JP2000358189A - Imaging device and control method thereof - Google Patents

Abstract

(57) [Problem] To provide an imaging device capable of performing exposure correction according to a user's intention. SOLUTION: A predetermined arithmetic processing is performed using image signal data from an image pickup device 14, and the amount of incident light is controlled by controlling a shutter 12 by an exposure control means 42 with an obtained control value, thereby obtaining an exposure correction amount. When the exposure correction amount is set by the setting unit 71, the calculated control value is corrected based on the set exposure correction amount. Then, exposure control at the time of main exposure is performed using the corrected control value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image pickup apparatus for picking up a still image or a moving image and a control method therefor.

[0002]

2. Description of the Related Art Conventionally, an image processing apparatus such as an electronic camera for capturing, recording, and reproducing still images and moving images using a memory card having a solid-state memory element as a storage medium is already commercially available. Electronic cameras equipped with an electronic finder are also on sale.

[0003] These electronic cameras have a function of continuously displaying images before photographing, allowing the user of the electronic camera to determine the composition, and reproducing the photographed images immediately after photographing.
The convenience is high and it is beneficial for the user of the electronic camera.

In the above-mentioned electronic cameras, the manual setting of the exposure correction amount is mainly used. Exposure correction in a conventional image processing device such as an electronic camera is performed in an exposure control loop that follows subject brightness to an appropriate level.

[0005]

However, when the luminance signal obtained by performing the exposure correction of, for example, + x steps exceeds the full range of the A / D converter by using the above-described conventional exposure correction method, A high-luminance signal exceeding the full range is not digitized due to overflow. In the exposure control loop, the average value of the A / D converter output of the luminance signal subjected to the exposure correction of + x stage is x times the average value of the A / D converter output of the initially set luminance signal (appropriate exposure level). Until the exposure control is performed to increase the exposure level for the signal not reaching the full range.

As a result, although the operator has set the + x-step correction, the operator recognizes that excessive correction has been performed, and exposure correction is contrary to the operator's intention. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide an imaging apparatus capable of performing exposure correction according to a user's intention and a control method thereof. And

[0008]

An image pickup apparatus and a control method thereof according to the present invention are configured as follows.

(1) In an image pickup apparatus, an image pickup optical system including light amount adjusting means for adjusting the amount of light incident on the image pickup device, and photometry for measuring the amount of light incident on the image pickup device via the image pickup optical system. Means, an exposure control means for controlling the amount of incident light by controlling the light amount adjusting means based on the measurement result, and an exposure correction amount setting means for setting an exposure correction amount. When the exposure correction amount is set, the control value of the exposure control means calculated based on the measurement result is corrected based on the exposure correction amount set by the exposure correction amount setting means.

(2) In the imaging device of (1), the exposure control means can change the control value regardless of the measurement result.

(3) In the image pickup apparatus of (1) or (2), the light quantity adjusting means is a light quantity adjusting aperture, and the exposure control means controls the aperture of the light quantity adjusting aperture.

(4) In any one of the imaging devices (1) to (3), the photometric means is an imaging device.

(5) In any one of the imaging devices (1) to (4), the control value is a value for controlling the accumulation time of the imaging device.

(6) In the control method of the image pickup apparatus, the amount of light incident on the image pickup device is measured by a photometric unit via an image pickup optical system including a light amount adjustment unit for adjusting the amount of light incident on the image pickup device. If the exposure correction amount is set by the exposure correction amount setting unit that controls the light amount adjustment unit based on the measurement result and controls the incident light amount by the exposure control unit and sets the exposure correction amount, the measurement result The control value of the exposure control means calculated based on the exposure correction amount is corrected based on the exposure correction amount set by the exposure correction amount setting means.

(7) In the control method of the image pickup apparatus of (6), the exposure control means can change the control value regardless of the measurement result.

(8) In the control method of the image pickup apparatus according to (6) or (7), the light quantity adjusting means is a light quantity adjusting aperture, and the exposure control means controls the aperture of the light quantity adjusting aperture. .

(9) In the control method of any one of the above (6) to (8), the photometric means is an image sensor, and the amount of incident light is measured by the image sensor.

(10) In the control method of any one of the above (6) to (9), the control value is a value for controlling the accumulation time of the image pickup device, and the exposure control means stores the accumulation time of the image pickup device. Controlled time.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the image pickup apparatus according to the present embodiment.

