JP2010145833A - Vibration detecting device, and optical apparatus with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration detecting device having enhanced detection accuracy by reducing drift components having no relation with a true angular displacement amount. <P>SOLUTION: AD conversion of the output of a vibration detecting means and AD conversion of a voltage proportional to that for power supply of the vibration detecting means are separately performed, and a difference between respective AD conversion results is regarded as a true vibration signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration detection device for detecting vibration of a photographing equipment and the like and an optical apparatus having the same.

  In recent years, an optical device such as a camera or an interchangeable lens is equipped with an image stabilization system that controls image blur due to camera shake or the like in order to obtain a good captured image.

  Camera shake is usually vibration having a frequency of about 1 Hz to 10 Hz, and the anti-vibration system performs the following correction in order to take a photograph free from image blur. First, a vibration for the optical device is detected, and an operation for converting the detection result into a signal for correcting image blur is performed. Depending on the calculation result, the correction lens is driven in the plane orthogonal to the optical axis (optical image stabilization), or the area to be cut out of the captured image is shifted (electronic image stabilization) to control the optical axis change due to image blurring. is doing.

  FIG. 8 is a diagram showing an image blur correction effect for each frequency in the above-described image stabilization system. The horizontal axis indicates the frequency, and the vertical axis indicates how much image blur remaining amount on the imaging surface is obtained by performing the image blur correction when the time when no image blur correction is performed is 100%. Usually, it has a peak near a certain frequency (for example, 5 Hz), and the anti-vibration effect decreases as the frequency becomes lower and higher than that. This characteristic depends mainly on the characteristics of the filter (for example, the integration filter) used to convert the output from the sensor that detects vibration into a signal for correcting the image blur and the characteristics of the correction system that actually corrects the blur. Determined. In order to further improve the anti-vibration effect, it is necessary to improve the low frequency and high frequency characteristics by improving the filter characteristics. In particular, a blur having a larger amplitude than a blur generated in the “hand” such as a blur of a human body has a high ratio of low-frequency components, and improvement of the low-frequency characteristics is effective for enhancing an anti-vibration effect.

  In order to detect vibration, specifically, vibration is detected using an acceleration sensor, an angular velocity sensor, or the like, and blur information of the optical device, that is, an angular displacement amount is obtained by calculation processing based on the detection result.

An acceleration sensor, an angular velocity sensor, or the like is used as a vibration detection unit that detects vibration applied to a certain device. Conventionally, the acceleration sensor and the angular velocity sensor have a problem that the sensor output drifts due to various factors such as temperature, humidity, power supply voltage fluctuation, and initial fluctuation when the power is turned on. In order to solve this problem, for example, Patent Document 1 discloses a method of removing a drift component by providing a drift detection unit in a sensor and taking a difference from the vibration detection unit. Furthermore, in order to suppress the above-mentioned various factors of variation, a contrivance has been made to suppress drift of the sensor itself by using a highly stable crystal oscillator for the sensor.
JP-A-4-269622

  However, there remains a drift component that cannot be completely removed by the device itself. Furthermore, when using the acceleration sensor or the angular velocity sensor described above, an integration process must be performed in order to calculate the angular displacement amount. As described above, the low frequency characteristics of the integration filter are required to improve the detection accuracy. As a result, the drift component is further amplified. For example, even if the sensor output fluctuation on the order of μV occurs due to the fluctuation of the power supply voltage, it will appear as a large angular displacement. Further, when the reference voltage of the AD converter for AD converting the sensor output varies on the order of μV, the result of AD conversion of the sensor output can be a factor of variation. In order to solve these problems, it is possible to take measures such as placing a high-performance regulator in the power supply and tightening the wiring on the mounting, but this increases power consumption and costs. .

  The present invention has been made in view of the above problems, and reduces the drift component irrelevant to the true angular displacement of the optical device from the output of the vibration detection means for detecting the vibration of the optical device, thereby improving the detection accuracy. Another object of the present invention is to provide a vibration detecting apparatus and an optical apparatus having the same.

