JPH11355709A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a digital camera that can record image data with high quality without missing a shutter chance. SOLUTION: A total control section of the digital camera executes image fetch processing as follows: in the step S1201, whether or not display for white balance setting is ON is discriminates and in the case it is ON (Yes), since this means photographing with shutter priority, it is regarded that white balance is possibly unbalanced and the processing after the step S1204 is performed. Then till k=6 is discriminated in the step S1207, the processing of the steps S1206-S1208 is repeated. Thus, the processing of the steps S1206-S1208 is repeated in total six times. As a result, even when a shutter button reaches an S2 state (a fully depressed state) in the middle of white balance setting, 6 image data whose white balance is corrected are stored in image memories 209-1-209-6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera, and more particularly, to a digital camera having a circuit for performing image correction such as a white balance circuit.

[0002]

2. Description of the Related Art In recent years, with the development of semiconductor technology, a so-called digital camera that converts a photographic scene into an electric signal by an image pickup device, converts the converted electric signal into digital image information, and processes and records the image has been developed. It is in the process of development.

Since the latitude of an image pickup device is generally narrower than that of a silver halide film, a slight exposure error affects the image quality. In addition, since a scene under specific illumination such as a fluorescent light is captured as it is, unless the white balance processing of the image data is performed, an image having an improper color balance is recorded. Therefore, provisional exposure is performed before main exposure, image processing parameters including the white balance processing are set, and image correction is performed on image data at the time of main exposure using the set values. .

[0004]

However, if an attempt is made to increase the accuracy of such image correction, it takes a long time for the processing, and there is a possibility that a photo opportunity is missed.

[0005] Therefore, there is a need for a digital camera having a system in which an appropriate image correction is performed without a photographer missing a photo opportunity. Further, there is a demand for a digital camera that can show the result to a photographer even if appropriate image correction is not performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a digital camera capable of recording high-quality image data without missing a photo opportunity.

[0007]

According to a first aspect of the present invention, there is provided a digital camera, comprising: an imaging unit configured to convert an optical image of a subject into an image signal; and a correction condition set value set in accordance with the image signal. Image correcting means for correcting the image signal based on the image signal and outputting a corrected image signal; image storing means for storing the corrected image signal; and operation of the imaging means, the image correcting means and the image storing means. And an overall control unit for controlling, the overall control unit performs an update process of the correction condition set value at the time of imaging preparation, and enters an imaging execution state during the update process of the correction condition set value,
From the captured image image correcting unit, the corrected image signal obtained by performing the image correction using the existing correction condition value as the correction condition setting value is continuously output a plurality of times, and the output plurality of corrected image signals are output. Each is stored in the image storage means.

The digital camera according to claim 2 is
A recording medium capable of recording the corrected image signal under the control of the overall control unit, wherein the overall control unit evaluates the plurality of corrected image signals stored in the image storage unit by a predetermined evaluation method. An evaluation function for evaluating and determining a corrected image signal having the best evaluation among the plurality of corrected image signals, wherein the overall control unit captures an image during an update process of the correction condition set value. When it is running,
The corrected image signal having the best evaluation is recorded on the recording medium.

According to a third aspect of the present invention, there is provided a digital camera, comprising: an image pickup means for converting an optical image of a subject into an image signal; and an image signal converting means for converting the image signal based on a correction condition set value set in accordance with the image signal. Image correcting means for correcting and outputting a corrected image signal, notifying means capable of notifying of a warning state, and overall control for controlling operations of the image pickup means, the image correcting means and the notifying means Means, wherein the overall control means has an evaluation function of determining whether the corrected image signal satisfies a predetermined criterion, and the overall control means sets the correction condition setting value at the time of preparation for imaging. When the imaging execution state is entered during the update processing of the correction condition set value, the image correction unit performs image correction using an existing correction condition value as the correction condition set value. Tadashizumi to output an image signal, when the corrected image signal is evaluated and does not satisfy the predetermined reference, thereby notifying that the warning state to said notification means.

The digital camera according to claim 4 is
The apparatus further comprises a recording medium on which the corrected image signal can be recorded, wherein the overall control unit is configured to execute the corrected image irrespective of an evaluation result by the evaluation function when the imaging execution state is entered during the correction condition setting value update processing A signal is recorded on the recording medium.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS << Example of Basic Structure of Digital Camera to Which the Present Invention is Applied >> FIGS. 1 to 3 are diagrams showing the basic structure of a digital camera according to the present invention, and FIG. 2 corresponds to a rear view, and FIG. 3 corresponds to a bottom view. These figures do not always follow the triangular projection,
The main purpose is to conceptually illustrate the basic structure of a digital camera.

As shown in these figures, the digital camera 1 has a structure roughly divided into a substantially rectangular parallelepiped camera main body 2 and a substantially cylindrical imaging section 3, and the imaging section 3 is supported. The camera body 2 is detachably attached to the right side surface in FIG. 1 via the portion 19, and is rotatably mounted in a plane parallel to the right side surface.

The image pickup section 3 has an image pickup system comprising a macro zoom lens 301 as an image pickup lens and a photoelectric conversion element such as a CCD (Charge Coupled Device), and photoelectrically converts an optical image of a subject with each pixel of the CCD. This is a component for converting the image into an image constituted by the obtained charge signals and capturing the image.

A macro zoom lens 301 is provided inside the image pickup section 3, and a CCD color area sensor (hereinafter, simply referred to as “CCD”; a CCD color area sensor) is provided at an appropriate position behind the macro zoom lens 301. An imaging circuit is provided which is hidden on the back side and is not shown in FIGS. 1 to 3). In addition, a dimming sensor 305 that receives the reflected light of the flash light from the subject is provided at an appropriate position of the imaging unit 3.

On the other hand, the camera main body 2 has an LCD display section 10 comprising a backlit LCD (Liquid Crystal Display), and a mounting section 17 for a memory card 8 as a recording medium.
And a connection terminal 13 to which a personal computer is externally connected. After subjecting the image signal captured by the imaging section 3 to predetermined signal processing, display on the LCD display section 10 and recording on the memory card 8 And processing such as transfer to a personal computer.

