CN101159821B - Device for realizing acceptanceand output of optical communication signal by light receiver area array sensor - Google Patents
Device for realizing acceptanceand output of optical communication signal by light receiver area array sensor Download PDFInfo
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Abstract
The invention provides a signal output method of an optical receiver area array sensor, wherein the receiver firstly identifies and responds pixel positions of useful optical signals according to space and time characters of a light source, then selectively outputs the pixel signals and removes the pixel output only responding environment light. Meanwhile, the invention introduces a synchronous sampling technology for synchronizing the output sampling of the area array sensor and the frequency of light pulse and ensuring the integrity of signals during high speed communication.
Description
Technical field
The invention belongs to the light wireless communication field, particularly a kind of a kind of signal output method with optical receiver of imaging optical system and face array photoelectric sensor.
Background technology
Optical communication system is seen from channel angle can be divided into wire communication and radio communication two classes.The present major technique of light wire communication is optical fiber communication, has become the key technology in the transmission network.Light wireless communication system mainly contains two kinds of laser communication and infrared communications at present on used radiative characteristic.Laser communication generally is used for longer-distance point-to-point communication, and one of major technique of infrared communication is IrDA (The Infrared Data Association) standard that is used for portable equipment low coverage exchanges data.
General optical communication system receiver mainly is made up of optical system, photodetector and signal processing circuit.Optical system is collected, the light signal of filter space, and it is focused on the photodetector; Photodetector is converted to the signal of telecommunication with light signal and outputs to signal processing circuit; Final dateouts such as signal processing circuit is amplified accordingly, filtering, detection, demodulation, decoding.Corresponding photodetector of transmitting illuminant normally in such optical communication system is even the optical fiber telecommunications system of multiplexing multiple signals finally behind the receiving terminal demultiplexing, also is detectors one road light signal on the space.The direct detecting pattern of the general employing of the optoelectronic receiver that signal post uses is not promptly considered the phase information of light signal, and only considers the energy information of light signal that the output of detector is continuous analog electrical signal, and the form of signal depends on radiative modulation format.If pulsed light, then output also is the signal of telecommunication of pulse.
Visible light communication is continue laser, a kind of emerging communication technology after infrared.Along with the fast development of illumination LED industry, utilize illumination LED to realize that visible light communication will become a kind of of current communications systems and replenish or substitute, particularly on indoor short distance high-speed radiocommunication is used.The realization principle of visible light communication system and basic comprising and laser, infrared communication system are similar.Be applied to normally portable equipment of indoor Wireless Telecom Equipment, as notebook computer, mobile phone, audio/video player, digital camera, game machine etc.And be to utilize the photo electric imaging system that himself carries to realize reception to the visible light communication signal with a kind of short-cut method that these equipment are linked into communication network by optical communication, as the camera on notebook computer and the mobile phone.One of most probable application scenarios is to utilize led array to send multipath light signal, forms the picture of these LED by the imaging optical system of each portable equipment on its imageing sensor, and different detection pixel correspondences different LED.Can independent detection if these survey pixels, the corresponding LED light signal of output, so just can realize multichannel or multiple access optical communication.
The photodetector of unit is realized continuous opto-electronic conversion, and corresponding output is continuous analog signal, and treatment circuit thereafter normally amplifies, filtering etc.The detector of face battle array if not being on a grand scale, such as having only 32 * 32 pixels, can independently be treated the output of each pixel so, and each surveys pixel and subsequent conditioning circuit constitutes independently output channel.To 32 * 32 planar array detectors 1024 independently parallel continuous output channels should be arranged.This implements concerning the modern integrated circuits technology is not to be very difficult.
But existing imageing sensor (comprising area array sensor in the future), no matter be CCD's or CMOS, as the ICX418AKL (colour TV camera 8mm ccd image sensor) of SONY and KAI-0330 (648 * 484 ccd image sensor), the KAC-9628 (648 * 488 cmos image sensor) of KODAK, all be the integrated of face battle array photodetector and output sampling/treatment circuit, its output is the sampling value in a certain moment of detector, rather than output continuously.
