JP2920652B2 - Automatic focus adjustment device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detection device having a camera predictive drive device.

[Conventional technology]

The conventional automatic focus detection device determines whether or not the subject is moving based on the past several times of defocus amount from the focus detection means. As a result, if the subject is moving, the past several times of defocusing is performed. The movement of the subject is predicted based on the amount, and the defocus amount of the focus detection means is corrected so as to follow the movement of the subject. This makes it possible to keep focusing on a moving subject, and such a technique is disclosed in
It is already known such as -148218.

[Problems to be solved by the invention]

In the prior art as described above, since the lens is driven based on the amount of defocus of the past several times, for example, a person crosses in front of the main subject, or the main subject is only momentarily deviated from the focus detection frame and is erroneous. In the case of a subject that detects the amount of defocus and drives the lens incorrectly or that passes through the side of the photographer, the lens driving direction changes suddenly, causing overrun etc. and accurate tracking can be performed There was no problem.

In view of the above, an object of the present invention is to provide a focus detection device having a prediction drive device that detects an erroneous defocus amount or that does not cause erroneous lens drive such as overrun even when the drive direction changes suddenly. I do.

[Means for solving the problem]

In order to solve the above problems, the present invention provides a tracking unit that predicts a movement of a subject based on a result of a focus detection signal of a focus detection unit in the past several times and generates a tracking signal related to a predicted movement amount; An automatic focus detection device comprising: a lens driving unit that drives the photographing lens based on a tracking signal of the unit; and a movement trajectory of the subject based on information on a movement of the subject and a focus detection signal of the focus detection unit. Trajectory determination means for determining a trajectory function; prediction means for predicting movement of a subject based on the trajectory function determined by the trajectory determination means to generate a predicted movement signal; latest focus detection signal of the focus detection means Departure determining means for determining whether or not deviates from the predicted movement signal generated by the predicting means; and Prediction control means for calculating a lens drive amount based on a predicted movement signal of the prediction means, and calculating a lens drive amount based on a tracking signal of the tracking means when it is not determined that the deviation is detected. Things.

[Operation] In the present invention, the tracking means predicts the movement of the subject based on the results of the focus detection several times in the past to generate a tracking signal relating to the predicted movement amount, and the prediction means provides information relating to the movement of the subject. From the trajectory function representing the trajectory of the subject determined based on the focus detection signal and the focus detection signal, a predicted movement signal that predicts the movement of the subject is generated. When the lens is driven, any of the tracking signal and the predicted movement signal is used. Whether to use or not is determined based on the result of the deviation determination means.

As a result, in the present invention, it is possible to drive the photographing lens based on the signal that always best follows the movement of the main subject, and to predict the future driving of the photographing lens from the trajectory function. Even when the driving direction is reversed, overrun can be prevented beforehand.

〔Example〕

 -First Embodiment- A first embodiment will be described with reference to FIGS.

FIG. 1 is a main configuration diagram of the present invention, and FIG. 2 is a diagram showing the relationship between a subject and a camera when photographing a subject crossing at a constant speed.

The focus detecting means 2 in FIG. 1 detects a defocus amount Dfn indicating a focus adjustment state (distance to a focal point of the photographing lens) of the photographing lens at time tn.

The tracking means 3 determines whether the subject is moving based on the defocus indicating the focus adjustment state of the focus detection means 2 in the past several times, and if the subject is moving, the detected defocus amount The defocus amount P _n (the amount by which the image plane has moved from the previous focus detection to the current focus detection, hereinafter referred to as a predicted defocus amount) for the movement of the subject that cannot catch up is P _n = Df _n + (previous defocus amount) -Df _n1
Is calculated as Further, another method of calculating the predicted defocus amount may be performed according to the method disclosed in Japanese Patent Application Laid-Open No. 63-148218 by the present applicant.

The object trajectory parameter setting means 20 presets trajectory parameters including the object speed V, the length d of a leg perpendicular to the trajectory, and the focal length f of the photographing lens as shown in FIG. It is selected and set from a plurality of trajectory parameters by an operation. The trajectory parameter is, for example, a representative value determined by the type of the subject (for sports photography, for automobile racing, etc.).

