JPH11341318A - Camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent motor power swing and to perform excellent image observation without generating large image blurs by increasing the drive force of a lens drive means more than the time when moving speed or moving acceleration is lower than a prescribed value, when the moving speed or moving acceleration of a camera is larger than a prescribed value. SOLUTION: When a zoom operation is performed, whether a panning/tilting SW is ON or OFF is confirmed. When the panning/tilting SW is ON, in the case that the speed (or acceleration) of panning/tilting is more than a prescribed value, the system goes into a high torque mode for temporarily increasing an application voltage to a zoom motor 13 and a focus motor 14. Thus, the output torque of the motors 13 and 14 is increased, and if sudden panning or tilting is performed and large acceleration is added to a zoom lens, the power swing of the motors 13 and 14 can be avoided. Therefore, accurate zooming and focusing control are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera system in which a user can arbitrarily perform panning and tilting by mounting a camera on a camera platform or the like.

[0002]

2. Description of the Related Art The above-mentioned camera system is widely used for monitoring. In a conventional surveillance camera system, a single focus pan focus lens or a low magnification zoom lens is used.

Recently, however, there has been an increasing demand for surveillance camera systems to increase the zoom magnification, to increase the zoom speed and autofocus, and to increase the speed of panning and tilting. Furthermore, a surveillance camera system using a rear focus lens as a lens unit and having an AF system using a TV signal is becoming mainstream.

Further, in the rear focus zoom lens system, the focus lens position changes corresponding to the zoom lens position at a certain subject distance.
As a motor for zoom drive and focus drive,
A stepping motor that can know a current lens position with a resolution of several μm from the number of pulses from an initial position (reset position) is often used.

More specifically, a feed screw is formed on the output shaft of the stepping motor, and screwed with a rack attached to the lens frame to directly transmit the rotation of the motor to the lens group, thereby setting the position of the lens group to one. Position control is performed at the pulse (several μm) level.

[0006]

However, when the lens is driven directly without using the deceleration means, the driving torque of the lens is reduced. During normal driving, the drive torque margin may be set low in order to suppress power consumption and generated noise, but when acceleration is applied to the lens, a state equivalent to increasing the lens weight is obtained. Therefore, the torque required to drive the lens becomes larger than the output shaft torque of the motor, and a step-out phenomenon in which the lens cannot be driven normally occurs in the motor. For this reason, when a pan head on which a camera is mounted suddenly pans or tilts and a large acceleration acts on the lens, for example, a focusing lens position corresponding to a variable magnification lens position shifts, and an appropriate camera image is obtained. Can not be obtained.

[0007]

According to a first aspect of the present invention, there is provided a lens driving unit for driving a lens mounted on a camera, and a panning unit for the camera.
In a camera system having camera moving means such as a camera platform for performing tilting or a combined operation thereof, when the moving speed or the moving acceleration of the camera by the camera moving means is a predetermined value or more, the moving speed or Control means is provided for increasing the driving force of the lens driving means as compared with when the moving acceleration is lower than the predetermined value.

That is, when sudden panning or tilting at a level that would normally cause the drive motor to lose synchronism is performed, the motor output torque is increased by temporarily increasing the amount of current supplied to the motor. Step-out is prevented, and good image observation is possible without generating large image blur.

Specifically, when the camera moving means has a DC motor as a driving source, the control means determines whether the camera moving means has a stepping motor based on a voltage value applied to the DC motor. Based on the current value applied to the camera, it is determined whether or not the moving speed or moving acceleration of the camera is equal to or more than a predetermined value by calculating the motor rotation speed or the like.

The present invention is particularly suitable when the lens drive means is of a direct drive type in which a feed screw formed on an output shaft of a drive source is engaged with a rack attached to a lens.

Further, in the second invention of the present application, the control means for moving the lens to the reset position when the moving speed or the moving acceleration is equal to or more than a predetermined value is provided.

