pen. A light emitting command signal including information is transmitted from the second wireless communication unit, and
The control unit controls the transmission timing of the light emission command signal so that the plurality of electronic pens emit light at different timings, causes the camera unit to capture an image of each light pulse of the electronic pen, and An electronic blackboard system is provided that acquires a position on the display screen indicated by each of the electronic pens based on an image.

According to another aspect of the invention,
An electronic pen used in combination with a display device that displays an image on a display screen,
A light emitting unit for outputting a light pulse;
A switch unit for receiving a pressing operation;
A wireless communication unit for performing wireless communication with the display device;
In response to the pressing operation, a first signal including identification information of the electronic pen is transmitted from the wireless communication unit, and light emission including the identification information is transmitted via the wireless communication unit after the transmission of the first signal. An electronic pen having a light emission control unit that receives a command signal and outputs the light pulse from the light emission unit is provided.

According to yet another aspect of the invention,
A display device that displays an image on the display screen, each used in combination with a plurality of electronic pens that emit light pulses to indicate a position on the display screen,
A wireless communication unit that performs wireless communication with each of the electronic pens;
A camera unit provided so that the entire display screen is in an imaging range, and imaging the light pulse of each of the electronic pens;
A control unit that receives identification information of the electronic pen from each of the electronic pens via the wireless communication unit, and transmits a light emission command signal including the identification information to the electronic pen from the wireless communication unit; Have
The control unit controls the transmission timing of the light emission command signal so that the plurality of electronic pens emit light at different timings, causes the camera unit to capture an image of each light pulse of the electronic pen, and A display device is provided that acquires a position on the display screen indicated by each of the electronic pens based on an image.

According to yet another aspect of the invention,
An electronic pen position detection method performed in an electronic blackboard system having a display device for displaying an image on a display screen, and a plurality of electronic pens each emitting a light pulse to indicate a position on the display screen. And
Each of the electronic pens wirelessly transmits a first signal including identification information of the electronic pen to the display device in response to a pressing operation.
The display device receives the first signal from each of the electronic pens, acquires identification information of each electronic pen, and the plurality of electronic pens emit light at different timings. Wirelessly transmitting a light emission command signal including the identification information of the electronic pen,
Each of the electronic pens emits the light pulse according to a light emission command signal including identification information of the own electronic pen among light emission command signals transmitted from the display device,
The display device causes the camera unit to capture the light pulse emitted by each of the electronic pens, and acquires a position on the display screen indicated by each of the electronic pens based on the captured image. A pen position detection method is provided.

  According to the present invention, the position of the electronic pen can be accurately detected without increasing the size and cost of the electronic pen.

It is a block diagram for demonstrating the structure of the electronic blackboard system by the 1st Embodiment of this invention. It is a schematic diagram which shows typically the external appearance of the electronic pen used with the electronic blackboard system shown in FIG. It is a block diagram which shows the structure of the part in connection with the signal processing function of the electronic pen used with the electronic blackboard system shown in FIG. It is a block diagram which shows the structure of the projector used with the electronic blackboard system shown in FIG. It is a flowchart which shows the process sequence at the time of drawing operation of an electronic pen. It is a flowchart which shows the process sequence of the projector at the time of drawing operation using an electronic pen. It is a figure for demonstrating a series of processes at the time of drawing operation performed between an electronic pen and a projector. It is a schematic diagram which shows typically the external appearance of the electronic pen used with the electronic blackboard system by the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the part in connection with the signal processing function of the electronic pen used with the electronic blackboard system by the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the projector used with the electronic blackboard system by the 2nd Embodiment of this invention. It is a flowchart which shows the process sequence at the time of drawing operation of an electronic pen. It is a flowchart which shows the process sequence of the projector at the time of drawing operation using an electronic pen. It is a figure for demonstrating a series of processes at the time of drawing operation performed between an electronic pen and a projector. It is a block diagram which shows the structure of the electronic blackboard system by other embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram for explaining the configuration of the electronic blackboard system according to the first embodiment of the present invention.
Referring to FIG. 1, the electronic blackboard system includes a projector 10 and a plurality of electronic pens 20. Although only two electronic pens 20 are shown in FIG. 1, three or more electronic pens 20 may be used.
The projector 10 projects an image such as an input video or a drawn video on a display screen 100 (for example, a whiteboard screen). The electronic pen 20 emits a light pulse from the tip to indicate a position on the display screen 100.

First, the configuration of the electronic pen 20 will be described in detail.
FIG. 2 is a schematic diagram schematically showing the appearance of the electronic pen 20. FIG. 3 is a block diagram illustrating a configuration of a part related to the signal processing function of the electronic pen 20. As shown in FIGS. 2 and 3, the electronic pen 20 includes a press switch 21, a two-axis sensor 22, a light emitting unit 23, an ID setting unit 24, an inclination sensor 25, a wireless communication unit 26, and a light emission control unit 27. The light emission control unit 27 is electrically connected to each of the push switch 21, the two-axis sensor 22, the light emission unit 23, the ID setting unit 24, the tilt sensor 25, and the wireless communication unit 26.

