CN104570275B - A kind of autofocus system and method - Google Patents
A kind of autofocus system and method Download PDFInfo
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- CN104570275B CN104570275B CN201410784698.0A CN201410784698A CN104570275B CN 104570275 B CN104570275 B CN 104570275B CN 201410784698 A CN201410784698 A CN 201410784698A CN 104570275 B CN104570275 B CN 104570275B
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/28—Systems for automatic generation of focusing signals
- G02B7/282—Autofocusing of zoom lenses
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/28—Systems for automatic generation of focusing signals
- G02B7/285—Systems for automatic generation of focusing signals including two or more different focus detection devices, e.g. both an active and a passive focus detecting device
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Abstract
The present invention relates to visible light communication field, discloses a kind of autofocus system and method.In the present invention, AFC system is comprising light collecting element, measurement photodetector unit, measurement d.c. integration circuit, microprocessor (MCU) and stepper motor；The optical signal of reception is converged to measure photodetector unit, the flashlight that optical signal sends comprising LED by light collecting element；The optical signal of reception is converted to measurement electric signal by measurement photodetector unit；Measurement d.c. integration circuit is integrated and exports result to MCU to measuring the measurement DC signal in electric signal；MCU controls light collecting element to carry out moving back and forth position when being maximum up to its integral result for being parked in measurement DC signal in the distance of swimming according to the data for receiving by stepper motor；The scope of the wherein distance of swimming be from light collecting element away from measurement photodetector unit minimum position to maximum position.So, allow visible light communication system that most strong visible light signal is obtained automatically, improve accuracy and the reliability of system.
Description
Technical field
The present invention relates to visible light communication field, more particularly to a kind of focusing (Continuous automatic automatically
Focus, abbreviation AFC) system and method.
Background technology
White light LEDs (Light-Emitting Diode, light emitting diode) have luminous efficiency as a kind of solid state light emitter
High, size is little, life-span length the advantages of, the lighting apparatus for replacing traditional is become environmental protection lighting light source of future generation.As a kind of half
Conductor photonic device, the fast response characteristic of white light LEDs make it have the feature of High Speed Modulation, can cannot with human eye by signal
The velocity modulation of perception carries out data transmission on LED light source.LED-based These characteristics, generate a kind of coupling of depth and shine
The bright new technology with data transfer, you can see optical communication technique (Visible Light Communication, abbreviation VLC).
VLC technology as a kind of light wireless communication technology have transmission power high, without the need for frequency spectrum application, bandwidth high, nothing electromagnetic interference simultaneously
And safe and reliable the advantages of, can be used as the supplement of the twireless radio-frequency communication technology of frequency spectrum growing tension.
Infrared radio optical communication system is compared, therefore the light 101 that white light LEDs send in VLC system launched to eye-safe
Power can be very high, but, as the light-emitting mode of LED follows lambert's divergent mode, from light source compared with distant location, even if having
Higher transmission power, light intensity are still very weak.Wherein, VLC system block diagram is as shown in Figure 1.And, VLC system is designed to mostly
Light intensity modulation, direct detection system (Intensity Modulation/Direct Detection, abbreviation IM/DD), receive
The power of the optical signal that the Photoelectric Detection chip of machine is received will directly determine that can whole system normally work.Work as receiver
The optical signal that receives of Photoelectric Detection chip very weak when, follow-up process circuit will occur larger deviation, it is impossible to ensure
The accurate delivery of information.In order to solve this problem, in the preposition light collecting element of Photoelectric Detection chip, using the light collecting element
Optical signal is converged on Photoelectric Detection chip, to strengthen the light intensity that Photoelectric Detection chip is received, it is ensured that the accurate biography of information
Defeated.
However, in visible light communication, in some wave band in the white light for generally signal modulation to LED being sent, than
Can such as modulate the signal in blue light, wherein the wave-length coverage of blue light is 450-460nm, it is also possible to modulate the signal to other
In wave band, such as, red：622～597nm, orange：597～577nm, yellow：577～492nm, green：492～455nm,
Indigo color：455～350nm.And the focal length of light collecting element can change with the change of the wavelength of incident light, if light collecting element
If position is fixed, the optical signal of a certain wave band can only be focused on Photoelectric Detection chip, and the optical signal to its all band
Effect is not then good, and poor compatibility, application are restricted.And, even if only the optical signal to a certain wave band proves effective, because wave band tool
The light collecting effect for having certain wave-length coverage, light collecting element also can be affected because of different optical signal sources, so as to affect system
Accuracy and reliability.
Content of the invention
It is an object of the invention to provide a kind of autofocus system and method so that visible light communication system can be automatic
Most strong visible light signal is obtained, accuracy and the reliability of system is improved, and compatibility is strong.