  In order to achieve the above object, according to the present invention, the vibration detection means for detecting vibration, the power supply means for supplying power to the vibration detection means, and the output of the vibration detection means are as described in claim 1. A signal processing means for performing signal processing in analog; an AD conversion means for converting an input analog signal into a digital signal; and a first converted signal obtained by performing AD conversion on the output of the signal processing means by the AD conversion means; A difference calculating means for calculating a difference from a second conversion signal obtained by AD converting the voltage proportional to the voltage supplied from the power supply means to the vibration detecting means by the AD converting means. is there.

  In addition, as described in claim 2, vibration detection means for detecting vibration, power supply means for supplying power to the vibration detection means, and signal processing means for performing signal processing on the output of the vibration detection means in an analog manner AD conversion means for converting an input analog signal into a digital signal and outputting; an integration means for integrating the output of the AD conversion means; and an output of the signal processing means subjected to AD conversion by the AD conversion means A first integrated signal obtained by further integrating the first converted signal by the integrating means and a voltage proportional to the voltage supplied from the power supply means to the vibration detecting means by AD conversion by the AD converting means. And a difference calculating means for calculating a difference between the converted signal and the second integrated signal integrated by the integrating means.

  According to the present invention, in an image blur correction apparatus for an optical device, vibration detection is performed by reducing a drift component unrelated to the true angular displacement of the optical device from an output of a vibration detection unit that detects vibration, and improving detection accuracy. It is possible to provide an apparatus and an optical apparatus having the apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram of an image blur correction apparatus using the vibration detection apparatus according to the first embodiment. Reference numeral 1 denotes a signal power supply that supplies power to the CPU 2, the regulator 3, and the regulator 5. Reference numeral 2 denotes a CPU that performs calculations for image blur correction. A regulator 3 is a power supply means for stepping down the voltage of the signal system power supply 1 and supplies power to the gyro 4, and a regulator 5 is a regulator for supplying a reference voltage for the AD converter in the CPU 2. Reference numeral 6 denotes a switch for switching a voltage supplied to the regulator 3, and reference numeral 7 denotes power supply control means provided in the CPU 2 for controlling the switch 6. The power supply control means 7 turns off the switch 6 when camera shake correction is not performed, so that extra power is not consumed. A signal processing unit 8 multiplies the output signal of the gyro 4 by a low-pass filter and a predetermined gain. Reference numeral 10 denotes a voltage dividing means for dividing the output of the regulator 3. Reference numeral 9 denotes an AD converter provided in the CPU 2, and the output of the signal processing means 8 is channel 1, and the output of the regulator 3 that is divided by the voltage dividing means 10 and proportional to the voltage applied to the gyro 4 is channel 2. A / D conversion is performed at Reference numeral 11 denotes gain calculation means for multiplying a predetermined gain by the voltage-divided signal (second conversion signal) of the regulator 3 subjected to AD conversion in the channel 2. Reference numeral 12 denotes a difference calculation means for calculating the difference between the channel 1 signal after AD conversion (first conversion signal) and the output of the gain calculation means 11. Reference numeral 13 denotes a high-pass filter for cutting low-frequency components of the output of the difference calculation means 12, reference numeral 14 denotes an integrator for integrating the output of the high-pass filter, and reference numeral 15 denotes target position calculation means for converting the integration output into a target position. It is. Reference numeral 16 denotes a blur correction lens for correcting image blur, and reference numeral 17 denotes a position detection means for detecting the position of the blur correction lens 16. The output of the position detection means 17 is AD converted by the AD converter 9, a difference from the target position is taken by the difference calculation means 18, multiplied by a predetermined gain by the gain calculation means 19, and the correction lens drive signal is sent to the correction lens drive means 20. Is entered as Here, only the state of signal processing of one rotation axis direction detection axis is shown, but the same is true for the other side. In addition, although only three channels are displayed for the AD converter, at least the other detection axis can be covered.