The way of output that the normal CCD imageing sensor adopts is to transfer to and be listed as on vertical CCD linear array that the pixel spacing is provided with in the response signal that synchronization is surveyed all picture dots to store, and then the signal on each vertical CCD transferred on the horizontal CCD linear array one by one, be equivalent to delegation's signal, laterally CCD serial output one by one under clock drives again at every turn.The way of output and the ccd image sensor of cmos image sensor are similar, and the output that is the CMOS column signal is not to be the value of synchronization, export but export the back of lining by line scan or scan the back by unit.
The sampling output of CCD and cmos image sensor is the analog signal that disperses, but not continuous analog signal.Discrete analog signal becomes digital signal again after the correlated-double-sampling that carries out subsequently (CDS) analog to digital conversion.The mode why the employing sampling is exported is because the scale of face battle array pixel quantity is too big on the one hand, is difficult to planning millions of even up to ten million parallel processing and output channel in integrated circuit; Another aspect does not need too high output frequency as image or Video Applications, stores the output of serial again or scan output can satisfy instructions for use.
Yet, if use the sensitive detection parts of similar imageing sensor as the multichannel optical receiver, the parameters such as the detectivity that relates to except conventional photodetection, response time, response band, will have two problems so: one is the selection problem of output picture dot; One is output sampling and the stationary problem that receives light.
When using imageing sensor to survey communicate optical signal, the pixel that the pixel of response is not all, and may only be the part picture dot, this is relevant with the relative position that sends light source and optical receiver.So how to shield the response signal of other irrelevant picture dots, and only export effective signal of communication,, reduce redundant signals and have a significant impact improving message transmission rate to surround lighting.When particularly still adopting the mode of sampling output,, so under same output clock drives, will be increased sharply at the output speed of part picture dot if can select to the output picture dot.
The light signal that light wireless communication system sends is a modulation signal, adopts pulse amplitude modulation (PAM) usually, pulse frequency modulated (PFM), pulse width modulation (PWM) or pulse position modulation (PPM) etc.Which kind of modulation system no matter, its performance all is the light signal of discontinuity.If modulation signal can be exported continuously, then can the contained information integrity of inhibit signal.If but detector adopts sampling output, theoretically,, just might keep information integrity more than the sampling frequency of output being brought up to the twice of light pulse signal bandwidth only according to nyquist sampling theorem.If the communication data rate of expectation is very high, corresponding optical pulse frequency is just very high, and this sampling rate is difficult to satisfy.
The output that the present invention is directed to face array photoelectric sensor all shows as the characteristics of discreteness on room and time, for improving traffic rate, in the optical receiver that uses face array photoelectric sensor, introduced a kind of picture dot of exporting and selected and exported the method for taking a sample with the irradiates light impulsive synchronization.
Summary of the invention
Receiver in to the effect that a kind of light wireless communication system of the present invention, its principal character is that optical receiver adopts face array photoelectric sensor, can select specific picture dot signal output in the area array sensor, the sampling of output is constantly synchronous in time with the illumination pulse.
The present invention is based on a light transmitting element and a light receiving unit.Basic composition comprises that light sends point source or light sends array, at receiving terminal an imaging optical system is arranged, face battle array photodetector with and output and treatment circuit.Obviously, such light receiving unit can with image/video acquisition system dual-purpose.
The light transmitting element sends the pulsed optical signals of modulating according to the agreement of communication system, and these signals are being represented the data that send.Imaging on face battle array photodetector after light signal process space channel and the optical system, planar array detector is exported photoelectric conversion signal under the control of output circuit, send treatment circuit that signal is carried out demodulation, decoding etc. then and handle the final data that receive of back output.
