JP2001324736A - Photographing device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photographing device and a control method therefor for obtaining a good picture and also effectually realizing miniaturizing, a low cost, or the like. SOLUTION: A picture photographed by a photographing means 14 is recorded by a recording means 30, and the recorded picture is displayed by a display means 28. This photographing device has at least, one aperture with a filter and one aperture without a filter, respectively, and when these plural apertures are varied, focus correction values by the varied filters are calculated, and the focus is controlled at the corrected focus position at the time of the next focus control. The filters are ND filters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for picking up, recording or reproducing a still image or a moving image and a control method therefor.

[0002]

2. Description of the Related Art Conventionally, in an image pickup apparatus such as a digital camera, when a subject is bright, an image is taken with a reduced exposure amount by increasing a shutter speed or reducing an aperture diameter. However, in a digital camera, the number of pixels of an image sensor increases year by year, and at the same time, the pixel pitch per pixel decreases. Accordingly, the influence of diffraction when the aperture diameter is reduced increases, and it is difficult to reduce the aperture diameter in order to obtain a good image as it is.

[0003]

However, when the subject is bright, the amount of exposure must be reduced. If the aperture diameter cannot be reduced, there is a method of increasing the shutter speed. However, such a high-speed shutter hinders downsizing, cost reduction, and the like of the camera.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image pickup apparatus capable of obtaining a good image, effectively realizing a reduction in size and cost, and a control method thereof.

[0005]

An image pickup apparatus according to the present invention is an image pickup apparatus in which an image picked up by an image pickup means is recorded by a recording means, and the recorded image can be displayed by a display means. It has one or more apertures with and without apertures, and when changing a plurality of apertures, calculates a focus correction amount by a filter of the changed apertures and calculates the corrected focus at the next focus control. The position is controlled.

Further, in the imaging apparatus according to the present invention, the filter is an ND filter. Further, in the imaging apparatus according to the present invention, the change of the aperture is performed after photometry. Further, in the imaging apparatus according to the present invention, the change of the aperture is performed before flash photographing, and then focus control is performed. Further, in the imaging apparatus according to the present invention, the aperture is changed after a zoom is changed, and then focus control is performed. In the imaging apparatus according to the present invention, the focus control is performed after distance measurement.

[0007] A control method of an image pickup apparatus according to the present invention is a control method of an image pickup apparatus, wherein an image picked up by an image pickup means is recorded by a recording means, and the recorded image can be displayed by a display means. When changing a plurality of apertures each including one or more apertures with and without a filter, a focus correction amount by the filter of the changed aperture is calculated, and the focus is adjusted to the corrected focus position at the next focus control. It is characterized by the following.

Further, in the control method of the image pickup apparatus according to the present invention, the change of the aperture is performed after photometry.
Further, in the control method of the image pickup apparatus according to the present invention, the change of the aperture is performed before flash photographing, and then focus control is performed. Further, in the control method of the image pickup apparatus according to the present invention, the change of the aperture is performed after a zoom is changed, and then focus control is performed. In the method of controlling an imaging device according to the present invention, the focus control is performed after distance measurement.

Further, a recording medium of the present invention is a computer-readable recording medium storing a program for causing a computer to function as any one of the above means. Further, a recording medium of the present invention is a computer-readable recording medium storing a program for executing any of the above-described processing procedures.

According to the present invention, a plurality of apertures with an ND filter are prepared in addition to the open aperture. As a result, even for a bright subject, a good image with little influence of diffraction can be obtained without requiring a high-speed shutter, and the camera can be reduced in size and cost.

In addition, when the ND filter enters or exits the optical path, and when there are a plurality of ND filters having different thicknesses and materials, the focus position needs to be corrected. In this case, the correction amount is calculated when the aperture is changed, and the position is corrected to the position corrected at the next focus control.
Focus correction can be performed without increasing the number of times of control compared to the related art.

