JPH05107450A - Video-camera device - Google Patents

Abstract

PURPOSE:To enable natural and smooth focusing control without malfunction independently of the condition of a subject. CONSTITUTION:A video-camera device equipped with an autofocusing device by which a focusing system is operated on the basis of the signal that has been output from an imaging means 3 comprises extracting means 6 to 9 for extracting focusing signals corresponding to the degrees of focusing out of imaging signals; a calculating means 10 for obtaining an evaluated value, making an input signal of a focus signal, that indicates the degree of conformity in which the input signal conforms to a predetermined condition, on the basis of a prescribed input membership function, and also for outputting a control signal by substituting this evaluated value into a prescribed output membership function; and a control means 10 for performing at least one of focusing judging operation, restart judging operation, and focusing incapability judging operation of the autofocusing device on the basis of the control signal that has been output from the calculating means 10, and also for changing over the operating condition of the autofocusing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens control device suitable for use in video equipment such as video cameras and electronic still cameras.

[0002]

2. Description of the Related Art In recent years, video equipment such as video cameras and electronic cameras has been remarkably developed, and in order to improve the functions and operability thereof, functions such as an automatic focusing device (AF) have been standardly equipped. It has arrived.

The automatic focus adjustment device detects the sharpness of the screen from the video signal obtained by photoelectrically converting the subject image by an image pickup device or the like, and controls the focusing lens position so as to maximize it. The method of adjusting the focus by using the focus is becoming mainstream.

As the evaluation of the sharpness, in general, the strength of the high frequency component of the video signal extracted by the band pass filter (BPF) or the blur width of the video signal extracted by the differentiating circuit (the edge portion of the subject image) Width) detection strength is used.

This is because when a normal subject image is taken,
When the focus is out of focus, the level of the high frequency component is small and the blur width is wide, and as the focus comes in, the level of the high frequency component is large and the blur width is smaller, and when the focus is completely reached, respectively. Takes maximum and minimum values. Therefore, when the sharpness is low, the control of the focusing lens is driven in the direction in which the sharpness becomes higher as fast as possible, and the deceleration is slowed as the sharpness increases, and the peak of the sharpness peak is accurately measured. It is controlled to stop at.

By the way, in recent years, in various control fields, in order to be able to perform a more natural and situationally adapted control, a natural and situationally controlled control is introduced by incorporating an ambiguous judgment part into the control. The so-called fuzzy reasoning is used.

In such a control system, the degree of conformity with a preset condition is determined by using a predefined membership function for a plurality of pieces of information regarding control, and the result and the predefined output function are compared. The control amount is calculated from

That is, a plurality of pieces of control information are detected, a membership function prepared in advance is applied based on each of the detected information, and the information is collated with a preset rule. Then, the degree of conformity to the rule is quantitatively obtained, the result is substituted into the output membership function, an output membership function considering each situation is generated, and the control amount is calculated.

To give a concrete example, for example, by finally calculating the center of gravity of the outer shape of the output membership function,
A control output reflecting various ambiguities is obtained.

As described above, various control objects using fuzzy inference are conceivable. In the field of image pickup devices such as video cameras, however, there are various photographic situations such as the focus adjustment device. In a system that requires an operator's sensory judgment in order to perform appropriate control, it is extremely effective to perform human control that incorporates the ambiguous part.

[0011]

However, in the AF system which currently uses the fuzzy inference, the fuzzy inference is used to control the focus lens driving speed, and the focus adjustment operation is appropriately performed. However, it is not possible to improve accuracy in focusing, non-focusing determination, restart determination after focusing, determination of focusability, etc., which is performed by normal threshold control.
Depending on the shooting conditions, the focus may be out of focus and blur in the middle, the focus state may become unstable after focusing, or the focus lens may continue to move without being in focus. Was left.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a video camera having an automatic focusing device for performing a focus adjusting system based on a signal output from an image pickup means. In the apparatus, an extraction means for extracting a focus signal according to the degree of focusing from the image pickup signal, and an evaluation indicating the degree to which the focus signal is used as an input signal and which meets a preset condition for the input signal. A value is obtained on the basis of a predetermined input member function, and an arithmetic means for outputting a control signal by substituting the evaluation value into a predetermined output member function, and on the basis of the control signal outputted by the arithmetic means. Control means for performing at least one of a focus determination operation, a restart determination operation, and an unfocusable determination operation of the automatic focusing device, and switching the operating state of the automatic focusing device. The example was constructed.