The light emitting unit 23 emits a light pulse in accordance with a light emission instruction signal from the light emission control unit 27. The emission wavelength of the light emitting unit 23 is appropriately set according to design specifications. Here, the light emitting unit 23 is configured to generate an infrared light pulse.
Identification information (ID) that can identify the electronic pen 20 is set in the ID setting unit 24. For example, the ID setting unit 24 is a dip switch (Dual In-line Package Switch) or the like. The wireless communication unit 26 is provided at the rear end of the electronic pen 20 and performs wireless communication with the projector 10.

The press switch 21 and the biaxial sensor 22 are integrally formed at the tip of the electronic pen 20. The biaxial sensor 22 detects the movement distance of the electronic pen 20 in the X-axis and Y-axis directions on the XY plane.
For example, the biaxial sensor 22 includes a ball (sphere) that is rotatably held at the tip of the electronic pen 20, a Y-direction rotary encoder, and an X-direction rotary encoder. The amount of rotation of the ball can be represented by the amount of rotation around each of the two axes orthogonal to each other. Here, the Y-direction rotary encoder detects the amount of rotation around one axis as the amount of movement in the Y-axis direction, and the X-direction rotary encoder detects the amount of rotation around the other axis as the amount of movement in the X-axis direction. . Based on the outputs of the Y-direction rotary encoder and the X-direction rotary encoder, the moving direction and moving amount of the electronic pen 20 in the XY plane can be acquired.

  In addition, since the user holds the electronic pen 20 by hand without being aware of the axial direction (Y axis and X axis) of the biaxial sensor 22, the axial direction (Y axis and X axis) of the biaxial sensor 22 depends on how the user holds the electronic pen 20. (Axis) changes. Therefore, in order to calculate the movement direction and amount of movement of the electronic pen on the display screen 100, the value indicated by the XY coordinate system of the biaxial sensor 22 is converted into the value indicated by the XY coordinate system on the display screen 100. There is a need to. In order to perform this coordinate conversion, the tilt sensor 25 is used.

The tilt sensor 25 detects the tilt in the Y-axis direction or the X-axis direction of the biaxial sensor 22 with respect to a predetermined direction in the in-plane direction of the plane including the Y axis and the X axis (XY plane) of the biaxial sensor 22. As the tilt sensor 25, for example, an attitude sensor using an acceleration sensor, a gyro sensor, or the like can be used.
For example, in a state where the electronic pen 20 is pressed against the display screen 100, the plane (XY plane) including the Y axis and the X axis of the biaxial sensor 22 and the display screen 100 constitute the same plane. In this case, if the predetermined direction is the Y-axis direction in the XY coordinate system of the display screen 100, the tilt sensor 25 is in the Y-axis direction of the XY coordinate system of the biaxial sensor 22 with respect to the Y-axis direction of the XY coordinate system of the display screen 100. Can be detected (rotation direction and rotation angle). Based on this inclination (rotation direction and rotation angle), coordinate conversion is performed so that the Y axis (or X axis) of the biaxial sensor 22 matches the Y axis (or X axis) of the display screen 100. Thereby, the moving direction and the moving amount of the electronic pen 20 on the display screen 100 can be calculated from the output value of the biaxial sensor 22. As described above, the tilt sensor 25 and the biaxial sensor 22 can detect the moving direction and the moving amount of the electronic pen 20 on the display screen 100.

  The push switch 21 has a structure in which the ball of the biaxial sensor 22 is used as a push button, and is switched between an ON state and an OFF state according to a pressing operation. A part of the ball protrudes from the tip of the electronic pen 20, and the push switch 21 is turned on by pushing the ball. The push switch 21 outputs an ON signal when in the ON state. The ball can be rotated even when it is pushed in.

The light emission control unit 27 controls the light emission operation of the light emitting unit 23. When the light emission control unit 27 receives the ON signal from the push switch 21, the light emission control unit 27 transmits a start signal including identification information (ID of the electronic pen) set in the ID setting unit 24 from the wireless communication unit 26 to the projector 10. . When the pressing switch 21 is turned from ON to OFF, the light emission control unit 27 transmits an end signal including the ID of the electronic pen from the wireless communication unit 26 to the projector 10.
When the light emission control unit 27 receives a light emission command signal including the ID of the electronic pen from the projector 10 via the wireless communication unit 26, the light emission control unit 27 supplies a light emission instruction signal to the light emission unit 23. The light emitting unit 23 emits an infrared light pulse only once in response to the light emission instruction signal.
Further, the light emission control unit 27 is based on the output of the biaxial sensor 22 and the output of the tilt sensor 25 at predetermined time intervals during the period in which the ON signal is received from the push switch 21 (ON signal reception period). The movement direction and movement amount of the electronic pen 20 on the display screen 100 are calculated. Then, the light emission control unit 27 transmits a drawing signal indicating the movement direction and the movement amount from the wireless communication unit 26 to the projector 10. The drawing signal includes the ID of the electronic pen.

Next, the configuration of the projector 10 will be described in detail.
FIG. 4 is a block diagram showing the configuration of the projector 10. Referring to FIG. 4, the projector 10 includes an information processing unit 11 including a CPU (Central Processing unit), a projection unit 12, a camera unit 13, a storage unit 14, a wireless communication unit 15, and an operation unit 16. The information processing unit 11 is electrically connected to each of the projection unit 12, the camera unit 13, the storage unit 14, the wireless communication unit 15, and the operation unit 16.

