JP2007189384A - Imaging apparatus, control method, and control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely conduct a photographing when a photographing condition is satisfied in the case of an actual photographing. <P>SOLUTION: A digital steel camera 1 has a hand shaking-quantity detector 30 detecting the quantity of a hand shaken. A CPU 11 decides whether or not the specified photographing condition containing the quantity of the hand shaken is satisfied. The CPU 11 conducts a photographing processing in an auto-shutter mode automatically releasing a shutter when the photographing condition is satisfied. The CPU 11 releases the auto-shutter mode when the photographing condition is not satisfied during the auto-shutter mode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, a control method, and a control program, and more particularly to a technique for reducing image blurring in an auto shutter mode in an imaging apparatus having an auto shutter mode (automatic shooting mode).

2. Description of the Related Art Conventionally, in an imaging apparatus such as a digital still camera that captures a still image, various methods have been proposed to avoid the influence of camera shake that occurs during shooting.
In such an imaging apparatus, an apparatus having an auto shutter mode in which the imaging apparatus automatically performs shooting has been proposed in order to suppress camera shake during a shutter operation.
For example, in the technique described in Patent Document 1, a subsequent blur is predicted based on the amount of blur acquired from the blur detection unit, and shooting is performed by performing autofocus control when the blur reaches a predetermined value.
In the technique described in Patent Document 2, when the angular velocity of the camera reaches a predetermined condition, the imaging device performs autofocus control and automatically performs imaging.
Japanese Patent Laid-Open No. 10-48681 JP 2001-235882 A

However, in any of the above-described techniques, there has been a problem that a captured image is blurred due to camera shake or the like that occurs after the end of autofocus control.
SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging apparatus, a control method, and a control program that can reliably perform imaging when imaging conditions are satisfied during actual imaging.

In order to solve the above problems, an imaging apparatus includes a camera shake amount detection unit that detects the amount of camera shake, a shooting condition determination unit that determines whether a predetermined shooting condition including the amount of camera shake is satisfied, and the shooting condition. An auto-shutter operation unit that performs shooting processing in an auto-shutter mode that automatically releases the shutter when the shutter is satisfied, and cancels the auto-shutter mode when the shooting condition is not satisfied during the auto-shutter mode. And an automatic shutter release unit.
According to the above configuration, the camera shake amount detection unit detects the amount of camera shake, and the imaging condition determination unit determines whether or not a predetermined imaging condition including the amount of camera shake is satisfied.
As a result, when the shooting condition is satisfied, the auto shutter operation unit performs shooting processing in the auto shutter mode in which the shutter is automatically released, and the auto shutter release unit performs the shooting condition during the auto shutter mode. When it is no longer possible, the auto shutter mode is canceled.
In this case, it is determined whether or not the camera shake amount is larger than a predetermined data reacquisition shake amount, and when the camera shake amount is larger than a predetermined data reacquisition shake amount, the camera shake amount detection unit again receives the camera shake amount detection unit. The amount of camera shake may be acquired again.
Also, based on the autofocus mechanism that automatically focuses on the subject and drives the lens to the in-focus position, and the amount of camera shake in the optical axis direction of the lens prior to performing the shooting process in the auto shutter mode. An autofocus correction unit that corrects the in-focus position and performs correction control to drive the lens to the corrected in-focus position may be provided.
Further, it is determined whether or not the camera shake amount is larger than a predetermined autofocus redetermination blur amount, and when the camera shake amount is larger than a predetermined autofocus redetermination blur amount, the autofocus mechanism unit again receives the camera shake amount. An autofocus reset control unit that drives the lens to a new in-focus position may be provided.
Furthermore, the camera shake amount detection unit may include a gyro sensor and detect the camera shake amount based on an angular velocity detection signal output from the gyro sensor.
Further, in a control method of an imaging apparatus including a camera shake correction mechanism that performs camera shake correction on an image captured based on a camera shake amount, a camera shake amount detection process for detecting the camera shake amount and a predetermined photographing condition including the camera shake amount are satisfied. A shooting condition determination process for determining whether or not the shooting has been performed, an auto shutter operation process for performing shooting processing in an auto shutter mode in which a shutter is automatically released when the shooting condition is satisfied, and the auto shutter mode during the auto shutter mode. An auto-shutter release process for releasing the auto-shutter mode when shooting conditions are no longer satisfied.
Further, in a control program for controlling, by a computer, a camera shake amount detection device that detects a camera shake amount, and an image pickup device that includes a camera shake correction mechanism that performs camera shake correction on an image captured based on the detected camera shake amount, the amount of camera shake is determined. And detecting whether or not a predetermined shooting condition including the amount of camera shake is satisfied. When the shooting condition is satisfied, shooting is performed in an auto shutter mode in which the shutter is automatically released, and the auto The auto shutter mode is canceled when the photographing condition is not satisfied during the shutter mode.

