CN100543574C - The automatic focusing mechanism of automatic focusing method and Electrofax - Google Patents
The automatic focusing mechanism of automatic focusing method and Electrofax Download PDFInfo
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- CN100543574C CN100543574C CNB2004100864999A CN200410086499A CN100543574C CN 100543574 C CN100543574 C CN 100543574C CN B2004100864999 A CNB2004100864999 A CN B2004100864999A CN 200410086499 A CN200410086499 A CN 200410086499A CN 100543574 C CN100543574 C CN 100543574C
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Abstract
The invention provides the automatic focusing mechanism of a kind of automatic focusing method and Electrofax.This automatic focusing method is by with respect to the progressively comparison to the left or to the right of the center position of zoom lens, thereby finds out the maximum evaluation of estimate of desiring photographic images, i.e. high fdrequency component, and should the maximum evaluation of estimate be the evaluation of estimate of best focal point.Automatic focusing method provided by the invention moves with on-fixed step number CD-ROM drive motor, and need not repeatedly to come and go mobile motor.In addition, automatic focusing mechanism provided by the invention need not to carry out flyback action before focusing, thereby can shorten the focusing time.
Description
Technical field
The present invention relates to a kind of camera automatic focusing method, particularly relate to a kind of picture appraisal value prediction focal position that utilizes to shorten the focusing time method.
Background technology
For control camera zoom lens is focused automatically, existing focusing method is to utilize the basis for estimation of focusing automatically according to the evaluation of estimate conduct that picture signal produced, this need repeatedly move back and forth lens set and carry out that omnidistance coarse scan is taken aim at and follow-up close scanning supervisor, so that obtain the evaluation of estimate of each focusing position.Then, analyze, contrast according to focal modes again, find out focal position, mobile then lens set is to focal position.Owing to need repeatedly CD-ROM drive motor to move lens set, quite expend time in, and can increase the rate of wear of motor and transmission component.If this focusedimage is not the image that desire is taken, then need to repeat the focusing action, also can waste the focusing time.
Aforementioned evaluation of estimate is to make image pass through bandpass filter or Hi-pass filter to produce high fdrequency component (High Frequency Component HFC) obtains.When focus lens is moved, on the evaluation of estimate curve, there is maximum relatively (or minimum) evaluation of estimate, then focusing position that should evaluation of estimate is focusing.Prior art because the appraisal curve slope is big inadequately, makes to be difficult for the influence that evaluation of estimate is changed by external factor easily obtaining this maximum relatively evaluation of estimate, thereby can't to obtain best focusing position when obtaining evaluation of estimate and corresponding with it focus.In the zoom lens of reality, for different zoom ratios (zoom ratio), its evaluation of estimate distributional difference is very big.
Look in the distance or during wide-angle,, then have following point to produce when the position of zoom lens becomes from normal place if the window size in focusing zone immobilizes.One, when the position of zoom lens when standard is pushed to look in the distance, its evaluation of estimate will form a very narrow peak value shown in Figure 1A and 1B.Its two, when the position of zoom lens when standard is pushed wide-angle to, its evaluation of estimate will be shown in Fig. 1 C and 1D, form one very smooth and almost do not have the curve of peak value.
Currently used a kind of solution is the design rectangular window, to construct a special hardware configuration, and No. 172155 patent of TaiWan, China for example.In this patent, under the changeless situation of window size, obtain the high fdrequency component of image with many groups high frequency filter, utilize different high frequency filters, realize the purpose of focusing by the fixing slope of appraisal curve.
In addition, can also utilize two groups of focusing control loops, first group of control loop is urged to a maximum value position (may not be relative maximum) earlier, the position that then cooperates zoom by second group of control loop, seek the position of relative maximum with less spacing, for example the U.S. the 4th, 903, No. 134 disclosed technology of patent.Perhaps in-service evaluation value rate of curve is switched several groups of different wave filters back and forth, cooperates the judgement of brightness, and to switch two groups of fixing windows, for example the U.S. the 5th, 235, No. 428 disclosed technology of patent.In this patent, preestablish the window of two different sizes, it must dispose the high fdrequency component that a plurality of high frequency filters are obtained image, and aspect focusing, utilizes the reduction of evaluation of estimate increment rate to switch different high frequency filters, thereby realizes the focusing purpose.