The operation unit 16 includes a plurality of operation keys (operation buttons). The user can operate the projector 10 and input necessary information using these operation keys. The storage unit 14 holds data and programs necessary for operating the projector 10 and includes a storage device such as a semiconductor memory or a hard disk drive (HDD). The storage unit 14 also includes a cache memory.
The projection unit 12 operates according to a control signal from the information processing unit 11 and projects an image such as an input video or a drawing video on the display screen 100. The wireless communication unit 15 performs wireless communication with each electronic pen 20. The display screen 100 may be a dedicated screen or a structure such as a wall.

The camera unit 13 is provided so that the entire display screen 100 is within the imaging range, and images the infrared light pulse from each electronic pen 20. As the camera unit 13, for example, an imaging element such as a complementary metal-oxide-semiconductor (CMOS) image sensor or a charge-coupled device (CCD) image sensor can be used.
The information processing unit 11 includes a light emission command signal generation unit 16, a drawing image generation unit 17, and an ID / coordinate information generation management unit 18.

The ID / coordinate information generation management unit 18 receives a start signal from the electronic pen 20 via the wireless communication unit 15, registers the ID included in the start signal in the cache memory, and emits a light command including the ID The generation request is supplied to the light emission command signal generation unit 16. When an ID included in the start signal is already registered in the cache memory when the start signal is received, the ID / coordinate information generation management unit 18 sends a light emission command generation request to the light emission command signal generation unit 16. Is not supplied.
In response to the light emission command generation request from the ID / coordinate information generation management unit 18, the light emission command signal generation unit 16 generates a light emission command signal including the ID included in the light emission command generation request, and the light emission command signal Is transmitted from the wireless communication unit 15. At this time, the wireless communication unit 15 may broadcast a light emission command signal.

The ID / coordinate information generation management unit 18 causes the camera unit 13 to capture an infrared light pulse emitted by the electronic pen 20 in response to the light emission command signal. Specifically, the ID / coordinate information generation management unit 18 causes the camera unit 13 to perform imaging after a predetermined time has elapsed from the transmission timing of the light emission command signal. Here, the predetermined time is a time required from when the light emission command signal is transmitted until the electronic pen 20 emits light. By appropriately setting the predetermined time, the camera unit 13 can be imaged in conjunction with the light emission operation of the electronic pen 20.
The ID / coordinate information generation management unit 18 acquires a captured image of the infrared light pulse from the camera unit 13 and acquires a position (initial position) of the electronic pen 20 on the display screen 100 based on the captured image. To do. For example, coordinate conversion information for converting the coordinate system of the camera unit 13 to the coordinate system of the projection unit 12 is stored in the storage unit 14, and the ID / coordinate information generation management unit 18 refers to the coordinate conversion information. Thus, the coordinate value of the captured image can be converted into the coordinate value on the display screen 100 (projection screen). The ID / coordinate information generation management unit 18 stores coordinate information indicating the initial position of the electronic pen on the display screen 100 in the cache memory for each electronic pen ID.

Further, the ID / coordinate information generation management unit 18 receives a drawing signal from the electronic pen 20 via the wireless communication unit 15. The ID / coordinate information generation management unit 18 acquires coordinate information corresponding to the ID included in the drawing signal from the cache memory, and coordinates indicating the current position of the electronic pen based on the coordinate information and the drawing signal. Get information. The ID / coordinate information generation management unit 18 supplies the coordinate information acquired from the cache memory (hereinafter referred to as previous coordinate information) and the coordinate information of the current position to the drawing image generation unit 17, and the cache memory information is currently stored. Update to the coordinate information of the position.
Further, the ID / coordinate information generation management unit 18 receives an end signal from the electronic pen 20 via the wireless communication unit 15. The ID / coordinate information generation management unit 18 acquires the ID of the electronic pen from the end signal, and deletes information regarding the acquired ID from the cache memory.

The drawing image generation unit 17 generates a drawing image indicating the locus of the electronic pen based on the previous coordinate information and the coordinate information of the current position supplied from the ID / coordinate information generation management unit 18. The drawing image generation unit 17 causes the projection unit 12 to project the generated drawing image.
In addition to the coordinate information, the ID / coordinate information generation management unit 18 associates the ID information with information necessary for drawing, such as pen setting information, such as line color, thickness, type (broken line, solid line, etc.). May be stored. In this case, the drawing image generation unit 17 may register different pen setting information between electronic pens and generate a drawing image according to the pen setting information.

Next, the operation of the electronic blackboard system of this embodiment will be described in detail.
First, the operation of the electronic pen 20 will be described in detail. FIG. 5 shows a processing procedure when the electronic pen 20 is drawn.
As shown in FIG. 5, the light emission control unit 27 determines whether or not the push switch 21 is turned on (step S10). When the press switch 21 is turned on, the light emission control unit 27 transmits a start signal including the ID of the electronic pen set in the ID setting unit 24 from the wireless communication unit 26 to the projector 10 (step S11). .

After transmitting the start signal, the light emission control unit 27 determines whether or not a light emission command signal including the ID of the electronic pen is received from the projector 10 via the wireless communication unit 26 (step S12). When the light emission command signal is received, the light emission control unit 27 outputs the infrared light pulse from the light emitting unit 23 only once in accordance with the light emission command signal (step S13).
Next, after a predetermined time has elapsed since the emission of the infrared light pulse (or the processing in step S15 described later), the light emission control unit 27 determines whether or not the push switch 21 is turned off (step S14).