Hereinafter, the camera body 2 will be described in detail.
As shown in FIG. 3, the camera main unit 2 includes a card loading unit 17 for loading a memory card 8 for storing a captured image as a recorded image, and a battery loading unit for loading, for example, four AA batteries so as to be connected in series. 18 are built in. The digital camera 1 is driven by a power supply battery formed by serially connecting four dry batteries loaded in the battery loading unit 18 except for an RTC 219 described later. When the memory card 8 and the power supply battery are attached and detached, the clamshell type lid 15 provided on the bottom face is opened and closed. Also power on
/ OFF is performed by a power switch PS provided on the back of the camera body 2.

As shown in FIG. 1, on the front surface of the camera body 2, a grip 4 is provided at an appropriate position on the left side, and a built-in flash 5 is provided at an appropriate position on the upper right. A connection terminal 13 is provided on the right side of the camera body so that a computer can be connected from outside the digital camera 1.

Further, as shown in FIG.
An LCD display unit 10 is provided at an appropriate position on the left side of the rear surface of the LCD 10. An FL mode (flash) setting switch 11 is provided above the LCD display unit 10 on the left side, and switches the light emission mode of the built-in flash 5. As the light emission mode, for example, "automatic light emission mode" in which light emission / non-light emission of the built-in flash 5 is automatically controlled according to subject brightness
In addition, there are a "forced light emission mode" in which the built-in flash 5 is forcibly emitted regardless of the subject brightness, and a "light emission prohibited mode" in which the built-in flash 5 is not forcibly emitted regardless of the subject brightness. The mode is FL
Each time the mode setting switch 11 is pressed, the mode is switched and set in a cyclic manner.

Further, a slide-type photographing / reproduction mode setting switch 14 having two contacts is provided above the right side of the LCD display section 10 to switch between a "photographing mode" and a "reproduction mode". The shooting mode is a mode for shooting a subject, and the LCD display unit 10 performs monitor display of the subject (corresponding to a viewfinder function). The reproduction mode is a mode in which an image recorded on the memory card 8 is reproduced and displayed on the LCD display unit 10. For example, sliding to the right sets the playback mode, and sliding to the left sets the shooting mode.

A slide type compression ratio changeover switch 12 is provided below the LCD display unit 10 on the left side, and selects a compression ratio K of image data to be stored in the memory card 8. Compression rate setting slide switch 12
Thus, two types of compression ratios K of 1/8 and 1/20 can be selected and set. For example, sliding the compression ratio setting slide switch 12 to the right sets the compression ratio K = 1/8, and sliding to the left sets the compression ratio K = 1/20. In the present embodiment, two types of compression ratios K can be selectively set. However, three or more types of compression ratios K may be selectively set.

Further, the compression ratio setting slide switch 12
A liquid crystal display slide switch 16 for turning on / off the display of the LCD display unit 10 is provided on the right side of. By turning off the liquid crystal display slide switch 16, the display on the LCD display section 10 is stopped, and the consumption of the battery can be minimized.

In addition, an UP switch 6 and a DOWN switch 7 for frame advance are provided substantially at the center of the upper surface of the camera body 2, and these switches are used to convert a recorded image already stored in the memory card 8 into a recorded image. Playback is performed in the order of the frame numbers assigned to each. Each time the UP switch 6 is pressed, the recorded images are sequentially updated in the order of increasing frame numbers (in the order of shooting), and
It is reproduced on the CD display unit 10. Also, DOWN switch 7
Each time is pressed, the recorded images are sequentially updated in the order of decreasing frame numbers and reproduced on the LCD display unit 10. A shutter button 9 is provided on the upper surface of the camera body 2 on the right side, and an erase switch D for erasing a recorded image stored in the memory card 8 is provided on the left side. Further, below the UP switch 6 and the DOWN switch 7, an optical viewfinder 21 such as that used in a silver halide lens shutter camera is provided.

<< Description of Functional Blocks of Digital Camera >><Functional Blocks of Imaging Unit 3> FIG. 4 is a block diagram showing the configuration of the digital camera 1 from the viewpoint of functions. In the figure, a CCD 303 converts a light image of a subject formed by a macro zoom lens 301 into R (red), G (green), B
The image signal is photoelectrically converted into an image signal of a (blue) color component (a signal composed of a signal sequence of pixel signals received by each pixel) and output.

The signal processing circuit 313 performs predetermined analog signal processing on the analog image signal obtained from the CCD 303. For example, CDS (correlated double sampling)
Processing and AGC (auto gain control) processing are performed. The former process reduces the noise of the image signal, and the latter process adjusts the level of the image signal.

The level adjustment of the image signal is performed in relation to the shutter speed. Since the aperture of the imaging unit 3 is fixed, exposure control is performed by adjusting the exposure amount of the CCD 303, that is, the charge accumulation time by the timing generator 314. However, if the subject brightness is low and the shutter speed is high, the exposure will be insufficient. To correct this, the signal processing circuit 313 adjusts the level of the image signal.

That is, when the luminance is low, the exposure control is performed by combining the shutter speed and the gain adjustment.
The level adjustment of the image signal is performed by the AG in the signal processing circuit 313.
This is performed in gain adjustment of the C circuit.

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.
As the drive control signal, for example, a timing signal of integration start / end (exposure start / end), a read control signal of a light receiving signal of each pixel (horizontal synchronization signal, vertical synchronization signal, transfer signal, etc.)
And so on.

The light control circuit 304 is a circuit for controlling the light emission amount of the built-in flash 5 in flash photography to a predetermined light emission amount set by the overall control unit 211.
In flash photography, the reflected light of the flash light from the subject is detected as the amount of light received by the light control sensor 305 at the same time as the exposure starts, and when the amount of received light reaches a predetermined light emission amount, the light control circuit 304 emits light from the FL control circuit. Stop signal STP
Is output to the flash control circuit 214 described later, and the light emission amount of the built-in flash 5 is controlled to be equal to or less than a predetermined light emission amount.

