KR102745401B1 - Apparatus and method for optical wireless communication based on fft, m-ary frequency shift keying and full spectrum led - Google Patents

Abstract

According to one embodiment of the present disclosure, an optical signal receiving device includes a full-spectrum camera which receives a full-spectrum optical signal transmitted from a full-spectrum LED to generate an image, at least one processor, and a memory which is electrically connected to the processor and stores at least one code executed by the processor, wherein the memory may store a code which, when executed through the processor, causes the processor to generate an image frame including all of light information of an infrared band, a visible light band, and an ultraviolet band based on a sensor signal of a camera which has photographed a light source including the full-spectrum LED, extract level change information from an area where the light source has been photographed in the image frame to generate an FSK modulation signal, perform a Fourier transform on the FSK modulation signal and then extract a frequency to divide the FSK modulation signal into a plurality of bands, demodulate the FSK modulation signal divided into the plurality of bands using an M-FSK (Mary-Frequency Shift Keying) method based on a preset bit-frequency mapping table and frequency to generate a data stream for each band, and merge the data streams for each band.

Description

{APPARATUS AND METHOD FOR OPTICAL WIRELESS COMMUNICATION BASED ON FFT, M-ARY FREQUENCY SHIFT KEYING AND FULL SPECTRUM LED}

The present disclosure relates to a device and method for transmitting a signal using full spectrum LED and optical wireless communication based on M-FSK (M-ary Frequency Shift Keying).

The contents described below are described only for the purpose of providing background information related to embodiments of the present invention, and the contents described do not necessarily constitute prior art.

Recently, Visible Light Communication (VLC) technology, a wireless communication technology that adds communication functions to visible light wavelengths, is being actively studied by utilizing the infrastructure in which lighting such as incandescent bulbs and fluorescent lamps are being replaced with semiconductor LED (Light Emitting Diode) lighting.

Additionally, optical camera communication (OCC) technology is being developed to demodulate visible light communication signals received using cameras mounted on user devices such as general smartphones and car cameras.

The camera mounted on the user device can capture light sources using either a global shutter or a rolling shutter method.

Prior art 1 discloses a technology for communicating using a camera-based M-FSK method based on a rolling-shutter camera. However, since the general M-FSK method can only use one frequency at the same time from one light source, it is difficult to transmit high-speed data.

Prior art 2 discloses a technology for communicating by the CSK (Color Shift Keying) method, but the general CSK method has a problem in that there is a high probability of error due to the recognition of colors that depend on the receiving environment in the receiving device, and a separate technology is required to recover this. In addition, a CSK signal receiving device based on a photo detector has a problem in that it is difficult to recognize a signal due to the influence of ambient light when the distance from the transmitting device increases.

Prior art 1: Korean Patent Publication No. 10-165184 (registered on August 22, 2016) Prior art 2: Korean Patent Publication No. 10-1728518 (registered on April 13, 2017)

One embodiment of the present disclosure provides a device and method capable of transmitting data at high speed in optical wireless communication based on full spectrum LEDs.

Another embodiment of the present disclosure provides an apparatus and method capable of easily demodulating a transmitted M-FSK modulated optical signal based on a full spectrum LED.

Another embodiment of the present disclosure provides a device and method capable of stably transmitting data based on Walsh coding in optical wireless communication based on full spectrum LEDs.

The purpose of the present invention is not limited to the tasks mentioned above, and other purposes and advantages of the present invention that are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. In addition, it will be understood that the purposes and advantages of the present invention can be realized by the means and combinations thereof indicated in the claims.

According to one embodiment of the present disclosure, an optical signal receiving method is provided, in which a processor of an optical signal receiving device including a rolling shutter-based camera capable of photographing a full-spectrum band performs at least a part of each step, the method including: a step of generating an image frame including information of an infrared band, a visible light band, and an ultraviolet band based on a sensor signal of a camera that photographs a light source including a full-spectrum LED; a step of extracting level change information from an area in the image frame where the light source is photographed to generate an FSK modulation signal; a step of extracting a frequency after Fourier transforming the FSK modulation signal to divide it into a plurality of bands; and a step of demodulating the FSK modulation signal divided into the plurality of bands using a Mary-Frequency Shift Keying (M-FSK) method based on a preset bit-frequency mapping table and frequency to generate a data stream for each band, and a step of merging the data streams for each band.

According to one embodiment of the present disclosure, an optical signal receiving device includes a full-spectrum camera which receives a full-spectrum optical signal transmitted from a full-spectrum LED to generate an image, at least one processor, and a memory which is electrically connected to the processor and stores at least one code executed by the processor, wherein the memory may store a code which, when executed through the processor, causes the processor to generate an image frame including all of light information of an infrared band, a visible light band, and an ultraviolet band based on a sensor signal of a camera which has photographed a light source including the full-spectrum LED, extract level change information from an area where the light source has been photographed in the image frame to generate an FSK modulation signal, perform a Fourier transform on the FSK modulation signal and then extract a frequency to divide the FSK modulation signal into a plurality of bands, demodulate the FSK modulation signal divided into the plurality of bands using an M-FSK (Mary-Frequency Shift Keying) method based on a preset bit-frequency mapping table and frequency to generate a data stream for each band, and merge the data streams for each band.

A signal transmission device and method according to an embodiment of the present disclosure can improve a data transmission speed in optical wireless communication by transmitting an M-FSK modulated signal by utilizing the entire band of an infrared band, a visible light band, and an ultraviolet band.

A signal transmission device and method according to an embodiment of the present disclosure can easily demodulate an M-FSK modulated signal transmitted through an optical communication technology in a full spectrum band.

A signal transmission device and method according to an embodiment of the present disclosure can stably transmit an M-FSK modulated signal based on a Walsh code over the full spectrum band of optical wireless communication.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

