JPH07218956A - Camera-shake correction camera - Google Patents

Abstract

PURPOSE:To perform very accurate camera-shake correction by starting the camera-shake correction when a specified time elapses after starting detecting camera shake. CONSTITUTION:This invention is applied to a camera-shake correction camera provided with a CPU 2, motor driving circuits 8 and 9, a shake display unit 13, angular velocity detection circuits 21 and 22, and a correction lens 102. By half-depressing a release button, the CPU 2 starts the detection circuits 21 and 22 after performing battery check. Thereafter, when the specified time elapses after fully depressing the release button, a signal is transmitted to the driving circuits 8 and 9 so as to move the lens 102, and shutter opening/closing processing is performed when the specified time elapses after the movement of the lens 102. Thus, the accuracy in the camera-shake correction is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera shake correction camera which detects a camera shake generated in a camera and corrects the camera shake based on the detection result to perform photographing.

[0002]

2. Description of the Related Art A camera shake correction camera is known which is capable of detecting a camera shake generated in a camera and correcting the camera shake. In this type of camera, a sensor that measures an angular velocity, an acceleration, and the like caused by camera shake, and a sensor circuit that drives the sensor and detects a sensor output are provided in the camera. Although the sensor outputs a signal according to the amount of camera shake, since the signal amplitude is generally small, an amplifier for amplifying the sensor output is provided in the sensor circuit. In order to improve the hand-shake detection sensitivity of the sensor circuit, the power supply voltage supplied to the amplifier may be increased, but this also has a certain limitation. Therefore, generally, the DC component of the sensor output is cut and input to the amplifier, and the amount of camera shake is detected by the magnitude of the amplitude of the AC component of the sensor output.

[0003]

However, if the DC component is cut and amplified, the reference level of the amplified signal, that is, the signal level when there is no camera shake cannot be easily detected. In order to obtain this reference level, for example, the amplifier output may be averaged based on the result of time-differentiating the amplifier output. However, in order to perform time differentiation and averaging of the amplifier output, the amplifier output must be continuously measured for a predetermined time. Further, since the sensor output contains noise, noise reduction processing and the like must be performed, and the higher the accuracy of the reference level, the longer it takes for the reference level to be obtained. is there. On the other hand, if the camera shake correction is performed without detecting the reference level, there is a possibility that a correction different from the actual camera shake may be performed, such as moving the correction lens even though the camera shake does not actually occur.

An object of the present invention is to start camera shake correction after a predetermined time has elapsed after starting camera shake detection,
An object of the present invention is to provide a camera shake correction camera that is capable of highly accurate camera shake correction.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIG. 1 showing an embodiment. According to the present invention, camera shake detecting means 21 and 22 for detecting camera shake generated in a camera, and at least during exposure, It is applied to a camera shake correction camera equipped with a camera shake correction means 102 for correcting the detected camera shake, and after the predetermined time has elapsed since the detection by the camera shake detection means 21, 22 was started, the correction by the camera shake correction means 102 is started. The above-mentioned object is achieved by providing the control means 2 for controlling. According to a second aspect of the present invention, in the camera shake correction camera according to the first aspect, a reference level calculating unit 2 for calculating a reference level for detecting a camera shake is provided based on the outputs of the camera shake detecting units 21 and 22. After the reference level is calculated, the camera shake correction means 10 is provided.
The control means 2 is configured to start the correction by 2. According to a third aspect of the present invention, in the camera shake correction camera according to the second aspect, the camera shake detection means 21 and 22 are configured to detect the angular velocity caused by the camera shake, and the reference level corresponding to zero angular velocity is calculated. The reference level calculating means 2 is configured to do so. According to a fourth aspect of the present invention, in the image stabilization camera according to any one of the first to third aspects, a storage unit 20 that stores a value relating to a predetermined time is provided, and the image stabilization units 21 and 21 are provided.
The control means 2 is configured to read the value regarding the predetermined time stored in the storage means 20 before the detection by 2 is started.