<Functional Blocks of Camera Body 2> The camera body 2 includes a built-in flash 5, an LCD display unit 10, a connection terminal 13, a card loading room 17, and a CPU to drive each unit of the digital camera 1 mutually. The overall control unit 211, the timing control circuit 20 that performs overall control in association with
2. A / D converter 205, black level correction circuit 206, white balance (WB) circuit 207, γ correction circuit 20
8, image memories 209-1 to 209-6, VRAM 21
0, an operation unit 250, a card interface 212, a communication interface 213, a flash control circuit 214, and an RTC (Real Time Clock) 219.

The A / D converter 205 is a signal processing circuit 31
3 is to convert each pixel signal of the image signal obtained from 3 into a 10-bit digital signal (captured image information). A
The / D converter 205 converts each pixel signal (analog signal) into a 10-bit digital signal based on a clock for analog-to-digital conversion from the timing control circuit 202.

The timing control circuit 202 is controlled by the general control unit 211 and generates a clock for the signal processing circuit 313, the timing generator 314, and the A / D converter 205.

The black level correction circuit 206 corrects the black level of the digital pixel signal (hereinafter simply referred to as “pixel data”) A / D converted by the A / D converter 205 to a reference black level.

The WB circuit 207 uses a level conversion table, which is a set value of a correction condition of white balance, input from the overall control unit 211, and uses a level conversion table for a black level correction circuit 206.
, The black level corrected pixel data obtained from
The white balance correction process is performed by converting the levels of the G and B color components. The conversion coefficient (gradient of the characteristic) of each color component in the level conversion table is set by the overall control unit 211 for each captured image. More specifically, the average values Rm, Gm, and Bm of the R, G, and B components of the image data in the central part and the peripheral specific area of the imaging range are calculated, and the correction coefficients Gm / Rm and Gm / Bm are calculated. Calculate, Gm / R
When m is equal to or greater than a predetermined value, the value is rounded to the upper limit value, and when m is equal to or less than the predetermined value, the value is rounded to the lower limit value. Similarly, when Gm / Bm is equal to or more than a predetermined value, the value is rounded to the upper limit value, and when Gm / Bm is equal to or less than the predetermined value, the value is rounded to the lower limit value.

In the white balance correction processing by the WB circuit 207, when the level conversion table has already been set, the above-described calculation (white balance calculation) does not take much time, and can be performed almost in real time.

However, when the level conversion table is not set, the generation of the level conversion table requires a repetitive operation for obtaining an average value.
The update interval of the live view image on the D display unit 10 (1
/ 30) It takes longer than seconds. Therefore, the live view image displayed at the time of shooting standby includes the WB described above.
The process of creating the level conversion table in the circuit 207 is canceled to display an image.

When the display on the LCD display unit 10 is in the OFF state, or when shooting with flash, W
There is no problem if the process of creating the level conversion table in the B circuit 207 is canceled and the image is displayed. LCD
When the display of the display unit 10 is in the OFF state, generation of a live view image is unnecessary, and it is practically necessary to match the live view image with the captured image during flash photography unless the flash is fired during live view. It is impossible.

However, the display on the LCD display unit 10 is turned on.
If the live view image is not reflected at all when the live view image is not reflected when the camera is in the state and flash photography is not performed, there is a problem that the color of the live view image may be different from the actual captured image.

Therefore, in the present embodiment, the following 2
Two modes are selectable. Live view mode 1: In standby for shooting, processing is performed using the most recently created level conversion table, such as when shooting last time. Live view mode 2: A level conversion table for white balance correction is created every three seconds even during standby for shooting, and a white balance correction process is performed using the newly created level conversion table to display a live view image. .

In mode 1, the live view image is displayed in real time, but there is a possibility that the color of the live view image differs from that of the actual photographed image.

In the mode 2, while the color of the live view image is likely to match the color of the actual photographed image, the live view image is processed during the relatively time-consuming white balance correction process involving the process of creating the level conversion table. Is not updated.

In this embodiment, the shutter button 9 is a two-stage push button switch that can distinguish between a half-pressed state (S1) and a pressed state (S2) as used in a silver halide camera. In the S1 state (imaging preparation), a level conversion table is created and updated, and in the S2 state (imaging execution state), white balance processing using the level conversion table is performed, and image data captured and recorded on the memory card 8 I am trying to do it.

As shown in FIG. 5, when there is a sufficient time difference between when the shutter button 9 is set to the S1 state and when the S2 state is set, the level conversion table newly created using the S1 state setting as a trigger is used. Although the white balance processing is possible, as shown in FIG. 6, when the time difference between the setting of the S1 state and the setting of the S2 state is short, or when there is almost no time difference, the shutter button 9 is set to the S2 state. Since it becomes impossible to create a new level conversion table by now, there are the following two ideas.

(1) White balance priority: While the level conversion table is being created, the S2 state of the shutter button 9 is not accepted. (2) Shutter priority: The S2 state of the shutter button 9 is accepted even while the level conversion table is being created, and image data taken after performing white balance processing based on the existing level conversion table is recorded on the memory card 8. I do.

In the case of giving priority to white balance, there is a merit that color correction can be performed more accurately, but there is a possibility that a photo opportunity is missed.

In the case of the shutter priority, the hue correction may be slightly inaccurate, but there is a merit that a photo opportunity is not missed.

Further, there are the following two methods for adopting the existing level conversion table. (2) -1: Adopt the most recently created level conversion table (first shutter priority mode). (2) -2: A level conversion table prepared in advance is selectively adopted in accordance with a determination result by an image determination unit 211e and a scene determination unit 211c described below (second shutter priority mode).

The shutter priority second mode will be described later in detail, but the image determination unit 211e determines whether the image is a natural image or a character image. , "Medium brightness normal scene", "medium brightness retrograde scene", and "high brightness scene", a total of five types of level conversion tables are prepared in advance. The selection of white balance priority or shutter priority, and the selection of the level conversion table in shutter priority differ depending on the purpose of photographing. Therefore, in the present embodiment, selection can be made as appropriate.

