JPH07203280A - Controller for image blur detection - Google Patents

Abstract

(57) [Abstract] [Purpose] In an electronic image stabilization system, it is possible to perform accurate image blur prevention even during zooming. [Structure] By changing the position of a camera shake detection area and the position of a representative point in this area according to a change in the angle of view of an image output from a camera, camera shake during zooming is detected, and image stabilization control is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device such as a camera or a video camera having a function of preventing image blur caused by camera shake.

[0002]

2. Description of the Related Art Conventionally, there are the following types of optical systems having a camera shake correction function (anti-vibration function). 1. A method in which the entire optical system and imaging system are movably supported by a gimbal mechanism, and even if camera shake occurs, the entire optical system and imaging system are fixed in space to eliminate image blur caused by camera shake. The mechanism of 2.1 is further provided with camera shake detection means such as an acceleration sensor and an angular acceleration sensor, and drive means for driving a unit composed of an movably supported optical system and an imaging system, and according to the output of the camera shake detection means. A method of driving the unit so as to correct image blur caused by camera shake. 3. In accordance with the output of the camera shake detection means, a part of the optical system is driven by the drive means to deflect the passing light flux,
A method for correcting image blur caused by camera shake (the driving method of an optical system includes a method of driving in a direction perpendicular to the optical axis, a method of rotating around an axis perpendicular to the optical axis, etc.). 4. According to the output of the camera shake detection means, the apex angle of the variable apex angle prism provided in the optical path is changed by the drive means,
A method of correcting image blur caused by camera shake by deflecting the passing light flux. 5. In an optical system having an image pickup device such as a CCD provided on the planned image forming plane of the optical system or a plane optically equivalent thereto, the image reading position on the image pickup device is changed according to the output of the camera shake detection means, and A method to correct the image blur that occurs. 6. In a device having an image pickup device such as a CCD provided on a planned image forming plane of an optical system or a plane optically equivalent thereto, the image output from the image pickup device is analyzed to detect image blur, and the detected output is detected. According to this method, the image blur is corrected by changing the image read position on the image sensor on the image sensor.

[0003]

However, the conventional optical system having the above-described image stabilization function (anti-vibration function) has the following drawbacks. 1) In the conventional methods 1 and 2, the entire optical system and the imaging system are supported by the gimbal mechanism, so that the entire apparatus is very large. 2) In the conventional method 3 as well, in order to move a part of the optical system in response to camera shake, there is also a support mechanism and drive means for the moving optical system, and the optical system is large, though not as much as the conventional methods 1 and 2, It's complicated. 3) The conventional method 4 can be made smaller than the conventional methods 1 and 2, but it requires a variable apex angle prism and its driving device, so that the optical system is large and the configuration is complicated. 4) The conventional method 5 is smaller than the conventional methods 1 to 4 because it does not have a movable portion for camera shake correction in the optical system unlike the conventional methods 1 to 4. However, similarly to the conventional methods 1 to 4, since the camera shake detecting means composed of an acceleration sensor or the like is required, a space for disposing the camera shake detecting means is required in the optical system. 5) The conventional method 6 does not have a movable portion for camera shake correction as compared with the other conventional methods, and since it does not require a camera shake detection dedicated means composed of an acceleration sensor or the like, the optical method has no camera shake correction function. It can be constructed in the same size as the system.

However, since the image output from the image sensor is analyzed to detect camera shake, when the angle of view of the optical system changes due to zooming or the like, the movement of the image due to zooming is also detected as image blur due to camera shake. As a result, the camera shake cannot be accurately detected, and the camera shake cannot be corrected.

Even so, when the object to be photographed has a relatively weak contrast and the image of the subject does not change so much even if the angle of view is changed by zooming, or in the direction from the center of the screen center. If the same state is also taken as a subject to be photographed, that is, if the image changes similarly in any direction when the angle of view is changed by zooming, etc., With respect to changes in the image due to zooming, the detection values from the plurality of detection areas are averaged, and the movement of the image due to zooming is not detected as image blur.

However, in other cases, for example, when the angle of view is changed from the wide side to the tele side, the object which is not displayed in the screen at the time of wide is changed to the tele side in the process of changing to the tele side. When coming in, the motion vector detected by the motion of the edge portion of the object is detected as a large value, and is detected as the motion of the image due to the camera shake.

