JP2925245B2 - Drive control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device suitable for use in a camera lens control device or the like.

[Conventional technology]

In recent years, the development of video equipment such as video cameras, electronic still cameras, and camera-integrated VTRs has been remarkable, and the functions and operability have been particularly enhanced, and the size and weight have been reduced. Above all, camera-integrated VTRs have been spreading rapidly.
A significant reduction in size and weight has been achieved by reducing the number of parts and changing the structure itself.

By the way, taking a camera-integrated VTR as an example, a lens unit requires a relatively large space and components.

FIG. 4 shows an example of a so-called inner focus type structure in which the front lens is fixed, and the rear lens group performs zooming and focus adjustment, thereby making it possible to reduce the size of the lens unit. It is known as a configuration.

In the figure, 101 is a fixed front lens, 102 is a variable power lens (zoom lens), 103 is a stop, 104 is a fixed third lens unit, and 105 is a function of correcting the movement of the focal plane due to the movement of the zoom lens. This is a fourth lens unit (focus lens) having both a (compensator function) and a focus function.

When zooming is performed by moving the zoom lens in the lens system configured as shown in FIG. 4, the fourth group lens performs an operation having both a compensator function and a focusing function as described above. This is shown in FIG.

FIG. 5 shows the positional relationship between the zoom lens and the focus lens using the subject distance as a parameter, with the horizontal axis representing the zoom lens position and the vertical axis representing the focus lens position. As is clear from the figure, if the focus lens moves along a specific trajectory with respect to each object distance during the zoom operation, the zoom operation can be performed in focus without blurring. If it deviates from the trajectory, blur will occur.

A method of moving the focus lens according to a specific trajectory according to the subject distance during the zoom operation has been proposed in, for example, Japanese Patent Application Laid-Open No. 1-280709. In this method, the locus of FIG. 5 is divided into regions having substantially equal inclinations as shown in FIG. 6, and one speed is given to each region as a representative speed. During the zoom operation, the zoom lens and the focus lens are moved. One of the areas according to the positional relationship
When the lens is located in the area, the focus lens is moved at the representative speed of the area.

However, in the above method, the representative speed of each area is
Since the speed is determined for one zoom lens speed, if the zoom lens moving speed fluctuates due to, for example, variations in the zoom motor, a temperature difference, or a posture difference due to a camera angle, the locus in FIG. 5 will not be correctly followed. There was a problem.

On the other hand, for example, JP-A-1-319717 proposes a method of adjusting a focus lens driving device during a zoom operation by adjusting a count by which the representative speed is multiplied according to a change in an actual zoom speed. ing.

For example, the horizontal axis in FIG. 6 is divided into 16 equal parts. Now the zoom speed is designed at tele end (T) wide end (W)
Is set to the speed of moving in 7 seconds, the seventh
As shown in the figure, passing through one zoom zone 301, NTSC
In the case of the method, 26 vertical synchronization periods (26 Vsync) are required. N (Vsyn
c) If it is applied, the reference value of the zoom speed (Tω7se
Since the rate of change R _{ZS with} respect to c) can be expressed by R _ZS = N / 26 (1), during the zoom operation, the vertical synchronization period required to pass through the one zone is always measured, and 1 /
By multiplying the R _ZS in the representative speed, it becomes possible to perform the zooming at the moving speed of the focus lens 5 in response to changes in the zoom speed without causing blur.

[Problems to be solved by the invention]

However, in the above conventional example, when a variable resistance type encoder or the like is used for the zoom position detector 112, for example, as indicated by 801 in FIG. As a result, there is a problem that irregular changes occur without partial monotonous increase as shown by reference numeral 802.

When a boundary is provided for the output value of the zoom encoder and the zoom movement range is divided as shown in FIG. 6, the divided area has a characteristic as shown in FIG. 9 with respect to the position of the zoom lens. FIG. 9A shows a region length longer than a desired divided region length due to the influence of the non-linear portion in FIG. Also 90
In FIG. 2, the divided area value fluctuates due to the effect of non-monotonic increase indicated by 802 in FIG.

As described above, when the zoom speed is measured by the method described in the conventional example, it is determined that, for example, the portion at 901 is slower than the actual zoom speed, and the portion at 902 is determined to be much faster. Therefore, when this determination result is directly reflected on the focus lens moving speed during zooming,
There is a problem that an unnatural blur occurs in the image at the portions 901 and 902.

On the other hand, according to the present invention, the speed of the zoom lens is actually measured, and when the abnormal measurement data described above is obtained, the data is not used and the abnormal follow-up operation of the focus lens is prevented. However, for example, when the zoom operation is performed for the first time after the apparatus is turned on, since the zoom speed is not measured, after the first zoom operation is started, the _RZS is not changed until the measurement is completed. Not determined
There is a danger that the moving speed of the focus lens will not be properly controlled, resulting in blurring.

