JP2002209221A - Digital image pickup device and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital camera that can properly conduct exposure control and WB(White Balance) control. SOLUTION: The digital camera storing picked-up image in an image memory 209 as digital data is provided with a top/bottom discrimination section 265 that discriminates up and down directions (top and bottom directions) of an object in an image from the image in the image memory 209 and a photometry arithmetic section 266 and a colorimetry arithmetic section 267 that respectively conduct photometry and colorimetry arithmetic operations depending on the result of top/bottom discrimination. A timing control circuit 202 and an aperture driver 306 respectively receive an exposure time and an aperture value obtained by the photometry arithmetic operation and a WB circuit 207 receives a gain setting value obtained by the colorimetry arithmetic operation. Thus, the digital camera can properly conduct exposure control and WB control in response to the result of top/bottom discrimination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for performing photometry and colorimetry in a digital imaging device.

[0002]

2. Description of the Related Art In a digital still camera (hereinafter, referred to as a "digital camera"), there is known a technique for determining the vertical direction of a subject in an image based on the luminance of a plurality of photometric areas. For example, JP-A-2000-184271
Japanese Patent Application Laid-Open Publication No. H11-163873 discloses a technique for determining the vertical direction of a subject in an image from the luminance of a plurality of photometric areas and expanding the upper photometric area to more appropriately perform photometry.

[0003]

According to the technique described in the above publication, the shape of the photometric area at the center of the image is fixed. Therefore, when the direction of the digital camera is changed, the direction of the photometric region at the center of the screen with respect to the subject in the image also changes. Further, in the above publication, the entire image (that is, the object scene) is divided into a plurality of regions, so that when a light source is present at a corner of the image, it becomes difficult to perform appropriate photometry and exposure control.

On the other hand, when an image is obtained by a digital camera, white balance control is also performed. Conventional white balance control (hereinafter, referred to as “WB control”)
In, the hue is controlled without considering the vertical direction of the subject in the image. Therefore, when simultaneously photographing a fluorescent light and a main subject such as a person illuminated by a fluorescent light positioned above the object scene, the effect of the light source cannot be sufficiently corrected, and the face of the person turns green. It will take on.

The present invention has been made in view of the various problems described above, and has as its main object to appropriately perform photometry and colorimetry in a digital imaging device.

[0006]

According to a first aspect of the present invention, there is provided a digital imaging apparatus, comprising: an imaging unit that acquires an image of a subject as digital data; and a vertical direction of the subject in the image. A determination unit; and a control unit that controls the white balance while following the vertical direction.

According to a second aspect of the present invention, in the digital imaging device according to the first aspect, the discriminating means discriminates the vertical direction based on a plurality of discriminating areas set in the image. .

According to a third aspect of the present invention, there is provided the digital imaging apparatus according to the second aspect, wherein the control means is configured to follow a plurality of colorimetric areas set in the image while following the vertical direction. The colorimetric evaluation values for R, G, and B are obtained, and the white balance is controlled using the colorimetric evaluation values.

According to a fourth aspect of the present invention, there is provided the digital image pickup apparatus according to the third aspect, wherein the control means controls the R, G, and B of the image based on the plurality of colorimetric regions. A weighted sum of pixel values is determined, and the colorimetric evaluation value is determined using the weighted sum.

According to a fifth aspect of the present invention, in the digital imaging apparatus according to the fourth aspect, when the control means calculates the weighted sum, it measures the upper part of the image specified by the vertical direction. A weight coefficient corresponding to the color area is set to be larger than a weight coefficient corresponding to the color measurement area below the image.

According to a sixth aspect of the present invention, there is provided the digital imaging apparatus according to any one of the third to fifth aspects, wherein the plurality of determination areas and the plurality of colorimetric areas are set differently. .

[0012] According to a seventh aspect of the present invention, there is provided a recording medium recording a program for controlling a digital imaging device,
The execution of the program by the digital imaging device includes the steps of: obtaining, by the digital imaging device, an image of a subject as digital data; determining the vertical direction of the subject in the image; and performing white balance while following the vertical direction. And the step of controlling.

The invention according to claim 8 is a digital image pickup apparatus, wherein: an image pickup means for acquiring an image of a subject as digital data; And a photometric means for performing photometric calculation on a portion other than a peripheral portion of the image while performing the photometric operation while following the vertical direction.

According to a ninth aspect of the present invention, there is provided a recording medium recording a program for controlling a digital imaging device,
The execution of the program by the digital imaging device includes, in the digital imaging device, a step of acquiring an image of the subject as digital data, performing an operation on the entire image as an operation target, and performing the vertical direction of the object in the image. The step of performing the determination and the step of performing the photometric calculation on the portion excluding the peripheral portion of the image while following the vertical direction are to be calculated.

According to a tenth aspect of the present invention, there is provided a digital image pickup apparatus, comprising: an image pickup means for obtaining an image of a subject as digital data; and a plurality of determination regions set in the image. Determining means for determining the vertical direction of the subject; and photometric means for performing a photometric calculation based on a plurality of photometric areas different in setting form from the plurality of determination areas while following the vertical direction.

According to an eleventh aspect of the present invention, in the digital imaging device according to the tenth aspect, the number of the plurality of photometric areas is larger than the number of the plurality of determination areas.

According to a twelfth aspect of the present invention, there is provided the digital imaging apparatus according to the tenth or eleventh aspect, wherein the plurality of measurement areas having different setting modes from each of the plurality of determination areas and the plurality of photometry areas are provided. The image processing apparatus further includes control means for controlling white balance based on the color area.

According to a thirteenth aspect of the present invention, in the digital imaging device according to any one of the tenth to twelfth aspects, the discriminating unit and the photometric unit convert the same image acquired by the imaging unit. The processing is performed for this.

According to a fourteenth aspect of the present invention, there is provided a recording medium storing a program for controlling a digital imaging device, wherein the program is executed by the digital imaging device.
The digital imaging device, a step of acquiring an image of a subject as digital data, a step of determining the vertical direction of the subject in the image based on a plurality of determination areas set in the image, the vertical direction And performing a photometric calculation based on a plurality of photometric regions having a different setting form from the plurality of determination regions.