Fig. 2 is the curve synoptic diagram of mountain style focusing method." mountain style focusing method " utilizes the progressive method into of forcing to find the peak value of curve, it utilizes on the different focal high fdrequency component accumulated value (being evaluation of estimate) on same the image, just can obtain curve as described in Figure 1, and evaluation of estimate largest peaks place on the curve is correct focus point.That focuses is whether clear, depends on the peak that whether can find on the curve.In the process of seeking,, will make that the time of seeking peak value is elongated, even can't find peak value if the situation of aforementioned extremely narrow or extremely smooth peak value takes place.
Below sketch mountain style focusing method.As shown in Figure 2, transverse axis is a focusing position, and the longitudinal axis is the high fdrequency component of image.Suppose that the focusing reference position is the A point, drive focusing motor to B point (suppose motor moving direction for forward) at this moment.If the high fdrequency component that B is ordered, then forward promotes motor greater than the A point again to the C point.If the high fdrequency component that C is ordered then forward promotes motor to the D point again greater than the B point.According to shown in Figure 2, this moment the D high fdrequency component of order less than the C point, be illustrated in image that the focusing of D point obtains than C point fuzziness, thereby the reverse promotion focusing motor of needs arrives the E point.If the E high fdrequency component of ordering is greater than the C point, then another mistake to CD-ROM drive motor to the F point.If the F high fdrequency component of ordering is less than the E point, then forward CD-ROM drive motor to the G point.So CD-ROM drive motor is also slowly approached high fdrequency component to find peak relative on the curve, promptly maximum high fdrequency component repeatedly.In the process of approaching,,, otherwise be difficult to find its peak unless the step number that motor moves is very little if precipitous or smooth as the curve image pattern 1B of Fig. 2 or Fig. 1 D.In addition, if the step number that motor moves diminishes, then the focusing time can increase relatively.
In addition, another kind of focusing method is called " going on foot search method greatly ", and promptly CD-ROM drive motor is a unit zoom lens motionless zoom lens with per 7 steps, and obtains corresponding high fdrequency component in each unit distance.After the high fdrequency component in obtaining all unit distances, carry out the single step search at the unit distance that wherein comprises maximum high fdrequency component again, to find out actual maximum high fdrequency component.The shortcoming of this method is could search according to a segment distance wherein after needing to put in order segment distance and covering again, thereby quite loses time.
Compare with big step search method and other method of focusing with hardware mode, mountain style focusing method is comparatively simple, and can realize the purpose of focusing fast.Yet existing mountain style focusing method must come and go CD-ROM drive motor to obtain the focal position, still has the space of improvement on the focusing time.Therefore, the invention provides a kind of automatic focusing method, with the further shortening focusing time.
Summary of the invention
In view of this, the object of the present invention is to provide a kind of automatic focusing method, in order to shorten the focusing time.
To achieve these goals, the invention provides a kind of automatic focusing method, be applicable to the zoom lens of Electrofax, wherein, picture signal is obtained by described zoom lens, and described zoom lens is characterized in that by a motor driven described method comprises the following steps: a) to confirm the reference position of described zoom lens; B) judge the relative position of described zoom lens and focusing orbit centre point, with drive described motor to first or second direction move; C) read the evaluation of estimate corresponding, and make the first evaluation variate-value equal described evaluation of estimate with described picture signal; D) drive described motor and move K unit distance to first direction, wherein the value of K is greater than 1; E) read the next evaluation of estimate corresponding, and make the second evaluation variate-value equal described evaluation of estimate with described picture signal; F) judge that whether described second estimate variate-value less than the described first evaluation variate-value; G), then make the described first evaluation variate-value equal described second and estimate variate-value, execution in step d then if the described second evaluation variate-value is estimated variate-value more than or equal to described first; H) if the described second evaluation variate-value is estimated variate-value less than described first, drive described motor and move a unit distance to second direction; I) read the evaluation of estimate corresponding, and make the described first evaluation variate-value equal described evaluation of estimate with described picture signal; J) drive described motor and move a unit distance to described second direction; K) read the next evaluation of estimate corresponding, and make the described second evaluation variate-value equal described evaluation of estimate with described picture signal; 1) judges that whether described second estimate variate-value less than the described first evaluation variate-value; M), then make the described first evaluation variate-value equal described second and estimate variate-value, execution in step j then if the described second evaluation variate-value is estimated variate-value more than or equal to described first; N) if the described second evaluation variate-value is estimated variate-value less than described first, drive described motor and move a unit distance to described first direction, wherein, the evaluation of estimate that is read on the current position of described motor is maximum evaluation of estimate.