FIG. 1 is a schematic diagram illustrating communication of a signal transmitting device and a signal receiving device of full spectrum optical wireless communication according to one embodiment of the present disclosure.
FIG. 2 is a block diagram showing the configuration of a signal transmission device for full spectrum optical wireless communication according to one embodiment of the present disclosure.
FIG. 3 is a diagram illustrating one embodiment of a packet of a data stream according to one embodiment of the present disclosure.
FIG. 4 is a diagram illustrating frequencies used for M-FSK modulation for full spectrum optical wireless communication according to one embodiment of the present disclosure.
FIG. 5 is a diagram for explaining a method for generating an optical modulation signal based on an M-FSK modulation signal in a full spectrum optical wireless communication according to one embodiment of the present disclosure.
FIG. 6 is a flowchart illustrating a signal transmission method of full spectrum optical wireless communication according to one embodiment of the present disclosure.
FIG. 7 is a block diagram showing the configuration of a signal receiving device for full spectrum optical wireless communication according to one embodiment of the present disclosure.
FIG. 8 is a flowchart illustrating a method for demodulating an optical signal received via full spectrum optical wireless communication according to one embodiment of the present disclosure.
FIGS. 9 and 10 are diagrams illustrating an example of demodulating an optical signal received by full spectrum optical wireless communication according to an embodiment of the present disclosure.
FIG. 11 is a block diagram showing the configuration of a signal transmission device for full spectrum optical wireless communication according to another embodiment of the present disclosure.
FIG. 12 is a flowchart illustrating a signal transmission method of full spectrum optical wireless communication according to another embodiment of the present disclosure.
FIG. 13 is a block diagram showing the configuration of a signal receiving device for full spectrum optical wireless communication according to another embodiment of the present disclosure.
FIG. 14 is a flowchart illustrating a signal receiving method of full spectrum optical wireless communication according to another embodiment of the present disclosure.
FIG. 15 is a block diagram showing the configuration of a signal receiving device for full spectrum optical wireless communication based on Fourier transform according to another embodiment of the present disclosure.
FIG. 16 is a flowchart illustrating a signal receiving method of full spectrum optical wireless communication based on Fourier transform according to another embodiment of the present disclosure.
FIG. 17 is a block diagram showing the configuration of a signal receiving device for full spectrum optical wireless communication based on a band pass filter according to another embodiment of the present disclosure.
FIG. 18 is a diagram illustrating a method for demodulating a received optical signal of full spectrum optical wireless communication based on a band pass filter according to another embodiment of the present disclosure.
FIG. 19 is a flowchart illustrating a signal receiving method of full spectrum optical wireless communication based on a band pass filter according to another embodiment of the present disclosure.

Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing symbols, identical or similar components will be given the same reference numerals and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not have distinct meanings or roles in themselves. In addition, when describing embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

When it is said that a component is "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components in between. On the other hand, when it is said that a component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

Referring to FIG. 1, communication between a signal transmitting device and a signal receiving device of optical wireless communication based on a full spectrum according to one embodiment of the present disclosure is described.

Referring to FIG. 1, the signal transmission device (100) may be configured to receive data, modulate it based on M-FSK, modulate it again into an optical signal including an infrared (IR) band, a visible light (VL) band, and an ultraviolet (UV) band, and transmit the modulated transmission signal as a full-spectrum optical signal through a light source unit (130) including a full-spectrum LED that supports the spectrums of the infrared band, the visible light band, and the infrared band. As described with reference to FIGS. 2 to 5, the signal transmission device (100) may separate the input data into a plurality of channels corresponding to the corresponding bands, input the same, and then modulate each channel in order to generate an M-FSK (M-ary Frequency Shift Keying) modulation signal for transmitting an optical modulation signal in the infrared band, the visible light band, and the ultraviolet light band, respectively.

In this specification, unless otherwise stated, the transmitted and received optical signals are described as full spectrum optical signals including the spectrum of the infrared band, the visible light band, and the infrared band.

The signal transmission device (100) can modulate data in the M-FSK manner of multiple bands by separating the data into three channels corresponding to optical modulation signals of the infrared band, the visible light band, and the ultraviolet band, and then modulating data for each channel in the M-FSK manner.

The signal transmission device (100) can generate an optical modulation signal based on a signal synthesized by modulating multiple FSK modulation signals respectively in three channels. This will be described in detail below based on FIG. 5.

The signal transmission device (100) can transmit the light modulation signal as an optical signal of a full spectrum band by controlling a light source unit (130) including a full spectrum LED to emit light in a full spectrum band according to an optical modulation signal.

A signal receiving device (200) generates a pulse-shaped FSK modulation signal (220) from a strip image frame, such as that shown in FIG. 10, based on a sensor signal of a rolling shutter-based camera (210) capable of sensing the entire full spectrum region photographed by a light source unit (130) including a full spectrum LED, and an M-FSK decoder (230) can generate data by extracting a frequency from the FSK modulation signal and then demodulating it based on M-FSK.

The camera (210) may be a plurality of cameras including an infrared band camera, a visible light band camera and an ultraviolet band camera, which can output sensor signals and generate image frames in an infrared band, a visible light band and an ultraviolet band, respectively, or a single camera that senses the infrared band, the visible light band and the ultraviolet band in separate sensor areas at the same time, or a single camera that senses the infrared band, the visible light band and the ultraviolet band in the same sensor area at different times through filter processing or the like.

The signal receiving device (200) can determine a light source area in an image frame based on each sensor signal of an infrared band, a visible light band, and an ultraviolet light band, and extract an FSK modulation signal from the image frame of the light source area. The image frame can be a strip-shaped image frame in which the light modulation signal of the light source (130) is sensed by each sensor of the infrared band, the visible light band, and the ultraviolet light band.

The signal receiving device (200) can generate an FSK modulation signal based on a strip image frame, and extract a frequency of the FSK modulation signal by considering the length of an on-level or an off-level of each portion corresponding to a preamble and a payload and the shutter speed of a camera. The signal receiving device (200) can demodulate the FSK modulation signal in an M-FSK manner based on the extracted frequency and a preset bit-frequency mapping table, and generate a data stream.

Referring to FIG. 2, a configuration of a signal transmission device according to an embodiment of the present disclosure is described.

Referring to FIG. 2, a signal transmission device (100) may include a modulation unit (110) including a full spectrum M-FSK encoder, a serial-to-parallel (S2P) converter, a preamble insertion unit, a full spectrum modulator (113), and a control unit (120) that controls a light source unit (130) that is a communication channel including a full spectrum LED light source, and may include a clock generator that generates a clock signal.

In one embodiment, the data stream may be a packet that modulates a signal to be transmitted into a binary signal. The modulation unit may include an FEC (Forward Error Correction) encoder, a preamble insertion unit, and a binary modulation unit that modulates input data into a binary signal.

In one embodiment, the full spectrum M-FSK modulator (110) can modulate a data stream in which a binary signal is configured in the form of a packet into a full spectrum data signal. In the following, it is assumed that the full spectrum M-FSK modulator (110) modulates a data stream which is a binary signal into a full spectrum data signal.

In one embodiment, the full spectrum M-FSK modulation unit (110) may generate a binary data signal by line coding a binary signal. Line coding may be a modulation that outputs input bit 0 as 00 and outputs input bit 1 as 01.

A data stream can be a packet containing a payload corresponding to the data to be transmitted and a preamble corresponding to the header.

