JP2020096365A - Decoder, decoding method and program - Google Patents

Abstract

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), a color image including a time-series change pattern of the three primary colors of red (R), green (G), and blue (B) is acquired, and these color images are acquired. There is a technique for decoding into bit data from the regularity of the change pattern in (1) (for example, refer to Patent Document 1).

JP, 2013-255253, A

The visible light communication technique described above is a technique useful in an image sensor, particularly in a camera for image acquisition. On the other hand, the range of detection of red (R), green (G), and blue (B) is easily affected by the shooting environment, and particularly the color change caused by white balance adjustment and the influence of brightness due to 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, adjusting the white balance solves the problem, but actually the color change Is also affected by the brightness of the shooting environment, and until now, it has not been considered.

The present invention has been made in view of such a problem, and provides a decoding device, a decoding method, and a program capable of decoding with excellent environmental resistance in information transmission using a color modulation signal. To aim.

In order to achieve the above object, the decoding device according to the present invention,
An acquisition unit that acquires a time series change pattern of the three primary colors in a color image,
Decoding means for decoding into information based on each hue value in the color space of the three primary colors of the change pattern acquired by the acquisition means,
Control to replace each hue value in the color space of the three primary colors of the change pattern acquired by the acquisition unit with each hue value that the decoding unit uses as a reference, to form a time-series change pattern of the replaced hue value. Decoding control means for controlling decoding based on the information,
It is characterized by including.

According to the present invention, it is possible to perform decoding having excellent environmental resistance in 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 a color space. It is a figure which shows an example of a color plane. It is a flowchart which shows operation|movement of the receiving process by a receiver.

The optical communication system according to the embodiment of the present invention will be described below. The optical communication system 1 according to the embodiment of the present invention is configured to include 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 perform communication from the transmission device 100 to the reception device 200 using light as a communication medium.

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

The receiving device 200 is, for example, a smartphone, and receives the 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 the image obtained by imaging. Further, the receiving device 200 decodes the information of the communication target from the received optical signal and displays it.

Next, the transmitting device 100 will be described. As shown 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), 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/modulation unit 110 in the control unit 102 encodes information to be communicated into a bit data string. Further, the encoding/modulation unit 110 performs digital modulation based on the bit data string. As a modulation method, for example, 4PPM (Pulse Position Modulation) using a carrier having a frequency of 28.8 (kHz) is adopted. Based on the signal generated by the encoding/modulation unit 110, the drive unit 112 in the control unit 102 instructs the transmission unit 114 to transmit visible light having different wavelengths of red (R), green (G), and blue ( The control of changing the light of B) at the same brightness with time at the change cycle t1 is performed.

The transmitting unit 114 is, for example, a light emitting diode (LED), and under the control of the driving unit 112, lights of respective wavelengths of red (R), green (G), and blue (B) with the same luminance, The output is made while changing with time at the change period t1.

Next, the receiving device 200 will be described. The receiving device 200 displays a captured image and also functions as a communication device for receiving information with the transmitting device 100. As shown in FIG. 3, the receiving 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 composed of a CPU. The control unit 202 functions to realize various functions included in the receiving 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 arranged on the upper surface of the display area of the display unit 207, and is an interface used to input the operation content of the user. The display unit 207 includes, for example, an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), an EL (Electro-Luminescence) display, and displays an image.

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

The imaging unit 214 is arranged 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 is composed of a lens and a light receiving element. The lens is composed of a zoom lens or the like, and is moved by zoom control and focusing control by the control unit 202. The imaging angle of view and the optical image of the imaging unit 214 are controlled by moving the lens. The light receiving element is composed of a plurality of light receiving elements which are regularly two-dimensionally arranged on the light receiving surface. The light receiving element is, for example, a photodiode, a Bayer array color filter mounted, or an imaging device such as a three-plate CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor).

The image capturing unit 214 performs image capturing at the same image capturing period t2 as the light changing period t1 in the transmitting unit 114 in the transmitting device 100 and during a period (exposure period) t3 required for one image capturing. The imaging unit 214 images (receives) the received optical image at an imaging field angle within a predetermined range based on a control signal from the control unit 202, and sequentially controls the image signals within the imaging field angle. Output to.

The image generation unit 232 in the control unit 202 generates a frame by converting the image signal into digital data each time the image signal from the imaging unit 214 is input.

The decoding unit 234 in the control unit 202 searches for a change region that is a portion where a hue change due to a wavelength change occurs in frames that are 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 the wavelength light corresponding to the emission color from the transmission unit 114 in the transmission device 100 to the pixel having the brightness equal to or higher than the predetermined value, and thus the candidate for the change region, which is the portion where the hue change occurs. (Candidate region: blinking pattern).