The trajectory determination unit 10 receives the defocus amount signal from the focus detection unit 2 and the parameter signal from the subject trajectory parameter setting unit 20 and outputs a signal indicating the subject movement trajectory to the prediction unit 11 based on both signals.

The prediction means 11 receives the movement trajectory signal from the trajectory determination means 10 and the trajectory parameter signal from the subject trajectory parameter setting means 20, and calculates a prediction signal that predicts the movement trajectory of the subject based on the two signals. It outputs to the prediction control means 13.

The departure determining unit 12 compares the signal regarding the defocus amount sequentially output from the focus detection unit 2 with the prediction signal output from the prediction unit 11, and determines that the two signals do not deviate from each other within a predetermined allowable range. A signal is output, and if they do not match, a deviation signal is output.

The prediction control unit 13 drives the lens driving unit 4 based on the prediction signal from the prediction unit 11 when the deviation signal from the deviation determination unit 12 is output, and predicts the tracking unit 3 when the non-deviation signal is output. The lens driving means 4 is driven based on the defocus amount signal.

Next, a process for normalizing the movement trajectory signal of the subject A generated by the trajectory determination means 10 will be described with reference to FIGS.

When photographing a subject A moving at a constant speed as shown in FIG. 2, three parameters of a subject speed V, a length d of a leg perpendicular to a locus, and a focal length f of a lens (hereinafter, referred to as locus parameters). ) Can determine only one trajectory.

However, when the object speed is different, the object shows a locus as shown in FIG. Further, when the length d of the foot perpendicular to the locus and the focal length f of the lens are different, the subject shows the locus as shown in FIGS. 3B and 3C, respectively. 3A to 3C, the horizontal axis represents time t, and the vertical axis represents the amount of lens extension from infinity.

As can be seen from FIGS. 3A to 3C, the movement trajectory of the subject A becomes a trajectory of many patterns due to a change in the trajectory parameter. It is impossible to store all these trajectory parameters in the subject trajectory parameter setting means 20 or to store the trajectory of the subject based on the trajectory parameters in the trajectory determination means 10. Therefore, the image plane moving speed is used to normalize the moving locus.

From FIG. 2, the photographing distance a is as shown in equation (1). However, it is assumed that the origin of time t is closest to the camera (when a = d).

a = ((Vt) ² + d ² ) ^1/2 (1) where V: subject speed d: length of a leg perpendicular to the trajectory in FIG. 2 Further, from the Newton's formula for the lens, (f << The following equation (2) is obtained as d).

ax = f ² (2) where x is the amount of extension f: focal length of the lens From the equations (1) and (2), the image plane moving speed u is given by the following equation (3).

Further modification yields the following equation (4).

Here, when the time t is converted by sign (t) = 1 (t ≧ 0) −1 (t <0) T = (V ^1/2 / f) t, the following equation (5) is obtained.
Get.

Generally, it is summarized as in the following equation (6).

However, T = (V ^1/2 / f) t = bt C = d ² / Vf ² Therefore, even if the trajectory parameters (subject speed V, length d, focal length f) are different, if C = constant, Trajectory determination means
The ten movement trajectory signals are signals along one curve determined by the equation (6).

FIG. 4 is a diagram showing C of equation (6) differently.
As described above, since the trajectory of the subject can be treated as the image formula (6), the prediction unit 11 sets C to be a constant even if the trajectory parameters are different, or C as a constant if it is within a predetermined range. It is possible to predict the trajectory of the subject from the expression (1).

Therefore, one of the most probable representative image formulas is stored in the trajectory determination means 10, and the image plane moving speed u is obtained from the results of the focus detection means 2 several times in the past, and the coefficient b of the formula (6) is obtained. Is determined, only one movement locus signal of the subject based on the coefficient b is determined.

The process in which the trajectory determination means 10 determines the movement trajectory signal will be described.

The subject trajectory parameter setting means 20 stores the constant C of the trajectory parameter of the subject which is most likely as described above.

The trajectory determination means 10 calculates the slope b of T = bt by inserting the image plane moving speed u obtained from the defocus amount signal sequentially output from the focus detection means 2 into the equation (6). Specifically, based on the defocus amount signal of the focus detection unit 2, the trajectory determination unit 10 calculates the predicted defocus amount _Pn at which the image plane has moved during the focus detection calculation and the time interval Δt thereof.
Calculated as following equation (7) the image plane movement velocity data u _n and a.