In one embodiment, the signal transmission device (100) may include a sequence number in the packet, and the sequence number may be assigned as a consecutive number for consecutive data packets, and the sequence number may be used by repeating a certain number (which may be bits) in sequence. For example, the sequence number may be 00 for the first packet, 01 for the second packet, and 00 again for the third packet. The signal reception device (200) may determine whether the packet is duplicated through the sequence number.

Referring to FIG. 3, a portion of a packet structure input to a full spectrum M-FSK modulation unit (110) according to one embodiment of the present disclosure is described. In another embodiment, the full spectrum M-FSK modulation unit (110) may convert an input data signal into a portion of a packet such as FIG. 3.

The packets converted from the input data signal may include multiple data packets (i-1, i, i+1).

Each of the plurality of data packets (i-1, i, i+1) may include a plurality of data sub-packets (e.g., data packet (i) may include data sub-packets (i1, i2, i3), and each data sub-packet may include a payload composed of information bits corresponding to a portion of input data).

In one embodiment, to prevent packet loss due to variable frame rate of the receiving camera, multiple data subpackets included in one data packet may include the same payload consisting of the same information bits. That is, the same payload may be transmitted to the signal receiving device (200) in a redundant manner.

A rolling shutter-based camera of the signal receiving device (200) sequentially captures multiple shots of the flashing of a full-spectrum LED light source at different times, and stores each captured signal in one column or row of an image sensor to generate a strip-shaped image frame. At this time, the frame rate of the camera may be variable or lower than the data packet transmission rate depending on the settings of the device, etc. Therefore, the signal transmitting device (100) may configure a data packet to include data subpackets including the same payload repeatedly in order to prevent packet reception omission due to the frame rate limit of the rolling camera. That is, the data subpackets (i1, i2, i3) may include the same payload.

In one embodiment, in order to detect packet loss or distinguish duplicate packets in the signal receiving device (200), the signal transmitting device (100) may assign a sequence number to each data packet or data subpacket, and the sequence number may be assigned as a consecutive number for consecutive data packets.

In one embodiment, each data subpacket (i1, i2, i3) may contain the same payload, which is a sequence number of the corresponding data packet (i) and information bits assigned to the corresponding data packet (i).

In one embodiment, the sequence number may be inserted into the front of the packet, or in another embodiment, may be inserted into both the front and back of the packet. When the sequence number is inserted into both the front and back of the packet, the signal receiving device (200) may, when it finds one preamble in one captured image frame, configure the packet by forward decoding and backward decoding by considering the sequence numbers before and after the preamble.

In one embodiment, a modified packet or data subpacket may include a header portion in the preamble that includes meta information such as the packet size.

In another embodiment, the preamble may be a bit code that is known in advance to the signal transmitting device and the signal receiving device as a bit code that indicates the start of the packet (Start Frame: SF).

In another embodiment, the signal transmission device (100) may include a Forward Error Correction (FEC) encoder and an Ab bit (asynchronous bits) insertion unit. The preamble may include Ab bits.

The full spectrum M-FSK modulation unit (110) of the signal transmission device (100) can divide at least a portion of a packet in serial form or a packet with a preamble inserted into three channels (PIR, PVL, PUV) corresponding to optical modulation signals of an infrared band, a visible light band, and an ultraviolet band, and then modulate each channel using the M-FSK method.

For example, if the bit code of the payload of the packet is '00 01 10', the signal transmission device (100) can separate the bit code '00 01 10' of the payload into three channels for each fixed number of bits, and then separate them into '00', '01', and '10', respectively, and then modulate each separated bit code using the M-FSK method.

In one embodiment, the preamble may be M-FSK modulated for each channel.

Referring to FIG. 4, a method of modulating a full spectrum M-FSK modulation unit (110) according to an embodiment of the present disclosure by modulating a bit code input for each channel based on a bit frequency mapping table of preset different frequency bands is described.

The full spectrum M-FSK modulation unit (110) can map the bit code input for each channel to a frequency based on a table such as <Table 1> below.

The columns IR, VL, and UV in <Table 1> represent M-FSK modulation channels corresponding to optical modulation signals in the infrared band, visible light band, and ultraviolet band.

<Table 1> shows that the two preambles can be mapped to different frequencies in three channels corresponding to optical modulation signals in the infrared band, visible light band, and ultraviolet band. The examples below are explained on the premise that the two preambles are mapped to different frequencies in three channels.

The band of each frequency mapped to the bit code of the preamble and payload can be as shown in Fig. 4 (a).

In one embodiment, the frequencies (f1, f2, f3) mapped to preamble 1 may be the frequencies of the lowest band (the lowest magnitude) in each bit-frequency mapping table of the frequency band allocated to each channel, and the frequencies (f1+5delta, f2+5delta, f3+5delta) mapped to preamble 2 may be the frequencies of the highest band (the largest magnitude). In addition, the bit code of the payload may be a frequency located with an equal band interval between the lowest band frequency and the highest band frequency in the bit-frequency mapping table of each channel, that is, the frequencies mapped to preamble 1 (f1, f2, f3, f4, referred to as base frequencies hereinafter) and the frequencies mapped to preamble 2 (f1+5delta, f2+5delta, f3+5delta). In Fig. 4, the frequencies mapped to the bit codes of the payload are illustrated as four for each channel, but it will be understood by those skilled in the art that the number of basic frequencies mapped to the bit codes of the payload can be changed depending on the number of bit codes to be modulated and the bands of frequencies mapped to preamble 1 and preamble 2. The frequency used for M-FSK modulation in each channel can be understood as the on/off frequency (optical clocking rate) of the infrared band, visible light band, and ultraviolet band of the optical modulation signal finally transmitted.

Let's go into more detail about the frequencies that map to bitcode.

As can be seen in <Table 1>, the bit codes of the preamble and payload are mapped to different frequencies of different bands when input to different channels even if they are the same bit codes. That is, the bit code input to the channel corresponding to the optical modulation signal of the infrared band is mapped to f1 to f1+5delta, and the bit codes input to other channels are also mapped to the frequencies (f2 to f2+5delta) and frequencies (f3 to f3+5delta) of different frequency bands, respectively. The frequencies of each channel may differ by at least 10 times from the frequencies of other channels. This can be applied to all embodiments disclosed in the present specification.

That is, even if the same bit code is used, it can be mapped to different frequencies in different bands, as can be seen in the frequency bands in Fig. 4.

