KR102105094B1 - Two-dimensional coding method for visible light communication and apparatus thereof - Google Patents

Abstract

Disclosed is a two-dimensional coding method and apparatus for visible light communication. According to an embodiment, the transmitting apparatus for visible light communication includes an LED array including a plurality of vertical panels, and a controller generating control signals for each of the plurality of vertical panels, wherein the plurality of vertical panels each control the control. Different visible light signals are transmitted based on the signals.

Description

A two-dimensional coding method and apparatus for visible light communication {TWO-DIMENSIONAL CODING METHOD FOR VISIBLE LIGHT COMMUNICATION AND APPARATUS THEREOF}

The following embodiments relate to a two-dimensional coding method and apparatus for visible light communication.

There are two main technologies for optical camera communication (OCC). The first is high-speed OCC using LED arrays and high-speed cameras. As the name suggests, this type of OCC uses an ultra-fast camera to capture thousands of LED array images per second to achieve high data rates. Despite the obvious advantages of high data rates, this technology has disadvantages related to software complexity and especially hardware costs. The second technique is low-speed OCC using low-speed CMOS sensor cameras. Although it has the advantages of simplicity and low cost, the technology has not received much attention from researchers because of its low data transmission rate. More specifically, in a typical OCC using a CMOS sensor camera, the rolling shutter effect of the CMOS sensor is used to create a horizontal black and white band that carries bits 0 and 1 in the image of a single LED. As previously known, typical hardware has a theoretical limit on the data transmission rate of 32 Kbit / s.

A related prior art is Patent Publication No. 10-2008-0093520.

According to an embodiment, the transmitting apparatus for visible light communication includes an LED array including a plurality of vertical panels, wherein the plurality of vertical panels each include a plurality of LEDs; And a controller that generates control signals for each of the plurality of vertical panels, and each of the plurality of vertical panels transmits different visible light signals based on the control signals.

Each of the plurality of vertical panels may be turned on and off asynchronously with each other according to the control signal, and the control signal may include an on / off time point of each of the plurality of vertical panels corresponding to transmission data. .

The plurality of vertical panels may include a first vertical panel and a second vertical panel, and the control signal may include a first control signal corresponding to the first transmission data and a second control signal corresponding to the second transmission data. It may include, the first vertical panel is on / off based on the first control signal to transmit the first transmission data, the second vertical panel is on / based on the second control signal By being off, the second transmission data can be transmitted.

The visible light communication may include optical camera communication using a complementary metal-oxide semiconductor (CMOS) sensor. Different types of stripe patterns based on a rolling shutter mechanism of a complementary metal-oxide semiconductor (CMOS) sensor may be photographed in the image in which the LED array is photographed, corresponding to each of the plurality of vertical panels, The different types of stripe patterns may correspond to different transmission data.

According to an embodiment, a transmission method for visible light communication includes generating control signals for each of a plurality of vertical panels in an LED array, wherein the plurality of vertical panels each include a plurality of LEDs; And transmitting different visible light signals through each of the plurality of vertical panels by controlling the plurality of vertical panels based on the control signal.

1 is a view showing a transmitting apparatus for visible light communication according to an embodiment.
2 is a diagram illustrating a coding method using a rolling shutter mechanism according to an embodiment.
3 is a view showing an image taken through a transmission process and a CMOS sensor using 2D coding according to an embodiment.
4 is a timing diagram showing a control signal according to an embodiment.
5 is an operation flowchart showing a transmission method for visible light communication according to an embodiment.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are exemplified only for the purpose of illustrating the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention These can be implemented in various forms and are not limited to the embodiments described herein.

Embodiments according to the concept of the present invention can be applied to various changes and can have various forms, so that the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosure forms, and includes modifications, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various components, but the components should not be limited by the terms. The above terms are only for the purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, the first component may be referred to as the second component, Similarly, the second component may also be referred to as the first component.

When an element is said to be “connected” or “connected” to another component, it is understood that other components may be directly connected to or connected to other components, but other components may exist in the middle. It should be. On the other hand, when a component is said to be “directly connected” or “directly connected” to another component, it should be understood that no other component exists in the middle. Expressions that describe the relationship between the elements, for example, “between” and “immediately between” or “directly neighboring to” should also be interpreted.

