JP2001128106A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the memory efficiency of an image pickup device which takes in an entire image and partial images of a subject in order to generate a high-definition picture by composing pictures of plural parts, into which the entire subject is divided, based on the picture of the entire subject. SOLUTION: A digital camera 1 successively picks up images of the entire subject and plural divided parts of the subject while changing the direction of the optical axis of an image pickup 2. Pixel data constituting the picture of the entire subject is subjected to prescribed processing by a picture processing part 24 and is stored in a memory card 10 as it is. Pixel data constituting pictures of parts of the subject is stored in the memory card 10 after subjected to level conversion in a gradation conversion part 24 by using the level of pixel data, which has the same relation as pertinent pixel data with respect to light reception position and constitutes the picture of the entire subject, so that the number of gradations may be reduced. The number of gradations of pixel data constituting pictures of parts of the subject is reduced to reduce the data capacity, and the memory efficiency of the memory card 10 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for capturing an image of an entire object, and enlarging and imaging each part obtained by dividing the object into a plurality of parts to substantially the same size as the entire object. An imaging apparatus that enables creation of a high-definition captured image by synthesizing the captured image of each part of the subject based on the captured image of
More specifically, the present invention relates to an imaging apparatus capable of reducing the number of data of a captured image of each part of a subject and increasing the efficiency of an image memory.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for storing image data.

For example, Japanese Patent Application Laid-Open No. 10-79874 discloses a method for recording an image captured by a digital camera on an IC card by temporarily storing an image captured by an image sensor in an image memory and using the stored image as a JPEG image. (Jo
1 shows a method of recording, on an IC card, a captured image compressed by an int Photographic Coding Experts Group) method and a thumbnail image created by thinning processing.
In this recording method, since a thumbnail image is recorded together with the compressed image, the use of the thumbnail image makes it possible to easily create an index image for checking and retrieving an already photographed image. .

Further, an LCD (Liquid Crystal Display)
In a digital camera equipped with a display unit, a small-sized display image is created by thinning-out processing using a captured image stored in an image memory, and the display image is output to an LCD display unit, so that a finder display or the like can be achieved. Monitor display of the captured image is performed.

A new image format has been jointly developed and proposed as a method of recording image data on a recording medium by four companies such as Eastman Kodak Company in the United States. In this image format, digital images captured by a scanner or digital still camera are used as basic image data.
A plurality of image data are created with the resolution of the basic image data being the maximum value and the resolution is reduced by 1/4 to a minimum resolution of 64 × 64 pixels, and these image data are saved as one group of image data in one file. ("New image file format FlashPi
x "Journal of the Institute of Image Electronics Engineers of Japan Vol. 27 No. 2 (1998) P9
8-P106).

[0006]

By the way, in order to obtain an image of the entire subject by dividing the subject into a plurality of parts and taking an image, and combining the partial images to obtain an image of the entire subject, the entire subject is imaged and the subject is photographed. When each part is imaged and the data of these captured images is recorded as one file on a recording medium, a plurality of sheets (the number of divisions N +
Image data for one image).
The storage efficiency of the recording medium decreases. Therefore, it is desirable to reduce the number of data to be recorded on the recording medium as much as possible to improve the storage efficiency.

As a method for reducing the number of data, compression processing such as the conventional JPEG method or thinning processing can be applied. However, since one image file is composed of a plurality of shot images and the data capacity is large, There is a problem that time is required for compression processing and the like. Therefore, it is desirable to reduce image data by a relatively simple method, and then to reduce the number of data by compression processing or thinning processing as necessary.

On the other hand, the new image format creates image data of a plurality of resolutions from an original digital image, so that the convenience in performing various image processing from a recorded image is improved, but the creation of a high-definition image is improved. If only the recording efficiency of a captured image in a possible digital camera is considered, the number of data in one image file increases, and the storage efficiency further decreases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an image of an entire subject and each part obtained by dividing the subject into a plurality of parts. In an imaging device capable of obtaining a high-definition captured image by synthesizing images so as to be pasted together, an imaging device capable of reducing the data capacity of one image file as much as possible and improving storage efficiency is provided. is there.