In practical communication was used, planar array detector also to the surround lighting response, and may take more pixel except the useful signal response that transmitting terminal is sent light source.If all the response signal of picture dot is all given output, will in subsequent conditioning circuit, produce many unnecessary signals so, make useful signal extract the difficulty that becomes, transmission rate also can't improve effectively.At this problem, the present invention introduces useful picture dot output option program in receiving course: adopt two kinds of methods to confirm useful picture dot, select output then, reduce or eliminate the response output of non-Communication ray signal.
A kind of is image process method, according to the physical features that sends light source.At first when initial imaging,,,, use the method for pattern recognition that its position in area array sensor is determined as target to be detected in the entire image such as light-emitting diode (LED) with light source.No matter LED is bright or dark, present image-capable is all realized easily.This method is the equal of to handle in the space.
The 2nd, adopt the aid identification method.Make the LED of transmitting terminal cooperate the identification of receiving element to send the signal of certain pulses frequency and brightness, receiving terminal is gathered multiple image.Suppose not changing at short notice of surround lighting, perhaps the mode of Bian Huaing is different from the optical pulse frequency of LED, by the multiple image of gathering is compared, carries out related operation so, just can find to meet the response point of specific led light source, locate its position on area array sensor thus.This method is the equal of the room and time Combined Treatment.
Above-mentioned two kinds of methods can be used separately, also can use together; Can after the initiation communication request, use, also can in communication process, dynamically re-use for further revising.
When behind the position of having determined useful picture dot sometime, change sequential, the frequency of output drive signal, perhaps rank addresses is selected signal, makes the output of the useful picture dot of its selection, and does not consider the response of other picture dots, just can improve the efficient of transmission channel.
In common optical communication system, the light signal of transmission is pulse, posts no matter the position of carrying data message is pulse spacing, pulse amplitude or pulse duration, all requires the output of photoelectric sensor can not lose these information.But general area array sensor and discontinuous output but sampling output, the frequency of sampling and constantly be image/video collection for low rate, therefore with Communication ray pulse at a high speed without any matching relationship, directly apply mechanically and can lose a lot of pulse informations.The present invention introduces the measure of synchronized sampling for addressing this problem in optical receiver, guarantee that promptly the output in the sampling moment can be write down the information of irradiates light pulse fully.Regardless of pulse modulated mode, sample circuit guarantees that starting photoelectric conversion unit in initial moment of pulse period enters the electric charge cumulative process, is the quantity of electric charge with the power conversion of light signal, and in the finish time pulse period quantity of electric charge is exported.So circulation, the information of each light pulse can be gathered fully, and can not obscure with adjacent optical pulse information.
When the photoelectric sensor that does not have continuously output is auxiliary, synchronization point catch the mode that can adopt search.One of method is that light source at first sends pulse period, the fixing preamble pulse string of pulse duration, and output sampling circuit is taken a sample to transducer with the same cycle and exported.Synchronization point is relevant with phase place, at first sends the sample trigger pulse with arbitrary phase, then according to variation big or small between continuous two output valves, the phase place of adjusting the subsequent triggers pulse changes to the output augment direction, at lasting a plurality of all after dates, can capture maximum output valve, and continue to follow the tracks of.
Solved output and selected and stationary problem, just imageing sensor can be used for the high-speed, multi-path optical receiver, high-frequency light pulse signal just can be exported in real time and not be subjected to the interference of other pixel signal.
Description of drawings
Fig. 1 is a composition diagram of the present invention.Led light source of transmitting terminal (also can be led array) is by photographic optical system imaging on imageing sensor, and the picture dot that is covered is converted to the selected output of the signal of telecommunication to the response of LED light signal.
Fig. 2 adopts the conventional camera system of cmos image sensor to constitute.
When Fig. 3 shows that the sampling period is less than pulse signal cycle, always can collect two kinds of different conditions of signal.
Fig. 4 is a dual output pattern shift register of the present invention, and output is discrete analog signal, can also can select the signal output of arbitrary picture dot as conventional serial outputting video signal.
Fig. 5 is the identification process of communication light source image space on imageing sensor of adopting of the present invention.
