JP4214288B2 - Information transmission system and information transmission method - Google Patents

Description

  The present invention relates to an information transmission system and an information transmission method using light.

  It has been a long time since the concept of ubiquitous computing was proposed. In ubiquitous computing, communication with devices ubiquitous in space is required. As a technology for that purpose, many studies are currently being made in the direction of expanding conventional data communication technologies such as wireless communication using radio waves and infrared rays and wired communication. Conventional wireless communication can control only three parameters, ie, “direction”, “directivity”, and “intensity” of electromagnetic waves spreading over all solid angles. For this reason, when communicating with many objects, it is necessary to perform time division multiplexing or frequency division multiplexing. Therefore, the number of objects and the amount of data that can be communicated are often in a trade-off relationship.

  The present invention provides a system and method capable of transmitting information corresponding to a position in a real space with a higher “spatial resolution” than conventional wireless communication by performing space division multiplexing. It is aimed.

  An information transmission system according to the present invention includes a transmission device and a reception device. The transmission device includes a transmission unit that projects an image composed of m (m: any natural number) pixels onto the reception device. Of the m pixels, the light in the n-th pixel (any of n: 1 to m-th or all) is time-modulated. The receiving device includes a light receiving unit that receives the time-modulated light, and a control unit that demodulates the received light and extracts information.

  The transmission unit is, for example, a projector.

  For example, the transmission device can generate the image by superimposing a presentation image and a time-modulated communication signal.

  The light receiving unit is, for example, a photodiode.

The information transmission method of the present invention comprises the following steps:
(1) It is composed of m pixels (m is an arbitrary natural number), and among the m pixels, light in the nth pixel (n: any one or all of n to 1 to m) is time-modulated. Sending the image being processed;
(2) receiving the time-modulated light and then demodulating it to extract information;

  Another information transmission system according to the present invention includes a transmission device and a reception device. The transmission device includes a transmission unit that projects an image composed of m (m: any natural number) pixels onto the reception device. Of the m pixels, the light in the n-th pixel (any of n: 1 to m-th or all) is time-modulated. The receiving device includes a light receiving unit that receives the time-modulated light, a control unit that demodulates the received light and extracts information, and a reflection unit that retroreflects the light transmitted from the transmission unit. Prepare. The reflection unit includes a shutter that changes the intensity of light reflected by the reflection unit.

  The transmission device may further include a camera that receives the reflected light from the reflecting unit, and a processing unit that demodulates the reflected light received by the camera and extracts information.

  The control unit of the receiving device may control the operation of the shutter.

  The receiving apparatus may further include a detection unit for inputting information to the control unit.

  The transmission device may include a measurement unit that measures a user's viewpoint position, and may project an image corresponding to the viewpoint position.

Another information transmission method according to the present invention comprises the following steps:
(1) It is composed of m pixels (m is an arbitrary natural number), and among the m pixels, light in the nth pixel (n: any one or all of n to 1 to m) is time-modulated. Projecting the image being rendered;
(2) receiving the time-modulated light, and then demodulating and extracting information;
(3) retroreflecting the light projected from the transmitter;
(4) modulating the reflected light by the retroreflection;
(5) receiving the reflected light, and then demodulating and extracting information;

  In the information transmission system of the present invention, light in p pixels (where 1 ≦ p ≦ m) of the m pixels may be time-modulated with a position information signal.

  The control unit in the information transmission system of the present invention obtains the position information signal by demodulating the light, and based on the position information signal and known spatial coordinates of the transmission device or the reception device, The configuration may be such that the positional relationship between the transmitting device and the receiving device is calculated.

  The control unit in the information transmission system of the present invention demodulates the light to obtain the position information signal, and based on temporal variation of the position information signal due to relative movement between the transmission device and the reception device. The configuration may be such that the positional relationship between the transmitting device and the receiving device is calculated.

  According to the information transmission system and method of the present invention, different information can be simultaneously transmitted to a large number of objects dispersed in a space.

(Configuration of the first embodiment)
Hereinafter, a first embodiment of an information transmission system according to the present invention will be described with reference to FIGS. In these figures, symbol A indicates projection light, and symbol B indicates reflected light.

