JP3143245B2 - Imaging device, photometric method therefor, focusing control method therefor, and imaging method - Google Patents

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 photographing a subject using a solid-state electronic image pickup device, such as a video camera, and outputting a video signal or image data representing the subject, a photometric method therefor, and a focus control method therefor. The present invention relates to an imaging method.

[0002]

2. Description of the Related Art In an imaging apparatus such as a video camera, an object is photographed using a solid-state electronic imaging device (for example, a CCD). It can be said that this solid-state electronic image sensor has subject information for each pixel.
A solid-state electronic imaging device having 1024 pixels arranged vertically in 80 pixels has about 1.3 million information.

In a video camera provided with a solid-state electronic imaging device and obtaining a video signal representing a subject image, a method of obtaining a photometric value by integrating a video signal output from the solid-state electronic imaging device over an appropriate photometric region. A method has been considered in which focusing control of an imaging lens is performed by integrating a video signal over a wide ranging area. In these systems, if there is a portion where the video signal is saturated in the photographing area in order to increase the accuracy, the portion is generally removed.

[0004] Since the solid-state electronic image pickup device has information for each pixel, determination of a saturated portion of a video signal and elimination thereof in a method of performing photometry using a video signal and a method of performing focus control are performed for each pixel. preferable.

However, it is difficult to process video signals or image data for each pixel with a small microcomputer even if storage in an image memory is taken into consideration, and it is not practical.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a method for obtaining photometric data, data for focusing control of an imaging lens, and the like in units of blocks larger than pixels when an object is photographed using a solid-state electronic imaging device. The purpose is to do.

An imaging apparatus according to a first aspect of the present invention includes a solid-state electronic imaging device, imaging means for photographing a subject, and outputting a video signal representing a subject image from the solid-state electronic imaging device, and an imaging area of the solid-state electronic imaging device. Block setting means for dividing an arbitrary area of the image into a plurality of blocks, a luminance signal extracting means for extracting a component relating to a luminance signal from a video signal output from the photographing means, and a luminance signal output from the luminance signal extracting means. The components are added in the range of the horizontal scanning period and the vertical scanning period corresponding to each block set by the block setting means, respectively,
An adding means for outputting an added luminance signal component for each block, a selecting means for selecting a non-saturated added luminance signal component among the added luminance signal components output from the adding means, and a selecting means for selecting the added luminance signal component. A photometric value calculating unit for calculating a photometric value based on the added luminance signal component is provided.

[0008] The first invention also provides a photometric method suitable for the above device. That is, this method divides an arbitrary region in the imaging region of the solid-state electronic image pickup device into a plurality of blocks, includes the solid-state electronic image pickup device, photographs a subject, and converts a video signal representing a subject image into the solid-state electronic image pickup device. From the element,
A component related to a luminance signal is extracted from the obtained video signal,
The components related to the extracted luminance signal are added in the range of the horizontal scanning period and the vertical scanning period corresponding to each of the divided blocks, and an added luminance signal component for each block is obtained. Among them, an added luminance signal component that is not saturated is selected, and a photometric value is calculated based on the selected added luminance signal component.

According to the first aspect, a component relating to a luminance signal is obtained in block units. When the component relating to the obtained luminance signal is saturated, a non-saturated luminance signal component is selected. The photometric value is calculated using the luminance signal component that is not saturated. Since the saturated luminance signal component is excluded, a highly accurate photometric value can be obtained. The components related to the luminance signal include a signal that can be regarded as a luminance signal such as a G signal in addition to a pure luminance signal.

According to a second aspect of the present invention, there is provided an imaging optical system including a solid-state electronic imaging device for converting an incident light image into a video signal and outputting the image signal, and an imaging lens for forming a subject image on the solid-state electronic imaging device. A block setting means for dividing an arbitrary region in the imaging region of the solid-state electronic imaging device into a plurality of blocks, extracting a high-frequency component for focusing control from a video signal output from the solid-state electronic imaging device; High-frequency signal component extraction means, and high-frequency signal components output from the high-frequency signal component extraction means are added in a range of a horizontal scanning period and a vertical scanning period corresponding to each block set by the block setting means, respectively. Adding means for outputting an added high-frequency signal component for each block; and among added high-frequency signal components output from the adding means, saturation. Selection means for selecting a to not adding the luminance signal component, and is characterized in that on the basis of the sum frequency signal component selected by said selecting means includes a combined control means for performing focus control of the imaging lens.