Due to this, even when the same bit code is repeated in the payload (for example, when the same bit code separated from the bit code '01 01 01' is input separately into three channels and bit frequency mapped), the same bit codes input into each channel are respectively mapped to frequencies of different frequency bands, so that the signal receiving device (200) can check whether the same bit code is repeated when demodulating it. In addition, when each modulation signal is finally transmitted as an optical modulation signal, the difference in frequency bands is very large in the case of the infrared band, the visible light band, and the ultraviolet band, so that the possibility of interference is also low. Therefore, even when the signal receiving device (200) demodulates using the M-FSK method based on the strip image, there is an advantage in that it can safely demodulate the packet. In addition, since a total of 6 bits can be transmitted at one time, there is an effect of improving the transmission speed.

In one embodiment, the frequencies of three channels for M-FSK modulation corresponding to optical modulation signals of an infrared band, a visible light band, and an ultraviolet band may differ from each other by at least 10 times for each channel. For example, f2 may be at least 10 times greater than f1, and f3 may be at least 10 times greater than f2. Accordingly, the accuracy of the M-FSK demodulation result in different channels of the signal receiving device (200) may be improved.

In one embodiment, when transmitting an optical modulation signal that modulates data, the signal transmission device (100) may first transmit an optical signal that has converted a preamble.

Accordingly, the signal receiving device (200) can determine the band of the fundamental frequency corresponding to the bit code of each payload of packets corresponding to optical modulation signals of the infrared band, the visible light band, and the ultraviolet band by demodulating the preamble from the received optical signal and extracting the corresponding frequency. For example, the signal receiving device (200) can determine the band of the frequency corresponding to the bit code of each payload by evenly dividing the bands of frequencies (f1, f1+5delta) extracted by demodulating the preamble of the infrared band image frame into a pre-known number.

That is, the signal transmission device (100) transmits an optical modulation signal modulated with an FSK modulation signal to which the frequency of the lowest band and the frequency of the highest band are mapped for each band, and then transmits an optical modulation signal modulated based on the payload, so that even if the signal transmission device (100) modulates in the M-FSK manner by changing the frequency band of the bit frequency mapping table, the signal reception device (200) can determine each frequency to be mapped to the bit code of the bit frequency mapping table of each band without receiving the table separately.

After determining the fundamental frequency, the signal receiving device (200) can determine the frequencies at positions spaced apart from each fundamental frequency by a preset frequency (Δf, delta) as the frequency of the bit code for M-FSK modulation corresponding to the optical modulation signal of each band.

Referring to FIG. 5, a method of modulating an FSK modulation signal (510, 520, 530) output for each channel into a full spectrum optical modulation signal by a full spectrum modulator (113) according to an embodiment of the present disclosure is described.

Figure 5 describes a full spectrum modulator (113) for the case where an M-FSK encoder M-FSK modulates the preamble for each channel.

Fig. 5 shows an example of a case where multiple FSK modulation signals are synthesized as a result of bit frequency mapping by separately inputting the bit code '10 01 00' of the payload to three channels of different frequency bands, respectively, to generate an optical modulation signal having optical characteristics of the infrared band, the visible light band, and the ultraviolet band. The form of the pulse frequency of Fig. 5 is a schematic explanation, and the interval and frequency size of the pulses in the drawing are unrelated.

A full spectrum modulator (113) can generate parameters (voltage signals, etc.) for controlling a full spectrum LED suitable for each band based on the frequency of each channel at the same position on the time axis in the FSK modulation signal (510, 520, 530) modulated in each channel.

For example, the light modulation signal (541) may be a full-spectrum LED that emits light based on a composite parameter determined by synthesizing parameters of an infrared band, a visible light band, and an ultraviolet light band corresponding to the frequencies f1, f2, and f3 of the FSK modulation signal (which may be a signal modulating preamble 1) of each channel at the same time position of the FSK modulation signal (510, 520, 530) for each channel.

Similarly, the optical modulation signal (543) may be an optical modulation signal of a full spectrum LED corresponding to the frequencies f1+5delta, f2+5delta, and f3+5delta of the FSK modulation signal (which may be a signal modulating preamble 2) of the same time position of the FSK modulation signal (510, 520, and 530) for each channel, and the optical modulation signal (545) may be an optical modulation signal of a full spectrum LED corresponding to f1+3delta, f2+2delta, and f3+delta of the FSK modulation signal of the same time position of the FSK modulation signal (510, 520, and 530) for each channel.

That is, the signal transmission device (100) can determine parameters of the infrared band, the visible light band, and the ultraviolet band according to the frequencies of the FSK modulation signals of the same position of the FSK modulation signals (510, 520, 530) for each channel and synthesize them to generate an optical modulation signal. Therefore, the optical modulation signal finally transmitted through the light source (130) including the full-spectrum LED is an optical modulation signal having optical characteristics of the infrared band, the visible light band, and the ultraviolet band.

The control unit (120) of the signal transmission device (100) can transmit the light modulation signal as a full spectrum light signal by controlling the light emission of the full spectrum LED of the light source unit (130) based on the generated light modulation signal.

In Fig. 5, the emission (541, 543, 545) of the full spectrum LED at each time zone is displayed as being the same at a certain time zone, but since the frequencies of the FSK modulation signals of each channel are different, the emission of the full spectrum LED may be different at each time zone.

A signal transmission method of a signal transmission device according to an embodiment of the present disclosure is described with reference to FIG. 6.

A signal transmission device can receive a packet in the form of a binary signal or can receive a transmission signal and convert it into a packet in the form of a binary signal (S110).

A signal transmission device may separate at least a portion of a packet into a predetermined number of bits and input them into a plurality of channels corresponding to optical modulation signals of an infrared band, a visible light band, and an ultraviolet band, and may generate an FSK modulation signal for each channel based on a preset bit frequency mapping table corresponding to each channel, based on the bit codes input for each channel (S120). At this time, the frequencies mapped to the bit codes for each channel may be as described in <Table 1> above, and the frequencies mapped for each channel may differ by 10 times or more.

The signal transmission device can generate parameters (voltage signals, etc.) suitable for each band for controlling a full spectrum LED based on the frequency of the FSK modulation signal of each channel at the same position on the time axis from the FSK modulation signal in the form of a pulse wave generated for each channel, and synthesize them (S130).

The optical modulation signal may be an electrical signal or command for controlling the full spectrum LED to emit light appropriately corresponding to each band of a desired infrared band, visible light band, and ultraviolet band, and the signal transmission device may control the full spectrum LED according to the generated optical modulation signal to transmit an optical signal of a full spectrum band (S140).

Referring to FIG. 7, a configuration of a signal receiving device (200) based on a full spectrum according to an embodiment of the present disclosure is described.

