JP4924321B2 - Imaging apparatus, camera shake detection element calibration execution method, and program - Google Patents

Description

  The present invention relates to an imaging apparatus or the like provided with a correction mechanism that detects shake of a captured image due to camera shake or the like by a camera shake detection element and corrects the shake of the captured image.

  In recent years, with the increase in the resolution of solid-state imaging devices such as CCD (Charge-Coupled Devices) and CMOS (Complementary Metal-Oxide Semiconductor) sensors, the demand for various information devices having imaging functions is rapidly increasing. In response to this situation, the size and weight of these information devices are being reduced. However, these small and lightweight information devices have an advantage that they are convenient to carry, but there is a problem that camera shake is likely to occur depending on the holding state of the camera at the time of shooting.

  Therefore, in order to mechanically prevent camera shake of the photographed image, for example, a camera shake detection element such as a gyro sensor is provided, and the direction and the amount of camera shake are detected from the output voltage from the gyro sensor. There was a way to shift the sensor.

  However, the gyro sensor needs to be calibrated, but in the conventional camera shake correction mechanism, whether the output voltage value from the gyro sensor is an output due to the “camera shake” operation or whether the imaging device is placed, Or, it was difficult to determine whether it was due to a noise signal. Therefore, when the calibration of the gyro sensor is executed, it is performed in an environment that is shielded from vibration and noise in a factory, a repair work place, or the like.

In order to avoid such a problem, a technique for performing calibration of a shake detection element such as a gyro sensor in a state in which the imaging apparatus is attached to a tripod and with little shake is known (for example, , See Patent Document 1).
JP 2003-189164 A

  However, in the conventional image stabilization mechanism as described above, since the calibration of the gyro sensor is performed at the time of factory shipment of the imaging device or at the time of repair due to a failure, the reference voltage value of the gyro sensor is changed due to aging deterioration, environmental change, etc. Even if it changes, there is a problem that the calibration cannot be executed again and the accuracy of camera shake correction deteriorates. Further, in the technique described in Patent Document 1, since it is an essential requirement to use a tripod, if the tripod is not used, the calibration cannot be performed as described above, There has been a problem that the accuracy of camera shake correction deteriorates.

  Therefore, the present invention has been made in view of the above-described problem, and an imaging apparatus capable of executing calibration of a shake detection element such as a gyro sensor at an appropriate timing, and a calibration execution method of the shake detection element And to provide a program.

  The present invention proposes the following matters in order to solve the above problems.

  (1) The present invention relates to a detection unit that detects a charge state, a calibration execution unit that performs calibration of a camera shake detection element, and a calibration in the calibration execution unit when the detection unit detects the start of charging. And an image pickup apparatus characterized by comprising control means for controlling the start of an image.

  (2) According to the present invention, with respect to the imaging device of (1), a predetermined number of output values of the camera shake detection element are obtained, and a calculation means for calculating an average value of the output values, an average value of the calculated output values and a reference A difference determining means for determining whether or not a difference from the voltage value is equal to or less than a predetermined value; and if the difference between the average value of the calculated output value and the reference voltage value is equal to or less than a predetermined value, the reference voltage value is averaged An image pickup apparatus characterized by further comprising update means for updating with a value is proposed.

  (3) According to the present invention, in the imaging device of (1) or (2), when the control unit detects that the detection unit starts or stops charging, the calibration execution unit performs calibration. There has been proposed an imaging apparatus characterized by transmitting a start signal or a calibration end signal to control the calibration execution means.

  (4) According to the present invention, in the imaging device of (1) or (2), when the control unit detects that the detection unit has started charging or stopped charging, the calibration execution unit performs calibration. There has been proposed an imaging apparatus characterized by transmitting a start signal or a calibration end signal to control the calibration execution means.

  (5) The present invention is a method for performing calibration of a camera shake detection element in an imaging apparatus, the first step of detecting a charging state of the imaging apparatus main body, and a camera shake correction module when detecting the start of charging. A second step of activating the first step, a third step of obtaining a predetermined number of output values of the shake detecting element and calculating an average value of the output values, and an average value of the calculated output values and a reference voltage value A fourth step of determining whether or not the difference is less than or equal to a predetermined value; and if the difference between the calculated average value of the output value and the reference voltage value is less than or equal to a predetermined value, the reference voltage value is A fifth step of updating and returning the processing to the first step when the difference between the average value of the calculated output value and the reference voltage value is greater than a predetermined value. Calibration of detector element It has proposed a line method.

