JPH0832861A - Driving device for lens for television camera - Google Patents

Abstract

PURPOSE:To reduce the number of signal input lines and to simplify the line configuration by allowing the driver to receive a video signal and a focus drive signal and selecting the automatic focus operation based on the video signal or the focus operation based on the focus drive signal. CONSTITUTION:The driving device is provided with an automatic focus circuit 21 driving a focus device 10 based on a video signal to make automatic focusing, a signal input line 5a receiving a control section comprising the video signal or the focus drive signal as to the drive of the focus mechanism 10 with the focus drive signal received separately, a discrimination circuit 23 discriminating the video signal based on the control signal and a changeover circuit 22 selecting a transmission signal to the focus mechanism 10 based on the discrimination by the discrimination circuit 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for driving a focus mechanism in a lens for a television camera,
In particular, the present invention relates to a lens driving device for a television camera, which switches between an autofocus operation for automatically focusing on the basis of a video signal being taken and a focus operation by a separately input focus drive signal.

[0002]

2. Description of the Related Art Conventionally, a lens driving technique in a surveillance television camera or other television cameras, which controls the drive of a focus mechanism based on a video signal being taken to obtain an autofocus function is well known. Has been.

In addition, as described above, the autofocus operation is performed based on the video signal during photographing to obtain a photographed image corresponding to the change of the subject, and the television camera is installed on a pan / tilt pan head. Therefore, it is possible to remotely control the driving of the platform and the lens driving of the focus mechanism and the like. In this case, in a specific shooting shot, there is a demand to drive the focus mechanism to a fixed focus position by a focus drive signal instead of the autofocus operation. The focus drive signal by the remote operation may be registered in advance in a preset mechanism so as to obtain a predetermined shooting shot, and the drive signal may be output according to the information to automatically perform a predetermined operation.

As a drive system for a television camera lens that can meet the above requirements, a drive system as shown in FIG. 3 can be considered. That is, the lens unit 3 of the television camera 1 is provided with a focus lens 11 that is movable in the optical axis direction as the focus mechanism 10, and the focus motor 13 that moves the focus lens 11 to a predetermined position and the focus motor 13 are driven by the focus motor 13. A motor drive circuit 12 that outputs a signal is installed. The image formed on the CCD 15 installed in the camera body 2 of the television camera 1 is converted into a video signal by the camera circuit 16 and sent to the control signal generation circuit 7 of the controller 6.

On the other hand, the video signal is input to the second signal input line B of the lens unit 3 from the control signal generation circuit 7 of the controller 6, the video signal is sent to the autofocus circuit 21, and the autofocus circuit 21. Outputs an autofocus drive signal by so-called hill-climbing control based on the detection of the frequency component of the video signal. The output signal of the autofocus circuit 21 is input to the input section IN1 of the switching circuit 22.

Further, the lens unit 3 receives a focus drive signal (DC signal) from an external controller 6 for remote operation and the like from a third signal input line C, and a switching signal to the first signal. The input signal is input from the input line A, the third signal input line C is connected to the input section IN2 of the switching circuit 22, and the focus drive signal is input in parallel with the autofocus drive signal. Focus mechanism according to 22 switching operations
It is alternatively output to the motor drive circuit 12 of 10. And
The switching circuit 22 is configured to be switched based on the switching signal from the first signal input line A.

According to the above configuration, when performing the autofocus operation, the switching circuit 22 receives the switching signal according to the autofocus mode signal, and the switching circuit 22 receives the switching signal.
Sends the autofocus drive signal from the autofocus circuit 21 to the motor drive circuit 12 by conducting the contact on the autofocus side, and moves the focus lens 11 based on the video signal currently being shot for automatic focusing. To do. On the other hand, when performing a remote focus operation, a switching signal according to a remote focus mode signal is input to the switching circuit 22, and the switching circuit 22 switches so that the remote focus side contact is turned on to output the focus drive signal to the motor. The signal is sent to the drive circuit 12, and the focus lens 11 is moved based on this signal to focus on a predetermined position.