For solving above-mentioned technical problem, the invention provides a kind of AFC system, comprising：Light collecting element, measurement Photoelectric Detection
Unit, measurement d.c. integration circuit, Micro-processor MCV and stepper motor；
When LED is opened, the light collecting element, for being focused at the measurement Photoelectric Detection list by the optical signal of reception
In unit；Wherein, the flashlight that the optical signal is sent comprising LED；
The measurement photodetector unit, for being converted to measurement electric signal by the optical signal for receiving；Wherein, described
Measurement electric signal is comprising measurement ac signal and measurement DC signal；
The measurement d.c. integration circuit, for obtaining the measurement DC signal and inciting somebody to action from the measurement electric signal
Integral result to the measurement DC signal is exported to the MCU；
The MCU, for the integral result according to the measurement DC signal for receiving, by the stepper motor control
Make the light collecting element to be moved back and forth in the distance of swimming, until the light collecting element is parked in and the measurement DC signal
Integral result is the corresponding position of maximum；
Wherein, the scope of the distance of swimming is the minimum position from the light collecting element away from the measurement photodetector unit
To maximum position.
Present invention also offers a kind of AFC method, comprises the steps of：
When the LED is opened, the optical signal of reception is focused at measurement photoelectricity by AFC system built-in light collecting element
In detector unit；Wherein, the flashlight that the optical signal is sent comprising LED；
The optical signal for receiving is converted to measurement electric signal by the measurement photodetector unit；Wherein, the survey
Amount electric signal is comprising measurement ac signal and measurement DC signal；
The measurement DC signal will be to described is obtained from the measurement electric signal by measurement d.c. integration circuit
The integral result of measurement DC signal is exported to Micro-processor MCV；
By the MCU according to the integral result of the measurement DC signal for receiving, controlled by stepper motor described
Light collecting element is moved back and forth in the distance of swimming, until the light collecting element is parked in the integration knot with the measurement DC signal
Fruit is the corresponding position of maximum；
Wherein, the scope of the distance of swimming is the minimum position from the light collecting element away from the measurement photodetector unit
To maximum position.
Embodiment of the present invention in terms of existing technologies, is the signal that will be sent comprising LED using light collecting element
The optical signal of light is focused in measurement photodetector unit, strengthens the intensity of the optical signal that measurement photodetector unit is detected,
To improve accuracy and the reliability of optical signal processing circuit；When the initial position at light collecting element place is to measurement Photoelectric Detection list
Unit distance be not light collecting element focal length (i.e. light collecting element focus not measure photodetector unit on) when, it is,
When the intensity of the optical signal that measurement photodetector unit is detected not is maximum, straight according to measurement using microprocessor (MCU)
The integral result control stepper motor of the measurement DC signal of stream integrating circuit output, stepper motor is in the control of microprocessor
It is maximum that lower driving light collecting element is carried out moving back and forth up to the integral result for measuring DC signal in the distance of swimming, now,
The maximum intensity of the optical signal that measurement photodetector unit is detected, wherein, the integral result for measuring DC signal characterizes light
The intensity of signal；And, the optical signal for any wavelength in visible ray detects can measurement photodetector unit
Light intensity is maximum.So so that visible light communication system can obtain most strong visible light signal automatically, the accuracy of system is improved
With reliability, and compatibility is strong.
In addition, the default initial position of the light collecting element is the minimum position away from the measurement photodetector unit
Or maximum position.When the default initial position of light collecting element is the maximum position away from measurement photodetector unit, i.e.,
When light collecting element range measurement photodetector unit is farthest, then microprocessor then control light collecting element by remote by stepper motor and
Near-earth is moved to nearest away from minimum position, i.e. the light collecting element range measurement photodetector unit of measurement photodetector unit
Place, microprocessor measure the change of the integral result of DC signal in moving process and (measure photoelectricity according to light collecting element
The change of the light intensity that detector unit is detected) find out and integral result maximum (the i.e. measurement light electric-examination for measuring DC signal
Survey the maximum of light intensity that unit is detected) the position X of corresponding light collecting element0, and light collecting element is controlled by stepper motor
Position X is from the close-by examples to those far off returned0, that is, the intensity of optical signal that measurement photodetector unit is detected reached maximum；
When the default initial position of light collecting element is the minimum position away from measurement photodetector unit, otherwise then.So, pass through
The default initial position of the two light collecting elements can control stepper motor to be in light collecting element by microprocessor to be made
The integral result of measurement DC signal is on the position of maximum, it is ensured that the flexibility of embodiment of the present invention.
In addition, before the LED is opened, the AFC system is used for detecting ambient light, and records the inspection of the ambient light
Survey result；When the LED is opened, the optical signal is comprising the ambient light and the flashlight；The AFC system is used for
The testing result of the ambient light is deducted from the testing result of the optical signal, obtains the testing result of the flashlight, and
According to the testing result of the flashlight, the light collecting element is controlled back and forth to be moved in the distance of swimming by the stepper motor
Dynamic, until it is the corresponding position of maximum that the light collecting element is parked in the testing result of the flashlight.