The second invention also provides a focusing control method suitable for the above device. That is, this method is applied to an imaging apparatus provided with an imaging optical system including a solid-state electronic imaging device that converts an incident optical image into a video signal and outputs the video signal and an imaging lens that forms a subject image on the solid-state electronic imaging device. Dividing an arbitrary area in the imaging region of the solid-state electronic imaging device into a plurality of blocks, extracting a high-frequency signal component for synthesis control from a video signal output from the solid-state electronic imaging device, and extracting the extracted high-frequency signal The components are added in the range of the horizontal scanning period and the vertical scanning period corresponding to each of the divided blocks, and an added high-frequency signal component for each block is obtained. Of the obtained added high-frequency signal components, the components are not saturated. An addition high-frequency signal component is selected, and focusing control of the imaging lens is performed based on the selected addition high-frequency signal component.

According to the second aspect, a high-frequency signal component is obtained for each block. When the obtained high-frequency signal component is saturated, a non-saturated high-frequency signal component is selected. Focus control of the imaging lens is performed using the high-frequency signal component that is not saturated. Since a saturated high-frequency signal component is excluded, high-precision focusing control can be performed.

An imaging apparatus according to a third aspect of the present invention captures a subject using a solid-state electronic imaging device, obtains a component related to a luminance signal representing the subject image, and divides an arbitrary region in the imaging region of the solid-state electronic imaging device. In the imaging apparatus for obtaining the added luminance signal component by adding the components related to the luminance signal for each of the plurality of first blocks obtained by performing the above operation, based on the added luminance signal component obtained for each of the first blocks, Main subject position detecting means for detecting the position of the main subject in the photographing area; of the photographing area, an area corresponding to the position of the main subject detected by the main subject position detecting means is set to be smaller than the first block; Block setting means for dividing into a plurality of small second blocks; and an added luminance signal for each second block divided by the block setting means. Adding means for outputting the component, as well as output from the adder means, characterized in that it comprises a weighted metering value calculating means for calculating a photometric value on the basis of the sum the luminance signal component for each second block.

The third invention also provides a photometric method suitable for the above device. That is, in this method, an object is photographed using a solid-state electronic imaging device, a component relating to a luminance signal representing the object image is obtained, and a plurality of regions obtained by dividing an arbitrary region in the imaging region of the solid-state electronic imaging device are obtained. In an imaging apparatus that obtains an added luminance signal component by adding the components related to the luminance signal for each of the first blocks, a main image signal in the imaging region is obtained based on the added luminance signal component obtained for each of the first blocks. Detects the position of the subject,
The area corresponding to the detected position of the main subject is divided into a plurality of second blocks smaller than the first block,
A second added luminance signal component for each of the divided second blocks is obtained, and a photometric value is calculated based on the obtained second added luminance signal component.

According to the third invention, a plurality of the first blocks are set in the photographing area. The first
The added luminance signal component for each block is obtained, and the position of the main subject is detected based on the obtained added luminance signal component. Further, an area corresponding to the detected position of the main subject in the photographing area is divided into a plurality of second blocks smaller than the first block. Then, the second
, The added luminance signal component is obtained for each block, and the photometric value is calculated.

The calculated photometric value is a weighted photometric value indicating the brightness of the main subject. The brightness of the main subject can be measured relatively accurately. In particular, since the size of the second block is smaller than that of the first block, by obtaining an added luminance signal component obtained from the second block in an area approximating the shape of the main subject, only the main subject is obtained. The brightness of the image can be measured more accurately.

According to a fourth aspect of the present invention, a subject is photographed by using a solid-state electronic imaging device in which a subject image is formed on a light receiving surface by an imaging lens, and a video signal representing the subject image is obtained. Extract high frequency signal components for focus control,
An imaging apparatus for adding an extracted high-frequency signal component to obtain an added high-frequency signal component for each of a plurality of first blocks obtained by dividing an arbitrary region in the imaging region of the extracted solid-state electronic imaging device. Main subject position detecting means for detecting the position of the main subject in the photographing area based on the added high-frequency signal component obtained for each of the first blocks, and detecting the main subject position detecting means in the photographing area A second block dividing unit that divides the region corresponding to the position of the main subject into a plurality of second blocks smaller than the first block, and each second block divided by the block dividing unit. Adding means for outputting the added high frequency signal component of the second block, and the added high frequency signal component for each second block output from the adding means. Characterized in that it comprises a priority focus control means for performing focusing control of the imaging lens based on.

