JP2016171476A - Decoder, decoding method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decoder, a decoding method and a program which enables decoding with excellent environmental tolerance in the information transmission using color modulation signal.SOLUTION: A decoding part 234 in a receiver 200 determines whether a hue value and a lightness value obtained from each imaging are deviated or not from a hue value reference value and a brightness reference value, in red (R), green (G) and blue (B), respectively. When the hue value and the lightness value obtained from each imaging are deviated from the hue reference value and the brightness reference value, the decoding part 234 corrects the hue reference value and the brightness reference value.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a decoding device, a decoding method, and a program.

  In information transmission using visible light (visible light communication), color images including time-series change patterns of the three primary colors of red (R), green (G), and blue (B) are acquired, and these color images are acquired. There is a technique for decoding into bit data from the regularity of the change pattern in (see, for example, Patent Document 1).

JP 2013-255253 A

  The above-described visible light communication technique is a technique useful in an image sensor, particularly a camera for image acquisition. On the other hand, the detection width of red (R), green (G), and blue (B) is easily influenced by the shooting environment, and particularly the color change caused by white balance adjustment and the influence of brightness by exposure control. It is easy to receive. If the influence on the detection width of red (R), green (G), and blue (B) is caused only by the color change, the problem can be solved by adjusting the white balance. Is also influenced by the brightness of the shooting environment, and until now, it was not considered until it was taken into account.

  The present invention has been made in view of such problems, and provides a decoding device, a decoding method, and a program that enable decoding with excellent environmental resistance in information transmission using a color modulation signal. Objective.

In order to achieve the above object, a decoding device according to the present invention provides:
Acquisition means for acquiring a color image;
Decoding means for decoding information from a predetermined distance interval on the color space;
The color space information included in the color image acquired by the acquisition unit is controlled to match the color space information used as a reference by the decoding unit, and information is decoded from a predetermined distance interval included in the color space information included in the color image. Decoding control means for controlling to
It is characterized by providing.

  ADVANTAGE OF THE INVENTION According to this invention, the decoding excellent in environmental tolerance is attained in the information transmission using a color modulation signal.

It is a figure which shows the structure of the optical communication system which concerns on embodiment of this invention. It is a figure which shows the structure of the transmitter shown in FIG. It is a figure which shows the structure of the receiver shown in FIG. It is a figure which shows an example of color space. It is a figure which shows an example of a color plane. It is a flowchart which shows the operation | movement of the reception process by a receiver.

  Hereinafter, an optical communication system according to an embodiment of the present invention will be described. An optical communication system 1 according to an embodiment of the present invention includes a transmission device 100 and a reception device 200 as shown in FIG.

  In the optical communication system 1, the transmission device 100 and the reception device 200 can communicate from the transmission device 100 to the reception device 200 using light as a communication medium.

  The transmitting apparatus 100 converts information to be communicated to the receiving apparatus 200 into an optical signal that changes in time series of red (R), green (G), and blue (B), which is visible light, by modulation. .

  The receiving device 200 is a smartphone, for example, and receives an optical signal from the transmitting device 100 by imaging the transmitting device 100 included in the imaging range. In addition, the receiving device 200 displays an image obtained by imaging. The receiving device 200 also decodes and displays information to be communicated from the received optical signal.

  Next, the transmission device 100 will be described. As illustrated in FIG. 2, the transmission device 100 includes a control unit 102, a memory 104, and a transmission unit 114.

  The control unit 102 includes a CPU (Central Processing Unit), and executes software processing according to a program stored in the memory 104, and functions to realize various functions included in the transmission device 100.

  The memory 104 is, for example, a RAM (Random Access Memory) serving as a work area and a ROM (Read Only Memory) storing a basic operation program. The memory 104 stores various information (programs and the like) used for control and the like in the transmission device 100.

  The encoding / modulating unit 110 in the control unit 102 encodes information to be communicated into a bit data string. Furthermore, the encoding / modulation unit 110 performs digital modulation based on the bit data string. For example, 4PPM (Pulse Position Modulation) using a carrier wave having a frequency of 28.8 (kHz) is employed as the modulation method. Based on the signal generated by the encoding / modulating unit 110, the driving unit 112 in the control unit 102 sends red (R), green (G), and blue (visible light) having different wavelengths to the transmission unit 114. The control of changing the light of B) temporally with the same luminance and with the change period t1 is performed.