[0006]

In the invention described in claim 1, the camera shake detection means 2
After a lapse of a predetermined time from the start of detection by 1 and 22, the control unit 2 causes the camera shake correction unit 102 to start correction. According to the second aspect of the present invention, after the reference level for detecting the camera shake is calculated by the reference level calculating means 2, the control means 2 starts the correction by the camera shake correcting means 102. According to the third aspect of the present invention, the angular velocity caused by the camera shake is detected by the camera shake detection means 21 and 22, and the reference level corresponding to zero angular velocity is calculated by the reference level calculation means 2, and then the control means 2 is used.
Starts the correction by the camera shake correction means 102. According to the invention described in claim 4, the information about the predetermined time stored in the storage means 20 is read by the control means 2 before the detection by the camera shake detection means 21, 22 is started.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

1 is a block diagram of an embodiment of a camera shake correction camera according to the present invention. Reference numeral 1 denotes a photographing lens group, which is composed of four lenses. Of these, 101 is a focus lens that can move on the optical axis, and 102 is a camera shake correction lens (hereinafter, referred to as a correction lens) that can move in the illustrated X-axis (horizontal) direction and Y-axis (vertical) direction. A shutter 103 is arranged in front of the correction lens 102.
2 is C for detecting the amount of camera shake and controlling the movement of the correction lens.
It is PU. The CPU 2 is composed of a one-chip microcomputer in which a timer, an A / D converter, a counter, and the like are integrated, and controls the entire sequence of the camera.

Reference numeral 3 is a motor for opening and closing the shutter, 4 is a motor for moving the correction lens in the X-axis direction, 5 is a motor for moving the correction lens in the Y-axis direction, and 6 is a motor for moving the focus lens in the optical axis direction. is there. Reference numerals 7 to 10 are motor drive circuits for driving the motors 3 to 6, respectively. The motor drive circuits 7 to 10 drive the motors 3 to 6 by so-called duty drive in which the pulse width is changed according to the motor drive amount. At this time, the drive direction signal and the drive duty signal are input from the CPU 2 to the motor drive circuits 7 to 10. The drive direction signal indicates the drive direction of the motors 3 to 6, and the drive duty signal indicates the drive amount of the motors 3 to 6. The rotation of each of the motors 3 to 6 is converted into a linear motion by a correction lens driving mechanical system (not shown), whereby the correction lens 102 is a two-axis X-axis orthogonal to the optical axis of the photographing lens group 1, Move in the Y-axis direction.

Reference numeral 11 designates a photometric circuit for measuring the subject brightness.
2 is a focus control information detection circuit for detecting focus control information, 1
Reference numeral 3 is a shake indicator for displaying the shake condition. Reference numeral 14 is a main switch for supplying power to each part of the camera, 15 is a half-push switch that is turned on by half-pressing a release button (not shown), and 16 is a release switch that is turned on by fully-pressing the release button. Once the main switch 14 is set to the on position or the off position, it holds that state. On the other hand, when the release button is operated, the half-push switch 15 or the release switch 16 is turned on only while the release button is being operated.

Reference numeral 17 is a lens position detection circuit for detecting the position of the correction lens in the X-axis direction, 18 is a lens position detection circuit for detecting the position of the correction lens in the Y-axis direction, and 19 is a lens position for detecting the position of the focus lens. It is a detection circuit.
Each of the lens position detection circuits 17 to 19 outputs a pulse corresponding to the amount of movement of each lens, and the CPU 2 measures the number of pulses to detect the position and amount of movement of each lens. Further, the moving speed of each lens is detected by the moving amount in a predetermined time unit.

Reference numeral 20 denotes an EEPROM for storing data such as adjustment values necessary for photographing processing, and the CPU 2 reads the stored contents as needed. Reference numeral 21 is an angular velocity detection circuit for detecting the angular velocity due to camera shake in the X-axis direction, and 22 is Y
It is an angular velocity detection circuit that detects an angular velocity due to camera shake in the axial direction. The outputs of the angular velocity detection circuits 21 and 22 change according to the magnitude of the angular velocity. Generally, the higher the angular velocity, the larger the output amplitude.

FIG. 2 is a circuit diagram of an embodiment of the angular velocity detecting circuits 21 and 22. In FIG. 2, 201 is an angular velocity sensor that detects an angular velocity caused by camera shake, and 202 is a low-pass filter that removes high-frequency component noise included in the output of the angular velocity sensor 201. Reference numeral 203 denotes a high-pass filter and amplifier that removes low-frequency component noise included in the output of the low-pass filter 202 and amplifies the output of the low-pass filter 202. The capacitor C and the resistor R1 inside the high pass filter & amplifier 203 form a high pass filter, and the operational amplifier OP forms an amplifier. The output of the operational amplifier OP is input to the CPU 2 shown in FIG. An analog switch SW is connected to one input terminal of the operational amplifier OP for the purpose of reducing the offset value of the operational amplifier output.

FIG. 3 is a flow chart showing the main processing by the CPU 2. When the main switch 14 is turned on, the CPU 2 starts the processing of this flowchart. In step S1 of FIG. 3, the registers and the like inside the CPU 2 are initialized. In step S2, it is determined whether the half-push switch 15 is on. If the determination is positive, step S
3, the photographing process of FIG. 4 described later is performed, and step S
Go to 4. If the determination in step S2 is negative, the process proceeds to step S4 and it is determined whether or not the main switch 14 is on. If the determination is affirmative, the process returns to step S2, and if the determination is negative, the process ends.