And described step f also comprises the following steps: f1) judge that whether described second estimate variate-value less than the described first evaluation variate-value, and whether described motor arrives one of them border of described focusing track; F2) if the described second evaluation variate-value is estimated variate-value more than or equal to described first, and the described border of described motor no show, then execution in step e; F3) if described second estimate variate-value and estimate variate-value more than or equal to described first, and described motor arrived described border, represents that then the evaluation of estimate that is read on the current position of described motor is maximum evaluation of estimate; F4) if the described second evaluation variate-value is estimated variate-value, then execution in step h less than described first.
Automatic focusing method of the present invention, step c comprises also by mathematical formulae and determines described K value that described mathematical formulae is:
Wherein, FR represents the frame rate of described picture signal, and SP represents the gait of march of described motor, and Floor represents the merchant through obtaining behind the division arithmetic.
Automatic focusing method of the present invention before reading described evaluation of estimate, needs to wait for two vertical synchronizing signal times earlier.
Automatic focusing method of the present invention in step h, drove described motor before described second direction moves, and removed described first and second and estimated variate-value.
Automatic focusing method of the present invention, described focus process are not carried out the operation of confirming lens location.
To achieve these goals, the present invention also provides a kind of automatic focusing mechanism of Electrofax, comprising: a zoom lens is used for obtaining sensor of picture signal, sense described picture signal by described zoom lens, and described picture signal is converted to Digital Image Data; A signal processing unit is coupled to described sensor, receives described Digital Image Data, and produces a luminance signal after treatment; A data processing unit is coupled to described signal processing unit, produces first and second evaluations of estimate of described picture signal successively according to described luminance signal; A motor is used for driving described zoom lens and moves to a focal position; And microcontroller, be coupled to described data processing unit and motor, judge the relative position of described zoom lens and focusing orbit centre point, driving described motor drives described zoom lens and continues to move to first direction with K unit distance, and obtain described first and second evaluations of estimate successively, when described second evaluation of estimate during less than described first evaluation of estimate, remove described first and second evaluations of estimate, driving described motor then drives described zoom lens and continues to move to second direction with a unit distance, and obtain described first and second evaluation of estimate successively, and when described second evaluation of estimate during less than described first evaluation of estimate, drive described motor and drive described zoom lens and continue to move a unit distance, make described zoom lens move to described focal position to described first direction.
Wherein, described microcontroller judges also whether whether described second evaluation of estimate arrive one of them border of described focusing track less than described first evaluation of estimate and described motor, if described second evaluation of estimate is more than or equal to described first evaluation of estimate, and the described border of described motor no show, then make described first evaluation of estimate equal described second evaluation of estimate, and drive described motor and move K unit distance, to read next evaluation of estimate to described first direction; If described second evaluation of estimate is more than or equal to described first evaluation of estimate, and described motor arrived described border, represents that then described zoom lens moves to described focal position; If described second evaluation of estimate is less than described first evaluation of estimate, then described microcontroller is removed described first and second evaluations of estimate, and drives described motor and move to described second direction.
Automatic focusing mechanism of the present invention, when described motor moves and described second evaluation of estimate during more than or equal to described first evaluation of estimate to described first direction, described microcontroller makes described first evaluation of estimate equal described second evaluation of estimate, drive described motor then and move K unit distance, to read next evaluation of estimate towards described first direction.
Automatic focusing mechanism of the present invention, when described motor moves and described second evaluation of estimate during more than or equal to described first evaluation of estimate to described second direction, described microcontroller makes described first evaluation of estimate equal described second evaluation of estimate, drive described motor then and move a unit distance, to read next evaluation of estimate to described second direction.