Next, an optimum embodiment of the present invention will be described with reference to the drawings.
In this embodiment, a case where the present invention is applied to a portable digital still camera (hereinafter simply referred to as “digital still camera”) as one embodiment of an electronic device will be described.
FIG. 1 is a schematic block diagram of a digital still camera according to an embodiment.
As shown in FIG. 1, the digital still camera 1 includes a control unit 10, a photographing unit 20, a camera shake amount detection unit (angular velocity detection unit) 30, an operation unit 40, a removable medium 50, an I / F unit 51, and a video output terminal 52. It has.

  The control unit 10 functions as a control unit that controls each unit of the digital still camera 1, and includes a CPU 11 that executes various programs and performs arithmetic processing, and a rewrite that stores a control program 100 executed by the CPU 11 and various data. A possible flash ROM (hereinafter simply referred to as “ROM”) 12, a RAM 13 functioning as a work area for temporarily storing the calculation results and various data of the CPU 11, and a timer circuit for measuring time in self-timer shooting or the like 14. The control program 100 stored in the ROM 12 includes a moving image display processing program for realizing autofocus correction.

  The control program 100 can be recorded and distributed on a computer-readable recording medium 60 such as a CD-ROM, DVD-ROM, or flexible disk. Further, the personal computer and the digital still camera 1 are communicably connected by a cable or the like, and the control program 100 of the recording medium 60 read by the personal computer is output to the still camera 1, whereby the control program 100 is stored in the flash ROM 12. Can also be stored.

Next, the imaging unit 20 captures a subject as a still image, and includes a camera control circuit 21, a photographing camera 22, a photographing unit RAM 23, and a display panel 24. The camera control circuit 21 controls each unit of the photographing unit 20 under the control of the control unit 10. The photographing camera 22 takes an image with a CCD sensor or a CMOS image sensor and outputs corresponding image data to the camera control circuit 21. In this case, in a CCD or CMOS image sensor, photoelectric conversion elements are two-dimensionally arranged in a matrix or honeycomb. The imaging camera 22 includes an optical lens system having a plurality of optical lenses, a lens driving device for driving the optical lens system to realize zoom, focus, and the like, and an aperture for performing automatic exposure. An aperture driving device for realizing the configuration, an A / D conversion circuit for converting an analog signal acquired by a CCD or a CMOS image sensor into a digital signal and outputting it as image data are configured.
The photographing unit RAM 23 temporarily stores image data.

The display panel 24 displays various information such as a photographed still image and a setting screen, and is configured by a flat display panel such as a liquid crystal display panel or an organic EL panel.
The removable medium 50 stores moving image data at the time of shooting, and includes, for example, a video tape, a recordable optical disk, and a removable hard disk.
Under such a configuration, the image data of the frame output from the photographing camera 22 is subjected to predetermined image processing by the camera control circuit 21, and then temporarily stored in the photographing unit RAM 23. Then, it is sequentially possible as moving image data on the removable medium 50. The image data stored in the imaging unit RAM 23 is used when a still image shot on the display panel 24 is displayed in live view, and the image data of the still image stored in the removable medium 50 is a still image after shooting. Used when displaying.