[0012]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a configuration according to an embodiment of the present invention. In the figure, reference numeral 100 denotes an image processing device. Reference numeral 10 denotes a photographing lens, 12 denotes a shutter having an aperture function, and 14 denotes an image sensor that converts an optical image into an electric signal. The sensitivity of the image sensor can be changed by control of a system control circuit 50. 16 is an image sensor 14
A / D converter for converting the analog signal output of the A / D converter into a digital signal. Reference numeral 18 denotes an image sensor 14, an A / D converter 16, a D / A
This is a timing generation circuit that supplies a clock signal and a control signal to the converter 26, and is controlled by the memory control circuit 22 and the system control circuit 50.

Reference numeral 20 denotes an image processing circuit which performs predetermined pixel interpolation processing and color conversion processing on data from the A / D converter 16 or data from the memory control circuit 22.
In the image processing circuit 20, predetermined arithmetic processing is performed using the captured image data, and the system control circuit 50 controls the exposure control means 40 and the distance measurement control means 42 based on the obtained arithmetic result. , TTL (through the lens) type AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash pre-emission) processing. Further, the image processing circuit 20 performs predetermined arithmetic processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained arithmetic result.

Reference numeral 22 denotes a memory control circuit, which includes an A / D converter 16, a timing generation circuit 18, an image processing circuit 20,
Image display memory 24, D / A converter 26, memory 30,
The compression / decompression circuit 32 is controlled. The data of the A / D converter 16 is written to the image display memory 24 or the memory 30 via the image processing circuit 20 and the memory control circuit 22 or directly via the memory control circuit 22.

Reference numeral 24 denotes an image display memory; 26, a D / A converter; and 28, an image display unit comprising a TFT LCD or the like.
The display image data written in the image display memory 24 is displayed by the image display unit 28 via the D / A converter 26. If the captured image data is sequentially displayed using the image display unit 28, an electronic finder function can be realized.

The display of the image display unit 28 can be arbitrarily turned ON / OFF in accordance with an instruction from the system control circuit 50. When the display is turned off, the power consumption of the image processing apparatus 100 can be significantly reduced.

Reference numeral 30 denotes a memory for storing photographed still images and moving images, which has a sufficient storage capacity for storing a predetermined number of still images and moving images for a predetermined time. Accordingly, even in the case of continuous shooting or panoramic shooting in which a plurality of still images are continuously shot, it is possible to write a large amount of images to the memory 30 at high speed. The memory 30 can also be used as a work area for the system control circuit 50. Reference numeral 32 denotes a compression / decompression circuit for compressing / decompressing image data by adaptive discrete cosine transform (ADCT) or the like. Write 30.

Reference numeral 40 denotes an exposure control means for controlling the shutter 12 having an aperture function, and also has a flash dimming function in cooperation with the flash 48.

Reference numeral 42 denotes a distance measuring control unit that controls focusing of the photographing lens 10, 44 denotes a zoom control unit that controls zooming of the photographing lens 10, and 46 controls the operation of an optical image stabilizing unit 102 that is a unit that corrects shake. Anti-vibration control means. The anti-vibration control unit 46 has a normal mode in which power consumption is large but tracking characteristics are good, and an economy mode in which power consumption is small but tracking characteristics are slightly inferior. 4
Reference numeral 8 denotes a flash, which also has an AF auxiliary light projecting function and a flash light control function. The exposure control means 40 and the distance measurement control means 42 are controlled using the TTL method, and the system control circuit 50 controls the exposure control means 40 and the distance measurement based on the calculation result obtained by calculating the captured image data by the image processing circuit 20. The control unit 42 is controlled.

Reference numeral 50 denotes a system control circuit for controlling the entire image processing apparatus 100, and reference numeral 52 denotes a memory for storing constants, variables, programs, and the like for operating the system control circuit 50. Reference numeral 54 denotes a display unit such as a liquid crystal display device or a speaker that displays an operating state or a message using characters, images, sounds, or the like in response to execution of a program in the system control circuit 50. One or a plurality of them are installed at positions near the part where they are easily visible, and are configured by a combination of, for example, LCDs, LEDs, sound-generating elements, and the like. The display unit 54 has a part of its functions installed in the optical viewfinder 104.