When the pressing switch 21 remains ON, the light emission control unit 27 generates a drawing signal indicating the moving direction and moving amount of the electronic pen based on the outputs of the biaxial sensor 22 and the tilt sensor 25, and the self-electron A drawing signal including the pen ID is transmitted from the wireless communication unit 26 to the projector 10 (step S15). The processes in steps S14 to S15 are repeatedly executed.
When the press switch 21 is turned off, the light emission control unit 27 transmits an end signal including the ID of the electronic pen set in the ID setting unit 24 from the wireless communication unit 26 to the projector 10 (step S16). .

Next, the operation of the projector 10 will be described in detail. FIG. 6 shows a processing procedure of the projector 10 during the drawing operation of the electronic pen.
As illustrated in FIG. 6, the ID / coordinate information generation management unit 18 determines whether a start signal is received from the electronic pen 20 via the wireless communication unit 15 (step S20). When the start signal is received, the ID / coordinate information generation management unit 18 checks the cache memory in the storage unit 14 (step S21).

Next, the ID / coordinate information generation management unit 18 acquires the ID from the start signal, and determines whether or not the ID is registered in the cache memory (step S22).
If the ID is not registered in the cache memory, the ID / coordinate information generation management unit 18 registers the ID in the cache memory and supplies a light emission command generation request including the ID to the light emission command signal generation unit 16. Then, the light emission command signal generation unit 16 generates a light emission command signal including the ID in response to the light emission command generation request, and transmits the light emission command signal from the wireless communication unit 15 (step S23).
When the ID is registered in the cache memory, the ID / coordinate information generation management unit 18 determines that another electronic pen is using the ID, and ends the process for the start signal.

After transmitting the light emission command signal, the ID / coordinate information generation management unit 18 acquires a captured image of the infrared light pulse from the camera unit 13, analyzes the captured image, and acquires coordinate information indicating the initial position of the electronic pen. To do. Then, the ID / coordinate information generation management unit 18 registers the coordinate information of the initial position in the cache memory in association with the ID (step S24).
After registering the coordinate information of the initial position, the ID / coordinate information generation management unit 18 determines whether or not a drawing signal is received from the electronic pen 20 via the wireless communication unit 15 (step S25).

When the drawing signal is received, the ID / coordinate information generation management unit 18 acquires the ID from the drawing signal, acquires the coordinate information corresponding to the ID from the cache memory, the coordinate information, the drawing signal, The coordinate information indicating the current position of the electronic pen is acquired based on (Step S26). Then, the drawing image generation unit 17 causes the projection unit 12 to project a drawing image indicating the trajectory of the electronic pen based on the coordinate information acquired from the cache memory and the coordinate information of the current position, and the ID / coordinate information generation management unit 18 updates the cache memory information to the coordinate information of the current position (step S27).
When it is determined in step S25 that the drawing signal has not been received, or after executing the process of step S27, the ID / coordinate information generation management unit 18 sends an end signal from the electronic pen 20 via the wireless communication unit 15. Is determined (step S28). When the end signal is received, the ID / coordinate information generation management unit 18 acquires the ID from the end signal, and deletes information related to the ID from the cache memory (step S29). If the end signal has not been received, the process returns to step S25.

Next, the process of the electronic pen 20 shown in FIG. 5 and the process of the projector 10 shown in FIG. 6 will be described in association with each other.
FIG. 7 shows a series of processes at the time of a drawing operation performed between the electronic pen 20 and the projector 10.
When the user presses the tip of the electronic pen 20 to an arbitrary position on the display screen 100 and turns on the pressing switch 21, the electronic pen 20 wirelessly transmits a start signal including its own ID to the projector 10. (Step S30).

The projector 10 registers the ID included in the start signal in the cache memory (step S31), and wirelessly transmits a light emission command signal including the ID (step S32).
The electronic pen 20 emits an infrared light pulse in accordance with a light emission command signal including its own ID (step S33), and the projector 10 analyzes the captured image obtained by capturing the infrared light pulse to detect the initial position of the electronic pen 20. And the coordinate information is registered in the cache memory (step S34).
After emitting the infrared light pulse, the electronic pen 20 wirelessly transmits a drawing signal including its own ID to the projector 10 at a predetermined time interval (step S35). The projector 10 projects a drawing image based on the coordinate information (initial position coordinate information or previously updated coordinate information) registered in the cache memory and the drawing signal, and updates the cache memory (step S36).

When the user moves the tip of the electronic pen 20 away from the display screen 100 and turns off the pressing switch 21, the electronic pen 20 wirelessly transmits an end signal including its own ID to the projector 10 (step S37). .
The projector 10 deletes information related to the ID included in the end signal from the cache memory (step S38).

According to the electronic blackboard system of the present embodiment described above, the light emitting unit of the electronic pen 20 is composed of a single light source, so that the cost can be reduced compared to the electronic pen provided with a plurality of light sources described in Patent Document 1. And size reduction can be achieved.
In general, in an electronic blackboard system that draws information on the display screen using an electronic pen that emits infrared light pulses from the tip, the infrared light pulses from the electronic pen are imaged with a camera and the captured image is analyzed. To detect the position of the electronic pen. In this case, if drawing is performed simultaneously using a plurality of electronic pens, it is difficult to accurately detect the position of each electronic pen because the infrared light pulses of adjacent electronic pens cannot be identified.
On the other hand, according to the electronic blackboard system of the present embodiment, the projector 10 causes the plurality of electronic pens 20 to emit light at different timings and images infrared light pulses at the light emission timings of the respective electronic pens 20. Therefore, since the infrared light pulse can be imaged for each of the electronic pens 20 that are close to each other, the position of each electronic pen 20 can be accurately detected.