  (6) The present invention is a program for causing a computer in an imaging apparatus to execute calibration of a camera shake detection element in the imaging apparatus, the first step of detecting a charging state of the imaging apparatus body, and the charging A second step of activating the camera shake correction module when the start is detected, a third step of obtaining a predetermined number of output values of the camera shake detection element and calculating an average value of the output values, and the calculated output A fourth step of determining whether or not the difference between the average value of the values and the reference voltage value is less than or equal to a predetermined value, and the difference between the calculated average value of the output values and the reference voltage value is less than or equal to a predetermined value A reference voltage value is updated with an average value, and if the difference between the calculated average value of the output value and the reference voltage value is greater than a predetermined value, the fifth step returns the processing to the first step. And the computer It has proposed a program to be executed by the.

  According to the present invention, it is possible to always maintain the accuracy of camera shake correction at an appropriate timing by performing calibration while the photographing apparatus is being charged. In addition, since the user is not allowed to perform maintenance when the accuracy of camera shake correction is reduced, there is an effect that the burden on the user is greatly reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that the constituent elements in the present embodiment can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the description of the present embodiment does not limit the contents of the invention described in the claims.

<First Embodiment>
The first embodiment will be described with reference to FIGS. 1 to 3.

<Electrical configuration of imaging device>
As shown in FIG. 1, the imaging apparatus 100 according to the present embodiment includes a key input unit 10, a strobe light emitting unit 20, an LCD 21, a lens 30, a lens driving block 31, an aperture / shutter 32, and a CCD 40. , Image processing unit 41, charging state detection unit 42, external communication I / F (Interface) 43, strobe drive unit 44, recording medium 45, recording medium I / F (Interface) 46, memory 47, , A DRAM (Dynamic Random Access Memory) 48, a camera shake correction unit 50, and a CPU (Central Processing Unit) 60. The recording medium I / F 46 has a memory in a card slot of the imaging apparatus 100 main body (not shown). A recording medium 45 such as a card is detachably connected. That.

  The key input unit 10 includes a plurality of operation keys such as a mode dial, a power button, a shutter button, a Play button, a Rec button, a moving image button, a SET key, a control button, a MENU button, a DISP key, and the like according to a user's key operation. The operation signal is output to the CPU 60.

  The lens 30 includes a focus lens and a zoom lens, and a lens driving block 31 is connected thereto. The lens drive block 31 drives a focus motor and a zoom motor that drive a focus lens and a zoom lens (not shown) in an optical axis direction parallel to the imaging surface, respectively, and a focus motor and a zoom motor according to a control signal from the CPU 60, respectively. It consists of a focus driver and a zoom motor driver.

  The aperture / shutter 32 includes a drive circuit (not shown), and this drive circuit operates the aperture / shutter according to a control signal sent from the CPU 60. The aperture / shutter 32 functions as an aperture and a shutter.

  Here, the aperture refers to a mechanism that controls the amount of light that enters from the imaging lens 30, and the shutter refers to a mechanism that controls the time during which light is applied to the CCD 40. In addition, since the time during which light is applied to the CCD 40 (exposure time) varies depending on the shutter opening / closing speed (shutter speed), the amount of exposure can be determined by the aperture and the shutter speed.

  The CCD 40 converts the light of the subject projected through the imaging lens 30 and the aperture / shutter 32 into an electrical signal, and outputs the electrical signal to the image processing unit 41.

  The image processing unit 41 is a CDS (Correlated Double Sampling) circuit that holds the imaging signal output from the CCD 40 by correlated double sampling, an AGC (Automatic Gain Control) circuit that performs automatic gain adjustment of the imaging signal after the sampling, The analog gain signal after the automatic gain adjustment is composed of an A / D converter that converts it into a digital signal. Further, image processing (pixel interpolation processing, γ correction, generation of luminance / color difference signals, white balance processing, exposure correction processing, etc.) of the digital signal is executed.