When the candidate area exists, the decoding unit 234 thereafter acquires the hue value (wavelength type) and the lightness of the candidate area in the frame for each imaging. Here, the color is specified by the hue (H:Hue), the saturation (S:Saturation), and the brightness (V:Value), and is specified by the position on the color space of the cylinder as shown in FIG. In the color space of FIG. 4, the circumferential direction represents hue (H), the height direction (vertical direction) represents lightness (V), and the radial direction represents saturation (S). A plane (color plane) viewed from above in FIG. 4 is shown in FIG. It should be noted that black has neither hue, saturation nor lightness. The memory 204 stores reference values (hue reference values) of hue values of red (R), green (G), and blue (B) and brightness values of red (R), green (G), and blue (B). A reference value (brightness reference value) is stored. 4 and 5, the hue reference value and the lightness reference value of red (R) are at the position of 503a, the hue reference value and the lightness reference value of green (G) are at the position of 501, and the 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 hue reference value of red (R), within a predetermined range centered on the hue reference value of green (G), and the hue reference value of blue (B). It is determined whether the value is within a predetermined range centered on the value. In FIGS. 4 and 5, the red determination area is within a predetermined range centered on the hue reference value of red (R), and the green determination area is within a predetermined range centered on the hue reference value of green (G). , A predetermined range centered on the hue reference value of blue (B) is a blue determination area.

The obtained hue value is within a predetermined range centered on the red (R) hue reference value (red determination area), within a predetermined range centered on the green (G) hue reference value (green determination area), If it is neither within the predetermined range (in 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 the change area. , It is determined to be noise.

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

Further, the decoding unit 234 determines whether or not the hue value and the lightness value acquired for each image pickup are different from the hue reference value and the lightness reference value for each of red (R), green (G), and blue (B). To judge. Specifically, the decoding unit 234 determines that the hue value acquired for each image pickup for each of red (R), green (G), and blue (B) is outside a predetermined range around the hue reference value (red determination). Outside the area, outside the green judgment area, outside the blue judgment area) and whether or not 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 image pickup is deviated from the hue reference value, the decoding unit 234 corrects the hue reference value to match. Specifically, the decoding unit 234 replaces the hue reference value with the average value of the hue values obtained for each image pickup, for the color in which the hue value obtained for each image pickup and the hue reference value are displaced.

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 pickup for the color in which the lightness value acquired for each image pickup and the lightness reference value are displaced.

For example, in FIGS. 4 and 5, for red (R), the hue reference value and the lightness reference value are at the position 503a, and the hue value and the lightness value acquired for each image pickup are at the position 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 lightness reference value corrected in this way are used for the subsequent color determination.

After the correction of 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 communication target information. get.

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

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

The encoding/modulation unit 110 in the control unit 102 of the transmission device 100 encodes the 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 sends 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 the light emission period t1. As a result, the transmission unit 114, under the control of the drive unit 112, emits red (R), green (G), and blue (B) light at the same brightness and at the light emission cycle based on the modulated information of the communication target. Output at t1.

FIG. 6 is a flowchart showing the operation of the receiving process by the receiving device 200. When the user of the receiving device 200 recognizes the state in which the hue of the light of the transmitting unit 114 in the transmitting device 100 is changed, the user starts the application program for acquiring the information of the communication target and performs the operation for performing the image capturing. I do. The image capturing unit 214 in the receiving device 200 captures an image in accordance with a user operation, and sequentially outputs the image signals within the image capturing angle of view to the control unit 202. The image generation unit 232 in the control unit 202 generates a frame by converting the image signal into digital data each time the image signal from the imaging unit 214 is input. The decoding unit 234 in the control unit 202 acquires, as a candidate region (blinking pattern), a pixel of which brightness is equal to or higher than a predetermined value among the pixels in the image data of the frame (step S101).

When the candidate area exists, the decoding unit 234 acquires the hue value and the lightness value of the candidate area in the frame for each imaging, and determines whether the color plane can be set (step S102). .. Specifically, the decoding unit 234 sets the acquired hue value within a predetermined range (within the red determination area) centered around the red (R) hue reference value and around the green (G) hue reference value. It is determined whether it is within a predetermined range (in the green determination area) or within a predetermined range (in the blue determination area) centered on the hue reference value of blue (B) (step S102).

When the color plane cannot be set (step S102; NO), the decoding unit 234 determines that the candidate area is noise instead of the change area (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 the change area, and the colors (red (R) and green (corresponding to the hue value of the change area, green ( G) or blue (B)) is determined (clustering) (step S103).

Further, the decoding unit 234 determines whether or not the hue value and the lightness value acquired for each image pickup are different from the hue reference value and the lightness 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 lightness reference value (step S104; YES), the decoding unit 234 corrects the hue reference value and the lightness reference value (step S105).

After the hue reference value and the lightness reference value are corrected in step S105, or when it is determined that the hue value and the lightness value acquired for each image pickup in step S104 are not different from the hue reference value and the 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 the 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 deviate from the hue reference value and the lightness reference value, and if they deviate, the hue reference value and the lightness reference value are corrected. As a result, even if the reference values of the hue and lightness of each of the colors of red (R), green (G), and blue (B) deviate from the hue and lightness obtained by imaging, the deviation is eliminated. Color determination can be appropriately performed, and decoding with excellent environmental resistance can be performed.

