JP6798192B2 - Signal processing device for accelerometer - Google Patents

Description

The present invention relates to a signal processing device for processing a signal from an acceleration sensor used for camera shake detection.

Many digital cameras have a digitally controlled image stabilization function. The basis of the image stabilization process is to detect fluctuations in the pitch angle (around the X axis) and yaw angle (around the Y axis) of the camera body with an angular velocity sensor, and cancel the image shake based on the signals from both sensors converted into digital signals. The camera shake is corrected by moving the correction lens and image sensor in the direction (2-axis correction). Further, in digital signal processing, in order to detect the output from the sensor with high accuracy, it is necessary to match the output from the sensor with the dynamic range of the AD converter. In the image stabilization device, a configuration is known in which a signal from a Hall element for position detection is amplified according to the dynamic range of an AD converter in order to acquire position information of a moving part required for image stabilization with high accuracy. (See Patent Document 1).

On the other hand, in recent years, in order to perform more precise image stabilization according to various forms of camera shake, in addition to this basic two-axis correction, fluctuations in the roll angle (around the Z axis) are detected by an angular velocity sensor, and X 3-axis correction that corrects rotational fluctuations around all axes, Y-axis, and Z-axis, 4-axis correction that adds translational fluctuation correction in the X-axis direction and Y-axis direction to the basic 2-axis correction, X A 5-axis correction that corrects rotational fluctuations around the axes, Y-axis, and Z-axis and translational fluctuations in the X-axis direction and Y-axis direction has also been proposed. An angular velocity sensor is used to detect rotational fluctuations (rotational runout) of pitch angle, yaw angle, and roll angle, and an acceleration sensor is used to detect translational fluctuations (translational runout) in the X-axis, Y-axis, and Z-axis directions. used.

JP 2015-169928

However, since the acceleration sensor for detecting translational runout also detects gravitational acceleration, the reference voltage changes depending on the posture of the camera. Therefore, in the configuration of simply amplifying the sensor signal as in Patent Document 1, the output from the sensor cannot be adapted to the dynamic range of the AD converter.

More specifically, translational runout often includes slower fluctuations and smaller fluctuations than rotational runout, and for example, detection of a signal having an acceleration of 1 mG or less is desired. However, when the signal from the acceleration sensor is read by a 12-bit AD converter using an acceleration sensor with a sensitivity of ± 2 G, the acceleration of 1 mG is 1 LSB or less of the AD converter and cannot be detected. In order to detect a signal of 1 mG or less, the signal from the sensor may be amplified, but since the acceleration sensor also detects the gravitational acceleration (about 1 G), the gravitational acceleration appears in the signal of the acceleration sensor as an offset. Therefore, 0 (zero) G in the signal of the acceleration sensor does not always correspond to the state where there is no translational deflection, and the fluctuation center of the signal from the sensor fluctuates in the range of about ± 1G depending on the posture of the camera. Therefore, if the amplification factor is set according to the signal having an acceleration of 1 mG or less, the output of the AD converter may be saturated.

The offset of the DC component can be canceled through the high-pass filter, but it is difficult to pass the translational runout through the high-pass filter because it is required to detect a slow fluctuation of several Hz. A solution to increase the resolution of the AD converter is also conceivable, but as the AD converter for camera shake correction, products with a resolution of about 12 bits and a dynamic range of about 0 V to 3 V are often used, and the AD converter for consumers is used. Then, even if the resolution is made higher than this, the actual accuracy is not improved so much, and when the voltage per LSB becomes low, it is buried in the noise of the output signal of the sensor, and the increased resolution can hardly be used effectively. Can be considered. In order to solve these problems, it is necessary not only to increase the resolution of the AD converter but also to expand the dynamic range, and the high power supply voltage required for it is required. The effect that can be expected is low for the cost of increasing the area of parts and boards.

An object of the present invention is to detect a signal of an acceleration sensor with high accuracy.

The signal processing device of the present invention comprises a first amplification means for amplifying or offset adjusting a sensor signal from an acceleration sensor, a second amplification means for amplifying a sensor signal or a signal from the first amplification means, and a first amplification means. The reference voltage setting means for setting the reference voltage of the second amplification means based on the output of the sensor signal is provided, and the amplification factor of the output of the second amplification means with respect to the sensor signal is higher than the amplification factor of the output of the first amplification means with respect to the sensor signal. It is characterized by being expensive.