[Means for solving the problem]

SUMMARY An advantage of some aspects of the invention is to solve the above-described problem. The invention is characterized in that a first lens and a movement of the first lens are followed according to predetermined characteristics. A second lens to be driven; detecting means for detecting a moving speed or a moving amount of the first lens; and a first means for controlling a driving speed of the second lens based on a detection result of the detecting means. A control mode and a second control mode for forcibly driving the second lens at a predetermined speed irrespective of the detection result of the detection means can be set. And a control means for controlling the second lens to drive and control the second lens in the second control mode.

[Action]

Thereby, the control of the speed or the moving amount of the second lens or the moving body that follows the first lens or the moving body based on a predetermined relationship is always performed according to the actual moving speed of the first lens or the moving body. Can be precisely controlled,
For example, since the second lens or the moving body can be controlled with a standard value prepared in advance until the speed measurement of the first lens or the moving body is completed after the power is turned on, the operation starts. Optimal control can be performed immediately after, and when viewed with a zoom lens, even before the zoom speed measurement is performed, blurring during the zoom operation is suppressed to a minimum and a favorable zoom operation is achieved.

〔Example〕

Hereinafter, an embodiment of a drive control device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the control device according to the present invention.

6, reference numerals 101, 102, 103, 104, and 105 denote optical system elements having the same functions as those in FIG. 106, 107,
Reference numeral 108 denotes an actuator for driving the zoom lens 102, the diaphragm 103, and the focus lens 105, for example, a motor or the like.
06, 107, and 108 are drivers for controlling the driving, 112 and 113 are position encoders for detecting the positions of the zoom lens 102 and the focus lens 105, respectively, and 114 is a device that converts an image formed by the lens into a video signal. 115, an amplifier for amplifying the output signal of the image sensor 114, 116, a band-pass filter for extracting only high-frequency components effective for detecting the focus state of the output signal of the amplifier 115 , 117 is a focusing lens in a direction in which the high-frequency component is increased by the output signal of the bandpass filter 116.
A lens drive control microcomputer that performs control such as moving the zoom lens 105 to perform focusing or moving the zoom lens 102 and the focusing lens 105 simultaneously to perform a zoom operation as described in the conventional example, and 118 denotes an amplifier. The brightness of the subject is measured by the brightness level of 115 output signals,
This is a diaphragm control device that adjusts the opening amount of the diaphragm 103 to keep the brightness constant.

FIG. 2 shows a control flow chart of an operation control program stored in the lens drive control circuit 117 for operating the control device according to the present invention.

In the figure, 201 is a step for starting the control flow, 202 is a step for waiting for the power supply to the apparatus, and 203 is the three areas which have been passed among the divided areas of the zoom movement area 701 shown in FIG. Assuming that the time required for each pass is C ₃ , C ₂ , C ₁ , for example,
(The passing time is represented by the number of vertical synchronizing signals V-sync, and here, it is assumed that the time for passing through one area is 26 V-sync.) Reference numeral 204 denotes a zoom switch (not shown) which is operated to operate the zoom operation. 205 is a step for determining whether or not the time is passed, 205 is a step for obtaining the sum of the above-mentioned transit times C ₁ , C ₂ , and C ₃ , that is, a time C _SUM for passing through three divided areas, and 206 is a C _{SUM obtained in} step 205 Is a standard time (79 V-sync according to FIG. 7) for passing through the three divided regions of the zoom lens set in advance, and C _STD to obtain a ratio C _cont of a change in the zoom lens speed. 207 is a step for calculating the focus lens speed F _V by multiplying the C _cont summarized in step 206 by the storage speed in FIG. 6, and 208 is a focus lens driving speed calculated in step 207 while moving the zoom lens. Drive with F _V Step 209 is a step for ending the control flow. 210
Shows the control flow of the above-described series of steps 201 to 209 as one processing step.

In this embodiment, in consideration of variations in the encoder output, etc., based on the zoom speed measurement results of the past three divided area zoom lens has passed, the rate control scheme for determining the focus lens 5 driving speed F _V explain.

In the control flow of FIG. 2, when the execution of the control flow is started in step 201, the power supply is turned on in step 202. When the power is turned on, the process proceeds to step 203, in which variables C ₁ , C ₂ , and C ₃ that store the time required to pass each of the continuous zoom lens divided moving areas have standard values as temporary data (here, 26 ). This means that immediately after the power is turned on, there is no information on the past driving speed of the zoom lens, that is, the time required to pass through each divided area, and thus standard data is temporarily input. Thus, even if the zoom lens is driven immediately after the power is turned on, the zoom lens can be driven stably without malfunctioning.