  The CPU 60 is a one-chip microcomputer that controls each unit of the imaging apparatus 100 according to a control program, and includes a clock circuit that measures time.

  The DRAM 48 temporarily stores various data such as display data. It is also used as a working memory for the CPU 60.

  The external communication I / F 43 performs data input / output with an external electronic device (for example, a personal computer), and enables input / output according to various interface standards such as the USB standard and the IEEE 1394 standard. It can be connected to electronic devices such as personal computers that can input and output data according to the above standards. In addition, image data may be input / output to / from an external electronic device by infrared communication based on the IrDA standard or wireless communication based on the Bluetooth standard.

  The strobe driving unit 44 drives the strobe light emitting unit 20 to flash in accordance with a control signal from the CPU 60, and the strobe light emitting unit 20 thereby causes the strobe to flash. The CPU 60 determines whether or not the shooting scene is dark by a photometric circuit (not shown), and determines that the shooting scene is dark and when shooting is performed (when the shutter button 4 is pressed), the flash drive unit 44 Output a control signal.

  The memory 47 records and stores a program necessary for controlling each part of the imaging apparatus 100 by the CPU 60 and data necessary for controlling each part, and the CPU 60 executes processing according to this program.

  The charging state detection unit 42 detects the charging current from the charging stand, detects the start and end of charging (including the case where the imaging device 100 is disconnected from the charging stand during charging), and according to the state. The received signal is transmitted to the CPU 60.

  The camera shake correction unit 50 is activated by the CPU 60 during the imaging operation of the imaging apparatus 100 and performs camera shake correction processing. In addition, the camera shake correction unit 50 is activated by the CPU 60 when charging of the imaging device 100 is started, and performs a calibration process. At this time, in the calibration process, a predetermined number of output values of the camera shake detection element in the camera shake correction unit 50 are obtained, an average value of the output values is calculated, and a difference between the calculated average value of the output values and the reference voltage value If the difference between the calculated average value of the output value and the reference voltage value is equal to or less than the predetermined value, the reference voltage value is updated with the average value and calculated. If the difference between the average value of the output values and the reference voltage value is larger than the predetermined value, the process of returning to the first step is executed. Details of the configuration and processing will be described later.

<Configuration of image stabilization unit>
As shown in FIG. 2, the camera shake correction unit according to this embodiment includes a CCD 40, an actuator 51, a camera shake correction control unit 52, a movement amount detection unit 53, a work memory 54, and a flash ROM 55. ing. The CCD 40 is connected to the image processing unit 41, and the image processing unit 41 is connected to the DRAM 48 and the CPU 60. Further, the camera shake correction control unit 52 is connected to the CPU 60, and the CPU 60 is connected to the charging state detection unit 42. In addition, since it has the same function about the component which attaches | subjects the same code | symbol as FIG. 1, the detailed description is abbreviate | omitted.

  The actuator 51 moves the CCD 40 mounted on the correction stage from front to back and right and left based on a control signal from the camera shake correction control unit 52, and converts the input control signal into a physical quantity.

  The movement amount detection unit 53 includes a camera shake detection element such as a gyro sensor, detects the movement amount of the image sensor 100, that is, the camera shake amount, converts this to a voltage, and outputs the voltage.

  Based on the control start command or control end command from the CPU, the camera shake correction control unit 52 reads the camera shake correction control program stored in the flash ROM 55 and executes or stops the camera shake correction process. The camera shake correction control unit 52 compares the voltage output from the movement amount detection unit 53 with a reference voltage, and outputs a control signal to the actuator 51 so as to cancel the camera shake based on the voltage. Based on the control signal from the camera shake correction control unit 52, the actuator 51 corrects the camera shake by moving the correction stage on which the CCD 40 is arranged back and forth and right and left.

  Further, the camera shake correction control unit 52 reads the calibration program stored in the flash ROM 55, and executes or stops the calibration process of the camera shake correction unit. In a stationary state, the camera shake correction control unit 52 acquires the output voltage of a camera shake detection element such as a gyro sensor included in the movement amount detection unit 53, and sets this as a new reference voltage, thereby allowing the movement amount detection unit 53 to Calibration of a shake detection element such as a gyro sensor included is performed. The work memory 54 is a memory that temporarily stores data such as an output voltage value detected from the movement amount detection unit 53. The flash ROM 55 stores a correction control program, a calibration program, reference voltage information, and the like.