Among the display contents of the display unit 54, those displayed on the LCD and the like include a single shot / continuous shooting display, a self-timer display, a compression ratio display, a recording pixel number display, a recording number display, and a remaining number of recordable images. Display, shutter speed display, aperture value display, exposure compensation display, flash display, red-eye reduction display, macro shooting display, buzzer setting display,
Clock battery level display, battery level display, error display, information display using multiple digits, recording media 200 and 210
Display, communication I / F operation display, date / time display, and the like.

Among the display contents of the display unit 54, those displayed in the optical viewfinder 104 include a focus display, a camera shake warning display, a flash charge display, a shutter speed display, an aperture value display, and an exposure correction display. is there.

Reference numeral 56 denotes an electrically erasable and recordable nonvolatile memory, for example, an EEPROM or the like.

60, 62, 64, 66, 68 and 70
Is an operation means for inputting various operation instructions of the system control circuit 50, and is composed of one or a combination of a switch, a dial, a touch panel, pointing by gaze detection, a voice recognition device, and the like.

Here, these operation means will be specifically described. Reference numeral 60 denotes a mode dial switch, which includes a power-off mode, an automatic shooting mode, a shooting mode, a panorama splicing shooting mode, a playback mode, a multi-screen playback / erase mode,
Each function mode such as a PC connection mode can be switched and set. Reference numeral 62 denotes a shutter switch SW1, which is turned on during the operation of a shutter button (not shown).
An instruction is issued to start operations such as AF (auto focus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, and EF (flash pre-flash) processing.

Reference numeral 64 denotes a shutter switch SW2,
Turns ON when the shutter button (not shown) is completed,
A signal read from the image sensor 12 is converted into an A / D converter 16,
Exposure processing for writing image data to the memory 30 via the memory control circuit 22 and development processing using calculations in the image processing circuit 20 and the memory control circuit 22 are performed, and the image data is read from the memory 30. Then, the compression / expansion circuit 32 performs compression, and instructs to start the operation of a series of processes of a recording process of writing image data to the recording medium 200 or 210.

An image display ON / OFF switch 66 can set ON / OFF of the image display unit 28. With this function, when photographing is performed using the optical viewfinder 104, the image display unit 28 such as a TFT LCD is used.
By cutting off the current supply to the power, power can be saved. Reference numeral 68 denotes a zoom switch which can switch between enlargement and reduction of the recorded image.

An operation unit 70 includes various buttons, a touch panel, etc., and includes a menu button, a set button, a macro / non-macro switching button, a multi-screen playback change button, a flash setting button, and a single / continuous / self-timer switching. Button, menu move "+" (plus) button, menu move "-" (minus) button, play image move "+" (plus) button, play image move "-" (minus) button, shooting image quality selection button, exposure There are a correction button, a date / time setting button, and the like.

Reference numeral 80 denotes a power supply control means, which comprises a battery detection circuit, a DC-DC converter, a switch circuit for switching a block to be energized, and the like, and detects whether or not a battery is installed, the type of battery, and the remaining battery level. Based on the detection result and the instruction of the system control circuit 50.
The C converter is controlled to supply a necessary voltage to each unit including the recording medium for a necessary period. Reference numeral 82 denotes a connector, 84 denotes a connector, and 86 denotes a power supply unit including a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, and an AC adapter.

Reference numerals 90 and 94 denote interfaces with recording media such as a memory card and a hard disk.
Reference numeral 6 denotes a connector for connecting to a recording medium such as a memory card or a hard disk. Reference numeral 98 denotes a recording medium attachment / detachment detecting unit for detecting whether or not the recording medium 200 or 210 is attached to the connector 92 and / or 96.

In this embodiment, the description has been made assuming that there are two interfaces and a connector for attaching a recording medium. Of course, the interface and the connector for attaching the recording medium may have a single or plural number of systems. Further, a configuration may be adopted in which interfaces and connectors of different standards are combined.