Automatic focusing mechanism of the present invention, described microcontroller are not carried out the operation of confirming lens location in carrying out described focus process.
Automatic focusing mechanism of the present invention, described microcontroller determines described K value by mathematical formulae, described mathematical formulae is:
Wherein, FR represents the frame rate of described picture signal, and SP represents the gait of march of described motor, and Floor represents the merchant through obtaining behind the division arithmetic.
Automatic focusing mechanism of the present invention before reading described first and second evaluations of estimate, needs to wait for two vertical synchronizing signal times earlier.
Automatic focusing mechanism of the present invention, described automatic focusing mechanism also comprise a motor driven chip, drive described motor according to the control signal from described microcontroller and drive described zoom lens, make described zoom lens move to described focal position.
Automatic focusing mechanism of the present invention, described automatic focusing mechanism also comprise a zoom lens sensor, and the current position signal of described zoom lens is returned to described microcontroller.
Automatic focusing mechanism of the present invention, the value of described K is greater than 1.
Compare with existing focusing method, automatic focusing method provided by the invention is not to move with fixing step number CD-ROM drive motor, and need not repeatedly to come and go mobile motor, needs round secondary can find best focusing position following of optimum.In addition, automatic focusing mechanism of the present invention need not to carry out flyback action earlier before focusing, thereby can shorten the focusing time.
Description of drawings
Figure 1A and Figure 1B are the evaluation of estimate curve of position when standard is pushed to look in the distance of zoom lens.
Fig. 1 C and Fig. 1 D are the evaluation of estimate curve of position when standard is pushed wide-angle to of zoom lens.
Fig. 2 is the curve synoptic diagram of mountain style focusing method.
Fig. 3 is the structural representation of embodiment of the invention automatic focusing mechanism.
Fig. 4 is the synoptic diagram that embodiment of the invention automatic focusing mechanism moves on the focusing track.
Fig. 5 A and Fig. 5 B are focus the automatically detailed step process flow diagrams of method of the embodiment of the invention.
Embodiment
For above and other objects of the present invention, feature and advantage are become apparent, hereinafter enumerate preferred embodiment, and described in detail in conjunction with the accompanying drawings.
The invention provides the automatic focusing mechanism of a kind of automatic focusing method and Electrofax.
Embodiments of the invention are found out the maximum evaluation of estimate (being high fdrequency component) of desiring photographic images by relative zoom lens central point (Center) progressively comparison to the left or to the right, and this maximum evaluation of estimate is the evaluation of estimate of best focal point.
In an embodiment of the present invention, the step number that moves of motor is determined by following formula:
Wherein, when K represents that zoom lens reads a frame of digital picture signal, the maximum step number that motor need move, Floor represents through the merchant behind the division arithmetic, FR (framerate) represents frame rate, be the quantity of the frame of per second shooting, the gait of march of SP (step period) expression motor, promptly motor whenever moves the time of the required cost that moves a step.Suppose that FR is that 33/ms (takes 33 frames for every millisecond, be 1/33 millisecond of every frame period), SP is 0.01ms/step (is motor whenever move to move a step need 0.01 millisecond), it is Floor[(1/33 that the above-mentioned formula of substitution can get the required mobile ultimate range of motor)/0.01], be K=3, hence one can see that, and motor desires to read a frame need move for three steps.In addition, motor is movably focused the central point of track for (Rightboundary+Leftboundary)/2, and wherein, Rightboundary represents the right margin of this focusing track, Leftboundary represent the to focus left margin of track.
In the present invention, it is not fixed value that motor moves step number, and it is mainly determined by the gait of march (SP) of frame rate (FR) with motor.
Fig. 3 is the structural representation of embodiment of the invention automatic focusing mechanism.Camera 300 comprises a Focusing module 310, sensor 320, signal processing unit 330, data processing unit 340, a microcontroller 350, and a zoom lens sensor 360.Focusing module 310 comprises a zoom lens 311, a motor 313, and a motor driven chip 315.
