CN207835456U - A kind of visible light communication system based on flat lamp and mobile terminal camera - Google Patents
A kind of visible light communication system based on flat lamp and mobile terminal camera Download PDFInfo
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- CN207835456U CN207835456U CN201820031981.XU CN201820031981U CN207835456U CN 207835456 U CN207835456 U CN 207835456U CN 201820031981 U CN201820031981 U CN 201820031981U CN 207835456 U CN207835456 U CN 207835456U
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- visible light
- mobile terminal
- flat lamp
- communication system
- led
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Abstract
The utility model discloses a kind of visible light communication system based on flat lamp and mobile terminal camera, system includes transmitter and receiver, and it is the mobile terminal with CMOS camera that transmitter, which includes the LED flat lamp of embedded system and its peripheral circuit driving, receiver,;The light that LED flat lamp can send out LED point light source is converted into area source, is conducive to the reception and imaging of CMOS camera.Technology used by the utility model is based on visible light communication technology, have many advantages, such as pairing rapidly, safety is good, is not easy to be tampered, is of low cost, be the ideal short-range communication technique of mobile payment, have a vast market application prospect.
Description
Technical field
The utility model is related to technical field of visible light communication, more particularly to a kind of to be imaged based on flat lamp and mobile terminal
The visible light communication system of head.
Background technology
In recent years, with the rapid development of LED illumination industry, LED is widely used in all trades and professions.With it is traditional
Lighting source such as incandescent lamp is compared with energy-saving lamp, and not only small power consumption, brightness are high by LED, also possess good modulating performance.By human eye
The high-frequency signal of None- identified is loaded on LED, has expedited the emergence of out a new technology --- visible light communication technology.
On the other hand, with the maturation of the technologies such as universal and Quick Response Code/bar code of smart mobile phone, mobile payment is due to it
Convenient and efficient and the favor for increasingly receiving people.Although the technologies application cost such as Quick Response Code/bar code is low, convenient and efficient,
Its safety is not high, can be decoded it by disclosed decoding standard, thus requires high occasion to be faced with safe and secret
Information leakage and the risk being tampered.And smart mobile phone on the market nearly all carries CMOS camera, exposure side at present
The roller shutter effect that formula is brought can be applied in visible light communication technology, replace photodiode connecing as visible light signal
Device is received, to substantially increase the universal cost and use value of visible light communication technology.
Current visible light communication technology is frequently with LED lamp bead as signal emitting-source, and LED lamp bead shines and excessively collects
In, the phenomenon that will produce local overexposure in CMOS camera, to bring larger difficulty to decoding.
Utility model content
The shortcomings that the purpose of the utility model is to overcome the prior arts and deficiency provide a kind of based on flat lamp and movement
The visible light communication system of terminal camera, the utility model are based on visible light communication technology, have and match rapid, safety
Good, the advantages that being not easy to be tampered, is of low cost, have a vast market application prospect.The visible light of low error rate may be implemented
Communication, is the ideal short-range communication technique of mobile payment.
The purpose of this utility model is realized by the following technical solution:One kind being based on flat lamp and mobile terminal camera
Visible light communication system, including:Transmitter and receiver;Transmitter includes regulated power supply, booster circuit, reduction voltage circuit, embedding
Embedded system, LED drive circuit and LED flat lamp;Receiver is the mobile terminal with CMOS camera;It transmitter and connects
Receipts machine cascades successively, constitutes complete VLC systems.
Preferably, regulated power supply powers to LED drive circuit by booster circuit, while by reduction voltage circuit to embedded
System power supply;Embedded system is modulated transmission data, and analog voltage letter is exported to LED drive circuit by GPIO interface
Number, analog voltage signal can be converted into the current signal that suitable LED drives, electricity by the DD311 chips on LED drive circuit
It flows signal driving LED flat lamp and sends visible light signal.
Preferably, the LED flat lamp uses side entering type flat lamp, and light output light intensity distributions are uniformly and without bright spot
Or dim spot.
Preferably, the mobile terminal for carrying CMOS camera receives visible light letter by its internal cmos image sensor
Number and be translated into electric signal, so as to be demodulated to obtain original data to signal inside mobile terminal.
Preferably, the coding of above-mentioned visible light communication system modulates+39 yards of coding method using OOK, it would be desirable to send
Data become striped by 39 yards of coding mode coding, so that modulated striped be emitted using transmitter.
The utility model compared with prior art, has the following advantages that and advantageous effect:
(1) the utility model is exposed using the jelly effect and row pixel of the smart mobile phone camera CMOS Rolling shutters carried
Eclipsing effects will be seen that the striped picture that optical signal is converted between a bright dark phase of frame frame between light time, to be demodulated to coding.
And cmos image sensor is widely used in current mobile phone camera on the market already, then be aided with corresponding mobile terminal and answer
With software, this is very beneficial for the practical application of the utility model.