The above is summarized in Table 1 below.

[0049]

[Table 1]

Returning to FIG. 4, the gamma correction circuit 208 will be described. The γ correction circuit 208 corrects γ characteristics of image data. The γ correction circuit 208 has, for example, six types of γ correction tables having different γ characteristics, and performs γ correction of pixel data using a predetermined γ correction table according to a shooting scene or shooting conditions.

The image memory 209 (209-1 to 209-
6) is a memory for storing pixel data output from the gamma correction circuit 208. Image memories 209-1 to 209
-6 each have a storage capacity for one frame.
That is, each of the image memories 209-1 to 209-6 has a configuration in which the CCD 303 has n rows and m columns of pixels.
It has a storage capacity for pixel data of n × m pixels, and each pixel data is stored at a corresponding pixel position.

The digital camera according to the present embodiment is
When the shutter button 9 is in the S2 state, image data of six frames is continuously taken in, and each pixel data is temporarily stored in the image memories 209-1 to 209-6.
The processing described below is performed and stored in the memory card 8.

The VRAM 210 is a buffer memory for image data reproduced and displayed on the LCD display unit 10. VR
The AM 210 has a storage capacity for image data corresponding to the number of pixels of the LCD display unit 10.

In the photographing standby state, each image data of the image picked up by the image pickup unit 3 every 1/30 (second) is A
After undergoing predetermined signal processing by the / D converters 205 to γ correction circuit 208, the image data is stored in the image memory 209, transferred to the VRAM 210 via the overall control unit 211, and added to the image data stored in the VRAM 210. The based image is displayed on the LCD display unit 10. Therefore, the photographer can visually recognize the subject image from the image displayed on the LCD display unit 10. In the playback mode, after the image read from the memory card 8 is subjected to predetermined signal processing by the overall control unit 211, the VRAM 210
And reproduced and displayed on the LCD display unit 10.

The card I / F 212 is an interface for writing image data to the memory card 8 and reading image data. Also, the communication I / F 21
Reference numeral 3 denotes an interface compliant with, for example, the USB standard for externally connecting the personal computer 40 so that communication is possible.

The flash control circuit 214 is a circuit for controlling light emission of the built-in flash 5. The flash control circuit 214 controls the presence / absence of light emission of the built-in flash 5, the amount of light emission, the light emission timing, and the like based on the control signal of the overall control unit 211. Is controlled.

The RTC 219 is a clock circuit for managing the shooting date and time. It is driven by another power source not shown in FIGS.

The operation unit 250 includes the UP switch 6, DOWN switch 7, shutter button 9, FL mode setting switch 11, and compression ratio setting slide switch 1 described above.
2. A switch corresponding to the photographing / playback mode setting switch 14 is provided, and a request for control of each unit of the digital camera 1 is made to the overall control unit 211.

The overall control unit 211 is composed of a microcomputer, and controls the driving of each member in the image pickup unit 3 and the camera main body unit 2 in an organic manner to control the photographing operation of the digital camera 1 overall. is there.

FIG. 7 is a block diagram showing the internal configuration of the overall control unit 211. As shown in FIG.
Reference numeral 1 includes a luminance determination unit 211a for setting an exposure control value (shutter speed (SS)) and a shutter speed setting unit 211b. Brightness determination unit 211a
Is 1/3 by the CCD 303 in the shooting standby state.
The luminance of the subject is determined by calculating luminance data using an image captured every 0 (seconds).

That is, the luminance determining unit 211a divides the storage area of the image memory 209 into nine blocks by using the image data that is renewedly stored in the image memory 209, and G (green) included in each block. The luminance data representing each block is calculated by using the pixel data of the color component of (1) to determine the luminance of the subject.

The shutter speed setting section 211b sets a shutter speed (integration time of the CCD 303) based on the result of the luminance determination of the subject by the luminance determining section 211a. The shutter speed setting unit 211b has a table of shutter speed SS in which brightness and shutter speed SS are associated in advance.

The shutter speed SS is initially set to 1/128 (second) (the most frequent shutter speed) when the camera is started, and in a shooting standby state, the shutter speed setting unit 211b controls the brightness of the subject by the brightness determination unit 211a. Is changed from the initial value to the high-speed side or the low-speed side one by one in accordance with the determination result of.

The general control unit 211 has a captured image that is a normal photographed image of a landscape, a person, or the like (hereinafter, such a photographed image is referred to as a “natural image”), but is drawn on a board. It further includes an image determination unit 211e that determines whether an image such as a character or a chart is an image similar to a binary image of this type (hereinafter, an image similar to a "character image").

The image judging section 211e includes an image memory 209
A histogram of the luminance data at each pixel position is created based on the pixel data constituting the captured image stored in the storage device, and the content of the captured image is determined based on the histogram. Generally, in the case of a natural image, a histogram of luminance data of a captured image is a so-called one-peak distribution having a small deviation in luminance distribution and having one peak value. On the other hand, in the case of a character image such as a character drawn on a whiteboard, a luminance distribution is biased in a white background portion and a black character portion, and a two-peak distribution is obtained.

Therefore, the image determining unit 211e determines whether the histogram of the luminance data of the captured image has a single peak distribution,
It is determined whether the captured image is a natural image or a character image by determining whether the image has a two-peak distribution. Then, this determination result is stored in the memory 211d.

The general control unit 211 performs “low-brightness scene”, “medium-brightness normal scene”, “medium-brightness scene” in order to set appropriate shutter speed SS, perform γ correction and filtering correction (described later) according to the shooting scene. It further includes a scene determination unit 211c that determines four types of shooting scenes of a “luminance backlight scene” and a “high-luminance scene”. A “low-brightness scene” is a scene that normally requires auxiliary light using a flash, such as indoor shooting or nighttime shooting, and a “medium-brightness normal scene” is illumination light (including natural light and artificial light) for a main subject. ) Is a scene that can be photographed without auxiliary light because it is normal light and its brightness is appropriate. Also, the “medium brightness backlight scene” has an appropriate overall brightness,
Since the illumination light for the main subject is backlight, flash emission is a preferable scene, and the “high-brightness scene” is a very bright scene as a whole, for example, photographing in a sunny sea or a ski resort. The low-luminance, medium-luminance, and high-luminance scene determination is performed based on the set value of the shutter speed SS. In the middle-luminance scene, when the peripheral portion is brighter than the central portion by a predetermined value or more, it is determined to be a “medium-luminance backlight scene”. The determination result of the scene determination unit 211c is also stored in the memory 21.
1d.