As shown in Figure 3, sensor 320 senses picture signal by zoom lens 311, and is converted to Digital Image Data, produces a luminance signal then after signal processing unit 330 is handled.Can obtain the focusing evaluation of estimate corresponding, promptly corresponding high fdrequency component after 340 pairs of these luminance signal computings of data processing unit with this view data with this picture signal.The size of this evaluation of estimate direction that decides motor 313 to move, and judge whether zoom lens 311 finishes focusing.Microcontroller 350 is control maincenters of camera 300, it according to data processing unit 340 calculate evaluation of estimate and the current position signal of the zoom lens 311 of zoom lens sensor 360 passback, export one and control signal to motor driven chip 315, thus the driving direction and the mobile step number of control motor 313.The driving direction of said motor 313 and mobile step number can influence the speed and the degree of accuracy of focusing.
After the focusing program begins, the picture appraisal value that microcontroller 350 reading of data processing units 340 are produced, and it is made as V1.Then move three steps (K=3 at this moment) to a direction (with respect to the left of central point or right-hand) according to aforementioned formula and set information CD-ROM drive motor 313.Then, wait for that two vertical synchronizing signal (VerticalSynchronization Signal) times (whenever read a frame, it comprises the exposure result of two vertical synchronizing signals) after, read next evaluation of estimate, and it is made as V2 (waiting for that two vertical synchronizing signal times are the values that read V1 and V2 in order to ensure stablizing).Next, microcontroller 350 judges that whether V2 is greater than V1 (being designated as " condition A ").If V2 less than V1, is waiting for two vertical synchronizing signals after the time, microcontroller 350 CD-ROM drive motor 313 are to moving in the other direction.Before moving as yet, the value of microcontroller 350 first replacement V1 and V2, CD-ROM drive motor 313 is moved and is moved a step then, then reads evaluation of estimate, and it is made as V1, and CD-ROM drive motor 313 moves a step and reads next evaluation of estimate towards equidirectional moving again then, and it is made as V2.Next, microcontroller 350 judges that whether V2 is less than V1.If V2 more than or equal to V1, then makes the value of V1 equal the value of V2, wait for that then two vertical synchronizing signals read next evaluation of estimate again to continue compare operation after the time.If V2 is less than V1, then CD-ROM drive motor 313 moves a step toward moving in the other direction again, and then this position is the position of best focal point.
At condition A place, if V2 greater than V1, then makes the value of V1 equal the value of V2, CD-ROM drive motor 313 moved for three steps to same direction (direction that motor moves when promptly obtaining V1 and V2) then, and waiting for that two vertical synchronizing signals read next evaluation of estimate after the time, and it is being made as V2.Then, microcontroller 350 judges whether whether V2 moved to the border (being designated as " condition B ") of focusing track 370 (as shown in Figure 4) less than V1 and motor 313.If V2 is more than or equal to V1 and motor 313 no show borders, then CD-ROM drive motor 313 continues to move for three steps in the same direction, and waits for that two vertical synchronizing signals read next evaluation of estimate after the time.If V2 has arrived the border more than or equal to V1 and motor 313, then best focal point is found in expression, finishes the focusing program.
At condition B place, less than V1, no matter then whether motor 313 has arrived the border, microcontroller 350 is waiting for that two vertical synchronizing signal time rear drive motors 313 are to moving in the other direction as if V2.Before not moving as yet, the value of microcontroller 350 first replacement V1 and V2, CD-ROM drive motor 313 is moved and is moved a step then, and waiting for that two vertical synchronizing signals read evaluation of estimate after the time, and it is made as V1, CD-ROM drive motor 313 moves a step towards equidirectional moving again then, and waits for that two vertical synchronizing signals read next evaluation of estimate after the time, and it is made as V2.Next, microcontroller 350 judges that whether V2 is less than V1.If V2 more than or equal to V1, then makes the value of V1 equal the value of V2, waiting for that two vertical synchronizing signals read next evaluation of estimate to continue relatively after the time then.If V2 is less than V1, then microcontroller 350 CD-ROM drive motor 313 are moved to opposite direction and are moved a step, and this position is the position of best focal point.
Fig. 5 A and Fig. 5 B are focus the automatically detailed step process flow diagrams of method of the embodiment of the invention.
In step S1, confirm the zoom lens current location.