The fourth invention also provides a focusing control method suitable for the above-mentioned imaging device. That is, in this method, a subject is photographed by using a solid-state electronic imaging device in which a subject image is formed on a light receiving surface by an imaging lens, a video signal representing the subject image is obtained, and focusing control for focusing is performed from the obtained video signal. For each of a plurality of first blocks obtained by dividing an arbitrary region in the imaging region of the solid-state electronic image pickup device, and extracting the extracted high-frequency signal components for the first block. In the imaging apparatus that obtains the added high-frequency signal component, the position of the main subject in the imaging region is detected based on the obtained first added high-frequency signal component. The region corresponding to the position is divided into a plurality of second blocks smaller than the first block, and a second added high-frequency signal component for each of the divided second blocks is obtained. Based on second adding high-frequency signal components and performs focus control of the imaging lens.

According to the fourth aspect, a plurality of the first blocks are set in the photographing area. The first
, And the position of the main subject is detected based on the obtained added high-frequency signal component. Further, an area corresponding to the detected position of the main subject in the photographing area is divided into a plurality of second blocks smaller than the first block. Then
An added high-frequency signal component is obtained for each second block, and focus control of the imaging lens is performed.

Since the size of the second block is smaller than that of the first block, an added high-frequency signal component obtained from the second block in an area approximating the shape of the main subject is obtained. Focus control of the imaging lens can be performed so that only the main subject is focused.

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

An embodiment in which the present invention is applied to a digital still camera will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a digital audio system according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an electric configuration of the still camera.

A clock signal generating circuit (hereinafter referred to as CG) 1 includes a clock signal CK, a horizontal transfer pulse for driving a horizontal transfer path of the CCD 6, a substrate removal pulse for discharging unnecessary charges, an A field vertical transfer pulse, A B field vertical transfer pulse is generated and given to the CCD 6.

The clock signal CK is supplied to a synchronizing signal generation circuit (hereinafter referred to as SSG) 2, and the SSG 2 generates a horizontal synchronizing signal HD and a vertical synchronizing signal VD based on the clock signal CK, and supplies them to CG1.

The horizontal synchronizing signal HD and the vertical synchronizing signal VD
Is provided from CG1 to the gate array 20. A clock signal ADCK having a cycle corresponding to the pixel data read cycle is generated in CG 1 and applied to gate array 20.

A subject image formed by the imaging lens 3 is formed on a CCD 6 via an aperture 4 and an optical low pass filter (OLPF) 5. The imaging lens 3 is positioned at an in-focus position by a lens driving motor 18 driven by a driver 16 controlled by the CPU 15, and the aperture 4 obtains an appropriate exposure amount by a motor 17 driven by the driver 16 controlled by the CPU 15. Driven so that

In the CCD 6, interlaced photographing is performed by a substrate removal pulse, an A-field vertical transfer pulse, a B-field vertical transfer pulse, and a horizontal transfer pulse, and the A-field and B-field video signals (GRRGB)
Are sequentially generated for each field period and sequentially read out. The driving of the CCD 6 (imaging and reading out of a video signal) is performed at least at the time of photographing and in the photometric processing preceding it.

The A-field and B-field video signals output from the CCD 6 are supplied to a color separation circuit 8 through a pre-amplification circuit 7, and the three primary colors G and G representing a subject image are output.
(Green), R (red) and B (blue) color signals.

The color signals G, R and B are input to a resampling circuit 10 after a color balance is adjusted by a gain control circuit (hereinafter referred to as GCA) 9.

The resampling circuit 10 reconverts the three color signals R, G, and B into color sequential signals of RGB,. This color-sequential signal is amplified to an appropriate level necessary for recording, converted into digital image data, and further converted into digital image data by an image data processing circuit (not shown).
After processing such as / C separation and data compression, the data is recorded on a recording medium such as a memory card.