[0013]

As a result, not only when the focus is adjusted, but also when switching the respective operation states such as the focus / non-focus determination operation, the restart operation, the in-focus determination operation, etc. However, there is no malfunction and natural and smooth control can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the control device of the present invention is applied to an automatic focus adjusting device for a video camera will be described below in detail with reference to the drawings.

First, an outline of an automatic focus adjusting device which is a target in this embodiment will be described.

There are various types of automatic focus adjusting devices for cameras, but in a device having an image pickup means for photoelectrically converting a subject image to obtain a video signal, such as a video camera, an electronic still camera, etc. From the sharpness of the subject image,
A method is known in which fineness is detected and the focus is controlled by controlling the position of the focusing lens so as to maximize the fineness.

A method of controlling the focusing lens drive speed in such a focus adjusting device is such that the blur width of the edge portion of the subject image is detected and the lens drive speed is changed according to the detected value. It has been proposed (for example, Japanese Patent Application No. 1-77063 by the applicant).

By the way, in such a system in which a signal component corresponding to the focus state is extracted from the video signal to perform focus detection, the signal component varies depending on the subject, its environment, etc., and is accurate and natural. Focus adjustment tends to be difficult.

Fuzzy reasoning, which has recently been used in various control fields, can be effectively applied to such control including ambiguity. In such a case, for example, high frequency in a video signal is used. A method of processing the signal component and the detected blur width of the subject by fuzzy reasoning to determine the speed and direction of the focusing motor for driving the focusing lens and performing automatic focus adjustment operation is possible. In addition to these speed and direction controls, various adjustments such as in-focus / non-in-focus determination, restart determination, in-focus determination, and the like are necessary for adjustment.

According to the present invention, fuzzy inference is used for these various judgments, so that accurate judgments can be made regardless of the subject condition, and mode transition can be appropriately performed without malfunction.

FIG. 1 is a block diagram showing an embodiment of an automatic focus adjusting device in a video camera device according to the present invention, and FIG. 2 shows a control operation of a system control circuit 10 for controlling the entire system in the block diagram of FIG. It is a flow chart for explaining.

In FIG. 1, reference numeral 1 denotes a lens group for focus (hereinafter referred to as a focus lens), which is controlled by a system control circuit 10 (to be described later) to transmit an optical axis by a focus motor 16 through a focus drive circuit 15. Driven in the direction. Reference numeral 2 denotes an aperture (iris) for controlling the amount of incident light, which is operated by driving the iris drive circuit 13 via the iris control circuit 12 and operating the ig meter 14 so that the video signal level is always constant. ..

The incident light enters through the focus lens 1 and the diaphragm 2, is imaged on the image pickup surface of the solid-state image pickup device 3 such as CCD, is converted into an electric signal, and is amplified to a predetermined level by the preamplifier 4. After that, it is supplied to the process circuit 5.
In the process circuit 5, the input image pickup signal is subjected to predetermined signal processing and converted into a standardized television signal, and a video output terminal, an electronic viewfinder (EVF), or a VTR integrated camera (not shown) is provided. In some cases V
It is output to the recording signal processing circuit of TR and the like.

Reference numeral 11 denotes a lens operation reading circuit for reading various control operations related to the lens such as manual / auto switching of focus, high speed shutter operation, and macro AF operation and supplying them to the system control circuit 10.

The output of the preamplifier 4 is supplied to the bandpass filter 6, and a high frequency component that changes according to the focus state is extracted from the video signal as a parameter for focus detection and is guided to the blur width detection circuit 7. Then, the blur width of the subject image on the imaging surface is calculated. The output of the blur width detection circuit 7 is information corresponding to the width of the edge portion of the subject image. The closer the focus state is, the smaller the width of the edge portion of the subject becomes, so that the edge width is minimized. The focus can be adjusted by driving the focus lens 1.