Specifically, when the moving speed or the moving acceleration is equal to or more than a predetermined value, the zoom lens is moved to the wide end or the focus lens is moved to a position on the long photographing distance side. Thus, even if some motor loss of synchronism occurs, the observer does not feel the image blur by increasing the depth of field or keeping the subject from the shortest shooting distance to the long shooting distance within the depth. Only Moreover, if the lens is moved to the reset position and the position where the movement is stopped is recognized by the control means as a new reset position,
Even after rapid panning or tilting has been performed, accurate zoom and focus control can be performed.

In the third aspect of the present invention, the control means for stopping the operation of the lens driving means when the moving speed or the moving acceleration of the camera by the camera moving means is equal to or more than a predetermined value is provided.

That is, by stopping the driving of the motor, it is possible to reliably prevent the motor from stepping out, and to perform accurate zoom and focus control even after rapid panning or tilting is performed. .

When the driving source of the camera moving means is a stepping motor, even if the driving of the motor is stopped, the motor is energized to keep the motor in a magnetically stable state. It is desirable to prevent the lens from easily moving even if it is added.

[0016]

(First Embodiment) FIG. 1 is a main sectional view of a rear focus zoom lens constituting a camera system according to a first embodiment of the present invention. Reference numeral 1 denotes a front lens group, 2 denotes a variable power lens group, 3 denotes an afocal lens group, and 4 denotes a focus lens group.

Reference numeral 5 denotes a fixed lens barrel for holding the front lens group, and 6
Denotes a V-moving ring for holding a zoom lens group, 7 denotes an afocal ring, 8 denotes an RR moving ring for holding a focus lens group, 9
Reference numeral denotes a rear barrel having a mounting portion for an imaging CCD substrate. Reference numeral 10 denotes a zoom rack, which is attached to the V-moving ring 6 without play in the optical axis direction. Reference numeral 11 denotes a focus rack, which is attached to the RR moving ring 8 without play in the optical axis direction, similarly to the zoom rack 10.

Reference numeral 12 denotes an iris meter, 13 denotes a zoom stepping motor (hereinafter referred to as a zoom motor), 1
Reference numeral 4 denotes a focus stepping motor (hereinafter, referred to as a focus motor).

The zoom rack 10 and the focus rack 11 are screwed into a feed screw 13a formed on the output shaft of the zoom motor 13 and a feed screw 14a formed on the output shaft of the focus motor 14, respectively. Is transmitted to the V moving ring 6 and the RR moving ring 8 as a driving force in the optical axis direction.

The motors 13 and 14, the feed screw 13
The a, 14a and the racks 10, 11 constitute lens driving means described in the claims.

Here, when a stepping motor is used, since the motor rotation angle with respect to the number of stepping pulses is constant, the stepping pulse can be used as it is as an output signal of the increment type encoder, and no special encoder is added. There is an advantage that it may be. However, reset SW for initialization of position information and detection of reset position
is necessary.

In the present embodiment, although not shown, a photo interrupter is used as a zoom and focus reset switch, and the zoom-side reset reference position is set at the optical Wide end, and the focus-side reset reference position is set at the focus side. It is set at the 3m position.

The rear focus lens configured as described above is used as a camera with an imaging CCD substrate and a lens control substrate attached thereto. The lens control board includes a CPU (control means) for controlling the driving of the motors 13 and 14.

The camera C constructed as described above
As shown in FIG. 2, the camera is housed in the main body 22 of the camera platform (camera moving means) 21 and panned in the direction of arrow P or tilted in the direction of arrow T by a panning and tilting mechanism (not shown). Or

Reference numeral 23 denotes a remote control box having a power switch 24, panning switches 25a and 25b, tilting switches 26a and 26b, and zooming switches 27a and 27b. When the operator operates each switch, panning, tilting, and zooming of the camera C are remotely controlled. As described above, a surveillance camera system using the camera is constructed.

Next, the operation of the camera system (particularly, CPU) from power-on to focusing operation will be described with reference to the flowchart of FIG.

In step 1, the power supply of the camera system
N, the zoom motor 13 and the focus motor 1
4 is energized.

In step 2, the zoom motor 13 and the focus motor 14 are driven to the reset reference position where the output of the photo interrupter, which is the reset SW, switches from Hi to Lo, ie, the variable power lens group 2 is moved to Wide.
At the end, the focus lens group 4 is moved to a position of 3 m.