It is contemplated that also there is ambient light in actual applications, before LED is opened, using measurement Photoelectric Detection list
Intensity (the i.e. integration knot of reference DC signal of whole ambient light when unit's detection light collecting element is moved in the range of the distance of swimming
Really)；After LED is opened, the testing result of ambient light is deducted using MCU from the testing result of optical signal, obtain signal
The testing result of light, i.e., accordingly eliminate ambient light in the optical signal for detecting from measurement photodetector unit, obtain pure
The flashlight that LED sends；According to the testing result of flashlight, it is in light collecting element and detects with measurement photodetector unit
Flashlight intensity be the corresponding position of maximum on, this eliminates impact of the ambient light to system, further increase
The accuracy and reliability of system.
In addition, also comprising reference photodetector unit and reference d.c. integration circuit；The reference photodetector unit, uses
In the ambient light is converted to reference electric signal；Wherein, the reference electric signal is straight comprising reference ac signal and reference
Stream electric signal；The reference d.c. integration circuit, for obtaining the reference DC signal from the reference electric signal, and
The integral result of the reference DC signal will be exported to the MCU；Wherein, the integration knot of the reference DC signal
Fruit is the testing result of the ambient light.
Due to before LED is opened, being using reference photodetector unit detection ambient light and to be converted to reference telecommunications
Number, and reference DC signal is obtained from reference electric signal using reference d.c. integration circuit, and to reference DC signal
It is integrated, the burden of measurement photodetector unit is so alleviated, extends the life-span of measurement photodetector unit, it is ensured that
The flexibility of embodiment of the present invention.
In addition, the measurement d.c. integration circuit, the Micro-processor MCV are integrated in photoproduction telecommunications with the stepper motor
On the printing board PCB of number process circuit；The measurement photodetector unit is integrated in Photoelectric Detection chip with the PCB
On.As measurement d.c. integration circuit, MCU and stepper motor being all integrated in PCB (Printed Circuit Board, printing
Circuit board) on, and measurement photodetector unit is integrated on Photoelectric Detection chip, so with PCB, greatly reduce system institute
The area for accounting for, has saved space, is conducive to the integrated of system.
In addition, also including polyvinylchloride framework；The light collecting element is arranged on the photoelectricity by the PVC framework
Above detection chip.As PVC (Polyvinyl chloride polymer, polyvinyl chloride) framework has elasticity, not only make
Light collecting element can be adjusted to the distance of measurement photodetector unit, can support light collecting element again, it is ensured that the present invention is implemented
The feasibility of mode.
Description of the drawings
Fig. 1 be according to visible light communication system structural representation in prior art；
Fig. 2 is the AFC system structural representation according to first embodiment of the invention；
Fig. 3 be according to the Photoelectric Detection chip structure schematic diagram in first embodiment of the invention；
Fig. 4 is the AFC system structural representation according to third embodiment of the invention；
Fig. 5 is the AFC method flow diagram according to four embodiment of the invention；
Fig. 6 is the AFC method flow diagram according to fifth embodiment of the invention.
Specific embodiment
For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with each reality of the accompanying drawing to the present invention
The mode of applying is explained in detail.However, it will be understood by those skilled in the art that in each embodiment of the present invention,
In order that reader more fully understands the application and proposes many ins and outs.But, even if there is no these ins and outs and base
Many variations and modification in following embodiment, it is also possible to realize each claim of the application technical side required for protection
Case.
The first embodiment of the present invention is related to a kind of AFC system, and concrete structure is as shown in Fig. 2 include：Light collecting element
201st, measurement photodetector unit, measurement d.c. integration circuit, microprocessor (MCU) and stepper motor.
Specifically, when LED is opened, the optical signal of reception is focused at measurement photodetector unit by light collecting element
On；Wherein, the flashlight 101 that optical signal is mainly sent comprising LED, flashlight 101 carry the information of transmission.Due to light harvesting
Element has converging action to light, therefore measurement photodetector unit unit area on detect through light collecting element assemble after
The light intensity of optical signal strengthened, particularly light collecting element focus when measuring in photodetector unit, measure photoelectricity
The optical signal light intensity that detector unit is detected is maximum, it is, measuring the light intensity of the flashlight that photodetector unit is detected
Larger.
In the present embodiment, light collecting element can be on default initial position.Wherein, default initial position can
Think the minimum position away from measurement photodetector unit, or away from the maximum position of measurement photodetector unit.Collection
Optical element is in default initial position, although the light intensity of the optical signal being focused in measurement photodetector unit can be than not setting collection
Optical element is strong, but not necessarily maximum.
