JPH02272986A - Video camera - Google Patents

Abstract

PURPOSE:To simplify a camera operation by detecting the fact that a chrominance signal from an image pickup element is only a red signal at the time of an infrared image pickup and automatically taking off an infrared ray blocking filter from the optical path of the image pickup element at the time of the sharing use for a color image pickup and the infrared image pickup. CONSTITUTION:The fact that the image pickup signals of image pickup elements 7R, 7G and 7B are only a red signal R is detected from outputs of a logical circuit 11 and a detecting circuit 10R, an infrared mode is decided at such a time, and an infrared mode signal is transmitted. A filter driving unit 5 is driven, and an angle position on the incident optical path of the image pickup element of a filter disk 3 is automatically made into a condition in which filters 4a-4c having infrared ray blocking functions do not exist, namely, a condition in which a through hole 3b of passing by is positioned. Thus, a necessity for a user to manually execute a changeover by discriminating the infrared image pickup mode or color image pickup mode can be eliminated, and the operability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video camera that functions as both a color camera and an infrared camera, and particularly relates to a video camera that automatically switches according to each imaging mode.

[Summary of the Invention] The present invention is a video camera used for both color imaging and infrared imaging, which detects that the color signal from the imaging probe is only a red signal during infrared imaging, and automatically activates the infrared blocking filter. This simplifies camera operation by removing the camera from the optical path of the image sensor.

[Prior Art] Traditionally, video cameras have been capable of capturing color images using normal visible light and capturing black and white images using infrared light.
A dual-purpose type that uses a stand-alone camera is known. This conventional color mode/infrared mode video camera places an infrared blocking filter on the incident optical path of the image sensor when capturing images in color mode, and removes this infrared blocking filter from the optical path when capturing images in infrared mode. We are planning to remove it so that it can be shared. Infrared blocking filters include
For studio use, there are models with a color temperature correction function of 3200°, and for outdoor use, in addition to a color temperature correction function of 5600°K, there are also models equipped with an ND (neutral density) function to suppress the amount of light. . A switching mechanism for these filters is disclosed in Japanese Utility Model Application No. 57-23075. This is done by placing each filter on a disk and turning the filter disk with a knob.
This mechanism inserts the above-mentioned infrared blocking filter onto the optical path of the image sensor during daytime color imaging, and similarly removes the infrared blocking filter during infrared imaging at night.

In addition, for video cameras that require remote control,
As shown in the explanatory diagram of the conventional video camera in Fig. 3,
A filter drive unit 103 is attached to a knob 102 that rotates a filter disk 101 of a video camera 100, and this is connected to a wired remote controller 104.
It was operated manually and remotely.

[Problems to be Solved by the Invention] However, in conventional video cameras that can be used in both color mode and infrared mode, when switching between color mode and infrared mode, the imaging of the infrared blocking filter is difficult. Since insertion and removal of the element from the optical path is a manual operation, it has been desired to simplify the operation by eliminating the need for this operation.

The present invention has been devised to solve the above problems, and therefore provides a video camera that automates the switching of infrared blocking filters during color imaging and infrared imaging, and improves the operability of camera operation. With the goal.

[Means for Solving the Problems] The configuration of the video camera of the present invention to achieve the above object is as follows: A filter that blocks infrared rays is inserted into or removed from the incident optical path of the image sensor to perform color imaging and infrared imaging. In a video camera that selectively performs the above, means for detecting that the color signal output from the image sensor is only a red signal or that both a green signal and a blue signal are not detected;
It is characterized by comprising a driving means for moving the filter to the outside of the incident optical path of the image sensor when the detection is performed.

[Function] The present invention focuses on the fact that the color signal from the image sensor of the video camera during infrared imaging is only a red signal, and by detecting this, the infrared blocking filter is driven and automatically It is moved out of the incident optical path of the image sensor, and the mode is switched to infrared imaging mode.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an embodiment of a color mode/infrared mode video camera according to the present invention, and FIG. 2 is a block diagram of a filter disk.

The video camera of this embodiment is an example of a so-called three-plate video camera in which a CCD solid-state image sensor (hereinafter referred to as COD) is used for each color.