In step 3, it is determined whether or not a zoom operation has been performed. If the zoom operation has been performed, the process proceeds to step 4.

In step 4, it is checked whether the panning and tilting switches are ON and OFF. If the panning / tilting SW is ON, it is determined in step 5 whether the panning / tilting speed (or acceleration) is equal to or higher than a predetermined value.

Here, whether the panning or tilting speed (or acceleration) is large or small is determined by detecting the applied voltage if the panning motor or the tilting motor is a DC motor, or detecting the applied current if the panning motor or the tilting motor is a stepping motor. This is performed by calculating the number of rotations.

If the panning and tilting speeds (or accelerations) are equal to or higher than a predetermined value, the process proceeds to step 6 where a high torque mode in which the voltage applied to the zoom motor 13 and the focus motor 14 is temporarily increased. enter.

As a result, the output torque of the motors 13 and 14 can be increased, and even if rapid panning or tilting is performed and a large acceleration is applied to the zoom lens, the motors 13 and 14 lose synchronism. Can be avoided. Therefore, even if rapid panning or tilting is performed, accurate zoom and focus control can be performed, and the focused state on the subject can be maintained.

When the zoom operation is not performed in step 3, when the panning / tilting switch is OFF in step 4, and when the panning / tilting speed is lower than the predetermined value in step 5, the zoom motor is operated. 13 and a low torque mode (initial mode) in which the voltage applied to the focus motor 14 is lower than the high torque mode.

After entering the high torque mode in step 6,
In step 7, the panning and tilting switches are ON
It is confirmed whether or not the operation is continued. If the switch is OFF, the process returns to the low torque mode in step S8.

In this embodiment, the zoom motor 13 and the focus motor 14 are stepping motors.
As a means for increasing the output torque, the case where the applied voltage value is increased has been described. In addition, the waveform of the drive signal may be changed from a Sin waveform to a rectangular waveform, or the applied current value may be increased (such as a zoom motor and (When the focus motor is a DC motor).

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
4 illustrates an operation flow from power-on of the camera system according to the embodiment to completion of panning and tilting. Since this operation flow is used for the camera system described in the first embodiment,
The same reference numerals as in the first embodiment are used for the components of the camera system. In step 101, power is supplied to the zoom motor 13 and the focus motor 14 by turning on the power of the camera system.

In step 102, the zoom motor 13 and the focus motor 14 are driven to the reset reference position where the output of the photo interrupter, which is the reset SW, switches from Hi to Lo, ie, the variable power lens group 2 is moved to Wi.
The focus lens group 4 is moved to the 3 m position at the de end.

In step 103, it is confirmed whether or not a zoom operation has been performed. If the zoom operation has been performed, the process proceeds to step 104.

In step 104, it is confirmed whether the panning and tilting switches are ON and OFF. Panning,
If the tilting switch is ON, it is determined in step 105 whether the panning and tilting speed (or acceleration) is equal to or greater than a predetermined value. Note that the magnitude of the panning / tilting speed (or acceleration) is determined in the same manner as in the first embodiment if the panning / tilting speed (or acceleration) is equal to or greater than a predetermined value. To enter the high torque mode in which the voltage applied to the zoom motor 13 and the focus motor 14 is temporarily increased.

As a result, the output torque of the motors 13 and 14 can be increased, and the motors 13 and 14 lose synchronism even when a large acceleration is applied to the zoom lens due to rapid panning or tilting. Can be avoided. Therefore, even if rapid panning or tilting is performed, accurate zoom and focus control can be performed.

In step 106, the variable power lens group 2 is forcibly moved to the Wide end which is the reset reference position, and the focus lens group 4 is forcibly moved to the 3m position which is the reset reference position. Further, in step 107, the reset reference positions of these lens groups 2 and 4 are redefined.

As described above, the depth of field can be increased by moving the variable power lens unit 2 to the Wide end, and by moving the focus lens unit 4 to the 3 m position, from the shortest photographing distance of 1 m. All subjects up to infinity can be kept within the depth. As a result, if the acceleration applied to the lens is considerably large,
The observer hardly notices blurring of the image even if the image is out of sync.