The focus detection method itself based on the blur width information is disclosed by the applicant of the present invention, for example, Japanese Patent Laid-Open No. 62-10361.
No. 6, JP-A No. 63-128878 and the like.

Since the high-frequency component signal and the blur width signal described above pass through the gate circuit 8 and the peak detection circuit 9 for setting the focus detection area (distance measuring frame) in the image pickup screen, the distance is measured in the screen. The peak value or the integral value within the range-finding frame limited to is obtained, and is supplied to the system control circuit 10 configured by, for example, a microcomputer that comprehensively controls the operation of the entire apparatus. In addition to this, the system control circuit 10 is also supplied with the detection values of the focus encoder 17 and aperture encoder 18, and is used for various controls.

Further, it is desirable to set a distance measuring area (focus area) according to the depth of field and the degree of focus. Therefore, the system control circuit 10 detects the depth of field from the various encoder information provided in the above-mentioned optical system, and sends the area switching signal to the gate circuit 8 to set the focus area suitable for the depth of field. To supply. For example, when the depth is deep or the focus degree is low, the area is set wide, and conversely, when the depth is shallow or the focus degree is high, the area is set narrow.

The system control circuit 10 determines the driving speed, direction, stop, restart, etc. of the focus lens 1 based on the time-series change of these information, and the focus drive circuit 15 performs control according to the determination result. A signal is output and the focus motor 16 is driven to move the focus lens 1.

FIG. 2 is a flow chart showing the overall flow of control operations performed by the system control circuit 10.

In the figure, step 1 A / D-converts the analog output output from the band pass filter 6 and the blur width detection circuit 7 of FIG. 1 for each field, and outputs desired data for the focusing operation. In the step of fetching and calculating and storing in a predetermined variable, the high frequency component (Cu), the blur width detection signal (Es) output from the blur width detection circuit 7, and the past average values (each AC
u, AEs), the high frequency component (Cu) and the blur width detection signal (Es) respectively, the difference value (dCu, dEs) and the difference value thereof, that is, the second-order difference value (d2Cu, d2E).
s), the average value of the past difference values (PdCu, PdEs),
Depth of field (IW), Es at the closest past focus
A difference value (hereinafter referred to as dPP) between the value and the current Es value is calculated and stored.

Step 2 is based on the above data,
This is a focus availability determination step for determining the availability of focusing using fuzzy reasoning. Fuzzy reasoning is performed using the ACu signal, d2Cu signal, d2Es signal, and IW signal input in step 1, and the current state is determined. If it is determined that focusing is not possible, the process proceeds to step 4 where focusing is impossible, and if it is determined that focusing is possible, step 3 proceeds to the hill climbing control step.

This hill-climbing control step detects changes in the outputs of the bandpass filter 6 and the blur width detection circuit 7 while moving the focus lens so that each output becomes an extreme value, that is, the focus signal level becomes the peak of the mountain. This is a mode for moving the focus lens to a desired position and searching for the focal point. Specifically, the sharpness information on the screen, that is, Cu signal, Es signal, and their difference value, dCu
The focus lens driving control is performed so that the sharpness information is maximized and the difference value is minimized by taking in the signal and the dEs signal.

The unfocusable processing step of step 4 means that the focus cannot be detected even if the focus lens is moved. Therefore, the focus lens can be stopped at a predetermined position to enable the focus. It controls to wait until.

Step 5 is a step for performing a focus determination process using fuzzy inference. Here, step1
Of the data input in, Cu signal, dCu signal, d
2Cu signal, Es signal, dEs signal, d2Es signal, d
This is a step in which fuzzy inference is performed using the PP signal, the PdCu signal, and the PdEs signal to determine whether the object is in focus or out of focus. If it is determined to be in focus, a stop command is issued to the focus motor for driving the focus lens, and if out of focus, the process returns to step 1 to capture new data.