Prior to photographing, focusing control processing of the imaging lens 3 and photometric processing and exposure control (control of aperture and shutter speed) based on photometric values are performed.

The focusing control processing of the imaging lens 3 is performed based on the output signal of the resampling circuit 10. A band pass filter (BPF) 11 is provided for focusing control processing of the imaging lens 3. The BPF 11 is a circuit for extracting a high-frequency signal component necessary for focusing processing from an input color sequential signal.

When the image pickup lens 3 is at the in-focus position, the image is clear, so that there are many high-frequency signal components. On the other hand, when the imaging lens 3 is not at the in-focus position, the image is blurred, so that the high-frequency signal component is small. In the digital electronic still camera shown in FIG. 1, the imaging lens 3 is positioned at the in-focus position in consideration of such points. In performing focusing control of the imaging lens 3, preliminary ranging is performed by a preliminary ranging sensor (not shown), and the imaging lens is positioned at an initial position close to the focusing position.

The color sequential signal output from the resampling circuit 10 is supplied to a BPF 11, where a high-frequency signal component for controlling the focusing of the image pickup lens 3 is extracted.
Provided to _one terminal. High frequency signal component switch circuit 13 is a conductive state S ₁ terminal while the focus control of the imaging lens 3 is performed is given to an analog / digital conversion circuit 14, converted into digital data to gate array 20 Given.

The photometric processing is performed based on the output signal of the GCA 9. A Y signal synthesizing circuit 12 is provided for photometric processing. In Y signal synthesizing circuit 12, R given from GCA9, G, luminance signal from the B signal is generated, the luminance signal is applied to S ₂ terminal of the switch circuit 13.
The switch circuit 13 when the photometric process is performed is given to S ₂ terminal luminance signal is in a conductive state analog / digital conversion circuit 14, supplied are converted into digital data in the gate array 20.

In the gate array 20, the input high-frequency signal data or luminance data is added for each block (described later) set in the photographing area.
The addition result for each block is provided to the CPU 15.

The CPU 15 selects necessary data from the addition data (high-frequency component data or addition data) for each block input from the gate array 20, and
Focus control of the imaging lens 3 or exposure control based on photometric value calculation processing and photometric value calculation is performed.

The digital electronic still camera is capable of flash photography and includes a flash unit 19. The flash device 19 is controlled by the CPU 15 to emit light.

FIG. 2 is a block diagram showing the electrical configuration of the gate array. FIG. 3 shows the photographing area of the CCD 6 as m × n.
The figure shows a state where the image is divided into a plurality of blocks. FIG.
Shows the relationship between the shooting area divided into a plurality of 16 × 16 blocks and the main subject, (A) is an example of a block division method, and (B) is another block division method. (C) shows a method of setting a block in a portion where the main subject exists.

FIGS. 5 to 7 are time charts showing the operation of the gate array shown in FIG. 2, and FIG. 8 is for explaining the relationship between the addition operation in the register included in the gate array and the divided photographing area of the CCD 6. belongs to.

Referring mainly to FIGS. 2 and 8, the gate array 20 is a circuit that adds pixel data of one input image for each block and outputs the added pixel data for each block. AND gate 21, 18-bit addition circuit
The pixel data is added to one horizontal scanning line in one block Br by 22 and the horizontal register 23. The addition data of one horizontal scanning line in one block Br is supplied to a 21-bit addition circuit 24. By the 21-bit addition circuit 24, the AND gate 25 and the plurality of vertical registers 26, the addition data is added to one horizontal scanning line in one block Br in one block in the vertical direction. When the added data of the lowermost horizontal scanning line in one block Br is given to the 21-bit adding circuit 24, the given horizontal added data and the vertical data fed back from the vertical register 26 are output. The direction addition data is added, and the addition result is given to the first stage transfer register 27 of the plurality of transfer registers 27 as data BD for one block Br. The data is output from the data selector 28 as block addition data for each block Br.

As will be described later, when the horizontal reset signal * HRST signal (* is used instead of a bar) is supplied to the AND gate 21 at the start of the horizontal addition operation of each block, one of the 18-bit addition circuits 22 is used. Since the input becomes 0, the first pixel data of the new block is stored in the horizontal register 23. By applying a vertical reset signal * VRST signal (using * instead of a bar) to the AND gate 25, a plurality of vertical registers 26 are provided.
Is reset.

