JPH07143389A - Camera - Google Patents

Abstract

PURPOSE:To provide a camera always stable in automatic focusing being and excellent in responsiveness, with automatic exposure control free from back light and excessive light, by allowing a detection area to track an object, and also, detecting a photographer's pan-tilt operation and controlling the tracking. CONSTITUTION:A video signal generated by a camera process circuit 4 is converted into motion information of an object and the whole screen by an area motion detecting means 11 and a scene motion detecting means 12, and based on this motion information, movement, stop and initialization of a tracking area are controlled by a tracking control part 13, it is converted into contrast information of the object by a focus signal detecting means 5, and based on this contrast information, a state of the object is decided by a lens control part 6 and a drive direction and a drive speed of a photographic lens 1 are determined, and automatic focusing is executed by a stepping motor 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera provided with an automatic tracking focus adjusting device or an automatic tracking exposure adjusting device, and more specifically, it quickly switches the tracking area to a target object intended by the photographer to perform focus adjustment and exposure adjustment. Regarding a camera that can be done.

[0002]

2. Description of the Related Art Regarding automatic focusing (AF), which is one of the basic functions of a video camera, various methods have been proposed and put into practical use. Among them, a method using a video signal (hereinafter referred to as a mountain climbing method). ) Is currently the mainstream method because it has advantages such as a smaller and lighter system. This hill-climbing method is described in detail in the article "Automatic focus adjustment of television cameras by hill-climbing servo method"("NHK Technical Research" Vol. 17, No. 1, page 21, 1965, Ishida et al.).

A high frequency component in the video signal which is a parameter of the hill climbing operation is detected as a focus signal from a set area (hereinafter referred to as a focus detection area) on the screen. Since it is generally considered that the subject intended by the photographer (hereinafter referred to as the main subject) is located at the center of the screen, the focus detection area is conventionally fixed at the center of the captured screen to detect the focus signal.

On the other hand, another basic function of the video camera, that is, automatic exposure control (ALC), is disclosed in JP-A-3-
As disclosed in Japanese Patent No. 238429, it is common to divide a screen into a plurality of parts, detect the distribution state of the luminance signal component of each screen, and perform ALC according to the state of backlight or over-forward light. .

[0005]

However, in AF, the photographer does not always photograph the main subject so as to be positioned at the center of the screen, and it is not desirable to impose such a constraint on the photographer. Also, even if the main subject is a moving object or the camera itself moves due to camera shake, etc., if the focus detection area is fixed, the main subject will be out of this focus detection area, or easily move in and out of the area. The focus signal fluctuates greatly each time, resulting in a malfunction of AF.

Further, in ALC as well, it is not possible to distinguish the subject intended by the photographer from the distribution state of the luminance component due to the screen division, and as a result, the ALC may not be properly exposed.

In view of the above point, the present invention provides a detection area for tracking a subject intended by the photographer, and further controls the detection area so as to track the subject even when the photographer switches the main subject. Accurately determine whether the camera shake, pan / tilt, or movement of the subject, control the tracking area based on that determination, and perform focus adjustment and exposure adjustment based on the focus signal and luminance information detected from within the tracking area. The purpose is to provide a camera.

[0008]

In order to achieve the above object, a camera provided with an automatic focusing device of the present invention comprises a taking lens including a focusing lens having a focus adjusting function,
An image pickup means for photoelectrically converting an optical image formed through a taking lens to output an electric signal, a camera process circuit for processing the electric signal and outputting a video signal, and the video signal for processing a set area in a shooting screen. Gate control means for defining the setting area, focus signal detecting means for detecting a focus signal by extracting a frequency component of a predetermined value or more in the first setting area defined in the video signal, and the focus signal A lens control unit that detects the focus state of the subject based on the detection result and outputs a control signal that drives the focus adjustment lens according to the detection result, and a lens drive that drives the focus adjustment lens based on this control signal to adjust the focus Means and a region motion detecting means for processing a signal in the second setting region of the video signal and detecting a region motion vector indicating a moving direction and a moving amount of a subject in the region. , A scene motion detecting means for processing a signal in the third setting area of the video signal and detecting a scene motion vector indicating a moving direction and a moving amount of the entire photographing screen, and a scene motion detecting means according to the area motion vector and the scene motion vector. The tracking control means is provided for determining whether to update, hold or initialize the second setting area, and to output the movement direction and the movement amount or the initialization signal to the gate control means based on the determination result.