In FIG. 1, reference numeral 100 denotes an image processing apparatus. 10 is a variable power lens group, 11 is a focusing lens group, 1
Reference numeral 2 denotes a shutter (a light amount adjusting unit) having an aperture function for adjusting the amount of incident light, 14 an image sensor for converting an optical image into an electric signal, and 15 an image sensing sensitivity adjusting unit for setting the sensitivity of the image sensor 14. In the embodiment, a gain amplifier that can be linearly varied from 0 to 24 dB is employed.

Reference numeral 16 denotes an A / D converter for converting an analog signal output of the image sensor 14 into a digital signal. Reference numeral 18 denotes a clock signal and a control signal to the image sensor 14, the A / D converter 16, and the D / A converter 26. This is a timing generation circuit for supplying, and is controlled by the memory control circuit 22 and the system control circuit 50.

The magnification of the variable magnification lens group 10 is Wid.
A configuration is adopted in which the distance from the e (wide) end to the Tele (tele) end is divided into eight, and zooming of nine positions is possible, including the Wide end and the Tele end.

An image processing circuit 20 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.

Further, in the image processing circuit 20, predetermined arithmetic processing is performed using the captured image data, and the system control circuit 50 controls the automatic exposure control means 40 and the distance measurement control means 42 based on the obtained arithmetic result. Control the
TTL (through-the-lens) type AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash pre-emission) processing are performed.

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 transmitted through the image processing circuit 20 and the memory control circuit 22 or the data of the A / D converter 16 is transmitted directly through the memory control circuit 22 to the image display memory 24 or the memory. 30 is written.

Reference numeral 24 denotes an image display memory; 26, a D / A converter; and 28, an image display unit comprising a liquid crystal display, such as a TFT LCD. Image data for display written in the image display memory 24 is D / A. The image is displayed by the image display unit 28 via the A converter 26.

If the image data picked up by the image display unit 28 is sequentially displayed, an electronic finder function can be realized.

The image display unit 28 can arbitrarily turn on / off the display 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 is greatly reduced. Can be reduced.

Reference numeral 30 denotes a memory for storing the photographed still images and moving images, which has a sufficient storage capacity to store a predetermined number of stop images and moving images for a predetermined time.

Thus, 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 is provided with a system control circuit 50.
Can also be used as a work area.

32 is an adaptive discrete cosine transform (ADCT)
A compression / decompression circuit for compressing / decompressing image data by, for example, reading an image stored in the memory 30 and performing compression or decompression processing, and storing the processed data in the memory 3
Write to 0.

Reference numeral 40 denotes a shutter 12 having an aperture function,
Electronic shutter control means for controlling the accumulation time from the charge discharging operation of the image sensor 14 to the readout operation by the timing generation circuit 18 and exposure control means for controlling the imaging sensitivity adjustment means 15. It also has a dimming function.

Reference numeral 42 denotes a distance measurement control unit that controls focusing of the focusing system lens 11, 44 denotes a zoom control unit that controls zooming of the variable magnification system lens 10, and 46 denotes a barrier that controls the operation of the protection unit 102 which is a barrier. Control means.

Reference numeral 48 denotes a flash, which also has a function of projecting AF auxiliary light and a function of controlling flash light.

The automatic exposure (exposure) control means 40 and the distance measurement control means 42 are controlled by using the TTL method, and the system control circuit 50 The automatic exposure control means 40 and the distance measurement control means 42 are controlled. The details of the automatic exposure control means 40 will be described later.

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 or a speaker for displaying an operation state or a message using characters, images, sounds, or the like in accordance with the execution of the program by the system control circuit 50. A single or a plurality of units are installed at easily visible positions near the 100 operation units, 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.

Of the display contents of the display unit 54, those displayed on the LCD or the like include a single shot / continuous shooting display, a long time shooting display, a night view shooting display, a self-timer display, a compression ratio display, and the number of recorded pixels. Display, number of recorded images, remaining shots, shutter speed, aperture, exposure compensation, flash, red-eye reduction,
Elapsed time display (from red-eye reduction lamp lighting, previous shooting), macro shooting display, buzzer setting display, battery remaining battery display, battery remaining display, error display, multi-digit information display, recording medium 200 And display of the attachment / detachment state of the recording medium 210, communication I / F (interface) operation display, date / time display, and the like.

Of the display contents of the display section 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, an exposure correction display, and the like. There is.

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

Reference numerals 60, 62, 64, 66, 68, 70, and 71 denote operating means for inputting various operation instructions of the system control circuit 50, such as switches, dials, touch panels, pointing by gaze detection, and voice recognition. It is composed of a single device or a combination of multiple devices.