[0007]

According to the present invention, an image blur is detected in accordance with an expected image forming surface of an optical system or an output of a photoelectric conversion means arranged at a position optically equivalent to the expected image forming surface. It is characterized in that it has variable means for changing the detection characteristic of the image blur detecting means according to the state of the optical system. With this configuration, the image blur can be accurately detected even when the image changes depending on the state of the optical system.

[0008]

EXAMPLE A first example of the present invention will be described below.

1 and 2 are sectional views of an image pickup apparatus according to a first embodiment of the present invention. In the figure, 1 is an image pickup optical system, 1a is a first group fixed lens, 1b is a zoom lens,
Reference numeral 1c is a third group fixed lens and 1d is a focus and zoom RR lens. Reference numeral 2 denotes a fixed portion, which holds a first group fixed lens 1a and a third group fixed lens 1c. Reference numeral 3 denotes a holding lens barrel for the V lens 1b, which has a sleeve portion 3a. Four
Is a holding barrel for the RR lens 1d, and the sleeve portion 4a
And has a screw portion 4b. 5 is a screw bar,
It has a groove having a certain lead, is engaged with the sleeve portion 3a, and is rotatably held by the holding barrel 2. 6 is an optical axis, 7 is a guide cover that restricts rotation of the holding barrel 3 in a plane perpendicular to the optical axis 6, 8 is a guide bar that engages with the sleeve 4a, and 9 is an optical axis 6 of the holding barrel 4. It is a guide bar that regulates rotation in a vertical plane. These three guide bars 7,
8 and 9 are held by the fixed portion 2. Reference numeral 10 denotes a ball, which is pressed by the spring 11 from the holding barrel 3 into the groove of the screw bar 5, thereby positioning the V lens 1b. Reference numeral 12 is a gear attached to the screw bar 5, 13 is a motor for moving the V lens 1b fixed to the fixed portion 2, 14 is a gear attached to the output shaft of the motor 13 and engaged with the gear 12, and 15 is fixed. It is a step motor for moving the RR lens 1d attached to the portion 2, and the screw portion 15a of the output shaft is screwed with the screw portion 4b. Reference numeral 16 is an aperture unit, 17 is a photoelectric conversion element (imaging element) such as CCD, 18 is an electronic viewfinder,
Reference numeral 19 is a finder lens, 20 is a camera power switch, 21 is a camera zoom operation switch, 22 is an encoder for detecting the position of the holding lens barrel 3 to detect the position of the V lens 1b, and 23 is an RR lens 1d. This is a switch for detecting the reference position of.

The camera has a camera control circuit, a recording section electrically connected to the camera control circuit, and a power source. Further, the motor 13, the step motor 15, the aperture unit 16, the photoelectric conversion element 17, the electronic viewfinder 18, the power switch 20, the zoom operation switch 2
1, the encoder 22, the switch 23, and the camera control circuit are electrically connected.

FIG. 2 is a block diagram showing a circuit configuration of the camera shown in FIG.

In FIG. 2, 31 is a camera control circuit for controlling the operation of the entire camera, 32 is an electronic viewfinder control circuit for controlling the operation of the electronic viewfinder 18, 33 is an exposure amount control circuit for controlling the aperture unit 16, Reference numeral 34 is a V lens position detection circuit for detecting the position of the V lens by the encoder 22, 35 is a V lens drive motor control circuit for controlling the drive of the motor 13, and 36 is an RR lens drive motor control circuit for controlling the drive of the step motor 15. Reference numeral 37 denotes an RR lens position detection circuit for detecting the position of the RR lens by the step motor 15 and the switch 23, and 38 denotes an angle-of-view change component and a magnification change for detecting an angle-of-view change component and a magnification-change component of a captured image, which will be described in detail later. A component detection circuit, 39 is an image sensor control circuit for controlling the photoelectric conversion element 17, 0 is a motion detection circuit that detects the motion of the subject in the captured image, 41 is a camera shake detection and correction circuit that detects and corrects camera shake, 42 is a recording unit control circuit that controls the recording unit, and 43 is A photographing switch not shown in FIG. 1 is a power switch 20 of the camera.
, 45 and 46 are zoom switches 1 and 2 and 47, which are the zoom operation switch 21 of the camera.
This is an anti-vibration switch (not shown in FIG. 1) for performing N and OFF.