In FIG. 1, I indicates an imaging lens, and image light from a subject passes through this imaging lens l and enters a prism 6 via an optical low-pass filter 2 and a filter disk 3. In this case, the filter disk 3 is rotatable about a central axis 3a, and has four through holes 3b, 3c, 3d, and 3e arranged at 90° intervals, as shown in FIG. The filter disk 3 has one of the through holes 3b depending on the angular position.
3e are disposed between the optical low-pass filter 2 and the prism 6. Among these, the through hole 3b is transparent, and the through hole 3c
, 3d, and 3e include filters 4a and 4 with different characteristics, respectively.
Install b and 4c. These filters 4a to 4c include
In addition to having an infrared blocking function that blocks the transmission of infrared rays outside the visible range, for example, the filter 4a has a color temperature correction function of 3200°, and the filter 4b has a color temperature correction function of 6400°.
°ni no color iN! The filter 4c is provided with an L degree correction function, and the filter 4c is provided with a color temperature correction function of 7000 degrees, in preparation for various color imaging. The transparent through hole 3b is for infrared imaging. A gear transmission mechanism 3f is attached to the central shaft 3a of the filter disk 3, and is coupled to the rotating shaft of the filter drive unit 5 to determine the rotational angular position of the filter disk 3. For example, as shown in FIG. 2, the positioning is performed by appropriately providing a positioning notch 3g on the outer periphery of the filter disk 3 and detecting it with an optical sensor or microswitch, or by using an encoder. This can be done by known means such as

6 is a prism that performs color separation, and a filter disk 3
The image light incident on the prism 6 is separated into three primary colors of red image light, green image light, and blue image light and then emitted.

Note that the prism 6 of this embodiment is formed so as to transmit light having a wavelength in the infrared region as well as red image light. This prism 6 has a red color C0 close to its red image light emitting part.
D7R is installed, and a green CC is installed near the green image light emitting part.
D7G is placed, and a blue In
Place COD 7 B. These color imaging elements C0D7R, 7G, and 7B output imaging signals (red signal R, green signal G, blue signal B) according to the amount of incident light,
The signals are supplied to video amplifiers 9R, 9G, and 9B via preamplifiers 8R, 8G, and 8B, respectively. In the above, the video amplifier 9R for red signal R and the video amplifier 9B for blue signal B
In this case, the gain is adjusted by the control of the white balance adjustment circuit of the circuit.

Changeover switch! S WI, S W t, and detection circuits 10R and IOG for detecting each color signal RG and B.

10B, AND logic circuit 11, and selection signal output circuit 1
2 is a circuit that generates a selection signal (infrared mode signal, color mode signal) for controlling switching between color mode and infrared mode, which is a main part of this embodiment. The detection circuit 10R is connected to the output of the video amplifier 9R to detect the red signal R, the detection circuit 10G is connected to the video amplifier 9G to detect the green signal G, and the detection circuit 10B is connected to the output of the video amplifier 9R to detect the green signal G.
is connected to video amplifier 9B to detect blue signal B.

The output of the detection circuit 10B and IOC is, for example, a negative logic output (
When no color signal is detected, a high level is output) and input to the logic circuit 11. The logic circuit 11 selects a high level only when both the green signal G and the blue signal B are not detected as an AND logic of these inputs.
Output to 2.