Here, these operation means will be specifically described.

Reference numeral 60 denotes a mode dial switch, which can switch and set various function modes such as power-off, automatic photographing mode, photographing mode, panoramic photographing mode, reproducing mode, multi-screen reproducing / erasing mode, and PC connection mode.

Reference numeral 62 denotes a shutter switch (SW1).
Turns on during the operation of the shutter button (not shown), and A
F (auto focus) processing, AE (auto exposure) processing,
An instruction is issued to start operations such as AWB (auto white balance) processing and EF (flash pre-emission) processing.

Reference numeral 64 denotes a shutter switch (SW2).
The shutter button (not shown) is turned on when the operation is completed, and the signal read from the image sensor 14 is written to the memory 30 via the A / D converter 16 and the memory control circuit 22 in an exposure process. Control circuit 2
2 starts the operation of a series of processing of developing processing using the calculation in step 2, reading image data from the memory 30, compressing the image data in the compression / decompression circuit 32, and writing the image data in the recording medium 200 or 210. To instruct.

Reference numeral 66 denotes an image display ON / OFF switch.
ON / OFF of the image display unit 28 can be set. With this function, it is possible to save power by cutting off the current supply to an image display unit such as a TFT LCD when taking a picture using the optical viewfinder 104.

Reference numeral 68 denotes a quick review ON / OFF switch for setting a quick review function for automatically reproducing image data taken immediately after shooting. In this embodiment, particularly, the setting of the quick review function when the image display unit 28 is turned off is provided.

Reference numerals 67 and 69 denote variable power lens groups 10 respectively.
Tele switch (SW) for instructing the driving direction of
This is a Wide switch (SW). The Tele switch and the Wide switch are configured so that only one of the switches is mechanically turned on.

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, multi-screen playback page break button, flash setting button, single shot / continuous shooting / self-timer / long time (slow shutter) / night scene shooting mode switching button, menu move + (plus) button, menu move- There are a (minus) button, a play image move + (plus) button, a play image-(minus) button, a shooting image quality selection button, a date / time setting button, and the like.

There is an exposure correction amount setting means 71 for exposure correction. When the camera user sets and inputs the exposure correction amount to 71, the 71 inputs the exposure correction amount to the system control circuit 50.

Reference numeral 80 denotes a power supply control means, a battery detection circuit, D
It comprises a C-DC converter, a switch circuit for switching a block to be energized, and the like, and detects the presence or absence of a battery, the type of battery, the remaining battery level, and performs DC based on the detection result and an instruction from the system control circuit 50. Control the DC converter to supply a required voltage to each unit including the recording medium for a required period.

Reference numeral 82 denotes a connector, 84 denotes a connector, and 86 denotes a power supply means 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 an interface (I / F) with a recording medium such as a memory card or a hard disk;
2 and 96 are connectors for connecting to a recording medium such as a memory card or a hard disk, and 98 is a connector 92 and / or a recording medium 200 or a recording medium 210 to the connector 96.
Is a recording medium attachment / detachment detection unit for detecting whether or not the recording medium is attached.

In this embodiment, the description has been made assuming that there are two interfaces and connectors 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. In addition, a configuration may be adopted in which interfaces and connectors of different standards are provided in combination.

As the interface and the connector,
It may be configured using a card conforming to a standard such as a PCMCIA card or a CF (compact flash) card.

Further, the interface 90 and the interface 94, and the connector 92 and the connector 96
PCMCIA card or CF (Compact Flash)
When using a card that conforms to the standards of the card, etc.,
LAN card, modem card, USB card, IEEE
1394 card, P1284 card, SCSI card,
By connecting various communication cards such as a communication card such as a PHS, image data and management information attached to the image data can be transferred between other computers and peripheral devices such as a printer.

Reference numeral 102 denotes a protection unit which is a barrier that covers the imaging unit including the variable power lens 10 and the focusing lens 11 of the image processing apparatus 100 to prevent the imaging unit from being stained or damaged.

Reference numeral 104 denotes an optical finder, which enables 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, for example, a focus display, a camera shake warning display, a flash charge display, a shutter speed display,
An aperture value display, an exposure compensation display, a macro shooting setting display, and the like are provided.

Reference numeral 110 denotes communication means such as RS232C or US
It has various communication functions such as B, IEEE1394, P1284, SCSI, modem, LAN, wireless communication, and the like.

