JP2007071905A - Imaging apparatus and method for controlling the imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of obtaining high-quality images by always securing proper exposure in consecutive photographing. <P>SOLUTION: The imaging apparatus has an imaging device 20; a diaphragm means 16 changing the amount of luminous flux reaching the imaging device 20; a shutter means 18 intercepting the luminous flux reaching the imaging element 20; a recording means 54 storing the deviation of a diaphragm value of the diaphragm means 16 which changes, according to the number of times of the consecutive driving of the shutter means 18; and a correction means 56 correcting the shutter speed of the shutter means 18 by using a value recorded in the recording means 54. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to iris diaphragm deviation correction during continuous shooting.

  2. Description of the Related Art In recent years, an image pickup apparatus configured to cause an image pickup device such as a CCD to pick up an image by an optical photographing unit and store image data output from the image pickup device in a recording element has been put into practical use. Among such image pickup apparatuses, there is an apparatus in which a photographer can obtain an appropriate exposure by setting an aperture value and a shutter speed.

  In addition, as disclosed in Japanese Patent Application Laid-Open No. H10-227707, there is a camera that can automatically set a proper exposure by comparing luminance information of a subject obtained by a photometry unit with a pre-recorded program diagram. In addition, there is a camera that can perform continuous shooting (bracket shooting) by changing the exposure slightly before and after the appropriate exposure set as described above. (Patent Document 2)

  In the image pickup apparatus, the exposure varies depending on the combination of the shutter speed, the aperture value, and the ISO sensitivity. The iris diaphragm mechanism used in a general image pickup apparatus is described below with reference to FIG. explain.

  In FIG. 7A, the iris diaphragm mechanism will be described. The iris diaphragm is composed of a plurality of wings 100 and a rotating ring 106 that is a driving source of the wings 100. Each wing 100 is stopped by a support shaft 102 which is the wing rotation center. The wing 100 is provided with a wing pin hole 104. A rotating ring pin 108 is implanted in the rotating ring 106 and is inserted through the wing pin hole 104. For example, the iris diaphragm is opened by rotating the rotating ring 106 clockwise, and is closed by rotating counterclockwise.

  In such an iris diaphragm mechanism, the diameter of the wing pin hole 104 is larger than the diameter of the rotary ring pin 108. In addition to intentionally designed margins, gaps due to solid variability occur as unique values. Usually, in order to hold down this gap, for example, an elastic means such as a spring is used, and when the iris diaphragm is driven, the rotary ring pin 108 with respect to the wing pin hole 104 is biased in a predetermined direction. (FIG. 7C) As a result, an appropriate exposure set in advance is obtained without depending on the gap.

JP-A 63-205644 JP-A-4-29125

In an imaging apparatus having a conventional iris diaphragm, when continuous shooting is performed, the aperture value may be shifted due to the continuous driving.
For example, in the iris diaphragm shown in FIG. 7, the rotation of the rotary ring pin 108 with respect to the wing pin hole 104 cannot be maintained without moving the rotary ring 106 due to the vibration caused by the continuous drive, and the diaphragm shift occurs as it is (FIG. 7). (B)). As a result, the appropriate exposure set in advance cannot be obtained, so that the images are different due to the change in the depth of field.

  In view of such circumstances, an object of the present invention is to provide an imaging apparatus and an imaging apparatus control method capable of always ensuring proper exposure and obtaining a high-quality image even during continuous shooting.

  The present invention relates to an imaging device, a diaphragm unit that changes an amount of a light beam that reaches the image sensor, a shutter unit that blocks a light beam that reaches the image sensor, and a diaphragm unit that changes according to the number of times the shutter unit is continuously driven. The imaging apparatus includes a correcting unit that corrects the deviation of the aperture value.

  The present invention relates to a method for controlling an image pickup apparatus, comprising: an image pickup device; an aperture means for changing the amount of light flux reaching the image pickup device; and a shutter means for shielding the light flux reaching the image pickup device. It has a correction process which corrects deviation of the aperture value of the aperture means which changes according to the number of times.

  According to the present invention, the correlation between the number of continuous photographing and the aperture deviation is measured, and the photographing condition is changed for each number of photographing, thereby enabling photographing with correction of the diaphragm deviation and obtaining an appropriate exposure.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram of an image processing apparatus. In FIG. 1, reference numeral 10 denotes a photographing lens protection means. A barrier control unit 62 controls the operation of the lens protection means 10. Reference numeral 12 denotes a zoom lens. A zoom control unit 60 controls the zoom lens 12 to change the magnification. Reference numeral 14 denotes a focus lens. A focus control unit 58 controls the focus lens 14 to perform focusing.