<Calibration process of camera shake correction unit>
Next, the calibration process of the camera shake correction unit will be described with reference to FIG.
First, the charging state detection unit 42 detects whether or not charging of the imaging device 100 has been started (step S101). At this time, when it is detected that charging of the imaging device 100 has not been started, the process returns to the original and waits (“No” in step S101).

  On the other hand, when the charging state detection unit 42 detects that charging of the imaging device 100 has started (“Yes” in step S101), the CPU 60 issues a calibration start command to the camera shake correction in the camera shake correction unit 50. It transmits to the control part 52. Normally, the imaging apparatus 100 is in an OFF state during charging. After being activated by the calibration start command, the camera shake correction unit 52 in the standby state energizes the camera shake correction unit 50 and activates it (step S102).

  Immediately after the start of energization, since the output voltage of the movement amount detection unit 53 is unstable, in order to avoid this, after waiting for a predetermined time (step S103), a buffer (not shown) in the work memory 54 is cleared (step S104). ), An acquisition count value is set in a counter (not shown) in the camera shake correction control unit 52 (step S105).

  Next, according to the camera shake correction control program read from the flash ROM 55 by the camera shake correction control unit 52, the output voltage from the gyro sensor is acquired from the movement amount detection unit 53 (step S106), and the acquired value is stored in the work memory 54. It adds to the buffer which is not illustrated (step S107). Then, the acquisition counter value of a counter (not shown) in the camera shake correction control unit 52 is decreased by one.

  At this time, it is confirmed whether or not the acquisition counter value of a counter (not shown) in the camera shake correction control unit 52 is “0” (step S109). If the acquisition counter value is not “0” (“No” in step S109). ) Further detects whether or not the charging of the imaging device 100 is terminated by the charging state detection unit 42 (step S110). When the charging state detection unit 42 detects that charging of the imaging device 100 has been completed (“Yes” in step S110), the process returns to step S101, and the charging state detection unit 42 causes the imaging device to When it is detected that the charging of 100 has not been completed (“No” in step S110), the process returns to step S106.

  On the other hand, if the acquisition counter value is “0” (“Yes” in step S109), the value in the buffer (not shown) in the work memory 54 is divided by the number of acquisitions set in the counter, and the value from the gyro sensor is obtained. The average value of the output voltage is calculated (step S111).

  Then, the calculated average value is compared with the reference voltage stored in the flash ROM 55 to determine whether or not the difference between the average value and the reference voltage value is equal to or smaller than a predetermined value (step S112). . At this time, if the difference between the average value and the reference voltage value is equal to or less than a predetermined value (“Yes” in step S112), the reference voltage value stored in the flash ROM 55 is calculated to the average value obtained. Update and store (step S113). Then, the camera shake correction unit 50 is turned off (step S114), and the calibration process is terminated. On the other hand, if the difference between the average value and the reference voltage value is not less than or equal to a predetermined value (“No” in step S112), the process returns to step S101.

  Therefore, according to the present embodiment, calibration of a shake detection element such as a gyro sensor is performed during charging of the imaging apparatus, so that calibration is performed at an appropriate timing. Can be kept high. Moreover, since charging is in progress, unstable factors such as battery voltage drop can be eliminated from calibration.

<Second Embodiment>
The second embodiment will be described with reference to FIG.
As shown in FIG. 4, in the camera shake correction unit according to the present embodiment, a charge state detection unit 42 and a camera shake correction control unit 52 are directly connected. That is, in the first embodiment, the charging state detection unit 42 notifies the CPU 60 of a detection result of whether or not charging of the imaging device 100 has been started or ended by a signal, and the CPU 60 has the charging state. In this embodiment, the calibration start command or the calibration end command is sent to the camera shake correction control unit 52 in the camera shake correction unit 50 according to the signal received from the detection unit 42 to control the start and end of the calibration. In the embodiment, the camera shake correction is performed by transmitting, for example, an “H level” signal or an “L level” signal directly from the charging state detection unit 42 to the camera shake correction control unit 52 in the camera shake correction unit 50 without using the CPU 60. The activation of the unit 50 is controlled.