  The transmission unit 114 is, for example, a light emitting diode (LED), and the light of each wavelength of red (R), green (G), and blue (B) with the same luminance is controlled by the drive unit 112. The output is output while changing in time at the change period t1.

  Next, the receiving apparatus 200 will be described. The receiving device 200 displays a captured image and functions as a communication device for receiving information from the transmitting device 100. As illustrated in FIG. 3, the reception device 200 includes a control unit 202, a memory 204, an operation unit 206, a display unit 207, a wireless communication unit 208, an antenna 210, and an imaging unit 214.

  The control unit 202 is configured by a CPU. The control unit 202 functions to realize various functions included in the reception device 200 by executing software processing according to a program stored in the memory 204.

  The memory 204 is, for example, a RAM or a ROM. The memory 204 stores various information (programs and the like) used for control and the like in the receiving device 200.

  The operation unit 206 is a touch panel disposed on the upper surface of the display area of the display unit 207, and is an interface used for inputting user operation details. The display unit 207 includes, for example, an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), an EL (Electro-Luminescence) display, and the like, and displays an image.

  The wireless communication unit 208 is configured using, for example, a radio frequency (RF) circuit, a base band (BB) circuit, or the like. The wireless communication unit 208 transmits and receives wireless signals via the antenna 210. The wireless communication unit 208 also modulates the transmission signal and demodulates the reception signal.

  The imaging unit 214 is disposed on the surface of the housing of the receiving device 200 opposite to the surface on which the display unit 207 is installed. The imaging unit 214 includes a lens and a light receiving element. The lens is composed of a zoom lens or the like, and moves by zoom control and focus control by the control unit 202. The imaging angle of view and optical image of the imaging unit 214 are controlled by movement of the lens. The light receiving element is composed of a plurality of light receiving elements regularly arranged two-dimensionally on the light receiving surface. The light receiving element is, for example, an imaging device such as a photodiode, a Bayer array color filter, or a three-plate CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor).

  The imaging unit 214 performs imaging in an imaging cycle t2 that is the same as the light change cycle t1 in the transmission unit 114 in the transmission device 100 and in a period (exposure period) t3 required for one imaging. The imaging unit 214 captures (receives light) the incident optical image with an imaging field angle within a predetermined range based on a control signal from the control unit 202, and sequentially controls the image signal within the imaging field angle. Output to.

  Each time the image signal from the imaging unit 214 is input, the image generation unit 232 in the control unit 202 converts the image signal into digital data to generate a frame.

  The decoding unit 234 in the control unit 202 searches for a change region that is a location where a hue change occurs due to a change in wavelength in a frame that is continuously input in time series. Specifically, the decoding unit 234 determines the brightness of each pixel in the image data of the frame. Further, the decoding unit 234 receives a light having a wavelength corresponding to the color of light emitted from the transmission unit 114 in the transmission device 100 for a pixel whose brightness is equal to or greater than a predetermined value, and a candidate for a change region where a hue change occurs. (Candidate area: blinking pattern).

  When there is a candidate area, the decoding unit 234 thereafter acquires the hue value (wavelength type) and brightness of the candidate area in the frame for each imaging. Here, the color is specified by hue (H: Hue), saturation (S: Saturation), and lightness (V: Value), and is specified by a position on the color space of the cylinder as shown in FIG. In the color space of FIG. 4, the circumferential direction indicates hue (H), the height direction (vertical direction) indicates lightness (V), and the radial direction indicates saturation (S). Further, a plane (color plane) when FIG. 4 is viewed from above is shown in FIG. Note that black has no hue, saturation, or brightness. The memory 204 stores reference values (hue reference values) of red (R), green (G), and blue (B) hue values, and lightness values of red (R), green (G), and blue (B). A reference value (brightness reference value) is stored. 4 and 5, the red (R) hue reference value and lightness reference value are at the position 503a, the green (G) hue reference value and the lightness reference value are at the position 501 and blue (B). The hue reference value and the lightness reference value are at position 502.

  The decoding unit 234 determines that the acquired hue value is within a predetermined range centered on the red (R) hue reference value, within a predetermined range centered on the green (G) hue reference value, and blue (B) hue reference. It is determined whether the value is within a predetermined range centered on the value. 4 and 5, a predetermined range centered on the red (R) hue reference value is a red determination region, and a predetermined range centered on the green (G) hue reference value is a green determination region. A predetermined range centered on the hue reference value of blue (B) is a blue determination region.