Reference numeral 112 denotes a connector for connecting the image processing apparatus 100 to another device by the communication unit 110 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 and a magnetic disk, an interface 204 with the image processing apparatus 100, and a connector 206 for connecting to the image processing apparatus 100.

Reference numeral 210 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 device 100, and a connector 216 for connecting to the image processing device 100.

In the above configuration, the image pickup device 14 constitutes a photometric means for measuring the amount of incident light.

The operation of the image pickup apparatus according to the first embodiment will be described below with reference to FIGS. 1, 2 and 3.

FIG. 2 is a flowchart showing a control operation in a main routine of the image pickup apparatus (image processing apparatus 100) according to the first embodiment, which will be described with reference to FIG.

When the mode dial 60 is turned from the power-off state to the power-on state (imaging mode), the system control circuit 50 detects the mode dial state (step S102).

Next, when the shutter switch (SW1) 62 is pressed (step S103), the system control circuit 5
0 activates the image pickup means (step S104), performs predetermined calculation processing using the image signal data from the image pickup device 14, and performs distance measurement processing on the distance measurement control means 42 based on the obtained calculation result. Then, the focus of the focusing system lens 11 is adjusted to the subject, and AF control is performed (step S105).

Subsequently, the system control circuit 50 activates the exposure control means 40 to perform AE control so as to obtain an appropriate exposure (step S200). The details of the AE control will be described later. Next, the system control circuit 50 performs a predetermined calculation process using the image signal data from the image sensor 14, and uses the image processing circuit 20 until the obtained calculation result is determined to be appropriate as the white balance. AWB (auto white balance) control is performed (step S10)
6).

Next, a shutter switch (SW2) 64
Is pressed (step S107), main exposure for photographing an image to be recorded is performed (step S108). The details of the main exposure will be described later. Finally, the recording medium 200 or the recording medium 21 such as a memory card or a compact flash card is connected via the interface 90 or the interface 94, the connector 92 or the connector 96.
0 is written (step S10).
9). If the shutter switch (SW2) 64 is not pressed, the process waits until the switch (SW2) 64 is pressed.

Next, the AE control will be described with reference to FIGS. FIG. 3 is a flowchart showing the exposure control operation of step S200 in FIG.

The system control circuit 50 controls the exposure control means 4
0 (step S201), and the activated exposure control means 40 sets the appropriate exposure flag to 0 (step S2).
02). The proper exposure flag is used to set a bit to 1 when the exposure is proper, and to set the bit to 0 when the exposure is not proper. Subsequently, an initial setting of the photometry means such as a photometry area setting required for photometry is performed (step S203). Next, the system control circuit 50 activates the exposure control calculation means, initializes the subject brightness (Bv) value and the imaging sensitivity (Sv) value (step S204), and the exposure control value calculation means sets the aperture control (Av). The value and the electronic shutter control (Tv) value are analyzed and calculated (step S205), and the aperture means (step S2)
06), the shutter 12 which is an electronic shutter means (step S207) is controlled.

Although not shown, the exposure control calculating means is written in the program area of the system control circuit 50.

Subsequently, the system control circuit 50 reads out the signal (step S208) exposing the image pickup device 14 using the memory control 22 and the timing generator 18 (step S209), and the image processing circuit 20 reads out the signal. The luminance output Yout is derived from the signal via the A / D converter (step S210). Subsequently, the system control circuit 5
0 takes the ratio between the luminance output Yout from the image processing circuit and the target luminance level Yref, and derives the average (step S211).

Subsequently, the system control circuit 50 calculates the deviation amount (ΔBv) from the appropriate exposure level (step S 212) and the subject luminance (Bv) (step S 213) from the average of the above ratios of Yout and Yref. Derive.

After obtaining the subject brightness (Bv) and the ΔBv value, if the ΔBv value reaches an appropriate exposure level and falls within a preset error (± n) (step S214), the appropriate exposure flag is set to 1 (Step S215). ΔBv
If the value has not reached the appropriate exposure level (step S2
14) The Bv value is input to the exposure control value calculation means (step S205), and the operation of controlling the aperture means and the shutter 12, which is the electronic shutter means, to drive it into a predetermined range is repeated (steps S205 to S214).

After the exposure flag is set to 1 (step S215), the system control circuit 50 reads the exposure correction amount α set by the exposure correction amount setting means 71 and input to the system control circuit 50. Going (step S216),
Exposure correction is performed by adding or subtracting the exposure correction amount α to ΔBv (step S217), and a subject luminance (Bv) value is calculated (step S218).