Step 204 to determine the presence or absence of zooming in, if Zumusuitsuchi not shown is has been zooming operation has been performed, the process proceeds to step 205, for each divided region passing time C _1, C _2, C ₃ The sum C _SUM is calculated. Step 20
This is also the zoom lens drive speed when the standard value of the passage time of the zoom lens in the three divided areas is determined at 6, that is, the focus lens drive speed shown in FIG. Standard time
The ratio C _cont between C _STD and C _SUM is calculated.

Then, in step 207, C _cont is multiplied by the set speed of the corresponding area in each of the divided areas shown in FIG. 6, and in step 203, the focus lens driving speed F _V during the zoom operation on the temporary data substituted in is determined. And step 20
While driving the zoom lens 8, driven as to follow the focus lens 5 at a driving speed F _V.

As a result, the drive of the zoom lens can be controlled to follow the curve of FIG. 5 so as to accurately trace the curve of FIG. 5, and the occurrence of blur can be suppressed. When determining the drive speed of the focus lens, the actual drive speed of the zoom lens is measured and detected, and the follow-up speed of the focus lens is determined. Becomes possible.

As is clear from the above description, C _cont is equivalent to R _ZS shown in the above equation (1). R _ZS is the ratio in one divided area of the zoom movement range, whereas C _cont is 3
It is the value in the divided area. FIG. 2 shows that C _cont is calculated for temporary data in order to clarify the method of speed control processing. However, since C _cont can be handled as temporary data, step 205, step 206
It seems that it is practical to substitute temporary data immediately after C _cont without going through the above procedure.

By the above procedure, after the power is turned on, when the measurement of the zooming speed is not completed, first the temporary data and C _1, C ₂ and C ₃ C
Substituting into _cont , this is the focus lens driving speed
If caused to drive the zoom determines the F _V, without causing a large blur, it is possible to perform the zoom operation after power-on start.

In the flowchart of FIG. 2, the focus lens driving speed setting in the first zoom operation after the power is turned on has been described. Next, referring to FIG. 3, the driving speed of the zoom lens is measured, and the following driving speed of the focus lens is measured. Will be described. This control program is also the first
This is performed by a program stored in the drive control circuit 117. The configuration of the system is the same as that of FIG.

In FIG. 3, reference numeral 301 denotes a step for starting a control flow, 302 denotes a step for starting a zoom operation by performing a process indicated by 210 in FIG. 2 after power is turned on, and 303 denotes a step for starting the zoom operation. step for determining whether or not exceeds one boundary of the divided region as shown in the figure 701, 304 resets the counter C _Z for measuring the velocity through the divided region of the zoom lens in 0 step, 305 step is to increase the count value of the counter C _Z +1, 306 determines whether the zoom lens position from the divided regions likewise zoom lens and step 303 is currently measuring the zoom speed to an adjacent region has moved Step 307 is a step for determining whether or not a vertical synchronization signal has arrived.
Numeral 310 shifts the contents of the variables C ₃ , C ₂ , and C ₁ each storing the transit time of the past three divided areas described in FIG. ₂ by _one, and fetches the latest measured zoom speed into C ₁ . Thus, the step 311 for updating the data while leaving the past history, and 311 as shown in step 205 in FIG.
Time C ₁ , C ₂ , C ₃ required to pass through two divided areas C
_The step 312 for calculating the _SUM is a standard time required for passing through the three divided areas of the zoom lens which has been set in advance (step 79 in FIG. 7). sync) _Divide the sum C _SUM by C _STD and divide it by C _cont
313 is the C calculated in step 312
_The focus lens driving speed according to the actual zoom lens driving speed by multiplying _cont by the standard speed of each area shown in FIG.
Step for calculating a F _V, 314 discriminates whether the zoom operation is being performed step 315 drives the focus lens 5 at the focus lens 5 driving speed F _V drives the zoom lens step, 316 step This is a step of stopping the zoom operation for driving the zoom lens and the focus lens while tracing the locus of FIG. 5 according to the determination result of 314.

When the control flow is started in step 301, as shown in the control flow shown in steps 201 to 209 in FIG. 2, after the power is turned on, the operation waits for the operation of a zoom switch (not shown) and the zoom operation is performed in step 302. In this case, the zoom lens is driven using the standard value as the provisional data to start the zoom operation. Zoom encoder 11 during zoom operation
On the basis of the information from step 2, it is monitored in step 303 whether or not the boundary of one divided area as indicated by 701 in FIG. 7 has been exceeded.
The boundaries between the divided areas are determined based on encoder output changes as shown in FIG. The reason for monitoring the boundaries of the divided areas in step 303 is as follows. That is, if the zoom lens is located at point A in FIG. 7 after the start of the zoom operation, the distance from point A to the first boundary is shorter than the length of the actual area. Therefore, since the speed measurement value from the point A to the boundary includes a large error, the process is controlled so that the measurement of the zoom lens driving speed is not performed after the start of the zoom operation until the first boundary of the divided area is detected. Is done.