According to a fifteenth aspect of the present invention, there is provided a digital image pickup apparatus, wherein the image pickup means for obtaining an image of the subject as digital data, and the image pickup means based on a plurality of determination areas set in the image. Determination means for determining the vertical direction of the subject, and photometric means for performing photometric calculation based on a plurality of photometric areas set in the image while following the vertical direction, wherein the plurality of determination areas are set. And the image in which the plurality of photometric areas are set is the same, and the image is divided into a plurality of small blocks, and the plurality of determination areas and the plurality of photometric areas are based on the small blocks. The boundary between the plurality of determination areas and the boundary between the plurality of photometry areas are at least partially coincident with each other, and the determination in the vertical direction and the photometry calculation are performed. It is performed based on the value derived from the number of small blocks.

According to a sixteenth aspect of the present invention, in the digital imaging device according to the fifteenth aspect, in the photometric operation, a weighted sum of the luminance of each block is obtained based on the plurality of photometric regions, When obtaining the weighted sum, a weighting coefficient corresponding to a photometric area at the top of the image specified by the vertical direction is set to be larger than a weighting coefficient of a photometric area corresponding to a lower part of the image.

According to a seventeenth aspect of the present invention, there is provided a recording medium storing a program for controlling a digital imaging device, wherein the program is executed by the digital imaging device.
The digital imaging device, a step of acquiring an image of the subject as digital data, and a step of determining the vertical direction of the subject in the image based on a plurality of determination areas set in the image, the vertical direction Performing a photometric operation based on the plurality of photometric regions set in the image while following, the boundaries of the plurality of determination regions and the boundaries of the plurality of photometric regions, at least in part. Matches.

The invention according to claim 18 is a digital image pickup apparatus, wherein: an image pickup means for acquiring an image of a subject as digital data; a discrimination means for discriminating a vertical direction of the subject in the image; And a photometric unit that performs photometric calculation based on a plurality of photometric areas including the area that is long in the up-down direction at substantially the center of the image.

According to a nineteenth aspect of the present invention, there is provided a recording medium storing a program for controlling a digital imaging device, wherein the program is executed by the digital imaging device.
A step of acquiring an image of the subject as digital data in the digital imaging device; a step of determining the vertical direction of the subject in the image; and a plurality of photometry areas including a vertically long region substantially at the center of the image. And performing a photometric calculation based on the use area.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <1. Digital Camera Configuration>
FIGS. 1 to 3 are views showing a main part configuration of a digital camera 1 according to an embodiment of the present invention. FIG. 1 is a plan view, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. Figures and 3 correspond to rear views. These drawings do not always follow the triangular projection, and the main purpose is to conceptually illustrate the configuration of the main part of the digital camera 1.

As shown in FIGS. 1 to 3, the digital camera 1 has a structure roughly divided into a substantially rectangular parallelepiped camera body 2 and an image pickup section 3, and as shown in FIG. The imaging unit 3 includes a lens group 3 having a macro function as a photographing lens.
CCD (color area sensor) 3 in the right position behind 0
An imaging circuit 302 having an image sensor 03 is provided. Also,
The lens group 30 includes a zoom lens 300 and a focusing lens 30.
1 is provided.

On the other hand, inside the camera body 2, a zoom motor M1 for changing the zoom ratio of the zoom lens 300 and moving the lens between the accommodation position and the photographing position, and the focusing lens 301 are driven to focus. Motor M2 for performing scoring
Is provided. A pop-up built-in flash 5 is provided at an appropriate position at the upper end of the camera body 2.

On the other hand, as shown in FIG.
A shutter button 9 is provided on the upper surface of the camera.
A liquid crystal display (LCD) 10 and an electronic viewfinder (EVF) 20 for performing reproduction display of a recorded image and the like.
Are provided. The LCD 10 and the EVF 20 display images in color.

A shooting / playback mode setting switch 14 for switching between a "shooting mode" and a "playback mode" is further provided on the back of the camera body 2. The photographing mode is a mode for photographing, and the reproduction mode is a mode for reproducing and displaying a photographed image recorded on the memory card 8 (see FIG. 1) on the LCD 10.

On the right side of the back of the digital camera 1, a four-way switch 35 is provided. By pressing the buttons L and R, zooming is performed by the zoom motor M1, and various other operations are performed by the buttons U, D, L and R. An operation is performed.
The ON / OF of the LCD 10 is provided below the four switches 35.
There are provided an LCD button 31 for switching F, a decision button 32 for confirming selection of an item displayed on the LCD 10, a cancel button 33 for canceling selection of an item, and a menu button 34 for displaying a menu of various items.

An external monitor terminal 222 is provided on a side surface of the camera body 2. External monitor terminal 222
Is a terminal for transmitting image data and the like from the digital camera 1 to an external monitor.

As shown in FIG. 1, a digital camera 1 can be loaded with a memory card 8 as a recording medium, and the obtained image can be transferred to an external device using the memory card 8. . The operation program in the digital camera 1 can be updated by loading the operation program for the digital camera 1 stored in the memory card 8 into the digital camera 1.

FIG. 4 is a block diagram showing the configuration of the digital camera 1. In FIG. 4, the CCD 303 is
The light image of the subject formed by the lens group 30 is represented by R
The image signal is photoelectrically converted into an image signal of a color component of (red), G (green), and B (blue) (a signal composed of a signal sequence of pixel signals received by each pixel) and output.

The exposure control in the image pickup unit 3 is performed by controlling the aperture in the lens group 30 by the aperture control driver 306 and the CCD 3
03, that is, the charge accumulation time (exposure time) of the CCD 303 corresponding to the shutter speed is adjusted. If the appropriate exposure time cannot be set when the subject luminance is low, the improper exposure due to insufficient exposure is corrected by adjusting the level of the image signal output from the CCD 303. That is, when the luminance is low, the exposure control is performed by combining the exposure time with the gain adjustment by the signal processing circuit 313 described later.

The timing generator 314 generates a drive control signal for the CCD 303 based on the reference clock transmitted from the timing control circuit 202. The timing generator 314 generates clock signals such as integration start / end (exposure start / end) timing signals and readout control signals (horizontal synchronization signal, vertical synchronization signal, transfer signal, etc.) of the light receiving signal of each pixel, and the like. Output to the CCD 303.