The terminology used herein is only used to describe specific embodiments and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms “include” or “have” are intended to designate the presence of a feature, number, step, action, component, part, or combination thereof as described, one or more other features or numbers, It should be understood that the existence or addition possibilities of steps, actions, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms, such as those defined in a commonly used dictionary, should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined herein. Does not.

The present invention proposes a two-dimensional coding in optical camera communication (OCC) using a CMOS sensor. In general, OCC uses the rolling shutter effect of a CMOS sensor to create horizontal bands that carry information along a dimension of the image. The present invention encodes information in the vertical and horizontal dimensions of an image using a horizontal array composed of multiple vertical panels, instead of using a single LED panel as in the general technique. Compared to the general technology of OCC using CMOS sensor, the complexity of software increases at the same cost according to the present invention, and most importantly, the data rate increases rapidly.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. The same reference numerals in each drawing denote the same members.

1 is a view showing a transmission device for visible light communication according to an embodiment.

Referring to FIG. 1, the transmitting device 100 may include an LED array (light emitting diode array) 110 and a controller 120.

The LED array 110 includes a plurality of vertical panels, such as the vertical panel 111. Each of the plurality of vertical panels includes a plurality of LEDs. As illustrated in FIG. 1, the LED array 110 may have a shape in which the length in the horizontal direction is longer than the length in the vertical direction, and the plurality of vertical panels may be arranged in the horizontal direction within the LED array 110. . Although FIG. 1 shows that there is a certain space between the plurality of vertical panels, the plurality of vertical panels may be continuously arranged without any free space. The plurality of vertical panels may be physically independent panels, or the LED array 110 may be logically divided. That is, a single LED array 110 may be divided by software to define a plurality of vertical panels.

The controller 120 may generate a control signal and control a plurality of vertical panels in the LED array 110 through the control signal. As described in detail below, a complementary metal-oxide semiconductor (CMOS) sensor uses a rolling shutter mechanism for image acquisition. In the CMOS sensor, exposure and data reading are sequentially performed row by row. The two-dimensional coding technique of the present invention utilizes the characteristics of such a CMOS sensor.

When a specific LED array is photographed by a CMOS sensor, as a specific LED array is turned on / off while one frame is generated by the CMOS sensor, a constant stripe pattern may occur in the corresponding frame. Data can be encoded in this stripe pattern. For example, if bit 1 is assigned to the "ON" LED and bit 0 is assigned to the "OFF" LED, the row corresponding to the "ON" LED in the stripe pattern in the captured image is decoded as bit 1, and " It is possible to decode the row corresponding to the OFF "LED to bit 0. Bit 1 may mean logical high, and bit 0 may mean logical low.

Since the LED array 110 includes a plurality of vertical panels, the controller 120 can transmit data through each of the plurality of vertical panels. Each of the plurality of vertical panels may be provided with control signals corresponding to different data, and each of the plurality of vertical panels may independently transmit data according to the control signal. That is, each of the plurality of vertical panels may be turned on / off asynchronously with each other according to a control signal. Therefore, data may be encoded in two dimensions of a vertical dimension and a horizontal dimension through the LED array 110 composed of multiple vertical panels.

2 is a diagram illustrating a coding method using a rolling shutter mechanism according to an embodiment.

로 표시되며, 이는 한 행의 판독 시간과 동일하다. 센서의 다른 행이 서로 다른 시간에 노출되기 때문에, CMOS 센서에 의해 특정 LED 어레이가 촬영될 때, CMOS 센서에 의해 하나의 프레임이 생성되는 동안 특정한 LED 어레이가 온/오프됨에 따라 해당 프레임에는 일정한 스트라이프 패턴이 발생할 수 있다.As mentioned above, CMOS sensors use a rolling shutter mechanism for image acquisition. The exposure and data reading of the CMOS sensor is done row by row in the sensor, and each row of the CMOS sensor is sequentially exposed at different times. The gap between the starting points of the exposure in two successive rows is

Is indicated, which is equal to the read time of one row. Because different rows of sensors are exposed at different times, when a particular LED array is photographed by a CMOS sensor, a certain stripe is assigned to that frame as a particular LED array is turned on / off while one frame is being generated by the CMOS sensor. Patterns can occur.