The overall control unit 211 includes a filter unit 211f for performing a filtering process, a recorded image generation unit 211g for generating a thumbnail image and a compressed image, and a memory card 8 for recording the captured image. And a reproduced image generating unit 211h for generating reproduced image data for reproducing the reproduced image data on the LCD display unit 10.

The filter unit 211f includes an image memory 209
Is to correct the high-frequency component of the image to be recorded by the digital filter for the image data from the image data, thereby correcting the image quality related to the outline. The filter unit 211f calculates the compression ratio K
= 1/8 and 1/20 for each of the standard contour correction digital filters, two types of digital filters for strengthening the contour and two types of digital filters for weakening the contour with respect to the standard contour correction Are provided with a total of five types of digital filters.

The recorded image generation unit 211g is provided in the image memory 2
The image data is read from the image data 09 through the filter unit 211f to generate a thumbnail image and a compressed image to be recorded on the memory card 8. The recording image generation unit 211g reads image data for every eight pixels in both the horizontal direction and the vertical direction while scanning in the raster scanning direction from the image memory 209, and sequentially connects the memory connected via the card I / F 212. By transferring the thumbnail image to the card 8, the thumbnail image is generated and recorded on the memory card 8.

Further, the recording image generation unit 211g reads out all the pixel data from the image memory 209 via the filter unit 211f, and applies a predetermined compression process to the pixel data according to the JPEG method such as two-dimensional DCT conversion and Huffman coding. To generate image data of the compressed image, and record the compressed image data in the main image area of the memory card 8.

More specifically, the recording image generation unit 211g operates in the photographing mode by pressing the shutter button 9
When shooting is instructed by the image memory 2, the image memory 2
09 and a compressed image compressed by the JPEG method using the compression ratio K set by the compression ratio setting switch 12, and generates tag information (frame number, exposure value, shutter speed) for the captured image. ,
Compression rate K, shooting date, flash ON / OFF at shooting
The data, scene information, and information such as image determination results) are stored in the memory card 8 (see FIG. 8). Note that the shutter speed SS, scene information, and the like are fetched from the memory 211d.

As shown in FIG. 8, the memory card 8 converts the image stored by the digital camera into a compression ratio of 1/2.
0, 40 frames of images can be stored. Each frame includes a tag information part, high-resolution image data (640 × 480 pixels) compressed in JPEG format, and image data for thumbnail display (80 × 60 pixels). Pixel) is recorded. For example, each frame can be handled as an image file in the EXIF format.

<< Explanation of Control Flow >><Control Flow at Power ON> Next, a control flow for performing shutter control in the present embodiment will be described. This process is performed under the control of the overall control unit 211.

FIG. 9 is a flowchart showing a processing flow of a setting state determination processing routine which is started when the power is turned on. Referring to the figure, in step S801, based on the ON / OFF state of the liquid crystal display slide switch 16 and the ON / OFF state of the FL mode setting switch 11 in Table 1,
Perform a conditional branch according to the index LF_State shown in FIG.

That is, when LF_State = 1, the live view mode 1 is set in step S802, and then the shutter priority is set in step S803.
When LF_State = 2, the live view mode 2 is set in step S804, and white balance priority is set in step S805. LF_State =
At 3, the display on the LCD display unit 10 is in the OFF state, so that the process jumps to step S803 to set only the shutter priority. Similarly, when LF_State = 4, the process jumps to step S805 to set only the white balance priority.

<Setting Change Flow> Whether the shutter timing is the shutter priority or the white balance priority is determined when the display of the LCD display unit 10 is turned on.
As shown in FIG. 10, the setting can be changed by displaying a setting menu on the LCD display unit 10 and performing a menu operation. The setting menu in FIG. 10 shows that the UP switch 6 or the DOWN key 7
Is pressed, and the processing of the setting change routine is performed.

FIG. 11 is a flowchart showing a setting change routine. When the setting change routine is called, the current setting state is displayed in step S901. Items shaded and displayed with black circles in FIG. 10 are current selection items.

Then, it is determined in step S902 whether or not the shutter button 9 (in this case, used for updating the selected state) has been pressed, and if it is determined that the shutter button 9 has not been pressed (No), the process proceeds to step S902. The process proceeds to S903, and if it is determined that the button is pressed (Yes), the process proceeds to step S903.
Move to 910.

In step S903, it is determined whether the UP switch 6 or the DOWN switch 7 (in this case, used for selecting a selection item) has been pressed, and if it is determined that the switch has been pressed (Yes), the process proceeds to step S904. If it is determined that the button has not been pressed (No), the process returns to step S901.

When the UP switch 6 or the DOWN switch 7 is pressed, in step S904, the cursor 920 (underlined portion) of the item setting moves.
When this menu is opened, the cursor is on the top line L1, and when the DOWN switch 7 is pressed, the cursor moves to the lower item,
Pressing the UP switch 6 moves to the upper item. FIG. 10 shows a state in which the menu is opened and the DOWN key is pressed four times, and therefore, is on the line L5 that has passed from the first line L1 to L2, L3 and L4.

Then, in step S905, the item indicated by the cursor is set to the selected state. For example, in the state shown in FIG. 10, the item "employed at the previous detection (mode 1)" in the row L5 where the cursor is placed is in the selected state.

If it is determined in step S 906 that the LCD display unit 10 is in the display ON state and the flash is in the light emission OFF state (LF_State = 2) (Yes), the flow shifts to step S 907, and it is determined otherwise (step S 907). No) and returns to step S901.