(2) the utility model using side entering type flat lamp as visible light signal emission source, avoid local overexposure to
The problem brought is decoded, and is more uniformly distributed compared with common LED lamp intensity of illumination distribution, equally dazzling without the latter, practicability is more
By force.
Description of the drawings
Fig. 1 is the connection figure of embodiment transmitter each section.
Fig. 2 is coding and signal transmission flow figure of the embodiment based on STM32.
Fig. 3 is embodiment decoding process figure.
Fig. 4 is embodiment visible light communication system complete machine concept map.
Fig. 5 is embodiment waveform reduction process schematic diagram.
Specific implementation mode
The present invention will be further described in detail with reference to the embodiments and the accompanying drawings, but the implementation of the utility model
Mode is without being limited thereto.
Embodiment 1
A kind of visible light communication system based on mobile phone camera and flat lamp, including transmitter and receiver.Described
Transmitter includes regulated power supply, booster circuit, reduction voltage circuit, embedded system, LED drive circuit and LED flat lamp;It is described
Receiver be the mobile terminal with CMOS camera, including cmos image sensor.The transmitter and receiver according to
Secondary cascade constitutes complete VLC (Visible Light Communication) system.The embedded system is flat to LED
Plate lamp sends the letter modulated by 39 yards (39 yards are a kind of bar codes recording binary data using striped width) and OOK
Number, the LED flat lamp sends visible light signal to the mobile phone camera with cmos image sensor, and the cmos image passes
Sensor will be seen that optical signal is converted into bar code using its Rolling shutter, by decoding the data that can be transmitted.
Regulated power supply powers to LED drive circuit by booster circuit, while being supplied to embedded system by reduction voltage circuit
Electricity.Embedded system is modulated transmission data, and analog voltage signal, mould are exported to LED drive circuit by GPIO interface
Quasi- voltage signal can be converted into the current signal of suitable LED drivings, electric current letter by the DD311 chips on LED drive circuit
Number driving LED flat lamp send visible light signal.
LED flat lamp uses side entering type flat lamp, special construction to make light output light intensity distributions uniformly and without bright
Point or dim spot.
Mobile terminal with CMOS camera receives visible light signal by its internal cmos image sensor and will
It is converted into electric signal, so as to be demodulated to obtain original data to signal inside mobile terminal.The CMOS
Imaging sensor, will be on the image when the variation of visible light signal is very fast since its data reading mode is to read line by line
The striped between bright dark phase is generated, using 39 yards of decoding process of ON-OFF keying modulation, the data of transmission can be restored.
As shown in Figure 1.First, 39 yards and OOK modulation are carried out to signal using STM32.Since DD311 drives with constant current
Function, and the required voltage under rated current of LED lamp used by the present embodiment is 13.5V, therefore input the voltage of DD311
Can take more than 13.5V, the arbitrary value being less than between DD311 pressure voltages 36V is chosen for 15V in the present embodiment, the voltage by
Booster circuit provides.The operating voltage that STM32 systems need is 3.3V, which is provided by reduction voltage circuit.In view of boosting
Voltage reduction module grade, is associated in the output end of boost module by the particular/special requirement of sample circuit in module herein, and avoiding interfering with each other makes
Circuit function is abnormal.The 3.3V voltages of reduction voltage circuit output are by being linked into the references of DD311 circuits after a 2.2k Ω resistance
Current input terminal provides the reference current that size is 1.5mA.The voltage modulated that STM32 system output voltage amplitudes are 3.3V is believed
Number, become the current drive signal that current maxima is 150mA after the amplification of DD311 chips and is linked into LED flat lamp.Electric current
Drive signal drives LED flat lamp to send visible light signal, it is seen that after optical signal transmission reaches receiving terminal, by mobile phone camera
Cmos image sensor receives and is converted into image output.The time for exposure of camera is set as 1/20000s, ISO 800.
A kind of coding and decoding method realized based on above system.
The launching procedure flow graph being illustrated in figure 2 in STM32.In the present embodiment, with word ' S ' (corresponding binary number
According to for { 001000110 }) for illustrate to code and decode flow.
1, first, STM32 is first initialized, and opens timer and the GPIO used mouths are set 1.
2, the striped of first character to be exported of Programmable detection, first striped of character ' S ' is narrow strips, then by GPIO
Be delayed 1 chronomere after negating.
3, after having detected first striped, second striped is obtained, corresponding 39 yards of seconds of character ' S ' are narrow strips,
Be delayed 1 chronomere after then GPIO is negated.Detection third striped corresponds to be delayed 3 after wide striped then negates GPIO
Chronomere repeats this step when detecting intercharacter space, and be delayed 2 chronomeres after GPIO is negated, and completes word
Accord with coding and the output of ' S '.
4, above-mentioned two step is repeated, the character in a cycle is sent, is finished until entire character string exports, after GPIO is negated
Be delayed 4 chronomeres.
If camera acquisition is picture, the same character string of output is recycled;If camera acquisition is video, with
1/30 second is character string of a cycle involuntary conversion, and the same character string is still exported in the period.