For example, as shown in FIG. 2, the control signal 210 may sequentially include a logic high bit and a logic low bit, and the LED array 220 may be sequentially turned on / off according to the control signal 210. You can. In this case, the captured image 230 may be obtained by photographing the LED array 220 with the CMOS sensor. The captured image 230 may include a stripe pattern corresponding to the control signal 210. In the stripe pattern, the white horizontal band may be decoded into logical high bits, and the black horizontal band may be decoded into logical low bits. For example, the captured image 230 may be decoded into a bit stream 1010.

The present invention can maximize the data transmission capacity by applying the encoding / decoding technique to each of a plurality of vertical panels. That is, one row in the LED array is divided corresponding to a plurality of vertical panels, where data can be independently encoded. One horizontal band in the stripe pattern is divided into a plurality of data can be encoded in each. Thus, data transmission capacity can be significantly increased compared to single data being encoded in one row of the LED array. Specifically, the data transmission capacity may be multiplied by the number of divided vertical panels.

According to the conventional encoding method, since one bit can be expressed in one row, it can be viewed as one-dimensional coding in the vertical direction. Since the present invention can express a plurality of bits in one row, it can be understood as two-dimensional coding in the vertical and horizontal directions.

3 is a diagram illustrating an image transmitted through a CMOS sensor and a transmission process using 2D coding according to an embodiment.

Referring to FIG. 3, the LED array 310 includes a plurality of vertical panels, such as vertical panels 311, 312, and 313. Each vertical panel is composed of several LED chips that transmit high-frequency signals, and control signals provided to different vertical panels and thus visible light signals transmitted from different vertical panels are different. For example, a first control signal may be provided to the first vertical panel 311, a second control signal to the second vertical panel 312, and a third control signal to the third vertical panel 313. If the number of vertical panels is n, an n-th control signal may be provided to the n-th vertical panel.

Each control signal can correspond to different data. For example, the first control signal may correspond to the first transmission data to be transmitted through the first vertical panel 311, and the second control signal is the second transmission to be transmitted through the second vertical panel 312. Data, and a third control signal may correspond to third transmission data to be transmitted through the third vertical panel 313.

The control signal may include on / off timings of each of the plurality of vertical panels corresponding to the transmission data, and each of the plurality of vertical panels may transmit / receive transmission data by being turned on / off according to the control signal. For example, the first vertical panel 311 may transmit the first transmission data by being turned on / off based on the first control signal, and the second vertical panel 312 may be turned on / off based on the second control signal. The second transmission data can be transmitted by being turned off, and the third vertical panel 313 can transmit the third transmission data by being turned on / off based on the third control signal.

4 is a timing diagram showing a control signal according to an embodiment. Referring to FIG. 4, the control signal includes on / off timings of each of a plurality of vertical panels corresponding to transmission data. For example, the first control signal of FIG. 3 may correspond to the waveform 410, the second control signal of FIG. 3 may correspond to the waveform 420, and the third control signal of FIG. 3 may be the waveform 430 Can respond to. Although three control signals are shown in FIG. 4, the control signals may exist as many as the number of vertical panels. For example, if the number of vertical panels is n as in the previous example, n control signals may also exist. Each vertical panel can transmit different visible light signals based on different control signals.

Referring to FIG. 3 again, when the entire LED array 310 is photographed by a CMOS sensor camera, a plurality of stripe patterns each including a plurality of horizontal bands in the photographed image 320 appears. The stripe pattern 321 corresponds to the vertical panel 311, the stripe pattern 322 corresponds to the vertical panel 312, and the stripe pattern 323 corresponds to the vertical panel 313. The patterns according to the horizontal bands in the stripe patterns 321, 322, and 323 are different. This is because the first control signal, the second control signal, and the third control signal are different. Therefore, different data may be decoded through the stripe patterns 321, 322, and 323.

5 is an operation flowchart illustrating a transmission method for visible light communication according to an embodiment.