  FIG. 2 is a diagram showing the relationship between the gyro signal and the influence of each regulator in the angular velocity region. (A) represents an angular velocity, and for the sake of explanation, a camera shake signal having a frequency of 5 Hz and an amplitude of about ± 3 deg / sec is assumed here. (B) represents the influence of fluctuations in the output voltage of the regulator 3 in FIG. 1 on the AD conversion result of the gyro signal. Similarly, (c) represents the influence of fluctuations in the output voltage of the regulator 5 on the AD conversion result of the gyro signal. When the gyro signal is AD-converted, the conversion result shown in (d) including the effects of (b) and (c) is obtained in addition to the angular velocity (a) due to pure camera shake. Here, all waveforms are displayed as sine waves for convenience of explanation, and actual waveforms are not limited thereto.

  FIG. 3 shows the result of integrating each signal of FIG. The integration result of (a) is (a ′), the integration result of (b) is (b ′), the integration result of (c) is (c ′), and the integration result of (d) is (d ′). It corresponds to. When (b) and (c) with small amplitudes are integrated at a low frequency, it can be seen that the influence appears more prominently.

  In the configuration of FIG. 1, the conversion result of channel 1 obtained by AD converting the output of the signal processing means 8 corresponds to the signal (d) in FIG. 2, that is, (a) + (b) + (c ).

  Further, the output of the gain calculation unit 11 obtained by multiplying the conversion result of the channel 2 obtained by AD-converting the output of the voltage dividing unit 10 corresponds to (b) + (c) in FIG. Therefore, the output of the difference calculation means 12 is (d) − (b) − (c) = (a), and becomes an angular velocity component from which the voltage fluctuation of each regulator is removed.

  As described above, in this embodiment, in the image blur correction apparatus for an optical apparatus, the drift component unrelated to the true angular displacement of the optical apparatus is reduced from the output of the vibration detection means for detecting vibration, and the detection system It is possible to provide a vibration detection device with improved resistance.

  Example 2 will be described. FIG. 4 is a block diagram of an image blur correction apparatus using the vibration detection apparatus according to the second embodiment. Those having the same roles as those in the first embodiment are given the same numbers, and descriptions thereof are omitted. Reference numeral 21 denotes a high-pass filter for cutting the low-frequency component of the channel 1 signal after AD conversion, and reference numeral 22 denotes an integrator for integrating the output of the high-pass filter 21. Reference numeral 23 denotes a high-pass filter for cutting the low-frequency component of the output of the gain calculation means 11, and reference numeral 24 denotes an integrator for integrating the output of the high-pass filter 23. Reference numeral 25 denotes difference calculation means for calculating the difference between the output of the integrator 22 (first integration signal) and the output of the integrator 24 (second integration signal).

  In the configuration of FIG. 4, the output of the integration means 22 corresponds to the signal (d ′) in FIG. 4, that is, (a ′) + (b ′) + (c ′). The output of the integrating means 24 corresponds to (b ′) + (c ′) in FIG. Therefore, the output of the difference calculation means 25 is (d ′) − (b ′) − (c ′) = (a ′), which is an angular displacement component from which the voltage fluctuation of each regulator is removed.

  As described above, in this embodiment, in the image blur correction apparatus for an optical apparatus, the drift component unrelated to the true angular displacement of the optical apparatus is reduced from the output of the vibration detection means for detecting vibration, and the detection system It is possible to provide a vibration detection device with improved resistance.

Example 3 will be described. FIG. 5 is a block diagram of an image blur correction apparatus using the vibration detection apparatus according to the third embodiment. The difference from the first embodiment is that the regulator used for the gyro power supply and the regulator used for the reference voltage of the AD converter are made common. In this case (what are the benefits)
In this embodiment, the conversion result of channel 1 obtained by AD conversion of the output of the signal processing means 8 corresponds to the signal (a) + (b) in FIG. Further, the output of the gain calculation means 11 obtained by multiplying the conversion result of the channel 2 obtained by AD converting the output of the voltage dividing means 10 corresponds to (b) in FIG. Therefore, the output of the difference calculation means 12 becomes (a) + (b) − (b) = (a), and becomes an angular velocity component from which the voltage fluctuation of the regulator 26 is removed.