Thus, the AE control ends (step S).
219).

Next, the main exposure will be described.

The main exposure is performed by the AE control so that the Av is adjusted appropriately to the Bv value obtained by adding or subtracting the finally determined correction amount.
This is performed using the v value and the Tv value (control value).

As a method of determining the Av value and the Tv value at the time of the main exposure, the following cases can be considered.

The Bv value before correction is corrected by changing only the Av value.

The Bv value before correction is corrected by changing only the Tv value.

For the Bv value before correction, the Av value, Tv
Change and correct each value.

As shown in FIG. 4, B at an appropriate exposure level
The average value of the A / D converter output of the luminance signal read out by the aperture control based on the values of v and Sv and the electronic shutter control is assumed to be c. Further, the average value of the output of the A / D converter of the luminance signal when the exposure correction of the + x stage is performed is set to d. If the luminance signal after performing the exposure correction of + x stage exceeds the full range of the A / D converter, the high-luminance signal exceeding the full range is not digitized by overflowing, and d = xc No. But,
As shown in FIG. 3, since the exposure correction is performed outside the exposure control loop, the exposure level of the signal not reaching the full range is not increased.

As a result, the operator recognizes that the + x-stage exposure correction has been performed, and the exposure correction is in accordance with the operator's intention.

Next, the operation of the image pickup apparatus according to the second embodiment will be described with reference to FIG. 1, FIG. 5, FIG. 6, FIG.

FIG. 5 is a flowchart of a control operation in a main routine of the imaging apparatus (image processing apparatus 100) according to the second embodiment, which will be described with reference to FIG.

When the mode dial 60 is turned from the power OFF state to the power ON state (imaging mode), the system control circuit 50 detects the mode dial state (step S302).

Next, when the image display switch 66 is turned on (step S303), the system control circuit 50
Starts the imaging means (step S303). If the image display switch 66 is in the OFF state (step S304), the switch (SW1) 62 in FIG. 2 described in the first embodiment waits for the ON state (step S103).
Then, the same operation as in the first embodiment is performed.

After the imaging means has been activated, the system control circuit 50 subsequently activates the exposure control means 40 and performs AE control 1 so as to obtain an appropriate exposure (step S400).
Details of the AE control 1 will be described later.

Next, the system control circuit 50 performs predetermined arithmetic processing using the image signal data from the image sensor 14, and controls the image processing circuit 20 until the obtained arithmetic result is determined to be appropriate as white balance. To perform AWB (auto white balance) control (step S30).
5).

Next, when the exposure correction amount setting means 71 is turned on (step S306), the system control circuit 50
Performs AE control 2 for exposure correction (step S5).
00). Details of the AE control 2 will be described later. At this time, the exposure correction amount can be set by displaying it on the image display unit 28 while operating the exposure correction amount setting means 71.

After the AE control 2 has been performed and the exposure correction amount setting means 71 is in the OFF state (step S30).
6), when the shutter switch (SW1) 62 is pressed (step S306), the system control circuit 50
An AE control 3 for canceling the exposure correction so that the exposure becomes appropriate for the control is performed (step S600). The details of the AE control 3 will be described later. Shutter switch (S
W1) If 62 is not pressed (step S307),
Exposure compensation amount setting means 71 or shutter switch (S
W1) Wait for 62 to be in the ON state. AE control 3
After the operation is performed, the system control circuit 50
Performs predetermined arithmetic processing using the image signal data from
Based on the obtained calculation result, the distance measurement processing is performed on the distance measurement control unit 44 to focus the focusing system lens 11 on the subject, and the AF control is performed (step S308).

Subsequently, the system control circuit 50 performs the AE control 4 for reflecting the exposure correction canceled as described above (step S700). The details of the AE control 4 will be described later.

Next, the shutter switch (SW2) 64
Is pressed (step S309), the main exposure for photographing the image to be recorded is performed (step S310). The details of the main exposure will be described later. Finally, via the interface 90 or the interface 94, the connector 92 or the connector 96, the recording medium 200 or the recording medium 21 such as a memory card or a compact flash card.
0 is written to the image data (step S31).
1). If the shutter switch (SW2) 64 is not pressed, the process waits until the shutter switch (SW1) 62 is pressed.

Next, AE control 1 will be described with reference to FIGS. FIG. 6 is a flowchart showing a control operation in the AE control 1.