  The acquired hue value is within a predetermined range centering on the red (R) hue reference value (within the red determination area), within a predetermined range centering on the green (G) hue reference value (within the green determination area), If it is not within a predetermined range (within the blue determination area) centered on the hue reference value of blue (B), the decoding unit 234 cannot set the color plane, and the candidate area is not a change area. It is determined that it is noise.

  On the other hand, the acquired hue value is within a predetermined range (within the red determination region) centered on the red (R) hue reference value, and within a predetermined range (within the green determination region) centered on the green (G) hue reference value. ) And blue (B) within the predetermined range (within the blue determination area) centered on the hue reference value, the decoding unit 234 can set the color plane, and the candidate area is the change area. It is determined that In this case, the decoding unit 234 determines a color (any of red (R), green (G), and blue (B)) corresponding to the hue value of the change region (clustering). Here, if the obtained hue value is within a predetermined range (within the red determination region) centered on the red (R) hue reference value, the decoding unit 234 determines red (R) and green (G). Is determined to be green (G) if it is within a predetermined range centered on the hue reference value of (B) and within a predetermined range (within the blue determination region) centered on the hue reference value of Blue (B). If there is, it is determined as blue (B).

  Further, the decoding unit 234 determines whether or not the hue value and the brightness value acquired for each imaging are different from the hue reference value and the brightness reference value for each of red (R), green (G), and blue (B). Determine. Specifically, for each of red (R), green (G), and blue (B), the decoding unit 234 determines that the hue value acquired for each imaging is out of a predetermined range centered on the hue reference value (red determination). It is determined whether it is outside the region, outside the green determination region, outside the blue determination region, and whether the brightness value acquired for each imaging is outside a predetermined range centered on the brightness reference value.

  When the hue value acquired for each imaging is different from the hue reference value, the decoding unit 234 corrects the hue reference value so as to match. Specifically, the decoding unit 234 replaces the hue reference value with the average value of the hue values acquired for each imaging for the color in which the deviation between the hue value acquired for each imaging and the hue reference value occurs.

  In addition, when the brightness value acquired for each imaging is different from the brightness reference value, the decoding unit 234 corrects the brightness reference value. Specifically, the decoding unit 234 replaces the lightness reference value with the average value of the lightness values acquired for each image capturing for the color in which the difference between the lightness value acquired for each image capturing and the lightness reference value occurs.

  For example, in FIGS. 4 and 5, for red (R), the hue reference value and the brightness reference value are at the position of 503a, and the hue value and the brightness value acquired for each imaging are at the position of 503b. In this case, the decoding unit 234 sets the position of 503b as a new hue reference value and lightness reference value corresponding to red (R).

  The hue reference value and the brightness reference value corrected in this way are used for subsequent color determination.

  After correcting the hue reference value and the lightness reference value, the decoding unit 234 controls to decode the bit data string corresponding to each color of red (R), green (G), and blue (B), and sets the information to be communicated. get.

  The image generation unit 232 generates an image of communication target information acquired by the decoding unit 234. A display control unit 236 in the control unit 202 performs control to display an image of communication target information on the display unit 207.

  Next, the operation of the optical communication system 1 will be described. In the optical communication system 1, transmission processing by the transmission device 100 and reception processing by the reception device 200 are performed.

  An encoding / modulation unit 110 in the control unit 102 of the transmission apparatus 100 encodes information to be communicated into a bit data string, and further performs digital modulation based on the bit data string.

  Next, the drive unit 112 in the control unit 102 transmits red (R), green (G), and blue (B) light to the transmission unit 114 based on the signal generated by the encoding / modulation unit 110. Is controlled with time in the light emission cycle t1. As a result, the transmission unit 114 controls the drive unit 112 to control red (R), green (G), and blue (B) light with the same luminance and the light emission period based on the modulated communication target information. Output at t1.