  Reference numeral 16 denotes an iris diaphragm. Reference numeral 50 denotes an aperture control unit that controls the aperture driver 48 in accordance with the aperture value. The aperture driver 48 supplies a predetermined drive voltage to the stepping motor 46 to open and close the aperture. Reference numeral 18 denotes a shutter. A shutter control unit 44 controls the shutter driver 42 in accordance with the shutter speed. The shutter driver 42 supplies a predetermined driving current to the electromagnetic magnet 40 to open / close the shutter.

  Reference numeral 20 denotes an image sensor (also having a photometric function) that changes an optical image into an electrical signal. Reference numeral 22 denotes a CDS (correlated double sampling circuit), which is a circuit for reducing noise with respect to the image sensor 20. An AGC amplifier 24 corrects the signal sampled by the CDS 22. In this case, increasing the gain of the AGC amplifier 24 increases the ISO sensitivity of the image sensor 20, and decreasing the gain decreases the ISO sensitivity of the image sensor 20.

  A timing generator 26 supplies a clock signal to the image sensor 20, DA converter 28, and AD converter 32. A memory control unit 34 controls the timing generation unit 26, the DA conversion unit 28, the AD conversion unit 32, the image display unit 36, and the image processing unit 38.

  An image processing unit 38 performs predetermined pixel interpolation processing and color conversion processing on the data from the AD conversion unit 32 or the data from the memory control unit 34. The data of the AD conversion unit 32 is written into the image display storage unit 36 via the image processing unit 38, the memory control unit 34, or directly via the memory control unit 34. The display image data written in the image display storage unit 36 is displayed from the image display unit 30 via the DA conversion unit 28. An electronic viewfinder function can be realized by sequentially displaying image data captured using the image display unit 30.

A camera system control unit 74 controls the shutter control unit 44, the aperture control unit 50, the focus control unit 58, the zoom control unit 60, and the barrier control unit 62. Reference numeral 72 denotes a memory having a storage capacity sufficient to store a predetermined number of still images and a moving image for a predetermined time.
The memory 72 can also be used as a work area for the camera system control unit 74. Reference numeral 66 denotes an interface with a recording medium such as a memory card or a hard disk.

  Reference numeral 70 denotes a power source, which includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like, detects whether or not a battery is installed, the type of battery, the remaining battery level, The DC-DC converter is controlled based on an instruction from the camera system control unit 74, and a necessary voltage is supplied to each unit including a recording medium for a necessary period. Reference numeral 68 denotes a recording unit, which accesses the camera system control unit 74 via the interface 66.

  64 is an operation unit composed of various buttons, a touch panel, etc., a menu button, a set button, a macro button, a multi-screen playback page break button, a flash setting button, a single shooting / continuous shooting / self-timer switching button, menu movement + (plus) Buttons, menu movement- (minus) button, reproduction image movement + (plus) button, reproduction image- (minus) button, shooting image quality selection button, exposure correction button, and the like. Reference numeral 52 denotes a photometric unit, which measures the luminance of the subject by the image sensor 20 (also having a photometric function). Reference numeral 56 denotes an aperture deviation correction unit, and reference numeral 54 denotes an aperture deviation correction table.

  FIG. 2 is a table showing the relationship between the number of times of continuous shooting and the aperture value at a predetermined light amount in the imaging apparatus having the above configuration. FIG. 2 shows the result of measuring the aperture deviation amount for each continuous shooting number by the photometry unit 52 in advance. When an aperture value is given for a predetermined amount of light, the shutter speed is calculated. Therefore, the shutter speed corresponding to the aperture deviation is determined.

  Next, FIG. 3 shows the relationship between the number of continuous shooting and the shutter speed for correcting the aperture deviation at a predetermined light amount calculated by a known equation. The numerical values in FIG. 3 are stored in the aperture deviation correction table 54 as shutter speeds corresponding to one-to-one with respect to the number of continuous photographing. The aperture deviation correction unit 56 uses the aperture deviation correction table 54 to send an appropriate shutter speed command to the shutter control unit 44 every number of consecutive photographing.