The signal processing circuit 313 performs predetermined analog signal processing on an image signal (analog signal) output from the CCD 303. The signal processing circuit 313
It has a DS (correlated double sampling) circuit and an AGC (auto gain control) circuit. The CDS circuit reduces the noise of the image signal, and the level of the image signal is adjusted by adjusting the gain of the AGC circuit.

The dimming circuit 304 controls the light emission amount of the built-in flash 5 during flash photography to a predetermined light emission amount set by the overall control unit 211. In flash photography, reflected light of flash light from a subject is received by the light control sensor 305 at the same time as the start of exposure, and a light emission stop signal is output from the light control circuit 304 when the amount of received light reaches a predetermined light emission amount. The light emission of the built-in flash 5 is forcibly stopped in response to the light emission stop signal, and the light emission amount of the built-in flash 5 is controlled to a predetermined light emission amount.

The A / D converter 205 converts each pixel signal of the image signal into a 12-bit digital signal. The A / D converter 205 converts each pixel signal (analog signal) into a digital signal and performs an interpolation process based on an A / D conversion clock input from the timing generation circuit to obtain a 12-bit digital signal.

The timing control circuit 202 is controlled by a reference clock in the overall control unit 211, and includes not only the timing generator 314 and the signal processing circuit 313 but also A
A clock for the / D converter 205 is also generated.

The black level correction circuit 206 corrects the black level of the A / D converted pixel signal to a reference black level. In addition, a white balance circuit (hereinafter referred to as “WB
Circuit. " ) 207 performs level conversion of pixel data of each color component of R, G, and B. The WB circuit 207 converts the level of the pixel data of each of the R, G, and B color components using the level conversion table input from the overall control unit 211. Note that the parameters (gradients of characteristics) of each color component in the level conversion table are automatically set by the overall control unit 211 for each captured image.

The gamma correction circuit 208 corrects the gradation of pixel data. The image memory 209 is a memory that stores digital data output from the gamma correction circuit 208, that is, an image obtained by shooting. The image memory 209 has a storage capacity of one frame (for example, 2100 × 1400) of pixel data corresponding to the number of pixels of the CCD 303, and each pixel data is stored in a corresponding pixel position.

The VRAM 210 is a buffer memory for image data displayed on the LCD 10. VRAM 210
Has a storage capacity of image data corresponding to 400 × 300 pixels of the LCD 10.

Another VRAM 220 is an EVF 20
Is a buffer memory for image data displayed on the screen. VR
The AM 220 has a storage capacity of image data corresponding to the number of pixels 640 × 480 of the EVF 20.

In the photographing standby state, the imaging unit 3
After subjecting each pixel data of an image captured every 1/30 (second) to predetermined signal processing by the A / D converters 205 to γ correction circuit 208, the pixel data is temporarily stored in the image memory 209, VRAM2 via the overall control unit 211
10 and the VRAM 220, and the LCD 10 and E
It is displayed on the VF 20 (live view display).

Thus, the user can visually recognize the subject image in real time. In the reproduction mode, after the image read from the memory card 8 is subjected to predetermined signal processing by the overall control unit 211, the VRAM 2
10 and reproduced and displayed on the LCD 10. EVF
A similar display is performed on 20.

The card I / F 212 is an interface for writing image data to the memory card 8 and reading image data. Also, communication I / F2
Reference numeral 24 denotes an interface conforming to, for example, the USB standard for externally connecting the personal computer 225 so that communication is possible. Card I / F 212 and communication I
/ F224 via the memory card 8 or the CD-ROM 2
The control program recorded on a recording medium such as 26 can be loaded into the ROM of the overall control unit 211.

The RTC 219 is a clock circuit for managing the shooting date and time, and is driven by a power supply different from the power supply of the main body.

The NTSC converter 221 has a VRAM 220
Is converted into an NTSC format signal and transferred to the external monitor 223 via the EVF 20 and the external monitor terminal 222.

The operation unit 250 corresponds to various switches and buttons such as the shutter button 9, LCD button 31, and enter button 32 described above.

The shutter button 9 is in a half-pressed state and a depressed state (fully pressed) as employed in a silver halide camera.
Are two-stage switches that can be detected. When the shutter button 9 is half-pressed in the standby state, auto focus control (hereinafter, referred to as “AF control”) is started, and
While evaluating the contrast of the image in the image memory 209, the overall control unit 211 controls the motor M2 so that the contrast becomes highest, and moves the focusing lens 301 to the focusing position. Further, the image memory 20 at the time of half-pressing is
Exposure control is performed based on the photometric calculation described later based on the image data in the image data 9, and WB control based on the colorimetric calculation is performed.

The overall control unit 211 is composed of a microcomputer, and controls the driving of each member of the camera described above in an organic manner to control the photographing operation of the digital camera 1 overall.

The overall control unit 211 records an image obtained by photographing on the memory card 8 and stores an image recorded on the memory card 8 on the LCD 10 or the EVF 20 in addition to the AF control, the photometric operation and the colorimetric operation. Processing for reproduction is also performed.

When an image is recorded, the overall control unit 21
1 reads out image data from the image memory 209 and generates a thumbnail image and a compressed image to be recorded on the memory card 8. Specifically, pixel data is read out from the image memory 209 every eight pixels in both the horizontal direction and the vertical direction, and is sequentially transferred to the memory card 8 to generate and record a thumbnail image. Next, data of all pixels is read from the image memory 209, and the two-dimensional D
The image data of the compressed image is generated and recorded by performing a predetermined compression process by the JPEG method such as the CT conversion and the Huffman coding.

When the photographing / reproduction mode setting switch 14 is set to the reproduction mode, the data of the image having the largest frame number in the memory card 8 is read out by the overall control unit 211, and the data is expanded and the VRAM 210, 22
0 is transferred. Thereby, the LCD 10 or the EVF 20
Displays the image with the largest frame number, that is, the most recently captured image. In this state, operating the button U displays an image with a large frame number, and pressing the button D displays an image with a small frame number.