4 and 5 are flow charts showing the details of the photographing process in step S3 of FIG. Step S in FIG.
At 11, a battery check is performed. That is, the voltage value of the battery (not shown) is measured, and it is determined whether or not the voltage value is an operable voltage. In order to accurately measure the voltage value of the battery, it is desirable to measure with the load applied to the battery. Therefore, for example, the battery voltage is measured with the motor drive circuit 7 driven. This step S1
When the determination of 1 is denied, the process returns, and when the determination is affirmed, the process proceeds to step S12. In step S12, the angular velocity detection circuits 21 and 22 are activated. As a result, the angular velocity detection circuits 21 and 22 output the angular velocity signals corresponding to the camera shake. In step S13, timer measurement is started. In this timer, the voltage level (hereinafter,
The time until the zero angular velocity zero voltage is calculated (hereinafter referred to as zero angular velocity calculation time) is measured. The zero angular velocity calculation time is obtained by experiments or the like and is, for example, about 900 ms. Note that the zero angular velocity voltage is obtained here because an accurate angular velocity can be obtained by subtracting the zero angular velocity voltage from the output voltage of the angular velocity detection circuits 21 and 22.

In step S14, the flag is initialized to "0". This flag indicates whether or not the timer described above has timed up (e.g., 900 ms has elapsed), and changes from "0" to "1" when the time is up. In step S15, a signal is sent to the photometric circuit 11,
Start photometric processing. In step S16, a signal is sent to the focus adjustment information detection circuit 12 to start focus detection processing. In step S17, AE calculation is performed based on the photometric result to obtain the aperture value and shutter speed. In step S18, FM calculation is performed based on the focus detection result to obtain a shootable distance when the electronic flash device is used.

In step S19, the angular velocity detection circuit 2
To secure the time for the outputs of 1 and 22 to stabilize, (1)
The wait time (hereinafter, referred to as the angular velocity detection circuit stabilization time) T1 is calculated based on the equation, and only this time is step S19.
Stay in.

## EQU1 ## T1 = 300 ms− (photometry processing time + focus adjustment information detection time) (1) In this step S19, the angular velocity detection circuits 21 and 22 are irrespective of the time required for photometry and focus adjustment information detection.
Wait until 300ms has passed after starting. Thereby, for example, even if the forced infinite mode or the long time mode is selected and the photometry process or the focus detection process is completed in a short time, 300 ms after the power is supplied to the angular velocity detection circuits 21 and 22, step S19 is performed. Subsequent processing is performed.

In step S20, the focus lens 101 is moved based on the focus detection result of step S16. The time required to move the focus lens 101 is about 100 ms. In step S21, the amount of camera shake is calculated based on the outputs of the angular velocity detection circuits 21 and 22,
A signal according to the amount of camera shake is sent to the shake state indicator 13. As a result, the shake-state indicator 13 displays according to the amount of shake. Specifically, for example, the blinking speed of the LED inside the shake state indicator is changed according to the amount of shake.

In step S22, it is determined whether the flag is "1". If the determination is negative, the process proceeds to step S23, and it is determined whether or not the timer has timed out. If the determination is positive, the process proceeds to step S24, and the flag is set to "1".
And set to step S25. On the other hand, step S
If the determination of 22 is affirmative or the determination of step S23 is negative, the process proceeds to step S25,
It is determined whether the release switch 16 is on. If the determination is negative, the process proceeds to step S26, and the halfway press switch 1
It is determined whether or not 5 is on. If the determination is affirmative, the process proceeds to step S27, and after the hand shake display of the shake state indicator 13 is updated based on the outputs of the angular velocity detection circuits 21 and 22,
It returns to step S22.

If the determination in step S26 is negative, the process proceeds to step S28, in which a signal is sent to the angular velocity detection circuits 21 and 22 to stop the angular velocity detection. In step S29,
It is determined whether the flag is "1". If the determination is negative, the process proceeds to step S30, the timer measurement is stopped, and the process proceeds to step S31. When the determination in step S29 is affirmative, the process proceeds to step S31, the display of the shake state indicator 13 is turned off, and the process returns.

On the other hand, if the determination in step S25 is affirmative, the flow advances to step S32 in FIG. 5 to determine whether or not the self mode is set. The self-mode is a mode in which the shutter 103 is operated after the time specified by the self-timer elapses after the release switch 16 is turned on.