Step 6 is a step for performing processing for stopping the focus motor when it is determined in step 5 that the focus is achieved.

Steps 7 to 10 can be referred to as non-focus determination blocks, and are routines for performing processing from detecting the non-focus to starting the movement again after stopping the focus lens. ste
It operates independently of the focus motor control routine up to p6.

Step 7 is a step for inputting data to be used for each subsequent determination. In addition to inputting or calculating the same data as step 1, Cu signal, Es signal when the focus motor is stopped and current Cu signal, Es.
The difference with the signal is calculated (hereinafter, dCup signal,
(dEsp signal), and stored in a predetermined variable.

Step 8 is a restart determination routine using fuzzy inference. When the focus lens is stopped and the subject needs to be focused again due to a change in the subject, it is detected and controlled. Is a step for performing processing for shifting to the next restart speed determination processing step.

If it is determined in step 8 to restart, the process proceeds to the restart speed determination processing step in step 9. This process is performed by finely moving the focus lens to the infinity side and the close side on the optical axis and moving to the front pin side with respect to the current position and the focus signal level when moving from the current position to the rear pin side. Is calculated, and in which direction and at what speed the focus lens should be driven is determined based on the sign and the magnitude relationship.

Then, based on this determination, the focus motor is driven and the focus lens is controlled.

On the other hand, FIG. 4 shows changes in typical Es, Cu, dEs, and dCu signals, which are the basis of the above-mentioned various input parameters, with respect to the focus lens moving position.

Both Es and Cu have a peak value at the in-focus point and have a mountain-like shape in which the level decreases as the distance from the in-focus point increases, but Cu has a certain level even if the in-focus point is separated. While the slope in the vicinity of the focal point is gentle, the level of Es drops remarkably when leaving the in-focus point, but has a very steep slope in the vicinity of the in-focus point.

That is, although Es has high focus detection accuracy in the vicinity of the focus, accurate focus detection is difficult at the foot of the mountain far from the focus, and Cu is a so-called large deviation from the focus. Even in the out-of-focus state, the focus lens can be driven to the focal point by climbing the mountain, but it is difficult to stop the focus lens accurately at the focal point because the inclination becomes gentle near the focal point. Therefore, according to the present invention, focus detection is performed by appropriately using these parameters in order to take advantage of the characteristics of these properties.

DEs and dCu are Es and Cu, respectively.
It is also apparent from the same drawing that the curve showing the difference value of has a characteristic in which the positive and negative maximum values are taken in the direction of approaching the in-focus point and become 0 at the in-focus point.

The above has described the processing of the automatic focus control operation in the video camera device of the present invention. The following is the main part of the control carried out in the system control circuit 10, and the determination of whether or not focusing is possible by the fuzzy reasoning and the focusing. Specific calculation processing of out-of-focus determination and restart determination will be described.

FIG. 3 is a control flow of determination by fuzzy reasoning, which is a control common to the above three determinations.

That is, in the figure, step 11 is a data input step of a member function used for rule determination in fuzzy reasoning. In the focusability determination, the ACu signal, d2Cu signal, d2Es signal, and IW signal are used to determine the focus determination. Then Cu signal, Es signal, dCu signal,
dEs signal, d2Es signal, dPP signal, PdCu signal, PdEs signal, Cu signal, dCu in the restart determination
Signal, Es signal, dEs signal, dCup signal, dEsp
The signal and the dPP signal are input.

Step 12 and step 13 use these input data to perform fuzzy inference and make a final decision.

The fuzzy inference used here will be briefly described. Specifically, it is performed as shown in FIG.

That is, when the data x and y are input to certain elements A and B and the rule as shown in (a) is set, the input data x is input to the input data x from the member function defined in the element A. , Big, the degree of evaluation (probability) Fx. Similarly, from the member type function of the element B and the input data y, the element B is Small.
The degree (probability) Fy is calculated.

Next, the output F of the antecedent part of the rule obtained now
The smaller one of x and Fy can be applied to the member shipping function of C, which is the consequent part of the rule, to finally obtain the value representing the likelihood of YES.