[0008]

However, in the driving system of the television camera lens as shown in FIG. 3, the signal input lines A to C corresponding to the switching signal, the video signal, and the focus driving signal, respectively. The number of strands of the connecting cable with the external controller is large, the number of terminals of the connecting connector is also large, and the connection structure of the signal input line is complicated and complicated.

The present invention has been made in view of the above circumstances, and when the video signal and the focus drive signal are input to switch between the autofocus operation and another focus operation, the signal input line is reduced and simplified. It is an object of the present invention to provide a lens driving device for a television camera as described above.

[0010]

In a lens driving device for a television camera of the present invention which achieves the above object, a focusing mechanism is driven by an image signal detection system based on a video signal being photographed to perform automatic focusing. One signal input line to which a control signal composed of the video signal or the focus drive signal is input, and the control signal, which has an autofocus circuit for performing the drive of the focus mechanism by a separately input focus drive signal. In response to the presence or absence of the sync signal included in the video signal, a determination circuit that determines whether or not the mode is the autofocus mode, and the autofocus drive signal and the focus drive signal by the autofocus circuit are input to the input section, and the determination is performed. Based on the discrimination of the circuit, Further comprising a switching circuit for switching the output signal to said auto-focus drive signal and a focus drive signal and is characterized in.

[0011]

According to the driving device for a television camera lens of the present invention as described above, when the autofocus operation is performed based on the input of the video signal, the control signal by the video signal is supplied from one signal input line. Is input, and the signal of the determination circuit that determines the auto focus mode by detecting the synchronizing signal from the video signal of this control signal is output to the switching circuit. An autofocus drive signal is output to a focus mechanism, and the focus mechanism is driven by an image signal detection method based on a video signal for shooting, and a focus lens is moved to perform automatic focusing.

On the other hand, when other focus operation is performed by remote operation or the like, a control signal by a focus drive signal is input from the signal input line, and the control signal does not have a synchronizing signal of a video signal, and the auto focus mode is set. The signal from the determination circuit that determines that it is not is output to the switching circuit, the switching circuit switches the drive signal for the focus mechanism, sends the focus drive signal to the focus mechanism, and drives the focus mechanism with this focus drive signal. Then, the focus lens is moved to a predetermined position.

As a result, a video signal or a focus drive signal for performing focus control can be input as a control signal from one signal input line.
The signal is determined to automatically switch between the autofocus operation and the remote focus operation, which simplifies by reducing the signal input line and does not require a switching signal for the switching circuit as an input control signal.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows a schematic overall configuration of a surveillance TV camera system including a lens driving device for a TV camera according to this embodiment.

The television camera 1 is composed of a camera body 2 and a lens unit 3, and the camera body 2 is a support base for a pan 4 which can pan in a turning direction and tilt in a vertical tilting direction.
It is supported by 4c. This platform 4 has a fixed leg 4a.
The platform main body 4b is installed on the platform 4, the platform base 4b is pivotally driven in the left-right direction with respect to the legs 4a, and the support base 4c is tilted vertically with respect to the platform base 4b. A servo mechanism (not shown) for driving the pan and tilt is installed in the platform body 4b.

On the other hand, the lens unit 3 of the TV camera 1
The drive unit 3a is equipped with a servo mechanism (not shown) for driving focus, zoom, iris, etc., and drives the focus mechanism by an image signal detection method based on a video signal being captured. An autofocus circuit 21, which will be described later, for automatically focusing is installed.

Further, a controller 6 (operation unit) is installed separately from the television camera 1 via the cable 5 so that remote control is possible, and a focus knob, a joystick, a zoom switch, and a speed adjusting section installed in the controller 6 are installed. Various command signals are sent to the television camera 1 and the platform 4 side based on the operation of the operator (cameraman) of the various operation members 7 such as
Signals such as video signals and confirmation signals are transmitted to the controller 6 from the television camera 1 and the platform 4 side, whereby the zoom, focus, iris and other operations of the television camera 1 and the pan 4 pan, The tilt operation and other controls can be performed.