In addition, when the infrared light pulse from the electronic pen is imaged by the camera and the locus of the electronic pen is detected, the infrared light pulse may be blocked by the user's hand. It cannot be detected.
On the other hand, according to the electronic blackboard system of the present embodiment, the electronic pen 20 detects the moving direction and the moving amount on the display screen 100 with the biaxial sensor and the tilt sensor 25, and wirelessly communicates the detection result. It is configured to transmit from the unit 26 to the projector 10. As described above, the electronic pen 20 side detects the moving direction and the moving amount and wirelessly transmits, so that the trajectory of the electronic pen can be accurately detected.

(Second Embodiment)
As in the first embodiment, the electronic blackboard system according to the present embodiment includes a projector and a plurality of electronic pens, but the configuration of the projector and the electronic pen is different from that of the first embodiment.
FIG. 8 is a schematic diagram schematically showing the external appearance of the electronic pen 40. FIG. 9 is a block diagram illustrating a configuration of a portion related to the signal processing function of the electronic pen 40. As shown in FIGS. 8 and 9, the electronic pen 40 includes a push switch 41, a light emitting unit 43, an ID setting unit 44, a wireless communication unit 46, and a light emission control unit 47. The light emission control unit 47 is electrically connected to each of the push switch 41, the light emission unit 43, the ID setting unit 44, and the wireless communication unit 46.

The pressing switch 41, the light emitting unit 43, the ID setting unit 44, and the wireless communication unit 46 are basically the same as the pressing switch 21, the light emitting unit 23, the ID setting unit 24, and the wireless communication unit 26 described in the first embodiment. Therefore, detailed description thereof is omitted here.
The light emission control unit 47 controls the light emission operation of the light emitting unit 43. When the light emission control unit 47 receives the ON signal from the push switch 41, the light emission control unit 47 causes the wireless communication unit 46 to transmit an identification signal including the identification information (ID of the electronic pen) set to the ID setting unit 44 to the projector 30. .
Further, when the light emission control unit 47 receives a light emission command signal including the ID of the electronic pen from the projector 30 via the wireless communication unit 46, the light emission control unit 47 supplies a light emission instruction signal to the light emission unit 43. The light emitting unit 43 emits an infrared light pulse only once in response to the light emission instruction signal.

Next, the configuration of the projector 30 will be described in detail.
FIG. 10 is a block diagram showing the configuration of the projector 30. As shown in FIG. Referring to FIG. 9, the projector 30 includes an information processing unit 31, a projection unit 32, a camera unit 33, a storage unit 34, a wireless communication unit 35, and an operation unit 36 including a CPU. The information processing unit 31 is electrically connected to each of the projection unit 32, the camera unit 33, the storage unit 34, the wireless communication unit 35, and the operation unit 36.

The projection unit 32, camera unit 33, storage unit 34, wireless communication unit 35, and operation unit 36 are the projection unit 12, camera unit 13, storage unit 14, wireless communication unit 15 and operation unit 16 described in the first embodiment. Since these are basically the same, detailed description thereof is omitted here.
The information processing unit 31 includes a light emission command signal generation unit 36, a drawing image generation unit 37, and an ID / coordinate information generation management unit 38.

The ID / coordinate information generation management unit 38 receives an identification signal from the electronic pen 40 via the wireless communication unit 35, registers the ID included in the identification signal in the cache memory, and emits a light command including the ID The generation request is supplied to the light emission command signal generation unit 16. If the ID included in the identification signal is already registered in the cache memory when the identification signal is received, the ID / coordinate information generation management unit 38 issues a light emission command generation request to the light emission command signal generation unit 36. Is not supplied.
In response to the light emission command generation request from the ID / coordinate information generation management unit 38, the light emission command signal generation unit 36 generates a light emission command signal including the ID included in the light emission command generation request. Then, the light emission command signal generation unit 36 causes the wireless communication unit 35 to transmit a light emission command signal at a timing different from that of other electronic pens. At this time, the wireless communication unit 35 may broadcast a light emission command signal.

The ID / coordinate information generation management unit 38 causes the camera unit 33 to capture an infrared light pulse emitted by the electronic pen 40 in response to the light emission command signal. Specifically, the ID / coordinate information generation management unit 38 causes the camera unit 33 to perform imaging after a predetermined time has elapsed from the transmission timing of the light emission command signal. Here, the predetermined time is a time required from when the light emission command signal is transmitted until the electronic pen 40 emits light. By appropriately setting this predetermined time, the camera unit 33 can be imaged in conjunction with the light emission operation of the electronic pen 40.
Further, the ID / coordinate information generation management unit 38 acquires a captured image of the infrared light pulse from the camera unit 33, and acquires a position on the display screen 100 of the electronic pen 40 based on the captured image. The ID / coordinate information generation management unit 38 stores the coordinate information indicating the position of the electronic pen 40 in the cache memory in association with the ID of the electronic pen 40. The coordinate conversion information described in the first embodiment is also used for acquiring the coordinate information of the electronic pen 40.