<2. Schematic operation of digital camera> FIG.
FIG. 3 is a diagram showing a schematic flow of an operation of the digital camera 1 in a photographing mode. In the photographing mode, an image is periodically acquired by the CCD 303 while no operation is performed, and is stored in the image memory 209. The image data in the image memory 209 is transferred to the VRAM 210 and displayed on the LCD 10 (Step S11). Thereby, the subject image is displayed on the LCD 10 in real time.

When the shutter button 9 is half-pressed (step S12), AF control is performed by the overall control unit 211 so that the contrast of the image in the image memory 209 is maximized as described above (step S12). S13). Note that, more accurately, the AF control is performed while obtaining the image a plurality of times.

Next, the overall control unit 211 sequentially performs a process of determining the vertical direction of the subject in the image (hereinafter, referred to as “top / bottom determination”), a photometric operation, and a colorimetric operation (steps S 14 to S 16). Exposure time, aperture value and W
The gain setting of the B circuit is performed. Steps S14 to S1
Details of 6 will be described later.

Thereafter, the state shifts to a state of waiting for the shutter button 9 to be fully pressed (steps S17 and S18). When the shutter button 9 is fully pressed, the main photographing is executed, and the acquired image is displayed on the LCD 10. (Step S1
9). In other words, CC is determined by the set exposure time and aperture value.
An image is acquired by D303, and WB correction is performed with the set gain.

When the actual photographing is performed, the user is inquired whether or not to save the image obtained in the actual photographing, and when the save is selected, the image is stored in the memory card 8 (step S20, step S20). S21).

When the shutter button 9 is not fully pressed from the half-pressed state (step S18), when the image obtained in the main shooting is not stored (step S20), and after the image obtained by the main shooting is stored , Step S11
Then, the live view display is performed.

<3. Exposure Control and WB Control> FIG. 6 is a block diagram showing a configuration relating to photometric calculation and colorimetric calculation for exposure control and WB control. In FIG.
The CPU 261 and the ROM 262 are included in the overall control unit 211, and the other configuration is the same as that shown in FIG. FIG.
As shown in (2), in the digital camera 1, the processes related to photometry and colorimetry (steps S14 to S16) are performed by the CPU 261.
Is implemented in software by performing arithmetic processing according to a program 262a in the ROM 262. When the digital camera 1 is manufactured, the program 262a
The program may be stored in the M262, or the program may be transferred from the memory card 8 to the ROM 262 using the memory card 8 as a recording medium on which the program is recorded. In addition, a program may be transferred from the CD-ROM 226 to the digital camera 1 via the computer 225 as shown in FIG.

FIG. 7 is a block diagram showing the functions of the CPU 261 when performing the photometric calculation and the colorimetric calculation together with the peripheral configuration. In FIG. 7, the top / bottom determination unit 265, the photometry calculation unit 266, and the colorimetry calculation unit 267 correspond to the functions realized by the CPU 261.

The image data is input from the image memory 209 to the top / bottom discrimination unit 265, and the top / bottom direction (hereinafter, abbreviated as “top / bottom direction”) of the subject in the image is discriminated. For example, when the whole body of a person in a standing posture is photographed under normal lighting, the top and bottom directions are determined with the upper body side and the lower body side of the person as the upper side and the lower side of the subject image, respectively, regardless of the orientation of the digital camera 1. Is done.

The result of the top / bottom discrimination is input to the photometry calculation unit 266 and the colorimetry calculation unit 267. The photometric calculation unit 266 performs a photometric calculation in consideration of the determined vertical direction,
The exposure time and aperture value of the CCD 303 are obtained. The exposure time is given to the timing control circuit 202, and the aperture value is given to the aperture control driver 306. Colorimetric calculation unit 2
Also in 67, the colorimetric calculation considering the vertical direction is performed,
The gain for each of the R, G, and B colors is determined. The obtained gain is sent to the WB circuit 207, and the WB circuit 207
Is updated.

With the above configuration, it is possible to obtain an appropriate image in the actual photographing taking into account the vertical direction of the subject in the image.

FIG. 8 is a flowchart showing the details of the top / bottom discrimination (step S14) by the top / bottom discrimination unit 265. In the top / bottom discrimination, first, a plurality of areas for the top / bottom discrimination (hereinafter, referred to as “top and bottom”
This is called a “determination area”. Is set (step S1).
41). FIG. 9 is a diagram showing a setting form of the plurality of determination areas 411 to 414. The direction 501 is a direction from the lower part to the upper part of the digital camera 1.

As shown in FIG. 9, the pixel arrangement in the image (that is, the pixel arrangement of the CCD 303) is previously 20 × 14.
(= 280) small blocks 401. For example, if the number of pixels of the CCD 303 is 2100 × 140
In the case of 0, the number of pixels in one block is 105 × 100. The upper, lower, left and right block groups composed of 10 × 7 blocks 401 are respectively used for the determination areas 411 to 4.
It is set as 14.

Next, the luminance of each of the determination areas 411 to 414 is obtained (the average luminance of each area may be obtained.
The sum of the brightness of each pixel in the region or the sum of the average brightness of each block may simply be obtained. ) (Step S14)
2). When the brightness of each area is obtained, the determination area 41
1,412, the sum L12 of the luminances, the determination areas 412, 41
3, the area corresponding to the largest one of the sum L23 of the luminances of L3, the sum L34 of the luminances of the determination areas 413 and 414, and the sum L41 of the luminances of the determination areas 414 and 411 is specified, and the specified area Is determined to be above the subject in the image (step S143).

That is, when the value L12 is the largest, it is determined that the direction 502a shown in FIG. 9 is upward (that is, the top side in the vertical direction), and when the values L23, L34, and L41 are the largest, Direction 502b, 502
It is determined that c and 502d are on the upper side. Then, two regions other than the upper region are determined to be lower regions of the subject in the image.

When the orientation of the image is determined based on the luminance of the pixel, if the illumination environment of the subject is special (for example, when the illumination is performed from the feet of a person), the appropriate orientation determination is not performed. Therefore, it can be said that the above-described top / bottom discrimination is, to be precise, a process of estimating the vertical direction of the subject in the image. Note that it is difficult to reliably determine the upside-down direction using any upside-down determination method.
It can be said that the process of determining the vertical direction is the process of estimating the vertical direction.