Further, a camera provided with the automatic exposure adjusting device of the present invention comprises a taking lens, an image pickup means for photoelectrically converting an optical image formed through the taking lens, and a light quantity for adjusting the light quantity incident on the image pickup means. Adjusting means, a camera process circuit for processing an electric signal output from the image pickup means and outputting a video signal, a gate control means for defining the setting area so as to process the video signal for the setting area in the photographing screen, and this gate A photometric means for detecting and outputting the brightness information in the first setting area defined by the control means, and a light quantity adjusting section for judging the exposure state based on the brightness information and outputting a control signal for controlling the drive of the light quantity adjusting means. A control unit, a light amount adjusting unit driving unit that drives the light amount adjusting unit based on the control signal, and a signal in the second setting area of the video signal are processed to move the object in the area. A region motion detecting means for detecting a region motion vector indicating the direction and the amount of movement, and a signal in the third set region of the video signal are processed to detect a scene motion vector indicating the moving direction and the amount of movement of the entire photographing screen. A scene motion detecting means and a judgment of updating, holding or initialization of the second set area according to the area motion vector and the scene motion vector, and gate control of the moving direction and the moving amount or the initialization signal based on the judgment result. And tracking control means for outputting to the means.

[0010]

With the above construction, the tracking control means compares the output of the area motion detection means with the output of the scene motion detection means,
If the movement of the subject is determined using the difference in the direction of the motion vector and the size of each vector as a parameter, and if it is determined that the camera is panning / tilting, the tracking area is returned to the initial position so that The focus information and the brightness information of the intended subject are detected.

[0011]

Embodiments of the camera according to the present invention will be described below with reference to the drawings. First, as a first embodiment, an embodiment of a camera equipped with an automatic tracking focus adjustment device will be described. FIG. 1 is a configuration diagram of a main part of an embodiment of a camera of the present invention.

In FIG. 1, reference numeral 1 designates a zoom lens as a photographing lens. The zoom lens 1 is composed of four lens groups (each lens group is composed of one convex lens or one concave lens for the sake of convenience.
In 1) to 1d). The image of the subject 2 is input to the image sensor (for example, CCD) 3 via the zoom lens 1. The camera process circuit 4 performs various signal processing on the electric signal obtained from the image pickup device 3 and outputs a predetermined video signal (for example, NTSC signal) C _O.

The focus signal detecting means 5 outputs a focus signal V _F corresponding to the focus state of the zoom lens 1 from the luminance signal Y output from the camera process circuit 4 within the focus detection area set by the gate control unit 10. Calculate in cycles,
Output.

The lens control unit 6 determines the in-focus state of the zoom lens 1 based on the time variation and the absolute value of the focus signal V _F output by the focus signal detection unit 5, and causes the lens drive unit 7 to drive the stepping motor 8 at the drive speed. And a clock signal CK for defining the driving direction and a forward / reverse signal REV. The lens driving unit 7 drives the stepping motor 8 based on the clock signal CK and the forward / reverse rotation signal REV, and the stepping motor 8 causes the zoom lens 1 via the transmission mechanism 9.
The first lens group 1a is moved to a predetermined position, and automatic focus adjustment is executed.

The above is the description of the AF operation based on the basic hill climbing control. Next, how to track the focus signal detection area to the subject intended by the photographer will be described.

A tracking area having the same center position as that of the focus signal detection area is set by the gate control section 10, and the area motion detecting means 11 sets a luminance signal Y output from the camera process circuit 4 for an object in this tracking area. If necessary, the color difference signals (RY) and (BY) are processed, and the motion vector in the area is extracted by taking the frame difference, for example. On the other hand, in the scene motion detection means 12, for example, as shown in FIG.
The motion of the entire screen (information on camera operation such as camera shake and pan / tilt) is detected by representative point matching as shown in.

That is, in FIG. 3, the scene motion detecting means 12 performs the optimum band limitation for the motion information extraction by the filter 31 on the luminance signal Y output from the camera process circuit 4, and in the motion information detecting area. The signal amount P _F of each detection point is sent to the representative point matching calculation unit 32. The representative point matching calculation unit 32 receives the signal amount at the representative point, which is the base point for detecting the motion stored in the previous field or earlier, from the representative point memory unit 33, and receives the signal amount at each detection point in the detection area. Difference P with
_A is calculated.