The reference voltage is set when the output from the first amplification means satisfies a predetermined condition. The signal processing device includes AD conversion means, and the outputs of the first amplification means and the second amplification means are converted into digital values by the AD conversion means. The AD conversion means may include a first AD converter that AD-converts the output of the first amplification means and a second AD converter that AD-converts the output of the second amplification means. Further, the AD conversion means includes a switching means for switching an input between an output from the first amplification means and an output from the second amplification means, and converts one of the outputs from the first or second amplification means into a digital value. It may be configured to be used.

The reference voltage is set based on, for example, the digital value of the output of the first amplification means. The signal processing device includes DA conversion means, and the reference voltage of the second amplification means is output to the second amplification means via the DA conversion means.

A voltage holding means for holding the output voltage of the first amplification means may be provided, and the reference voltage setting means may set the reference voltage to the voltage held by the voltage holding means. The amplifier may be shared by the second amplification means and the voltage holding means. The first amplification means may transmit the signal of the acceleration sensor at the same magnification.

The camera shake correction device of the present invention is an image pickup device including the above signal processing device, and is characterized in that translational shake correction is performed based on the output of the second amplification means.

Further, the imaging device of the present invention is an imaging device including the camera shake correction device, and the reference voltage setting means does not change the setting of the reference voltage during the exposure period.

According to the present invention, the signal of the acceleration sensor can be detected with high accuracy.

It is a block diagram which shows the structure of the digital camera which mounted the camera shake correction apparatus of one Embodiment of this invention. It is a circuit diagram which shows the structure of the circuit part of 1st Embodiment. It is a graph which shows the timing of setting of a reference voltage. It is a circuit diagram which shows the structure of the circuit part of 2nd Embodiment. It is a circuit diagram which shows the structure of the circuit part of 3rd Embodiment. It is a circuit diagram which shows the structure of the circuit part of 4th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block showing an electrical configuration related to a camera shake correction mechanism of a digital camera (imaging device) equipped with the camera shake correction device according to the first embodiment of the present invention.

The digital camera 10 includes an angular velocity sensor 12 and an acceleration sensor 14 for detecting camera shake. The angular velocity sensor 12 and the acceleration sensor 14 refer to a plurality of axes including at least the X axis and the Y axis among the three orthogonal axes X (pitch axis), Y axis (yaw axis), and Z axis (roll axis) of the camera body. Detects rotational runout and translational runout.

The outputs from the angular velocity sensor 12 and the acceleration sensor 14 are input to the amplifier / filter circuits 16 and 18 of the present embodiment, respectively, and after being subjected to predetermined signal processing, are input to the AD / DA converter (ADC) 20. It is converted into a digital signal (note that the amplifier and filter may be built in the package of the angular velocity sensor 12 and the acceleration sensor 14). The sensor signals of the angular velocity sensor 12 and the acceleration sensor 14 converted into digital signals are input to the camera shake correction calculation unit 22 each composed of a DSP or the like, and a correction calculation for canceling the camera shake is performed.

In the present embodiment, the camera shake correction device translates the lens frame of a correction lens (not shown) configured as a movable portion or the stage of the image sensor in the X-axis direction and the Y-axis direction, and further moves the stage of the image sensor to the Z-axis. By rotating it around, the rotational runout and translational runout that occur around the X-axis, Y-axis, and Z-axis are offset. As is well known in the past, the camera shake correction calculation unit 22 is in each axial direction based on the sensor signals (shake signals) from the angular velocity sensor 12 and the acceleration sensor 14, the focal distance, and the current position information of the movable part (described later). The translational movement amount of the movable part and the rotation amount of the movable part around the Z axis are calculated, and a drive signal is output to the actuator driver 24 of the camera shake correction device.