In Japanese Patent Laid-Open No. 2000-184271, the top and bottom discrimination is performed using only the periphery of the image, but the digital camera 1 performs the top and bottom discrimination using not only the periphery but also the center of the image. . Thus, even when the main subject is illuminated from above with the background being dark, appropriate top / bottom discrimination is realized based on the luminance distribution on the main subject.

FIG. 10 shows a photometry operation unit 266 after the top and bottom discrimination.
9 is a flowchart showing details of photometric calculation (step S15) executed by (1). In the photometric calculation, first, a plurality of areas for photometric calculation (hereinafter, referred to as “photometric areas”) are set in the image according to the up-down direction (step S151).

FIG. 11 and FIG. 12 are diagrams showing a setting mode of a plurality of photometric areas 421 to 425. FIG. 11, a direction 502 indicates the vertical direction (vertical direction) of the subject in the image, and the photometric areas 421 to 421 when the vertical direction (direction 501) of the digital camera 1 matches the vertical direction 502 of the image. 425 is shown. Regions 421-4
23 is set as a rectangular area long in the vertical direction 502 at the center of the image, an area 423 surrounds the area 422,
22 surrounds the region 421. The regions 424 and 425 are respectively set outside and above the region 423 at the upper and lower positions with respect to the vertical direction 502, and do not include the outermost block 401.

FIG. 12 is a diagram showing a setting form of a plurality of photometric areas 421 to 425 when the vertical direction 502 is perpendicular to the vertical direction 501 of the digital camera 1.
Also in FIG. 12, the regions 421 to 423 are set as rectangular regions long in the vertical direction 502 at the center of the image, the region 423 surrounds the region 422, and the region 422 surrounds the region 421. Also, the regions 424 and 425 are respectively the region 423
Are set on the upper and lower sides with reference to the up-down direction 502, and these areas are set in the outermost block 4
01 is not included.

As described above, in the digital camera 1, since the setting form of the photometric areas 421 to 425 is changed according to the top and bottom directions, the accuracy of the photometric calculation described below is improved.

When a plurality of photometric areas 421 to 425 are set, an average value of pixel luminance (hereinafter, referred to as “block luminance”) is obtained for each block 401 (step S152). Then, a weighted average of the luminance of each block 401 is obtained as a photometric evaluation value (step S15).
3). That is, the photometric evaluation value is obtained by dividing the weighted sum obtained by summing the values obtained by multiplying the luminance of each block 401 by the weighting coefficient by the total number of blocks. In the control of the digital camera 1 based on photometry, a weighted sum of the luminance of each block 401 may be obtained as a photometric evaluation value, and parameters for evaluating the photometric evaluation value may be adjusted. Also, the luminance of each block does not need to be calculated as the average luminance,
The sum of the luminance of the pixels may be used as the luminance of the block. That is, in the photometric calculation, the weighted sum of the luminances of the pixels is obtained using the weighting coefficient determined based on the photometric area, and the photometric evaluation value is a value corresponding to the weighted sum.

The weighting coefficients are “64” for the block of the area 421, “32” for the block of the area 422, “16” for the block of the area 423, “4” for the block of the area 424, and area 425. Is set to “1”. Also, “0” is set substantially for the outermost block of the image.

By setting the weighting coefficient as described above, the photometry area 421 substantially at the center of the image included in the plurality of photometry areas is set.
423 are long areas in the vertical direction and are mainly measured, so that photometry suitable for photographing with a person as a main subject is realized.

Since the lower part is less important than the upper part in the peripheral part of the image, the weighting coefficient corresponding to the upper color measuring area 424 of the image specified by the top and bottom direction is the lower color measuring area 425 of the image. Is set to be larger than the weighting coefficient corresponding to.

Since the outermost periphery of an image can be regarded as having no significance in photographing, it is not used in photometric calculation. Therefore, in the top / bottom discrimination, the entire image is set as a calculation target, but in the photometry calculation, a portion excluding the outer peripheral portion of the image is set as a calculation target, and appropriate top / bottom discrimination and photometry calculation are realized. For example, when a light source exists at a corner of an image, the top and bottom determination is performed in consideration of the position of the light source in the top and bottom determination, but the influence of the light source is suppressed in the photometric calculation.

When the photometric evaluation value is obtained, the photometric evaluation value is compared with various parameters, and the exposure time and aperture value of the CCD 303 are obtained (step S154). For example, if the photometric evaluation value exceeds a target level to be compared by a predetermined amount or more, the exposure time is set short,
If the amount falls below the predetermined amount, the exposure time is set to be long. Also, the aperture value is determined so that the exposure of the CCD 303 is performed more appropriately. After that, the photometric calculation unit 26
From 6 the signal indicating the exposure time is sent to the timing control circuit 202.
To the aperture control driver 3
06 (step S155).

In the digital camera 1, the photometric area 4
The number of the regions 21 to 425 is made larger than the number of the regions for determination 411 to 414, and the shape of the photometric region is made to be more complicated than the shape of the region for determination (that is, there are many vertices). Although it is sufficient to simply estimate the top and bottom from the entire image, the photometry calculation needs to be performed in detail, and thus such area setting realizes a calculation process suitable for the top and bottom judgment and the photometry calculation. You.

FIG. 13 shows each block 40 when the top and bottom are determined.
FIG. 7 is a diagram illustrating a state in which a luminance of 1 is obtained. FIG.
As shown in the figure, after the luminance of each block 401 is obtained at the time of the top / bottom discrimination, a plurality of block groups 4121 to 4101 are used in the discrimination area 412 as illustrated by different parallel oblique lines.
4125, the sum of the luminance of the block 401 (hereinafter, referred to as
This is called “brightness of a block group”. ) Is required. After that, the total luminance of the block groups 4121 to 4125 is obtained, and then the luminance of the determination area 412 is calculated. here,
The boundaries of the block groups 4121 to 4125 are set based on the boundaries of the photometric area shown in FIG. Thus, in the photometric calculation, the photometric evaluation value is obtained by diverting the luminance of the block group, instead of obtaining the photometric evaluation value from the luminance of each block 401.