[0010]

According to the present invention, there is provided an image pickup surface in which a plurality of pixels are two-dimensionally arranged, and a light image formed on the image pickup surface is photoelectrically converted by each pixel into an electric signal. Imaging means for imaging, an image magnification changeable imaging means for imaging a subject light image on the imaging surface of the imaging means, and forming an optical image of the entire subject on the imaging surface by the imaging means. The entire subject is imaged, and the light image of each part obtained by dividing the entire subject into a plurality is enlarged to substantially the same size as the imaging size of the entire subject by the imaging means to form an image on the imaging surface. Image capturing control means for sequentially capturing each part of the subject, and storage means for storing pixel data constituting an image captured by the image capturing means, wherein the image of the subject is determined based on a captured image of the entire subject. Combine so that the captured images of each part are pasted together In the image pickup apparatus to enable the creation of high-resolution captured image Rukoto, to reduce the number of gray levels of the pixel data constituting the captured image of each part of the subject,
Level conversion for level-converting the level of each pixel data forming the captured image of each part of the subject using the level of the pixel data forming the captured image of the entire subject having the same relationship as the pixel data and the light receiving position. Means, and storage control means for storing, in the storage means, pixel data constituting a captured image of the entire subject and pixel data constituting a captured image of each part of the subject which has been level-converted by the level conversion means. It is provided (claim 1).

The level converting means forms a captured image of the entire subject having the same relationship between the pixel data and the light receiving position from the level value of each pixel data constituting the captured image of each portion of the subject. The level may be converted to a level value of a difference obtained by subtracting the level value of the pixel data (claim 2).

According to the above arrangement, a high-resolution captured image can be obtained by combining the captured images of the respective parts obtained by dividing the entire subject into a plurality of parts based on the captured image of the entire subject. The optical image of the entire subject is formed on the imaging surface of the imaging unit by the imaging unit to capture the entire image of the subject, and the pixel data forming the captured image of the entire subject is stored in the storage unit.

Further, the light image of each part obtained by dividing the entire subject into a plurality of parts is enlarged by the image forming means to a size substantially equal to the image pickup size of the entire subject and formed on the image pickup surface of the image pickup means. Each partial image is sequentially captured. The level value of the pixel data constituting the captured image of each part of the subject is different from the level value of the pixel data constituting each captured part of the subject so as to reduce the number of gradations of the pixel data constituting the captured image of each part of the subject. The level value of the pixel data is level-converted using the level value of the pixel data constituting the captured image of the entire subject having the same relationship as the pixel data and the light receiving position, and the pixel data after the level conversion is stored in the storage unit. Is done.

The level value of the pixel data forming the captured image of each part of the subject is, for example, the same relationship between the pixel data and the light receiving position based on the level value of each pixel data forming the captured image of each part of the subject. The level is converted into a level value of a difference obtained by subtracting the level value of the pixel data constituting the captured image of the entire subject, and is stored in the storage unit.

As a result, the number of gradations of the pixel data constituting the captured image of each portion of the subject is reduced, and the total number of data of the captured image of each portion of the subject is reduced.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An imaging apparatus according to the present invention will be described.
A digital camera will be described as an example.

FIG. 1 is a perspective view showing an appearance of a digital camera according to an embodiment, and FIG. 2 is a rear view of the digital camera. FIG. 3 is a diagram showing a schematic configuration of an imaging system of the digital camera.

The digital camera 1 has an image pickup section 2 provided at a substantially central portion of the front surface thereof so as to be able to change an optical axis direction L, and a photometry section 3 for measuring the luminance of a subject is provided above the image pickup section 2. A distance measuring unit 4 for measuring a subject distance laterally,
A flash 5 is provided on the right side of the photometry unit 3.

