JPH08205021A - Image input device - Google Patents

Abstract

PURPOSE: To receive an excellent image even when a large luminance level difference is in existence in an image. CONSTITUTION: An image information frame setting device 50 sets an image information frame used to acquire image pickup information used for exposure control and focus control to a camera system control circuit 38. The circuit 38 controls a gain, a shutter speed, an iris and a focus according to the image pickup information in the image frame. A motion detection circuit 36 detects the motion of an object in the set image information frame and transfers the motion to a computer 40 via the circuit 38. The computer 40 calculates the position of a new image information frame in following to the motion of an object and sets it to the circuit 38 via a setting device 50. Plural image information frames may be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device,
More specifically, the present invention relates to an image input device used for image input of conference participants and various materials in a communication system such as a video conference system and a video conference system.

[0002]

2. Description of the Related Art FIG. 3 shows a schematic block diagram of a conventional image input device. In FIG. 3, 110 is a lens unit, 112 is a solid-state image sensor, 114 is a signal processing circuit that processes the output signal of the solid-state image sensor 112 as an analog signal, and 116 is an analog signal output of the signal processing circuit 114 that is converted into a digital signal. A / D converter, 118 is a γ correction circuit that γ-corrects the output data of the A / D converter 116, 120 is a memory that stores the output data of the γ correction circuit 118, and 122 is image data read from the memory 120. Is an analog signal, and a digital interface 124 is for digitally outputting the image data read from the memory 120.

Reference numeral 126 is a shutter speed control circuit for controlling a shutter speed of a shutter provided in the lens unit 110, 128 is an iris control circuit for controlling an iris provided in the lens unit 110, and 130 is writing and reading in the memory 120. Is a memory control circuit for controlling.

The operation of the conventional example having such a configuration will be briefly described. The shutter speed control circuit 126 and the iris control circuit 128 set the shutter speed and the iris of the shutter provided in the lens unit 10 to appropriate values according to the average brightness level of the captured image (for example, the output of the signal processing circuit 114). To control. An optical image of the subject is formed on the photoelectric conversion surface of the solid-state image sensor 112 by the lens unit 110, and the image sensor 112 outputs an electric signal of the optical image. The signal processing circuit 114 adjusts the clamp, black level, blanking and gain of the output signal of the image sensor 112. The A / D converter 116 is the signal processing circuit 1
The analog output of 14 is converted into a digital signal, and the γ correction circuit 118 γ-corrects the output data of the A / D converter 116.

The output data of the γ correction circuit 118 is written in the memory 120 under the control of the memory control circuit 130 and is read at a predetermined timing. The data read from the memory 120 is applied to the D / A converter 122 and the digital interface 124, and is output as an analog signal and a digital signal, respectively.

[0006]

In the conventional image input device, the shutter speed control circuit 126, the iris control circuit 128, and the signal processing circuit 114 are respectively provided in this manner in accordance with the brightness level and the state of the entire captured image. , Shutter speed, aperture value and gain are controlled.

In the case of a subject having no large difference in brightness level on the screen, a good image can be input without much problem. However, if the brightness level difference on the screen is large,
For example, when shooting a subject against a window in a room in the daytime, the average brightness level on the screen becomes extremely high, so the subject and the shadowed part of the subject are black. It causes crushing. In such a case, an image quality improvement is attempted by image processing such as backlight correction, but depending on the photometric region and the correction method, a great effect cannot be obtained, and it is still difficult to discriminate the subject.

Also, when the main subject is not in the center of the screen, the background other than the subject may be in focus depending on how the distance measuring frame is taken, which also causes a difficulty in identifying the subject. .

In these states, conventionally, the position of the camera is changed, the person as the subject moves to a position where a good screen is obtained, or the background is darkened.

However, such measures may be very troublesome or practically impossible. For example, in a video conference or a video conference, such measures are not only very troublesome, but may not be possible depending on the equipment installation situation.

It is an object of the present invention to provide an image input device capable of inputting a good image even when there is a large brightness level difference on the screen.

It is another object of the present invention to provide an image input device which does not cause blackout and / or whiteout of a subject portion as much as possible.

Another object of the present invention is to provide an image input device suitable for image input of a video conference or a video conference.