FIG. 2 is an explanatory diagram of an axis of angular velocity detected by the camera shake amount detection unit.
The camera shake amount detection unit (angular velocity detection unit) 30 functions as a camera shake amount detection unit that detects the camera shake amount. Specifically, as shown in FIG. 2, the camera shake amount detection unit 30 moves the frame 70 in the height direction (hereinafter referred to as the X axis) and in the horizontal direction (hereinafter referred to as the Y axis). 1 has two gyro sensors 31, 32, an X-axis gyro sensor 31 and a Y-axis gyro sensor 32, as shown in FIG. Outputs an angular velocity detection signal having a voltage value corresponding to the angular velocity to the control unit 10.
The control unit 10 takes in the angular velocity detection signals of the gyro sensors 31 and 32 in synchronization with the sampling period of the frame 70, calculates the camera shake amount for each of the X axis and the Y axis, and associates it with the image data of the frame 70. Alternatively, it is added to the image data and stored in the removable medium 50.

  In this embodiment, the gyro sensors 31 and 32 are used to calculate the integral angular velocity during a predetermined sampling period, and thus the camera shake amount θ (X-axis direction camera shake amount θx and Y-axis direction camera shake amount θy) during the predetermined sampling period. However, since the voltage value of the angular velocity detection signal when the angular velocity (rad / sec) is zero varies depending on individual differences of the gyro sensors 31, 32, etc., in this embodiment, imaging is performed after the power of the main body is turned on. Before starting the operation, the angular velocity detection signals of the respective gyro sensors 31 and 32 are sampled, and the average value is set as the zero point voltage value. At this time, when a plurality of zero point voltage values are obtained over a certain period of time, and the difference between the zero point voltage values and the average value of these zero point voltage values is equal to or less than a predetermined value, a certain percentage (eg, 99%) or more In addition, the average value of the zero point voltage values is set as the actual zero point voltage value, which makes it possible to set the zero point voltage value when the main body is in a stopped state.

  The operation unit 40 includes a plurality of operation elements operated by a user, and includes, for example, a power button and operation keys for inputting various instructions such as shooting start / end. The I / F unit 51 is an interface for connecting the still camera 1 to a personal computer via a cable or the like so that the image data stored in the removable medium 50 is output to the personal computer. The data is output to the personal computer via the I / F unit 51. The video output terminal 52 is a terminal for outputting a video signal corresponding to image data to an external display device such as a television or a projector. In addition to the above-described components, the still camera 1 includes an audio circuit for capturing and recording / reproducing audio signals, an audio output terminal for outputting audio signals to an external speaker, an external amplifier, and the like. I have.

Next, the operation will be described.
FIG. 3 is a processing flowchart of the embodiment.
First, the CPU 11 turns on the auto shutter function for automatically releasing the shutter when a predetermined photographing condition is satisfied (step S11).
Next, when the shutter switch is half-pressed, the CPU 11 controls the camera control circuit 21 to perform automatic focus (autofocus) control (step S12).
FIG. 4 is an explanatory diagram when autofocus control is performed by the contrast detection method.
According to the contrast detection method, the lens is actually driven and the position with the highest contrast is set as the focal point. That is, since the lens position P in FIG. 4 is the in-focus position, the lens is fixed at this position P and the autofocus lock state is set.

Subsequently, the CPU 11 controls the camera control circuit 21 to perform automatic exposure control and sensitivity (ISO sensitivity) setting (step S13).
When the shutter switch is fully pressed, the CPU 11 is based on the angular velocity detection signals that are output signals of the X-axis gyro sensor 31 and the Y-axis gyro sensor 32 that are motion sensor data via the camera shake amount detection unit 30. The movement amount is acquired, and the average value X of the movement amounts of the most recent samples is calculated (step S14).
Here, the calculation of the motion amount will be briefly described. The CPU 11 calculates an angular velocity (rad / second) based on the angular velocity detection signal, and integrates the angular velocity (rad / second) at a predetermined sampling interval (second). To calculate the integral angular velocity Σ (rad / sec). Actually, the control unit 10 calculates the X-axis direction integral angular velocity Σx and the Y-axis direction integral angular velocity Σy as the integral angular velocity, that is, the amount of motion.