The system control circuit 50 controls the exposure control means 4
0 (step S401), and the activated exposure control means 40 sets the appropriate exposure flag to 0 (step S4).
02). Subsequently, an initial setting of the photometry means such as a photometry area setting required for photometry is performed (step S403). Next, the system control circuit 50 activates the exposure control calculation means, initializes the subject brightness (Bv) value and the imaging sensitivity (Sv) value (step S404), and the exposure control value calculation means is not shown. From the program diagram, the aperture control (Av) value,
An electronic shutter control (Tv) value is analyzed and calculated (step S405), and control is performed by an aperture unit (step S406) and an electronic shutter unit (step S407).

Subsequently, the system control circuit 50 reads out the signal (step S408) exposed to the image pickup device 14 using the memory control 22 and the timing generator 18 (step S409), and the image processing circuit 20 reads out the signal. The luminance output Yout is derived from the signal via the A / D converter (step S410). Subsequently, the system control circuit 5
0 takes the ratio between the luminance output Yout from the image processing circuit and the target luminance level Yref, and derives the average (step S411).

Subsequently, the system control circuit 50 calculates the deviation (ΔBv) from the appropriate exposure level (step S 412) and the subject brightness (Bv) (step S 413) from the above average of the ratio between Yout and Yref. Derive.

After obtaining the subject brightness (Bv) and the ΔBv value, if the ΔBv value reaches an appropriate exposure level and falls within a preset error (± n) (step S414), the appropriate exposure flag is set to 1. (Step S415). ΔBv
If the value has not reached the appropriate exposure level (step S4
14), input the Bv value to the exposure control value calculation means (step S415), and repeat the operation of controlling the aperture means and the electronic shutter means to drive it into a predetermined range (step S4).
05 to S414).

Thus, the AE control 1 ends (step S416).

Next, AE control 2 will be described with reference to FIGS. FIG. 7 is a flowchart showing a control operation in the AE control 2.

The system control circuit 50 outputs the subject luminance (Bv) value and the imaging sensitivity (SV) output from the AE control 1 described above.
v) The value is input to the exposure control value calculation means (step S50)
2) The exposure control value calculating means analyzes and calculates the aperture control (Av) value and the electronic shutter control (Tv) value from a program diagram (not shown) (step S50).
2) Control is performed by the aperture means (step S503) and the electronic shutter means (step S504).

Subsequently, the system control circuit 50 reads out the signal (step S505) exposed to the image pickup device 14 using the memory control 22 and the timing generator 18 (step S506), and the image processing circuit 20 reads out the signal. The luminance output Yout is derived from the signal via the A / D converter (step S507). Subsequently, the system control circuit 5
0 takes the ratio between the luminance output Yout from the image processing circuit and the target luminance level Yref, and derives the average (step S508).

Subsequently, the system control circuit 50 calculates the deviation (ΔBv) from the appropriate exposure level (step S 509) and the subject brightness (Bv) (step S 510) from the average of the ratios of the above Yout and Yref. Derive.

After obtaining the subject brightness (Bv) and the ΔBv value, if the ΔBv value reaches an appropriate exposure level and falls within a preset error (± n) (step S511), the appropriate exposure flag is set to 1. (Step S512). ΔBv
If the value has not reached the appropriate exposure level (step S5
11), input the Bv value to the exposure control value calculation means (step S502), and repeat the operation of controlling the aperture means and the electronic shutter means to drive it into a predetermined range (step S5).
02 to S511).

After the exposure flag is set to 1 (step S512), the system control circuit 50 reads the exposure correction amount α (step S513), and performs exposure correction by subtracting the exposure correction amount α from ΔBv. (Step S514), a subject brightness (Bv) value is calculated (Step S515).

Thus, the AE control 2 ends (step S516).

Next, the AE control 3 will be described with reference to FIGS. FIG. 8 is a flowchart showing a control operation in the AE control 3.

The system control circuit 50 controls the subject brightness (Bv) value and the imaging sensitivity (S
v) The value is input to the exposure control value calculation means (step S60)
2) The exposure control value calculating means analyzes and calculates the aperture control (Av) value and the electronic shutter control (Tv) value from a program diagram (not shown) (step S60).
2) The control is performed by the aperture means (step S603) and the electronic shutter means (step S604).

Subsequently, the system control circuit 50 reads out the signal that has been exposed to the image pickup device 14 (step S605) using the memory control 22 and the timing generator 18 (step S606), and the image processing circuit 20 reads out the signal. The luminance output Yout is derived from the signal via the A / D converter (step S607). Subsequently, the system control circuit 5
0 takes the ratio between the luminance output Yout from the image processing circuit and the target luminance level Yref, and derives the average (step S608).