Further, by returning the variable power lens group 2 and the focus lens group 4 to the reset reference position and redefining the reset reference position, even if the motors 13 and 14 lose synchronism, the subsequent lens control can be performed. Can be performed normally.

If the zoom operation has not been performed in step 103, if the panning / tilting switch is OFF in step 104, or if the panning / tilting speed is lower than a predetermined value in step 105, the zoom motor 13 and a low torque mode (initial mode) in which the voltage applied to the focus motor 14 is lower than the high torque mode. Further, the variable power lens group 2 and the focus lens group 4 are also maintained at the positions at that time.

After entering the high torque mode in steps 106 and 107, in step 108, it is checked whether the panning and tilting switches are continuing to be ON, and
In the case of F, in step 109, the mode is returned to the low torque mode.

In this embodiment, the motors 13 and 14 are also provided.
As a means for increasing the output torque, the waveform of the drive signal may be changed from a Sin waveform to a rectangular waveform, or the applied current value may be increased (when the zoom motor and the focus motor are DC motors).

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
4 illustrates an operation flow from power-on of the camera system according to the embodiment to completion of panning and tilting. Since this operation flow is used for the camera system described in the first embodiment,
The same reference numerals as in the first embodiment are used for the components of the camera system. In step 201, when the power of the camera system is turned on, power is supplied to the zoom motor 13 and the focus motor 14.

In step 202, the zoom motor 13 and the focus motor 14 are driven to the reset reference position where the output of the photo interrupter, which is the reset SW, switches from Hi to Lo, that is, the variable power lens group 2 is moved to Wi.
The focus lens group 4 is moved to the 3 m position at the de end.

In step 203, it is confirmed whether or not a zoom operation has been performed. If the zoom operation has been performed, the process proceeds to step 204.

In step 204, it is confirmed whether the panning and tilting switches are ON and OFF. Panning,
If the tilting switch is ON, it is determined in step 205 whether the speed (or acceleration) of panning and tilting is equal to or greater than a predetermined value. The panning / tilting speed (or acceleration) is determined in the same manner as in the first embodiment if the panning / tilting speed (or acceleration) is equal to or greater than a predetermined value. Then, the supply of the drive pulse signal to the zoom motor 13 and the focus motor 14 is stopped, the motors 13 and 14 are stopped, and the driving of the lens groups 2 and 4 is stopped.

As a result, even if rapid panning or tilting is performed and a large acceleration is applied to the zoom lens, the driving itself of the motors 13 and 14 is stopped.
It is possible to reliably prevent these steps from falling out.

However, even if the supply of the drive pulse signal to the motors 13 and 14 is stopped, the power supply for maintaining the motors 13 and 14 in a magnetically stable state (magnetically attracting the magnet and the stator) is not performed. Keep doing. This is because if the power supply to the motors 13 and 14 is completely cut off, the magnet and the stator will not be attracted to each other, and will be in a magnetically unstable state. Since it changes easily from the regular step position, while suppressing such a change in the stop position,
This is because even if the stop position slightly changes, the magnet and the stator automatically return to the normal step position due to the attraction.

If the zoom operation is not performed in step 203, if the panning / tilting switch is OFF in step 204, and if the panning / tilting speed is lower than the predetermined value in step 205, the low torque is applied. Mode (initial mode).

After stopping the driving of the motors 13 and 14 in step 206, it is checked in step 207 whether the panning and tilting switches are continuing to be turned on.
In the case of the FF, at step 208, the motors 13 and 14 are set to be in a state where they can be driven again. In each of the above embodiments, the camera system using the direct drive type lens drive unit in which the rack on the lens side meshes with the feed screw formed on the motor output shaft has been described, but the present invention is not limited to the direct drive type. The present invention can also be applied to a camera system using the lens driving means.

[0056]

As described above, according to the first aspect of the present invention, the amount of current supplied to the motor is temporarily reduced when abrupt panning or tilting at a level that causes the drive motor to step out is performed. Since the lens driving force is increased by, for example, increasing the number of times, motor out-of-step can be prevented, and good image observation can be performed without generating large image blur.