The actuator driver 24 drives the actuator 26 for moving the movable portion based on the drive signal. The image stabilization device includes a plurality of position detection sensors 28 that detect the position of the movable part, and a signal corresponding to the position of the movable part moved by the actuator 26 for moving the movable part is transmitted from the position detection sensor 28 to an amplifier / filter circuit. It is input to 30. The position detection sensors 28 are provided in as many positions as necessary for the control according to the translational motion and the rotational motion of the movable portion to be controlled.

Amplified by the amplifier / filter circuit 30; the sensor signal from the filtered position detection sensor 28 is input to the AD / DA converter 20 to be converted into a digital signal, and then input to the camera shake correction calculation unit 22 for detection. The current position information of the movable part is used to calculate the next translational movement amount of the movable part in each axial direction and the next rotation amount of the movable part around the Z axis. This series of operations is repeated at regular intervals during the image stabilization operation. In the present embodiment, the same AD / DA converter 20 is used for AD conversion of the sensor signals from the angular velocity sensor 12, the acceleration sensor 14, and the position detection sensor 28, and they are switched by a switch or the like, but they are different from each other. An AD converter may be prepared. Further, the camera shake correction calculation unit 22 is controlled by, for example, the camera main calculation unit 32 that controls the entire digital camera 10. A main memory 34 is connected to the camera main calculation unit 32.

Next, the sensor signal amplification process according to the first embodiment will be described with reference to FIG. FIG. 2 is a circuit diagram showing the circuit configurations of the amplifier / filter circuits 16 and 18 related to the amplification of the sensor signal from the acceleration sensor 12 (the circuit unit corresponding to the filter is omitted).

FIG. 2 shows a circuit configuration until an output from one uniaxial acceleration sensor arbitrarily selected from a plurality of acceleration sensors 14 is input to a camera shake correction calculation unit. A plurality of similar circuit configurations can be provided for each axis for the multi-axis acceleration sensor. However, although the configuration of the amplifier circuit for the X-axis and Y-axis acceleration sensors may generally be the same, it may be desirable to have a different configuration for the Z-axis because the usage method and correction method are often different.

Since the detection sensitivity of the acceleration sensor 14 should be sensitive, the detection range is, for example, about ± 2G. Therefore, the influence of the gravitational acceleration (about 1 G) on the signal component of the acceleration sensor 14 is relatively large, and there is a possibility that the dynamic range of AD conversion may not be contained depending on the posture of the camera. From these facts, in this embodiment, the amplification factor of the sensor signal can be changed according to the posture of the camera body so that the sensor signal always falls within the dynamic range of AD conversion even if the highly sensitive acceleration sensor 14 is used. ing.

The signal from the acceleration sensor 14 is amplified or offset adjusted by the first amplifier AMP1 of the amplifier circuit unit 18A of the amplifier / filter circuit 18, and the output thereof is the first AD converter ADC1 of the AD / DA converter 20 and the amplifier / filter circuit 18. It is input to the second amplifier AMP2 of the amplifier circuit unit 18A. The first amplification factor, which is the amplification factor of the first amplifier AMP1, is a low amplification factor or an equal magnification.

A predetermined first reference voltage Vref1 corresponding to zero runout is input to the first amplifier AMP1 via a pull-down resistor, and the differential input of the sensor signal based on this is amplified by the first amplification factor and output. Output from the terminal. If the first amplifier AMP1 has the same magnification and offset adjustment is not required, the terminal of the acceleration sensor 14 may be directly connected to the input terminal of the first AD converter ADC1 or the second amplifier AMP2, or the first amplifier AMP1 May be configured as a voltage follower.

The second reference voltage Vref2, which will be described later, is input to the second amplifier AMP2 via a pull-down resistor, and the differential input of the signal input from the first amplifier AMP1 with this as a reference is the second amplification factor (more than 1 times). Amplified by a large value). The signal output from the second amplifier AMP2 is input to the second AD converter ADC2 of the AD / DA converter 20, converted into a digital signal, and then input to the camera shake correction calculation unit 22.