The optical signal of reception is converted to measurement electric signal by measurement photodetector unit；Wherein, measurement electric signal is comprising survey
Amount ac signal and measurement DC signal.The optical signal for receiving is converted to after electric signal just by measurement photodetector unit
Can be processed by follow-up process circuit.As LED is exchange electric drive, so, through measuring photodetector unit conversion
Measurement electric signal afterwards includes two kinds of compositions：Measurement ac signal and measurement DC signal.
Measurement d.c. integration circuit obtains measurement DC signal will be to measurement DC signal from measurement electric signal
Integral result export to MCU.Measurement d.c. integration circuit first obtains measurement DC signal from measurement electric signal, and to surveying
Amount direct current signal is integrated drawing the mean value of measurement direct current signal, that is, measures the integral result of DC signal, wherein, survey
The mean value of amount direct current signal can characterize the light intensity of the optical signal that measurement photodetector unit is received.Measurement d.c. integration circuit
The integral result of measurement DC signal is exported to MCU, so that MCU adjusts the position of light collecting element accordingly.
MCU is generated control signal and exports to stepper motor according to the integral result of the measurement DC signal for receiving；Step
Entering motor controls light collecting element to be moved back and forth in the distance of swimming with default initial position as starting point according to control signal, until
It is the corresponding position of maximum that light collecting element is parked in the integral result of measurement DC signal, now, measures Photoelectric Detection list
The maximum intensity of the optical signal that unit detects, the light intensity of the flashlight for detecting are also larger.
As the light intensity of the optical signal detected according to measurement photodetector unit using MCU passes through stepper motor domination set
The position of optical element, the maximum intensity of the optical signal for detecting measurement photodetector unit, wherein, optical signal mainly includes
The flashlight that LED sends；And, the optical signal for any wavelength in visible ray examines can measurement photodetector unit
The light intensity for measuring is maximum, and the situation with the visible ray of different wave length as carrier wave is all suitable for.So, it is seen that optical communication system is permissible
Automatically most strong visible light signal is obtained, accuracy and the reliability of system is improved, and compatibility is strong.
It is exemplified below：
When the default initial position of light collecting element is the maximum position away from measurement photodetector unit, i.e., light harvesting is first
When part range measurement photodetector unit is farthest, optical signal measures what photodetector unit was received after light collecting element convergence
The light intensity of optical signal is still weaker；Now, through measuring the measurement direct current in the measurement electric signal that photodetector unit is exported
Signal is also weaker；Measurement d.c. integration circuit obtains measurement DC signal and is integrated obtaining to measuring DC signal
The integral result of measurement DC signal, wherein, the integral result for measuring DC signal can characterize the intensity of optical signal；Micro-
According to the integral result of measurement DC signal, processor (MCU) knows that the light collecting element through being in current location is focused at measurement
Light intensity in photodetector unit is not maximum, just generates control signal, control light collecting element by remote by stepper motor and
Near-earth, be moved to length by length away from measurement photodetector unit minimum position, i.e. light collecting element range measurement light electric-examination
Survey unit most nearby.In this process, light collecting element is often moved and is moved a step, and microprocessor (MCU) is just according to measurement direct current telecommunications
Number integral result record measurement photodetector unit on receive light intensity (I) and the corresponding position of light collecting element (X)；Microprocessor
Device (MCU) measures the change of the integral result of DC signal in moving process and (measures Photoelectric Detection according to light collecting element
The change of the light intensity (I) that unit is detected) find out with measurement DC signal integral result maximum (i.e. measure Photoelectric Detection
The maximum (Imax) of the light intensity that unit is detected) corresponding light collecting element position (X0), and pass through stepper motor domination set
Optical element from the close-by examples to those far off returns the position (X0), that is, the focus of light collecting element is made in measurement photodetector unit, this
Sample, the intensity for measuring the optical signal that photodetector unit is detected have reached maximum；Default initial bit when light collecting element
When being set to the minimum position away from measurement photodetector unit, otherwise then.So, by the default first of the two light collecting elements
Beginning position can control stepper motor to be in light collecting element by microprocessor makes the integral result of measurement DC signal
For on the position of maximum, it is ensured that the flexibility of embodiment of the present invention.
In actual applications, measurement d.c. integration circuit, Micro-processor MCV and stepper motor can also be integrated in photoproduction
On the printing board PCB of electric signal processing circuit, and measurement photodetector unit is integrated in Photoelectric Detection chip with PCB
On.As measurement d.c. integration circuit, MCU and stepper motor are all integrated on PCB, and will measurement photodetector unit with
PCB is integrated on Photoelectric Detection chip, so, greatly reduces the area shared by system, has saved space, is conducive to system
Integrated.