Therefore, after the item displayed by the cursor has been selected, the process returns to step S901. If it is determined in step S902 that the shutter button 9 has been pressed, the process proceeds to step S910. Then, in step S910, by newly setting the item of the selected state, the setting state is updated, and the setting change routine ends.

On the other hand, in step S907, the live view mode is determined. If the live view mode is mode 1, after setting the shutter priority in step S908,
Returning to step S901, if the live view mode is mode 2, white balance priority is set in step S909, and the process returns to step S901.

<Flow of LCD Display ON Process> FIG.
5 is a flowchart showing the flow of processing of an LCD display ON processing routine when the LCD display is changed from the OFF state to the ON state after the power is turned on.

When the LCD display is turned on after the power is turned on, there is a concept that the priority relationship between the live view mode and the white balance / shutter is controlled according to Table 1. However, in order to prevent battery consumption, the liquid crystal display is controlled. In many cases, the display slide switch 16 is frequently turned on and off. In each case, the L is set after power is turned on in consideration of the inconvenience and inconvenience of updating the settings each time.
The setting is retained and not updated only by turning on / off the CD display unit.

Therefore, if the current setting is determined to be white balance priority in step S1001 (Yes), the process ends with white balance priority maintained in step S1002.

On the other hand, if it is determined in step S1001 that the shutter priority is given (No), the process proceeds to step S1004 after the shutter priority is held in step S1003.

Further, in step S1004, the live view mode is determined. When it is determined that the live view mode is 1 ("1"), the process is terminated in step S1005 while the live view mode 1 is held, and the live view mode 2 is terminated. Is determined (“2”), step S1006
To hold the live view mode 2 and end the processing. After the power is turned on, the LCD display unit 10 is turned off from the ON state.
Even when the F state is set, the setting when the LCD display is turned ON is maintained.

<Flow of Imaging Process> FIGS. 13 and 14 are flowcharts showing the flow of the imaging process when the shutter button is pressed in the above-described setting state. This process is performed under the control of the overall control unit 211.

First, in step S1101, the S1 state (half-pressed state) of the shutter button 9 is detected. If the S1 state is detected (Yes), the process proceeds to step S1102 and the subsequent steps, and if the S1 state is not detected (No). ) Terminates the processing.

In step S1102, it is determined whether the creation of the white balance level conversion table has been completed. If completed (Yes), the processing in step S1116 and subsequent steps are performed. If not completed (No), processing in step S1103 and subsequent steps will be performed. Is performed.

As shown in FIG. 14, step S1103
To start creating a level conversion table, and step S11
At 04, a display during white balance setting is performed (see FIG. 15). On the screen of the LCD display unit 10 shown in FIG.
The live view image is displayed in the area A1 in the state, and a character string “white balance is being set” is displayed in the display line L11. Note that the live view image is not updated during the white balance setting.

In step S1105, it is determined whether or not the shutter button 9 is in the S1 state. If it is in the S1 state (Yes), the process returns to step S1102, and
If not (No), the process moves to step S1106.

In step S1106, it is determined whether or not the shutter button 9 is in the S2 state (fully pressed state). If the state is not the S2 state (No), step S1102
Return to step S1 if the state is S2 (Yes).
Move to 108.

In step S1108, it is determined whether or not the creation of the white balance level conversion table has been completed. If completed (Yes), the processing in step S1109 and subsequent steps are performed. If not completed (No), step S1112 and subsequent steps are performed. Is performed.

In step S1109, the level conversion table is held as a parameter at a predetermined address of a work memory (not shown) of the overall control unit 211, and the process proceeds to step S1109.
At 110, the white balance setting display is turned off.

Thereafter, step S1111 shown in FIG.
Then, in step S1111, white balance correction is performed using the parameters of the level conversion table described above, and in step S1119, a series of processes for capturing the captured image and recording the captured image in the memory card 8 are performed, and the routine ends.

On the other hand, if the creation of the level conversion table has not been completed in step S1108, the process proceeds to step S1108.
At 112, it is determined whether the setting state is shutter priority.
In step S1112, it is determined that shutter priority is given (Y
es), and the process proceeds to step S1113 and the subsequent steps for performing the imaging process using the existing level conversion table. If it is determined that the white balance is prioritized (No), the process returns to step S1102 without performing the imaging process.

In step S1113, it is determined whether or not the level conversion table has already been stored in the work memory. If the level conversion table has not been stored (No), the process jumps to step S1115. If it has been stored (Yes), the process proceeds to step S1114. Transition.

In step S1114, it is determined which of the following modes is to be used for adopting an existing level conversion table with shutter priority. Shutter priority first mode: employs a level conversion table created most recently. Shutter priority second mode: A preset level conversion table is called in accordance with the determination results by the image determination unit 211e and the scene determination unit 211c.

In step S1114, the first shutter priority is set.
If it is determined that the mode is the mode ("1"), the process immediately jumps to step S1111. If it is determined that the mode is the shutter priority second mode in step S1114 ("2"), the process proceeds to step S1115.

Step S1115 is performed by the scene determination section 21
1c and the determination result of the image determination unit 211e (memory 211
(stored in d) is newly stored in the work memory, and the process jumps to step S1111.

Then, step S1111 shown in FIG.
Then, white balance correction is performed using the parameters of the existing level conversion table determined by the above-described processing in the case of the shutter priority, and a series of processing for capturing the image captured in step S1119 and recording it on the memory card 8 is performed. To end.

Therefore, in the case of the shutter priority, even if the shutter button 9 is set to the S2 state during the process of creating the level conversion table, it is possible to quickly execute the imaging process of obtaining an image signal based on the optical image of the subject. Because you can, you never miss a photo opportunity.

<Flow of Image Capture Recording Processing Routine> FIGS. 16 and 17 are flowcharts showing an image capture recording processing routine corresponding to step S1119 of FIG.