  FIG. 4 is a table showing the relationship between the number of continuous shooting and the ISO sensitivity for correcting the aperture deviation at a predetermined light amount. The numerical values in FIG. 4 are stored in the aperture deviation correction table 54 as effective ISO sensitivity corresponding to the number of continuous photographing. The aperture deviation correction unit 56 can appropriately send an ISO sensitivity command to the AGC amplifier 24 every number of continuous photographing using the aperture deviation correction table 54.

Next, an example of a specific imaging method in the imaging apparatus will be described.
First, FIG. 5 is a flowchart of the aperture deviation correction process by changing the shutter speed.

  Correction processing is started by changing the shutter speed of the aperture deviation when shooting is started in step S502. The camera system control unit 74 gives a shooting start command to the aperture deviation correction unit. Step S504 is an initialization process for substituting 1 into the continuous shooting number counter N.

  In step S506, it is determined whether the number of continuous shooting is within a correctable range. If the continuous shooting number N is equal to or greater than the correction start number and equal to or less than the correction end number, the process proceeds to step S514. If the determination is other than this determination, the process proceeds to step S508.

  In step S508, if the number of continuous shooting is less than the correctable range, the process proceeds to the process of step S512, that is, the process of not performing aperture deviation correction. In cases other than this determination in step S508, it means that the number of continuous shooting is larger than the correctable range, and therefore, the maximum correction, that is, the maximum shutter speed correction is performed as the aperture deviation correction.

  If the number of continuous shooting is within the correctable range in step S506, the process proceeds to step S514. In step S514, an aperture deviation correction table (referred to as an all-measurement type aperture deviation correction table) in which aperture deviation correction is measured in advance every predetermined number of continuous shootings is used, or a predetermined number of continuous shooting times is limited to several points in advance. In the meantime, it is determined whether to use an aperture deviation correction table (referred to as an interpolation type aperture deviation correction table) calculated by linear interpolation. The all-measurement type aperture deviation correction table and the interpolation type aperture deviation correction table are stored in the aperture deviation correction table 54.

  When the interpolation type aperture deviation correction table is used, the corresponding shutter speed is selected from the interpolation type aperture deviation correction table in step S518 and notified to the shutter control unit 44 to correct the aperture deviation.

  When using the all-measurement type aperture deviation correction table, the corresponding shutter speed is selected from the all-measurement type aperture deviation correction table in step S516 and notified to the shutter control unit 44 to perform aperture deviation correction.

  In step S520, it is determined whether or not continuous shooting is finished. If the continuous shooting is not completed, the number of continuous shooting is added once in step S522, and the process returns to the determination before step S506. If it is determined in step S520 that continuous shooting has ended, the aperture correction process ends in step S524.

  As described above, by correcting the shutter speed, it is possible to shoot with corrected aperture deviation during continuous shooting, and obtain an appropriate exposure.

FIG. 6 is a flowchart of the aperture deviation correction process by changing the ISO sensitivity. Next, FIG. 6 will be described as a second embodiment.
Correction processing by changing the ISO sensitivity of the aperture deviation when shooting is started in step S602 is started. The camera system control unit 74 gives a shooting start command to the aperture deviation correction unit. Step S604 is an initialization process for substituting 1 into the continuous shooting number counter N.

  In step S606, it is determined whether the number of continuous shooting is within a correctable range. If the continuous shooting number N is equal to or greater than the correction start number and equal to or less than the correction end number, the process proceeds to step S614. If the determination is other than this determination, the process proceeds to step S608.

  In step S608, when the number of continuous photographing is less than the correctable range, the process proceeds to the process of step S612, that is, the process of not performing aperture deviation correction. In step S608, in cases other than this determination, it means that the number of continuous shootings is larger than the correctable range, so the maximum correction, that is, the maximum ISO sensitivity correction is performed as the aperture deviation correction.

  If the number of continuous shooting is within the correctable range in step S606, the process proceeds to step S614. In step S614, an aperture deviation correction table (referred to as an all-measurement type aperture deviation correction table) in which aperture deviation correction is measured in advance every predetermined number of continuous shootings is used, or a predetermined number of continuous shooting times is limited to several points in advance. In the meantime, it is determined whether to use an aperture deviation correction table (referred to as an interpolation type aperture deviation correction table) calculated by linear interpolation. The all-measurement type aperture deviation correction table and the interpolation type aperture deviation correction table are stored in the aperture deviation correction table 54.

  When using the interpolation type aperture deviation correction table, the corresponding ISO sensitivity is selected from the interpolation type aperture deviation correction table in step S618 and notified to the AGC amplifier 24 to perform aperture deviation correction.