It is illustrated in figure 3 the decoding process figure of mobile phone terminal.
1, first, the processor of mobile phone obtains the frame image that camera takes, and intercepts the sample of vertical strip simultaneously
By its gray processing, noise reduction process is carried out, then is translated into the one-dimensional square of gray scale by Wiener filtering, one-dimensional mean filter
Battle array.
2, as shown in figure 5, obtained waveform is corrected, make its maximum value close to 255, minimum value is close to 0.By institute
The dark corner effect of the camera for the mobile terminal with cmos image sensor stated, the obtained brightness of image of shooting is from center
Successively decrease around and successively decrease and meets quadratic law, thus it is bright dark as striped to need to fit the quadratic function curve
Criterion.When waveform is more than curve, be determined as it is bright, be otherwise determined as it is dark, to restore bar code.Fitting is obtained again
Quadratic function curve be used to judge the bright dark of striped, it is (in Fig. 5 corresponding to restore the corresponding 39 code-bar line of character ' S '
The a bit of striped in front).
3, into after restoring bar code, the width of each striped is measured from left to right, by each striped of the journal of striped
Width, obtain width of fringe data.It can be seen that the width of striped can be divided into 4 kinds.Maximum width is outlier, is represented
The clear area at character starting/end followed by represents the point of wide striped, and width minimum is the point for representing narrow strips, and width is situated between
What the point between wide striped and narrow strips represented is the interval between character.A cycle when between each two outlier.
After detecting first outlier, from left to right read 9 points width data, read result be 6,6,15,
7,5,6,16,16,6}.This 9 data are arranged from big to small by width value again, result be 16,16,14,7,6,6,6,
6,5}.3 labels of maximum are that remaining 6 labels are, to convert width of fringe data to binary data:
{ 001000110 }, it is ' S ' that the coding mode further according to 39 yards, which can acquire the character representated by 9 bit binary data,.
Above-described embodiment is the preferable embodiment of the utility model, but the embodiment of the utility model is not by above-mentioned
The limitation of embodiment, under other any Spirit Essences and principle without departing from the utility model made by change, modify, replace
In generation, simplifies combination, should be equivalent substitute mode, is included within the scope of protection of the utility model.
Claims (5)
1. a kind of visible light communication system based on flat lamp and mobile terminal camera, which is characterized in that including:Transmitter and
Receiver;Transmitter includes regulated power supply, booster circuit, reduction voltage circuit, embedded system, LED drive circuit and LED flat plate
Lamp;Receiver is the mobile terminal with CMOS camera;Transmitter and receiver cascades successively, constitutes complete VLC systems.
2. the visible light communication system according to claim 1 based on flat lamp and mobile terminal camera, feature exist
In regulated power supply powers to LED drive circuit by booster circuit, while being powered to embedded system by reduction voltage circuit;It is embedding
Embedded system is modulated transmission data, and analog voltage signal, analog voltage are exported to LED drive circuit by GPIO interface
Signal can be converted into the current signal of suitable LED drivings, current signal driving by the DD311 chips on LED drive circuit
LED flat lamp sends visible light signal.
3. the visible light communication system according to claim 1 based on flat lamp and mobile terminal camera, feature exist
In the LED flat lamp uses side entering type flat lamp.
4. the visible light communication system according to claim 1 based on flat lamp and mobile terminal camera, feature exist
In the mobile terminal with CMOS camera receives visible light signal by its internal cmos image sensor and converted
For electric signal, so as to be demodulated to obtain original data to signal inside mobile terminal.
5. the visible light communication system according to claim 1 based on flat lamp and mobile terminal camera, feature exist
In, it is seen that the coding of optical communication system modulates+39 yards of coding method using OOK, it would be desirable to which the data of transmission press 39 yards of volume
Code mode encodes as striped, to be emitted modulated striped using transmitter.
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CN201820031981.XU CN207835456U (en) | 2018-01-09 | 2018-01-09 | A kind of visible light communication system based on flat lamp and mobile terminal camera |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108023640A (en) * | 2018-01-09 | 2018-05-11 | 华南理工大学 | A kind of visible light communication system based on flat lamp and mobile terminal camera |
CN111445608A (en) * | 2020-04-30 | 2020-07-24 | 华南理工大学 | Novel access control system based on optical strip barcode generation and identification technology |
-
2018
- 2018-01-09 CN CN201820031981.XU patent/CN207835456U/en not_active Expired - Fee Related
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108023640A (en) * | 2018-01-09 | 2018-05-11 | 华南理工大学 | A kind of visible light communication system based on flat lamp and mobile terminal camera |
CN108023640B (en) * | 2018-01-09 | 2024-02-13 | 华南理工大学 | Visible light communication system based on flat lamp and mobile terminal camera |
CN111445608A (en) * | 2020-04-30 | 2020-07-24 | 华南理工大学 | Novel access control system based on optical strip barcode generation and identification technology |
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Granted publication date: 20180907 Termination date: 20210109 |