The signal receiving device (200) may include a rolling camera (210) that generates an image frame based on a signal acquired from an image sensor in a rolling shutter manner that receives a full-spectrum optical signal, a modulation signal generating unit (not shown) that determines an area in which a full-spectrum LED is photographed in the image frame and then extracts pulse level (ON/OFF) information based on a strip-shaped image of the area to generate an FSK modulation signal, a multiplier (220) that synthesizes carrier frequencies of the infrared band, the visible light band, and the ultraviolet band into FSK modulation signals of the infrared band, the visible light band, and the ultraviolet band, respectively, a preamble detector (240) that separates preambles of the infrared band, the visible light band, and the ultraviolet band from the FSK modulation signal and determines the frequency of the preamble, and a full-spectrum M-FSK decoder (230) that demodulates the FSK modulation signal in an M-FSK (M-ary Frequency Shift Keying) manner based on the frequency of the preamble and a bit-frequency mapping table to generate a data stream.

A signal receiving method of a signal receiving device (200) according to an embodiment of the present disclosure will be described with reference to FIGS. 8 to 10.

A rolling shutter-based full-spectrum camera (hereinafter referred to as the “rolling camera”) sequentially captures multiple shots of the blinking of a full-spectrum LED light source at different times, and stores each captured signal in a column or row of an image sensor to generate an image frame (S210). The rolling camera sequentially exposes each row or column of the image sensor, so that a signal value corresponding to the light of the LED light source can be acquired according to the blinking of the full-spectrum LED light source in a column or row of the image sensor of the rolling camera. As described with reference to FIG. 1, the rolling camera may be a plurality of cameras including an infrared band camera, a visible-light band camera, and an ultraviolet-light band camera, which can output sensor signals in an infrared band, a visible-light band, and an ultraviolet-light band, respectively, and generate an image frame, or a single camera that senses the infrared band, the visible-light band, and the ultraviolet band at the same time in each of the divided sensor regions, or a single camera that senses the infrared band, the visible-light band, and the ultraviolet band at different times in the same sensor region through filter processing, etc.

The signal receiving device (200) can generate an infrared band image frame, a visible light band image frame, and an ultraviolet band image frame in a strip shape, such as in FIG. 10, based on a signal from a sensor that has captured a full spectrum LED (S210).

A rolling camera sequentially captures multiple shots of the blinking of an LED light source at different times, and stores each captured signal in a column or row of an image sensor to generate an image frame. By sequentially exposing each row or column of the image sensor, a signal value corresponding to the brightness of the LED light source can be acquired according to the blinking of the LED light source in one column or row of the image sensor of the rolling camera. The rolling camera can generate image frames in an infrared band, a visible light band, and an ultraviolet band, respectively. In the description below, it is assumed and explained that a plurality of cameras including a rolling shutter-based infrared band camera, a visible light band camera, and an ultraviolet band camera sequentially expose each row of the image sensor to generate a strip-shaped image frame.

A full spectrum LED light source includes light components of an infrared band, a visible light band, and an ultraviolet band, and a plurality of optical signals to be transmitted by a signal transmission device in each band are transmitted as light of a specific frequency of each band. Accordingly, a rolling shutter-based infrared band camera, a visible light band camera, and an ultraviolet band camera can generate image frames in the infrared band, the visible light band, and the ultraviolet band, respectively. Each image frame includes different information modulated by an M-FSK method in a plurality of different channels of a signal transmission device (100).

The signal receiving device (200) can generate an FSK modulation signal from a strip image frame such as Fig. 10 of an area where a full spectrum LED is photographed (S220). The FSK modulation signal can be on or off values extracted from each row or column of an area where a full spectrum LED is photographed. For example, an FSK modulation signal (810) such as Fig. 9 can be generated from an image frame of an infrared band.

In one embodiment, the signal receiving device (200) can synthesize the FSK modulation signal of each band by multiplying it by a synthesis frequency related to the fundamental frequency (f1, f2, f3) used by the signal transmitting device (100) for each channel. For example, the FSK modulation signal of the infrared band image frame can be multiplied by a signal having a synthesis frequency of 2 x f1 to 2 x (f1+5delta), the FSK modulation signal of the visible light band image frame can be multiplied by a signal having a synthesis frequency of 2 x f2 to 2 x (f2+5delta), and the FSK modulation signal of the ultraviolet band image frame can be multiplied by a signal having a synthesis frequency of 2 x f3 to 2 x (f3+5delta). Since signals of different bands may be mixed in each camera, interference can be reduced by multiplying the synthesis frequency signal.

In one embodiment, the signal receiving device (200) can determine the band of frequencies corresponding to the preamble by separating a signal corresponding to the preamble from the FSK modulation signal, converting it into each frequency domain, and extracting the frequency. That is, even if the signal receiving device (200) does not know the fundamental frequency of each band, the frequencies corresponding to the payload can be determined by extracting the band of frequencies corresponding to the preamble from the FSK modulation signal of each band.

Figure 9 is an example that only includes a preamble indicating the frequency of each band, and other information such as a sequence number may also be additionally included.

The signal receiving device (200) can detect a band of frequencies corresponding to each bit code used for demodulation of the payload and determine the frequencies at positions where the interval between two frequency bands of the preambles of each band is divided by a preset number of equal parts as the frequencies corresponding to each bit code.

The signal receiving device (200) can extract the frequency of the FSK modulation signal (810) based on the shutter speed and the number of pixels corresponding to the on-level (or off-level) of the FSK modulation signal (810) (S230).

For example, referring to FIG. 10, the strip image frames of the infrared band, the visible light band, and the ultraviolet band generated by the infrared band camera, the visible light band camera, and the ultraviolet band camera, respectively, from the full spectrum LED light source may be as shown in FIG. 10, and the width (number of pixels) of the column (or row) corresponding to the ON of the full spectrum LED light source may be different as d1, d2, and d3 for each frequency band. The signal receiving device (200) may determine the frequency of the FSK modulation signal by considering d1, d2, d3 and the shutter speed of each camera.

The signal receiving device (200) can demodulate the FSK modulation signal (810) using the M-FSK (M-ary Frequency Shift Keying) method based on a preset bit-frequency mapping table and a frequency extracted from it, and can generate a data stream by configuring it as a payload of another preamble or packet. The data stream can be a packet as described above.

The full spectrum M-FSK decoder (230) can demodulate the FSK modulation signal (810) in the M-FSK manner using the table of <Table 1> described above to determine the corresponding bit code. As described above, different frequencies in different frequency bands can be mapped to the same bit code and transmitted as an optical modulation signal including an infrared band, a visible light band, and an ultraviolet band. Therefore, there is an effect of being able to achieve a data transmission rate three times higher than that of a general visible light communication-based optical wireless communication technology.

Referring to FIG. 11, the configuration of a signal transmission device (100b) according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description.