Fig. 6 is the modulating light pulse sequence of transmitting terminal and the sample trigger moment and the phase relation of output signal synchronously time of receiving terminal imageing sensor.
Fig. 7 is that the synchronization acquistion tracking circuit of imageing sensor output is formed.
Fig. 8 is the input-output characteristic of the amplitude comparator of imageing sensor output synchronous circuit.
Fig. 9 is the synchronization acquistion tracing process signal of the triggering signal of receiving terminal imageing sensor sampling output.
Embodiment
Based on the optical receiver of face array photoelectric sensor, can carry out space division multiplexing communication by imaging system in theory.But, be example with single transmission light source in order to simplify explanation of the present invention.Fig. 1 is the optical communication system of a simplification.At the light transmitting terminal, the data flow of transmission is modulated into pulse signal through modulator (1-1) and sends by LED (1-2).At optical receiving end, by imaging optical system (1-3), the light source of transmitting terminal images in imageing sensor (1-4) and goes up formation hot spot (1-5).Imageing sensor (1-4) is made up of numerous pixels, and each lattice is represented a pixel among the figure, but 16 * 16 lattices that 1-4 shows among Fig. 1 are not the actual size with regard to the presentation video transducer, and is often much bigger possibly.Generally, this light wireless communication system is used for indoor short-range communication more, therefore the concentrated light area (1-5) of LED (1-2) on imageing sensor (1-4) tends to cover a plurality of pixels, even up to a hundred pixels, and the situation among Fig. 1 only has the dozens of pixel to represent.This extra-regional other pixel receives illumination equally, only is useful Communication ray, but surround lighting.
Row address decoder among Fig. 1 (1-6) is exported the row coded address under the control of dsp controller (1-9), the picture dot of gating delegation outputs to shift register (1-7).Under image pickup mode, delegation's signal that shift register (1-7) is preserved is outputed to DSP signal processor (1-9) by serial and handles, and obtains final image or vision signal.Here the DSP integrating representation the relevant processing capacity of vision signal of discrete output, comprise video amplification, analog-to-digital conversion, OK/frame synchronization, image processing etc.Under communication pattern, row address decoder (1-6) will be transferred to delegation's signal of a bit register (1-7) under the control of DSP (1-9) specific one or several directly transfer among the DSP by variable connector (1-8).Utilize any one or the several picture dot output that can select in the imageing sensor address decoder and cooperating of MUX like this.
Conventional imageing sensor output is in order to take a picture or to make a video recording, and therefore is the output of a view picture one view picture ground.If normal video, the output speed of per second tens frames so at most is though total data rate than higher, can reach several megahertzes, but to each pixel, still has only the sampling output speed of per second tens times.This is too low to communicating by letter.
If the situation of Fig. 1 is in communications status, and still according to the way of output of conventional video, response signal serial output with whole pixels, and then in the signal of output, select useful signal of communication, to face two problems so: one is to be subjected to the restriction of output channel bandwidth can't improve the speed of response of single pixel at all, another one is that a large amount of output signals all is the bias light signal, and these signals are useless.These of two problems have limited the data rate that light sends, and cause difficulty for the extraction of useful signal for one.If each pixel is not and line output, even total the data output rate of taking measures to improve is still less feasible so in practice.
The way of output of conventional imageing sensor as shown in Figure 2, this is a kind of typical way of output of cmos image sensor.The driving that cmos image sensor (2-1) is subjected to row address decoder (2-2) line by line or interlacing the signal of photoelectric sensor response is transferred on the horizontal shift register (2-3), different with delegation's continuous analog signal of exporting during the simulated television line scanning, the signal here is the analog signal that disperses.Shift register then under the driving of master clock by turn output signal carry out suitable amplification with the coupling analog to digital converter to the video amplifier (2-5), analog to digital converter (2-6) is delivered to digital signal processing unit (2-4) with discrete analog signal conversion for the pure digi-tal signal and is carried out corresponding image processing and storage.The output speed of transverse shift register has determined the output speed of whole picture dots.Under this type of drive, the output speed of any pixel equates with frame rate, view image-position sensor and video standard different, greatly about tens to up to a hundred per seconds.Frame rate as the KAC-9628 of KODAK is 30fps, and its number of picture elements is 648 (H) * 488 (V).
