JP4594004B2 - IMAGING DEVICE, ITS CONTROL METHOD, PROGRAM, AND STORAGE MEDIUM - Google Patents

Description

The present invention relates to an imaging apparatus , a control method thereof, a program, and a storage medium, and more particularly, to an imaging apparatus having a zoom mechanism and a camera shake stabilization mechanism , a control method thereof, a program, and a storage medium.

A digital camera as a conventional imaging device includes a zoom mechanism having a zoom lens group. In this zoom mechanism, there may be a deviation between the center position and the optical axis for each zoom position of the zoom lens group, or an image shake that causes the image to shake during the zoom operation. Among the digital cameras, which are miniaturized, the zoom mechanism has a high-magnification retractable lens barrel, and the deviation between the center position and the optical axis that occurs at each zoom position of the zoom lens group is even greater.

On the other hand, there is a camera having a camera shake stabilization mechanism that changes the angle of view by shifting the position of a shift lens provided in the zoom mechanism in response to vibration from the outside. In this camera, the shift lens is moved so as to have an angle of view set for each zoom position, and the shift of the center position and the image shake are corrected (for example, see Patent Document 1).
JP-A-7-203281 (page 20, FIG. 6)

However, when the optical axis deviates for each zoom position, not only the center position of the zoom lens group but also the lens characteristics such as the peripheral light amount change. Further, at the time of capturing a moving image and a still image, since the required image quality is different respectively, for example, when the still image shooting is performed under the setting that matches the moving image shooting, want physician quality of the captured image is deteriorated In still image shooting, image quality was most important, and in moving image shooting, not only image quality but also image movement could not be taken.

The purpose of the present invention is to correct the lens characteristics of the zoom lens group generated at each zoom position, for example, the shift of the center position and the peripheral light amount, placing the highest priority on image quality when shooting still images, and only the image quality when shooting moving images. It is another object of the present invention to provide an imaging apparatus , a control method thereof, a program, and a storage medium that can record a high-quality image by performing shooting noting image movement as important .

In order to achieve the above object, an imaging apparatus according to claim 1 is an imaging apparatus having a still image shooting mode for shooting a still image and an operation shooting mode for shooting a moving image, and has a plurality of lens characteristics. a magnification lens group, and a driving means for driving the lens group, an optical axis moving means for moving the optical axis position of the lens group, and at least the center position of the lens group among the plurality of lens characteristics of the lens and a lens characteristic detecting means for detecting the amount of peripheral light, the driving means, the lens is driven to a plurality of predetermined positions, wherein the optical axis moving means, the predetermined plural when said still image capturing mode based on the peripheral light amount of the lens group to adjust the optical axis position for each position, adjusting the optical axis position based on the center position of the lens unit for each of the plurality of predetermined positions when the moving image shooting mode Optical axis adjusting means, optical axis position storing means for storing the adjusted optical axis position for each of the plurality of predetermined positions, and the optical axis based on the stored optical axis positions at the plurality of predetermined positions. And an optical axis correcting means for correcting the position.

According to the imaging apparatus of the first aspect, it is possible to take a picture with the highest priority on image quality when shooting a still image, and with a focus on not only the image quality but also the movement of an image when shooting a moving image. Images can be recorded.

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

  FIG. 1 is a block diagram schematically showing the configuration of an image recording apparatus according to an embodiment of the present invention.

  In FIG. 1, a digital camera 100 as an image recording apparatus includes a zoom unit 101 that performs zooming, a shift lens unit 103 that changes an angle of view, an aperture / shutter unit 105 that determines an exposure amount, and a focus adjustment. A focus unit 107 to perform, a zoom unit 101, a shift lens unit 103, an aperture / shutter unit 105, and an imaging unit 109 that converts an optical image of a subject received through the focus unit 107 into an electrical signal.