Subsequently, the CPU 11 determines whether or not the average value X of the motion amount is smaller than the reference blur amount P, that is,
X <P
It is discriminate | determined whether it is (step S15).
In the determination of step S15, the average value X of the motion amount is smaller than the reference blur amount P, that is,
X <P
If it is, it is assumed that shooting conditions including autofocus, exposure, and camera shake are satisfied, and shooting processing is performed (step S21).
Here, the photographing process will be described.
In the photographing process, the CPU 11 determines whether the panning operation of the digital still camera has been performed based on the X-axis direction integral angular velocity Σx and the Y-axis direction integral angular velocity Σy. Here, the panning operation means, for example, that the person is placed at the center of the screen and the shutter switch is half-pressed to set the autofocus lock state for the person, and then the direction of the digital still camera is changed, and the side of the screen is changed. This is an operation to correct the composition so that a person is placed on the screen.

In the panning operation determination, when the panning operation is performed in the digital still camera, it is necessary to maintain the autofocus lock state without considering camera shake, so the process immediately proceeds to the image data capturing process, and in step S12 The lens is fixed at the in-focus position where the autofocus lock is set by the autofocus control, the image is taken by the photographing camera 22, and the obtained image data is temporarily taken into the photographing unit RAM 23, and the control of the control unit 10 is performed. Below, the image data capturing process to be recorded on the removable medium 50 is performed. The captured image is displayed on the display panel 24 in parallel with the recording operation of the image data on the removable medium 50.
In the determination in step S15, when the average value X of the motion amount is equal to or larger than the reference blur amount P, that is,
X ≧ P
In this case, assuming that the photographing condition is not yet satisfied, the CPU 11 determines whether or not the motion amount average value X reconfirms the camera shake amount, and determines whether or not the data reacquisition shake amount Q (> P ) Or less, that is,
X <Q
It is determined whether or not (step S16).

In the determination in step S16, the average value X of the motion amount is smaller than the data reacquisition blur amount Q, that is,
X <Q
If YES in step S14, the process returns to step S14, and the CPU 11 detects the angular velocity that is output signals of the X-axis gyro sensor 31 and the Y-axis gyro sensor 32 that are motion sensor data via the camera shake amount detection unit 30. The amount of motion is acquired based on the signal, the average value X of the amount of motion of the most recent samples is calculated, and the process proceeds to step S15.
In the determination of step S16, when the average value X of the motion amount is equal to or greater than the data reacquisition blur amount Q, that is,
X ≧ Q
If it is, the CPU 11 determines whether or not the average value X of the motion amount is smaller than the AF correction blur amount R1 (>Q> P) in order to determine whether the influence of the autofocus shift can be avoided by the correction. That is,
X <R1
It is discriminate | determined whether it is (step S17).
In the determination in step S17, the average value X of the motion amount is smaller than the AF correction blur amount R1, that is,
X <R1
If YES, the process shifts to an autofocus correction process (step S20).

Here, the autofocus correction process will be described.
FIG. 5 is a diagram for explaining the principle of autofocus correction processing.
As shown in FIG. 5, the difference DF between the in-focus position P when there is no camera shake and the in-focus position P1 when camera shake occurs, and the movement amount DX caused by the camera shake of the CCD of the digital still camera 11 There is a correlation between them. Therefore, if the movement amount DX caused by camera shake of the digital still camera 11 can be detected, the in-focus position should be able to be corrected from the position P to the position P1.