  When using the all-measurement-type aperture deviation correction table, the corresponding ISO sensitivity is selected from the all-measurement-type aperture deviation correction table in step S616, notified to the AGC amplifier 24, and aperture deviation correction is performed.

  In step S620, it is determined whether or not continuous shooting is finished. If the continuous shooting is not completed, the number of continuous shooting is added once in step S622, and the process returns to the determination before step S606. If it is determined in step S620 that continuous shooting has ended, the aperture correction process ends in step S624.

  As described above, by changing the ISO sensitivity, it is possible to shoot with corrected aperture deviation during continuous shooting, and obtain an appropriate exposure.

  An object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in.

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

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (basic system or operating system) running on the computer based on the instruction of the program code. Needless to say, a case where the functions of the above-described embodiment are 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 board 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 board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

It is a block diagram which shows the structure of the imaging device which concerns on suitable embodiment of this invention. It is a figure which shows the relationship of the aperture value which concerns on suitable embodiment of this invention. It is a figure which shows the relationship of the aperture shift which concerns on suitable embodiment of this invention. It is a figure which shows the relationship of the aperture shift which concerns on suitable embodiment of this invention. 3 is a flowchart according to a preferred embodiment of the present invention. 3 is a flowchart according to a preferred embodiment of the present invention. It is a figure which shows the structural example of the iris diaphragm in an imaging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shooting lens protection means 12 Zoom lens 14 Focus lens 16 Iris diaphragm 18 Shutter 20 Image sensor and photometric element 22 CDS
24 AGC amplifier 26 Timing generation unit 28 DA conversion unit 30 Image display unit 32 AD conversion unit 34 Memory control unit 36 Image display storage unit 38 Image processing unit 40 Electromagnetic magnet 42 Shutter driver 44 Shutter control unit 46 Stepping motor 48 Aperture driver 50 Aperture Control unit 52 Metering unit 54 Aperture deviation correction table 56 Aperture deviation correction unit 58 Focus control unit 60 Zoom control unit 62 Barrier control unit 64 Operation unit 66 I / F
68 Storage Unit 70 Power Supply 72 Memory 74 Camera System Control Unit 100 Wings 102 Wings Rotation Center 104 Wings Pin Hole 106 Rotating Ring 108 Rotating Ring Pin

Claims (8)

An image sensor;
Stop means for changing the amount of the light beam reaching the image sensor;
Shutter means for shielding the light beam reaching the image sensor;
An image pickup apparatus comprising: a correction unit that corrects a deviation of an aperture value of the aperture unit that changes in accordance with the number of times the shutter unit is continuously driven.   The imaging apparatus according to claim 1, wherein the correction unit corrects a deviation of an aperture value of the aperture unit by changing a shutter speed of the shutter unit.   The imaging apparatus according to claim 1, wherein the correcting unit corrects a deviation of an aperture value of the aperture unit by changing an amplification factor of an output signal of the imaging element.   Storage means for storing a value corresponding to a deviation of the aperture value of the aperture means that changes in accordance with the number of times the shutter means is continuously driven, and the correction means uses the value stored in the storage means to The imaging apparatus according to any one of claims 1 to 3, wherein a deviation of an aperture value of the means is corrected.   5. The imaging apparatus according to claim 4, wherein the storage unit creates and stores a shooting count-aperture value deviation correspondence table by measuring a relationship between each continuous shooting count and a photometric amount in advance.   The storage unit measures in advance a light amount of light at a first continuous shooting number of times one or more and a light amount of light at a second continuous number of shooting times greater than the first continuous shooting number, and between the first and second continuous shooting times. The imaging apparatus according to claim 4, wherein a corresponding aperture value deviation is calculated by linear interpolation to create and store a photographing frequency-aperture value deviation correspondence table.   The aperture value correction start count and correction end count are set in advance, and the aperture value deviation with respect to each continuous shooting count is corrected only at the number of shooting times greater than or equal to the correction start count and the number of shooting times equal to or less than the correction end count. The imaging device according to any one of 1 to 6. In a control method of an imaging apparatus comprising: an imaging element; a diaphragm unit that changes an amount of a light beam that reaches the image sensor; and a shutter unit that blocks a light beam that reaches the image sensor.
A control method for an imaging apparatus, comprising: a correction step of correcting a deviation of an aperture value of the aperture means that changes in accordance with the number of times the shutter means is continuously driven.

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