  FIG. 6 is a flowchart illustrating an operation of reception processing by the reception device 200. When the user of the receiving apparatus 200 recognizes that the light hue of the transmitting unit 114 in the transmitting apparatus 100 has changed, an operation for performing imaging by starting an application program for acquiring communication target information I do. The imaging unit 214 in the receiving apparatus 200 performs imaging in accordance with a user operation, and sequentially outputs image signals within the imaging field angle to the control unit 202. Each time the image signal from the imaging unit 214 is input, the image generation unit 232 in the control unit 202 converts the image signal into digital data to generate a frame. The decoding unit 234 in the control unit 202 acquires, as candidate areas (flashing patterns), pixels whose brightness is a predetermined value or more among the pixels in the image data of the frame (step S101).

  If there is a candidate area, the decoding unit 234 acquires the hue value and the brightness value of the candidate area in the frame for each imaging, and determines whether or not the color plane can be set (step S102). . Specifically, the decoding unit 234 determines that the acquired hue value is within a predetermined range (within the red determination region) centered on the red (R) hue reference value and centered on the green (G) hue reference value. It is determined whether it is within the predetermined range (within the green determination region) or within the predetermined range (within the blue determination region) centered on the blue (B) hue reference value (step S102).

  When the color plane cannot be set (step S102; NO), the decoding unit 234 determines that the candidate area is not a change area but noise (step S110), and ends the reception process.

  On the other hand, when the color plane can be set (step S102; YES), the decoding unit 234 determines that the candidate area is a change area, and determines colors (red (R), green (red) corresponding to the hue value of the change area. G) or blue (B)) is determined (clustering) (step S103).

  Further, the decoding unit 234 determines whether or not the hue value and the brightness value acquired for each imaging are different from the hue reference value and the brightness reference value for each of red (R), green (G), and blue (B). Is determined (step S104).

  When the hue value acquired for each imaging is different from the hue reference value and the brightness reference value (step S104; YES), the decoding unit 234 corrects the hue reference value and the brightness reference value (step S105).

  After correcting the hue reference value and lightness reference value in step S105, or when it is determined that the hue value and lightness value acquired for each imaging in step S104 are not different from the hue reference value and lightness reference value (step (S104; NO), the decoding unit 234 decodes the bit data string corresponding to each color of red (R), green (G), and blue (B), and acquires communication target information (step S106).

  As described above, in the optical communication system 1 according to the present embodiment, the decoding unit 234 in the receiving device 200 acquires each of red (R), green (G), and blue (B) for each imaging. It is determined whether the hue value and the lightness value are different from the hue reference value and the lightness reference value. If they are different, the hue reference value and the lightness reference value are corrected. As a result, even if the hue and lightness reference values of red (R), green (G), and blue (B) are different from the hue and lightness obtained by imaging, the deviation is eliminated. Color determination can be performed appropriately, and decoding with excellent environmental resistance becomes possible.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation and application are possible. For example, in the above-described embodiment, the case of using red (R), green (G), and blue (B) light, which is visible light, for communication is described, but other colors of visible light may be used, Furthermore, light other than visible light such as infrared rays may be used.

  Moreover, the transmission part 114 in the transmission apparatus 100 may be comprised in a part of display part, for example.

  The receiving device 200 may be any device as long as it can capture an image. For example, a PHS (Personal Handy-phone System), a PDA (Personal Digital Assistant or Personal Data Assistance), a tablet PC (Personal Computer), a game device, a portable music player, and the like may be used.

  Alternatively, a device having both the function of the receiving device 200 and the function of the transmitting device 100 may be prepared so that both functions can be used properly according to the situation.

  In each of the above embodiments, the program to be executed is a computer-readable recording such as a flexible disk, a CD-ROM (Compact Disc Read-Only Memory), a DVD (Digital Versatile Disc), and an MO (Magneto-Optical disc). A system that executes the above-described processing may be configured by storing and distributing the program on a medium and installing the program.

  Alternatively, the program may be stored in a disk device or the like of a predetermined server on a network NW such as the Internet, and may be downloaded, for example, superimposed on a carrier wave.

  Note that when the above functions are realized by sharing an OS (Operating System) or when the functions are realized by cooperation between the OS and an application, only the part other than the OS may be stored in a medium and distributed. You may also download it.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to the specific embodiment which concerns, This invention includes the invention described in the claim, and its equivalent range It is. Hereinafter, the invention described in the scope of claims of the present application will be appended.