The second reference voltage Vref2 with respect to the second amplifier AMP2 is changed based on the instruction from the camera shake correction calculation unit 22, and is supplied to the second amplifier AMP2 through the DA converter DAC of the AD / DA converter 20. That is, when the translational blur correction is set to ON in the camera and the camera is in a state where shooting is possible, the digital value of the sensor signal input via the first AD converter ADC1 is constantly monitored by the camera shake correction calculation unit 22. When "the average value of the sampling values for the predetermined number of times in the first AD converter ADC1 is within the fluctuation range within the predetermined range over the predetermined time or continuously for the predetermined number of times", the voltage or the average value at that time is periodically used. Is set to the second reference voltage Vref2. If the value of the first AD converter ADC1 or the second AD converter ADC2 fluctuates beyond a predetermined value while the output of the first AD converter ADC1 is being monitored, the set value of the second reference voltage Vref2 is temporarily changed. When the operation is stopped and the above condition, that is, the condition that "the average value of the sampling values for a predetermined number of times in the first AD converter ADC1 is within the fluctuation within the predetermined range for a predetermined time or continuously for a predetermined number of times" is satisfied, the third is performed again. 2 The set value of the reference voltage Vref2 is updated.

When the user is moving with the camera or trying various angles, the acceleration changes greatly, and the signal output from the acceleration sensor 14 also changes greatly. On the other hand, when the angle is determined, the camera is held in a constant posture, and the state is maintained, the signal output from the acceleration sensor 14 is relatively stable, and the fluctuation is limited to a minute fluctuation of about translational deflection. Therefore, the above condition, "the average value of the sampling values for a predetermined number of times in the first AD converter ADC1 is within a predetermined range for a predetermined time or continuously for a predetermined number of times", that is, the output from the first amplifier AMP1 The situation where is stable corresponds to, for example, a state where the angle is determined and the camera posture is stable. At this time, the output from the first amplifier AMP1 or its average value includes the influence of the gravitational acceleration due to the camera posture. It roughly corresponds to the center value of the fluctuation of the camera shake signal. Therefore, assuming that the output value or the average value at this time is the second reference voltage Vref2 of the second amplifier AMP2, the signal amplification in the second amplifier AMP2 is the amplification only for the translational deflection component from which the offset value due to the gravitational acceleration is removed. The detection sensitivity of the acceleration sensor 14 can be fully utilized.

When the release operation is performed, the camera shake correction calculation unit 22 calculates the amount of movement of the movable part corresponding to the translational shake based on the sensor signal from the second AD converter ADC2, outputs the drive signal to the actuator driver 24, and translates. Perform runout correction. However, when the sampling value of the second AD converter ADC2 exceeds the dynamic range, the data value acquired through the second AD converter ADC2 is saturated and the correct acceleration cannot be obtained. Therefore, the camera shake correction calculation unit 22 again performs the above. Translational blur correction using the value of the second AD converter ADC2 is prohibited until the conditions in the first AD converter ADC1 are satisfied. During this period, the correction process may be performed using the first AD converter ADC1, and in that case, a certain limit may be applied to the correction control such as a limit on the correction width.

Next, referring to the graph of FIG. 3, the timing of reading the signals from the first AD converter ADC1 and the second AD converter ADC2 in the image stabilization calculation unit 22 and the change of the second reference voltage Vref2, and the acceleration sensor 14 The relationship between the detected acceleration and the digital output in the first and second AD converters ADC1 and ADC2 will be described.

The horizontal axis of FIG. 3 is time, and the left vertical axis is the acceleration [G] detected by the acceleration sensor 14. The right vertical axis shows the output from the first amplifier AMP1 corresponding to the acceleration, the 12-bit digital output value (0 to 4095) of the first AD converter ADC1 using this as an input, and the second amplifier AMP2 corresponding to the acceleration. The output and the 12-bit digital output value (0 to 4095) of the second AD converter ADC2 using the output are shown. Further, in the lower part of FIG. 3, the timing of reading from the first AD converter ADC1 and the second AD converter ADC2 by the image stabilization calculation unit 22 is shown.