Hereinafter, the operation of the gate array will be described in detail.

The vertical synchronizing signal VD, output from CG1,
The horizontal synchronizing signal HD and the clock signal ADCK are applied to a timing generator 29 of the gate array 20. Further, the CPU 15 outputs a CPU write signal, a CPU read signal, width data representing a width of a block set in the photographing area, and a parameter, and supplies them to the timing generator 29 of the gate array 20. Based on these signals, the size and number of blocks set in the shooting area are determined.

Determine the horizontal size of the block based on the signal input to the timing generator 29 *
HRST signal, determines vertical size of block *
A VRST signal, a horizontal transfer clock HCK that determines the addition timing of the horizontal addition data for each block, a load clock LDCK that determines the read timing of the addition data for each block, and a data selector signal that determines the data output timing are generated.

Referring to FIG. 3, when an arbitrary region included in the photographing region is divided into a plurality of blocks, an effective range and an invalid range are defined in the photographing region. That is, the horizontal invalid range HM and the horizontal valid range HY, and the vertical invalid range VM and the vertical valid range VY are determined. In addition, a horizontal block width (number of pixels) HW and a vertical block width (number of lines) VW are determined to determine the number of blocks. These determined data are used as width data by the CPU.
15 to Gate Array 20 Timing Generator 29
Given to. These ranges and widths may be determined on a program of the CPU 15, may be stored in a memory associated with the CPU 15 in advance, or may be input by a user from an appropriate input device. Good.

Referring mainly to FIG. 2, FIG. 5 (B) and FIG. 6 (A), digital data (high-frequency component data for focusing control of the imaging lens 3 or photometric Is input to the gate array 20 on a pixel-by-pixel basis and applied to the 18-bit addition circuit 22. The adder circuit 22 adds the data stored in the horizontal register 23 fed back through the AND gate 21 to the input one-pixel data.
The horizontal register 23 stores a clock signal ADC for each pixel.
Each time K is given, the added data of the adding circuit 22 is taken in and temporarily stored.

The horizontal block width HW of the block Br
Is applied to the AND gate 21 at the L level every time corresponding to When the signal * HRST is applied, the output of the AND gate 21 becomes 0, so that the adding circuit 22 adds 0 to the input data. Therefore, the horizontal direction register 23
Means that the first pixel data of each block is stored every time the signal * HRST is input. The horizontal addition data of one block is sent to the next-stage 21-bit addition circuit 24 after the last pixel data of each block is added (that is, at the time of input of the signal * HRST).

The 18-bit addition circuit 22 defines a horizontal invalid range HM and a vertical invalid range VM from the CPU 15 and supplies a horizontal addition control signal HI and a vertical addition control signal VI for defining the addition range. The input data is added only while these signals HI and VI are at the L level.

The vertical synchronizing signal * VRS is applied to the AND gate 25.
When T is given, the first vertical register 26
Is supplied with data 0, the register 26 is reset. Since this data 0 is sequentially shifted, the vertical register 26 of each stage is sequentially shifted.
Is reset.

The addition data for one horizontal scanning line in one block Br input to the 21-bit addition circuit 24 is obtained by adding the vertical synchronization signal * VRST to one terminal.
First stage vertical 21-bit register through gate 25
Given to 26. The vertical registers 26 are provided by the same number as the number m of blocks in the horizontal direction, and a horizontal clock signal HCK synchronized with the horizontal reset signal * HRST is input to these clock input terminals. Therefore, as shown in FIG. 8 (A), when the addition data a _1,1 of one horizontal scanning line in the first block Br is input to the first-stage vertical integration register 26, then the horizontal clock signal HCK is generated. The horizontal addition data a _1,1 in the first block Br is sequentially shifted synchronously, and shifted to the second-stage vertical register 26 to be shifted to the first-stage vertical register 26.
Has horizontal addition data a in the second block Br.
_2,1 will be entered. Thereafter, in the same manner, the sequential shift operation and the operation of inputting the horizontal addition data of the next block Br to the first-stage vertical register 26 are repeated. Then, the horizontal addition data of all the blocks in the effective range is stored in all the vertical registers 26. That is, the horizontal addition data am _{, 1} of the block Br at the right corner is stored in the vertical register 26 of the first stage as shown in FIG. The horizontal addition data am _{-1,1 of the} second block Br from the corner is stored,
The vertical register 26 at the m-th final stage stores the horizontal addition data a _1,1 of the block Br at the left corner.