As shown in FIG.
Lens 2 consisting of a zoom lens protruding from the front of the camera
02 and an image sensor 203 including a CCD area sensor disposed at a predetermined position on the optical axis L in the housing 201. A pair of rotation shafts 201a is provided on the side surface of the housing 201 in a direction perpendicular to the optical axis L, and both the rotation shafts 201a
Are rotatably supported at both ends of a U-shaped support frame 201b. A rotation shaft 201c projects outward from the center of the U-shaped support frame 201b, and the tip of the rotation shaft 201c is connected to the rotor of the electric motor 18. Also,
The tip of one rotating shaft 201 a is connected to the rotor of the electric motor 19.

The electric motor 18 is a drive source for rotating the housing 201 in the left and right direction (H direction in the figure), and the electric motor 19 is for rotating the housing 201 in the up and down direction (V direction in the figure). It is a driving source. When the electric motor 18 is driven, the U-shaped support frame 201b connected to the rotor rotates in a horizontal plane, whereby the housing 201 rotates so that the optical axis L changes in the horizontal plane. In addition, when the electric motor 19 is driven, the rotating shaft 201a connected to the rotor rotates, whereby the housing 201 rotates so that the optical axis L changes in a vertical plane.

An electric motor 20 for changing the zoom ratio and an electric motor 21 for adjusting the focus are provided on the lens barrel of the taking lens 202, and a predetermined zooming lens in the taking lens 202 is driven by the electric motor 20. To change the zoom ratio, and the electric motor 21
The focus adjustment is performed by driving a predetermined focusing lens in 02.

The photometric unit 3 is an SPC (silicon photo cell)
And the like, and receives the reflected light from the subject to detect the brightness of the subject. The distance measuring unit 4 detects a distance to a subject by, for example, an active distance measuring method. The distance measuring unit 4 has a light emitting element for irradiating the subject with infrared light and a light receiving element for receiving the reflected light of the infrared light from the subject, and a camera based on the reflection angle of the infrared light on the subject. From the object to the subject.

On the upper surface of the digital camera 1, a shutter button 6 is provided at the left end. The shutter button 6 is an operation button that turns on an S1 switch for instructing photographing preparation such as focus adjustment and exposure control value setting when pressed halfway, and turns on an S2 switch for instructing release when fully pressed. In addition, a power switch 7 and a card insertion slot 8 into which the memory card 10 is inserted / removed are provided at the lower side of the digital camera 1, and a card for ejecting the memory card 10 inserted above the card insertion slot 8 is provided. An extraction button 9 is provided. When printing the shooting results on recording paper,
When the memory card 10 is removed from the digital camera 1 by pressing the card ejection button 9 and the memory card 10 is attached to, for example, a printer in which the memory card can be attached, the data of the captured image is directly read out from the memory card 10 and printed on the recording paper Can be printed.

A connection terminal 11 for externally connecting a personal computer (hereinafter, referred to as a personal computer) is provided on the upper side of the digital camera 1. The connection terminal 11 is, for example, a SCSI (Small Computer System).
m Interface or USB (Universal Serial)
It is configured with a connection interface conforming to the Bass) standard, and a dedicated cable (SCSI cable or USB cable) for connecting to a personal computer can be connected.

In the present embodiment, a memory card is used as a recording medium for image data, but the recording medium is not limited to this, and a hard disk card,
Other recording media such as a floppy disk and a mini disk may be used.

As shown in FIG. 2, on the rear surface of the digital camera 1, a display unit 12 (hereinafter, referred to as an LCD display unit 12) comprising an LCD (Liquid Crystal Display) is provided substantially at the center.
Is provided. The LCD display unit 12 corresponds to an optical finder. When the digital camera 1 is started, video shooting is performed by the imaging unit 2, and the photographed image (preview image) is displayed on the LCD display unit 12, so that the photographer can take a picture. The subject in the shooting screen can be monitored. When the photographer presses the shutter button 6 to perform a photographing operation, the photographed image of the still image is recorded on the memory card 10, while the photographed image immediately after the release is displayed as a still image on the LCD display unit 12. Can monitor the photographed image (still image) on the LCD display unit 12.