According to the second aspect of the present invention, the lens is moved to the reset position (the wide-angle end of the zoom lens) when the panning or the tilting at a level that normally causes the drive motor to step out is performed. To the position of the focus lens or to the position on the long shooting distance side).
It is possible to increase the depth of field and to fit the subject from the shortest shooting distance to the long shooting distance within the depth, so that the observer does not feel blurred image. In addition, by moving the lens to the reset position and re-recognizing the stop position after the movement as a new reset position, accurate zoom and focus control can be performed even after rapid panning or tilting is performed. be able to.

In the third aspect of the present invention, the operation of the lens driving means is stopped when abrupt panning or tilting at a level which normally causes the drive motor to step out is performed. Step-out can be reliably prevented, and accurate zoom and focus control can be performed even after rapid panning or tilting is performed.

When the driving source is a stepping motor, if the motor is stopped and the motor is kept energized to keep the motor in a magnetically stable state, it can be easily applied even if an impact or the like is applied. It is possible to prevent the lens from moving.

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view of a rear focus zoom lens used in a camera system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of the camera system.

FIG. 3 is an operation flowchart of the camera system.

FIG. 4 is an operation flowchart of a camera system according to a second embodiment of the present invention.

FIG. 5 is an operation flowchart of a camera system according to a third embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 front lens group 2 variable power lens group 3 afocal lens group 4 focus lens group 5 fixed lens barrel 6 V moving ring 7 afocal ring 8 RR moving ring 9 rear lens barrel 10 zoom rack 11 focus rack 12 iris meter 13 zoom motor 14 Focus motor

Claims (11)

[Claims] 1. A camera system comprising: lens driving means for driving a lens attached to a camera; and camera moving means for moving the camera, wherein a moving speed or a moving acceleration of the camera by the camera moving means is a predetermined value. A camera system comprising: a control unit that increases the driving force of the lens driving unit when the moving speed or the moving acceleration is lower than the predetermined value. 2. The method according to claim 1, wherein the lens driving means includes a driving source, a feed screw formed on an output shaft of the driving source, and a rack attached to the lens and meshing with the feed screw. The camera system according to claim 1, wherein: 3. The camera system according to claim 1, wherein said camera moving means is a pan head capable of performing at least one of a panning operation and a tilting operation. 4. A camera system comprising: lens driving means for driving a lens attached to a camera; and camera moving means for moving the camera, wherein a moving speed or a moving acceleration of the camera by the camera moving means is a predetermined value. When the above is the case, the camera system moves the lens to a reset position. 5. The camera system according to claim 4, wherein the lens is a zoom lens, and the reset position is a wide end. 6. The camera system according to claim 4, wherein the lens is a focus lens, and the reset position is a position on a long shooting distance side. 7. The control unit according to claim 4, wherein after stopping the lens at the reset position, the control unit recognizes the stop position as a new reset position.
The camera system according to any one of the above. 8. A camera system comprising: lens driving means for driving a lens attached to a camera; and camera moving means for moving the camera, wherein a moving speed or a moving acceleration of the camera by the camera moving means is a predetermined value. When the above is the case, the camera system further comprises control means for stopping the operation of the lens driving means. 9. The camera moving means has a stepping motor as a drive source, and the control means stops the operation of the lens driving means when the moving speed or the moving acceleration is equal to or more than a predetermined value. 9. The camera system according to claim 8, wherein power is supplied to maintain the stepping motor in a magnetically stable state. 10. The camera moving means has a DC motor as a drive source, and the control means adjusts a moving speed or a moving acceleration of the camera based on a voltage value applied to the DC motor. 2. The method according to claim 1, wherein whether the value is equal to or greater than a predetermined value is determined.
10. The camera system according to any one of items 1 to 9. 11. The camera moving means has a stepping motor as a drive source, and the control means controls the moving speed or the moving acceleration of the camera based on a current value applied to the stepping motor. 10. The camera system according to claim 1, wherein it is determined whether or not the value is equal to or more than a predetermined value.