Further, the controller 6 has a CRT 8
Is connected. An image based on a video signal taken by the television camera 1 is displayed on the CRT 8.
Further, the controller 6 is provided so as to be able to manually operate the television camera 1 and the platform 4, and to be able to perform a preset operation so as to perform a predetermined operation based on a command signal in which those operations are registered in advance. In particular, the focus operation is set so that the remote focus operation based on the manual operation and the preset operation can be performed in addition to the auto focus operation based on the video signal.

FIG. 1 is a block diagram of a focus driving system in a lens driving device for a television camera according to an embodiment of the present invention.

The television camera 1 comprises the camera body 2 and the lens unit 3 as described above.
A focus lens 11 that is movable in the optical axis direction is installed in the focus lens 11, and a focus motor 13 that is driven by a motor drive circuit 12 is linked to the focus lens 11 to move the focus lens 11 to a predetermined position.
Is provided.

On the other hand, in the camera body 2, the image formed on the CCD 15 as an image pickup device through the lens system of the lens unit 3 is converted into a video signal by the camera circuit 16, and the external controller 6 is provided by the signal output line 5b. Is sent to the control signal generating circuit 7. Further, the lens unit 3 is provided with a focus control section 20 for outputting a focus drive signal to the focus mechanism 10, and is composed of an autofocus circuit 21, a mode switching circuit 22, a video signal discriminating circuit 23, and a switching signal circuit 24. ing.

From the control signal generation circuit 7 of the controller 6, a control signal by either a video signal for autofocus operation or a focus drive signal for remote focus operation is supplied by one signal input line 5a. It is input to the camera body 2. The signal input line 5a and the signal output line 5b are connected by the cable 5. The control signal is input to the video signal discrimination circuit 23, the autofocus circuit 21, and the second input section IN2 of the mode switching circuit 22, respectively. Further, the output of the autofocus circuit 21 is input to the first input section IN1 of the mode switching circuit 22.

The video signal discriminating circuit 23 discriminates whether or not a video signal is input based on the presence / absence of a sync signal included in the video signal, that is, whether or not it is in the autofocus mode, and outputs a binarized signal. This determination signal is converted into a switching signal by the switching signal circuit 24. For example, a low level signal is output in the auto focus mode in which a video signal is input, and a high level signal is output in the remote focus mode. Signal to the mode switching circuit
It outputs to 22.

In the auto focus mode in which the low level signal is input, the mode switching circuit 22 outputs the signal (auto focus drive signal) input to the first input section IN1 to the motor drive circuit of the focus mechanism 10.
On the other hand, in the remote focus mode in which a high level signal is input, the second
The signal (focus drive signal) input to the input unit IN2 is sent to the motor drive circuit 12 of the focus mechanism 10.

The autofocus circuit 21 drives the focus lens 11 to a focus position corresponding to the position of the main subject being photographed by the image signal detection method based on the video signal of the control signal to perform automatic focusing. It outputs an autofocus drive signal, and is composed of, for example, an autofocus control circuit of a conventionally known hill climbing servo system.

In the hill climbing control, the high frequency component of the video signal is extracted and detected, and the focus voltage corresponding to this high frequency component corresponds to the definition of the photographed image. The control is based on the fact that the focus voltage becomes maximum and decreases as it deviates from this, and the lens position is controlled so as to climb the peak of the focus voltage and is positioned at the top of the peak where the focus voltage becomes maximum. is there. Specifically, the focus voltage is sampled and held at fixed intervals while moving the lens position by the motor, and if the focus voltage is in the increasing direction over time, the rotation direction of the motor is maintained and hill climbing continues, while in the decreasing direction. If so, the direction of rotation is reversed to return to the direction of climbing the mountain, and the focus is automatically adjusted by oscillating at the top of the mountain while reaching a steady state.