Then, successively by the formula (7), calculating a plurality of image plane movement velocity data u ₁ was, u _2, u _3, ‥‥ based on u _n, (6) T ₁ of FIG. 5 at each time from the equation , T ₂ , T ₃ , ΔT _n .

Then, the data sequence (t ₁ , T ₁ ) (t ₂ ,
T ₂ ) Find a linear function (T = bt) from ‥‥ (t _n , T _n ).

Generally, the slope b of the linear function (T = bt) may be obtained by the least square method or the like. Here, the number of data is required to be at least two since it is inserted into the linear expression, and it is desirable that the number is four or more in consideration of a measurement error or a curve when the actual trajectory deviates from the image type.

As described above, the trajectory determination means 10 obtains a movement trajectory signal representing the movement trajectory (image formula) of the subject, that is, a signal relating to the inclination b, based on the trajectory parameter signal from the subject trajectory parameter setting means 20, ie, the signal relating to the constant C. I have.

Once the slope b is obtained, the slope b
May be used, or the slope b may be obtained sequentially. Here, it is generally inconvenient for the time t to take the time of closest approach as the origin, so it is better to use the elapsed time t 'from a certain time. In this case, the time to pass through the closest point is t _o
When the t = t '= t _o. Therefore, the following equation (8) may be used as the obtained primary equation.

_{T = bt'-bt o = bt'} -α ...... (8) In this case, the locus determining means 10 would determine the slope b and Sehhen alpha as moving track signal.

If the slope b and the tangent α are determined by the trajectory determining means 10,
Since only one movement locus of the object is determined, it is possible to predict the speed in the future.

Next, the prediction unit 11 calculates a prediction signal by the following equation predicted image plane movement velocity u _n 'from the calculated slope b and Sehhen α and the time t _n in the trajectory determination unit 10 (9).

The predicted signal is a predicted image plane moving speed calculated by the equation (9).
u _n 'may be a, also predicted image plane movement velocity u _n' may be predicted defocus amount calculated on the basis of a signal associated with such predictions defocus amount.

Next, a signal based on the latest defocus amount of the focus detection unit 2 is based on a prediction signal from the prediction unit 11, that is, a predicted defocus amount obtained based on the above-described one representative image equation (9). A method of determining whether or not the vehicle is along the signal by the deviation determination unit 12 will be described.

The departure determination means 12 is a means for determining whether or not the latest result of the focus detection means 2 significantly deviates from the trajectory predicted from the result of the prediction means 11 up to the previous time. That is, the predicted image plane moving speed u _n ′ obtained by the prediction unit 11
(Signal based on predicted defocus amount) and focus detection means 2
The absolute value of the difference from the image plane moving speed u _n (the signal based on the latest defocus amount) obtained as a result of the above is a predetermined value uexp (> 0).
In the above case, it is determined that the deviation has occurred.

When the deviation determination unit 12 determines that the deviation has occurred, the prediction control unit 13 does not use the predicted defocus amount obtained by the tracking unit 3 but uses the lens drive amount based on the predicted defocus amount obtained by the prediction unit 11. Is calculated, and when the departure determining unit 12 determines that there is no deviation, the lens driving amount is calculated based on the predicted defocus amount predicted by the tracking unit 3.

The lens driving unit 4 drives the lens based on the lens driving amount calculated by the prediction control unit 13.

Further, the prediction control unit 13 compares the predicted image plane moving speed u _{n + 1} ′ calculated by the prediction unit 11 at the time of the next focus detection with the stored predicted image plane moving speed u _n ′. Indicates a predetermined change, the lens driving amount is corrected based on the change, and the corrected lens driving amount is calculated. The lens driving unit 4 may drive the lens based on the correction lens driving amount calculated by the prediction control unit 13. The predetermined change includes, for example, a large absolute value of the difference (during a large acceleration motion) and a reversal of the sign (at the time of the closest passing).

An example of such correction will be described with reference to FIG.