When the horizontal addition data of all the blocks is input to the vertical direction register 26, the horizontal addition data a _1,2 of the second pixel is set to 21 in the vertical direction of the block Br at the left corner as shown in FIG. 8C. It is input to the bit addition circuit 24. The horizontal addition data a _1,1 in the block Br at the left corner stored in the vertical register 26 at the last stage is input to the 21-bit addition circuit 24. Thus, the horizontal addition data a _1,1
And a _1,2 are added in a 21-bit adding circuit 24.
The result of this addition is stored in the first stage register 26 by an AND gate.
Given through 25. While the data in the register 26 is sequentially shifted, the addition circuit 24 performs vertical addition in each block, and outputs the addition result to the register 26.
Stored in 26.

The addition data is applied to the last horizontal line in each block from the horizontal integration register 23 to the 21-bit addition circuit 24, and the final stage 21-bit register 26
Is supplied to the 21-bit adder circuit 24, the data is added to each other, and the integrated data B for one block Br is added.
D is obtained (see FIG. 8D). The integrated data BD for one block Br is supplied to the transfer register 27.

The transfer registers 27 are provided by the number corresponding to the number m of blocks in the horizontal direction. Each block Br is connected to the clock input terminal of the transfer 21-bit register 27.
Of the load clock signals LDCK appearing at a cycle corresponding to the vertical width VW of the clock signal. The period of the signal LDCK in the group of signals corresponds to the horizontal width HW.

When data BD for one block Br is input to the transfer 21-bit register 27, it is sequentially shifted and applied to the data selector 28 in response to the load clock signal LDCK. The data selector 28 is supplied with a data select signal from the timing generator 29. For example, if the data is 21-bit data, the data is sequentially output to the upper 5 bits, the middle 8 bits, and the lower 8 bits, and supplied to the CPU 15.

The CPU 15 is supplied with luminance data or data for focusing control for each block Br within the set effective range. Data can be identified in units of blocks, and divisional photometry, average photometry, or focusing control of the imaging lens 3 can be performed using only appropriate data, thereby improving the processing accuracy of each.

In the above description, one block of data is sequentially supplied to the transfer register 27, and the transfer register 27 is sequentially shifted and output. However, one block of data is temporarily stored in the vertical register. Alternatively, these data may be directly supplied to the transfer registers 27 corresponding to the respective vertical registers 26. In this case, it is preferable to input data to the CPU 15 in an order corresponding to the scanning direction of the screen by reversing the order of outputting data from the transfer register in the above embodiment.

The positions of the blocks can be shifted as shown in FIG. 4 (B). In this case, input to the transfer 21-bit register 27 is enabled or disabled according to whether the block is an odd-numbered column or an even-numbered column. By shifting the position of the block in the horizontal direction or the vertical direction, it becomes possible to cope with a round object.

Further, the position of the main object in the photographing area can be determined based on the luminance distribution of the object based on the luminance data or the distribution of the distance to the object based on the focus control data. Fig. 4 (C)
As shown in (1), it is also possible to focus on the main subject. In this case, the effective range in the horizontal direction HY and the effective range in the vertical direction VY are set so that the main subject is mainly measured.
Are defined respectively.

From the luminance data obtained in block units,
Only the data of the block whose luminance data is not saturated is selected, the photometric value is calculated based on the selected luminance data, and the control of the shutter speed of the aperture 4 and the CCD 6 is performed.

Only the data of the non-saturated block is selected from the focusing control data of the imaging lens 3 obtained in block units, the sum of the selected data is obtained, and the sum of the selected data is calculated based on the added data. Focus control is performed. While the imaging lens 3 is moved forward by 10 μm for focusing control, shooting and data integration are performed at each position at least six times (ie, in the B field period of each frame period over six frame periods). First, first focusing addition data is obtained at the above initial position (extending amount of the imaging lens 3 = 0 μm). In the next frame period, second focusing addition data is obtained at a position where the imaging lens 3 is extended by 10 μm from the initial position (imaging lens extension amount = 10 μm). Similarly, the third to sixth additional data for focusing are obtained while the imaging lens 3 is extended by 10 μm. The addition data at the six positions obtained in this manner is stored in a predetermined area of the memory as shown in FIG.