The calculation result is sent to the microcomputer 34, and the relative position from the representative point of the detection point having the minimum difference value in the calculation result is output as the motion vector VS from the scene motion detection means 12 and is tracked. It is sent to the control unit 13. In this case, the motion vector VS is a parameter that represents the amount and direction of movement of the subject. At the same time, the microcomputer 34 sends the signal amount D _A of the representative point for performing the difference calculation of the next field to the representative point memory unit 33.

In the tracking control unit 13, the area motion detecting means 11
Motion vector VR of the subject in the tracking area output from
And the motion vector VS of the entire screen output from the scene motion detection means 12, the following determination is performed, and the gate control unit 10 is moved to the initialization signal RST for returning the tracking region to the initial position or the tracking region. A movement vector MV indicating the direction and the amount is output. (1) If the magnitude of the difference between VR and VS is less than or equal to the first set value, and if the duration of the magnitude of VR and VS exceeds the second set value continues for a specified time, an initialization signal is output. (2) VR If the magnitude of the difference between V and VS exceeds the first set value, the regional motion vector MV is output with MV = VR. (3) Other than (1) and (2) The movement vector MV is output with MV = 0 Gate control unit In 10, when the initialization signal RST is input, the tracking area is set to the initial position, for example, the central portion of the screen, and in other cases, the tracking area is moved or held based on the movement vector MV and the object is tracked. .

Here, in the case of (1), the first set value, the second set value, and the specified time are set so that it is detected that the photographer performs the pan / tilt operation to switch the main subject. Is set. As a result, the pan / tilt operation of the photographer can be detected, and the tracking area can be automatically returned to the central portion of the photographing screen to smoothly switch the main subject.

Further, the gate control unit 10 is set so as to move the focus signal detection area in conjunction with the position of the tracking area, and the focus signal detection means 5 always operates the focus signal V _F within the focus detection area where the main subject exists. Is detected, and the hill climbing control described above is performed based on the detected signal, so that stable and responsive AF operation is always possible.

In the above embodiment, the zoom lens 1
Although the lens group 1a used for the focus adjustment is not limited to this, the lens groups 1b to 1 used in a zoom lens generally called an inner focus system are used.
You may use d for focus adjustment. In this case, the light lens group is driven, and the high speed of AF is further increased.

Next, as a second embodiment, an embodiment of a camera provided with an automatic tracking exposure adjusting device will be described. 2 is a configuration diagram of a main part of an embodiment of a camera of the present invention.
The same parts as q are given the same q numbers.

In FIG. 2, the light of the subject 2 is formed as an optical image on the image pickup device (for example, CCD) 3 by adjusting the amount of light passing through the photographing lens 21 and further by the diaphragm 22. The image sensor 3 performs photoelectric conversion and amplification as in the first embodiment, and outputs a time series signal to the camera process circuit 4. The camera process circuit 4 performs synchronous synthesis, modulation and correction processing on the electric signal output from the image sensor 3,
A predetermined video signal, for example, NTSC signal Co is generated.

The photometry means 23 calculates the average brightness value YA of the brightness signal Y output from the camera process circuit 4 within the photometry area defined by the gate control section 8, and the aperture control section 24.
Output to.

The aperture control unit 24 outputs a control signal for changing the open / closed state of the aperture according to the average luminance value YA output from the photometry unit 23, and the aperture drive unit 25 outputs the aperture according to the control signal from the aperture control unit 24. Is controlled to adjust the amount of light incident on the image sensor 3.

The above is the basic exposure adjustment. By performing the same tracking control as in the first embodiment and associating the photometric area with the tracking area, the main subject can always be photometered, and even when the photographer switches the subject, the photometric area can be smoothly changed. Can be moved to a new subject. As a result, it is possible to always obtain an image with proper exposure, without the need for the conventional judgment of backlight and over-forward light and the correction based on it.

[0028]

As described above, according to the present invention, the area motion detection circuit and the scene motion detection circuit are provided, and the main subject is tracked and the main subject is switched according to the relationship between the detected motion vectors, so that the photographing is always performed. It is possible to obtain an image with proper exposure that is suitable for a subject intended by a person and is free of backlight or over-exposure.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of a camera having an automatic focus adjustment device according to the present invention.

FIG. 2 is a configuration diagram of a main part of an embodiment of a camera having an automatic exposure adjustment device according to the present invention.

FIG. 3 is a configuration diagram of a scene motion detection unit that extracts the motion of the entire screen.