That is, a plurality of block groups (hereinafter, referred to as "auxiliary areas") are set using the boundaries of the plurality of determination areas and the boundaries of the plurality of photometric areas, and calculations are performed on the auxiliary areas. After that, the calculation for the determination area is performed, and in the photometric calculation, the calculation result for the auxiliary area is used. As a result, the speed of the photometric calculation can be increased. Also,
The top and bottom determination and the photometric calculation can be easily performed on the same image without reacquiring the image, and the speed of the photometric calculation can be further increased.

In order to increase the speed of photometric calculation by the above method, it is preferable to reduce the number of auxiliary areas. The number of auxiliary areas increases as the degree of mismatch between the boundary of the determination area and the boundary of the photometric area increases. Therefore, in the digital camera 1, the boundary of the discrimination area and the boundary of the photometry area in the portion indicated by reference numeral 428 in FIGS. 11 and 12 coincide with each other, and the number of the block groups 4121 to 4125 shown in FIG. Care is taken to reduce it. That is, the speed of the photometric calculation can be increased by at least partially matching the boundary of the determination region with the boundary of the photometric region. In the digital camera 1, by setting a plurality of discrimination areas and a plurality of photometry areas with reference to the block 401, the boundary of the discrimination area and the border of the photometry area can be easily matched at least in part. Have been able to.

FIG. 14 is a flowchart showing details of the colorimetry calculation (step S16) executed by the colorimetry calculation section 267. Also in the colorimetric calculation, first, a plurality of areas for colorimetric calculation (hereinafter, referred to as “colorimetric areas”) are set in the image according to the up-down direction (step S161). FIG. 15 and FIG. 16 are views showing a setting form of a plurality of color measurement areas 431 to 434. 15 and 16, a direction 501 indicates the vertical direction of the digital camera 1, and
Numeral 2 indicates the determined vertical direction. As shown in FIGS. 15 and 16, the plurality of colorimetric regions 431 to 434 are set to have shapes that are long in a direction perpendicular to the top and bottom directions.

Next, in each block 401, the average value of the R, G, and B values for each pixel (hereinafter, “R, G,
G, B value ". ) Is obtained (step S16)
2) The respective weighted averages of the R, G, and B values of the block 401 are obtained as the colorimetric evaluation values for R, G, and B (step S163). That is, the colorimetric evaluation value R for R is obtained by dividing the weighted sum obtained by summing the values obtained by multiplying the R value of each block 401 by the weighting coefficient by the total number of blocks.
s is required. Similarly, the colorimetric evaluation values Gs and Bs for G and B are obtained.

The weighted sum of the R, G, and B values of each block 401 is obtained as a colorimetric evaluation value, and WB control is performed by adjusting parameters for evaluating the colorimetric evaluation value. You may. That is, a weighted sum of the R, G, and B values of each block is obtained by using a weighting coefficient determined based on a plurality of colorimetric regions in the colorimetric operation, and the colorimetric evaluation value is a value corresponding to the weighted sum. It is said.

As the weighting coefficient, “16” is set for the block of the area 431, “8” is set for the block of the area 432, “4” is set for the block of the area 433, and “1” is set for the block of the area 434. You. That is, the weight coefficient corresponding to the upper color measurement area of the image specified by the top and bottom direction is set to be larger than the weight coefficient corresponding to the lower color measurement area. By setting such weighting coefficients, the colorimetric operation is performed with emphasis on the upper side (the top side in the vertical direction) of the subject in the image.

The colorimetric evaluation values Rs, Gs, Bs are converted into new evaluation values gr, gb according to equation (1).

[0091]

(Equation 1)

Then, based on the evaluation values gr and gb, a white balance control value (hereinafter referred to as “WB control value”).
grw and gbw are obtained (step S164). FIG. 17 is a diagram for explaining a process of obtaining the WB control values grw and gbw.

In FIG. 17, a point 510 is located at coordinates (gr, gb) in the xy coordinate system. Coordinates (gr,
As the value of the x coordinate of gb) is larger and the value of the y coordinate is smaller, Gs / Rs becomes larger than Gs / Bs, so that the original image is bluish. Conversely, the smaller the value of the x-coordinate and the larger the value of the y-coordinate, the smaller the value of Gs / Rs with respect to Gs / Bs, so that the original image is reddish. Therefore, a point close to the straight line 520 extending at an angle of 45 ° from the origin is a point corresponding to an image with a proper white balance (an image of a subject illuminated by natural light).

As shown in FIG. 17, a white balance mode (hereinafter referred to as a “WB mode”) previously set at the time of photographing is set.
That. ), The areas 521, 52 are included in the xy coordinate system.
2 is set, the area 521 corresponds to the daylight mode, and the area 522 corresponds to the incandescent bulb mode. And W
The position of the point 510 is converted to the closest position in the region 521 or 522 according to the B mode. As a result, coordinate conversion is performed in consideration of the lighting environment, chromatic adaptation of human vision, and the like.

In FIG. 17, point 511 indicates the converted position of point 510 in the daylight mode, and point 512 indicates the converted position of point 510 in the incandescent bulb mode. Then, the coordinates (grw, gbw) of the converted position are used as the WB control values. When the point 510 is included in the conversion reference area, the position of the point 510 is not converted.

When the WB control values grw and gbw are obtained, the value R used for the WB control is calculated by the operation shown in Expression 2.
w, Gw, and Bw are obtained. And the colorimetric evaluation value R
so that s, Gs, and Bs become values Rw, Gw, and Bw,
R, G, and B gain setting values are obtained. The obtained set value is transferred to the WB circuit 207, and the gain setting of the white balance is updated (step S165). As a result, WB control according to the WB mode at the time of actual photographing is performed.

[0097]

(Equation 2)

As described above, in the colorimetric calculation of the digital camera 1, since the colorimetric area is set in accordance with the determined top-down direction, the colorimetric calculation according to the direction of the subject in the image is performed. WB control is realized.

Further, when a colorimetric evaluation value is obtained, a predetermined weighting coefficient for each colorimetric area is used, so that arithmetic processing can be performed at high speed. Since the weighting coefficient is set larger in the colorimetric area above the subject in the image, appropriate WB control can be performed in consideration of the influence of the light source.