In the case of a subject moving on the image plane as indicated by the thick solid line a in FIG. 7, if the lens is driven based on the image plane moving speed at time t _n , the lens is driven as indicated by the broken line b. At t _{n + 1} , there will be a large shift. Therefore,
In an automatic focus adjustment device capable of continuously changing the driving speed of the lens, the lens may be driven by performing polygonal approximation.

That is, as shown by the thin solid line d in FIG. 7, the time between time t _n and t _{n + 1} is finely divided, and the lens is driven at the image plane moving speed at that time. Further, in the automatic focus detection device which can only drive the lens intermittently, the dashed line c in FIG.
What is necessary is just to drive a lens like this.

-Second Embodiment-A second embodiment will be described with reference to FIG.

The second embodiment is an embodiment in which the configuration of the subject trajectory parameter 20 of the first embodiment is further embodied, and the other configuration is the same as that of the first embodiment.

In the first embodiment, since the constant C for determining the image formula stored in the subject trajectory parameter setting means 20 depends on the focal length, when the lens is attached to a lens having a different focal length, the constant C greatly deviates from the trajectory. Therefore, a lens information storage unit 24 is provided as a unit for storing lens information such as a focal length, and a subject trajectory parameter setting unit is further provided.
20 is stored as a constant E that does not depend on the focal length f and is expressed by the following equation (10).

Then, the trajectory constant calculating means 23 calculates a constant C for determining the image equation as shown in the following equation (11) from the above constant E and the focal length f of the lens information storage means 24.

Subsequently, based on the constant C for determining the image formula calculated by the trajectory constant calculation means 23, the trajectory determination means 10 obtains a movement trajectory signal and the prediction means 11 calculates a prediction signal in the same manner as in the above embodiment. . In this way, it is possible to accurately obtain a prediction signal using the same constant E even when the focal length f is different.

-Third Embodiment-A third embodiment will be described with reference to Figs. 9 and 10.

The first embodiment has a disadvantage that good results cannot be obtained if the image formula is largely different from the image formula stored by the trajectory determining means 10. Therefore, in the third embodiment, a plurality of trajectory parameters are stored in the subject trajectory parameters 20, and the trajectory determination means 10 determines the most suitable trajectory based on the trajectory parameters.

In the third embodiment, the object locus parameter setting means 20
Only the trajectory determining means 10 and the trajectory determining means 10 are different from those of the first embodiment. Only the subject trajectory parameter setting means 20 and the trajectory determining means 10 will be described. For simplicity, a case where four image formulas are used as representative image formulas will be described.

The subject trajectory parameter setting means 20 stores a constant C _i (i = 1, 2, 3, 4) for determining the image formula. Table Next, the trajectory determining means 10, with the the image plane movement velocity u _n based on the defocus amount output from the focus detection unit 2 and stored constants C, 4 single image type represented by FIG. 9 The most appropriate function to be selected.

First, the locus determining means 10 calculates the stored constants C1 and u _n from the (9) calculated by the focus detection unit 2 expression by a time T _{(1, n).} Similarly, the constant C _i (i =
The time T (i, n) converted for (1, 2, 3, 4) is calculated.

FIG. 10 shows an example of this result. Next, trajectory determination means
10 is (t ₁ , T _{(i, 1)} ), (t ₂ , T _{(i, 2)} ), ‥‥,
Calculate a linear regression line with a set of (t _n , T _{(i, n)} ) and calculate the slope b _i
Then, an amount σ _i representing how much the function of the trajectory determined by and the tangent α _i coincides with the straight line is calculated.

The quantity σ _i representing the degree of coincidence with a straight line may be calculated using a statistic such as, for example, the sum of squares of the residual, or a quadratic function when the function of the trajectory is obtained as a quadratic expression. A coefficient may be used. Locus determining means 10, sigma _i by selecting best matches image expression straight line (from among a plurality of image type determined by the constant C _i), the slope b _i of that time, Sehhen alpha _i, the image type The constants C _i to be represented are determined as b = b _i , α = α _i , and C = C _i .

Therefore, since in the case such as FIG. 10 is i = 2 coincides with the straightest _{b = b 2, α = α} 2, C = C 2 becomes, from the locus determining means 10 b _2, alpha ₂ moving track signal is output to the prediction unit 11, also the trajectory parameter signals related to the constant C ₂ is the object locus parameter setting means 20 is output to the prediction unit 11 relates.