And, in actual applications, polyvinylchloride framework can also be included, concrete as shown in figure 3, light collecting element is logical
PVC framework 302 is crossed installed in 301 top of Photoelectric Detection chip.As PVC framework 302 has elasticity, not only arrive light collecting element
Measurement photodetector unit distance can adjust, light collecting element can be supported again, it is ensured that embodiment of the present invention feasible
Property.
It is noted that in actual applications, light collecting element can be lens or lens group.Wherein, Fresnel is saturating
Mirror condenser performance is excellent, and the uniformity is preferable, and cheap, is a kind of considerable selection.
Compared with prior art, it is, using light collecting element, the optical signal of the flashlight sent comprising LED is focused at survey
In amount photodetector unit, strengthen the intensity of the optical signal that measurement photodetector unit is detected, to improve optical signal prosessing electricity
The accuracy and reliability on road；When the initial position that light collecting element is located is not that light harvesting is first to the distance of measurement photodetector unit
Part focal length (i.e. light collecting element focus not measure photodetector unit on) when, it is, measurement photodetector unit inspection
When the intensity of the optical signal for measuring not is maximum, using microprocessor according to the measurement direct current for measuring d.c. integration circuit output
The integral result control stepper motor of electric signal, stepper motor drive light collecting element to enter in the distance of swimming under control of the microprocessor
It is maximum that row is moved back and forth up to the integral result for measuring DC signal, now, measures what photodetector unit was detected
The maximum intensity of optical signal, wherein, the integral result for measuring DC signal characterizes the intensity of optical signal；And, for visible
Appoint the optical signal of any wavelength that the light intensity that measurement photodetector unit is detected can be made maximum in light, to different wave length
Visible ray is all suitable for for the situation of carrier wave.So so that visible light communication system can obtain most strong visible light signal automatically,
The accuracy and reliability of raising system, and compatibility is strong.
Second embodiment of the present invention is related to a kind of AFC system.Second embodiment is on the basis of first embodiment
On made to improve further, mainly the improvement is that：In second embodiment of the invention, it is contemplated that the impact of ambient light,
Before LED is opened, AFC system is used for detecting ambient light that, when LED is opened, AFC system to be from the testing result of optical signal
Deduct the testing result of ambient light, this eliminates impact of the ambient light to system, further increase the accuracy of system with
Reliability.
In the present embodiment, it is that impact of the ambient light to system is eliminated, first, before LED sends flashlight, utilizes
The intensity of whole ambient light detection knot is recorded when measurement photodetector unit detection light collecting element is moved in the range of the distance of swimming
Really.Specifically, ambient light is converted to reference electric signal with measurement photodetector unit, wherein, includes in reference electric signal
Reference ac signal and reference DC signal；Reference direct current is obtained from reference electric signal using measurement d.c. integration circuit
Electric signal simultaneously will be exported to MCU to the integral result of reference DC signal, for reference, wherein, reference DC signal
Integral result is the testing result of ambient light.
Then, when LED is opened, recycle light collecting element that the optical signal of reception is focused at measurement photodetector unit
On, wherein, the flashlight that optical signal is sent with LED comprising ambient light；The optical signal for receiving is changed by measurement photodetector unit
For electric signal is measured, and electric signal is measured comprising measurement ac signal and measurement DC signal；Measurement d.c. integration circuit
Measurement DC signal is obtained from measurement electric signal and the integral result for measuring DC signal will be exported to MCU；MCU from
The testing result of ambient light is deducted in the testing result of optical signal, obtains the testing result of flashlight, and the inspection according to flashlight
Result is surveyed, is generated control signal and exports to stepper motor, that is, the control generated after the impact for eliminating ambient light is believed
Number export to stepper motor；Stepper motor controls light collecting element to carry out moving back and forth according to control signal until measurement Photoelectric Detection
The intensity of the flashlight that unit is detected is maximum.MCU controls light collecting element to be moved back and forth by stepper motor
Process, similar with the process in measurement embodiment, will not be described here.
It is contemplated that the presence of practical application ambient light, first detects ambient light using AFC system and records detection knot
Really, the testing result for connecing survey result, obtaining pure flashlight of ambient light then is deducted from the testing result of optical signal；According to
The testing result of flashlight, the intensity for making light collecting element be in the flashlight detected with measurement photodetector unit are maximum
On corresponding position, impact of the ambient light to system is this eliminates, further increase accuracy and the reliability of system.
Third embodiment of the invention is related to a kind of AFC system.3rd embodiment is roughly the same with second embodiment,
It is in place of the main distinction：In this second embodiment, before LED unlatching, straight using measurement photodetector unit and measurement
Stream integrating circuit ambient light 401.And in third embodiment of the invention, also comprising reference photodetector unit and reference
D.c. integration circuit, concrete as shown in figure 4, using reference photodetector unit and reference d.c. integration processing of circuit ambient light
401, the burden of measurement photodetector unit so, is alleviated, extends the life-span of measurement photodetector unit, it is ensured that this
The flexibility of bright embodiment.