  As described above, in this embodiment, in the image blur correction apparatus for an optical apparatus, the drift component unrelated to the true angular displacement of the optical apparatus is reduced from the output of the vibration detection means for detecting vibration, and the detection system It is possible to provide a vibration detection device with improved resistance. Further, in the configuration of this embodiment, the number of regulators can be reduced, so that the cost is lower than that of the other embodiments.

  As mentioned above, although each Example was described, this invention is not limited to the Example mentioned above. For example, the signal processing unit 8 may have a high-pass filter function, and the offset may be removed before AD conversion.

  Further, the signal processing means 8 may be provided in the CPU as an analog circuit preceding the AD converter.

  If the detection range of the AD converter is sufficiently wide, the gyro power supply voltage may be directly AD converted without using the voltage dividing means 10.

  Further, the regulator may not be used as the power source for the gyro, and the same power source as the CPU may be directly used as the power source for the gyro.

  An acceleration sensor may be used instead of the gyro. At that time, in order to convert acceleration into a position signal, it is necessary to perform second order integration.

  Further, the blur correction unit may be a type that drives a correction lens, a type that drives an image sensor, or an electronic image stabilization type that shifts an area to be cut out of a captured image.

  Further, the control method of the blur correction unit may be feedback control or open control.

1 is a block diagram of an image blur correction apparatus according to a first embodiment. Diagram showing the relationship between the gyro signal and the influence of each regulator in the angular velocity region Diagram showing the relationship between the gyro signal and the influence of each regulator in the angular displacement area Block diagram of the image blur correction apparatus of the second embodiment Block diagram of an image blur correction apparatus according to Embodiment 3 Diagram showing image blur correction effect for each frequency

Explanation of symbols

1 Power supply for signal system 2 CPU for performing image blur correction
DESCRIPTION OF SYMBOLS 3 Regulator 4 Gyro 5 Regulator 6 Switch 7 Power supply control means 8 Signal processing means 9 AD converter 10 Voltage dividing means 11 Gain calculating means 12 Difference calculating means 13 High pass filter 14 Integrator 15 Target position calculating means 16 Shake correction lens 17 Position detection Means 18 Difference computing means 19 Gain computing means 20 Correction lens driving means 21 High pass filter 22 Integrator 23 High pass filter 24 Integrator 25 Difference computing means 26 Regulator

Claims (4)

A vibration detection device used in an image blur correction device for correcting image blur caused by vibration applied to an optical device,
Vibration detecting means for detecting the vibration;
Power supply means for supplying power to the vibration detection means;
Signal processing means for performing analog signal processing on the output of the vibration detection means;
AD conversion means;
A first conversion signal obtained by AD conversion of the output of the signal processing means by the AD conversion means and a voltage proportional to a voltage supplied from the power supply means to the vibration detection means are AD converted by the AD conversion means. And a difference calculating means for calculating a difference between the two converted signals. A vibration detection device used in an image blur correction device for correcting image blur caused by vibration applied to an optical device,
Vibration detecting means for detecting the vibration;
Power supply means for supplying power to the vibration detection means;
Signal processing means for performing analog signal processing on the output of the vibration detection means;
AD conversion means;
Integrating means for integrating the output of the AD converting means;
A first converted signal obtained by AD converting the output of the signal processing means by the AD converting means, and a voltage supplied from the power supply means to the vibration detecting means; Difference calculating means for calculating a difference between the second converted signal obtained by AD conversion of the voltage proportional to the second converted signal by the AD converting means and the second integrated signal integrated by the integrating means;
A vibration detection apparatus comprising:   The vibration detection apparatus according to claim 1, wherein the power supply unit supplies a reference voltage to the AD conversion unit.   An optical apparatus comprising the vibration detection device according to claim 1.

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