Referring to FIG. 11, a signal transmission device (100b) may include a modulation unit (110b) including a full spectrum M-FSK encoder, a serial-to-parallel (S2P) converter, a preamble insertion unit, a full spectrum modulator (113b), and a control unit (120b) that controls a light source unit (130b) that is a communication channel including a full spectrum LED light source, and may include a clock generator that generates a clock signal.

In one embodiment, the signal transmission device (100b) may encode (spread) a data stream using a Walsh code before the data stream is input to the FSK encoder, unlike the signal transmission device (100) described with reference to FIG. 2. In this case, a data stream in the form of a packet including a payload and a preamble may be Walsh-encoded.

In one embodiment, the Walsh encoder (111b) may separate the data stream into a plurality of channels corresponding to optical modulation signals of an infrared band, a visible light band, and an ultraviolet band, and multiply each of the separated data streams by a separate Walsh code.

Walsh codes (also known as Walsh-Hadamard codes) are a set of orthogonal codes used to separate users in the downlink (DL) channel of a CDMA system, but have never been applied in optical-based wireless communication technologies. This is because conventional optical-based wireless communication technologies cannot transmit high-speed data since they can use only one frequency at the same time from one light source, that is, they cannot transmit multiple bit codes on different channels, and thus, ordinary technicians have not felt the need to apply Walsh codes. In contrast, an embodiment of the present invention can transmit multiple bit codes on the basis of frequencies in different bands, and thus, the robustness of data transmission can be improved by applying Walsh codes.

The code orthogonality between two codes W_i and W_j of Walsh codes is defined as follows.

These Walsh codes can be generated repeatedly multiple times, and the method of generating Walsh codes is known in the art, so a detailed description is omitted.

The signal transmission device (100b) modulates the Walsh coded data stream output from the Walsh encoder (111b) by mapping the frequencies of different bands of the channels corresponding to optical modulation signals of the infrared band, visible light band, and ultraviolet band to the bit codes of the data stream in the M-FSK manner, thereby generating an FSK modulation signal.

Referring to FIG. 12, a signal transmission method (S100b) of a signal transmission device (100b) according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description.

The signal transmission device (100b) can receive a packet in the form of a binary signal or can receive a transmission signal and convert it into a packet in the form of a binary signal (S110b).

A signal transmission device (100b) can separate a packet-shaped data stream into a plurality of channels, each corresponding to an infrared band, a visible light band, and an ultraviolet band, at least part of the data stream, and generate a Walsh modulation signal by multiplying the data stream separated by each channel by a separate Walsh code (S120b).

The signal transmission device (100b) can generate an FSK modulation signal for each channel corresponding to an optical modulation signal of an infrared band, a visible light band, and an ultraviolet band based on a bit frequency mapping table such as <Table 1> that corresponds to the bit codes of the Walsh modulation signal input for each channel, an infrared band, a visible light band, and an ultraviolet light band (S130b).

The signal transmission device (100b) can generate an optical modulation signal such as a parameter (voltage signal, etc.) suitable for each band for controlling a full spectrum LED based on the frequency of the FSK modulation signal of each channel at the same position on the time axis from the pulse wave type FSK modulation signal generated for each channel, and synthesize the same (S140b).

The optical modulation signal may be an electrical signal or command for controlling the full spectrum LED to emit light appropriately corresponding to each band of a desired infrared band, visible light band, and ultraviolet band, and the signal transmission device (100b) may control the full spectrum LED according to the generated optical modulation signal to transmit an optical signal of a full spectrum band (S150b).

Referring to FIG. 13, a configuration of a signal receiving device (200b) based on a full spectrum according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description.

The signal receiving device (200b) includes a rolling camera (210b) that generates an image frame based on a signal acquired from an image sensor in a rolling shutter manner that receives a full-spectrum optical signal, a modulation signal generating unit (not shown) that determines an area in which a full-spectrum LED is photographed in the image frame and then extracts pulse level (ON/OFF) information based on a strip-shaped image of the area to generate an FSK modulation signal, an M-FSK decoder that demodulates an FSK modulation signal generated from an optical modulation signal of an infrared band, a visible light band, and an ultraviolet band based on an M-FSK method for each channel, a Walsh decoder (220b) that performs Walsh decoding on a data stream (FSK demodulated signal) demodulated from the FSK modulation signal and generates a final data stream, a preamble detection unit (240b) that separates a preamble for each channel from the FSK modulation signal and determines the frequency of the preamble, and a full-spectrum M-FSK decoder that demodulates an FSK modulation signal in the M-FSK method based on the frequency of the preamble and a bit-frequency mapping table to generate a data stream. Can be.

The rolling camera (210b) of the signal receiving device (200b) may include an infrared band filter, a visible light band filter, and an ultraviolet band filter, and may generate an infrared image frame, a visible light band image frame, and an ultraviolet band image frame based on the infrared band filter, the visible light band filter, and the ultraviolet band filter. Based on the infrared band filter, the visible light band filter, and the ultraviolet band filter, the infrared image frame, the visible light band image frame, and the ultraviolet band image frame are input to a full spectrum M-FSK decoder corresponding to each channel and then demodulated to generate a data stream, and the data stream of each channel can be decoded by a Walsh decoding method. The Walsh-decoded final data stream can be concatenated through a P/S (Parallel to serial) converter to complete the demodulation.

Referring to FIG. 14, a signal receiving method (S200b) of a signal receiving device (200b) according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description.

A full spectrum camera (hereinafter referred to as a 'rolling camera') including an infrared band filter, a visible light band filter, and an ultraviolet band filter based on a rolling shutter continuously captures multiple times the blinking of a full spectrum LED light source at different times, and stores each captured signal in one column or row of an image sensor to generate an image frame (S210b). The image frame may be an infrared band image frame, a visible light band image frame, and an ultraviolet band image frame in a strip shape as in FIG. 10.

The signal receiving device (200b) can generate an FSK modulation signal from a strip image frame such as Fig. 10 of an area where a full spectrum LED is photographed (S220b). The FSK modulation signal can be on or off values extracted from each row or column of an area where a full spectrum LED is photographed. For example, an FSK modulation signal (810) such as Fig. 9 can be generated from an image frame of an infrared band.

In one embodiment, the signal receiving device (200b) can determine the band of frequencies corresponding to the preamble by extracting the frequency after separating the signal corresponding to the preamble from the FSK modulation signal.

The signal receiving device (200b) extracts the frequency of the FSK modulation signal for each channel based on the number of pixels corresponding to the shutter speed and the on level (or off level) of the FSK modulation signal (S230b), and based on the bit-frequency mapping table as in <Table 1> and the extracted frequency, the signal receiving device (200b) can demodulate the FSK modulation signal of each band in the M-FSK manner to generate a data stream (S240b).