FIG. 10 is a graph showing the distance measurement addition data at the six positions shown in FIG. Imaging lens 3
The initial position is slightly before the true focus position. From this position, the imaging lens 3 is extended by 10 μm at a time, and focus addition data is obtained at each position. The integrated value of the high-frequency signal included in the video signal becomes maximum at the true focus position. Imaging lens 3
Is a very small distance at 10μm.
Even if the position at which the focusing addition data indicates the maximum value is regarded as a true focusing position, the error is extremely small. Therefore, high-precision focusing can be achieved by positioning the imaging lens 3 at a position where the focusing addition data indicates the maximum value.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a digital electronic still camera.

FIG. 2 is a block diagram illustrating a configuration example of a gate array.

FIG. 3 shows a plurality of blocks set in a shooting area.

FIGS. 4A to 4C show a relationship between a plurality of blocks set in a shooting area and a main subject.

FIGS. 5A and 5B are time charts for integrating and transferring data in a gate array.

FIGS. 6A and 6B are time charts showing a part of the time chart shown in FIG. 5 enlarged in time, and showing the integration timing of data.

FIG. 7 is a time chart showing a part of the time chart shown in FIG. 5 in a timely enlarged manner, and showing a data transfer output timing.

FIG. 8 shows how data is accumulated for each block.

FIG. 9 shows an example of a memory in which data for focus control is stored.

FIG. 10 is a graph showing data stored in the memory shown in FIG. 9;

[Explanation of symbols]

 Reference Signs List 3 imaging lens 4 aperture 6 CCD 8 color separation circuit 9 GCA 10 resampling circuit 11 BPF 12 Y signal synthesis circuit 15 CPU 20 gate array

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-84574 (JP, A) JP-A-4-101125 (JP, A) JP-A-4-175076 (JP, A) JP-A-4-175076 109775 (JP, A) JP-A-3-276975 (JP, A) JP-A-62-147872 (JP, A) JP-A-2-141880 (JP, A) JP-A-6-113192 (JP, A) JP-A-4-354277 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/222-5/257 G02B 7/11

Claims (8)