  This system includes a transmission device 1, a plurality of reception devices 2, and a screen 3 (see FIG. 1).

  The transmission device 1 includes a transmission unit 11, a communication signal generation unit 12, a control unit 13, a processing unit 14, a camera 15, and a half mirror 16.

  In this embodiment, a projector is used as the transmission unit 11. Any projector such as a DLP projector or a liquid crystal projector can be used as the projector. However, in order to increase the time modulation frequency of light, a DLP projector is suitable. In short, the transmission unit 11 may be anything that can project the light divided for each pixel onto the object. The transmission unit 11 is configured to transmit an image made up of m (m: any natural number) pixels to the reception device 2.

  The communication signal generation unit 12 is configured to generate an image signal to be projected and send it to the transmission unit 11. The communication signal generation unit 12 is configured to send an image signal composed of m pixels to the transmission unit 11. Further, the communication signal generation unit 12 temporally modulates light in the nth (n: any one or all of the 1st to mth) pixels among the m pixels. The modulation method may be any of intensity modulation, frequency modulation, and phase modulation, and various modulation methods such as analog modulation, digital modulation, and pulse modulation can be used.

  Detailed operations of the control unit 13 and the processing unit 14 will be described later in the description of the transmission method. Note that the communication signal generation unit 12, the control unit 13, and the processing unit 14 described above can be configured by hardware or computer software.

  The camera 15 receives a part of the light retroreflected by each receiving device 2. The camera 15 sends the acquired image to the processing unit 14 as an image signal. The camera 15 can be constituted by a CCD camera, for example.

  The half mirror 16 is configured to send a part of the light reflected by the receiving device 2 to the camera 15. Accordingly, the camera 15 is arranged at a position optically conjugate with the transmission unit 11.

  The plurality of receiving devices 2 are arranged in a two-dimensional direction (that is, spatially) apart from each other on the front surface of the screen 3 (see FIG. 1). The position of the receiving apparatus 2 may be any position that can receive the projection light from the transmitting apparatus 1. Each receiving device 2 includes a light receiving unit 21, a reflecting unit 22, a control unit 23, and a detecting unit 24 (see FIG. 2). Although the operating power supply of the receiving device 2 is not shown, any power source such as a battery, a power supply line, or a wireless power supply can be used.

  The light receiving unit 21 receives a part of the projection light A from the transmission unit 11 of the transmission device 1. The light receiving unit 21 receives time-modulated light depending on the position where it is arranged. For example, a photodiode can be used as the light receiving unit 21.

  The reflection unit 22 includes a retroreflecting material 221 and a shutter 222 (see FIG. 3). The retroreflective material is a material that reflects light toward a light source of incident light. Various types of retroreflecting materials are known, such as those using beads, those using prisms, and those using corner cube mirrors (generally composed of three mirrors). With this configuration, the reflection unit 22 retroreflects the light transmitted from the transmission unit 11.

  The shutter 222 is disposed in front of the retroreflecting material 221 (on the light source side). The shutter 222 is configured to change the intensity of reflected light from the reflection unit 22 to the transmission device 1 by opening and closing the shutter 222. Changing the intensity includes completely blocking the reflected light and reducing the reflected light intensity. As the shutter 222, for example, a liquid crystal shutter or a mechanical shutter can be used. When a corner cube mirror is used as the retroreflecting material, the reflected light intensity can also be modulated by vibrating any one of the mirrors. In this case, the vibrating mirror corresponds to the shutter of the present invention. In short, the shutter of the present invention may be any means that changes the intensity of reflected light, and may not be an independent mechanism as the shutter itself.

  The control unit 23 is configured to demodulate the light signal received by the light receiving unit 21 and extract information. As a demodulation method of the modulated light, various known methods can be used. For example, pulse phase modulation can be easily demodulated by a method using a PLL or the like. Further, the control unit 23 is configured to control the opening / closing operation of the shutter 222.

  The detection unit 24 can detect changes in temperature, light, etc. outside the apparatus. The detection unit 24 sends the detection result to the control unit 23.

  A retroreflecting material (not shown) is disposed on the surface of the screen 3.

(Operation of the first embodiment)
Next, an information transmission method using the system of the first embodiment will be described with reference to FIG.