In step S2, obtain the focusing information and first evaluation of estimate.Whenever move the required Time Calculation that moves a step according to aforementioned formula, frame rate and motor and go out the required mobile maximum step number of motor, obtain the center position of motor and focusing track (as shown in Figure 4), read current evaluation of estimate and it is made as V1.
In step S3, judge that the zoom lens reference position is whether greater than center position (promptly whether in center position right-hand).If, execution in step S4 then, otherwise execution in step S31.This determining step is in order to make motor drive camera lens to the action of focusing of central point direction.
In step S31, as if the left of zoom lens reference position in center position, then CD-ROM drive motor moves to right-hand.
In step S4, if zoom lens reference position right-hand in center position, then CD-ROM drive motor moves to left.
In step S5, CD-ROM drive motor moved for three steps (supposing K=3, down together) and waits for two vertical synchronizing signals after the time, reads evaluation of estimate at that time, and it is made as V2.
In step S6, judge that whether V2 is more than or equal to V1.If, execution in step S7 then, otherwise skip to step S9, CD-ROM drive motor is to moving in the other direction.Before moving as yet, the value of microcontroller 350 first replacement V1 and V2, the value of removing V1 and V2.
In step S7, if V2 greater than V1, then makes the value of V1 equal the value of V2, CD-ROM drive motor moved for three steps with same direction then, and was waiting for that two vertical synchronizing signals read next evaluation of estimate after the time, and it is made as V2.
In step S8, judge whether whether V2 moved to the border of focusing track (as shown in Figure 4) less than V1 and motor.(solid line represents that evaluation of estimate judges if V2 does not move to the border more than or equal to V1 and motor, dotted line is represented the border judgement), then skip to step S7, CD-ROM drive motor continues to move for three steps in the same direction, and waits for that two vertical synchronizing signals read next evaluation of estimate after the time.If V2 has arrived the border more than or equal to V1 and motor, then best focal point is found in expression, so finish the focusing program.If V2 is less than V1, execution in step S9 then.
In step S9,,, move a step waiting for that two vertical synchronizing signal time rear drive motors 313 move to opposite direction then no matter whether motor has arrived the border if V2 is less than V1.Before moving as yet, the value of first replacement V1 and V2 is promptly removed the value of V1 and V2.
In step S10, waiting for that two vertical synchronizing signals after the time, read evaluation of estimate at that time, and it is made as V1.
In step S11, CD-ROM drive motor moves a step towards equidirectional moving again, and waits for that two vertical synchronizing signals read next evaluation of estimate after the time, and it is made as V2.
In step S12, judge that whether V2 is less than V1.
In step S13, if V2 greater than V1, then makes the value of V1 equal the value of V2, skip to step S11 then, wait for that two vertical synchronizing signals read next evaluation of estimate to continue relatively after the time.
In step S14, less than V1, then CD-ROM drive motor moves a step toward moving in the other direction again as if V2, and this position is the position of best focal point.
Compare with existing focusing method, the embodiment of the invention method of focusing automatically is not to move with fixing step number CD-ROM drive motor, and need not repeatedly to come and go mobile motor, needs round secondary can find best focusing position following of optimum.In addition, embodiment of the invention automatic focusing mechanism need not to carry out flyback action earlier before focusing, thereby can shorten the focusing time.
Though the present invention by the preferred embodiment explanation as above, this preferred embodiment is not in order to limit the present invention.Those skilled in the art without departing from the spirit and scope of the present invention, should have the ability this preferred embodiment is made various changes and replenished, so protection scope of the present invention is as the criterion with the scope of claims.