The scheme that the present invention uses no longer adopts the conventional way of output, but exports the response signal of picture dot selectively.At Fig. 1 situation is exactly the picture dot signal output of only selecting under hot spot (1-5) covering, like this can be in total output signal basic assurance is not subjected to the obstruction and the upset of ambient light signal, thereby total data output bandwidth can be exclusively enjoyed by useful signal and improved data rate greatly.
If select the output of useful pixel, at first must define with the position of picture dot in imageing sensor, can show in the mode of X, Y coordinate and can deliver to row, column address decoder decoding selection.
For imageing sensor, image output is basic function, and adopting image process method that specific light emitting source is positioned is the technology of comparative maturity.Suppose and use the light source of visible light LED as transmitting terminal, a kind of fairly simple location way is that transceiver cooperates, make the LED of transmitting terminal bright entirely, the image of receiving terminal imageing sensor output this moment will have a very significantly hot spot in background, the shape of this hot spot promptly is the shape of LED when luminous.Adopt the general algorithm of image recognition promptly it can be identified.For can be more effective, quick identification light source imaging drop point more, the cooperation of light source will be very effective.One of method that cooperates is the recurrent pulse that sends shown in 3-1 among Fig. 3, pulse duty factor 50%, and the frame period that the cycle can export greater than imageing sensor is shown in 3-2 among Fig. 3.The image that can make output that is provided with like this collects light source different situation when bright and dark respectively, and the related information of more identifications is provided.
The flow process of identification as shown in Figure 5.At first obtain relevant light source characteristic information as much as possible, continuous acquisition multiple image I then at receiver end
n(u, v), n=1,2,3 ...If do not consider the wavelength of light source, so image is carried out the two-value processing and become the amount of calculation that black and white image can reduce image processing greatly.When two-value is handled threshold value T choose the brightness and the contrast of communication light source brightness that can consider surround lighting, can further on image, give prominence to communication light source LED like this, and limit other background object.When higher, can select bigger T such as the brightness ratio of LED.In the image behind the thresholding, the surround lighting that filters out is just many like this.A few width of cloth consecutive image U after thresholding is handled
n(u, v), n=1,2,3 ..., make the absolute value additive operation with adjacent separately image respectively, produce new image F
n(u, v), n=1,2,3 ...Under the situation that does not have the flicker of relative fast moving and background high light between the transceiver, the result of the image after subtracting each other is, if LED is bright or dark during adjacent IMAQ, to have only seldom bright spot on the entire image, if and adjacent image is gathered when LED is bright and dark respectively, the result who subtracts each other back output so will present the hot spot of outstanding LED.At F
n(u, v), the width of cloth V that the adjacent bright spot of middle selection is maximum
n(u, v), to V
n(u v) carries out pattern recognition, and just very easy it is distinguished obtains its particular location coordinate (u on imageing sensor
i, v
i) i=1 wherein, 2,3 ..., M.M is exactly the picture dot quantity under LED covers.These picture dots are all to same LED light signal response, so its output signal is also basic identical.According to the power or the situation of picture dot in hot spot of signal, can select to export maximum one or middle one, also can select to export a plurality of, a plurality of output signal additions can be obtained diversity gain.
No matter to the imageing sensor of what type, increasing the output selection function is not the thing of difficulty.One of straightforward procedure that output is selected is that the shift register among Fig. 2 (2-3) is replaced with Fig. 4 circuit.Fig. 4 combines shift register with MUX, realize the position selection function.The method that realizes is that each output of shift register (4-1) is connected to except being connected to next bit on the multidiameter option switch 4-2 simultaneously.Multidiameter option switch can select one the road or a few road output in numerous input channels.4-2 is a kind of high-speed analog switch, has only shown that for expression is convenient one the tunnel exports among the figure, virtually completely can be configured to select simultaneously the output of several roads.4-1 and 4-2 each the input all distinguish the correspondence the row picture dot of imageing sensor.Like this as the position coordinates (u that has determined LED
i, v
i) after, suppose and will in M picture dot, select a picture dot i=K output, so row address decoder (2-2) is arranged on u
K, (4-2) is arranged on v with multidiameter option switch
K, just can export picture dot (u continuously
K, v
K) signal.