(Step 4-1)
First, a communication signal is generated in the communication signal generation unit 12 according to a command from the control unit 13. This communication signal has m (m: any natural number) pixels. Further, among m pixels, the light in the nth pixel (n: any one or all of the 1st to mth pixels) is time-modulated. An image signal composed of such pixels is sent to the transmitter 11.

(Step 4-2)
The transmission unit 11 projects an image based on the image signal received from the control unit 13 toward the screen 3. This projected image is a bundle of projection light A for each pixel.

(Step 4-3)
The light receiving unit 21 of the receiving device 2 receives the projection light A at a position corresponding to each pixel. The light receiving unit 21 corresponding to the pixel to which the time-modulated light is transmitted receives the time-modulated light.

  The receiving devices 2 are arranged in a two-dimensional direction. Therefore, according to this embodiment, it is possible to simultaneously transmit time-modulated light to a large number of spatially dispersed receiving apparatuses 2.

(Step 4-4)
The control unit 23 analyzes the time-modulated light received by the light receiving unit 21 and extracts information contained therein. Information as the analysis result is output to an output device (not shown), for example. However, it is not essential to output the analysis result. For example, the analysis result may be used only for the internal operation of the receiving device 2.

(Step 4-5)
On the other hand, the detection unit 24 of the reception device 2 sends the detection result by the detection unit 24 to the control unit 23.

(Step 4-6)
The control unit 23 operates the shutter of the reflection unit 22 in response to information obtained from the time-modulated light or an input from the detection unit 24.

(Step 4-7)
In the reflection unit 22, if the shutter 222 is open, the reflected light from the retroreflecting material 221 passes through the shutter 222 and is sent toward the transmission unit 11. In the present embodiment, since the retroreflecting material is used, the received light can be reflected toward the transmitting unit 11 regardless of the position of the receiving device 2.

(Step 4-8)
Part of the reflected light transmitted to the transmission unit 11 is reflected by the half mirror 16 and received by the camera 15.

  Since the camera 15 of the present embodiment is disposed at a position optically conjugate with the transmission unit 11 via the half mirror 16, a specific pixel i in the transmission unit 11 is reflected by the reception device 2. The light enters the pixel i ′ of the camera at a position conjugate with the pixel i. For this reason, it is possible to easily determine that the light received by the pixel i ′ is from the receiving device 2 irradiated with the pixel i.

  Further, since the camera 15 and the transmission unit 11 are in an optically conjugate position, the light emitted from the transmission unit 11 and reflected by the retroreflecting material 221 is collected on the camera 15. Therefore, the luminance level of the light received by the camera 15 can be kept high.

(Step 4-9)
When the shutter 222 is closed, the reflected light from the retroreflecting material 221 is not sent to the transmission unit 11. That is, while the shutter 222 is closed, the intensity of the input light to the camera 15 is weak in the pixel corresponding to the reflection unit 22. Therefore, in this embodiment, the reflected light by retroreflection can be modulated (in this case, intensity modulation) by opening and closing the shutter 222.

(Step 4-10)
The processing unit 14 demodulates the time-modulated reflected light in the image signal acquired by the camera 15 and extracts information. The process of extracting information is performed as follows, for example. Since the image signal transmitted from the transmission unit 11 is confirmed, the communication signal generation unit 12 sends the image signal to the processing unit 14 and subtracts it from the image signal acquired by the camera 15. Then, the modulated reflected light component (that is, information carried on the reflected light) can be extracted.

  Therefore, according to this embodiment, communication between the transmission device 1 and the reception device 2 is possible.

(Step 4-11)
The control unit 13 receives the processing result of the processing unit 14 and sends a command for generating a new communication signal to the communication signal generating unit 12 in accordance with the information included in the reflected light. Subsequent operations are the same as described above.

(Configuration and operation of the second embodiment)
Next, an information transmission system according to a second embodiment of the present invention will be described with reference to FIGS. In the description of this embodiment, the same reference numerals are used for the same configurations as in the first embodiment described above, thereby simplifying the description.

  In this embodiment, both information transmission and image presentation can be performed. In the system of this embodiment, a measurement unit 17, a presentation image generation unit 18, and a half mirror 19 are added to the system of the first embodiment.