When the coordinate information indicating the current position of the electronic pen 40 is acquired from the captured image, the ID / coordinate information generation management unit 38 determines whether the coordinate information associated with the ID of the electronic pen 40 is registered in the cache memory. judge. If the coordinate information is not registered, the ID / coordinate information generation management unit 38 registers the coordinate information indicating the current position of the electronic pen 40 in the cache memory as the coordinate information of the initial position. When coordinate information is registered, the ID / coordinate information generation management unit 38 supplies coordinate information indicating the current position of the electronic pen 40 and previous coordinate information registered in the cache memory to the drawing image generation unit 37. Then, the cache memory information is updated to the coordinate information of the current position.
The drawing image generation unit 37 generates a drawing image indicating the locus of the electronic pen 40 based on the previous coordinate information and the coordinate information of the current position supplied from the ID / coordinate information generation management unit 38. The drawing image generation unit 37 causes the projection unit 32 to project the generated drawing image.

Unlike the first embodiment, in this embodiment, the light emission command signal generation unit 36 repeatedly transmits a light emission command signal at a timing different from that of other electronic pens. Each time the light emission command signal is transmitted, the ID / coordinate information generation management unit 38 analyzes the captured image and determines whether or not the electronic pen 40 has emitted light according to the light emission command signal. When the electronic pen 40 is not emitting light, the ID / coordinate information generation management unit 38 determines that the push switch 41 of the electronic pen 40 has been turned off, and stops transmitting the light emission command signal from the light emission command signal generation unit 36. Let Then, the ID / coordinate information generation management unit 38 deletes information related to the ID of the electronic pen 40 from the cache memory.
The ID / coordinate information generation management unit 38 associates with the ID of the electronic pen, in addition to the coordinate information, pen setting information necessary for drawing, for example, line color, thickness, type (broken line, solid line, etc.) Such information may be stored. In this case, the drawing image generation unit 37 may register different pen setting information between electronic pens and generate a drawing image according to the pen setting information.

Next, the operation of the electronic blackboard system of this embodiment will be described in detail.
First, the operation of the electronic pen 40 will be described in detail. FIG. 11 shows a processing procedure when the electronic pen 40 is drawn.
As shown in FIG. 11, the light emission control unit 47 determines whether or not the push switch 41 is turned on (step S40). When the push switch 41 is turned on, the light emission control unit 47 transmits an identification signal including the ID of the electronic pen set in the ID setting unit 44 from the wireless communication unit 46 to the projector 30 (step S41). .

After transmitting the identification signal, the light emission control unit 47 determines whether or not a light emission command signal including the ID of the electronic pen is received from the projector 30 via the wireless communication unit 46 (step S42). When the light emission command signal is received, the light emission control unit 47 outputs the infrared light pulse from the light emission unit 43 only once according to the light emission command signal (step S43).
After the emission of the infrared light pulse, the light emission control unit 47 determines whether or not the push switch 41 is turned off (step S44).
When the push switch 41 remains ON, the light emission control unit 47 executes the process of step S42. Steps S42 to S44 are executed every predetermined time.
When the press switch 41 is turned off, the light emission control unit 47 ends the process at the time of the drawing operation of the electronic pen 40.

Next, the operation of the projector 30 will be described in detail. FIG. 12 shows a processing procedure of the projector 30 during the drawing operation of the electronic pen.
As illustrated in FIG. 12, the ID / coordinate information generation management unit 38 determines whether an identification signal is received from the electronic pen 20 via the wireless communication unit 35 (step S50). When the identification signal is received, the ID / coordinate information generation management unit 38 checks the cache memory of the storage unit 34 (step S51).

Next, the ID / coordinate information generation management unit 38 acquires the ID from the identification signal and determines whether or not the ID is registered in the cache memory (step S52). If the ID is registered in the cache memory, the ID / coordinate information generation management unit 38 determines that another electronic pen is using the ID, and ends the process for the identification signal.
If it is determined in step S52 that the ID is not registered, the ID / coordinate information generation management unit 38 registers the ID in the cache memory (step S53). Then, the light emission command signal generation unit 16 transmits a light emission command signal including the ID from the wireless communication unit 35 at a timing different from that of other electronic pens, and the ID / coordinate information generation management unit 38 causes the camera unit 33 to Then, imaging is performed (step S54).

Next, the ID / coordinate information generation management unit 38 acquires a captured image from the camera unit 33 and analyzes the captured image (step S55). Then, the ID / coordinate information generation management unit 38 determines whether or not the electronic pen 40 has emitted light (step S56).
If it is determined in step S56 that the electronic pen 40 has emitted light, the ID / coordinate information generation management unit 38 determines whether coordinate information regarding the ID of the electronic pen 40 is registered in the cache memory (step S57).

If it is determined in step S57 that the coordinate information is not registered in the cache memory, the ID / coordinate information generation management unit 38 acquires coordinate information indicating the current position of the electronic pen 40 from the captured image, and initializes the coordinate information. The position is registered in the cache memory in association with the ID of the electronic pen 40 (step S58). After registration of the initial position, the process of step S54 is executed.
If it is determined in step S57 that the coordinate information is registered in the cache memory, the drawn image generation unit 37 acquires coordinate information indicating the current position of the electronic pen 40 from the captured image. Then, based on the coordinate information of the current position and the previous coordinate information registered in the cache memory, the projected image 32 is projected by the projection unit 32 based on the coordinate information of the current position and the previous coordinate information registered in the cache memory. The information generation management unit 38 updates the cache memory information to the coordinate information of the current position (step S59).
If it is determined in step S56 that the electronic pen 40 is not emitting light, the ID / coordinate information generation management unit 38 deletes information related to the ID of the electronic pen 40 from the cache memory (step S60).