No matter to still the take a sample imageing sensor of output of the area array sensor that can export continuously, output channel is focused on one or only several picture dot from whole picture dots solved the problem that output is selected, but realize high-speed communication, to the also essential discrete sampling of output and the stationary problem of illumination pulse of solving of the imageing sensor of sampling output.
In order to set forth this way to solve the problem, suppose that the modulation system that optical communication is adopted is more representative pulse amplitude modulation (PAM), photo-emission source can send the pulse that amplitude does not wait with fixing cycle and pulse duration when communicating by letter so, and one or long number information are represented in the classification of neglecting greatly of amplitude.As can be divided into 4 grades the time, each pulse can be represented 2bit information, and when only needing represent 1bit information, deteriorates to the OOK modulation, promptly represents 0 or 1 with having or not of pulse.To the requirement of the impulsive synchronization of this modulation system sampling is initial moment when each pulse period, and sample circuit starts the electric charge cumulative process of photoelectric conversion unit, and the result that when pulse or end cycle, will the accumulate output of taking a sample.
Fig. 6 shows a kind of situation that reaches the ideal synchronisation state.The corresponding data flow 6-1 that will send, the light pulse after the OOK modulation is shown in 6-2.And if employing PAM modulates, corresponding data stream 6-3, the optical pulse waveform after the modulation should be shown in 6-4.6-5 is the synchronized sampling trigger impulse, and its forward position starts the photoelectric conversion process of the photodetector of picture dot, and along triggering output procedure, with the electric charge of detector accumulation, perhaps voltage (if changing) is transferred on the output circuit thereafter.
With PAM modulation signal 6-3 is example, at t1 constantly, light pulse arrives on the imageing sensor, this moment, sampled signal 6-5 started, optical-electrical converter on the imageing sensor begins that light energy is converted to electric charge and accumulates, by the time the t2 that light pulse disappears shifts output with its signal when sampled signal resets optical-electrical converter constantly, obtains the pulse signal between the t2 and t3 shown in 6-7.So the cycle continues, and light pulse sequence 6-4 is converted into electric impulse signal sequence 6-7 output.And, then can be converted to electric impulse signal 6-6 output to light pulse sequence 6-2.
The phase place strict synchronism of sampled signal 6-5 and light pulse 6-4 except the correct collection that guarantees signal, also can reduce to cross because of sample trigger being later than the influence to output signal of ambient noise that the pulse trailing edge introduces.This is because after the light pulse disappearance, surround lighting does not disappear, and still can have photoelectric conversion process.
Obtain above-mentioned synchronous regime, receiving terminal need know when arrived light pulse undoubtedly, but before not obtaining this light pulse, it can't be known again.Therefore the way that needs the employing code acquisition to follow the tracks of then.
Fig. 7 shows the lock-out pulse phase capturing circuit of the present invention's structure and forms, and is a closed loop Adjustment System.7-1 presentation video transducer and peripheral output circuit thereof etc., after imageing sensor receives light pulse signal, output signal U under the triggering of control wave Pt.The size of U is except outside the Pass having with irradiates light intensity, and is also relevant with the phase place of triggering signal Pt.The Pt signal comes from pulse signal generator (7-6).