Specifically, in embodiments, before LED is opened, ambient light 401 is changed by reference photodetector unit
For reference electric signal；Wherein, reference electric signal is comprising reference ac signal and reference DC signal；Reference d.c. integration electricity
Road obtains reference DC signal from reference electric signal and the integral result of reference DC signal will be exported to MCU.?
After opening LED, light collecting element is focused at the optical signal of reception in measurement photodetector unit, and wherein, optical signal includes
The flashlight 101 that ambient light 401 is sent with LED；The optical signal of reception is converted to measurement electric signal by measurement photodetector unit,
And electric signal is measured comprising measurement ac signal and measurement DC signal；Measurement d.c. integration circuit is from measurement electric signal
Obtain measurement DC signal and the integral result for measuring DC signal will be exported to MCU；MCU is tied from the detection of optical signal
The testing result of ambient light is deducted in fruit, is obtained the testing result of flashlight, and the testing result according to flashlight, is generated control
Signal is simultaneously exported to stepper motor；Stepper motor controls light collecting element to carry out moving back and forth according to control signal until measurement photoelectricity
The intensity of the flashlight that detector unit is detected is maximum.MCU controls light collecting element to be moved back and forth by stepper motor
Process, with measurement embodiment in the process similar, will not be described here.
Due to before LED is opened, being using reference photodetector unit detection ambient light and to be converted to reference telecommunications
Number, and reference DC signal is obtained from reference electric signal using reference d.c. integration circuit, and to reference DC signal
It is integrated；The burden of measurement photodetector unit is so alleviated, extends the life-span of measurement photodetector unit, it is ensured that
The flexibility of embodiment of the present invention.
Four embodiment of the invention is related to a kind of AFC method, and idiographic flow is as shown in figure 5, comprise the steps of：
The optical signal of reception, when LED is opened, is focused at measurement by the built-in light collecting element of AFC system by step 501
In photodetector unit；Wherein, the flashlight that optical signal is sent comprising LED.
The optical signal of reception is converted to measurement electric signal by measurement photodetector unit by step 502；Wherein, electricity is measured
Signal is comprising measurement ac signal and measurement DC signal.
Step 503, obtains measurement DC signal will be to measuring by measurement d.c. integration circuit from measurement electric signal
The integral result of DC signal is exported to microprocessor (MCU).
Step 504, is generated control signal and exports to step according to the integral result of the measurement DC signal for receiving by MCU
Enter motor.
Step 505, controls light collecting element to be moved back and forth in the distance of swimming by stepper motor according to control signal, until collection
It is the corresponding position of maximum that optical element is parked in the integral result of measurement DC signal.
Wherein, the scope of the distance of swimming be from light collecting element away from measurement photodetector unit minimum position to maximum position；
And the default initial position of light collecting element is minimum position or the maximum position away from measurement photodetector unit.
It is seen that, present embodiment is the embodiment of the method corresponding with first embodiment, and present embodiment can be with
First embodiment is worked in coordination enforcement.The relevant technical details that mentions in first embodiment still have in the present embodiment
Effect, in order to reduce repetition, is repeated no more here.Correspondingly, the relevant technical details that mentions in present embodiment are also applicable in
In first embodiment.
5th embodiment of the present invention is related to a kind of AFC method, and idiographic flow is as shown in Figure 6.5th embodiment exists
Make to improve further on the basis of 4th embodiment, mainly theed improvement is that：In fifth embodiment of the invention, examine
Considered the impact of ambient light, LED open before, ambient light is detected by AFC system, when LED is opened, by AFC system from
The testing result of ambient light is deducted in the testing result of optical signal, is obtained the testing result of flashlight, be this eliminates ambient light
Impact to system, further increases accuracy and the reliability of system.
Specifically, in the present embodiment, comprise the steps of：
Step 601, before LED is opened, detects ambient light by AFC system, and records the testing result of ambient light.
Step 602, when LED is opened, is deducted the detection knot of ambient light from the testing result of optical signal by AFC system
Really, the testing result of flashlight is obtained.
Step 603, according to the testing result of flashlight, controls light collecting element to carry out in the distance of swimming back and forth by stepper motor
Mobile, until it is the corresponding position of maximum that light collecting element is parked in the testing result of flashlight.
As second embodiment is mutually corresponding with present embodiment, therefore present embodiment can be mutual with second embodiment
Match enforcement.The relevant technical details that mentions in second embodiment still effectively, are implemented second in the present embodiment
The technique effect that can be reached in mode is in the present embodiment similarly it is achieved that in order to reduce repetition, no longer go to live in the household of one's in-laws on getting married here
State.Correspondingly, the relevant technical details that mentions in present embodiment are also applicable in second embodiment.