If the determination in step S32 is negative, the process proceeds to step S33 and it is determined whether or not the red-eye mode is set. The red eye means that the light of the electronic flash device is reflected by the capillaries of the fundus of the subject person to photograph the eye red. For this reason,
The red-eye mode is one in which weak light is emitted from the electronic flash device to the subject person before exposure (hereinafter referred to as pre-emission) to close the pupil and then exposure is performed. When this red-eye mode is selected, the process proceeds to step S34, and pre-emission for 1 second before exposure is performed. If the red-eye mode is not selected, the process proceeds to step S35, and a wait is applied until the shake caused by pressing the release button disappears. Hereinafter, this wait time is referred to as shock avoidance time T2. Here, the shock avoidance time T2 is provided because the camera shake when the release button is pressed is temporary, and moving the correction lens 102 during this period does not mean that the camera shake during exposure is corrected. This is because. Further, since the correction lens 102 is moved unnecessarily and the battery is consumed wastefully, the camera shake correction process is started after the shock avoidance time has elapsed. On the other hand, when the determination in step S32 is affirmative, the process proceeds to step S36, and the timer measurement is performed for the time designated in advance by the self-timer.

When the processes of steps S34 to S36 are completed, the process proceeds to step S37 to turn off the display of the shake display unit 13. In step S38, it is determined whether the flag is "1". When the determination is negative, the process proceeds to step S39 and it is determined whether or not the timer has timed out. If the determination is negative, the process stays in step S39, and if the determination is affirmative, the process proceeds to step S40. The determinations in steps S38 and S39 are provided in order to perform the camera shake correction processing in step S40 and subsequent steps after the zero angular velocity voltage is obtained. The calculation of the zero angular velocity voltage is performed in the timer interrupt process by, for example, issuing a timer interrupt to the CPU 2 every predetermined time.

If the determination in step S38 is affirmative, the flow advances to step S40 to move the correction lens from the reset position to the optical axis of the photographing lens group 1. In step S41, the camera shake correction process is started. Specifically, based on the outputs of the angular velocity detection circuits 21 and 22 and the calculated zero angular velocity voltage, the true angular velocity corresponding to the amount of camera shake is calculated, and the movement amount of the correction lens is calculated based on this, to drive the motor. The drive direction signal and the drive duty signal are sent to the circuits 8 and 9.

In step S42, the time until the movement of the correction lens 102 stabilizes (hereinafter, referred to as run-up control time) T3 is waited. That is, immediately after the camera shake correction process is started, the correction lens 10 is caused by the signal delay of the motor drive circuits 8 and 9 and the vibration of the correction lens drive mechanical system.
Since the movement of 2 is unstable, opening and closing the shutter 103 in such a state may result in a captured image with large blur. Therefore, the approach control time is provided to open and close the shutter 103 after the movement of the correction lens 102 is stabilized. This run-up control time is, for example, about 20 ms.

In step S43, a shutter opening process for opening the shutter 103 is performed. And the above-mentioned AE
After the lapse of the predetermined time calculated by the calculation, the process proceeds to step S44, and the shutter closing process for closing the shutter 103 is performed. In step S45, the camera shake correction process is stopped. That is, the signal transmission to the motor drive circuits 8 and 9 is stopped, and the correction lens 102 is stopped. In step S46, a signal is sent to the angular velocity detection circuits 21 and 22 to stop the angular velocity detection. In step S47, the correction lens 102 is retracted to the reset position. In step S48, the focus lens 101 is retracted to the reset position. In step S49, a signal is sent to a film feeding circuit (not shown) to wind up the film and return.

As described above, according to the above-described embodiment, when the release button is half-pressed, the battery voltage is first measured, and the camera shake detection process is not performed when the battery voltage value is less than the predetermined value. The problem that the accuracy of camera shake detection is reduced due to the low voltage is avoided. On the other hand, when the battery voltage value is equal to or higher than the predetermined value, the camera shake detection process is continuously performed.
The camera shake detection process can be started before the focus adjustment information detection process is performed. Further, since the amount of camera shake is displayed after a predetermined time T1 has elapsed after starting the angular velocity detection process, it is possible to avoid displaying the amount of camera shake when the outputs of the angular velocity detection circuits 21 and 22 are unstable. The reliability of the shake display on the display 13 is improved.