The signal receiving device (200b) can Walsh decode the M-FSK demodulated data stream to generate a final data stream (S250b).

Referring to FIG. 15, the configuration of a signal receiving device (200c) based on a full spectrum according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description. The signal receiving device (200c) according to the present embodiment can be used in correspondence to the signal transmitting device described above with reference to FIG. 2.

The signal receiving device (200c) may include a rolling camera (210c) which generates an image frame based on a signal acquired from an image sensor in a rolling shutter manner that receives a full-spectrum optical signal, a modulation signal generating unit (not shown) which determines an area in which a full-spectrum LED is photographed in the image frame and then extracts pulse level (ON/OFF) information based on a strip-shaped image of the area to generate an FSK modulation signal, a frequency extracting unit (220c) which Fourier transforms the FSK modulation signal and then extracts a frequency to divide the signal into an infrared band, a visible light band, and an ultraviolet band, a preamble detector (240b) which determines a frequency mapped to a bit code of each band based on the frequency of the preamble separated by the frequency extracting unit (220c) of the FSK modulation signal, and a full-spectrum M-FSK decoder which demodulates the FSK modulation signal in an M-FSK manner based on the frequency of the preamble and a bit-frequency mapping table or the frequency mapped to the bit code of each band determined by the preamble detector (240b) to generate a data stream.

The rolling camera (210c) of the signal receiving device (200c) can generate an image frame that includes information of all of the infrared band, the visible light band, and the ultraviolet band. Since the image frame includes information of all of the infrared band, the visible light band, and the ultraviolet band, the FSK modulation signal generated from the image frame includes both the optical information of each band of the optical modulation signal transmitted by the signal transmitting device and the frequency information of each channel.

Accordingly, the frequency extraction unit (220c) of the signal receiving device (200c) can extract multiple frequencies by Fourier transforming the FSK modulation signal including all frequency information of each channel into the frequency domain, and then extracting them as the frequencies of the preamble or payload of each channel. The extracted frequencies correspond to optical modulation signals of the infrared band, the visible light band, and the ultraviolet band, respectively.

In one embodiment, the frequency extraction unit (220c) of the signal receiving device (200c) can extract the frequency of each preamble of each channel, and then determine the frequency corresponding to the payload of each band based on the extracted frequency. That is, taking a channel corresponding to an infrared band as an example, the frequency for mapping to the bit code of the payload can be determined by evenly dividing the frequency of the lowest band and the frequency of the highest band among the two frequencies extracted from the preamble divided into channels corresponding to the infrared band at a preset interval.

Referring to FIG. 16, a signal receiving method (S200c) of a signal receiving device (200c) according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description.

A rolling shutter-based full-spectrum camera (hereinafter referred to as a “rolling camera”) continuously captures multiple shots of a full-spectrum LED light source blinking at different times, and stores each captured signal in one column or row of an image sensor to generate an image frame including information of an infrared band, a visible light band, and an ultraviolet band (S210c). Since the image frame is generated based on the rolling camera, it may be a strip-shaped image frame. Since the rolling camera is full-spectrum-based, it can sense information of an infrared band, a visible light band, and an ultraviolet band, and thus the widths of continuous strips may be different from each other.

The signal receiving device (200c) can generate an FSK modulation signal including information of an infrared band, a visible light band, and an ultraviolet band from a strip image frame of an area where a full spectrum LED is photographed (S220c). The FSK modulation signal can be on or off values extracted from each row or column of an area where a full spectrum LED is photographed.

In one embodiment, the signal receiving device (200c) can extract a frequency corresponding to a preamble by Fourier transforming an FSK modulation signal, and then determine a band of frequencies corresponding to a payload of each channel based on the frequency of the preamble.

The signal receiving device (200c) extracts a frequency corresponding to the payload of each band by performing a Fourier transform on a portion corresponding to the payload of the FSK modulation signal (the exact corresponding frequency of the payload portion can be determined by considering the frequency corresponding to the preamble) (S230c), and based on the bit-frequency mapping table as in <Table 1> and the extracted frequency, the signal receiving device (200c) can demodulate the FSK modulation signal of each band using the M-FSK method to generate a data stream (S240c).

Referring to FIG. 17, the configuration of a signal receiving device (200d) based on a full spectrum according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description. The signal receiving device (200d) according to the present embodiment can be used in correspondence to the signal transmitting device described above with reference to FIG. 2.

The signal receiving device (200d) may include a rolling camera (210c) which generates an image frame based on a signal acquired from an image sensor in a rolling shutter manner that receives a full-spectrum optical signal, a modulation signal generating unit (not shown) which determines an area in which a full-spectrum LED is photographed in the image frame and then extracts pulse level (ON/OFF) information based on a strip-shaped image of the area to generate a modulation signal, a filter unit (220d) which receives a modulation signal and inputs it to a plurality of frequency band filter circuits that pass signals of different frequency bands, thereby generating a plurality of FSK modulation signals, a preamble detector (240d) which determines a frequency of a preamble in the FSK modulation signal divided into each band, and a full-spectrum M-FSK decoder which receives a plurality of FSK modulation signals output from the plurality of band filter circuits of the filter unit (220d) as each channel, demodulates the FSK modulation signal in an M-FSK manner based on the frequency of the preamble and a bit-frequency mapping table in each channel, and generates a data stream.

The multiple band filter circuits of the filter section (220d) that receives the modulation signal can generate an FSK modulation signal of each band by applying a band filter corresponding to the frequency of the band related to each channel to the modulation signal including all frequencies of different bands, as shown in FIG. 18.

In the full spectrum M-FSK decoder, each FSK modulation signal with the preamble removed may have a different width (number of pixels) of a column (or row) corresponding to the ON of the full spectrum LED light source for each band. The signal receiving device (200d) may determine the frequency of the FSK modulation signal for each channel by considering the width corresponding to the ON level and the shutter speed of the rolling camera (210d). At this time, the frequency to be mapped to the bit code of the payload may be determined by further considering a position where the frequency of the lowest band and the frequency of the highest band among the two frequencies extracted from the preamble for each band are evenly divided at a preset interval.

The signal receiving device (200d) can demodulate the FSK modulation signal of each channel in the M-FSK manner based on the preset bit-frequency mapping table and the frequency extracted from it, and configure it as the payload of a packet to generate a data stream. The data stream can be the packet described above.

Referring to FIG. 19, a signal receiving method (S200d) of a signal receiving device (200d) according to another embodiment of the present disclosure is described. Parts that overlap with those described above are omitted for detailed description.