Sixth embodiment of the invention is related to a kind of AFC method.6th embodiment is roughly the same with the 5th embodiment,
It is in place of the main distinction：In the 5th embodiment, by measurement photodetector unit and measurement d.c. integration processing of circuit ring
Border light.And in sixth embodiment of the invention, by reference photodetector unit and reference d.c. integration processing of circuit ambient light,
So, the burden of measurement photodetector unit is alleviated, extends the life-span of measurement photodetector unit, it is ensured that reality of the present invention
Apply the flexibility of mode.
Specifically, before LED unlatching, ambient light is detected by AFC system, and records the step of the testing result of ambient light
In rapid, comprising following sub-step：
First, ambient light is converted to reference electric signal by AFC system built-in reference photodetector unit；Wherein, join
Than electric signal comprising reference ac signal and reference DC signal.
Then, reference DC signal is obtained from reference electric signal by reference d.c. integration circuit, and will be straight to reference
The integral result of stream electric signal is exported to MCU.Wherein, the integral result of reference DC signal is the testing result of ambient light.
As the 3rd embodiment is mutually corresponding with present embodiment, therefore present embodiment can be mutual with the 3rd embodiment
Match enforcement.The relevant technical details that mentions in 3rd embodiment still effectively, are implemented the 3rd in the present embodiment
The technique effect that can be reached in mode is in the present embodiment similarly it is achieved that in order to reduce repetition, no longer go to live in the household of one's in-laws on getting married here
State.Correspondingly, the relevant technical details that mentions in present embodiment are also applicable in the 3rd embodiment.
Divide the step of various methods above, be intended merely to describe clear, can merge into when realizing a step or
Some steps are split, multiple steps are decomposed into, as long as comprising identical logical relation, all in the protection domain of this patent
Interior；To adding inessential modification in algorithm or in flow process or inessential design being introduced, but its algorithm is not changed
With the core design of flow process all in the protection domain of the patent.
It will be understood by those skilled in the art that the respective embodiments described above are to realize the specific embodiment of the present invention,
And in actual applications, can to which, various changes can be made in the form and details, without departing from the spirit and scope of the present invention.
Claims (10)
1. a kind of focusing AFC system automatically, is applied to visible light communication system, it is characterised in that include：Light collecting element, measurement
Photodetector unit, measurement d.c. integration circuit, Micro-processor MCV and stepper motor；
When LED is opened, the light collecting element, for being focused at the measurement photodetector unit by the optical signal of reception
On；Wherein, the flashlight that the optical signal is sent comprising LED；
The measurement photodetector unit, for being converted to measurement electric signal by the optical signal for receiving；Wherein, the measurement
Electric signal is comprising measurement ac signal and measurement DC signal；
The measurement d.c. integration circuit, for obtaining the measurement DC signal will be to institute from the measurement electric signal
The integral result for stating measurement DC signal is exported to the MCU；
The MCU, for the integral result according to the measurement DC signal for receiving, controls institute by the stepper motor
State light collecting element to be moved back and forth in the distance of swimming, until the light collecting element is parked in the integration with the measurement DC signal
As a result it is the corresponding position of maximum；
Wherein, the scope of the distance of swimming be from the light collecting element away from described measurement photodetector unit minimum position to most
Big position.
2. AFC system according to claim 1, it is characterised in that the default initial position of the light collecting element is remote
Minimum position or maximum position from the measurement photodetector unit.
3. AFC system according to claim 1, it is characterised in that before the LED is opened, the AFC system is used for
Detection ambient light, and record the testing result of the ambient light；
When the LED is opened, the optical signal is comprising the ambient light and the flashlight；The AFC system be used for from
The testing result of the ambient light is deducted in the testing result of the optical signal, obtains the testing result of the flashlight, and root
According to the testing result of the flashlight, the light collecting element is controlled to be moved back and forth in the distance of swimming by the stepper motor,
Until it is the corresponding position of maximum that the light collecting element is parked in the testing result of the flashlight.
4. AFC system according to claim 3, it is characterised in that also comprising reference photodetector unit and reference direct current
Integrating circuit；
The reference photodetector unit, for being converted to reference electric signal by the ambient light；Wherein, the reference electric signal
Comprising reference ac signal and reference DC signal；
The reference d.c. integration circuit, for obtaining the reference DC signal from the reference electric signal, and will be right
The integral result of the reference DC signal is exported to the MCU；
Wherein, the integral result of the reference DC signal is the testing result of the ambient light.
5. AFC system according to claim 1, it is characterised in that the measurement d.c. integration circuit, the microprocessor
MCU is integrated in the stepper motor on the printing board PCB of photoproduction electric signal processing circuit；
The measurement photodetector unit is integrated on Photoelectric Detection chip with the PCB.