[Explanation of symbols]

 1 Photographic lens (zoom lens) 2 Subject 3 Solid-state imaging device (CCD) 4 Camera process circuit 5 Focus signal detection circuit 6 Lens control unit 7 Lens drive unit 8 Stepping motor 9 Transmission mechanism 10 Gate control unit 11 Area motion detection unit 12 Scene Motion detection means 13 Tracking control section 21 Photographing lens 22 Aperture 23 Photometric means 24 Aperture control section 25 Aperture drive section 31 Filter 32 Representative point matching calculation section 33 Representative point memory section 34 Microcomputer

Claims (4)

[Claims] 1. A taking lens including a focus adjusting lens having a focus adjusting function, an imaging means for photoelectrically converting an optical image formed through the taking lens and outputting an electric signal, and the imaging means for outputting. A camera process circuit for subjecting the electric signal to signal processing and outputting a video signal; and a gate control means for defining the setting region so that the video signal output by the camera process circuit is processed for a setting region in a photographing screen. Of the video signal output from the camera process circuit, the frequency component having a predetermined value or more in the first setting area defined by the gate control means is extracted to correspond to the degree of contrast of the subject in the first setting area. Focus signal detecting means for detecting a focus signal to be generated, and a focus signal of the subject in the first setting area based on the focus signal output from the focus signal detecting means. A lens control unit that detects a focus state and outputs a control signal for driving the focus adjustment lens according to the detection result, and drives the focus adjustment lens based on the control signal output by the lens control unit. A lens driving unit that adjusts the focus and a signal within the second setting region defined by the gate control unit out of the video signals output by the camera process circuit are processed to move the object in the second setting region. And a region motion detection means for detecting a region motion vector indicating a movement amount, and a signal within the third setting region defined by the gate control means out of the video signals output by the camera process circuit, to process the entire photographing screen. Scene motion detecting means for detecting a scene motion vector indicating the moving direction and moving amount of the area motion vector, and the area motion vector output by the area motion detecting means It is determined whether to update, hold or initialize the second setting area according to the scene motion vector output by the scene motion detection means, and based on the result of the determination, the moving direction and the moving amount or the initialization signal is output to the gate. Tracking control means for outputting to the control means, the gate control means sets the second setting area based on the movement direction and movement amount or the initialization signal output by the tracking control means, and A camera having an automatic tracking focus adjustment device, wherein the first setting area is set according to the position of the second setting area. 2. A photographic lens, an image pickup means for photoelectrically converting an optical image formed through the photographic lens and outputting an electric signal, and a light quantity adjustment for adjusting the amount of light incident on the image pickup means through the photographic lens. Means, a camera process circuit for performing signal processing on the electric signal output by the image pickup means to output a video signal, and the setting for processing the video signal output by the camera process circuit for a set region in a shooting screen. A gate control means for defining an area; a photometric means for detecting and outputting luminance information in the first setting area defined by the gate control means in the video signal output by the camera process circuit; and the photometric means. A light amount adjusting section control that determines an exposure state in the first setting area based on the output brightness information and outputs a control signal for controlling the driving of the light amount adjusting means. Means, a light quantity adjusting section driving means for driving the light quantity adjusting means based on the control signal outputted by the light quantity adjusting section control means, and the gate control means among the video signals outputted by the camera process circuit. Area motion detection means for processing a signal in the second setting area and detecting an area motion vector indicating a moving direction and a moving amount of a subject in the second setting area, and the video signal output from the camera process circuit. Of these, the scene motion detecting means for processing a signal in the third setting area defined by the gate control means and detecting a scene motion vector indicating the moving direction and the moving amount of the entire photographing screen, and the area motion detecting means output the same. Update or hold of the second set area according to the area motion vector and the scene motion vector output by the scene motion detection means. Or tracking control means for performing initialization determination and outputting a movement direction and a movement amount or an initialization signal to the gate control means based on the determination result, wherein the gate control means outputs the tracking control means. Automatic tracking, characterized in that the second setting area is set based on the moving direction and the moving amount or the initialization signal, and the first setting area is set according to the position of the second setting area. A camera with an exposure adjustment device. 3. The tracking control means, when the magnitude of the difference between the regional motion vector and the scene motion vector exceeds a first set value, changes the direction and the magnitude of the regional motion vector so as to update the second set region. 3. The camera according to claim 1, wherein the movement amount is output to the gate control means. 4. The tracking control means, when the magnitude of the difference between the regional motion vector and the scene motion vector is within the first set value and the magnitude of each vector exceeds the second set value for a certain period of time. The camera according to claim 1 or 2, wherein an initialization signal is output to the gate control means so as to return the second setting area to the initial position.