The interface and the connector may be configured using a standard such as a PCMCIA card or a CF (Compact Flash (registered trademark)) card. Further, when the interfaces 90 and 94 and the connectors 92 and 96 are configured using a standard such as a PCMCIA card or a CF (Compact Flash) card, a LAN card, a modem card, a USB card, an IEEE 1394 card,
By connecting various communication cards such as P1284 card, SCSI card, PHS and other communication cards, image data and management information attached to the image data can be transferred between other computers and peripheral devices such as printers. Can be.

Reference numeral 102 denotes an optical image stabilizing unit for preventing image shake, which is controlled by an image stabilizing control unit 46. 10
Reference numeral 4 denotes an optical finder, which can perform photographing using only the optical finder without using the electronic finder function of the image display unit 28. In the optical viewfinder 104, some functions of the display unit 54, such as a focus display, a camera shake warning display, a flash charge display,
A shutter speed display, an aperture value display, an exposure compensation display, and the like are provided. 110 is a communication means, RS2
32C, USB, IEEE1394, P1284, SC
It has various communication functions such as SI, modem, LAN, and wireless communication. Reference numeral 112 denotes the image processing apparatus 10
0 is a connector for connecting to another device or an antenna in the case of wireless communication.

Reference numeral 200 denotes a recording medium such as a memory card or a hard disk. The recording medium 200 includes a recording unit 202 including a semiconductor memory or a magnetic disk, an interface 204 with the image processing apparatus 100, and a connector 206 for connecting to the image processing apparatus 100. 2
Reference numeral 10 denotes a recording medium such as a memory card or a hard disk. The recording medium 210 includes a recording unit 212 including a semiconductor memory or a magnetic disk, an interface 214 with the image processing apparatus 100, and a connector 216 for connecting to the image processing apparatus 100.

Referring to FIG. 2, the operation of the image processing apparatus 100 according to this embodiment will be described. FIG. 2 shows a flowchart of a main routine of the image processing apparatus 100 according to the present embodiment. In step S101, the system control circuit 50
Accordingly, if the shutter switch SW1 (62) has been pressed, the process proceeds to step S102, and if not, the process returns to step S101.

In step S102, a photographing preparation operation such as photometry and colorimetry is performed, and the flow advances to step S103. If the result of the photometry in step S102 in step S103 indicates that the subject is Ev11 or less, step S104
To step S106 if it is Ev13 or higher.
Then, in cases other than the above, that is, in the case of Ev11 to 13, the process proceeds to step S105.

In step S104, the aperture is opened.
The value is controlled to Av3, and the process proceeds to step S107. In step S105, the aperture is controlled to Av5, and the process proceeds to step S108. Here, the “aperture of Av5” is an aperture having an aperture diameter of Av4 and a one-stage ND filter attached thereto. In step S106, the aperture is controlled to Av7, and the flow advances to step S109. Here, the “aperture of Av7” is an aperture having an aperture diameter of Av4 and a three-stage ND filter attached thereto. In the present invention, a plurality of apertures can be changed by using a plurality of ND filters as described above.

In step S107, a correction value when no ND filter is provided is calculated, and the flow advances to step S110. In step S108, a correction value for one stage of the ND filter is calculated, and the process proceeds to step S110. In step S109, a correction value for the case of three ND filters is calculated, and the process proceeds to step S110.

In step S110, a distance measuring operation is performed based on the correction value, a focusing operation is performed based on the distance measurement result, and the flow advances to step S111. Step S11
In step 1, if the shutter switch SW2 (64) has been pressed, the process proceeds to step S113; otherwise, the process proceeds to step S112. In step S112, if the shutter switch SW1 (62) has been pressed, the process proceeds to step S111; otherwise, the process returns to step S101.