Note that a plurality of discrimination areas for the top and bottom discrimination,
Since the plurality of photometric areas in the photometric operation, and the setting form of the plurality of colorimetric areas in the photometric operation are different from each other,
Accuracy of top and bottom discrimination, photometry calculation and colorimetry calculation (that is,
Exposure control and WB control). In addition, the top and bottom determination, the photometry calculation and the colorimetry calculation are performed on the same image in the image memory 209, and these calculation processes are performed quickly without re-capturing the image.

<4. Modifications> Although the digital camera 1 according to one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible.

For example, in the above embodiment, the direction of the top and bottom is determined from the image, and the photometric calculation and the colorimetry calculation according to the top and bottom direction are performed. Good. FIG. 18 is a longitudinal sectional view illustrating the structure of the mercury sensor 600 for performing the top / bottom discrimination.

In FIG. 18, the four corners of the outer shell of the mercury sensor 600 are electrodes 601 to 604, and electrodes 611 are provided inside. Mercury 612 is stored between the outer shell and the inner electrode 611. In the state shown in FIG. 18, the electrodes 602 and 611 are energized by mercury. When the mercury sensor 600 is provided in a digital camera, the storage position of the internal mercury 612 changes according to the posture of the digital camera.
04 is energized, and the posture of the digital camera can be detected. Thereby, the vertical direction of the subject in the image can be determined. The top and bottom determination may be performed by another type of displacement sensor, acceleration sensor, or the like.

When the orientation is determined based on the image,
The top and bottom determination does not necessarily have to be performed based on the pixel value or the luminance of the block. For example, the top and bottom determination may be performed based on the G value of a pixel that can be regarded as luminance. That is, the top and bottom determination can be performed based on the pixel value of the image.

In the digital camera 1, various regions are set by grouping the blocks 401. However, the regions may be set in units of pixels without using blocks.

Similarly, obtaining the weighted sum of the luminance for each block in the photometric operation is substantially equivalent to obtaining the weighted sum of the luminance for each pixel, and even if the photometric operation is performed without using the block as a unit. Good. Similarly, in the colorimetric calculation, obtaining the R, G, B values for each block is based on the R, G,
This is equivalent to obtaining a weighted sum of B values, and the calculation may be performed in units of pixels.

In the digital camera 1, the WB control is performed by the top / bottom discriminator 265, the colorimetric calculator 267, and the WB circuit 2.
07, the function equivalent to the WB circuit 207 may be performed before the A / D conversion (for example, in the signal processing circuit 313). Further, the WB control may be executed as a WB correction for the acquired image.

The gain setting of the WB control, and the exposure time and aperture value of the exposure control do not have to be reset for each photographing, but may be reset only when they are shifted by a predetermined amount or more.

Further, the setting mode of the determination area, the photometric area and the colorimetric area in the above embodiment is merely an example, and other setting modes may be adopted. Further, the setting form of any of these areas may be the same as the setting form of other types of areas.

In the above embodiment, the top and bottom discrimination, the photometric operation and the colorimetric operation are realized by software when the CPU 261 executes the program 262a, but all or a part of these components are provided by a dedicated electric circuit. It may be realized.

In the above embodiment, a digital still camera for obtaining a still image has been described as an example. However, various techniques in the above embodiment are applied to various digital imaging devices including a video camera for obtaining a moving image. can do.

[0112]

According to the first to seventh aspects of the present invention, it is possible to perform appropriate white balance control in consideration of the orientation of a subject in an image.

According to the second aspect of the present invention, the vertical direction of a subject in an image can be determined from the image.

According to the third and fourth aspects of the present invention, it is possible to obtain a colorimetric evaluation value in consideration of the vertical direction of a subject in an image.

According to the fifth aspect of the present invention, it is possible to control the white balance in consideration of the influence of the light source.

Further, according to the present invention, it is possible to appropriately determine the vertical direction of the subject in the image and control the white balance.

According to the eighth to fourteenth aspects of the present invention, the determination of the vertical direction of the subject in the image and the photometric calculation can be appropriately performed.

According to the eleventh aspect of the present invention, the determination of the vertical direction of a subject in an image and the setting of an area suitable for photometric calculation are performed.

According to the twelfth aspect of the present invention, it is possible to enhance the accuracy of discrimination of the subject in the image in the vertical direction, the photometric calculation, and the control of the white balance.

Further, according to the thirteenth aspect, it is not necessary to reacquire an image.

According to the fifteenth to seventeenth aspects, the photometric calculation can be performed at high speed.

According to the sixteenth aspect of the present invention, it is possible to perform a photometric calculation in consideration of the influence of illumination.

According to the eighteenth and nineteenth aspects, photometry suitable for photographing with a person as a main subject is performed.

[Brief description of the drawings]

FIG. 1 is a plan view of a digital camera.

FIG. 2 is a longitudinal sectional view of the digital camera.

FIG. 3 is a rear view of the digital camera.

FIG. 4 is a block diagram illustrating a configuration of a digital camera.

FIG. 5 is a flowchart showing an outline of the operation of the digital camera.

FIG. 6 is a block diagram illustrating a configuration related to a photometric operation and a colorimetric operation.

FIG. 7 is a block diagram illustrating a functional configuration related to photometric calculation and colorimetric calculation.

FIG. 8 is a flowchart showing the operation of top and bottom determination.

FIG. 9 is a diagram illustrating a discrimination area.

FIG. 10 is a flowchart showing the operation of the photometric calculation.

FIG. 11 is a diagram exemplifying a photometry area.

FIG. 12 is a diagram illustrating a photometry area.

FIG. 13 is a diagram exemplifying a block group at the time of calculation;

FIG. 14 is a flowchart showing an operation of a colorimetric calculation.

FIG. 15 is a diagram illustrating a colorimetric area.

FIG. 16 is a diagram illustrating a colorimetric area.

FIG. 17 is a diagram illustrating a colorimetric calculation.

FIG. 18 is a longitudinal sectional view of the mercury sensor.