Each of these circuits 32 to 42 is electrically connected directly or indirectly to the camera control circuit 31. Further, each of the circuits 32 to 42 is electrically connected directly or via the camera control circuit 31. The switches 43 to 47 are used for the camera control circuit 31.
Is electrically connected to.

FIG. 3 is a flow chart showing the operation of the camera shown in FIG. 1. The operation of the camera will be described below with reference to FIG.

When the power switch 20 of the camera is operated to turn on the power (S1), the step motor 15 is rotated, and the holding barrel 4 screwed with the output shaft 15a of the step motor 15, that is, the RR lens 1d. To the reference position. When the RR lens 1d reaches its reference position,
The switch 23 is turned on, and there the step motor 1
Stop energizing 5 (S2). Further, the driving of the photoelectric conversion element (imaging element) 17 is started. The absolute position of the RR lens 1d can be detected by counting the pulse current applied to the step motor from this reference position. Further, the RR lens 1d is slightly vibrated in the optical axis direction, and the RR lens 1d is moved to a position where the high frequency component of the video signal of the photoelectric conversion element 17 is maximized, whereby the focusing operation is performed (S3). The exposure amount is controlled by controlling the aperture diameter of the aperture unit 16 by the aperture control circuit so that the amount of light incident on the photoelectric conversion element 17 is constant (S).
3). The image obtained by the photoelectric conversion element 17 is displayed on the electronic viewfinder 18 and can be viewed by the photographer (S4).
Then, this state is set as a standby state.

When the zoom operation switch 21 is operated,
By rotating the motor 13 and the step motor 15, the V lens 1b and the RR lens 1d are moved in the optical axis direction. When the motor 13 is rotated here, the rotation of the motor 13 is transmitted through the gear 14 and the gear 12 to the screw bar 5
And the ball 10 is pressed by the holding barrel 3 into the groove portion having the lead of the screw bar 5,
The rotation of the screw bar 5 causes the V lens 1b to move in the optical axis direction. The position of the V lens 1b is detected by the encoder 22 (S5). Here, the principle of the zoom operation performed by moving the V lens 1b and the RR lens 1d in the optical axis direction will be described with reference to FIGS. FIG. 4 is a map for displaying the relative positional relationship between the V lens 1b and the RR lens 1d for each subject, and FIG. 5 is a division of FIG. The length shown in FIG. 4 (0.002 m, 0.4
m, 2m, ∞) is the distance from the camera to the subject.
When the V lens 1b is changed from wide angle (W) to telephoto (T), the RR lens 1d will be out of focus unless moved to the position shown in FIG. 4 depending on each subject distance.
Therefore, when the V lens 1b is moved, it is necessary to move the RR lens 1d according to the map shown in FIG. However, the map shown in FIG. 4 shows the positional relationship between the V lens 1b and the RR lens 1d having a typical subject distance, and the map of all subject distances is stored and the RR is calculated according to the position of the V lens 1b. When the lens 1d is moved, an enormous storage capacity is needed to store the map. By the way, change V lens 1b to T → W or W
→ Move in the T direction at a constant speed, and as shown in FIG. 5, the map of FIG. 4 is divided into areas I, II ... And each area is divided into areas corresponding to the moving direction and the moving speed of the V lens 1b.
If the moving direction and moving speed of the R lens 1d are stored and the RR lens 1d is moved by the movement of the V lens 1b based on this information, the map shown in FIG. 4 can be traced. Note that this method is known from, for example, Japanese Patent Application Laid-Open No. 1-280709.

The zoom operation switch 21 is provided with a zoom switch 1 and a zoom switch 2. When the zoom switch 1 is turned on (S10, S18), the motor 1
3 rotates normally, and the V lens 1b moves to the wide-angle side (S11, S1
9), the area is determined (S6), and the selected map (S
The RR lens 1d moves according to 7) (S11, S1).
9). When the zoom switch 2 is turned on (S12, S2
0) The motor 13 reversely rotates, the V lens 1b moves to the telephoto side (S13, S21), the area is determined (S6), and the RR lens 1d moves according to the selected map (S7) (S).
13, S21). Further, the zoom switch 1 and the zoom switch 2 cannot be turned on at the same time. If the zoom switches 1 and 2 are not ON, the zoom operation is stopped (S15, S17). When the photographer presses a photographing button (not shown), the photographing switch is turned on (S8,
S14), when the camera control circuit confirms that the shooting switch is turned on, shooting is started, and the video signal from the photoelectric conversion element 17 is transferred to the recording unit by the camera control circuit,
Recording is performed on the recording medium by the recording control circuit (S9).