Counter C _Z for divided areas transit time measurement for detecting the driving speed of the step 304 in the zoom lens is reset to 0, it is increased +1 the value of the counter C _Z in step 305, and the next divided region in step 306 Detect the boundary of.

If it is determined in step 306 that the zoom lens has not moved to the next divided area, then in step 307 the vertical synchronizing signal V
-Wait for the arrival of sync. Upon detection of the vertical sync signal in step 307 back to step 305, it is incremented by one C _Z.

When the processing of step 305, step 306, and step 307 is repeated, and the boundary is detected in step 306,
Proceed to step 307. Counter would be either took many vertical synchronization period while the zoom lens is passed through the first divided region is stored in the C _Z. So step 30
In 8,309,310, to update shifted each of the three data by substituting C ₂ to C _1, C ₃ to C ₂ while substituting the latest count value C _Z to C _1.

For example, if C _Z is that it was 30 V-sync number, from C _1, C _2, respectively C ₃ is 26 as the initial value has been stored, C ₃
= 26, C ₂ = 26, C ₁ = 30. In this case, steps 311, 3
The new focus lens speed F _V determined based on the formula (1) from C _cont obtained in step 312 in step 313 in step 313 is more than that when three temporary data are used as initial values. also, slower by the amount of C ₁ is made from 26 to 30.

When new focus lens 5 speed F _V at step 313 is determined, to determine whether Zumusuitsuchi at step 314 continues to be operated, if it is operated step 315
Then, the zoom operation command is output to the actuator drivers 109 and 111, and the process returns to step 304. If the zoom switch has not been operated, the zoom operation is stopped at step 316 and the next zoom command is waited at step 314.

By executing the above program, when the zoom operation is started, it is possible to smoothly drive the zoom lens with the provisional data first and then shift to the operation based on the measurement data successively. The focus lens can be made to follow stably without largely deviating from the locus shown in FIG. 5, and the zoom operation can be performed without blurring.

〔The invention's effect〕

As described above, according to the drive control device of the present invention, in the control system including the first moving body and the second moving body that follows the first moving body based on a predetermined relationship,
The following speed of the second moving body is determined based on the result of measuring the moving speed of the moving body, so that high-precision and stable control can be performed. When the speed measurement of the main first moving body is incomplete, such as when performing the measurement, the first measurement is performed using the provisional measurement result.
When the second moving body is driven in accordance with the driving of the moving body, and the speed measurement of the main first moving body is completed,
Since the provisional measurement result is replaced with the true measurement result, the speed control of the second moving body can be performed without generating a large error even if the measurement data of the main first moving body is not obtained. It can be performed. Further, it is possible to smoothly shift from the speed control of the second moving object that is dependent on the temporary measurement data to the speed control of the second moving object that is dependent on the true measurement data. This is effective in a control system that drives the cas lens while maintaining a predetermined relationship.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment in which a drive control device according to the present invention is applied to lens control of a video camera, and FIG. 2 is a flowchart showing an initial control operation in the embodiment shown in FIG. FIG. 3 is a flowchart showing a control operation in a steady state according to the present invention. FIG. 4 is a diagram showing an example of a general inner focusing lens structure. FIG. 5 is a positional relationship between a zoom lens and a focusing lens. FIG. 6 is a characteristic diagram showing the object distance as a parameter. FIG. 6 divides the position of the zoom lens and the positional relationship of the focus lens into a plurality of moving regions, and sets the representative speed of the focusing lens for each divided region. FIG. 7 is a view showing a set state, FIG. 7 is a view for explaining speed measurement of a zoom lens, and FIG. 8 is a rotation angle of a position encoder for detecting a zoom lens position. FIG. 9 is a characteristic diagram showing the relationship between the position encoder rotation angle and the area determination level.

Claims (2)

(57) [Claims] A first lens; a second lens driven to follow the movement of the first lens according to predetermined characteristics; and a moving speed or moving amount of the first lens. Detecting means for detecting; a first control mode for controlling a driving speed of the second lens based on a detection result of the detecting means; and forcing the second lens regardless of a detection result of the detecting means. A second control mode for driving at a predetermined speed can be set, and when the first lens is driven for the first time after the power is turned on, the second lens is driven in the second control mode. A drive control device, comprising: control means for controlling so as to control. 2. The apparatus according to claim 1, wherein said control means controls said second lens based on provisional data corresponding to a predetermined moving amount or moving speed of said first lens. A drive control device characterized by being configured as described above.