The present invention is not limited to the above embodiment, and various modifications and applications are possible. For example, in the above-described embodiment, the case where visible light of red (R), green (G), and blue (B) is used for communication has been described, but visible light of another color may be used, Further, light other than visible light such as infrared rays may be used.

Further, the transmission unit 114 in the transmission device 100 may be configured as a part of the display unit, for example.

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

Alternatively, an apparatus having both the function of the receiving apparatus 200 and the function of the transmitting apparatus 100 may be prepared so that both functions can be used properly depending on the situation.

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

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

In the case where the OS (Operating System) shares the above-described functions, or when the OS and the application cooperate with each other, even if only the part other than the OS is stored in the medium and distributed. Well, you may download it.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and the present invention includes the invention described in the claims and an equivalent range thereof. Be done. The inventions described in the initial claims of the present application will be additionally described below.

(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 so as 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. Decryption control means for controlling to
A decoding device comprising:

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

(Appendix 3)
The decoding control means compares the color space information stored in advance as a reference by the decoding means with the color space information included in the color image, and based on the comparison result, the color space included in the color image. 3. The decoding device according to appendix 1 or 2, further comprising a correction unit that corrects information so as to match the color space information that the decoding unit uses as a reference.

(Appendix 4)
The color space is a space in which at least hue and lightness are set as parameters,
4. The decoding device according to appendix 3, wherein the correction means 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 to acquire a color image,
A decoding step of decoding information from a predetermined distance interval on the color space,
The color space information included in the color image acquired in the acquisition step is controlled to match the reference color space information 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
A decoding method comprising:

(Appendix 7)
Computer,
An 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 so as 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. Decryption control means for controlling to
Program to function as.

DESCRIPTION OF SYMBOLS 1... Optical communication system, 100... Transmitting device, 102... Control part, 104... Memory, 110... Encoding/modulating part, 112... Driving part, 114... Transmitting part, 200... Receiving device, 202... Control part, 204... Memory, 206... Operation section, 207... Display section, 208... Wireless communication section, 210... Antenna, 214... Imaging section, 232... Image generation section, 234... Decoding section, 236... Display control section

In order to achieve the above object, the decoding device according to the present invention,
An acquisition unit that acquires a hue value from a change area in which a hue change occurs in a color image that is continuously input in time series ,
Decoding means for decoding from a hue reference value corresponding to the three primary colors in a predetermined color space into a bit data string ,
Decoding control means for correcting the hue reference value corresponding to the hue value so as to match the hue value acquired by the acquisition means, and controlling so as to decode the corrected hue reference value into a bit data string ,
It is characterized by including.

Claims (6)

An acquisition unit that acquires a time series change pattern of the three primary colors in a color image,
Decoding means for decoding into information based on each hue value in the color space of the three primary colors of the change pattern acquired by the acquisition means,
Control to replace each hue value in the color space of the three primary colors of the change pattern acquired by the acquisition unit with each hue value that the decoding unit uses as a reference, to form a time-series change pattern of the replaced hue value. Decoding control means for controlling decoding based on the information,
A decoding device comprising: The decoding control means, among the hue reference values of the three primary colors of the color space information stored in advance, for those having a deviation from the hue value in the color space of the three primary colors of the change pattern acquired by the acquisition means, The decoding device according to claim 1, further comprising a correction unit that performs correction so as to replace an average value of hue values in the color spaces of the three primary colors of the change pattern. The correction unit is further configured to change the change pattern of the lightness reference values of the three primary colors of the color space information stored in advance, which are different from the lightness values of the three primary colors of the change pattern acquired by the acquisition unit. The decoding apparatus according to claim 2, wherein the correction is performed so as to replace the average value of the lightness values of the three primary colors. The decoding device according to claim 1, wherein the acquisition unit includes an imaging unit. An acquisition step of acquiring a time-series change pattern of the three primary colors in a color image,
A decoding step of decoding into information based on each hue value in the color space of the three primary colors of the change pattern acquired in the acquisition step,
Control to replace each hue value in the color space of the three primary colors of the change pattern acquired in the acquisition step with each hue value used as a reference in the decoding step, and the time-series change pattern of the replaced hue value A decoding control step for controlling decoding to information based on
A decoding method comprising: Computer,
An acquisition unit that acquires a time-series change pattern of the three primary colors in a color image,
Decoding means for decoding into information based on each hue value in the color space of the three primary colors of the change pattern acquired by the acquisition means,
Control to replace each hue value in the color space of the three primary colors of the change pattern acquired by the acquisition unit with each hue value that the decoding unit uses as a reference, to form a time-series change pattern of the replaced hue value. Decoding control means for controlling decoding based on the information,
Program to function as.

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