Being simply described as follows of symbol in the accompanying drawing:
300: camera 330: signal processing unit
310: Focusing module 340: data processing unit
311: zoom lens 350: microcontroller
313: motor 360: the zoom lens sensor
315: motor drives chip 370: the focusing track
320: sensor
Claims (14)
1, a kind of automatic focusing method is applicable to the zoom lens of Electrofax, and wherein, picture signal is obtained by described zoom lens, and described zoom lens is characterized in that by a motor driven described method comprises the following steps:
A) reference position of the described zoom lens of affirmation;
B) judge the relative position of described zoom lens and focusing orbit centre point, with drive described motor to first or second direction move;
C) read the evaluation of estimate corresponding, and make the first evaluation variate-value equal described evaluation of estimate with described picture signal;
D) drive described motor and move K unit distance to first direction, wherein the value of K is greater than 1;
E) read the next evaluation of estimate corresponding, and make the second evaluation variate-value equal described evaluation of estimate with described picture signal;
F) judge that whether described second estimate variate-value less than the described first evaluation variate-value; It also comprises the following steps:
F1) judge that whether described second estimate variate-value less than the described first evaluation variate-value, and whether described motor arrives one of them border of described focusing track;
F2) if the described second evaluation variate-value is estimated variate-value more than or equal to described first, and the described border of described motor no show, then execution in step e;
F3) if described second estimate variate-value and estimate variate-value more than or equal to described first, and described motor arrived described border, represents that then the evaluation of estimate that is read on the current position of described motor is maximum evaluation of estimate; And
F4) if the described second evaluation variate-value is estimated variate-value, then execution in step h less than described first;
G), then make the described first evaluation variate-value equal described second and estimate variate-value, execution in step d then if the described second evaluation variate-value is estimated variate-value more than or equal to described first;
H) if the described second evaluation variate-value is estimated variate-value less than described first, drive described motor and move a unit distance to second direction;
I) read the evaluation of estimate corresponding, and make the described first evaluation variate-value equal described evaluation of estimate with described picture signal;
J) drive described motor and move a unit distance to described second direction;
K) read the next evaluation of estimate corresponding, and make the described second evaluation variate-value equal described evaluation of estimate with described picture signal;
L) judge that whether described second estimate variate-value less than the described first evaluation variate-value;
M), then make the described first evaluation variate-value equal described second and estimate variate-value, execution in step j then if the described second evaluation variate-value is estimated variate-value more than or equal to described first; And
N) if the described second evaluation variate-value is estimated variate-value less than described first, drive described motor and move a unit distance to described first direction, wherein, the evaluation of estimate that is read on the current position of described motor is maximum evaluation of estimate.
2, automatic focusing method according to claim 1 is characterized in that step c also comprises by mathematical formulae to determine described K value, and described mathematical formulae is:
Wherein, FR represents the frame rate of described picture signal, and SP represents the gait of march of described motor, and Floor represents the merchant through obtaining behind the division arithmetic.
3, automatic focusing method according to claim 1 is characterized in that before reading described evaluation of estimate, needed to wait for two vertical synchronizing signal times earlier.
4, automatic focusing method according to claim 1 is characterized in that in step h, drives described motor before described second direction moves, and removes described first and second and estimates variate-value.
5, automatic focusing method according to claim 1 is characterized in that described focus process do not carry out the operation of confirming lens location.
6, a kind of automatic focusing mechanism of Electrofax is characterized in that comprising:
A zoom lens is used for obtaining picture signal;
A sensor senses described picture signal by described zoom lens, and described picture signal is converted to Digital Image Data;
A signal processing unit is coupled to described sensor, receives described Digital Image Data, and produces a luminance signal after treatment;
A data processing unit is coupled to described signal processing unit, produces first and second evaluations of estimate of described picture signal successively according to described luminance signal;
A motor is used for driving described zoom lens and moves to a focal position; And
A microcontroller, be coupled to described data processing unit and motor, judge the relative position of described zoom lens and focusing orbit centre point, driving described motor drives described zoom lens and continues to move to first direction with K unit distance, and obtain described first and second evaluations of estimate successively, when described second evaluation of estimate during less than described first evaluation of estimate, remove described first and second evaluations of estimate, driving described motor then drives described zoom lens and continues to move to second direction with a unit distance, and obtain described first and second evaluation of estimate successively, and when described second evaluation of estimate during less than described first evaluation of estimate, drive described motor and drive described zoom lens and continue to move a unit distance, make described zoom lens move to described focal position to described first direction;
Wherein, described microcontroller judges also whether whether described second evaluation of estimate arrive one of them border of described focusing track less than described first evaluation of estimate and described motor, if described second evaluation of estimate is more than or equal to described first evaluation of estimate, and the described border of described motor no show, then make described first evaluation of estimate equal described second evaluation of estimate, and drive described motor and move K unit distance to described first direction, to read next evaluation of estimate, if described second evaluation of estimate is more than or equal to described first evaluation of estimate, and described motor has arrived described border, represent that then described zoom lens moves to described focal position, if described second evaluation of estimate is less than described first evaluation of estimate, then described microcontroller is removed described first and second evaluations of estimate, and drives described motor and move to described second direction.