The signal U of imageing sensor output becomes digital signal through ADC A-D converter (7-3) after by peak holding circuit (7-2) shaping.This signal divides two-way output, and one the tunnel directly delivers to amplitude comparator (7-4), and one tunnel signal P2 that produces after the time through delayer (7-5) delay T also delivers to this amplitude comparator, and T is the cycle time of light pulse.Amplitude comparator is these two signal contrast, produce one with P1, the relevant signal S of P2 amplitude.The input-output characteristic of amplitude comparator as shown in Figure 8, △=P1-P2 wherein.Pulse generator (7-5) changes the phase shift of the pulse that produces according to S: when S＞0, output signal is becoming big, illustrate that the phase place adjustment is in the right direction, and the phase place continuation of pulse Pt is along former adjustment direction change; When S＜0, output signal is diminishing, and it is wrong to illustrate that phase place is adjusted direction, and the phase place of pulse Pt should contrary former adjustment direction change; During S=0, illustrate that signal is on the synchronous points, do not need to change.
The acquisition procedure of lock-out pulse phase place now is described with Fig. 9.What suppose communication light source LED transmission at first is the preamble pulse of setting up correspondence, and the cycle is that T, pulsewidth are τ, shown in 9-1.Pulse generator 7-5 at first produces an inceptive impulse of arbitrary phase, as first pulse in the 9-2 sequence, remove to trigger the electric charge cumulative process that imageing sensor enters opto-electronic conversion, shown in 9-3, then in the trailing edge output signal of Pt, shown in first pulse of 9-4, and optical-electrical converter resetted.The output pulse amplitude of 9-4 is proportional to width overlapping time between Pt pulse 9-2 and the input optical pulse 9-1.This moment is because P2 not output still thinks 0, thus △=P1-P2＞0, S＞0.But because the reference point that initial condition does not also have phase place to adjust, the phase place of next pulse that therefore can stipulate Pt generates second pulse among the 9-2 like this with respect to δ value of previous pulse daley.The signal U that exports behind end-of-pulsing is second pulse of 9-4.This moment, the output of amplitude comparator was exported a minus signal S according to the difference of former and later two pulse amplitudes, and therefore, the next Pt pulse of pulse generator output will be adjusted phase place in the opposite direction, produce the 3rd pulse.Because the 3rd pulse is than second more approaching accurate phase place, so its output change is big, as the 3rd pulse of 9-4.This moment, signal S was for just, so signal generator continues to adjust phase place along former adjustment direction the 4th pulse of generation 9-2.With this recursion, produce the 5th output pulse.This is maximum outgoing position, but circuit and not knowing satisfy and on next trigger impulse, produce excessive phase place adjustment, cause output pulse amplitude to reduce.At this moment, because S＜0, next trigger impulse phase place is to adjusting in the other direction.Owing to had been found that possible maximum point 9-5, so amplitude comparator will adjust magnitude and diminish, and make it progressively get back to maximum point and settle out the Phase Tracking process that enters.After preamble pulse finished, transmitting terminal can send data sequence (9-6), and that after this produce will be data-signal (9-7).
Because what follow the tracks of is impulse phase, and in existence interference at the zero point of S, the adjustment step-length of Pt impulse phase influences synchronization acquistion time and precision, but can realize tenacious tracking as long as revise parameter in practice.
So far, one embodiment of the invention have obtained describing substantially clearly from system's formation, feature functionality, circuit composition and algorithm etc.
The given above-mentioned embodiment of the present invention just realizes one of method of function proposed by the invention.The circuit and the algorithm of the same function of well-known realization are diversified; in different communication network application; the type of face array photoelectric sensor, the light signal form that is received also may be different, therefore do not break away from basic conception of the present invention and protection range for realizing adopting face array photoelectric sensor to carry out selectivity output and synchronized sampling that high speed optical communication introduces.