Through these judgments, the output membership function C is finally obtained as shown by the thick line portion in FIG.

For simplification of the explanation, here, the judgment method by one rule including two input member functions and one output member function is shown, but the actual fuzzy inference uses more member members. It consists of functions and rules.

In the present embodiment, when determining whether or not focusing is possible,
As shown in FIG. 6, 5 input member ship functions and 1
7 output member ship functions and 4 rules, in focus determination, as shown in FIG. 7, 7 input member ship functions and 1 output member ship function and 4 rules, in restart determination As shown in FIG. 8, fuzzy inference is performed by 6 input member functions, 1 output member function, and 3 rules.

When there are a plurality of rules in this way, the output membership function is made up of contours obtained by superimposing all contours at the time when all the conditions have been judged, and the control value output from the center of gravity is obtained. Seeking

With respect to each determination, the basis of each rule configuration of fuzzy reasoning and membership function configuration will be described below.

FIG. 6 shows a fuzzy reasoning rule for determining whether or not focusing is possible. 6-1 is an extreme value when the average value ACu signal of the high frequency component Cu signal and the average value AEs signal of the blur width signal Es are extremely small. It is in a dark state or there is no contrast (the average value is used to prevent malfunction due to noise or instantaneous screen changes), and normal focus control is often impossible. The rule set in consideration of this, 6-2 is 2 of Es and Cu.
When the next difference value d2Es signal and d2Cu signal are extremely high, the change of these signals is extremely sharp, and it is expected that it is difficult to perform the normal focusing operation because of the rapid panning operation. The rule 6-3 is set based on the above, and the rule 6-3 is set based on the fact that it is not necessary to perform the focusing operation when the depth of field IW is deep.

Then, each input data is substituted into these rules, the degree of conformity with the rule is calculated based on the input member function, and the result is the degree of conformity with the output member function, that is, the final control value is the center of gravity. It can be obtained by calculation. This calculation is performed exactly as in FIG.

More specifically, in the element forming each rule, for example, in the rule 6-1, the actual value of ACu is substituted into the membership function representing the condition "ACu is very low" (position on the horizontal axis). ), The degree to which the curve of "ACu is very low" of the input value is calculated (position on the vertical axis), and the curve of "ACu is very low" is restricted by the position of the vertical axis. To form. Similarly, "AE
Substituting the condition "s is very low" into the membership function of AEs, the degree of conformity to the condition is graphically obtained based on the curve and the position on the vertical axis.

Subsequently, the degree of satisfying these input conditions (the AND rule of each input condition is defined in the rule, AND pattern of both figures) is assigned to the "very difficult" curve of the focusing possibility membership function. And synthesize on that curve.

Similarly, with respect to the other rules, the input conditions are substituted into the member function, the matching degrees are combined on the output member function, and finally the input conditions drawn on the output member function are combined. The center of gravity of the composite figure of is calculated. This center of gravity is a comprehensive value obtained as a result of considering all the inputted various conditions, and is a control value (position on the horizontal axis of the output member-type function of the center of gravity coordinates) that best fits all the conditions.

Based on the control value thus obtained, it is possible to determine whether or not the focusing operation is possible, and how difficult the focusing operation is, not just the possible or impossible operation. If the contrast is completely low, the focus lens will be stopped, and if there is a possibility that focusing will be possible, the focus motor and focus drive circuit will be kept in a predetermined state without being completely cut off. The focus lens is located at the boundary between the focusable area and the non-focusable area, and if the focus is a little difficult, the focus lens does not stop completely but moves at a very slow speed. For example, it is possible to perform detailed control according to the shooting situation, and to perform control closer to the thinking and feeling of the operating person.

