JPH04329077A - Video camera device - Google Patents

Abstract

PURPOSE:To make an electronic zooming function equal to an optical zooming without changing the distance measuring viewing angle of an auto focusing device even at the time of magnifying the screen due to the electronic zooming function by providing a gate circuit to be capable of switching equivalent to at least two types or above of the field angle of the image pick-up screen central part in the electronic zooming function and the auto focus function mounted on the video camera device. CONSTITUTION:At the usual time when an electronic zooming function is not operated, a wide angle gate circuit 9a is selected. Here, when an electronic zooming circuit 5 is operated, the electronic zooming information is sent from an electronic zooming circuit 5 to a control circuit 21. By the information, the control circuit 21 switches the gate in a gate circuit 9 from the wide angle gate circuit 9a through a selecting circuit 20 to a narrow angle gate circuit 9b.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera device having an autofocus function.

0002

2. Description of the Related Art In recent years, an autofocus function has become important in video camera devices from the viewpoint of improving operability. As a conventional technique, a high frequency component is detected by passing a video signal obtained from an image sensor through a BPF, and a focusing device of a lens is driven so that the level of this detection signal becomes maximum within one field or one frame. There is a method.

A conventional video camera device will be explained with reference to FIG. Reference numeral 1 denotes a lens with a focusing device, and this device is driven by a motor 12. 2 is an image sensor, 3 is a preamplifier that amplifies the output signal of the image sensor, 4 is a process circuit that converts it into a standard television signal, 5 is an electronic zoom circuit that electrically enlarges the center of the screen of the standard television signal, and 6 is a preamplifier that amplifies the image sensor output signal. 7 is a synchronous signal generator that generates a reference signal in the video camera device; 8 is a band pass filter (hereinafter referred to as BPF) that passes high frequency components of the video signal; 9 is a scanning drive circuit for the image sensor 2; A gate circuit that passes a signal corresponding to an arbitrary angle of view in the center of the screen of the video signal,
10 is a control circuit that controls the motor drive circuit 11 so that the output signal of the gate circuit 9 is maximized, and controls the motor 1.
Drive 2.

The operation of the conventional video camera device configured as described above will be explained using FIG. 3. FIG. 3 shows the peak output characteristics of the BPF 8 when the focus adjustment device is changed from a short distance to a long distance at the distance of the subject D1. Now, when the focus lens is adjusted to a shorter distance than D1, if the slight change in the lens 1 driven by the motor 12 is a1, then the change in the BPF peak output is b1. The output signal B1 is obtained by comparing the phases of these signals.
Move the focusing device in the direction of the arrow C1. Also, when the lens is adjusted to a distance longer than D1, the change in lens 1 is expressed as a2.
When doing this, the peak output signal of BPF8 changes as b2, so as a result of the phase comparison, B2 becomes the opposite polarity of B1, and the focusing device moves in the direction of the arrow C2, and as a result, the peak output signal of BPF8 becomes the maximum. It becomes stable at point D1, which becomes .

[0005]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional configuration, when an image is received by a TV device, etc., the imaged screen is enlarged by turning the electronic zoom function ON/OFF, but the signal input to the autofocus device does not change. This is equivalent to widening the range-finding angle of view of an autofocus device, which poses a problem in that it may lead to malfunctions during use or a decrease in operability.

The present invention solves the above-mentioned conventional problems, and automatically switches the distance measuring field of view of the autofocus device based on operation information of the electronic zoom function, thereby preventing malfunctions during use and improving operability. The purpose is to provide a camera device.

[0007]

[Means for Solving the Problems] In order to achieve this object, the video camera device of the present invention is capable of switching between at least two types of viewing angles that pass a signal corresponding to the center of the magnified screen by the electronic zoom function. The camera has a configuration that includes a gate circuit and a selection circuit for switching the gate circuit, and the gate circuit can be switched based on operation information of the electronic zoom function.

[0008]

[Operation] With this configuration, even when the image is received by a TV device, etc. by switching the gate circuit of the autofocus device by enlarging the imaging screen using the electronic zoom function, the electronic zoom can be performed without changing the field of view of the distance measurement of the autofocus device. It can be treated equivalently to optical zoom.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a lens equipped with a focusing device, and this device is driven by a motor 13. 2 is an image sensor, 3 is a preamplifier that amplifies the image sensor output signal,
4 is a process circuit for converting into a standard television signal; 5
6 is an electronic zoom circuit that electrically magnifies the central part of the screen of a standard television signal; 6 is a scanning drive circuit for the image sensor 2;
7 is a synchronizing signal generator that generates a reference signal in the video camera device, and 8 is a BP that passes high frequency components of the video signal.
F, 9 is a gate circuit that passes signals corresponding to multiple angles of view, 9a is a wide-angle gate circuit that passes signals corresponding to a wide angle of view, and 9b is a gate circuit that is narrower than the wide-angle gate circuit 9a. 9c is an analog switch that switches the output of each gate circuit, 2
0 is a selection circuit that selects the angle of view of the gate circuit 9, and 21 is a control circuit using a microcomputer or the like, which controls the motor drive circuit 11 and drives the motor 12 so that the output signal of the gate circuit 9 is maximized. .

The operation of the video camera device configured as described above will be explained. First, it is assumed that the wide-angle gate circuit 9a is selected in the normal mode in which the electronic zoom function is not operating. Here, electronic zoom circuit 5
When activated, electronic zoom information is sent from the electronic zoom circuit 5 to the control circuit 21. Based on this information, the control circuit 21 can switch the gate in the gate circuit 9 from the wide-angle gate circuit 9a to the narrow-angle gate circuit 9b through the selection circuit 20.

In the embodiment, the output of the preamplifier 3 is passed through the BPF 8 to the gate circuit 9, but it goes without saying that the output of the preamplifier 3 may be passed through the gate circuit 9 and then through the BPF 8.

[0013]

As described above, the present invention provides an electronic zoom function and a switchable gate circuit corresponding to at least two or more types of view angles at the center of the imaging screen in an autofocus device. This makes it possible to realize an excellent video camera device in which the distance measuring field angle of the autofocus device does not change even when the screen is enlarged, and the electronic zoom function can be made equivalent to optical zoom.

[Brief explanation of drawings]

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

[Figure 2] Block diagram of a conventional video camera device

[Figure 3]
B for explaining the operation of a conventional autofocus device
PF peak output level-level position characteristic diagram

[Explanation of symbols]

2 Imaging device 5 Electronic zoom circuit 8 Bandpass filter 9 Gate circuit 9a Wide angle gate circuit 9b Narrow angle gate circuit 20 Selection circuit 21 Control circuit

Claims (1)

[Claims] 1. Electronic zoom means for electrically enlarging a video signal obtained from an image sensor; a bandpass filter for passing high frequency components of the video signal; comprising: a gate circuit capable of switching between at least two types of angle of view through which a signal corresponding to the angle of view of the central part of the enlarged screen is passed; and a selection circuit for selecting the size of the angle of view of the gate circuit; It has an autofocus means for driving a focus lens so that the level of high frequency components of the video signal that has passed through the bandpass filter and the gate circuit is maximized,
A video camera device characterized in that, when the electronic zoom means is in operation, it controls the viewing angle of the gate circuit to be switched in accordance with the magnification rate of the electronic zoom means.