Claims (2)
1. realize the reception of communicate optical signal, the device of output with face array photoelectric sensor for one kind, mainly constitute by imaging optical system, face array photoelectric sensor, output select circuit, output control unit and signal processing unit:
The direct output of each pixel of face array photoelectric sensor is controlled by output select circuit, can select the output of whole pixel signals, also can Dynamic Selection specific any one or the output of arbitrary portion pixel signal and remaining pixel is not exported; The output control unit of face array photoelectric sensor makes the signal output of selected pixel and the Communication ray that drops on this pixel shine impulsive synchronization, it triggers opto-electronic conversion and the output sampling constantly has definite time relationship with the illumination pulse, when arriving, the illumination pulse starts opto-electronic conversion, during the illumination end-of-pulsing, the output photoelectric conversion signal;
Output select circuit, control unit are assisted down signal processing unit, select corresponding pixel output signal according to the image space of communication light source on face array photoelectric sensor:
Signal processing unit at first receives complete picture signal, according to the shape facility that is reflected in the communication light source imaging on the output image, determines the pixel of its present position correspondence on face array photoelectric sensor; Perhaps, communication light source is luminous with the frequency of agreement, the output that makes face array photoelectric sensor becomes can collect respectively in the picture frame the different situations of light source when bright and dark in difference, signal processing unit is by the phase reducing to light and shade two frame image datas, highlight the position of communication light source, determine its pairing pixel on face array photoelectric sensor thus; After the output pixel is selected, the row selection signal of control unit chain of command array photoelectric sensor is exported the signal that selected pixel is expert at line by line and is outputed in the capable register of joint face array photoelectric sensor row output, the size of row register is identical with the columns of face array photoelectric sensor, the row register is connected to the multidiameter option switch of a same way, and multidiameter option switch is selected the row output signal at corresponding selected pixel place by control unit.
2. the synchronous synchronization acquistion tracking circuit by control unit described in the claim 1 realizes that synchronization acquistion tracking circuit output sampling pulse triggers face array photoelectric sensor output.
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| US10284293B2 (en) | 2016-09-23 | 2019-05-07 | Qualcomm Incorporated | Selective pixel activation for light-based communication processing |
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| EP2478648B8 (en) * | 2009-09-18 | 2017-12-13 | InterDigital Patent Holdings, Inc. | Method and apparatus for dimming with rate control for visible light communications (vlc) |
| CN103327317B (en) * | 2012-03-20 | 2017-10-27 | 财团法人工业技术研究院 | Optic communication transmission and reception device and method and optical communication system and method |
| WO2015014237A1 (en) * | 2013-07-31 | 2015-02-05 | 深圳光启创新技术有限公司 | Method and apparatus for receiving visible light signal |
| CN103795467B (en) * | 2013-11-05 | 2015-03-11 | 深圳光启创新技术有限公司 | Method and apparatus for identifying visible light communication signal received by camera |
| CN103905179B (en) * | 2014-04-11 | 2015-03-11 | 北京理工大学 | Method and device for dynamically adjusting phase of electric trigger clock |
| CN104567743A (en) * | 2015-01-08 | 2015-04-29 | 佛山轻子精密测控技术有限公司 | Angle displacement measurement device and measurement method thereof |
| US9971921B2 (en) * | 2015-08-07 | 2018-05-15 | Shanghai Oxi Technology Co., Ltd | Fingerprint image sensor and method for optical wireless communications using the same |
| CN105721801B (en) * | 2016-01-26 | 2018-07-17 | 西安电子科技大学 | The cmos image sensor dual mode communication of integrated photodetector receives system |
| CN106597366B (en) * | 2016-11-25 | 2019-04-19 | 湖北三江航天万峰科技发展有限公司 | A kind of signal processing system of photodetector |
| CN109104243B (en) * | 2018-08-01 | 2020-11-03 | 北方工业大学 | Pixel communication method, information sending terminal and information receiving terminal |
| CN109842875A (en) * | 2019-03-28 | 2019-06-04 | 贵州省计量测试院 | A kind of calamity emergency Public Information Issuance System based on visible light communication technology |
| CN112272055B (en) * | 2020-09-30 | 2022-02-18 | 东莞职业技术学院 | OOK modulation method and modulator of mobile visible light communication receiver |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10284293B2 (en) | 2016-09-23 | 2019-05-07 | Qualcomm Incorporated | Selective pixel activation for light-based communication processing |
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