A full spectrum camera based on a rolling shutter (hereinafter referred to as a “rolling camera”) sequentially captures multiple shots of the blinking of a full spectrum LED light source at different times, and stores each captured signal in one column or row of an image sensor to generate an image frame including information of an infrared band, a visible light band, and an ultraviolet band (S210d). Since the image frame is generated based on a rolling camera, it may be a strip-shaped image frame.

The signal receiving device (200c) can generate a modulation signal including all information of light modulation signals of the infrared band, the visible light band, and the ultraviolet band from the strip image frame of the area where the full spectrum LED is photographed (S220d). The modulation signal can be on or off values extracted from each row or column of the area where the full spectrum LED is photographed.

In one embodiment, the signal receiving device (200d) can input a modulation signal to each of a plurality of band filter circuits that pass signals of different frequency bands to generate a plurality of FSK modulation signals (S220d). Thereafter, in one embodiment, the signal receiving device (200d) can extract a frequency of the preamble based on the width of the on level of a portion corresponding to the preamble in the plurality of FSK modulation signals and the shutter speed of the rolling camera (S230d). Similarly, the frequency of the payload can be extracted based on the width of the on level of a portion corresponding to the payload in the plurality of FSK modulation signals (S230d).

The signal receiving device (200d) can generate a data stream by demodulating the frequency of each extracted payload using the M-FSK method based on a bit-frequency mapping table such as the preset <Table 1>, or by demodulating the frequency of each payload using the M-FSK method based on frequencies corresponding to the payload of each band determined based on the frequency of the preamble (S240d).

The above-described present disclosure can be implemented as a computer-readable code on a medium in which a program is recorded. The computer-readable medium includes all kinds of recording devices that store data that can be read by a computer system. Examples of the computer-readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like. In addition, the computer may include a processor of each device.

Meanwhile, the above program may be specially designed and configured for the present disclosure or may be known and available to those skilled in the art of computer software. Examples of the program may include not only machine language codes produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

The use of the term "above" and similar referential terms in the specification of this disclosure (especially in the claims) may refer to both the singular and the plural. In addition, when a range is described in this disclosure, it is intended that the invention be applied to individual values falling within the range (unless otherwise stated), and it is the same as describing each individual value constituting the range in the detailed description of the invention.

Unless the steps constituting the method according to the present disclosure are explicitly described in an order or contrary description, the steps can be performed in any suitable order. The present disclosure is not necessarily limited by the order in which the steps are described. The use of all examples or exemplary terms (e.g., etc.) in this disclosure is merely intended to describe the present disclosure in more detail and is not intended to limit the scope of the present disclosure due to the examples or exemplary terms, unless otherwise defined by the claims. In addition, those skilled in the art will appreciate that various modifications, combinations, and changes can be configured according to design conditions and factors within the scope of the appended claims or their equivalents.

Therefore, the idea of the present disclosure should not be limited to the embodiments described above, and not only the scope of the patent claims described below, but also all scopes equivalent to or equivalently modified from the scope of the patent claims are considered to belong to the scope of the idea of the present disclosure.

100, 100b, 100c, 100d: Signal Transmitter
200,200b,200c,300d: Signal receiving device

Claims (8)

An optical signal receiving method in which a processor of an optical signal receiving device including a rolling shutter-based camera capable of capturing a full spectrum band performs each step,
A step of generating an image frame including all light information of an infrared band, a visible light band and an ultraviolet band based on a sensor signal of the camera that photographs a light source including a full-spectrum LED;
A step of extracting level change information from an area where the light source is photographed in the image frame and generating an FSK modulation signal;
A step of extracting the frequency after Fourier transforming the above FSK modulation signal and dividing it into multiple bands; and
A step of demodulating the FSK modulation signal divided into multiple bands using the M-FSK (Mary-Frequency Shift Keying) method based on a preset bit-frequency mapping table and the frequency to generate a data stream for each band, and merging the data streams for each band,
The step of dividing into the above multiple bands is:
Based on the above FSK modulation signal and the bit-frequency mapping table, the synthesized frequency related to each band's fundamental frequency is multiplied, and then the FSK modulation signal multiplied by the band's synthesized frequency is Fourier transformed to extract the frequency.
Method for receiving full spectrum optical signals.
In the first paragraph,
The steps for generating the above data stream are:
Further comprising a step of demodulating the frequency of the lowest band and the frequency of the highest band among the frequencies divided into each band into a bit code of the preamble of the data stream.
Method for receiving full spectrum optical signals.
In the second paragraph,
The steps for generating the above data stream are:
A method of demodulating frequencies located at equal intervals between frequency bands corresponding to the preamble into bit codes of the payload of the data stream, wherein the frequencies mapped to the payload are frequencies having a difference of 10 times or more for each channel.
Method for receiving full spectrum optical signals.
In the first paragraph,
The above image frames are each demodulated into different bit codes of the payload of the data stream for each band.
Method for receiving full spectrum optical signals.
A full spectrum camera that generates images by receiving full spectrum light signals transmitted from full spectrum LEDs;
at least one processor; and
A memory electrically connected to the processor and storing at least one code to be executed by the processor,
The above memory, when executed through the processor, causes the processor to:
Based on the sensor signal of the camera that captures the light source including the full spectrum LED, an image frame containing all the light information of the infrared band, the visible light band and the ultraviolet band is generated,
Extracting level change information from the area where the light source is photographed in the image frame to generate an FSK modulation signal,
After Fourier transforming the above FSK modulation signal, the frequency is extracted and divided into multiple bands.
A code is stored that causes the FSK modulation signal divided into multiple bands to be demodulated using the M-FSK (Mary-Frequency Shift Keying) method based on a preset bit-frequency mapping table and the frequency to generate a data stream for each band, and to merge the data streams for each band.
The above memory causes the processor to:
A code is further stored that causes the FSK modulation signal and the bit-frequency mapping table to be multiplied by a synthesized frequency related to each band's fundamental frequency, and then the FSK modulation signal multiplied by the synthesized frequency for each band is Fourier transformed and then the frequency is extracted.
Full spectrum optical signal receiving device.
In clause 5,
The above memory causes the processor to:
Further storing a code that causes the lowest frequency and the highest frequency of each band among the frequencies divided into each band to be demodulated into the bit code of the preamble of the data stream.
Full spectrum optical signal receiving device.
In Article 6,
The above memory causes the processor to:
Further storing a code that causes frequencies located at equal intervals between the frequency bands corresponding to the above preamble to be demodulated into bit codes of the payload of the above data stream,
The frequencies mapped to the above payload are frequencies that have a difference of more than 10 times for each channel.
Full spectrum optical signal receiving device.
In clause 5,
The above image frames are each demodulated into different bit codes of the payload of the data stream for each band.
Full spectrum optical signal receiving device.

Images