[Explanation of symbols]

 Reference Signs List 1 digital camera 8 memory card 207 WB circuit 261 CPU 262 ROM 262a program 265 top / bottom discrimination unit 266 photometry operation unit 276 colorimetry operation unit 303 CCD 401 block 411-414 discrimination area 421-425 photometry area 431-434 for colorimetry Area 502, 502a to 502d Direction S11, S14 to S16 Step

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H04N 101: 00 H04N 101: 00 F term (Reference) 2H002 CC00 DB14 DB17 DB25 HA04 JA07 2H054 AA01 5C022 AB03 AB15 AB17 AB22 AB66 AC03 AC31 AC42 AC54 AC56 AC69 AC74 5C065 AA03 BB02 BB12 BB48 CC01 DD02 GG12 GG15 GG18 GG27 GG32 5C066 AA01 EA14 EC05 GA01 KE02 KE05 KE07 KM02

Claims (19)

[Claims] 1. A digital imaging apparatus, comprising: imaging means for acquiring an image of a subject as digital data; determining means for determining the vertical direction of the subject in the image; and controlling white balance according to the vertical direction. A digital imaging device comprising: 2. The digital imaging apparatus according to claim 1, wherein the determination unit determines the up-down direction based on a plurality of determination areas set in the image. apparatus. 3. The digital imaging device according to claim 2, wherein the control unit measures R, G, and B based on a plurality of colorimetric regions set in the image while following the vertical direction. A digital imaging device, wherein a color evaluation value is obtained, and a white balance is controlled using the colorimetric evaluation value. 4. The digital imaging device according to claim 3, wherein the control unit calculates a weighted sum of pixel values for each of R, G, and B of the image based on the plurality of colorimetric regions. A digital imaging apparatus for calculating the colorimetric evaluation value using the weighted sum. 5. The digital imaging apparatus according to claim 4, wherein when the control means calculates the weighted sum, a weight corresponding to a colorimetric area in an upper part of the image specified by the up-down direction. A digital imaging device, wherein a coefficient is set to be larger than a weighting coefficient corresponding to a colorimetric area below the image. 6. The digital imaging apparatus according to claim 3, wherein the plurality of determination areas and the plurality of colorimetric areas are set differently. apparatus. 7. A recording medium on which a program for controlling a digital imaging device is recorded, wherein the execution of the program by the digital imaging device includes: obtaining a subject image as digital data by the digital imaging device; A recording medium for executing a step of determining a vertical direction of the subject in an image and a step of controlling a white balance while following the vertical direction. 8. A digital imaging apparatus, comprising: imaging means for acquiring an image of a subject as digital data; and performing a calculation on the entire image as a calculation target to determine a vertical direction of the subject in the image. A digital imaging device comprising: a photometric unit that performs photometric computation on a portion except for a peripheral edge of the image while following the vertical direction. 9. A recording medium on which a program for controlling a digital imaging device is recorded, wherein the execution of the program by the digital imaging device includes: acquiring a subject image as digital data in the digital imaging device; Performing a calculation on the entire image as a calculation target, determining the vertical direction of the subject in the image, and performing a photometric calculation on the calculation target for a portion excluding a peripheral portion of the image while following the vertical direction, Recording medium. 10. A digital imaging device, comprising: imaging means for acquiring an image of a subject as digital data; and determining a vertical direction of the subject in the image based on a plurality of determination areas set in the image. A digital imaging device comprising: a determination unit that performs a photometric calculation based on a plurality of photometric regions that are different in a setting form from the plurality of determination regions while following the vertical direction. 11. The digital imaging device according to claim 10, wherein the number of the plurality of photometric areas is larger than the number of the plurality of determination areas. 12. The digital imaging device according to claim 10, wherein a white color is set based on a plurality of colorimetric regions having different setting modes from each of the plurality of determination regions and the plurality of photometric regions. A digital imaging device further comprising control means for controlling balance. 13. The digital imaging device according to claim 10, wherein the determination unit and the photometry unit perform processing on the same image acquired by the imaging unit. Digital imaging device characterized by the following. 14. A recording medium recording a program for controlling a digital imaging device, wherein the execution of the program by the digital imaging device includes: acquiring a subject image as digital data in the digital imaging device; A step of determining the vertical direction of the subject in the image based on a plurality of determination areas set in the image; and a plurality of photometric areas different in the setting form from the plurality of determination areas while following the up-down direction Performing a photometric operation on the basis of (i). 15. A digital imaging device, comprising: imaging means for acquiring an image of a subject as digital data; and Discriminating means for discriminating, and photometric means for performing photometric calculation based on a plurality of photometric areas set in the image while following the up-down direction, and The image in which the photometry area is set is the same, and the image is divided into a plurality of small blocks, and the plurality of determination areas and the plurality of photometry areas are set based on the small blocks, and A boundary between a plurality of discrimination areas and a boundary between the plurality of photometry areas at least partially coincide with each other, and the discrimination in the vertical direction and the photometry calculation are performed on the plurality of small blocks. A digital imaging device, which is performed based on a value derived from the digital imaging device. 16. The digital imaging device according to claim 15, wherein in the photometric calculation, a weighted sum of the luminance of each block is obtained based on the plurality of photometric regions, and the weighted sum is obtained. A digital imaging apparatus, wherein a weighting coefficient corresponding to a photometric area at an upper part of the image specified by the vertical direction is set to be larger than a weighting coefficient of a photometric area corresponding to a lower part of the image. 17. A recording medium recording a program for controlling a digital imaging device, wherein the execution of the program by the digital imaging device includes: acquiring a subject image as digital data in the digital imaging device; Determining the vertical direction of the subject in the image based on a plurality of determination areas set in the image; and performing a photometric calculation based on the plurality of photometric areas set in the image while following the vertical direction. And a step of performing the step of performing, wherein a boundary between the plurality of determination regions and a boundary between the plurality of photometry regions at least partially coincide with each other. 18. A digital imaging device, comprising: imaging means for acquiring an image of a subject as digital data; determining means for determining the vertical direction of the subject in the image; and the vertical direction substantially at the center of the image. A photometric unit for performing photometric calculation based on a plurality of photometric areas including a long area. 19. A recording medium storing a program for controlling a digital imaging device, wherein the execution of the program by the digital imaging device includes: acquiring a subject image as digital data in the digital imaging device; Determining the vertical direction of the subject in the image, and performing a photometric operation based on a plurality of photometric areas including a vertically long area at substantially the center of the image,
Recording medium.