A detection circuit 10R is also connected to the selection signal output circuit 12,
This detection circuit 10R detects the red signal R, and the logic circuit l! If it detects that the color signal is only the red signal R by detecting that the color signals G and H are not detected, the filter drive unit 5 transmits the infrared mode signal indicating the infrared mode. At the same time, it is also output to switches sw, , sw. In cases other than infrared mode, the selection signal output circuit 12 outputs a color mode signal. Of course, this signal may be an inverted signal of the infrared mode signal. If the output of the detection circuit 10B 1OG is set to positive logic, and the logic circuit 11 is set to NOR logic, a logic output equivalent to the above can be obtained. Upon receiving the infrared mode signal, the filter drive unit 5 positions the filter disk 3 angularly so that the transparent through hole 3 b is located between the optical low-pass filter 2 and the prism 6 . When the filter drive unit 5 receives a color mode signal, for example, the filter drive unit 5 outputs a preset filter 4.
Position any one of a to 4c. switch sw...
sw is the above infrared mode signal, and is connected from the C side input terminal ■
Switch to the input terminal. Switch SW1 is C
Connect the output of video amplifier 9G to the side input terminal, connect the output of video amplifier 9R to the side input terminal, and send out the amplified output of green signal G in color mode (C side) and infrared mode. At the time (■ side), the amplified output of the red signal R is input to the image enhancer 13a to perform vertical contour correction during infrared imaging. In addition, the switch SW is C
Connect the amplified output of the red signal R to the side input terminal, leave the ■ input terminal open (not connected), and use it in color mode (C
side), the amplified output of the red signal R is sent to the process processing circuit 13.
In addition, in the infrared mode (I side), the amplification output of the red signal R is not performed manually.

The process processing circuit 13 includes a circuit that performs signal processing such as flare correction, gamma correction, shading correction, etc. on the image signal, and matrixes the red signal R1 green signal G and blue signal B as imaging signals that have been subjected to these processes. The primary color signals R,
G and B are converted into a luminance signal Y and color difference signals RY and BY. The converted color difference signals R-Y and B-Y are supplied to an encoder 15, which converts them into multiplexed signals, and then supplies them to a mixing circuit 16. In this case, the encoder 15 is a selection signal output circuit! Color difference signal processing is performed only when a color mode signal is supplied from 2, and no color difference signal is output when an infrared mode signal is supplied. The luminance signal Y outputted from the above matrix circuit 14 is output from the mixing circuit 1.
6, the mixing circuit 16 mixes the luminance signal with the color difference signal, and supplies the mixed signal to the output terminal 17 as a predetermined combined video signal.

The operation of the embodiment configured as above will be described.

Infrared imaging is performed using an infrared floodlight at night or the like. Therefore, in this case, the image sensor 7R.

From 7G and 7B, only the red signal R is output as an imaging signal. During color imaging, such a situation may occur, and color signals of at least two colors are always output.

Of course, if you put a cap on the front of the optical system, all color signals will be absent even in color mode, but if you remove the cap to take an image, the above state will return, so There is little need to consider it. This embodiment utilizes the above-mentioned features to provide a logic circuit 11 and a detection circuit 1.
The filter detects from the output of 0R that the imaging signals of the imaging elements 7R, 7G, and 7B are only the red signal R, determines that the time is the infrared mode, and emits an infrared mode signal. By driving the drive unit 5, the angular position on the incident optical path of the image sensor of the filter disk 3 is automatically changed to the filters 4a, 4b, 4c having an infrared blocking function.
In other words, the transparent through hole 3b is positioned. At the same time, the circuit system also switches the connection of the red signal R to the circuit system that processes the green signal G in order to perform vertical contour correction on the red signal R.

In the above embodiment, the infrared mode signal is the red signal R.
is detected and both the green signal G and the blue signal B are not detected, but it is said that the green signal G
Even if the infrared mode signal is emitted when both the blue signal B and the blue signal B are not detected, similar switching can be achieved in practice.

As described above, the present invention can be applied in various ways in accordance with its gist, and can take on various forms of actual PM.

Ru.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the video camera of the present invention, FIG. 2 is a block diagram of a filter disk, and FIG. 3 is an explanatory diagram of a conventional video camera. 3... Filter disk, 3b... Clear through hole,
4 a, 4 b, 4 c...filter, 5... filter drive unit, 7R, 7G, 7B... image pickup device (COD), tort, toc, ton...
Detection circuit, 11... Logic circuit, 12... Selection signal output circuit, sw, , sw,... switch. [Effect of the invention]

Claims (1)

[Claims] (1) In a video camera that selectively performs color imaging and infrared imaging by inserting or removing a filter that blocks infrared rays from the incident optical path of the image sensor, the color signal output from the image sensor is only a red signal. and a drive means for moving the filter to the outside of the incident optical path of the image sensor when the detection is made. video camera.