  The digital camera 100 also includes an imaging signal processing unit 110 that converts the electrical signal sent from the imaging unit 109 into a video signal, and a video that processes the video signal sent from the imaging signal processing unit 110 according to the application. A signal processing unit 111, a display unit 112 that displays a signal transmitted from the video signal processing unit 111 as necessary, a power source unit 113 that supplies power according to the application, communication with the outside, and input of a video signal An external input / output terminal unit 114 that performs output, an operation unit 115 that operates the digital camera 100, a storage unit 116 that stores data such as video information, and a zoom drive control unit 102 that drives the zoom unit 101 (magnification unit) ), A shift lens drive controller 104 for driving the shift lens unit 103, and an aperture / shutter for driving the aperture / shutter unit 105. A drive control unit 106, a focus drive control unit 108 that drives the focus unit 107, and a control unit 117 that controls processing of the digital camera 100, a zoom drive control unit 102, a shift lens drive control unit 104, an aperture / shutter Drive unit 106, focus drive control unit 108, power supply unit 113, external input / output terminal unit 114, operation unit 115, storage unit 116, imaging signal processing unit 110 connected to imaging unit 109, video signal processing unit 111, and display The units 112 are connected to the control unit 117, respectively.

  Upon receiving an instruction for zooming magnification from the operation unit 115, the control unit 117 causes the zoom drive control unit 102 to move the zoom unit 101 to a desired position, and the imaging unit 109, the imaging signal processing unit 110, and the video signal processing unit 111. The focus drive control unit 108 drives the focus unit 107 to adjust the focus based on the image information received from.

  When the control unit 117 further receives a shooting instruction from the operation unit 115, the control unit 117 drives the aperture / shutter drive unit 106 to adjust the exposure amount, and the light exposed to the imaging unit 109. The image information of the image is stored in the storage unit 116.

  At this time, when the control unit 117 receives an instruction to turn on the image stabilization control from the operation unit 115, the control unit 117 causes the shift lens drive control unit 104 to drive the shift lens unit 103 and receives an instruction to turn off the image stabilization control. Until the image stabilization control process is performed.

  Further, the still image mode or the moving image mode can be selected as the operation mode of the digital camera 100, and the operation condition of each drive control unit can be changed in each mode.

  FIG. 2 is a block diagram schematically showing the configuration of the shift lens drive controller 104 in FIG.

  The shift lens drive control unit 104 in FIG. 2 outputs a position command signal according to the situation to perform the image stabilization control and the shift lens position control, and a vertical direction (pitch in the normal position of the digital camera 100. A gyro 202 that detects vibration in the direction) and outputs the detected vibration information, and a gyro 203 that detects vibration in the horizontal direction (yaw direction) at the normal position of the digital camera 100 and outputs the detected vibration information. Is provided.

  The shift lens drive control unit 104 also detects a magnetic field generated by a magnet attached to the shift lens unit 103 to detect the position of the shift lens unit 103 in the pitch direction and the yaw direction, and outputs a detected position signal. Elements 204 and 205, an amplifier 206 that amplifies the position signal output from the Hall element 204, and a comparator that compares the position command signal output from the image stabilization controller 201 and the Hall amplifier output output from the amplifier 206. 208, a filter 210 that filters the signal output from the comparator 208, a drive unit 213 that drives the shift lens unit 103 based on the filter output output from the filter 210, and a position signal output from the Hall element 205. From the amplifier 207 to be amplified and the image stabilization control unit 201 Based on the comparator 209 that compares the received position command signal with the Hall amplifier output that is output from the amplifier 207, the filter 211 that filters the signal that is output from the comparator 209, and the filter output that is output from the filter 211. And a drive unit 214 (optical axis moving means) for driving the shift lens unit 103.

  The image stabilization control unit 201 outputs a position command signal based on the vibration information in the pitch direction and yaw direction output from the gyros 202 and 203, and performs feedback position control so that the Hall amplifier output matches the position command signal output. The shift lens unit 103 is driven in the respective directions by the drive units 213 and 214.

The output value of the position command signal output by the image stabilization control unit 201 has a linear relationship with the Hall amplifier output within the movable range of the shift lens unit 103 (FIG. 3), and the center of the movable range of the shift lens unit 103 is Since the center position of the shift lens unit 103 is set, the Hall amplifier output is the median value V _c of the Hall amplifier outputs V _max and V _min when the shift lens unit 103 is positioned at the upper and lower limits of the mechanical end in the pitch direction. The position command signal output value D _c when (= (V _max + V _min ) / 2) is obtained, and this value is stored in the image stabilization controller 201 as an adjustment value, thereby adjusting the lens center position in the pitch direction. Is done.