FIG. 6 is an explanatory diagram of the autofocus correction process in the X-axis direction.
FIG. 7 is an explanatory diagram of autofocus correction processing in the Y-axis direction.
In the autofocus correction process, the CPU 11 calculates an autofocus correction amount ΔL based on the calculated X-axis direction camera shake amount θx and the Y-axis direction camera shake amount θy.
Specifically, first, as shown in FIG. 6, the autofocus correction amount ΔLy in the Y-axis direction is calculated by the following equation based on the Y-axis direction camera shake amount θy.
ΔLy = L−L / cos θy
As a result, the apparent distance L1 to the subject OB1 in which the camera shake amount is corrected only in the Y-axis direction is expressed by the following equation.
L1 = L + ΔLy

Subsequently, as shown in FIG. 7, the CPU 11 calculates an autofocus correction amount ΔLx in the X-axis direction by the following equation based on the X-axis direction camera shake amount θx and the apparent distance L1 to the subject OB1.
ΔLx = L1-L1 / cos θx
Based on these results, the CPU 11 calculates an autofocus correction amount ΔL.
ΔL = ΔLx + ΔLy
Then, the CPU 11 controls the camera control circuit 21 to perform autofocus correction processing based on the autofocus correction amount ΔL, and newly sets a position shifted by the autofocus correction amount ΔL from the in-focus position obtained in step S13. The focus position is set to the correct focus position, and the process proceeds to the photographing process (step S21).

Then, the lens is fixed at a new in-focus position that has been brought into the autofocus locked state by the autofocus correction process in step S20, and the image is captured by the photographing camera 22, and the obtained image data is temporarily stored in the photographing unit RAM23. At the same time, the image data capturing process of recording on the removable medium 50 under the control of the control unit 10 is performed. The captured image is displayed on the display panel 24 in parallel with the recording operation of the image data on the removable medium 50.
In the determination in step S17, the average value X of the motion amount is not less than the AF correction blur amount R1, that is,
X ≧ R1
If it is, in order to determine whether or not the autofocus control should be redone, the CPU 11 determines whether or not the average value X of the motion amount is smaller than the AF redetermination blur amount R2 (>R1>Q> P). ,
X <R2
It is discriminate | determined whether it is (step S18).

In the determination in step S17, the average value X of the motion amount is smaller than the AF redetermination blur amount R2, that is,
X <R2
If so, the process again proceeds to step S12, and the same process is performed thereafter.
In the determination in step S17, the average value X of the motion amount is not less than the AF redetermination blur amount R2, that is,
X ≧ R2
In this case, since shooting using the auto shutter function is difficult, the CPU 11 turns off the auto shutter function and ends the process (step S19).
As described above, according to the present embodiment, it is automatically determined by determining whether or not shooting conditions that enable shooting based on autofocus (automatic focus position), exposure, and camera shake are satisfied during actual shooting. The shutter can be released automatically. Furthermore, when the auto shutter function is used, camera shake after autofocus can be automatically corrected, and a more focused image can be obtained.

In the above description, the case where the contrast detection method is used to detect the in-focus position has been described, but various methods can be used as the autofocus position detection method. In other words, an active detection method that detects the distance based on the time until the reflected wave returns and the irradiation angle based on the same principle as a radar, and a phase difference detection method. This passive detection method can also be applied.
In the above description, the gyro sensor, which is a motion sensor, has been described on the assumption that it is always driven, but whether or not the composition at the time of shooting is determined, for example, the degree of cross-correlation between multiple frames When the composition is determined based on the above, it is possible to supply power to the gyro sensor which is a motion sensor or to increase the operating frequency. By adopting such a configuration, power consumption can be reduced.
In the above description, the case where the operation is always started in the auto shutter mode has been described. However, when the structure at the time of shooting is determined by the above-described method or the like, the auto shutter mode can be configured. is there.
In the above description, the digital still camera has been described. However, the present invention can be applied to other optical images such as a camera provided in a mobile phone, a PDA integrated camera, and a single-lens reflex camera.
In the above description, the configuration in which the shake amount is detected based on the angular velocity is illustrated, but the configuration is not limited thereto, and a configuration in which the shake amount (motion amount) is detected using an acceleration sensor may be employed.