(Appendix 1)
Acquisition means for acquiring a color image;
Decoding means for decoding information from a predetermined distance interval on the color space;
The color space information included in the color image acquired by the acquisition unit is controlled to match the color space information used as a reference by the decoding unit, and information is decoded from a predetermined distance interval included in the color space information included in the color image. Decoding control means for controlling to
A decoding apparatus comprising:

(Appendix 2)
Control means for controlling the acquisition means to continuously acquire a color image;
Determination means for determining a tendency of color space information of the color image from a plurality of color images acquired by control by the control means;
With
The decoding apparatus according to appendix 1, wherein the comparison controlled by the decoding control means includes a determination result by the determining means.

(Appendix 3)
The decoding control unit compares the color space information which is stored in advance as a reference by the decoding unit and the color space information which the color image has, and based on the comparison result, the color space which the color image has The decoding apparatus according to appendix 1 or 2, further comprising correction means for correcting the information so as to match the color space information used as a reference by the decoding means.

(Appendix 4)
The color space is a space in which at least hue and lightness are set as parameters,
The decoding apparatus according to appendix 3, wherein the correction unit corrects the two parameters so as to follow a specific tendency.

(Appendix 5)
The decoding device according to any one of appendices 1 to 4, wherein the acquisition unit includes an imaging unit.

(Appendix 6)
An acquisition step of acquiring a color image;
A decoding step of decoding information from a predetermined distance interval on the color space;
Color space information included in the color image acquired in the acquisition step is controlled to match the color space information used as a reference in the decoding step, and information is obtained from a predetermined distance interval included in the color space information included in the color image. A decoding control step for controlling the decoding to
The decoding method characterized by including.

(Appendix 7)
Computer
Acquisition means for acquiring a color image;
Decoding means for decoding information from a predetermined distance interval on the color space;
The color space information included in the color image acquired by the acquisition unit is controlled to match the color space information used as a reference by the decoding unit, and information is decoded from a predetermined distance interval included in the color space information included in the color image. Decoding control means for controlling to
Program to function as.

  DESCRIPTION OF SYMBOLS 1 ... Optical communication system, 100 ... Transmission apparatus, 102 ... Control part, 104 ... Memory, 110 ... Coding / modulation part, 112 ... Drive part, 114 ... Transmission part, 200 ... Reception apparatus, 202 ... Control part, 204 ... Memory 206, operation unit 207, display unit, 208, wireless communication unit, 210, antenna, 214, imaging unit, 232, image generation unit, 234, decoding unit, 236, display control unit

Claims (7)

Acquisition means for acquiring a color image;
Decoding means for decoding information from a predetermined distance interval on the color space;
The color space information included in the color image acquired by the acquisition unit is controlled to match the color space information used as a reference by the decoding unit, and information is decoded from a predetermined distance interval included in the color space information included in the color image. Decoding control means for controlling to
A decoding apparatus comprising: Control means for controlling the acquisition means to continuously acquire a color image;
Determination means for determining a tendency of color space information of the color image from a plurality of color images acquired by control by the control means;
With
The decoding apparatus according to claim 1, wherein the comparison controlled by the decoding control unit includes a determination result by the determination unit.   The decoding control unit compares the color space information which is stored in advance as a reference by the decoding unit and the color space information which the color image has, and based on the comparison result, the color space which the color image has 3. The decoding apparatus according to claim 1, further comprising a correction unit that corrects information so that the information matches color space information used as a reference by the decoding unit. The color space is a space in which at least hue and lightness are set as parameters,
4. The decoding apparatus according to claim 3, wherein the correction unit corrects the two parameters so as to follow a specific tendency.   The decoding apparatus according to claim 1, wherein the acquisition unit includes an imaging unit. An acquisition step of acquiring a color image;
A decoding step of decoding information from a predetermined distance interval on the color space;
Color space information included in the color image acquired in the acquisition step is controlled to match the color space information used as a reference in the decoding step, and information is obtained from a predetermined distance interval included in the color space information included in the color image. A decoding control step for controlling the decoding to
The decoding method characterized by including. Computer
Acquisition means for acquiring a color image;
Decoding means for decoding information from a predetermined distance interval on the color space;
The color space information included in the color image acquired by the acquisition unit is controlled to match the color space information used as a reference by the decoding unit, and information is decoded from a predetermined distance interval included in the color space information included in the color image. Decoding control means for controlling to
Program to function as.

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