Fourth Embodiment A fourth embodiment will be described with reference to FIG.

In the case of the third embodiment, when the relationship between the time t and the time T converted from the equation (9) becomes as shown in FIG. 11, there is a disadvantage that good results cannot be obtained. So the fourth
In this embodiment, an appropriate slope and tangent are calculated by interpolating between the determined slope b and tangent α based on the slope b and the tangent α calculated by the trajectory determining means 10.

First, the trajectory determination means 10 calculates the time T from the four image equations determined by the constants C _i (i = 1 to 4), that is, equation (9).
Calculate _{(i, n)} . Next, a section where it is considered that there is a true value is determined by σ _i . In the case shown in FIG. 11, C _i i
= 2 and i = 3), it can be considered that there is a true value (a straight line indicated by a chain line).

Therefore, the true values of the slope b and the tangent α are obtained by weighted averaging as in the following equation.

Here, W (σ) is a function representing weighting.

In this manner, the movement trajectory signal of the trajectory determination means 10 and the inclination b, the tangent α, and the subject trajectory parameter setting means 20
By determining the constant C for determining the image formula, which is the trajectory parameter signal, the prediction means 11 can determine the predicted trajectory more accurately.

-Fifth Embodiment-Next, a fifth embodiment will be described with reference to FIG.

In the fifth embodiment, a trajectory parameter of the subject trajectory parameter setting means 20 is input from the outside to calculate a constant C for determining an image formula, and a trajectory of the subject is determined by the trajectory determination means 10 based on the constant. Other configurations are the same as in the first embodiment.

The trajectory parameter input means 21 inputs the subject speed V and the foot length d from outside. Next, the trajectory parameter storage means 22 stores the value input from the trajectory parameter input means 21. The lens information storage means 24 stores information about the lens such as the focal length of the lens. Trajectory constant calculation means
23 is a constant C for determining the image formula based on the subject speed V and the foot length d stored in the trajectory parameter storage means 22 and the focal length f stored in the lens information storage means 24 (6).
It is calculated from the formula. The constant C calculated by the trajectory constant calculation means 23 is stored in the subject trajectory parameter setting means 20.
Then, the trajectory determination means 10 obtains a movement trajectory signal based on the constant C of the subject trajectory parameter setting means 20.

Actually, since the subject speed V and the foot length d cannot be input accurately, they are calculated as a plurality of constants Ci in the vicinity of the constant C calculated from the stored trajectory parameters. select the image type determined by the most suitable constants C _i from within, it may be obtained moving loci signal.

Further, the trajectory parameter input means 21 may be simple if it is possible to input one of several prepared values by directly inputting the value.

-Sixth Embodiment-A sixth embodiment will be described with reference to FIG.

In the first embodiment, the trajectory determining means 10 determines the image formula of the trajectory of the subject with respect to the image plane moving speed. However, when the extension of the lens can be detected, the simplification can be further achieved.

From the expressions (1) and (2), the expression representing 1 / x ² is as the following expression (13).

Here, if the time t is represented by an elapsed time t 'from a certain time, the following equation (14) is obtained.

Therefore, the following equation (15) is obtained.

However, Therefore, if the extension amount of the lens and the time are known, only one locus is determined. Out amount x _n of the lens is expressed by the sum of the defocus amount DF _n at that time the lens absolute position L _n during focus detection _{(x n = L n + DF} n).

The subject locus parameter setting means 20 stores Expression (15). The lens absolute position detecting means 25 detects an absolute distance from the lens position of the taking lens at infinity ∞.
The lens absolute position detecting means 25 may detect the absolute position of the lens by mounting an encoder in the lens.

Next, the trajectory determination means 10 determines the amount of lens extension based on the results of the focus detection means 2 and the lens absolute position detection means 25.
calculates x _n, by using the least square method on the basis of the 1 / x _n and t _n to (15) of the object locus parameter setting means 20, determining coefficients A, B, C, and.