Subsequently, the system control circuit 50 calculates the deviation amount (ΔBv) from the appropriate exposure level (step S 609) and the subject luminance (Bv) (step S 610) from the average of the above ratios of Yout and Yref. Derive.

After obtaining the subject brightness (Bv) and the ΔBv value, if the ΔBv value reaches an appropriate exposure level and falls within a preset error (± n) (step S611), the appropriate exposure flag is set to 1. (Step S612). ΔBv
If the value has not reached the appropriate exposure level (step S6)
11) The Bv value is input to the exposure control value calculation means (step S602), and the operation of controlling the aperture means and the electronic shutter means to drive it into a predetermined range is repeated (step S6).
02 to S611).

Thus, the AE control 3 ends (step S613).

Next, the AE control 4 will be described with reference to FIGS. The AE control 4 performs the same operation as the AE control 3 and will be described with reference to FIG.

The system control circuit 50 controls the subject brightness (Bv) value and the imaging sensitivity (S
v) The value is input to the exposure control value calculation means (step S50)
2) The exposure control value calculating means analyzes and calculates the aperture control (Av) value and the electronic shutter control (Tv) value from a program diagram (not shown) (step S50).
2) Control is performed by the aperture means (step S503) and the electronic shutter means (step S504).

Subsequently, the system control circuit 50 reads out the signal (step S505) exposed to the image pickup device 14 using the memory control 22 and the timing generator 18 (step S506), and the image processing circuit 20 reads out the signal. The luminance output Yout is derived from the signal via the A / D converter (step S507). Subsequently, the system control circuit 5
0 takes the ratio between the luminance output Yout from the image processing circuit and the target luminance level Yref, and derives the average (step S508).

Subsequently, the system control circuit 50 calculates the deviation (ΔBv) from the appropriate exposure level (step S 509) and the subject brightness (Bv) (step S 510) from the above average of the ratio between Yout and Yref. Derive.

After obtaining the subject brightness (Bv) and the ΔBv value, if the ΔBv value reaches an appropriate exposure level and becomes a preset error (± n) (step S511), the appropriate exposure flag is set to 1 (Step S512). If the ΔBv value has not reached the appropriate exposure level (step S51)
1) The Bv value is input to the exposure control value calculation means (step S502), and the operation of controlling the aperture means and the electronic shutter means to drive it into a predetermined range is repeated (step S50).
2 to S511).

After the exposure flag is set to 1 (step S512), the system control circuit 50 reads the exposure correction amount α (step S513), and subtracts the exposure correction amount α from ΔBv to perform the exposure control 2. The canceled exposure correction is reflected again (step S514), and a subject brightness (Bv) value is calculated (step S515).

Thus, the AE control 4 ends (step S516).

Next, the main exposure will be described.

The main exposure is performed by the AE control 4 with the Av value and the Tv value that are appropriate for the Bv value obtained by adding and subtracting the finally determined correction amount.

As a method of determining the Av value and the Tv value at the time of the main exposure, the following cases can be considered.

The Bv value before correction is corrected by changing only the Av value.

The Bv value before correction is corrected by changing only the Tv value.

For the Bv value before correction, the Av value, Tv
Change and correct each value.

When the image display unit 28 is turned on, the exposure correction amount α by the operation of the exposure correction amount setting means 71 is set.
Is reflected on the image display unit 28.

As a result, the operator can confirm whether or not the exposure correction meets the operator's intention.

Further, by canceling the exposure correction amount α before the AF control, an exposure level appropriate for the AF control can be obtained.

The operations shown in FIGS. 2, 3, 5 to 8 are executed in accordance with an instruction from the system control circuit 50 based on a program stored in the memory 52.

As described above, in this embodiment, by performing the exposure correction outside the exposure control loop, the exposure-corrected image is
In a non-saturated range that does not exceed the full range of the A / D converter, the exposure is not corrected beyond the set exposure correction amount, so that the exposure correction can be performed according to the intention of the camera operator.

Further, by displaying the LCD at the time of the exposure correction, the camera operator can confirm the image on which the set exposure correction amount is reflected.

Further, by canceling the set exposure correction amount before the automatic focus control, an appropriate exposure level can be obtained for the automatic focus control.