Further, the digital camera 1 has a high resolution in a photographing mode in which a subject is divided into a plurality of parts, and a partially photographed image (hereinafter, referred to as a partial image) is synthesized by image processing and combined. There is a photographing mode (hereinafter, this photographing mode is called a high-resolution mode) that can generate an image of the entire subject (hereinafter, called a high-resolution photographed image). Even in this high-resolution mode, the entire subject is photographed first. The captured image (still image) is displayed on the LCD display unit 12.
, The photographer can quickly monitor the contents of the synthesized image (high-definition photographed image).

On the right side of the LCD display section 12, a mode setting switch 13 which is also used as a power switch is provided. The mode setting switch 13 switches on / off the power, a recording mode, a reproducing mode, and a PC mode. The recording mode is a mode in which a photograph is taken, and the playback mode is a mode in which a photographed image recorded in the memory card 10 is
The PC mode is a mode for reproducing on the CD display unit 12. The PC mode communicates with an externally connected personal computer to perform predetermined processing (eg, transfer of recorded images, remote shooting from the personal computer, and the like).
Is what you do. The mode setting switch 13 is a four-contact slide switch. The power is turned off at the "OFF" position, and the power is turned on at other positions (that is, the setting positions of the respective modes). "REC", "PL
The positions “AY” and “PC” are the setting positions of the recording mode, the reproduction mode, and the PC mode.

On the left side of the LCD display section 12, a still image display release button 14 is provided. The still image display release button 14 is used to reset the display mode of the LCD display unit 12 which is automatically switched from moving image display to still image display every time shooting processing is performed, from still image display to moving image display for the next shooting. Operation buttons. The reason why the operation of returning the display mode is performed by the manual operation of the operator is to improve the convenience of monitoring the captured image without fixing the monitoring time. After the still image display is performed for a predetermined period of time, the still image display release button 14 may be omitted by automatically returning from the still image display to the moving image display.

A high-resolution mode setting switch 15 is provided at the lower left corner of the back of the digital camera 1 and a composite image number setting switch 16 is provided at the right corner. An image selection switch 17 is provided between the high-resolution mode setting switch 15 and the number-of-combined-images setting switch 16 for selecting a reproduction image in the reproduction mode and a transfer image in the PC mode. The image selection switch 17 includes an up switch 17a and a down switch 17b.
And a confirmation switch 17c. The up switch 17a is a switch for selecting a captured image in an ascending order, and the down switch 17b is a switch for selecting a captured image in a descending direction. Further, the confirmation switch 17c is an up switch 17a or a down switch 1
A switch for confirming the image selected in 7b as a reproduced image or a transfer image.

The high resolution mode setting switch 15 is a switch for setting the above high resolution mode. When the high-resolution mode setting switch 15 is set to “ON”, the high-resolution mode is set. When the high-resolution mode setting switch 15 is set to “OFF”, the normal shooting mode is set.

In the high resolution mode, when the shutter button 6 is fully pressed, first, the optical axis L of the imaging section 2 is set to the front direction, and the entire subject is photographed. That is, since the optical axis L of the imaging unit 2 is initially set in the front direction (o direction) as shown in FIG. 4, the screen configuration is such that the entirety of the subject Q (scenery in the figure) falls within the shooting screen P1. Is adjusted and the shutter button 6 is pressed, the entire subject Q is photographed.

The photographed image (hereinafter, the whole photographed image is referred to as a whole image) is stored in a predetermined storage area of the memory card 10 and the LCD display 12
Is displayed on the screen. Therefore, in the high resolution mode, an image having the same content as the entire image finally synthesized immediately after the release is displayed on the LCD display unit 12, and the content of the entire image after the synthesis can be quickly monitored.

Subsequently, assuming that the number of divisions N is 4, for example, the optical axis L of the imaging section 2 is changed in a predetermined direction other than the front direction, and the photographing magnification is changed to a predetermined magnification β corresponding to the number of divisions N.
(= N / 2), and partial images obtained by dividing the entire object into four (capture of partial images) are sequentially performed.