FIG. 7 shows a fuzzy inference rule in the focus determination. In 7-1 and 7-2, both the Es signal and the Cu signal are high in the focused state (both Es and Cu peak at the focused point). ), Past difference values PdEs, PdC
u becomes negative to some extent continuously (this is Cu,
Es is a mountain-shaped characteristic curve that takes a peak value at the in-focus point, and the difference value continues to rise near the in-focus point and becomes 0 at the in-focus point. Therefore, when the difference value becomes negative, the peak point That is, it may be very close to the focal point or it may be getting far away from the focal point.
Is high, it means that there is a very high possibility that the focal point is very close), and the second-order difference values d2Es, d
2Cu signal level is not high (that is, the difference value becomes 0 at the in-focus point and takes positive and negative values before and after its immediate vicinity,
The fact that the secondary difference value, which means a change in the difference value, is constant is likely to be close to the focus), and the current Es is not far from the closest Es value at the time of focus. (Es value is constant at in-focus point). Since Es has steep characteristics only in the vicinity of in-focus point as compared with Cu, Rule 7-
1 determines that the degree of focus is extremely high, and rule 7-2
Can be determined to be at least very close to the focal point.

For 7-3, Es is high near the focal point,
Since the second-order difference value d2Es is low and the mountain is being climbed toward the focal point, the past difference d of Es is d.
A rule for determining that Es is close to the focus set based on the fact that Es is positive and is high reflecting the steep characteristic near the focus, 7-4 is the level of Es in the non-focus state. Low, and the past difference value PdEs is also low (the Es characteristic curve does not become steep until it is close to the in-focus state and becomes flat as it becomes out of focus, so the difference value becomes small in the out-of-focus state), and now This is a non-focus determination rule that is set based on the fact that the difference dPP between the Es value of E and the Es at the time of previous focusing becomes large.

Therefore, the degree of conformity of the input data with respect to these rules is calculated by the input member function, and the respective calculation results are substituted into the output member function as described above to calculate. , Out-of-focus, slightly in-focus, almost in-focus, extremely in-focus, etc., the degree of focusing can be accurately and finely determined, and binary control is applied to a certain threshold as in the past. It is possible to perform extremely fine control as compared with what is performed.

That is, if the focus is very in focus, the focus lens is completely stopped, if the focus is almost in focus, the focus lens is driven at an extremely fine speed, and if the focus is slightly in focus, the speed of the focus lens is reduced. , If it is out of focus, it can be driven at high speed, but what is important here is not that four states can be obtained under these four conditions, but the degree of conformity with the above rules is output. It is possible to control the focus lens drive speed (including stop) in an extremely multi-stage analog manner because the control value that appropriately reflects the goodness of fit to each rule is calculated by substituting it in the membership function. This makes it possible to perform control that is more suited to the operator's thoughts, feelings, and judgments.

FIG. 8 shows the rules and the member function when the focus lens is brought from the in-focus state to the out-of-focus state due to movement or panning of the subject and the focus lens stopped and brought into focus is restarted.

Rule 8-1 is the average value dE of the difference values between the Es value when the focus lens is stopped and the current Es value.
Es when sp is large and the focus is closest in the past
The condition is set to restart if the difference value dPP between the current value and the current Es value is large.

That is, since the restart is performed when the focus state is changed to the out-of-focus state, when the focus state is deviated and the restart is required, the Es value is the focus and the focus lens. Is much smaller than the value when the lens stopped, but Es when the focus lens stopped in this rule.
The difference between the difference between the Es value at the closest past focus and the Es value at the closest past focus is added to the condition as the difference between the Es value at the closest past focus and the current Es value. Since there is a risk of malfunction when the Es value changes due to a change in the contrast of the subject later, etc., the Es value when the focus lens is stopped is compared at the same time, and Es value is higher than both levels. It specifies the condition that a restart is determined only when the value drops.

Rule 8-2 is the same as in 8-1, and Cu
The condition for performing the restart determination is set by simultaneously referring to not only the difference value of No. 2 but also the difference value with the Es value at the time of focusing. In addition, here, a rule 8-3 is provided to prevent an accidental restart even if a low-contrast subject arrives during panning and the Es value sharply decreases. When the value difference dEs is large in the negative direction, that is, when Es sharply decreases, the condition that restart is not performed is facilitated.