Referring to the figure, first, at step S120
In step 1, it is determined whether the display during white balance setting is in the ON state. If the display is not in the ON state (No), it is considered that the creation of the level conversion table for white balance setting is completed, and the process jumps to step S1202. In the case of the ON state (Yes), since the image is taken with the shutter priority, it is considered that there is a possibility that the white balance is out of order, and the processing shifts to the processing after step S1204.

At step S1202, the image memory 209-
1 temporarily stores the captured image. Next, in step S1203 shown in FIG. 17, the image data of the image memory 209-1 is recorded on the memory card 8, and this routine ends.

Steps S1204 to S12 shown in FIG.
The process of 16 is a process of recording, on the memory card 8, only the image data for which the white balance is determined to be most appropriate among the six image data stored in the image memories 209-1 to 209-6.

In step S1204, first, the display during white balance setting is turned off. Then, in step S1205, the count coefficient k is initialized to “1”.

Then, in step S1206, image data based on the optical image of the subject is captured from the k-th CCD 303, and the captured image data is temporarily stored in the image memory 209-k.

Then, k is “6” in step S1207.
It is determined whether or not has been reached. If the value has reached “6” (Yes), the process proceeds to step S1209, and if not (No), the process proceeds to step S1208.

In step S1208, the counter coefficient k is set to 1
Increment and return to step S1206. Or later,
The processes of steps S1206 to S1208 are repeated until k = 6 is determined in step S1207. Therefore, after the processes of steps S1206 to S1208 are performed a total of six times, the process proceeds to step S1209.

Therefore, even if the shutter button 9 is set to the S2 state during the white balance setting, the six white balance corrected image data are stored in the image memory 209-1.
209-6, the best image data can be selected from the six pieces of image data by the selection processing in steps S1210 to S1216 described below.

In step S1209, the count coefficient k is again initialized to "1", and step S1 shown in FIG.
In step 1210, in the image data in the image memory 209-k, the average values Rm, Gm, and Bm of the R, G, and B components of the image data in the central part and the peripheral specific area of the imaging range are obtained, and the average value comparison coordinates ( Gm / Rm, Gm / Bm) are within the determination rectangular area 122 in FIG.

In step S1210, rectangular area 1 for determination
If it is determined that the white balance is within the range of 22 (Yes), it is considered that the white balance is almost appropriate, and the process proceeds to step S
After calculating the white balance evaluation value E (k) = | Gm / Bm-Gm / Rm | of the image memory 209-k in step 1211, the process proceeds to step S1212. Evaluation value E (K)
Is smaller, the straight line 121 in FIG. 18 (G / B = G / R)
, Indicating that the white balance is being properly performed.

On the other hand, if it is determined in step S1210 that it is outside the range of the determination rectangular area 112 (No), step S1211 is skipped because the calculation in step S1211 is meaningless, and the process proceeds to step S1212.

Then, in step S1212, k is "6".
It is determined whether or not has been reached. If it has reached “6” (Yes), the process moves to step S1214, and if it has not reached (No), the process moves to step S1213.

In step S1213, the counter coefficient k is set to 1
Increment and return to step S1210. Or later,
The processing of steps S1210 to S1213 is repeated until k = 6 is determined in step S1212. Therefore, after the processes of steps S1210 to S1213 are performed a total of six times, the process proceeds to step S1214.

In step S1214, it is determined whether or not the average comparison coordinates of all the image data in the image memories 209-1 to 209-6 are out of the range of the determination rectangular area 122.

In step S1214, when all the average comparison coordinates are out of the range of the determination rectangular area 122 (Ye
In step s), the image data stored in the image memories 209-1 to 209-6 is regarded as having an inappropriate white balance, and a warning display (see FIG. 19) is performed on the LCD display unit 10 in step S 1217.

Therefore, image memories 209-1 to 209-1
When all the image data stored in 9-6 is evaluated to be out of the range of the determination rectangular area 122, a warning is displayed on the LCD display unit 10 to notify the photographer of the failure of the imaging process. It is possible to notify the user surely, to prompt the photographer to perform the photographing process again, and to avoid missing a photo opportunity.

Thereafter, the image data of the image memory 209-1 is recorded on the memory card 8 in step S1218.
Therefore, even when all the image data stored in the image memories 209-1 to 209-6 are evaluated to be out of the range of the determination rectangular area 122, the image memory 209-1 is also determined.
Can be recorded on the memory card 8 without fail.

If at least one of the average value comparison coordinates is within the range of the determination rectangular area 122 in step S1214 (No), it is determined that image data having an appropriate white balance exists, and in step S1215, the image data is obtained in step S1211. Among all the evaluation values E (k), the count coefficient k of the evaluation value E (k) that takes the minimum value is determined as the optimum count coefficient km, and the image data of the image memory 209-km is stored in the memory card 8 in step S1216. Record.

As a result, of the six frames of image data shot in the S2 state of the shutter button 9 and stored in the image memories 209-1 to 209-6, the image data having the most appropriate white balance is automatically determined. It can be selected and recorded on the memory card 8. Considering that even when the same subject is photographed, the white balance differs depending on the timing of photographing due to various external factors, even if photographing is performed with shutter priority, the image data recorded on the memory card 8 by the above automatic selection is considerably large. The image quality is high.

[0127]

As described above, the overall control means of the digital camera according to the first aspect of the present invention updates the correction condition set value at the time of preparation for image pickup, and performs image pickup during the update of the correction condition set value. In the execution state, the corrected image signal obtained by performing the image correction using the existing correction condition value as the correction condition setting value is continuously output from the captured image image correction unit a plurality of times, and the output plurality of corrected images are output. Each signal is stored in the image storage means.

Therefore, even if the image capturing is executed during the updating of the correction condition setting value, the image capturing process of storing the corrected image signal based on the optical image of the subject in the image storage means can be executed quickly. Never miss a photo opportunity.

In addition, since a plurality of corrected image signals are stored in the image storage means, a corrected image signal having good image quality can be selected from the plurality of corrected image signals.

Further, the overall control means of the digital camera according to the present invention evaluates the plurality of corrected image signals stored in the image storage means by a predetermined evaluation method, and evaluates the plurality of corrected image signals. It has an evaluation function of determining the corrected image signal having the best evaluation, and when the imaging execution state is reached during the update processing of the correction condition set value, the corrected image signal having the best evaluation is recorded on a recording medium. Have recorded.