  Similarly, the lens center position adjustment in the yaw direction is also performed.

  The shift of the center position at each zoom position of the zoom unit 101 is smaller when the lens center position adjustment is performed in a state where the zoom unit 101 is positioned at the telephoto end having the largest variable magnification. In this embodiment, the lens center position adjustment is performed. However, the lens center position adjustment is performed in a state where the zoom unit 101 is positioned at the wide end where the variable magnification is the smallest. Then, the zoom unit 101 is positioned at the wide end to adjust the lens center position.

  Further, since the center position of the zoom unit 101 changes with the movement of the zoom unit 101 accompanying the zoom operation (FIG. 4A), even during a zoom operation, the image shakes even for a stationary subject.

  In order to correct this, after the zoom unit 101 is positioned at the wide end (N0) and the lens center position is adjusted, the lens center position is viewed while viewing the captured image at each predetermined zoom position (N0 to N8). Adjustments are made.

  The lens center position adjustment at each predetermined zoom position is performed, for example, by photographing the chart paper 500 shown in FIG. 5, and the lens center position adjustment is performed by positioning the zoom unit 101 at the wide end (N0). After that, the pitch on the captured image of the chart paper 500 and the position of the white and black boundary line in the yaw direction (horizontal boundary line in the pitch direction and vertical boundary line in the yaw direction) are stored, At the zoom positions (N0 to N8), the shift lens unit 103 is moved in the pitch and yaw directions, and the output value of the position command signal whose center position becomes the stored boundary position is obtained for each predetermined zoom position. (Optical axis adjustment means), this value is stored as an adjustment value in the image stabilization control unit 201 (optical axis position storage means).

  In the product state, the image stabilization control unit 201 determines the position command based on the relationship between each predetermined zoom position (N0 to N8) shown in Table 1 below and the output value of the position command signal that is the stored adjustment value. By outputting a signal and driving the shift lens unit 103, the deviation of the center position is corrected (optical axis correcting means).

さらに、ズームユニット１０１が、所定の各ズーム位置の間に位置するときは、防振制御部２０１は、リニア補間によりズームユニット１０１の位置に対応する位置指令信号の出力値が求められ（光軸位置算出手段）、シフトレンズユニット１０３を駆動させる。

Further, when the zoom unit 101 is positioned between predetermined zoom positions, the image stabilization control unit 201 obtains an output value of a position command signal corresponding to the position of the zoom unit 101 by linear interpolation (optical axis). Position calculating means), and the shift lens unit 103 is driven.

Assume that the zoom stop position is n, the predetermined zoom positions at both ends are N _x and N _{x + 1,} and the output values of the position command signals corresponding to N _x and N _{x + 1} are D _x and D _{x + 1} , respectively (FIG. 7). ), The image stabilization control unit 201 outputs the output value D _n of the position command signal of the shift lens unit 103 at the zoom position _n using the following equation (1):
_{D n = (n-N x} + 1) / (N x + 1 -N x) × (D x + 1 -D x) + D x ... (1)
And the output value D _n of the calculated position command signal is output and the shift lens unit 103 is driven to correct the deviation of the center position when the zoom unit 101 is located at a position other than the predetermined zoom positions. .

  Similarly, the deviation of the center position is corrected for the yaw direction.

  Further, the image stabilization control unit 201 performs the image stabilization operation based on the adjusted adjustment value.

  According to the shift lens control unit 104 of FIG. 2, the image stabilization control unit 201 outputs a position command signal based on the relationship between each predetermined zoom position and the output value of the position command signal that is a stored adjustment value. Since the shift lens unit 103 is output and the shift lens unit 103 is driven, the shift of the center position of the zoom unit 101 occurring at each predetermined zoom position can be corrected, and a high-quality image can be recorded.

  FIG. 8 is an image taken by the digital camera 100 of FIG. 1 and is a diagram used to explain an image when shading correction is performed based on the amount of light around the four corners. (B) shows the case where the peripheral light amounts at the four corners are non-uniform.