1 is a schematic configuration block diagram of a digital still camera of an embodiment. It is explanatory drawing of the axis | shaft of angular velocity. It is a processing flowchart of an embodiment. It is explanatory drawing in the case of performing autofocus control by a contrast detection method. It is a principle explanatory view of autofocus correction processing. It is explanatory drawing of the autofocus correction | amendment process in a Y-axis direction. It is explanatory drawing of the autofocus correction | amendment process in a X-axis direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Digital still camera, 10 ... Control part (shake amount detection part, auto shutter operation part, auto shutter release part), 11 ... CPU (hand shake amount detection part, auto shutter action part, auto shutter release part), 20 ... Shooting , 21... Camera control circuit (autofocus correction unit), 22 .. photographic camera (autofocus mechanism unit), 24... Display panel, 30. Hand shake amount detection unit (angular velocity detection unit), 50. Medium, 70 ... frame.

Claims (7)

A camera shake amount detection unit for detecting a camera shake amount;
A shooting condition determining unit that determines whether or not a predetermined shooting condition including the amount of camera shake is satisfied;
An auto-shutter operation unit that performs shooting processing in an auto-shutter mode that automatically releases the shutter when the shooting condition is satisfied;
An auto shutter release unit for releasing the auto shutter mode when the shooting condition is not satisfied during the auto shutter mode;
An imaging apparatus comprising: The imaging device according to claim 1,
It is determined whether or not the camera shake amount is larger than a predetermined data re-acquisition shake amount, and when the camera shake amount is larger than a predetermined data re-acquisition shake amount, the camera shake amount detection unit again re-establishes the camera shake amount. An imaging apparatus characterized by being acquired. The imaging apparatus according to claim 1 or 2,
An auto-focus mechanism that automatically focuses on the subject and drives the lens to the in-focus position;
Prior to performing the photographing process in the auto shutter mode, correction control is performed to correct the focal position based on the amount of camera shake in the optical axis direction of the lens and drive the lens to the corrected focal position. An autofocus correction unit to perform,
An imaging apparatus comprising: The imaging device according to claim 3.
It is determined whether or not the camera shake amount is larger than a predetermined autofocus redetermination blur amount.If the camera shake amount is larger than a predetermined autofocus redetermination blur amount, the lens is again attached to the autofocus mechanism. An image pickup apparatus comprising an autofocus reset control unit for driving to a new in-focus position. The imaging apparatus according to any one of claims 1 to 4,
The imaging apparatus according to claim 1, wherein the camera shake amount detection unit includes a gyro sensor and detects the camera shake amount based on an angular velocity detection signal output from the gyro sensor. In a control method of an imaging apparatus including a camera shake correction mechanism that performs camera shake correction on an image captured based on the amount of camera shake,
Camera shake amount detection process for detecting the amount of camera shake,
A shooting condition determination process for determining whether or not a predetermined shooting condition including the amount of camera shake is satisfied;
An auto-shutter operation process of performing shooting processing in an auto-shutter mode that automatically releases the shutter when the shooting conditions are satisfied;
An auto shutter release process for releasing the auto shutter mode when the shooting condition is not satisfied during the auto shutter mode;
An image pickup apparatus control method comprising: In a control program for controlling, by a computer, a camera shake amount detection device that detects the amount of camera shake, and an imaging device that includes a camera shake correction mechanism that performs camera shake correction on an image captured based on the detected camera shake amount.
Detect the amount of camera shake,
Determining whether a predetermined shooting condition including the amount of camera shake is satisfied;
When the shooting conditions are satisfied, the shooting process is performed in an auto shutter mode in which the shutter is automatically released,
Canceling the auto shutter mode when the shooting condition is not satisfied during the auto shutter mode;
A control program characterized by that.

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