Further, since the hand-shake correction process is started after the predetermined time T2 has elapsed after the release button was fully pressed, the hand-shake correction process is not performed even if a temporary hand-shake occurs due to the release button being pressed. The power consumption of the battery can be reduced. Furthermore, after activating the angular velocity detection circuits 21 and 22, a predetermined time, for example, 900 m
Since the camera shake correction process is started after s has elapsed, a zero angular velocity voltage corresponding to zero angular velocity is obtained,
The shake correction process can be performed after the true angular velocity is obtained based on the value, and the accuracy of the shake correction process is improved. Further, since the shutter 103 is opened and closed to perform the exposure process after the lapse of a predetermined time T3 from the start of the camera shake correction process, it is possible to avoid the influence of blurring or the like at the initial driving of the correction lens 102.

The angular velocity detection circuit stabilization time T1, the shock avoidance time T2, the approach control time T3 and the zero angular velocity calculation time of the above embodiment are stored in the EEPROM 20, and the CPU 2 executes the initialization process of step S1 of FIG. Each time may be read when performing. Alternatively, several kinds of each of the above times may be prepared so that the photographer can select from among them, or each time can be freely changed. In the above example,
When the voltage value of the battery is smaller than the predetermined value, the shooting process is stopped, but only the camera shake detection process and the camera shake correction process, which consume a lot of battery power, are stopped, and the photometry process and the focus adjustment information detection process are not performed. It may be performed.

In the photographing process of FIGS. 4 and 5, the camera shake detection process is performed after the battery check, but the camera shake detection process may be immediately performed by half-pressing the release button without performing the battery check. In the above example,
Although the example in which the angular velocity detection circuit detects the angular velocity caused by camera shake is shown, a sensor circuit for detecting acceleration other than the angular velocity, a position change, or the like may be provided instead of the angular velocity detection circuits 21 and 22. In the image capturing process of FIGS. 4 and 5, camera shake display is performed after the angular velocity detection circuit stabilization time T1 has elapsed, but the timer for measuring the zero angular velocity calculation time waits until the time expires, and after the time is up, camera shake display is performed. You may go. As a result, the reliability of the shake display is further improved. As the focus detection method of the focus adjustment information detection circuit of the above embodiment, various methods such as a method based on a distance measuring method for measuring a subject distance and a method based on a focus detection method for examining the state of the focal plane of the photographing lens are available. Applicable.

In the embodiment constructed as described above,
The angular velocity detection circuits 21 and 22 serve as camera shake detection means, the correction lens 102 serves as camera shake correction means, and step S38 in FIG.
~ S45 corresponds to the control means, the CPU2 corresponds to the reference level calculation means, and the EEPROM 20 corresponds to the storage means.

[0032]

As described in detail above, according to the present invention, since the shake correction is started after a predetermined time has elapsed after the start of the shake detection, the shake is detected during the predetermined time. It is possible to calculate the reference level for the calculation, and as a result, it is possible to detect the true shake amount. Therefore, by performing the camera shake correction based on the detected camera shake amount, the accuracy of the camera shake correction can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of an image stabilization camera according to the present invention.

FIG. 2 is a circuit diagram of an embodiment of the angular velocity detection circuit shown in FIG.

FIG. 3 is a flowchart showing a main process of the CPU shown in FIG.

FIG. 4 is a flowchart showing a photographing process of the CPU shown in FIG.

FIG. 5 is a flowchart following FIG.

[Explanation of symbols]

 1 Photographic lens group 2 CPU 3-6 Motor 7-10 Motor drive circuit 11 Photometric circuit 12 Focus adjustment information detection circuit 13 Shake state indicator 14 Main switch 15 Half-press switch 16 Release switch 17-19 Lens position detection circuit 20 EEPROM 21 , 22 Angular velocity detection circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Nakamura 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Inside Nikon Corporation

Claims (4)

[Claims] 1. A camera shake correction camera comprising: a camera shake detection means for detecting camera shake generated in a camera; and a camera shake correction means for correcting at least the detected camera shake during exposure. An image stabilization camera, comprising: a control unit that starts the correction by the image stabilization unit after a predetermined time has elapsed after the detection by the camera was started. 2. The camera shake correction camera according to claim 1, further comprising: reference level calculation means for calculating a reference level for detecting camera shake based on the output of the camera shake detection means. A camera shake correction camera, wherein correction by the camera shake correction means is started after the reference level is calculated. 3. The camera shake correction camera according to claim 2, wherein the camera shake detection unit detects an angular velocity caused by the camera shake, and the reference level calculation unit calculates a reference level corresponding to zero angular velocity. An image stabilization camera featuring. 4. The camera shake correction camera according to claim 1, further comprising storage means for storing a value relating to the predetermined time, wherein the control means starts detection by the camera shake detection means. A camera shake correction camera, characterized in that a value relating to the predetermined time stored in the storage means is read in advance.