As a result, the corrected image signal having the best evaluation by the evaluation function is recorded on the recording medium. Therefore, even if the corrected image signal is obtained using the existing correction condition value as the correction condition setting value, A corrected image signal having good image quality can be recorded on a recording medium.

The digital camera overall control means according to the third aspect of the present invention has an evaluation function for determining whether or not the corrected image signal satisfies a predetermined standard. When the imaging execution state is entered during the update processing of the correction condition setting value, the image correction unit outputs a corrected image signal that has been subjected to image correction using the existing correction condition value as the correction condition setting value, When it is determined that the corrected image signal does not satisfy the predetermined criterion, the notification unit is notified of a warning state.

Therefore, even if the imaging execution state is entered during the updating of the correction condition setting value, the imaging processing of obtaining a corrected image signal based on the optical image of the subject can be executed quickly, and a photo opportunity is missed. Never.

In addition, when it is evaluated that the corrected image signal does not satisfy the predetermined criterion, the notifying means is notified of the warning state, so that the photographer can be sure of the failure of the image pickup processing. , And prompting the user to perform the photographing process again.

Further, the digital camera overall control means records the corrected image signal on the recording medium irrespective of the evaluation result by the evaluation function when the imaging execution state is entered during the correction condition setting value update processing. Therefore, the corrected image signal based on the optical image of the subject can be always recorded on the recording medium even during the imaging execution state during the update processing of the correction condition setting value.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a digital camera according to an embodiment of the present invention.

FIG. 2 is a rear view illustrating a configuration of the digital camera according to the embodiment;

FIG. 3 is a bottom view illustrating a configuration of the digital camera according to the embodiment;

FIG. 4 is a block diagram illustrating a configuration of the digital camera from a functional viewpoint.

FIG. 5 is an explanatory diagram showing a relationship between a state of a shutter button and a white balance calculation time.

FIG. 6 is an explanatory diagram showing a state of a shutter button.

FIG. 7 is a block diagram showing details of an internal configuration of an overall control unit in FIG. 4;

FIG. 8 is an explanatory diagram schematically showing the storage contents of a memory card.

FIG. 9 shows a power supply O in the digital camera according to the embodiment.
9 is a flowchart illustrating a flow of a setting state determination process immediately after N.

FIG. 10 is an explanatory diagram showing a setting menu displayed on the LCD display unit.

FIG. 11 is a flowchart illustrating a flow of a setting change process after the power is turned on in the digital camera of the embodiment.

FIG. 12 is a flowchart illustrating a flow of a setting state determination process when the LCD display is turned on after the power is turned on in the digital camera of the embodiment.

FIG. 13 is a flowchart illustrating a flow of a shutter button process at the time of imaging in the digital camera of the embodiment.

FIG. 14 is a flowchart illustrating a flow of a shutter button process at the time of imaging in the digital camera of the embodiment.

FIG. 15 is an explanatory diagram showing an LCD display unit for displaying that white balance is being set.

FIG. 16 is a flowchart showing a flow of an image capturing and recording process in the digital camera of the embodiment.

FIG. 17 is a flowchart illustrating a flow of an image capturing and recording process in the digital camera of the embodiment.

FIG. 18 is a graph for explaining a determination process using a determination rectangular area.

FIG. 19 is an explanatory diagram showing an LCD display unit for displaying that white balance is inappropriate.

[Explanation of symbols]

5 Built-in flash, 8 memory card, 9 shutter button, 11 FL mode setting switch, 16 liquid crystal display slide switch, 21 optical viewfinder, 20
7 WB (white balance) circuit, 209-1 to 20
9-6 image memory, 214 flash control circuit, 2
50 Operation unit.

Claims (4)

[Claims] An imaging unit configured to convert an optical image of a subject into an image signal; and an image configured to correct the image signal based on a correction condition set value set according to the image signal and output a corrected image signal. A correction unit; an image storage unit that stores the corrected image signal; and an overall control unit that controls operations of the imaging unit, the image correction unit, and the image storage unit. At this time, the correction condition setting value is updated, and when the imaging execution state is entered during the correction condition setting value updating process, the captured image image correcting unit performs image correction using the existing correction condition value as the correction condition setting value. A digital camera that continuously outputs the corrected image signal that has been subjected to the above two or more times, and stores the plurality of output corrected image signals in the image storage unit. 2. The image processing apparatus according to claim 1, further comprising: a recording medium on which a corrected image signal can be recorded under the control of the general control unit, wherein the general control unit stores the plurality of corrected image signals stored in the image storage unit. An evaluation function of evaluating a predetermined evaluation method to determine a corrected image signal having the best evaluation among the plurality of corrected image signals; and 2. The digital camera according to claim 1, wherein when the imaging state is reached during the update processing, the corrected image signal having the best evaluation is recorded on the recording medium. 3. An image pickup means for converting an optical image of a subject into an image signal, and an image for correcting the image signal based on a correction condition set value set according to the image signal and outputting a corrected image signal. A correcting unit, a notifying unit capable of notifying that a warning state has occurred, and an overall control unit that controls operations of the imaging unit, the image correcting unit, and the notifying unit. An evaluation function for determining whether or not the corrected image signal satisfies a predetermined criterion; the overall control unit performs an update process of the correction condition set value at the time of preparing for imaging; When the imaging execution state is entered during the update process, the image correction unit outputs the corrected image signal obtained by performing the image correction using the existing correction condition value as the correction condition setting value, and outputs the corrected image signal. No. is when evaluated does not satisfy the predetermined reference, thereby notifying that the warning state to said notification means,
Digital camera. 4. A recording medium on which the corrected image signal can be recorded, wherein the general control unit, when in an imaging execution state during an update process of the correction condition set value, relates to an evaluation result by the evaluation function. The digital camera according to claim 3, wherein the corrected image signal is recorded on the recording medium without any modification.