7, automatic focusing mechanism according to claim 6, it is characterized in that moving and described second evaluation of estimate during to described first direction more than or equal to described first evaluation of estimate when described motor, described microcontroller makes described first evaluation of estimate equal described second evaluation of estimate, drive described motor then and move K unit distance, to read next evaluation of estimate towards described first direction.
8, automatic focusing mechanism according to claim 7, it is characterized in that moving and described second evaluation of estimate during to described second direction more than or equal to described first evaluation of estimate when described motor, described microcontroller makes described first evaluation of estimate equal described second evaluation of estimate, drive described motor then and move a unit distance, to read next evaluation of estimate to described second direction.
9, automatic focusing mechanism according to claim 6 is characterized in that described microcontroller do not carry out the operation of confirming lens location in carrying out described focus process.
10, automatic focusing mechanism according to claim 6 is characterized in that described microcontroller determines described K value by mathematical formulae, and described mathematical formulae is:
Wherein, FR represents the frame rate of described picture signal, and SP represents the gait of march of described motor, and Floor represents the merchant through obtaining behind the division arithmetic.
11, automatic focusing mechanism according to claim 6 is characterized in that before reading described first and second evaluations of estimate, needed to wait for two vertical synchronizing signal times earlier.
12, automatic focusing mechanism according to claim 6, it is characterized in that described automatic focusing mechanism also comprises a motor driven chip, drive described motor according to control signal and drive described zoom lens, make described zoom lens move to described focal position from described microcontroller.
13, automatic focusing mechanism according to claim 6 is characterized in that described automatic focusing mechanism also comprises a zoom lens sensor, and the current position signal of described zoom lens is returned to described microcontroller.
14, automatic focusing mechanism according to claim 6, the value that it is characterized in that described K is greater than 1.
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| CN100592189C (en) * | 2006-06-13 | 2010-02-24 | 鸿富锦精密工业（深圳）有限公司 | Focusing method for image pick-up device |
| CN100458544C (en) * | 2006-10-10 | 2009-02-04 | 北京中星微电子有限公司 | Automatic focusing method for digital image pickup device |
| CN101191980B (en) * | 2006-11-27 | 2010-09-01 | 亚洲光学股份有限公司 | Automatic focusing method |
| CN101571660B (en) * | 2008-04-28 | 2011-01-05 | 鸿富锦精密工业（深圳）有限公司 | Digital camera and automatic focusing method thereof |
| CN102087459B (en) * | 2009-12-04 | 2013-07-03 | 豪威科技有限公司 | Automatic focusing method |
| US8648959B2 (en) * | 2010-11-11 | 2014-02-11 | DigitalOptics Corporation Europe Limited | Rapid auto-focus using classifier chains, MEMS and/or multiple object focusing |
| CN105959533B (en) * | 2016-04-27 | 2018-11-30 | 维沃移动通信有限公司 | A kind of focusing method and mobile terminal |
| CN105824098A (en) * | 2016-05-04 | 2016-08-03 | 广东欧珀移动通信有限公司 | Focusing control method and device, imaging control method and device, and electronic device |
| CN107079102B (en) | 2016-09-26 | 2019-02-22 | 深圳市大疆创新科技有限公司 | Focusing method, photographic device and unmanned plane |
| CN106791434B (en) * | 2017-01-18 | 2019-12-13 | 捷开通讯(深圳)有限公司 | Device and method for assisting in picture definition by AF focusing |
| CN109274885B (en) * | 2018-09-11 | 2021-03-26 | 广东智媒云图科技股份有限公司 | Fine adjustment method for photographing |
| CN109873948B (en) * | 2019-01-30 | 2020-06-26 | 中国地质大学（武汉） | Intelligent automatic focusing method and device for optical microscope and storage device |
| CN110031960B (en) * | 2019-05-30 | 2021-06-22 | 上海商汤智能科技有限公司 | Automatic adjustment method and device |
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