In step S113, step S10
From the photometry result in 2, if the subject is dark and a flash is required, the process proceeds to step S114, otherwise, the process proceeds to step S115. If it is determined in step S114 that the subject distance is equal to or more than 2 m from the distance measurement result in step S110, the process proceeds to step S117, where the distance of the subject is 1 m.
In the following cases, the process proceeds to step S119. In cases other than the above, that is, when the subject distance is 1 to 2 m, step S118.
Proceed to.

In step S117, the aperture is opened.
The value is controlled to Av3, and the process proceeds to step S120. In step S118, the aperture is controlled to Av5, and
Go to 121. Here, the “aperture of Av5” is an aperture having an aperture diameter of Av4 and a one-stage ND filter attached thereto. In step S119, the aperture is controlled to Av7, and the flow advances to step S122. Here, the “aperture of Av7” is an aperture having an aperture diameter of Av4 and a three-stage ND filter attached thereto.

In step S120, a correction value when no ND filter is provided is calculated, and the flow advances to step S123. In step S121, a correction value for one stage of the ND filter is calculated, and the process proceeds to step S123. In step S122, a correction value in the case of three ND filters is calculated, and the process proceeds to step S123. Step S123
In step, a focusing operation is performed based on the correction value, and the process proceeds to step S115.

Then, photographing is performed in step S115, and the flow advances to step S116. The image captured in step S116 is recorded, and the process returns to step S111.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows an image processing apparatus 1 according to the present embodiment.
The flowchart of the main routine of 00 is shown. Step S
If the image display ON / OFF switch 66 is turned ON by the system control circuit 50 in 201, the process proceeds to step S202, otherwise, the process returns to step S201.

In step S202, image display preparation operations such as photometry and colorimetry are performed, and the flow advances to step S203.
In step S203, if the result of the photometry in step S202 indicates that the subject is Ev11 or less, step S20
The process proceeds to step S206 in the case of Ev13 or more, and proceeds to step S206 in cases other than the above, that is, in the case of Ev11 to E13.

In step S204, the aperture is opened.
The value is controlled to Av3, and the process proceeds to step S207. In step S205, the aperture is controlled to Av5, and the flow advances to step S208. Here, the “aperture of Av5” is an aperture having an aperture diameter of Av4 and a one-stage ND filter attached thereto. In step S206, the aperture is controlled to Av7, and the flow advances to step S209. Here, the “aperture of Av7” is an aperture having an aperture diameter of Av4 and a three-stage ND filter attached thereto.

In step S207, a correction value when no ND filter is provided is calculated, and the flow advances to step S210. In step S208, a correction value for one stage of the ND filter is calculated, and the process proceeds to step S210. In step S209, a correction value for three stages of the ND filter is calculated, and the process proceeds to step S210.

In step S210, a focusing operation is performed based on the correction value, and an image is displayed.
Proceed to 11. In step S211, image display ON /
If the OFF switch 66 is ON, step S
The process proceeds to step S213, otherwise proceeds to step S212. In step S212, the image display ends, and the process returns to step S201.

In step S213, photometry and colorimetry are performed, and the flow advances to step S214. If the zoom switch 68 is ON in step S214, the process proceeds to step S215; otherwise, the process proceeds to step S21.
Return to 1. A zoom operation is performed in step S215, and the process proceeds to step S216. If the zoom switch 68 is turned off in step S216, the process proceeds to step S216.
The process proceeds to 217, and otherwise returns to step S216. The image captured in step S217 is recorded, and the process returns to step S202.

Here, each functional block and processing procedure shown in the above various embodiments may be constituted by hardware, or may be constituted by CPU or MPU, ROM and ROM.
It may be constituted by a microcomputer system composed of an AM or the like, and its operation may be realized according to a work program stored in a ROM or a RAM. The present invention also includes a software program for realizing the functions described above, which is provided to a RAM so as to realize the functions of the respective functional blocks, and which is executed by operating the functional blocks according to the programs. include.

In this case, the software program itself realizes the functions of the above-described embodiments, and the program itself and means for supplying the program to a computer, for example, a recording medium storing the program Constitute the present invention. As a storage medium for storing such a program, the above-described ROM or RAM
Besides, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-RO
M, CD-I, CD-R, CD-RW, DVD, zi
p, a magnetic tape, a nonvolatile memory card, or the like can be used.