At this time, the focusing operation and the exposure amount adjustment described above are performed, and the image is displayed on the electronic viewfinder 18
Is displayed in. When the photographer releases the photographing button (not shown), the photographing switch is turned off, and when the camera control circuit confirms that the photographing switch is turned off, the photographing operation is stopped (S16) and the camera returns to the standby state.

FIG. 6 is a flow chart showing the image stabilizing operation of the video camera of this embodiment. The operation will be described below with reference to FIG.

When a vibration isolation operation (not shown) is turned on (S3
0), the counter is set to 0 (S31). Then, 1 is added to the counter (S32) <If the counter is larger than 1 (S33), the V lens movement vector and the RR lens movement vector are detected (S34). Then, the angle-of-view change vector is detected (S35). The position and size of the motion vector detection range and the representative point are adjusted by the angle-of-view change vector (S36), and the motion vector is detected (S37). Here, with reference to FIGS.
The operation of S37 will be specifically described.

First, when an anti-vibration switch (not shown) is turned on, the range of the chain line in the image on the image pickup surface shown in FIG. 7A is output as shown in FIG. 7B.

When camera shake occurs in this state, the subject image moves on the image pickup surface as shown in FIGS. 8 (a) to 8 (c). This blurring of the subject image is shown in FIG.
In the frame (5 places) indicated by the alternate long and short dash line shown in (c).
The detection is performed by comparing the image signal of one field before and the image signal of the current field to obtain the direction and amount (motion vector) of the motion of the image. Then, in accordance with this motion vector, the range of the output screen shown by the chain line in FIG. 8 is translated and the camera shake is corrected. This is a camera control circuit,
This is performed by a camera shake detection circuit, a motion detection circuit, and an image sensor control circuit. Further, there are a plurality of representative points in the frame of the one-dot chain line in FIG. 8, and the correlation calculation between the data of the representative point one field before and each pixel around the representative point of the current field is performed for all the representative points, Find the vector. Also,
Whether the motion vector obtained here is due to camera shake,
The following method is used to determine whether it is due to the movement of the subject. 1) When different motion vectors are detected and the difference becomes larger and larger, a moving subject exists in the screen. 2) When all the motion vectors are in the same direction and their differences are small, the camera is in a camera shake state.

That is, in the case of 1 above, the range of the output screen (the range of the chain line in FIG. 8) is not changed, and in the case of 2 above, the range of the output screen is changed and the camera shake is corrected assuming that camera shake has occurred. Of.

When a zoom operation or a focus operation is performed in such a vibration-proof operation state, as shown in FIG.
The angle of view changes as shown in (c), FIG. 10 (a), and (b). It should be noted that FIG. 9A shows a state in which the angle of view is minimum, and the angle of view becomes larger as in FIGS. 10B and 10C, and in FIG. 10B, the angle of view is maximum. In such a case, the output range of the image on the imaging surface does not change, but as shown in FIGS. 9 and 10, the motion vector detection range (indicated by the dashed line in FIGS. 9 and 10) is changed according to the change in the angle of view. ) Changes its size and position.

Further, as shown in FIG. 9C, a new motion vector detection range is provided at a certain angle of view when the angle of view becomes small → large or when the angle of view becomes large → small.
Motion vector detection is performed, and motion vector detection in the motion vector detection range up to that point is stopped. The positions of the plurality of representative points described above also change depending on the size and position of the motion vector detection range. In this way, by obtaining the motion vector, the effect of changing the angle of view can be removed,
Only the camera shake component is detected. Here, the size and position of the motion vector detection range and the representative point included therein on the imaging surface are determined by the angle of view or the speed of change of the angle of view. To detect the angle of view, the position of the V lens 1b and the position of the RR lens 1d are determined by the encoder 22, the step motor 15, and the switch 2.
It is performed by 3. Further, when detecting the changing speed of the angle of view, the encoder 22, the step motor 15 and the switch 23 similarly detect the changing speed. Further, when the electronic zoom function is provided, the size of the range of the chain line (image output range) shown in FIGS. 7 to 10 is changed. In such a case, the movement is performed according to the change of the size of the image output range. By changing the size of the vector detection range, only the camera shake component is detected.