Then, the predicting unit 11 performs the following based on the moving trajectory signal determined by the trajectory determining unit 10, that is, the signal regarding the coefficients A, B, and C
The lens extension amounts x _n-1 ′ and x _n are calculated by the equation (5), and the predicted defocus amount is calculated by the following equation (16).

P _n = x _n ′ −x _n−1 ′ (16) The departure determination unit 12 significantly deviates the latest result of the focus detection unit 2 from the predicted trajectory signal of the result of the prediction unit 10 up to the previous time. It is a means to determine whether or not
It is determined that the condition deviates when the condition is true.

| x _n ′ −x _n |> x exp (17) x _n ′: lens extension amount calculated from the predicted trajectory x _n : lens extension amount at the time of the latest focus detection xexp: predetermined amount (> 0) predetermined amount It is preferable that xexp is equal to or slightly larger than the defocus amount (generally, about 50 to 150 μm) for determining focus. Further, etc. to increase the predetermined amount xexp is where a large predicted defocus amount may be changed a predetermined value by the prediction defocus amount P _n. Needless to say, the determination may be made based on the predicted defocus amount _Pn as shown in the first embodiment.

In this embodiment, since the extension amount of the lens is directly obtained, the subject can be easily tracked even when the image plane moving speed changes abruptly.

The method of driving the lens based on the predicted trajectory signal may be another method. For example, a predicted trajectory signal for each fixed time shorter than the focus detection time interval is calculated, and the lens is driven based on the predicted trajectory signal. In this case, since the extension amount of the lens is directly obtained, there is no need to use the relative amount between the lens position and the image plane position, and the lens control can be simplified. Next, in the case where the subject approaches at a constant speed even if the deviation is not determined by the deviation determining means 12 this time, the feeding amount increases in proportion to 1 / (time) ² . (Equation (14)) Therefore, even if the lens is driven based on the latest result of the focus detection means 2, a large defocus occurs at the next focus detection. Therefore, assuming from equation (15) that the next focus detection is performed after the time Δt (generally, the focus detection time interval does not change rapidly), the next lens extension amount x _{n + 1} is calculated by the following equation. Is calculated by

Here, when E = (2At + B) Δt + AΔt 2, expressed as follows.

Therefore, when E is equal to or larger than a predetermined value, a correction is applied, and when E is smaller, the correction is not performed.

〔The invention's effect〕

In the present invention, the tracking means predicts the movement of the subject based on the results of the focus detections performed in the past several times to generate a tracking signal relating to the predicted movement amount, and the prediction means converts the information relating to the movement of the subject and the focus detection signal into Based on a trajectory function representing the trajectory of the subject determined based on the trajectory, a predicted movement signal that predicts the movement of the subject is generated, and when the lens is driven, it is determined whether the tracking signal or the predicted movement signal is to be used. The determination is made based on the result of the means.

As a result, when the latest focus detection signal deviates from the trajectory function of the predicted movement trajectory of the subject by a predetermined value or more, instead of driving the photographing lens based on the tracking signal obtained by the tracking means, the predicted trajectory is determined. Since the photographing lens is driven based on the function, even if the object crosses in front of the camera's focus detection device and the focus detection result is pulled, the camera shakes and moves away from the target object Even in this case, the photographing lens can always be driven to an appropriate focus position without being affected, and good photographing can be realized. When the latest focus detection signal does not deviate from the predicted trajectory function by a predetermined value or more, the photographic lens is not driven based on the trajectory function, but the photographic lens is driven based on the tracking signal obtained by the tracking means. The driving of the taking lens based on the tracking signal can follow the subtle movement of the main subject more appropriately than the driving of the taking lens based on the trajectory function, and can obtain a good focus. it can.

Further, according to the present invention, since the driving of the photographic lens in the future can be predicted from the trajectory function, overrun can be prevented beforehand even when the driving direction of the lens is reversed.