Further, according to the present invention, shooting conditions (focus, focus,
It is intended to provide an image input device for controlling exposure, gain, etc.).

A further object of the present invention is to provide an image input device for making such an image information frame follow a subject.

[0016]

An image input apparatus according to the present invention comprises an image pickup means for converting an optical image into an electric signal, and an image for setting at least one image information frame within the screen of the image picked up by the image pickup means. According to the information frame setting means, the motion detecting means for detecting the movement of the subject in the image information frame set by the image information frame setting means, and the captured image in the image information frame set by the image information frame setting means. It is characterized by comprising image quality adjusting means for adjusting the image quality, and image information frame storage means for storing position information of one or more image information frames set by the image information frame setting means.

The image quality adjusting means comprises one or more of a shutter speed control means for changing the shutter speed, an iris control means for controlling the diaphragm, and a gain control means for controlling the gain.

Further, there is provided system control means for controlling the image information frame setting means, the image quality adjusting means, the image information frame storing means and the motion detecting means in accordance with an external control signal.

Further, the image information frame display means for displaying the image information frame set by the image information frame setting means to the operator is provided.

Further, there is provided image information frame updating means for updating the corresponding image information frame according to the detection result of the motion detecting means.

[0021]

By the above means, the image information frame for obtaining the information necessary for adjusting the focus and the image quality can be arbitrarily set within the photographing screen. Thus, even if there is a large brightness difference in the screen, the subject is not in the center, or there are multiple subjects, it is possible to properly focus on the desired subject and control the exposure to an appropriate value. Further, by tracking the image information frame to the subject, even if the subject moves, it is possible to focus and control the exposure to an appropriate value without any trouble.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic block diagram of an embodiment of the present invention. In FIG. 1, 10 is a lens unit, 12 is a solid-state image sensor, 14 is a signal processing circuit for analog signal processing the output signal of the solid-state image sensor 12, and 16 is
An A / D converter for converting the analog signal output of the signal processing circuit 14 into a digital signal, and 18 for the A / D converter 1
6, a γ correction circuit for γ correcting the output data of 6, a memory for storing the output data of the γ correction circuit 18, a 22 for a D / A converter for converting the image data read from the memory 20 into an analog signal, 24 Is a digital interface for digitally outputting the image data read from the memory 20.

Reference numeral 25 is a gain control circuit for controlling the gain in the signal processing circuit 14, and 26 is the lens unit 1.
0 is a shutter speed control circuit for controlling the shutter speed of the shutter, 28 is an iris control circuit for controlling the iris provided in the lens unit 10, 30 is a zoom control circuit for controlling the magnification of the lens unit 10,
A focus control circuit 32 controls the focus of the lens unit 10.

Reference numeral 34 is a memory control circuit for controlling the writing and reading of the memory 20, 36 is a motion detection circuit for detecting the motion of the subject within the designated image information frame, and 38 is
According to the control signal from the computer 40, the control circuit 2
This is a camera system control circuit that totally controls each part via 5, 26, 28, 30, 32, and 34.

The computer 40 has a D / A converter 2
Two output signals are supplied, and video is displayed on the screen of the monitor 42 to be connected. Computer 44
Is a system control unit 44 that controls the whole, an image information frame display unit 46 that displays an image information frame whose details will be described later on the screen of the monitor 42, and a display switching unit that switches whether to display the image information frame. It is equipped with.

A camera system control circuit 3 50 interprets image frame information data from the computer 40.
8 is an image information frame setting device that transfers and sets the image information frame.

The operation of the above embodiment will be described. In the normal mode or state, the shutter speed control circuit 26 and the iris control circuit 28 respectively respond to the average brightness level of the captured image (for example, the output of the signal processing circuit 14).
The gain control circuit 2 controls the shutter speed and iris of the shutter provided in the lens unit 10 to appropriate values.
5 controls the gain. An optical image of a subject is formed on the photoelectric conversion surface of the solid-state image sensor 12 by the lens unit 10, and the image sensor 12 outputs an electric signal of the optical image.
The signal processing circuit 14 adjusts the clamp, black level, blanking and gain of the output signal of the image sensor 12. A
The / D converter 16 converts the analog output of the signal processing circuit 14 into a digital signal, and the γ correction circuit 18 performs γ correction so that the output data of the A / D converter 16 can be expressed accurately on the monitor screen.