Next, the process of the electronic pen 40 shown in FIG. 11 and the process of the projector 30 shown in FIG. 12 will be described in association with each other.
FIG. 13 shows a series of processes during a drawing operation performed between the electronic pen 40 and the projector 30.
The user presses the tip of the electronic pen 40 to an arbitrary position on the display screen 100 to turn on the pressing switch 21 (step S70). The electronic pen 40 wirelessly transmits an identification signal including its own ID to the projector 30 (step S71).

The projector 30 registers the ID included in the identification signal in the cache memory (step S72), and wirelessly transmits a light emission command signal including the ID (step S73).
The electronic pen 40 emits an infrared light pulse in accordance with a light emission command signal including its own ID (step S74), and the projector 30 analyzes the captured image obtained by capturing the infrared light pulse to detect the initial position of the electronic pen 40. And the coordinate information is registered in the cache memory (step S75).
After registering the coordinate information, the projector 30 wirelessly transmits a light emission command signal (step S76), and the electronic pen 40 emits an infrared light pulse according to the light emission command signal (step S77). Then, the projector 30 analyzes the captured image obtained by capturing the infrared light pulse to detect the current position of the electronic pen 40, and draws the image based on the coordinate information and the previous coordinate information registered in the cache memory. Is projected (step S78). After projecting the drawn image, the projector 30 updates the cache memory (step S79).

The processes in steps S76 to S79 are repeatedly executed. Thereafter, the user releases the tip of the electronic pen 40 from the display screen 100 and turns off the push switch 41 (step S80).
After turning off the press switch 41, the projector 30 wirelessly transmits a light emission command signal (step S81). At this time, since the push switch 41 is OFF, the electronic pen 40 does not emit an infrared light pulse even if it receives a light emission command signal.
After wirelessly transmitting the light emission command signal in step S81, the projector 30 analyzes the captured image to detect non-light emission of the electronic pen 40, and recognizes that the push switch 41 is turned off (step S82). Then, the projector 30 deletes information regarding the ID of the electronic pen 40 from the cache memory (step S83).

Also in the electronic blackboard system of the present embodiment, the light emitting unit of the electronic pen 40 is composed of one light source as in the first embodiment, so that it is compared with the electronic pen having a plurality of light sources described in Patent Document 1. Thus, cost reduction and size reduction can be achieved.
Further, according to the electronic blackboard system of the present embodiment, the projector 30 causes the plurality of electronic pens 40 to emit light at different timings, and images infrared light pulses at the respective light emission timings of the electronic pens 40. Therefore, since the infrared light pulse can be imaged for each of the electronic pens 40 that are close to each other, the position of each electronic pen 40 can be accurately detected.

(Other embodiments)
FIG. 14 is a block diagram showing a configuration of an electronic blackboard system according to another embodiment of the present invention.
Referring to FIG. 14, the electronic blackboard system includes a display device 60 that displays an image on a display screen, and a plurality of electronic pens 70 that each emit a light pulse to indicate a position on the display screen.
The electronic pen 70 includes a light emitting unit 73 that outputs a light pulse, a switch unit 74 that receives a pressing operation, a first wireless communication unit 72 that performs wireless communication with the display device 60, and an electronic pen according to the pressing operation. The first signal including the identification information of the electronic pen is transmitted from the first wireless communication unit 72, and after the transmission of the first signal, the light emission command including the identification information of the own electronic pen via the first wireless communication unit 72 A light emission control unit 71 that receives a signal and outputs a light pulse from the light emission unit 73.

The display device 60 includes a second wireless communication unit 62 that performs wireless communication with each of the electronic pens 70, and a camera unit that is provided so that the entire display screen is within the imaging range, and that captures each light pulse of the electronic pen 70. 63, the first signal is received from each of the electronic pens 70 via the second wireless communication unit 62, the identification information of each electronic pen 70 is obtained from the first signal, and the electronic signal is obtained for each electronic pen 70. A control unit 61 that causes the second wireless communication unit 62 to transmit a light emission command signal including pen identification information.
The control unit 61 controls the transmission timing of the light emission command signal so that the plurality of electronic pens 70 emit light at different timings, causes each light pulse of the electronic pen 70 to be captured by the camera unit 62, and displays the captured image. Based on this, the position on the display screen indicated by each of the electronic pens 70 is acquired.

The electronic blackboard system of each embodiment described above is an example of the present invention. The present invention is not limited to the configuration described in each embodiment. In the configuration of each embodiment, improvements or changes that can be understood by those skilled in the art can be applied without departing from the spirit of the invention.
For example, in the second embodiment, when the pressing switch 41 is turned off, the electronic pen 40 may wirelessly transmit an end signal including its own ID to the projector 30. In this case, the projector 30 may delete the information regarding the ID from the cache memory according to the end signal.

In the other embodiments described above, a part or all of the configuration described in the first or second embodiment may be applied.
Generally, the electronic blackboard system includes a display type that performs an input operation on a display screen in which a display and a touch panel are integrated, and a projector type that performs an input operation on a projection screen. The present invention can be applied to both a display type and a projector type.