[Brief description of the drawings]

1 to 7 show a first embodiment of the present invention.
FIG. 1 is a main configuration diagram of the first embodiment, FIG. 2 is an example of a geometrical arrangement diagram of a subject and a camera, and FIG. 3 is a difference between a subject speed, a closest position at the time of photographing, and a focal length of a lens. FIG. 4 is a diagram showing the relationship between the time and the amount of feeding out, FIG. 4 is a diagram showing an example of an image formula obtained by normalizing the image plane moving speed, and FIG. 5 is a diagram showing a converted time T of the stored image formula. And FIG. 6 is a diagram showing a function of the image plane moving speed, FIG. 6 is a diagram showing a moving locus in the first embodiment, and FIG. 7 is a diagram showing correction of a lens driving amount when passing through the closest position at the time of photographing. . FIG. 8 is a configuration diagram showing a partial configuration of the second embodiment of the present invention. 9 and 10 show a third embodiment of the present invention.
FIG. 9 is a diagram showing a plurality of stored image formulas, and FIG. 10 is a diagram showing a moving locus in the third embodiment. FIG. 11 is a diagram showing a movement locus of the fourth embodiment of the present invention. FIG. 12 is a configuration diagram showing a partial configuration of the fifth embodiment of the present invention. FIG. 13 is a configuration diagram showing a partial configuration of the sixth embodiment of the present invention. [Description of Signs of Main Parts] 1... Photographing lens 2... Focus detecting means 3... Tracking means 4... Lens driving means 10. 13 predictive control means 20 subject trajectory parameter setting 21 trajectory parameter input means 22 trajectory parameter storage means 23 trajectory constant calculation means 24 lens information storage means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-28815 (JP, A) JP-A-63-159817 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 7/28-7/40 G03B 13/18-13/30

Claims (6)

(57) [Claims] A focus detection unit for detecting a focus adjustment state of a photographing lens and generating a focus detection signal; and predicting a movement of a subject based on a result of a past several times of a focus detection signal of the focus detection unit. An automatic focus detection device comprising: tracking means for generating a tracking signal relating to a predicted movement amount; and lens driving means for driving the photographing lens based on the tracking signal of the tracking means. Trajectory determining means for determining a trajectory function indicating the trajectory of the subject based on the focus detection signal of the means; and generating a predicted movement signal by predicting the movement of the subject based on the trajectory function determined by the trajectory determining means. A deviation determining means for determining whether or not the latest focus detection signal of the focus detection means deviates from the predicted movement signal generated by the prediction means. The departure determining means calculates a lens driving amount based on the predicted movement signal of the predicting means when it is determined to be a deviation, and outputs a tracking signal of the tracking means when it is not determined to be a departure. Prediction control means for calculating a lens driving amount based on the lens driving amount, wherein the lens driving means drives a lens based on the lens driving amount. 2. The prediction control means calculates current and next predicted image plane movement speeds based on a trajectory function determined by the trajectory determination means. 2. The automatic focus adjustment apparatus according to claim 1, wherein a correction lens driving amount obtained by correcting the amount is calculated, and the lens driving unit drives the lens based on the correction lens driving amount. 3. An object trajectory parameter setting means for storing information relating to a plurality of types of motions of an object, wherein the trajectory determination means is configured to determine an image plane moving speed based on the plurality of information stored in the object trajectory parameter setting means. 3. The trajectory function according to claim 1, wherein the trajectory function is determined, and a trajectory is determined by selecting a function that best fits the target subject from the trajectory functions. Automatic focus adjustment device. A lens information storage unit for storing information on the lens; an object trajectory parameter setting unit for storing a constant relating to the movement of the object independent of a focal length of the lens; a focal length information of the lens information storage unit; A trajectory constant calculating means for calculating a constant representing a moving trajectory from a constant of the subject trajectory parameter setting means, and outputting a signal of the trajectory number calculating means to the trajectory determining means. 2. The automatic focus adjustment device according to claim 1. 5. Lens information storage means for storing information about a lens, trajectory parameter input means for externally inputting parameters relating to movement of a subject, trajectory parameter storage means for storing input parameters, and the lens information storage Trajectory constant calculating means for calculating a constant relating to the movement trajectory of the subject based on the lens information of the means and the information of the trajectory parameter storage means, 4. The automatic focus adjustment device according to claim 3, wherein the information is stored by a setting unit. 6. The apparatus according to claim 1, wherein said subject trajectory parameter setting means sets a function representing a square of a reciprocal of an amount of extension of a lens as a function relating to a movement trajectory of the subject. The automatic focus adjustment device according to any one of the above.