  The measuring unit 17 can measure the viewpoint position of the user 4 (see FIG. 5) using, for example, a position sensor or an acceleration sensor. The measurement unit 17 may be configured to measure the direction of the line of sight with light. In short, the measurement unit 17 may be anything that can measure the viewpoint position.

  The presentation image generation unit 18 generates an image that can be visually recognized by the user, separately from the communication signal. The presentation image generation unit 18 generates an image corresponding to the viewpoint position of the user 4 and sends it to the transmission unit 11 according to a command from the control unit 13.

  The half mirror 19 sends a part of the reflected light from the receiving device 2 to the user. In the second embodiment, the transmission unit 11 is disposed at a position optically conjugate with the viewpoint of the user.

Next, an information transmission method using the system of the second embodiment will be described with reference to FIG.
In the description of this transmission method, the method according to the first embodiment shown in FIG. 4 is assumed, and only different portions will be described. Accordingly, the same steps as those shown in FIG. 4 are denoted by the same reference numerals.

(Step 6-1 in FIG. 6)
In the method of the second embodiment, a presentation image is generated by the presentation image generation unit 18. The presentation image is sent to the transmission unit 11 by superimposing a communication signal, which is a time-modulated optical signal. The communication signal in the present embodiment is preferably a signal obtained by time-modulating the following signal, for example, so that the communication signal cannot be visually recognized.
(A) a short pulse signal that is invisible,
(B) a signal with a contrast that is not visible;
(C) A signal in a wavelength band that cannot be visually recognized, for example, infrared rays

  The image sent from the transmission unit 11 passes through the half mirror 19 and the half mirror 16 and is projected onto the screen 3 and the receiving device 2.

  The light retroreflected by the screen 3 is provided to the viewpoint of the user 4 through the half mirrors 16 and 19. Thereby, the user 4 can see the presentation image sent from the transmission unit 11. If the shutter 222 of the reflection unit 22 is in the open state, the projection light reflected by the retroreflecting material 221 can also be sent to the user 4. It is also possible to prevent the user from being aware of blinking in the pixel by sufficiently increasing the operation speed of the shutter 222 or reducing the modulation width (intensity difference) of the contrast in the pixel to be modulated. .

(Step 6-2)
In the method of the second embodiment, viewpoint position information is acquired by the measurement unit 17. This information is sent to the control unit 13. If the viewpoint position has changed, the control unit 13 sends new viewpoint position information to the presentation image generation unit 18 and instructs generation of the presentation image.

(Step 6-3)
The presentation image generation unit generates a presentation image corresponding to the viewpoint position based on the received viewpoint position information. The generated image is sent to the transmission unit 11 as in the case of Step 6-1. Subsequent operations are the same as described above.

  The information transmission system and method of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  For example, each component described above may exist as a functional block, and may not exist as independent hardware. As a mounting method, hardware or computer software may be used. Furthermore, one functional element in the present invention may be realized by a set of a plurality of functional elements, and a plurality of functional elements in the present invention may be realized by one functional element.

  Moreover, the functional element may be arrange | positioned in the position physically separated. In this case, the functional elements may be connected by a network.

  Furthermore, although the above-described information transmission system is premised on communication between the transmission device 1 and the reception device 2, it is not necessary to provide the reflection unit 22 in the reception device 2 when only transmission is sufficient.

  Furthermore, it is also possible to perform a position measuring device with the system of the present invention. An example of use in this case is as follows.

  First, independent IDs are assigned as position information signals to p pixels (where 1 ≦ p ≦ m) of m pixels transmitted from the transmission apparatus 1. Based on this ID, the light in the p pixels is time-modulated and transmitted from the transmitter 11. Here, the ID may be information indicating the position of the pixel.

  On the other hand, the control unit 23 of the receiving device 2 can receive an ID as a position information signal in the pixel by demodulating the time-modulated light.

  Here, if the spatial coordinates of the transmission device 1 or the reception device 2 are known, the positional relationship (for example, direction) between the transmission device 1 and the reception device 2 is determined based on the spatial coordinates and the acquired position information signal. Can be calculated.