When the computer executes the supplied program, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software running on the computer. Needless to say, such a program is also included in the embodiment of the present invention when the functions of the above-described embodiment are realized in cooperation with the above.

Further, after the supplied program is stored in the memory provided on the function expansion board of the computer or the function expansion unit connected to the computer, the program is provided on the function expansion board or the function expansion unit based on the instruction of the program. It is needless to say that the present invention also includes a case where the CPU or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0054]

As described above, according to the present invention, in addition to the open aperture, a plurality of apertures with an ND filter are prepared, and when the aperture is changed, the correction amount of the focus position is calculated.
By controlling to the position corrected at the time of the next focus control, focus correction can be performed without increasing the number of times of control as compared with the related art. This makes it possible to obtain a good image that is economical and has a small influence of diffraction without requiring a high-speed shutter even for a bright subject, and has advantages such as effective realization of a compact camera and low cost. are doing.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a part of a main routine in the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a part of a main routine according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 photographing lens 12 shutter 14 image sensor 16 A / D converter 18 timing generation circuit 20 image processing circuit 22 memory control circuit 24 image display memory 26 D / A converter 28 image display unit 30 memory 32 image compression / decompression circuit 40 exposure Control means 42 Distance measurement control means 44 Zoom control means 46 Image stabilization control means 48 Flash 50 System control circuit 52 Memory 54 Display unit 56 Non-volatile memory 60 Mode dial switch 62 Shutter switch SW1 64 Shutter switch SW2 66 Image display ON / OFF switch 68 Zoom switch 70 Operation unit 80 Power control means 82 Connector 84 Connector 86 Power supply means 90 Interface 92 Connector 94 Interface 96 Connector 98 Recording medium attachment / detachment detection means 100 Image Processing device 102 Optical anti-vibration means 104 Optical finder 110 Communication means 112 Connector (or antenna) 200 Recording medium 202 Recording unit 204 Interface 206 Connector 210 Recording medium 212 Recording unit 214 Interface 216 Connector

Claims (13)

[Claims] 1. An image pickup apparatus in which an image picked up by an image pickup means is recorded by a recording means, and the recorded image can be displayed by a display means, wherein an iris with a filter and an iris without a filter are respectively provided. An imaging apparatus having at least one aperture, wherein when the plurality of apertures are changed, a focus correction amount by a filter of the changed aperture is calculated, and the focus is controlled to the corrected focus position at the next focus control. . 2. The imaging device according to claim 1, wherein the filter is an ND filter. 3. The imaging apparatus according to claim 1, wherein the change of the aperture is performed after photometry. 4. The imaging apparatus according to claim 1, wherein the change of the aperture is performed before flash photographing, and then focus control is performed. 5. The imaging apparatus according to claim 1, wherein the change of the aperture is performed after the zoom is changed, and then the focus control is performed. 6. The imaging apparatus according to claim 1, wherein the focus control is performed after distance measurement. 7. A control method of an image pickup apparatus, wherein an image picked up by an image pickup means is recorded by a recording means, and the recorded image can be displayed by a display means, wherein a diaphragm provided with a filter is not provided. A method of controlling an imaging apparatus, comprising: calculating a focus correction amount by a filter of a changed aperture when changing a plurality of apertures each including one or more apertures, and controlling a focus position corrected at a next focus control. . 8. The method according to claim 7, wherein the change of the aperture is performed after photometry. 9. The method according to claim 7, wherein the change of the aperture is performed before flash photographing, and then focus control is performed. 10. The method according to claim 7, wherein the change of the aperture is performed after the zoom is changed, and then the focus control is performed. 11. The method according to claim 7, wherein the focus control is performed after distance measurement. 12. A computer-readable recording medium storing a program for causing a computer to function as each of the means according to claim 1. Description: 13. A computer-readable recording medium storing a program for executing the processing procedure of the method according to claim 7. Description: