JP5258222B2 - Camera with shake correction function - Google Patents

Description

  The present invention relates to a photographing apparatus with a blur correction function for detecting image blur caused by vibration of a photographing apparatus such as a video camera or a still camera and reducing the image blur.

  2. Description of the Related Art In recent years, photographing apparatuses are remarkably advanced in automation and computerization including autofocus and automatic exposure. Among them, photographing apparatuses having a shake correction function that detects vibrations such as camera shake occurring during photographing and reduces image shake are becoming popular.

  On the other hand, with the widespread use of mobile phones, wireless LANs, and the like, there are increasing opportunities for the photographing apparatus to be exposed to these radio waves, and there is a possibility that the shake correction function malfunctions due to such electromagnetic waves.

  Angular velocity sensors and acceleration sensors are used as sensors for detecting the vibrations of equipment, but these sensors detect vibrations with weak signals, so they are vulnerable to disturbances such as electromagnetic waves and strong impacts. have. Patent Document 1 proposes a device that includes an angular velocity sensor and an acceleration sensor arranged adjacent to the angular velocity sensor, and determines an erroneous output of the gyro sensor from the signal of the acceleration sensor.

JP 2004-294335 A

  Conventionally, in order to protect the vibration detection sensor from disturbance due to electromagnetic waves, the sensor is protected by a conductive member, a high permeability member, or a radio wave absorber. In such a mechanistic measure, it is necessary to add a dedicated shield part, which increases the cost. In addition, if there are two types of shake detection sensors as in Patent Document 1, it is possible to grasp the abnormal state of each sensor. However, in the photographing apparatus, vibration may be detected by one type of shake detection sensor. Many are not practical.

  An object of the present invention is to solve the above-described problems and provide an imaging apparatus with a shake correction function that can perform normal image shake correction even when an abnormal signal is detected.

Technical characteristics of the shake correcting function imaging apparatus according to the present invention in order to solve the above problems, the vibration signal detecting means for detecting a vibration signal, from said vibration signal detecting means for detecting a signal relating to another lens control a signal detecting means, and the abnormal signal detecting means for detecting an abnormality signal superimposed on the vibration signal detecting means and the signal detecting unit, and a shake correction characteristic changing means changes the shake correction characteristics, the abnormal signal detecting means When the abnormal signal is detected in the output from the shake signal detecting means and the output from the signal detecting means , the shake correction characteristic changing means changes the shake correction characteristic according to a focal length. To do.

  According to the photographing apparatus with a shake correction function of the present invention, it is possible to detect an abnormality of a device due to an electromagnetic wave or the like using an existing sensor used for lens control, and to reduce an abnormal operation of shake correction. Can do. In addition, since the abnormal signal is detected by a plurality of sensors, the detection accuracy of the abnormal signal can be improved and there is no erroneous detection.

  The present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 is a block circuit configuration diagram of a shake correction function according to the first embodiment. In FIG. 1, a variable apex angle prism 1, a fixed front lens unit 2, a zoom lens unit 3 that moves in the optical axis direction and performs zooming, and a diaphragm unit 4 that adjusts the amount of light are arranged along the optical axis. . Arranged behind the aperture unit 4 are a fixed lens unit 5, a focus lens unit 6 that moves in the optical axis direction to adjust the focus, and an image sensor 7 that includes a CCD sensor, a CMOS sensor, or the like. The output of the image sensor 7 is connected to the display device VTR via the video signal processing circuit 8.

  The output of the gyro sensor 9 that detects the angular shake of the photographing apparatus is connected to the panning control unit 12 and the variable HPF (high pass filter) 13 via the DC cut filter 10 and the amplifier 11, and the output of the panning control unit 12 is variable. It is connected to the HPF 13. The output of the variable HPF 13 is connected to the subtracter 16 via the phase / gain compensation unit 14 and the integration processing unit 15. The output of the integration processing unit 15 is also connected to the panning control unit 12. The other end of the subtractor 16 is connected to the output of an encoder 17 that detects the displacement of the variable apex angle prism 1 via a signal processing circuit 18 and an amplifier 20. The output of the subtracter 16 is connected to the actuator 23 of the variable apex angle prism 1 through the phase / gain compensation unit 21 and the drive circuit 22.

  The light flux from the subject passes through the variable apex prism 1 and the lens unit 2, the zoom lens unit 3, the aperture unit 4, the fixed lens unit 5, and the focus lens unit 6, and forms an image on the light receiving surface of the image sensor 7. . The image sensor 7 accumulates the photoelectrically converted charges and reads the charges at a predetermined timing. The signal output from the image sensor 7 is sent to the video signal processing circuit 8, and the video signal is generated by performing various processes such as predetermined amplification and gamma correction on the output signal from the image sensor 7. It is output to a display device VTR such as a liquid crystal display panel.

  The gyro sensor 9 detects angular velocity shake of the photographing apparatus, and detects vibration of the photographing apparatus physically or mechanically. In this embodiment, the gyro sensor is used, but the vibration of the photographing apparatus may be detected using an acceleration sensor. The DC cut filter 10 having a cutoff frequency of about 0.1 Hz blocks the direct current component of the output signal from the gyro sensor 9 and passes only the vibration component.

  The amplifier 11 amplifies the angular velocity signal output from the DC cut filter 10 to a required level, and the amplified angular velocity signal is input to the variable HPF 13. The variable HPF 13 is used in order to obtain a desired frequency band of the input angular velocity signal whose cutoff frequency is changed by a command signal from the panning control unit 12.

  For example, when the cut-off frequency of the variable HPF 13 is about 0.1 Hz, a shake signal such as hand shake or body shake is passed. When the cutoff frequency is a sufficiently high frequency of 100 Hz or more, the shake signal is not passed, the reference potential of the gyro sensor 9 is output, and the shake correction system is in a centered state. The angular velocity signal that has passed through the variable HPF 13 is input to the phase / gain compensation unit 14, phase compensation and gain setting are performed, and the resultant signal is sent to the integration processing unit 15. The signal that has passed through the integration processing unit 15 becomes an angular displacement signal, and becomes a target angular displacement signal for performing image blur correction.

  The variable apex angle prism 1 performs optical shake correction, and is configured by enclosing a transparent elastic body or inert liquid having a high refractive index between flat glass plates arranged opposite to each other. The optical path is displaced by tilting the flat glass sheet. be able to. A position indicating the apex angle or the optical axis deflection angle of the variable apex angle prism 1 is detected by the encoder 17. The detection signal is converted into a position signal of the same dimension as the output of the integration processing unit 15 by the signal processing circuit 18 and then fed back to the subtracter 16. The output of the subtracter 16 is a deviation value between the target angular displacement signal of the variable apex angle prism 1 and the actual position signal of the variable apex angle prism 1. A signal corresponding to the deviation value is compensated for the phase and gain by the phase / gain compensator 21 and input to the drive circuit 22 as a shake correction control signal. Based on the drive signal from the drive circuit 22, the actuator 23 drives the variable apex angle prism 1 to perform shake correction.

  The panning control unit 12 determines whether the photographing apparatus is panning using the angular velocity signal or the angular displacement signal, and changes the cutoff frequency of the variable HPF 13 according to the determination result. This prevents the variable apex angle prism 1 from hitting the machine end position, reduces the photographer's seasickness phenomenon caused by shooting using shake correction, and performs panning control related to shake correction. Yes.

  FIG. 2 is a block circuit configuration diagram of the aperture control function of the photographing apparatus. The same reference numerals as those in FIG. 1 denote the same members. The output of the video signal processing circuit 8 is connected to the subtracter 32 via the target aperture position setting unit 31, and the output of the aperture operation unit 33 is connected to the target aperture position setting unit 31. On the other hand, the output of the diaphragm position sensor 34 for detecting the diaphragm position of the diaphragm unit 4 is connected to the subtracter 32 via the amplifier 35, and the output of the subtractor 32 is stopped by the phase / gain compensator 36 and the drive circuit 37. It is connected to the actuator 38 of the unit 4.

  As the aperture position sensor 34, for example, a Hall sensor that detects a position by the Hall effect, a variable resistance potentiometer, a detection sensor that uses pulse generation, or the like is used. Since the output of the aperture position sensor 34 is weak, it is amplified by the amplifier 35 and fed back to the subtractor 32. The target aperture position setting unit 31 generates a target aperture position signal so that a desired aperture position is obtained according to the luminance information from the video signal processing circuit 8 or the signal from the aperture operation unit 33. The output of the subtractor 32 is a deviation value between the target aperture position signal of the aperture unit 4 and the actual position signal of the aperture unit 4.

  A signal corresponding to the deviation value is compensated for the phase and gain by the phase / gain compensator 36, and is input to the drive circuit 37 as an aperture control signal for driving the aperture unit 4 to the target position. The actuator 38 drives the aperture unit 4 based on the drive signal from the drive circuit 37 to adjust the light amount.

  FIG. 3 is a block circuit configuration diagram of the abnormal signal detection function and the shake correction operation function at that time. The output of the gyro sensor 9 that detects the vibration of the photographing apparatus as an angular velocity is connected to the DC cut filter 10 and the abnormal signal detector 41. As in FIG. 1, the output of the DC cut filter 10 is connected to an amplifier 11, a variable HPF 13, a phase / gain compensation unit 14, and an integration processing unit 15. The output of the abnormal signal detection unit 41 is connected to a shake correction characteristic changing unit 42 and an aperture position correcting unit 43. The output of the panning control unit 12 is connected to the shake correction characteristic changing unit 42 and the variable HPF 13.

  The output of the zoom operation unit 44 is connected to the shake correction characteristic changing unit 42 via the focal length detection unit 45. Further, the output of the aperture position sensor 34 is connected to an abnormal signal detection unit 41 and an aperture position correction unit 43 via an amplifier 35.

  The abnormal signal detector 41 detects an abnormal signal superimposed by the gyro sensor 9 and the aperture position sensor 34. When an abnormal signal is detected, the shake correction characteristic changing unit 42 stops the shake correction operation or restricts the shake correction operation according to the focal length.

  The focal length information is obtained from the zoom operation unit 44 and the focal length detection unit 45. In addition, when the abnormal signal is large, the aperture position correcting unit 43 erroneously detects the aperture position. Therefore, the aperture position correcting unit 43 performs correction so that photographing can be performed even when the abnormal signal is detected.

  4 to 6 show examples of output waveforms of the gyro sensor 9 and the aperture position sensor 34. FIG. FIG. 4 shows an output waveform in a normal state. The abnormal drift signal of the gyro output signal of the gyro sensor 9 is determined by the threshold value Vm. During the period from time T1 to T2, an abnormal drift signal exceeding the threshold value Vm is generated in the output signal of the gyro sensor 9. However, the output signal of the aperture position sensor 34 is stable at the target value Vt, and no abnormal signal is recognized. In such a case, it is determined that the photographing apparatus is in a panning state, and normal panning control is performed.

  In FIG. 5, an abnormal drift signal is generated in the output signal of the gyro sensor 9 after the time T3, and the abnormal drift Vn is also generated in the output signal of the aperture position sensor 34 with respect to the target position. At this time, it is determined that the photographing apparatus is placed in an abnormal environment, and shake correction is stopped or limited. Further, if the abnormal drift Vn is a drift amount of about several percent with respect to the aperture target position, there is no influence on photographing. However, when the predetermined drift exceeds a predetermined threshold value of 5%, for example, there is a concern that an abnormal light amount change may occur. Therefore, the position correction process by the aperture position correction unit 43 described above is performed.

  In FIG. 6, the abnormal frequency is superimposed on the outputs of the gyro sensor 9 and the aperture position sensor 34 after the time T4. A frequency-voltage converter (FV converter) is used to detect the abnormal frequency, and a specific abnormal frequency can be easily detected from the converted voltage value. Also in this case, similarly to the description with reference to FIG. 5, it is determined that the photographing apparatus is placed in an abnormal environment, and shake correction is stopped or limited, and the diaphragm position is corrected.

  FIG. 7 is a flowchart of the operation when the abnormal signal is detected.

(Step S11) An angular velocity signal that is an output of the gyro sensor 9 is detected.

(Step S12) It is determined whether or not there is an abnormal drift or an abnormal frequency superposition as shown in FIGS. If there is no abnormal signal, the process returns to the start, and if an abnormal signal is detected, the process proceeds to the next step S13.

(Step S13) The output signal of the aperture position sensor 34 is detected.

(Step S14) Similarly to the detection of the angular velocity signal, it is determined whether or not an abnormal signal is superimposed on the output of the aperture position sensor 34. If there is no abnormal signal, the process returns to the start, and if an abnormal signal is detected, the process proceeds to the next step S15.

(Step S15) The abnormal signal level is determined. For example, in the case of abnormal drift, the level is determined from the drift amount, and in the case of abnormal frequency, the level is determined from the amplitude.

(Step S16) If it is determined in step S15 that the abnormal signal level is high, the light amount change also becomes abnormal. Therefore, the signal of the diaphragm position is corrected, and control is performed so as to obtain an appropriate light amount.

(Step S <b> 17) If a shake correction operation is performed using this abnormal angular velocity signal when an abnormal signal is detected, the shake correction operation is stopped because a malfunction occurs.

(Step S18) When it is determined in step S15 that the abnormal signal level is low, the focal length is detected. At this time, it is determined that the change in the amount of light is sufficiently small, and the aperture position signal need not be corrected.

(Step S19) When the abnormal signal level is small, in order to achieve both the avoidance of the shake correction malfunction and the normal shake correction operation, the shake correction characteristic is changed according to the focal length detected in the previous step S18, and the abnormal signal The shake correction operation is performed within the range where there is no adverse effect due to.

  For example, when the focal length is on the wide-angle side, the image blur is felt sensibly. For this reason, the characteristic of the variable HPF 13 is changed to a gain or cut-off frequency so that shake correction is hardly performed so as to eliminate the influence of the abnormal signal.

  On the other hand, when the focal length is on the telephoto side, the image blur is sensed greatly. For this reason, the gain or cut-off frequency of the variable HPF 13 is lowered within a range that does not adversely affect the abnormal signal so that the shake correction can be used as much as possible.

  As described above, based on the detection signals of the two sensors, the gyro sensor 9 and the aperture position sensor 34, it is possible to detect an abnormality of the device due to electromagnetic waves or the like, and to reduce the abnormal operation of shake correction. . Further, since the abnormal signal is detected by a plurality of sensors, the detection accuracy of the abnormal signal can be improved and no erroneous detection occurs.

  FIG. 8 is a block circuit configuration diagram of the second embodiment. The same reference numerals as those in FIG. 3 denote the same circuit members. The output of the temperature sensor 51 that detects the temperature is connected to the abnormal signal detection unit 41 and the temperature information correction unit 53 via the amplifier 52. The output of the abnormal signal detection unit 41 is connected to the temperature information correction unit 53.

  A temperature signal from a temperature sensor 51, such as a thermistor or a temperature sensitive resistor, is amplified by an amplifier 52. This temperature signal is caused by a focus lens focus shift or a characteristic change of a shake correction drive system that occurs with a change in environmental temperature. Used to correct The temperature sensor 51 must be placed near the unit to be measured, and the signal line distance to the amplifier 52 or after the amplifier 52 is often increased. For this reason, the electromagnetic wave jumps into the signal line, and an abnormal signal similar to that in the case of FIG. 6 is likely to occur. Therefore, the abnormal signal is detected by the gyro sensor 9 and the temperature sensor 51 as in the case of the abnormal signal detection by the gyro sensor 9 and the aperture position sensor 34 of the first embodiment.

  When an abnormal signal is detected, the shake correction characteristic changing unit 42 stops the shake correction operation or restricts the shake correction operation according to the focal length. The focal length information is obtained from the zoom operation unit 44 and the focal length detection unit 45. Further, since the temperature information correction unit 53 erroneously detects the temperature information when the abnormality signal is large, the temperature information correction unit 53 performs the correction even when the abnormality signal is detected.

  FIG. 9 is a flowchart of an abnormal signal detection operation and a control operation using the gyro sensor 9 and the temperature sensor 51.

(Step S21) An angular velocity signal that is an output of the gyro sensor 9 is detected.

(Step S22) It is determined whether or not there is an abnormal frequency superimposed on the angular velocity signal. If there is no abnormal signal, the process returns to the start, and if an abnormal signal is detected, the process proceeds to the next step S23.

(Step S23) The output signal of the temperature sensor 51 is detected.

(Step S24) As in the case of detecting the angular velocity signal, it is determined whether or not there is an abnormal signal superposition. In the case of the temperature sensor 51, it is difficult to distinguish whether the change in the output signal is a drift due to a change in the environmental temperature or a drift due to the occurrence of an abnormal state. Therefore, it is preferable to measure the slope of the temperature change per unit time and determine that an abnormal drift has occurred when the slope is steeper than a predetermined value.

  If there is no abnormal signal, the process returns to the start, and if an abnormal signal is detected, the process proceeds to step S25.

(Step S25) The abnormal signal level is determined. For example, the level is determined from the drift amount in the case of an abnormal drift, and the level is determined from the amplitude in the case of an abnormal frequency.

(Step S26) If it is determined in step S25 that the abnormal signal level is high, the detected temperature is erroneously recognized, so that the temperature information is corrected.

(Step S27) When the shake correction operation is performed using the abnormal angular velocity signal, the shake correction operation is stopped to cause a malfunction.

(Step S28) When it is determined in step S25 that the abnormal signal level is low, the focal length is detected. At this time, it is determined that the abnormal change of the temperature signal due to disturbance noise due to electromagnetic waves or the like is sufficiently small, and the temperature correction may not be performed.

(Step S29) When the abnormal signal level is small, in order to reduce the image blur even slightly, the shake correction characteristic is changed according to the focal length detected in Step S26, and the shake correction operation is performed in a range where there is no adverse effect due to the abnormal signal. I do.

  As described above, similarly to the case where the gyro sensor 9 and the aperture position sensor 34 are used, it is possible to detect an abnormality of the device due to electromagnetic waves or the like based on the detection signals of the two sensors, the gyro sensor 9 and the temperature sensor 51. As a result, it is possible to reduce the abnormal operation of shake correction, and since the abnormal signal is detected by a plurality of sensors, the detection accuracy of the abnormal signal can be improved, and a photographing apparatus with a shake correction function without erroneous detection is obtained. It is done.

  In this embodiment, the shake correction using the variable apex angle prism 1 has been described. However, the shift type shake correction that performs the shake correction by moving the lens in the plane direction perpendicular to the optical axis and displacing the optical path, etc. The present invention can also be applied to a shake correction mechanism.

FIG. 3 is a block circuit configuration diagram of a shake correction function of the imaging apparatus according to the first exemplary embodiment. It is a block circuit block diagram of the aperture control function of the imaging device. It is a block circuit block diagram of the abnormality detection function of the imaging device and the shake correction function at that time. It is a signal waveform of an example of a sensor output. It is a signal waveform of an example of a sensor output. It is a signal waveform of an example of a sensor output. It is an operation | movement flowchart figure. FIG. 6 is a block circuit configuration diagram of an imaging apparatus according to a second embodiment. It is an operation | movement flowchart figure.

Explanation of symbols

1 Variable vertical prism 4 Aperture unit 9 Gyro sensor 12 Panning control unit 13 Variable HPF
Reference Signs List 17 Encoder 23, 38 Actuator 31 Target Aperture Position Setting Unit 34 Aperture Position Sensor 41 Abnormal Signal Detection Unit 42 Shake Correction Characteristic Change Unit 43 Aperture Position Correction Unit 45 Focal Length Detection Unit 51 Temperature Sensor 53 Temperature Information Correction Unit

Claims (10)

In an imaging device with shake correction function,
A shake signal detecting means for detecting a shake signal;
Signal detection means for detecting a signal related to lens control different from the shake signal detection means;
An abnormal signal detecting means for detecting an abnormal signal superimposed on the shake signal detecting means and the signal detecting means;
And a shake correction characteristic changing means for changing the shake correction characteristic,
When an abnormal signal is detected in the output from the shake signal detecting means and the output from the signal detecting means by the abnormal signal detecting means, the shake correction characteristic changing means changes the shake correction characteristic according to the focal length. An imaging apparatus with a shake correction function, characterized in that: 2. The photographing apparatus with a shake correction function according to claim 1 , wherein the signal detection unit that detects a signal related to the lens control is a diaphragm position detection unit that detects a diaphragm position of the diaphragm unit. 3. The photographing apparatus with a shake correction function according to claim 2 , further comprising an aperture position correcting unit that corrects an output from the aperture position detecting unit according to a result of the abnormal signal detecting unit. When an abnormal signal is detected in the output from the shake signal detecting means and the output from the aperture position detecting means, and the drift amount of the abnormal signal exceeds a predetermined value, the aperture position detecting means detects the aperture position. Correcting the output from the means, and stopping the shake correction by the shake correction characteristic changing means,
When the drift amount of the abnormal signal is not more than a predetermined value , the shake correction characteristic is changed according to the focal length by the shake correction characteristic changing unit without correcting the output from the aperture position detecting unit. The photographing apparatus with a shake correction function according to claim 3 . When an abnormal signal exceeding a predetermined frequency is detected in the output from the shake signal detecting unit and the output from the aperture position detecting unit, and the amplitude of the abnormal signal exceeds a predetermined value, the aperture position correcting unit While correcting the output from the aperture position detecting means, and stopping the shake correction by the shake correction characteristic changing means,
When the amplitude of the abnormal signal is less than or equal to the predetermined value, the shake correction characteristic is changed according to the focal length by the shake correction characteristic changing unit without correcting the output from the aperture position detecting unit. The photographing apparatus with a shake correction function according to claim 3 . 2. The photographing apparatus with a shake correction function according to claim 1 , wherein the signal detection unit that detects a signal related to the lens control is a temperature detection unit that detects a temperature. The photographing apparatus with a shake correction function according to claim 6 , further comprising a temperature correction unit that corrects an output from the temperature detection unit according to a result of the abnormal signal detection unit. When an abnormal signal is detected in the output from the shake signal detecting means and the output from the temperature detecting means, and the drift amount of the abnormal signal exceeds a predetermined value, the temperature correcting means While correcting the output, stop the shake correction by the shake correction characteristic changing means,
When the drift amount of the abnormal signal is less than or equal to a predetermined value, the shake correction characteristic is changed according to the focal length by the shake correction characteristic changing unit without correcting the output from the temperature detecting unit. The photographing apparatus with a shake correction function according to claim 7 , wherein: The abnormal signal detecting means measures a slope of temperature change per unit time, and determines that an abnormal signal is detected in the temperature detecting means when the slope is steeper than a predetermined value. The imaging device with a shake correction function according to claim 8 . When an abnormal signal exceeding a predetermined frequency is detected in the output from the shake signal detecting means and the output from the temperature detecting means, and the amplitude of the abnormal signal exceeds a predetermined value, the temperature correcting means While correcting the output from the detection means, stop the shake correction by the shake correction characteristic change means,
When the amplitude of the abnormal signal is equal to or less than the predetermined value, the shake correction characteristic is changed according to the focal length by the shake correction characteristic changing unit without correcting the output from the temperature detecting unit. The photographing apparatus with a shake correction function according to claim 7 , wherein:

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