  Therefore, according to the present embodiment, since the activation of the camera shake correction unit 50 can be directly controlled by a signal from the charge state detection unit without using the CPU, the activation time of the camera shake correction unit 50 is further shortened, and always High accuracy of camera shake correction can be maintained.

  Note that the imaging apparatus of the present invention can be realized by recording the processing of the imaging apparatus on a computer-readable recording medium, causing the imaging apparatus to read and execute a program recorded on the recording medium. The computer system here includes an OS and hardware such as peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW (World Wide Web) system is used. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes designs and the like that do not depart from the gist of the present invention.

It is a block diagram of the imaging device which concerns on 1st Embodiment. It is a block diagram of the camera-shake correction part which concerns on 1st Embodiment. 3 is a processing flow of a camera shake correction unit according to the first embodiment. It is a block diagram of the camera-shake correction part which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Key input part, 20 ... Strobe light emission part, 21 ... LCD, 30 ... Lens, 31 ... Lens drive block, 32 ... Shutter combined shutter, 40 ... CCD, DESCRIPTION OF SYMBOLS 41 ... Image processing part, 42 ... Charge state detection part, 43 ... External communication I / F (Interface), 44 ... Strobe drive part, 45 ... Recording medium, 46 ... Recording Media I / F (Interface), 47... Memory, 48... DRAM (Dynamic Random Access Memory), 50... Shake Correction Unit, 51... Actuator, 52. ... Moving amount detection unit, 54 ... Working memory, 55 ... Flash ROM, 60 ... CPU (Central Processing U) nit), 100 ... imaging device

Claims (6)

Detection means for detecting the state of charge;
Calibration execution means for calibrating the hand movement detection element;
Control means for controlling the start of calibration in the calibration execution means when the detection means detects the start of charging;
An imaging apparatus comprising: Obtaining a predetermined number of output values of the camera shake detection element, and calculating means for calculating an average value of the output values;
Difference determining means for determining whether or not a difference between the average value of the calculated output values and a reference voltage value is equal to or less than a predetermined value;
Updating means for updating the reference voltage value with the average value when the difference between the calculated average value of the output value and the reference voltage value is equal to or less than a predetermined value;
The imaging apparatus according to claim 1, further comprising:   The control means transmits a calibration start command or a calibration end command to the calibration execution means and controls the calibration execution means when the detection means detects that charging is started or stopped. The imaging apparatus according to claim 1 or 2, wherein   The control means controls the calibration execution means by transmitting a calibration start signal or a calibration end signal to the calibration execution means when the detection means detects that charging is started or stopped. The imaging apparatus according to claim 1 or 2, wherein A method for performing calibration of a camera shake detection element in an imaging apparatus,
A first step of detecting a charging state of the imaging device body;
A second step of activating a camera shake correction module when detecting the start of charging;
A third step of obtaining a predetermined number of output values of the camera shake detection element and calculating an average value of the output values;
A fourth step of determining whether or not a difference between the average value of the calculated output values and a reference voltage value is a predetermined value or less;
When the difference between the average value of the calculated output value and the reference voltage value is equal to or less than a predetermined value, the reference voltage value is updated with the average value, and the difference between the calculated average value of the output value and the reference voltage value is A fifth step of returning the processing to the first step when greater than a predetermined value;
A method for performing calibration of a camera shake detection element, comprising: A program for causing a computer in the imaging apparatus to execute calibration of a camera shake detection element in the imaging apparatus,
A first step of detecting a charging state of the imaging device body;
A second step of activating a camera shake correction module when detecting the start of charging;
A third step of obtaining a predetermined number of output values of the camera shake detection element and calculating an average value of the output values;
A fourth step of determining whether or not a difference between the average value of the calculated output values and a reference voltage value is a predetermined value or less;
When the difference between the average value of the calculated output value and the reference voltage value is equal to or less than a predetermined value, the reference voltage value is updated with the average value, and the difference between the calculated average value of the output value and the reference voltage value is A fifth step of returning the processing to the first step when greater than a predetermined value;
A program that causes a computer to execute.

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