6. AFC system according to claim 5, it is characterised in that also include polyvinylchloride framework；
The light collecting element is by the PVC framework above the Photoelectric Detection chip.
7. one kind focuses on AFC method automatically, it is characterised in that comprise the steps of：
When LED is opened, the optical signal of reception is focused at measurement photodetector unit by AFC system built-in light collecting element
On；Wherein, the flashlight that the optical signal is sent comprising LED；
The optical signal for receiving is converted to measurement electric signal by the measurement photodetector unit；Wherein, the measurement electricity
Signal is comprising measurement ac signal and measurement DC signal；
The measurement DC signal will be to the measurement is obtained from the measurement electric signal by measurement d.c. integration circuit
The integral result of DC signal is exported to Micro-processor MCV；
By the MCU according to the integral result of the measurement DC signal for receiving, the light harvesting is controlled by stepper motor
Element is moved back and forth in the distance of swimming, until the light collecting element is parked in the integral result for measuring DC signal being
The corresponding position of maximum；
Wherein, the scope of the distance of swimming be from the light collecting element away from described measurement photodetector unit minimum position to most
Big position.
8. AFC method according to claim 7, it is characterised in that the default initial position of the light collecting element is remote
Minimum position or maximum position from the measurement photodetector unit.
9. AFC method according to claim 7, it is characterised in that will connect in the light collecting element built-in by AFC system
Before the optical signal of receipts is focused at the step in measurement photodetector unit, comprise the steps of：
Before the LED is opened, ambient light is detected by the AFC system, and records the testing result of the ambient light；
By the MCU according to the integral result of the measurement DC signal for receiving, the light harvesting is controlled by stepper motor
Element is moved back and forth in the distance of swimming, until the light collecting element is parked in the integral result for measuring DC signal being
The step of maximum corresponding position is：
The testing result of the ambient light is deducted by the AFC system from the testing result of the optical signal, obtains the letter
The testing result of number light, and the testing result according to the flashlight, control the light collecting element to exist by the stepper motor
Moved back and forth in the distance of swimming, until it is the corresponding position of maximum that the light collecting element is parked in the testing result of the flashlight
Put, wherein, the optical signal is comprising the ambient light and the flashlight.
10. AFC method according to claim 9, it is characterised in that the AFC system also includes reference Photoelectric Detection list
Unit and reference d.c. integration circuit；
Before the LED is opened, ambient light is detected by the AFC system, and records the step of the testing result of the ambient light
In rapid, comprising following sub-step：
The ambient light is converted to reference electric signal by the reference photodetector unit；Wherein, the reference electric signal bag
Ac signal containing reference and reference DC signal；
The reference DC signal is obtained from the reference electric signal by the reference d.c. integration circuit, and will be to described
The integral result of reference DC signal is exported to the MCU；
Wherein, the integral result of the reference DC signal is the testing result of the ambient light.
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| CN201410784698.0A CN104570275B (en) | 2014-12-16 | 2014-12-16 | A kind of autofocus system and method |
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| CN201410784698.0A CN104570275B (en) | 2014-12-16 | 2014-12-16 | A kind of autofocus system and method |
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| JP3338322B2 (en) * | 1997-02-25 | 2002-10-28 | 三洋電機株式会社 | Auto focus camera |
| JP4415425B2 (en) * | 1999-06-25 | 2010-02-17 | 株式会社ニコン | Optical equipment with auto focus / manual focus switching |
| JP2004093776A (en) * | 2002-08-30 | 2004-03-25 | Nikon Corp | Camera |
| JP4040406B2 (en) * | 2002-09-20 | 2008-01-30 | キヤノン株式会社 | Camera system, camera and lens device |
| KR20070040547A (en) * | 2005-10-12 | 2007-04-17 | 엘지전자 주식회사 | Method and apparatus for auto-focusing for camera |
| KR20090123636A (en) * | 2008-05-28 | 2009-12-02 | (주)비씨엔이글로발 | Wireless camera system |
| TWI406025B (en) * | 2010-11-25 | 2013-08-21 | Ind Tech Res Inst | Automatic focusing apparatus and method |
| CN202268957U (en) * | 2011-11-04 | 2012-06-06 | 王兴国 | Automatic focus control system for electric lens of digital video camera |
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Effective date of registration: 20191101 Address after: 201702 B, 4 floor, 2 building, 888 Xuhua Road, Xujing Town, Qingpu District, Shanghai. Patentee after: Hezun Health Technology (Shanghai) Co., Ltd. Address before: Taicang City, Suzhou City, Jiangsu Province, and 215400 Metro Jianxiong Road No. 20 Patentee before: Granary micro-rump electron Science and Technology Ltd. |