60 Display device 61 Control unit 62 Second wireless communication unit 63 Camera unit 70 Electronic pen 71 Light emission control unit 72 First wireless communication unit 73 Light emission unit 74 Switch unit

Claims (8)

An electronic blackboard system comprising: a display device for displaying an image on a display screen; and a plurality of electronic pens each emitting a light pulse to indicate a position on the display screen,
Each of the electronic pens
A light emitting unit for outputting the light pulse;
A switch unit for receiving a pressing operation;
A first wireless communication unit that performs wireless communication with the display device;
In response to the pressing operation, a first signal including identification information of the electronic pen is transmitted from the first wireless communication unit, and after the transmission of the first signal, the first signal is transmitted via the first wireless communication unit. A light emission control unit that receives a light emission command signal including identification information of the electronic pen and outputs the light pulse from the light emission unit, and
The display device
A second wireless communication unit that performs wireless communication with each of the electronic pens;
A camera unit provided so that the entire display screen is in an imaging range, and imaging the light pulse of each of the electronic pens;
The first signal is received from each of the electronic pens via the second wireless communication unit, the identification information of each electronic pen is obtained from the first signal, and the electronic pen is identified for each electronic pen. A light emitting command signal including information is transmitted from the second wireless communication unit, and
The control unit controls the transmission timing of the light emission command signal so that the plurality of electronic pens emit light at different timings, causes the camera unit to capture an image of each light pulse of the electronic pen, and An electronic blackboard system that acquires a position on the display screen indicated by each of the electronic pens based on an image. The electronic blackboard system according to claim 1,
Each of the electronic pens further includes a sensor unit that detects a movement direction and a movement amount of the electronic pen on the display screen, and the light emission control unit is configured to be set at predetermined intervals during a period when the switch unit is ON And a second signal including the movement direction and amount detected by the sensor unit and identification information of the electronic pen is transmitted from the first wireless communication unit,
The control unit receives the second signal from each of the electronic pens via the second wireless communication unit, and for each electronic pen, the movement direction and the amount of movement indicated by the second signal and the movement amount An electronic blackboard system that displays a drawing image indicating a trajectory of the electronic pen on the display screen on the display screen based on a position acquired from the captured image of the light pulse of the electronic pen. The electronic blackboard system according to claim 2,
The sensor unit is
A biaxial sensor for detecting a movement distance in the axial direction of each of the first and second axes orthogonal to each other;
An inclination sensor that detects an inclination of the first or second axis with respect to a predetermined direction in an in-plane direction of a plane including the first and second axes,
The electronic blackboard system, wherein the light emission control unit acquires the movement direction and the movement amount based on an output value of the biaxial sensor and an output value of the tilt sensor. The electronic blackboard system according to claim 1,
The control unit causes each of the electronic pens to repeatedly transmit the light emission command signal from the second wireless communication unit at different timings, and for each electronic pen, the electronic pen according to the light emission command signal. An electronic blackboard system in which a light pulse emitted from the electronic pen is imaged by the camera unit, and a drawing image indicating a locus of the electronic pen on the display screen is displayed on the display screen based on the captured image. The electronic blackboard system according to any one of claims 1 to 4,
The electronic blackboard system, wherein the display device includes a projection unit that projects an image on the display screen. An electronic pen used in combination with a display device that displays an image on a display screen,
A light emitting unit for outputting a light pulse;
A switch unit for receiving a pressing operation;
A wireless communication unit for performing wireless communication with the display device;
In response to the pressing operation, a first signal including identification information of the electronic pen is transmitted from the wireless communication unit, and light emission including the identification information is transmitted via the wireless communication unit after the transmission of the first signal. A light emission control unit that receives a command signal and outputs the light pulse from the light emission unit. A display device that displays an image on the display screen, each used in combination with a plurality of electronic pens that emit light pulses to indicate a position on the display screen,
A wireless communication unit that performs wireless communication with each of the electronic pens;
A camera unit provided so that the entire display screen is in an imaging range, and imaging the light pulse of each of the electronic pens;
A control unit that receives identification information of the electronic pen from each of the electronic pens via the wireless communication unit, and transmits a light emission command signal including the identification information of the electronic pen from the wireless communication unit for each electronic pen; Have
The control unit controls the transmission timing of the light emission command signal so that the plurality of electronic pens emit light at different timings, causes the camera unit to capture an image of each light pulse of the electronic pen, and A display device that acquires a position on the display screen indicated by each of the electronic pens based on an image. An electronic pen position detection method performed in an electronic blackboard system having a display device for displaying an image on a display screen, and a plurality of electronic pens each emitting a light pulse to indicate a position on the display screen. And
Each of the electronic pens wirelessly transmits a first signal including identification information of the electronic pen to the display device in response to a pressing operation.
The display device receives the first signal from each of the electronic pens, acquires identification information of each electronic pen, and the plurality of electronic pens emit light at different timings. Wirelessly transmitting a light emission command signal including the identification information of the electronic pen,
Each of the electronic pens emits the light pulse according to a light emission command signal including identification information of the own electronic pen among light emission command signals transmitted from the display device,
The display device causes the camera unit to capture the light pulse emitted by each of the electronic pens, and acquires a position on the display screen indicated by each of the electronic pens based on the captured image. Pen position detection method.

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