The initial period T1 corresponds to a state in which the user is moving with the camera and a state in which various angles are being tried, and in the period T1, the acceleration detected by the acceleration sensor 14 changes significantly. When the angle is determined and the camera is held, the output of the accelerometer 14 is relatively stable, and the change is limited to a minute change of about translational runout. When the camera shake correction calculation unit 22 confirms the stability of the acceleration in the period T2 (for example, corresponding to the determination that the camera is held), the second reference voltage Vref2 described above is updated at the time t0, and in the subsequent period T3, Continue the same process. That is, when the camera is set to the translational blur correction ON and is in the shooting mode, the camera shake correction calculation unit 22 constantly monitors the output of the first AD converter ADC1 and the average value for a certain number of samples is constant. If it falls within a certain change over time, the voltage value or average value at that time is output from the DA converter DAC, and the amplification reference voltage Vref2 of the second amplifier AMP2 is updated.

Next, when the release switch is turned on at time t1, the exposure period T5 is started after the release time lag T4, and the output value from the second AD converter ADC2 is used for translational runout correction during exposure. However, in some single-lens reflex cameras, the output of the acceleration sensor 14 fluctuates greatly due to a mirror shock or a shutter shock during the initial period T6 of the exposure period T5. In such a camera, the vibration period T6 peculiar to the camera is measured and stored in advance, and the output value from the first AD converter ADC1 is continuously referred to during the vibration period T6 even during exposure. That is, since the output of the acceleration sensor 14 fluctuates greatly during the vibration period T6, there is a high possibility that the output from the second amplifier AMP2 exceeds the dynamic range of the second AD converter ADC2, and therefore the value of the first AD converter ADC1 during that period. Perform the correction operation with reference to.

When the vibration period T6 ends, the camera shake correction calculation unit 22 starts referencing the output from the second AD converter ADC2, and corrects the translational runout generated in the exposure period T5 based on the digital output value from the second AD converter ADC2. Is executed in the period T7 until the end of the exposure period T5. It is prohibited to change the setting of the second reference voltage Vref2 using the DA converter DAC during the exposure period T5.

When the exposure period T5 ends, the translational shake correction also ends, and the camera shake correction calculation unit 22 refers to the output value from the first AD converter ADC1 again. Note that the image stabilization calculation unit 22 continues reading even in the broken line portion of the straight line indicating the reading timing of the first and second AD converters ADC1 and ADC2 in FIG. 3, and the output values from both the first and second AD converters ADC1 and ADC2. May be read.

In FIG. 3, the first amplification factor of the first amplifier AMP1 is such that the range of acceleration ± 2.0 [G], which is the detection range of the acceleration sensor 14, corresponds to the digital output 0 to 4095 of the first AD converter ADC1. The second amplification factor of the second amplifier AMP2 is such that the output range from the second amplifier AMP2 is sufficiently expanded with slight fluctuations in translational fluctuation centered on the second reference voltage Vref2, and the second AD converter ADC2 is set to. It is set to correspond to the digital output 0 to 4095 of. In FIG. 3, about 0.6 [G] to 1.0 [G] are set to correspond to the digital outputs 0 to 4095 of the second AD converter ADC2.

As described above, according to the first embodiment, the offset amount due to the gravitational acceleration is detected, and the offset amount is removed from the output of the acceleration sensor and amplified to obtain a digital signal with high resolution for minute fluctuations in translational runout. Can be obtained. As a result, the reference voltage of the amplifier circuit can be appropriately set regardless of the posture of the camera, and the translational runout can be corrected with high accuracy.

In the first embodiment, the output signal of the first amplifier AMP1 is used as the input signal to the second amplifier AMP2, but the output signal of the acceleration sensor 14 may be directly input to the second amplifier AMP2. .. When the output of the first amplifier AMP1 is input to the second amplifier AMP2 as in the first embodiment, the second amplification factor of the second amplifier AMP2 may be set to an amplification factor larger than 1 times, but the acceleration sensor 14 When the output signal of is directly input to the second amplifier AMP2, the second amplification factor of the second amplifier AMP2 is set higher than the first amplification factor of the first amplifier AMP1.

In the first embodiment, the second amplifier AMP2 is not used, and a switch is provided on a resistor or the like that determines the amplification factor of the first amplifier AMP1 so that the first amplifier AMP1 can select a plurality of amplification factors. You may set the amplification factor with, but there is a problem that the response is slow.

Next, signal processing for translational runout correction in the second embodiment will be described with reference to FIG.