Referring to FIG. 5, in step 510, control signals for each of the plurality of vertical panels in the LED array are generated. Each of the plurality of vertical panels includes a plurality of LEDs. The control signal may include on / off timings of each of the plurality of vertical panels corresponding to transmission data, and each of the plurality of vertical panels may be turned on / off asynchronously with each other according to the control signal.

In step 520, different visible light signals are transmitted through each of the plurality of vertical panels by controlling the plurality of vertical panels based on the control signal. For example, the first vertical panel among the plurality of vertical panels transmits the first transmission data by being turned on / off based on the first control signal, and the second vertical panel among the plurality of vertical panels is based on the second control signal. By turning on / off, the second transmission data can be transmitted.

In addition, the above-described matter may be applied to a transmission method for visible light communication, and a detailed description thereof will be omitted.

The device described above may be implemented with hardware components, software components, and / or combinations of hardware components and software components. For example, the devices and components described in the embodiments include, for example, a processor, a controller, an Arithmetic Logic Unit (ALU), a digital signal processor (micro signal processor), a microcomputer, and a field programmable gate array (FPGA). , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions, may be implemented using one or more general purpose computers or special purpose computers. The processing device may run an operating system (OS) and one or more software applications running on the operating system. In addition, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of understanding, a processing device may be described as one being used, but a person having ordinary skill in the art, the processing device may include a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that may include. For example, the processing device may include a plurality of processors or a processor and a controller. In addition, other processing configurations, such as parallel processors, are possible.

The software may include a computer program, code, instruction, or a combination of one or more of these, and configure the processing device to operate as desired, or process independently or collectively You can command the device. Software and / or data may be interpreted by a processing device or to provide instructions or data to a processing device, of any type of machine, component, physical device, virtual device, computer storage medium or device, Or it may be permanently or temporarily embodied in the signal wave being transmitted. The software may be distributed on networked computer systems, and stored or executed in a distributed manner. Software and data may be stored in one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment or may be known and available to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs, DVDs, and magnetic media such as floptical disks. -Hardware devices specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language code that can be executed by a computer using an interpreter, etc., as well as machine language codes made by a compiler. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described by a limited embodiment and drawings, those skilled in the art can make various modifications and variations from the above description. For example, the described techniques are performed in a different order than the described method, and / or the components of the described system, structure, device, circuit, etc. are combined or combined in a different form from the described method, or other components Alternatively, even if replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (10)

In the transmission device for visible light communication,
LED array including a plurality of vertical panels, each of the plurality of vertical panels includes a plurality of LEDs; And
A controller that generates a control signal including on / off timings of each of the plurality of vertical panels based on transmission data
Including,
Each of the plurality of vertical panels is asynchronously turned on / off according to the control signal to transmit different visible light signals,
When the LED array is photographed by the receiving device and an image is generated, stripe patterns of different shapes based on a rolling shutter mechanism of a CMOS sensor corresponding to each of the plurality of vertical panels are photographed in the images, and the different shapes The stripe pattern of corresponding to different transmission data,
Transmitting device. delete delete According to claim 1,
The plurality of vertical panels includes a first vertical panel and a second vertical panel,
The control signal includes a first control signal corresponding to the first transmission data and a second control signal corresponding to the second transmission data,
The first vertical panel transmits the first transmission data by being turned on / off based on the first control signal,
The second vertical panel transmits the second transmission data by being turned on / off based on the second control signal,
Transmitting device. According to claim 1,
The visible light communication includes an optical camera communication using a complementary metal-oxide semiconductor (CMOS) sensor. delete In the transmission method for visible light communication,
Generating a control signal including on / off timing of each of the plurality of vertical panels in the LED array based on the transmission data, wherein the plurality of vertical panels each include a plurality of LEDs; And
Controlling the plurality of vertical panels based on the control signal to transmit different visible light signals through each of the plurality of vertical panels
Including,
Each of the plurality of vertical panels is asynchronously turned on / off according to the control signal to transmit different visible light signals,
When the LED array is photographed by the receiving device and an image is generated, stripe patterns of different shapes based on a rolling shutter mechanism of a CMOS sensor corresponding to each of the plurality of vertical panels are photographed in the images, and the different shapes The stripe pattern of corresponding to different transmission data,
Transmission method. delete delete delete

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