The output data of the γ correction circuit 18 is written in the memory 20 under the control of the memory control circuit 34, and read out at a predetermined timing. The data read from the memory 20 is stored in the D / A converter 22 and the digital
It is applied to the interface 24, and an analog output and a digital output are made by each. D / A converter 2
The output of No. 2 is applied to the monitor 42 via the computer 40 and displayed as an image on the screen.

The system operator uses the system control computer 40 to obtain an image according to the purpose while looking at the image displayed on the monitor 42.
In addition to sending a control command to the system control circuit 38 to finely adjust the shooting condition, the operation can be performed in a mode for controlling the shooting condition according to the shooting information in the image information frame as described below.

Here, consider a case where the brightness level difference on the screen is large, for example, a case where a person is photographed against a window during the day. In such a situation, the areas other than the subject become brighter and the average value of the brightness level of the entire screen becomes higher.Under normal exposure control, areas with low brightness levels, such as the subject, will appear underexposed. (For example, facial expression) cannot be identified. Such a situation is inappropriate for video communication. If the metering frame and the distance measuring frame are sufficiently smaller than the subject, you can obtain the proper exposure and the in-focus state by aligning the metering frame and the distance measuring frame with the subject. However, if the size is inappropriate compared to the subject, a good image cannot be obtained. In this embodiment, even in such a case, a good image can be obtained as follows.

That is, the operator operates the computer 40 to display the image information frame by the frame display switching unit 48, and positions the image information frame so that the desired subject enters the image information frame. The position data of the image information frame is supplied to the image information frame setting device 50, and the image information frame setting device 50 instructs the camera / system control circuit 38 to set the image information frame at the specified position.

The camera / system control circuit 38 calculates control parameters from the photographed image information in the newly set image information frame, and the gain control circuit 2 according to the calculation result.
5. The gain, shutter speed and aperture value are controlled via the shutter control circuit 26 and the iris control circuit 28. Further, the camera / system control circuit 38 supplies the position information of the newly set image information frame to the motion detection circuit 36,
The motion detection circuit 36 detects a motion amount and a direction within the image information frame according to the image information frame designated by the camera / system control circuit 38. The detected motion amount and direction are transferred to the control computer 40 via the camera / system control circuit 38.

The control computer 40, based on the motion detection result, that is, according to the motion of the subject in the image information frame,
The moving direction and the distance of the new image information frame are calculated. The information of the calculated new image information frame is the image information frame setting device 5
0 to the camera system control circuit 38. In this way, the image information frame moves from the position initially specified, following the movement of the subject. Since the photographing condition is determined by the photographed image in the image information frame, it is possible to continue the photographing in which the subject is exposed and focused while following the initially set subject.

Although the shutter speed, the iris, and the gain are used as the image quality adjustment factors in the above embodiment, the present invention is not limited to this. As the image quality adjustment element, these parts or other elements may be included.

Further, in the above embodiment, one image information frame can be set, but a plurality of image information frames can be set and the shooting conditions are automatically set based on the image information obtained from the plurality of image information frames. Can be modified to control. For example, it is effective when there are a plurality of subjects on the screen and there is depth in the shooting screen. A modified embodiment thus configured will be described with reference to FIG. FIG. 2 shows a schematic block diagram of the modified embodiment. The same components as those in FIG. 1 are designated by the same reference numerals. Reference numeral 60 is an image information frame storage device that stores position information of a plurality of image information frames, and 62 is an image information frame storage device 60
Is always referred to, a plurality of image information frames according to a plurality of image information frame position information stored therein are set on a photographing screen, and each unit is controlled by the photographing information inside thereof.

Since the basic operation is the same as that of the embodiment shown in FIG. 1, different points will be mainly described. The embodiment shown in FIG. 2 is useful when a plurality of subjects are located at different distances in a depth scene, as described above.
It is also useful when the subject is not in the center of the screen from the beginning and is further away from the background.