  The image in FIG. 8 is obtained when a peripheral light amount drop (shading) occurs in which the four corners of the captured image become dark because the transmittance of the lens decreases with increasing distance from the center of the lens.

  The influence of shading is strong when the zoom unit 101 is located on the wide side, and is weak when the zoom unit 101 is located on the tele side.

  Even if the center position of the zoom unit 101 is correct, the shading state changes depending on the state of the lens group (FIG. 8B), and the image quality may be deteriorated. It is preferable that the peripheral light amount is uniform (FIG. 8A).

  Therefore, the zoom unit 101 is positioned at the wide end (N0), and the four corner areas (FIG. 9) of the captured image when the white chart is captured in an appropriate exposure state are extracted, and the shading information of the four extracted images and The shift lens unit 103 is driven so that the luminance levels become the same, and the output values of the pitch and yaw direction position command signals at that time are stored in the image stabilization control unit 201 as adjustment values.

  Further, after the shading adjustment is performed in a state where the zoom unit 101 is positioned at the wide end (N0), the shading information is detected at the predetermined zoom position to similarly perform the shading adjustment, and the obtained position The output value of the command signal is stored in the image stabilization control unit 201 as an adjustment value.

  In the product state, the image stabilization control unit 201 outputs a position command signal based on the relationship between each predetermined zoom position (N0 to N8) and the output value of the position command signal that is the stored adjustment value. Then, the shading correction is performed by driving the shift lens unit 103. Further, when the zoom unit 101 is positioned between the predetermined zoom positions, the image stabilization control unit 201 calculates an output value of a position command signal corresponding to the position of the zoom unit 101 by linear interpolation, and calculates the calculated position command signal. Is output to drive the shift lens unit 103 to perform shading correction. As a result, the shading at each predetermined zoom position can be corrected to obtain an optimum shading state, and a high-quality image can be recorded.

  In still image shooting, image quality is most important. In moving image shooting, not only image quality but also image movement is important. For example, in still image recording, it is required that the shading is uniform, but when the zoom operation is performed during moving image recording, it is required that the image center does not shift.

  In order to achieve both of these, in the moving image mode, the shift lens unit 103 is driven so that the center position of each zoom position is obtained by adjusting the lens center position so that the center position does not shift during the zoom operation (see FIG. 6) The shift lens unit 103 may be driven so that the position obtained by the shading correction is set for each zoom position so that the balance of shading is not shifted during the zoom operation (FIG. 8).

  Another object of the present invention is to supply a storage medium (or recording medium) on which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (or CPU or CPU) of the system or apparatus. Needless to say, this can also be achieved by the MPU) reading and executing the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the storage medium is written to a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the card or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  The above-described program only needs to be able to realize the functions of the above-described embodiments by a computer, and the form includes forms such as object code, a program executed by an interpreter, and script data supplied to the OS. But you can.

  As a recording medium for supplying the program, for example, RAM, NV-RAM, floppy (registered trademark) disk, optical disk, magneto-optical disk, CD-ROM, MO, CD-R, CD-RW, DVD (DVD-ROM, DVD-RAM, DVD-RW, DVD + RW), magnetic tape, non-volatile memory card, other ROM, etc. may be used as long as they can store the above programs. Alternatively, the program is supplied by downloading from another computer or database (not shown) connected to the Internet, a commercial network, a local area network, or the like.

1 is a block diagram schematically showing a configuration of an image recording apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram schematically showing a configuration of a shift lens drive control unit in FIG. 1. It is a graph which shows the relationship between the output value of the position command signal which the image stabilization control part in FIG. 2 outputs, and the Hall amplifier output which an amplifier outputs. 2 is a graph showing a shift of a center position at each predetermined zoom position of the zoom unit in FIG. 1, (a) is a pitch direction and a yaw direction, (b) is a pitch direction, and (c) is a shift with respect to the yaw direction. Show. It is a figure used for demonstrating the chart used when adjusting the center position of the zoom unit in FIG. 2 is a graph showing a relationship between each predetermined zoom position of the zoom unit in FIG. 1 and an output value of a position command signal which is an adjustment value obtained by adjusting the lens center position. FIG. 2 is a diagram used for describing linear interpolation of an output value of a position command signal, which is an adjustment value obtained by adjusting the lens center position with respect to each predetermined zoom position of the zoom unit in FIG. 1. FIG. 2 is an image taken by the digital camera of FIG. 1 and is used to explain an image when shading correction is performed based on peripheral light amounts at the four corners. FIG. (B) shows the case where the peripheral light amounts at the four corners are non-uniform. It is a figure used for explaining shading correction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Digital camera 101 Zoom unit 102 Zoom drive control part 103 Shift lens unit 104 Shift lens drive control part 117 Control part 201 Anti-vibration control part 202 Gyro 203 Gyro 213 Drive part 214 Drive part 204 Hall element 205 Hall element