FIG. 4 corresponds to FIG. 2 of the first embodiment. In the first embodiment, two first and second AD converters ADC1 and ADC2 are used, but in the second embodiment, only one AD converter ADC is used, and instead, an analog switch is provided in front of the AD converter ADC. Provide. That is, one AD converter ADC can read the outputs of the first amplifier AMP1 and the second amplifier AMP2. The other configurations are the same as those in the first embodiment, and the same reference numerals are used for the same configurations, and the description thereof will be omitted.

The signals amplified by the first amplifier AMP1 and the second amplifier AMP2 of the amplifier circuit unit 18A of the amplifier / filter circuit 18 are analog switches of the AD / DA converter (ADC) 40 corresponding to the AD / DA converter (ADC) 20. It is input to SW) 42. The analog switch 42 selectively outputs one of the two inputs to the AD converter ADC1. The signal converted into a digital signal by the AD converter ADC1 is input to the camera shake correction calculation unit 22, and is processed in the same manner as in the first embodiment. The switching of the analog switch 42 is controlled by the camera shake correction calculation unit 22.

As described above, in the configuration of the second embodiment, substantially the same effect as that of the first embodiment can be obtained. In the second embodiment, it is not possible to control while reading the outputs of the first amplifier AMP1 and the second amplifier AMP2 at the same time, but a broken straight line indicating the reading timing of the first and second AD converters ADC1 and ADC2 in FIG. It is not necessary for the unit to read, and the camera shake correction calculation unit 22 switches the selection of the analog switch 42 at the same timing.

Next, the signal processing for translational runout correction in the third embodiment will be described with reference to FIG.

The configuration of the amplifier circuit unit 18A and the configuration of the AD / DA converter (ADC) 40 of the third embodiment are the same as those of the second embodiment. However, in the third embodiment, the setting unit of the second reference voltage Vref2 input to the second amplifier AMP2 is different from that of the second embodiment. That is, in the second embodiment, the second reference voltage Vref2 is set by using the DA converter DAC, but in the third embodiment, it is configured by the analog voltage holding circuit (HOLD) 44 via the low-pass filter 43. There is. This configuration is useful, for example, in systems that lack DA converters. The same reference numerals are used for the same configurations as those of the first and second embodiments, and the description thereof will be omitted.

The analog voltage holding circuit 44 includes two switches 46 and 48, and the output from the first amplifier AMP1 is input to the second amplifier AMP2 and input to the analog voltage holding circuit 44 via the low-pass filter (LPF) 43. Will be done. The input from the low-pass filter 43 is input to the operational amplifier 50 used as a voltage follower via the switch 46, and the voltage thereof can be recorded in the capacitor 52. That is, when the switch 46 is turned on with the switch 48 connected in parallel with the capacitor 52 turned off, the capacitor 52 is charged and the voltage is maintained when the switch 46 is turned off. When the switch 48 is turned on, the capacitor 52 is discharged and the held voltage is reset.

The camera shake correction calculation unit 22 monitors the output from the first amplifier AMP1, and when the conditions for setting the second reference voltage Vref2 described in the first embodiment are satisfied, the switch 48 is turned off and the switch 46 is turned off. Is turned on for a predetermined time, and the output voltage from the first amplifier AMP1 at that time is held in the capacitor 52. The voltage held in the capacitor 52 is output from the operational amplifier 50 and input to the second amplifier AMP2 as the second reference voltage Vref2.

The low-pass filter 43 cancels noise and small translational fluctuation components contained in the output of the first amplifier AMP1 and then inputs them to the analog voltage holding circuit 44. A reference voltage that is not affected by noise or small translational fluctuation is applied. Provided to obtain. It is desirable that the operational amplifier 50 and the capacitor 52 are composed of components having a small leakage current, and the smaller the capacitance of the capacitor 50, the shorter the charge time and the faster the response.

As described above, in the configuration of the third embodiment, substantially the same effect as that of the first and second embodiments can be obtained, and one DA converter can be omitted. Instead of the AD / DA converter (ADC) 40, the AD / DA converter (ADC) 20 of the first embodiment can also be used.

Next, the signal processing for translational runout correction in the fourth embodiment will be described with reference to FIG.