In such a case, the operator sets the image information frame to the display state by the frame display switching 48 and sets the image information frame for each subject. The position information of the set plurality of image information frames is sequentially transferred to the camera / system control circuit 62 via the image information frame setting device 50, and the camera / system control circuit 62 determines the positions of the plurality of input image information frames. The information is stored in the image information frame storage device 60, and the image information frame is set at each position for controlling the shooting condition, and the focus, iris, gain and the like are controlled by the shot image in the image information frame. Thereby, even when a plurality of subjects are present in one screen and it is necessary to focus on each subject, it is possible to focus on each subject as a whole and control the exposure to an appropriate value.

If necessary, similar to the embodiment shown in FIG.
The image information frame is made to follow the movement of the subject. The position information of the new image information frame when the camera / system control circuit 62 distinguishes the image information frame by a serial number or the like so as not to be mistaken for the setting of the new image information frame,
A corresponding serial number may be added and transferred to the camera / system control circuit 62. The camera / system control circuit 62 uses the same serial number for the image information frame storage device 60.
The position information stored in is updated with new position information.

Normally, the image information frame is used as the distance measuring frame and the light measuring frame, or a measuring frame that also serves as the distance measuring frame and the light measuring frame is set inside the image information frame. In some cases, it may be possible to obtain a more appropriate image by using different photometric frames. In preparation for such a case, it is desirable to be able to arbitrarily select whether or not the photometry frame and the distance measurement frame are the same.

In the embodiment shown in FIG. 2, since an arbitrary number of image information frames can be set in an arbitrary size, the exposure can be controlled by focusing on an arbitrary number of subjects at arbitrary positions.

Also in the embodiment shown in FIG. 2, the shutter speed, the iris and the gain are used as the image quality adjusting elements, but the present invention is not limited to this. As the image quality adjustment element, these parts or other elements may be included.

[0043]

As described above, according to the present invention, since the image information for controlling the photographing condition can be limited to the image information in the image information frame which can be set arbitrarily, there is a large brightness difference in the screen. Even if the subject is not in the center or there are multiple subjects, it is possible to properly focus and control the exposure to an appropriate value. Further, by tracking the image information frame on the subject, even if the subject moves, the subject can be focused and the exposure can be controlled to an appropriate value without any trouble.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an embodiment of the present invention.

FIG. 2 is a schematic block diagram of a modified embodiment.

FIG. 3 is a schematic block diagram of a conventional image input device.

[Explanation of symbols]

 10: lens unit 12: solid-state image sensor 14: analog circuit 16: A / D converter 18: γ correction circuit 20: memory 22: D / A converter 24: digital interface 25: gain control circuit 26: shutter speed control circuit 28: Iris control circuit 30: Zoom control circuit 32: Focus control circuit 34: Memory control circuit 36: Motion detection circuit 38: Camera / system control circuit 40: System control computer 42: Monitor 44: System control unit 46: Image information Frame display unit 48: Display switching unit 50: Image information frame setting device 60: Image information frame storage device 62: Camera / system control circuit 110: Lens unit 112: Imaging element 114: Analog circuit 116: A / D converter 118: γ correction circuit 120: memory 122: D / A converter 124: Digital interface 126: Shutter speed control circuit 128: Iris control circuit 130: Memory control circuit

Claims (7)

[Claims] 1. An image pickup means for converting an optical image into an electric signal, an image information frame setting means for setting at least one image information frame within a screen of a captured image by the image pickup means, and the image information frame setting means. Motion detection means for detecting the movement of the subject in the set image information frame, image quality adjustment means for adjusting the image quality according to the captured image in the image information frame set by the image information frame setting means, and the image information frame An image input device, comprising: image information frame storage means for storing position information of one or more image information frames set by the setting means. 2. The image input device according to claim 1, wherein the image quality adjusting means comprises shutter speed control means for changing a shutter speed. 3. The image input device according to claim 1, wherein the image quality adjusting means comprises an iris control means for controlling an aperture. 4. The image input device according to claim 1, wherein the image quality adjustment means includes a gain control means for controlling a gain. 5. The system control means for controlling the image information frame setting means, the image quality adjusting means, the image information frame storing means and the motion detecting means according to an external control signal. The image input device according to any one of claims. 6. The image input device according to claim 1, further comprising image information frame display means for displaying an image information frame set by the image information frame setting means to an operator. . 7. The image input device according to claim 1, further comprising image information frame updating means for updating the corresponding image information frame according to the detection result of the motion detecting means.