The continuation of the flowchart of FIG. 6 will be described.
When the motion vector is detected in S37, next, when there is a difference of a certain value or more between the motion vector of each representative point and the average value of the motion vectors (S38), this motion vector is excluded (S39). When there are three or more vectors (S
40), and when each motion vector is not a certain value or more (S41), and when the counter is 10 or more (S4).
2) and when the direction of each motion vector is the same from 10 fields before (S43), camera shake correction is not performed (S44). When the remaining motion vectors are not three or more (S40), or when each motion vector is a certain value or more (S41), the camera shake correction is not performed (S4).
4). When the directions of the respective motion vectors are not the same from 10 fields before (S43), the camera shake correction amount of the field image at this time is calculated (S45). When the camera shake correction screen deviates from the input screen (S46), the camera shake correction is not performed (S44). When the image stabilization screen does not deviate from the input screen (S46), image stabilization is performed on this field image (S47), and this field image is output (S48).

If the counter is not 1 or more (S3
3) and when the image stabilization is not performed (S44), the feel image is output as it is (S48). If the image stabilization switch is ON (S49), the field image is stored in the memory (S50) and the process returns to S32. If the image stabilization switch is not ON (S49), the image stabilization operation is stopped (S51).

Further, in the above embodiment, the motion vector detection range is five, but it may be any number.

Further, in S34 to S37 of FIG. 6, V
From the movement direction and movement speed of the lens 1b and the RR lens 1d, the motion vector detection range, and the position of the representative point, a subject image movement vector (angle-of-view change vector) on the imaging surface due to a change in the angle of view is obtained. A motion vector due to camera shake may be detected from the detected motion vector of the subject image.

[0030]

As described above, according to the present invention,
Even when the image changes according to the state of the optical system, for example, when the angle of view changes due to zooming and the image moves, the image blur can be accurately detected.

Further, instead of the angle of view, the motion vector due to the camera shake may be detected based on the photographing magnification or the changing speed thereof, or the motion vector due to the camera shake may be detected based on both the angle of view and the photographing magnification and their changing speeds. Good.

Further, the photographing optical system 1 is not limited to the form of the above-mentioned embodiment, and may be any optical system as long as it has a photographing angle of view detecting device such as a zoom position detecting device and a focus position detecting device. .

In addition, a photoelectric conversion element such as an image pickup element is provided on a surface optically equivalent to the image pickup surface such as a secondary image formation surface, and a silver halide camera or other optical equipment for performing autofocusing by this element. You may use.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a camera that is an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a camera that is an embodiment of the present invention.

FIG. 3 is a flow chart for controlling the operation of the camera of the embodiment of the present invention.

FIG. 4 is a map showing a relative positional relationship between two movable lenses for each subject.

FIG. 5 is a diagram obtained by dividing FIG. 4;

FIG. 6 is a flowchart for controlling the image stabilization operation of the camera of the embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a relationship between a subject image on an imaging surface and an output image.

FIG. 8 is an explanatory diagram showing a relationship between a subject image in which a camera shake occurs on an imaging surface and an output image range.

FIG. 9 is an explanatory diagram showing a camera shake detection area on the imaging surface during a change in the angle of view.

FIG. 10 is an explanatory diagram showing a camera shake detection area on the imaging surface during a change in the angle of view.

[Explanation of symbols]

 1 Photographic optical system 17 Photoelectric conversion element 22 Encoder for detecting the position of the lens 23 Switch for detecting the reference position of the lens

Claims (3)

[Claims] 1. Detection of an image blur according to an output of a planned image forming surface of an optical system or a photoelectric conversion means arranged at a position optically equivalent to the planned image forming surface. A control device for detecting an image blur, comprising variable means for changing a characteristic according to a state of the optical system. 2. The image blur detection according to claim 1, wherein the variable unit changes a detection range on the image plane of the photoelectric conversion unit when the image blur detection unit detects the image blur. Control device for. 3. The control device for image blur detection according to claim 1, wherein the optical system is for changing a focal length.