The basic configuration of the fourth embodiment is the same as that of the third embodiment, but the operational amplifier 50 used as the voltage follower in the analog voltage holding circuit 44 of the third embodiment is replaced by the second amplifier AMP2. .. The same reference numerals are used for the same configurations as those in the first to third embodiments, and the description thereof will be omitted.

An operational amplifier such as C-MOS or Bi-MOS having a high input impedance is used as the second amplifier AMP2 of the amplifier circuit unit 54 of the amplifier / filter circuit 18. Although the output polarity of the second amplifier AMP2 is inverted from that of the third embodiment, the polarity can be inverted by the camera shake correction calculation unit 22, so that the same processing as that of the third embodiment can be realized.

As described above, the same effect as that of the third embodiment can be obtained in the fourth embodiment, and the use of the operational amplifier can be reduced by one by keeping the input impedance on the analog voltage circuit 56 side high. Also in the fourth embodiment, the AD / DA converter (ADC) 20 of the first embodiment can be used instead of the AD / DA converter (ADC) 40.

The present embodiment can also be applied to a single-lens reflex digital camera, a mirrorless digital camera, a compact camera, or other electronic devices having a camera function. The movable portion may be provided with a lock mechanism.

10 Digital camera 14 Accelerometer 18A Amplifier circuit section 20 AD / DA converter (ADC)
22 Shake correction calculation unit 24 Actuator driver 26 Actuator for moving moving parts ADC1 1st AD converter ADC2 2nd AD converter AMP1 1st amplifier AMP2 2nd amplifier DAC DA converter Vref1 1st reference voltage Vref2 2nd reference voltage

Claims (14)

A first amplification means that amplifies or offsets the sensor signal from the accelerometer,
A second amplification means that amplifies the sensor signal or the signal from the first amplification means, and
A reference voltage setting means for setting a reference voltage of the second amplification means based on the output from the first amplification means is provided.
The signals output from the first amplification means and the second amplification means are output as camera shake correction signals.
The amplification factor of the output of said second amplifying means for the sensor signals, rather higher than the amplification factor of the output of said first amplifying means with respect to said sensor signal,
A signal processing device characterized in that one output of the first and second amplification means is selectively used for image stabilization . The signal processing apparatus according to claim 1, wherein the reference voltage is set when the output from the first amplification means satisfies a predetermined condition. Claims 1 and 2, wherein the signal processing device includes AD conversion means, and the outputs of the first amplification means and the second amplification means are converted into digital values by the AD conversion means.
The signal processing device according to any one of the above. 3. The third aspect of the present invention is that the AD conversion means includes a first AD converter that AD-converts the output of the first amplification means and a second AD converter that AD-converts the output of the second amplification means.
The signal processing device according to. The AD conversion means includes a switching means for switching an input between an output from the first amplification means and an output from the second amplification means, and one of the outputs from the first or second amplification means is digital. The signal processing apparatus according to claim 3, wherein the signal processing apparatus is converted into a value. The signal processing apparatus according to any one of claims 3 to 5, wherein the reference voltage is set based on a digital value of the output of the first amplification means. The signal processing device according to claim 6, wherein the signal processing device includes DA conversion means, and a reference voltage of the second amplification means is output to the second amplification means via the DA conversion means. .. The first to fifth aspects of claim 1 to 5, further comprising a voltage holding means for holding the output voltage of the first amplification means, wherein the reference voltage setting means sets the reference voltage to a voltage held by the voltage holding means. The signal processing device according to any one item. The signal processing device according to claim 8, wherein an amplifier is shared between the second amplification means and the voltage holding means. The signal processing device according to any one of claims 1 to 9, wherein the first amplification means transmits a signal of an acceleration sensor at the same magnification. The invention according to any one of claims 1 to 10, wherein the output from the second amplification means is output as a camera shake correction signal in a state where the output from the first amplification means is stable. Signal processing device. A camera shake correction device including the signal processing device according to claims 1 to 11, wherein the camera shake correction is performed based on the output of one of the first and second amplification means. A camera shake correction device including the signal processing device according to claims 1 to 11, wherein the translational shake correction is performed based on the output of the second amplification means. An imaging device including the camera shake correction device according to claim 13, wherein the reference voltage setting means does not change the setting of the reference voltage during the exposure period.

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