(57) [Claims] 1. An image pickup device including a solid-state electronic image pickup device, for photographing a subject, and outputting a video signal representing a subject image from the solid-state electronic image pickup device, a plurality of arbitrary regions in a photographing region of the solid-state electronic image pickup device. Block setting means for dividing a video signal output from the photographing means into a luminance signal extracting means for extracting a component relating to a luminance signal from the video signal output from the photographing means; Adding means for adding each of the blocks in the horizontal scanning period and the vertical scanning period corresponding to each of the blocks, and outputting an added luminance signal component for each block; home,
Selecting means for selecting an addition luminance signal component that is not saturated,
And a photometric value calculating means for calculating a photometric value based on the added luminance signal component selected by the selecting means. 2. An imaging apparatus comprising: a solid-state electronic imaging device that converts an incident light image into a video signal and outputs the image signal; and an imaging optical system including an imaging lens that forms a subject image on the solid-state electronic imaging device. Block setting means for dividing an arbitrary region in the imaging region of the solid-state electronic image sensor into a plurality of blocks; a high-frequency signal for extracting a high-frequency signal component for focus control from a video signal output from the solid-state electronic image sensor The high frequency signal component output from the high frequency signal component extracting means is added in the range of the horizontal scanning period and the vertical scanning period corresponding to each block set by the block setting means. Adding means for outputting an added high-frequency signal component of the added high-frequency signal component; No added high frequency signal components selecting means selects, as well as the focusing control unit selected on the basis of the sum frequency signal components selected by means performs a focusing control of the imaging lens, an imaging device provided with a. 3. A plurality of objects obtained by photographing a subject using a solid-state electronic imaging device, obtaining a component related to a luminance signal representing the subject image, and dividing an arbitrary region in the imaging region of the solid-state electronic imaging device. An imaging apparatus for adding a component related to the luminance signal for each first block to obtain an added luminance signal component, wherein the main subject in the imaging region is determined based on the added luminance signal component obtained for each first block. Main subject position detecting means for detecting the position of the main subject, and a plurality of second blocks smaller than the first block in an area corresponding to the position of the main subject detected by the main subject position detecting means in the photographing area. A block setting means for dividing the second block divided by the block setting means, an addition means for outputting an added luminance signal component for each of the second blocks;
And an important point photometric value calculating means for calculating a photometric value based on an added luminance signal component for each second block output from the adding means. 4. A subject is photographed by using a solid-state electronic imaging device in which a subject image is formed on a light receiving surface by an imaging lens.
It is obtained by obtaining a video signal representing a subject image, extracting a high-frequency signal component for focusing control from the obtained video signal, and dividing an arbitrary region in the imaging region of the extracted solid-state electronic imaging device. In an imaging apparatus for adding an extracted high-frequency signal component for each of a plurality of first blocks to obtain an added high-frequency signal component, an image pickup apparatus in the imaging region based on the added high-frequency signal component obtained for each of the first blocks Main subject position detecting means for detecting the position of the main subject, a plurality of areas smaller than the first block, which correspond to the position of the main subject detected by the main subject position detecting means, within the photographing area; A second block dividing unit that divides the added high frequency signal component of each second block divided by the block dividing unit into second blocks; Force adding means, and output from the adding means, focus focusing control means on the basis of the sum frequency signal component for each second block performs a focusing control of the imaging lens, an imaging device provided with a. 5. A solid-state image pickup device which divides an arbitrary region in a photographing region into a plurality of blocks, includes a solid-state image pickup device, photographs a subject, and transmits a video signal representing a subject image to the solid-state image pickup device. From the obtained video signal, extract the components related to the luminance signal, and add the extracted components related to the luminance signal in the range of the horizontal scanning period and the vertical scanning period corresponding to each of the divided blocks. A photometric method comprising: obtaining an added luminance signal component of the above; selecting a non-saturated added luminance signal component from the obtained added luminance signal components; and calculating a photometric value based on the selected added luminance signal component. 6. An imaging apparatus comprising: a solid-state electronic imaging device that converts an incident light image into a video signal and outputs the image signal; and an imaging optical system that includes an imaging lens that forms a subject image on the solid-state electronic imaging device. An arbitrary region in the imaging region of the solid-state electronic imaging device is divided into a plurality of blocks, a high-frequency signal component for focus control is extracted from a video signal output from the solid-state electronic imaging device, and the extracted high-frequency signal is extracted. The components are added in the range of the horizontal scanning period and the vertical scanning period corresponding to each of the divided blocks, and an added high-frequency signal component is obtained for each block. Of the obtained added high-frequency signal components, A focusing control method, comprising: selecting an added high-frequency signal component; and performing focusing control of the imaging lens based on the selected added high-frequency signal component. 7. A plurality of objects obtained by photographing a subject using a solid-state electronic imaging device, obtaining a component related to a luminance signal representing the subject image, and dividing an arbitrary region in the imaging region of the solid-state electronic imaging device. An imaging apparatus for adding a component related to the luminance signal for each first block to obtain an added luminance signal component, wherein the main subject in the imaging region is determined based on the added luminance signal component obtained for each first block. And divides an area corresponding to the detected position of the main subject into a plurality of second blocks smaller than the first block, and performs a second addition for each of the divided second blocks. A photometric method that obtains a luminance signal component and calculates a photometric value based on the obtained second added luminance signal component. 8. A subject is photographed using a solid-state electronic imaging device in which a subject image is formed on a light receiving surface by an imaging lens.
A video signal representing a subject image is obtained, a high-frequency signal component for focus control is extracted from the obtained video signal, and a plurality of regions obtained by dividing an arbitrary region in the imaging region of the solid-state electronic imaging device are obtained. In an imaging apparatus for obtaining a first added high-frequency signal component by adding the extracted high-frequency signal components for each first block, a main subject in the photographing area is obtained based on the obtained first added high-frequency signal component. And divides an area corresponding to the detected position of the main subject in the photographing area into a plurality of second blocks smaller than the first block. A second added high-frequency signal component for the block, and focusing control of the imaging lens based on the obtained second added high-frequency signal component.