Claims (6)

An imaging apparatus having a still image shooting mode for shooting a still image and an operation shooting mode for shooting a movie,
A variable power lens group having a plurality of lens characteristics;
Driving means for driving the lens group;
An optical axis moving means for moving the optical axis position of the lens group ;
And a lens characteristic detecting means for detecting the peripheral light amount of at least the lens and the center position of the lens group among the plurality of lens characteristics,
The driving means drives the lens group to a plurality of predetermined positions,
The optical axis moving means is
In the still image shooting mode, the optical axis position is adjusted based on the peripheral light amount of the lens group for each of the plurality of predetermined positions. In the moving image shooting mode, the lens group is adjusted for each of the plurality of predetermined positions. An optical axis adjusting means for adjusting the optical axis position based on a center position ;
Optical axis position storage means for storing the adjusted optical axis position for each of the plurality of predetermined positions;
An imaging apparatus comprising: an optical axis correction unit that corrects the optical axis position based on the stored optical axis positions at the plurality of predetermined positions. The imaging apparatus according to claim 1 , wherein the optical axis correction unit includes an optical axis position calculation unit that calculates an optical axis position of the lens group at a position other than the plurality of predetermined positions by an interpolation method. Further comprising shake detection means for detecting shake applied to the imaging device;
The optical axis moving means, imaging apparatus according to claim 1 or 2, wherein the reducing the image blur due to shake the based on an output of said shake detecting means. A method for controlling an imaging apparatus having a still image shooting mode for shooting a still image and an operation shooting mode for shooting a moving image,
A driving step for driving a variable magnification lens group having a plurality of lens characteristics;
An optical axis moving step for moving the optical axis position of the lens group ;
A lens characteristic detection step of detecting at least a center position of the lens group and a peripheral light amount of the lens group among the plurality of lens characteristics;
The driving step drives the lens group to a plurality of predetermined positions,
The optical axis moving step includes
In the still image shooting mode, the optical axis position is adjusted based on the peripheral light amount of the lens group for each of the plurality of predetermined positions. In the moving image shooting mode, the lens group is adjusted for each of the plurality of predetermined positions. An optical axis adjustment step for adjusting the optical axis position based on a center position ;
An optical axis position storing step of storing the adjusted optical axis position for each of the plurality of predetermined positions;
An optical axis correction step of correcting the optical axis position based on the stored optical axis positions at the plurality of predetermined positions. A program for executing a control method of an imaging apparatus having a still image shooting mode for shooting a still image and an operation shooting mode for shooting a moving image, the control method comprising:
A driving step for driving a variable magnification lens group having a plurality of lens characteristics;
An optical axis moving step for moving the optical axis position of the lens group ;
A lens characteristic detection step of detecting at least a center position of the lens group and a peripheral light amount of the lens group among the plurality of lens characteristics;
The driving step drives the lens group to a plurality of predetermined positions,
The optical axis moving step includes
In the still image shooting mode, the optical axis position is adjusted based on the peripheral light amount of the lens group for each of the plurality of predetermined positions. In the moving image shooting mode, the lens group is adjusted for each of the plurality of predetermined positions. An optical axis adjustment step for adjusting the optical axis position based on a center position ;
An optical axis position storing step of storing the adjusted optical axis position for each of the plurality of predetermined positions;
An optical axis correction step of correcting the optical axis position based on the stored optical axis positions at the plurality of predetermined positions. A computer-readable storage medium storing the program according to claim 5 .

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