Then, the degree indicating how well the conditions of each rule are met when each input data is applied to these rules is obtained by the input member function, and these are combined on the output member function. To do.

Specifically, each input data is substituted into each input membership function according to the description of each rule, the value (probability) on the vertical axis of each function representing the matching degree is obtained, and these values are calculated. The value can be synthesized on the output member function and its center of gravity can be calculated to determine the final restartability. Then, as in the conventional case, the necessity of restarting depends on whether a certain condition is satisfied or not.
Rather than selecting by value, the possibility of restarting is determined according to the degree of conformity with each rule, and when restarting, the focus lens speed, mode, etc. can be controlled appropriately. In addition, it is possible to prevent a malfunction such as an accidental restart.

The contents explained above will be explained by returning to FIG. 3 again. The member operation routine step 12 is as follows.
A routine for determining the degree of evaluation of each element (eg, large, small, etc.) from the membership function and input data set in advance in the system control circuit, the rule determination routine step13 is a routine for setting preset rules and step12. A routine for obtaining a final output membership function from the evaluation degree of each element obtained in
It can be considered as a routine for obtaining the probability of the output membership function from the logical sum or logical product of the membership functions obtained in step 13, calculating the center of gravity of the outer shape, and performing various determinations by fuzzy inference.

As described above, according to the present invention, C
u signal, Es signal, dCu signal, dEs signal, PdCu
Signal, PdEs signal, dCup signal, dEsp signal, d
Using the PP signal and the IW signal as input information, fuzzy reasoning is performed based on a plurality of optimized rule groups, and as a result, focus control determination such as focus enable / disable determination, focus determination, restart determination, and the like is performed. It becomes possible to perform AF accurately, such as the state where the focus lens stopped with blurring, the state where it was erroneously restarted and wobbled, the state where the focus lens was still in motion even though it could not be focused, etc. It is possible to realize smooth AF in which harmful operations are reduced and there is little hesitation.

According to the above-described embodiment, the focus determination, the restart determination, and the focus non-determination are described as various focus control determinations, but the present invention is not limited to this, and for example, the determinations just described may be performed. In addition, fuzzy reasoning can be applied to the determination of the restart direction.

Further, fuzzy inference may be applied to all mode transition judgments of AF control.

[0078]

As described above, according to the video camera device of the present invention, the focusing determination operation and the restart determination operation of the automatic focusing device are performed based on the control signal obtained by the fuzzy operation. By performing the in-focus determination operation or the like, the determination operation and the operation state switching operation can be performed naturally and smoothly regardless of the condition of the subject.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a video camera device according to the present invention.

FIG. 2 is a flow chart for explaining a control operation of the video camera device according to the present invention.

FIG. 3 is a flowchart for explaining a fuzzy inference determination operation used in the video camera device according to the present invention.

FIG. 4 is a characteristic diagram showing characteristics of various parameters for determining a focus state used in the video camera device according to the present invention.

FIG. 5 is a diagram for explaining a calculation operation of fuzzy inference according to the present invention.

FIG. 6 is a diagram showing a membership function and a rule for explaining a focus availability determination operation using fuzzy inference according to the present invention.

FIG. 7 is a diagram showing membership functions and rules for explaining a focus determination operation using fuzzy inference according to the present invention.

FIG. 8 is a diagram showing membership functions and rules for explaining a restart determination operation using fuzzy inference according to the present invention.

Claims (1)

[Claims] 1. A video camera device equipped with an automatic focusing device for performing focus adjustment based on a signal output from an image pickup device, wherein the extracting device extracts a focus signal corresponding to the degree of focusing from the image pickup signal. And using the focus signal as an input signal, an evaluation value indicating the degree of conformity with a preset condition for the input signal is obtained based on a predetermined input membership function, and the evaluation value is determined as a predetermined output membership function. Computing means for outputting a control signal by substituting into the following, and a focusing determination operation, a restart determination operation, an unfocusable determination operation of the automatic focusing device based on the control signal output from the computing means. And a control unit for switching the operating state of the automatic focusing device.