  In addition, when the positional information signal varies with time due to relative movement between the transmission device 1 and the reception device 2 (for example, movement of the reception device 2), the transmission device and the reception device are based on this variation history. It is also possible to calculate the positional relationship.

1 is a block diagram showing a schematic configuration of an information transmission system according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of a receiving device used in the information transmission system of FIG. 1. FIG. 3 is a block diagram illustrating a schematic configuration of a reflection unit used in the receiving apparatus of FIG. 2. It is a flowchart for demonstrating the information transmission method using the information transmission system of FIG. It is a block diagram which shows the schematic structure of the information transmission system which concerns on 2nd Embodiment of this invention. It is a flowchart for demonstrating the information transmission method using the information transmission system of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission apparatus 11 Transmission part 12 Communication signal generation part 13 Control part 14 Processing part 15 Camera 16 Half mirror 17 Measurement part 18 Presented image generation part 19 Half mirror 2 Receiver 21 Light reception part 22 Reflection part 221 Retroreflective material 222 Shutter 23 Control unit 24 Detection unit 3 Screen 4 User A Projected light B Reflected light

Claims (14)

A transmission device and a reception device;
The transmission device includes a transmission unit that projects an image including m pixels (m: an arbitrary natural number) onto the reception device, and the nth (n: 1 to mth) of the m pixels. The light at said pixels is time-modulated,
The information receiving system, wherein the receiving device includes a light receiving unit that receives the time-modulated light, and a control unit that demodulates the received light and extracts information.   The information transmission system according to claim 1, wherein the transmission unit is a projector.   The information transmission system according to claim 1 or 2, wherein the transmission device generates the image by superimposing a presentation image and a time-modulated communication signal.   The information transmission system according to claim 1, wherein the light receiving unit is a photodiode. An information transmission method comprising the following steps:
(1) It is composed of m pixels (m is an arbitrary natural number), and among the m pixels, light in the nth pixel (n: any one or all of n to 1 to m) is time-modulated. Sending the image being processed;
(2) receiving the time-modulated light and then demodulating it to extract information; A transmission device and a reception device;
The transmission device includes a transmission unit that projects an image including m pixels (m: an arbitrary natural number) onto the reception device, and the nth (n: 1 to mth) of the m pixels. The light at said pixels is time-modulated,
The receiving device includes: a light receiving unit that receives the time-modulated light; a control unit that demodulates the received light to extract information; and a reflection unit that retroreflects the light transmitted from the transmission unit. With
The information transmission system, wherein the reflection unit includes a shutter that changes the intensity of light reflected by the reflection unit.   The transmission device further includes a camera that receives the reflected light from the reflection unit, and a processing unit that demodulates the reflected light received by the camera and extracts information. Information transmission system described in 1.   The information transmission system according to claim 6 or 7, wherein the control unit of the receiving device controls the operation of the shutter.   9. The information transmission system according to claim 8, wherein the reception device further includes a detection unit for inputting information to the control unit.   The transmission device includes a measuring unit that measures a user's viewpoint position, and is configured to project an image corresponding to the viewpoint position. The information transmission system according to item 1. Information transmission method comprising the following steps:
(1) It is composed of m pixels (m is an arbitrary natural number), and among the m pixels, light in the nth pixel (n: any one or all of n to 1 to m) is time-modulated. Projecting the image being rendered;
(2) receiving the time-modulated light, and then demodulating and extracting information;
(3) retroreflecting the light projected from the transmitter;
(4) modulating the reflected light by the retroreflection;
(5) receiving the reflected light, and then demodulating and extracting information;   11. The light in p pixels (where 1 ≦ p ≦ m) of the m pixels is time-modulated by a position information signal. Information transmission system described in 1.   The control unit demodulates the light to obtain the position information signal, and based on the position information signal and known spatial coordinates of the transmission apparatus or the reception apparatus, the transmission apparatus and the reception apparatus The information transmission system according to claim 12, wherein the positional relationship is calculated. The control unit demodulates the light to acquire the position information signal, and based on temporal variation of the position information signal due to relative movement between the transmission apparatus and the reception apparatus, the transmission apparatus and the reception 13. The information transmission system according to claim 12, wherein the information transmission system is configured to calculate a positional relationship with the apparatus.

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