In this embodiment, the recording medium 200 and the recording medium 210 include not only a memory card such as a PCMCIA card or a compact flash, a hard disk, but also a micro DAT, a magneto-optical disk, a CD-R or a CD-R.
An optical disk such as a D-WR or a phase change optical disk such as a DVD may be used. Further, the recording medium 200 and the recording medium 210 may be a composite medium in which a memory card and a hard disk are integrated. Further, a configuration may be adopted in which a part of the composite medium is detachable.

In this embodiment, the recording medium 2
00 and the recording medium 210 have been described as detachable recording media that are separated from the image processing apparatus 100 and can be arbitrarily connected, but any or all of the recording media may be the image processing apparatus 1.
It may be fixed at 00. Further, the recording medium 200 or the recording medium 210 is stored in the image processing apparatus 100.
However, a configuration in which one or a plurality of arbitrary numbers can be connected may be employed.

Then, the recording medium 2 is stored in the image processing apparatus 100.
Although the configuration in which the recording medium and the recording medium 210 are mounted has been described, the recording medium may be a single or a plurality of combinations.

Further, in this embodiment, the image display is performed by the image display section in the present apparatus. However, instead of the image display section 28 composed of a TFT LCD or the like, a video amplifier and a video signal output terminal are provided. The same effect is exhibited when displaying on an external display device or when transferring and displaying image data to an external device using the communication means 110 and the connector 112.

[0144]

As described above, according to the present invention,
There is an effect that exposure correction according to a user's intention can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an imaging device according to first and second embodiments.

FIG. 2 is a flowchart showing a control operation in a main routine according to the first embodiment.

FIG. 3 is a flowchart showing an exposure control operation according to the first embodiment;

FIG. 4 shows A / D in exposure control according to the first embodiment.
Diagram showing luminance signal during conversion

FIG. 5 is a flowchart showing a control operation in a main routine according to a second embodiment.

FIG. 6 is a flowchart showing a control operation in exposure control 1 according to a second embodiment.

FIG. 7 is a flowchart showing a control operation in exposure controls 2 and 4 according to a second embodiment.

FIG. 8 is a flowchart showing a control operation in exposure control 3 according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnification lens 11 Focusing lens 12 Shutter (light amount adjustment means) 14 Image sensor (photometry means) 15 Imaging sensitivity adjustment means 40 Exposure control means 42 Distance measurement control means 44 Zoom control means 46 Barrier control means 50 System control circuit 60 Mode dial switch 62 Shutter switch (SW1) 64 Shutter switch (SW2) 71 Exposure compensation amount setting means

Claims (10)

[Claims] 1. An imaging optical system including a light amount adjusting unit for adjusting an amount of light incident on an imaging device, a photometric unit for measuring an amount of light incident on the imaging device via the imaging optical system, and the measurement An exposure control unit that controls the amount of incident light by controlling the light amount adjustment unit based on the result, and an exposure correction amount setting unit that sets an exposure correction amount. The exposure correction amount is set by the exposure correction amount setting unit. When the correction is performed, the control value of the exposure control unit calculated based on the measurement result is corrected based on the exposure correction amount set by the exposure correction amount setting unit. 2. The imaging apparatus according to claim 1, wherein the exposure control means can change a control value regardless of a measurement result. 3. The light amount adjusting means is a light amount adjusting diaphragm,
The image pickup apparatus according to claim 1, wherein the exposure control unit controls an aperture of the light amount adjusting diaphragm. 4. The imaging apparatus according to claim 1, wherein the photometric unit is an imaging device. 5. The imaging apparatus according to claim 1, wherein the control value is a value for controlling an accumulation time of the imaging device. 6. A light amount incident on the image pickup device is measured by a photometric unit via an image pickup optical system including a light amount adjustment unit for adjusting a light amount incident on the image pickup device, and the light amount is measured based on the measurement result. When the exposure compensation amount is controlled by the exposure compensation amount setting unit that controls the adjusting unit to control the incident light amount by the exposure control unit and sets the exposure compensation amount,
A control method of an imaging apparatus, wherein a control value of the exposure control means calculated based on the measurement result is corrected based on an exposure correction amount set by the exposure correction amount setting means. 7. The method according to claim 6, wherein the exposure control means can change the control value regardless of the measurement result. 8. The light amount adjusting means is a light amount adjusting diaphragm,
8. The method according to claim 6, wherein the exposure control means controls an aperture of the light amount adjusting aperture. 9. The method according to claim 6, wherein the photometric device is an image sensor, and the incident light amount is measured by the image sensor. 10. The control value is a value for controlling the accumulation time of the imaging device, and the exposure control means controls the accumulation time of the imaging device.
The control method of any one of the imaging devices.