The focus drive signal output from the controller 6 is a signal having a voltage value corresponding to the target position of the focus lens 11, and the focus motor 13 is driven by the servo mechanism of the motor drive circuit 12 in the focus mechanism 10. Then, stop control is performed at the target position.

The operation of the above embodiment will be described. When performing the autofocus operation, the control signal generating circuit 7 of the controller 6 sends a video signal from the camera body 2 currently being photographed as a control signal. And is input to the lens unit 3 through the signal input line 5a. Upon receiving this control signal, the video signal discrimination circuit 23 discriminates from the detection of the synchronization signal that the video signal is input, that is, the autofocus mode, and the switching signal circuit 24 outputs a low level signal to the mode switching circuit 22. The mode switching circuit 22 sends the autofocus drive signal output from the autofocus circuit 21 to the motor drive circuit 12 by bringing the contacts on the autofocus side into conduction. The motor drive circuit 12 automatically focuses the position of the focus lens 11 to a position corresponding to the subject position of the captured image based on the autofocus drive signal.

On the other hand, when performing a remote focus operation, a focus drive signal based on a manual operation and a preset operation is sent as a control signal from the control signal generation circuit 7 of the controller 6, and the lens unit 3 is supplied through the signal input line 5a. Entered in. The video signal discriminating circuit 23 receiving this control signal discriminates the remote focus mode from the fact that the sync signal is not detected, and the high level signal is outputted from the switching signal circuit 24 to the mode switching circuit 22 to set the mode. The switching circuit 22 switches the contact on the remote focus side to be conductive and sends a control signal, that is, a focus drive signal to the motor drive circuit 12. The motor drive circuit 12 stops driving the position of the focus lens 11 to the instructed position based on this focus drive signal.

In the above embodiment, the video signal discriminating circuit 23 of the focus control section 20, the autofocus circuit 21 and the like are installed in the lens unit 3, but these should be built in the camera body 2. May be installed.

[0031]

As described above, according to the present invention, a discriminating circuit which receives an input control signal, discriminates whether a video signal is detected from the presence or absence of a synchronizing signal and discriminates whether or not it is in an autofocus mode, and the discriminating circuit. By providing a switching circuit that switches the drive signal to be sent to the focus mechanism based on the determination of, the video signal or the focus drive signal for performing focus control can be input as a control signal from one signal input line. It is possible to automatically switch between the auto focus operation and other focus operations by discriminating the signal, eliminating the need for a switching signal from the outside to the switching circuit and simplifying by reducing the signal input line. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a driving device for a television camera lens according to the present invention.

FIG. 2 is a schematic diagram showing an overall configuration of a surveillance TV camera system equipped with a lens driving device for a TV camera.

FIG. 3 is a block diagram showing a comparative example of a lens driving device for a television camera.

[Explanation of symbols]

 1 TV camera 2 Camera body 3 Lens unit 5 Cable 5a Signal input line 6 Controller 7 Control signal generation circuit 10 Focus mechanism 11 Focus lens 12 Motor drive circuit 13 Focus motor 15 CCD 20 Focus control unit 21 Auto focus circuit 22 Mode switching circuit 23 Video signal discrimination circuit 24 Switching signal circuit 25 Camera circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03B 13/34

Claims (1)

[Claims] 1. An autofocus circuit for driving a focus mechanism to perform automatic focusing by an image signal detection method based on a video signal being captured, and driving the focus mechanism by a separately input focus drive signal. In a device for driving a photographing lens for a television camera, a signal input line to which a control signal composed of the video signal or a focus drive signal is input, and the presence or absence of a synchronization signal included in the video signal when receiving the control signal A video signal discriminating circuit for discriminating whether or not it is in the autofocus mode, an autofocus drive signal by the autofocus circuit and the focus drive signal are inputted to an input section,
A lens driving device for a television camera, comprising: a switching circuit that switches a signal sent to the focus mechanism between the autofocus drive signal and the focus drive signal based on the determination of the determination circuit.