That is, as shown in FIG. 4, the direction of the optical axis L of the image pickup unit 2 is changed to a predetermined direction (a direction) in which the upper left part of the object Q is viewed toward the object Q. / 4 so that / 4 falls within the shooting screen P2.
The photographing magnification of 02 is increased to about twice, and photographing of the upper left portion of the subject Q is performed. At this time, the angle of view at the time of capturing the partial image of the subject Q is set such that the boundary portions of the adjacent partial images overlap each other. After this, shooting lens 2
02, without changing the magnification, the direction of the optical axis L of the imaging unit 2 is sequentially changed in a predetermined direction (c, d, b directions) in which the upper right, lower right, and lower left portions of the subject Q are viewed. Then, the upper right portion, the lower right portion, and the lower left portion of the subject Q are photographed. Then, the level of each pixel data of each partial image is level-converted using the corresponding pixel data of the entire image so as to reduce the number of gradations.
Is stored in a predetermined storage area. The level conversion method of the pixel data of the partial image will be described later.

In FIG. 4, since the photographing screens P1 and P2 are relatively drawn around the subject Q, the photographing screen P2 is smaller than the photographing screen P1. Since the sizes of the shooting screen P1 and the shooting screen P2 are the same, the subject Q is projected on the imaging surface in a smaller size than the shooting screen P2 in the screen configuration of the shooting screen P1. Therefore, since the whole image has a lower resolution than the partial image due to the relationship between the projection light image and the pixel density, the resolution of the entire subject image obtained by synthesizing the partial images is higher than that of the whole image.

In the digital camera 1 according to the present embodiment, only the entire image and a plurality of partial images are stored in the memory card 10, the data of these captured images are transferred to a personal computer, and a high-resolution captured image is created on the personal computer side. Have to be able to.

As shown in FIG. 5, the high-resolution photographed image is subjected to interpolation processing of the entire image G to generate an image G 'enlarged to four times the size, and to convert each of the partial images G _{A to} G _D into this enlarged image. G ′, and calculates a combined position with respect to the enlarged image G ′ and a conversion amount of image data for correcting image distortion, respectively.
After converting the respective partial images G _A ~G _D geometrically on the basis of the conversion amount, synthesizing the partial images G _A ~G _D after the image conversion based on the composite position as bonded at the boundary Created. In the example of FIG. 5, the imaging magnification of the partial images G _A ~G _D is about twice the whole image after the synthesis (high-definition photographic image) is an image G, i.e., taken with normal shooting mode object It has approximately four times the resolution of the entire image.

The digital camera 1 may be provided with an image synthesizing unit for creating a high-definition photographed image, and the high-definition photographed image may be stored in the memory card 10.

On the other hand, in the normal photographing mode, when the shutter button 6 is pressed, the photographing operation is performed only once, and the photographed image is subjected to a predetermined image processing (appropriate γ correction,
After performing WB adjustment, contour correction, color unevenness correction, and the like, the image is recorded on the memory card 10. This photographing processing is substantially equivalent to performing predetermined image processing on the entire image G in the high-resolution mode and recording it on the memory card 10.

Returning to FIG. 2, the composite image number setting switch 16
Is a switch for setting the number of partial images in the high resolution mode (that is, the number of divisions N of the subject). The composite image number setting switch 16 can set the vertical division number n and the horizontal division number m when dividing the subject into an n × m matrix in a maximum of four. The number-of-synthesized-images setting switch 16 includes a pair of four-contact slide switches 16a and 16b. The number of divisions n in the vertical direction is set by the upper slide switch 16a, and the number m of divisions in the horizontal direction is set by the lower slide switch 16b. Is done.

In this embodiment, the photographer is divided into N
Can be set, but a predetermined number of divisions N may be fixedly set in advance, and the composite image number setting switch 16 may be omitted.

FIG. 6 is a block diagram showing a digital camera according to an embodiment of the present invention.

In the figure, thick arrows indicate the flow of image data, and thin arrows indicate the flow of control data. The same members as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

The control unit 33 controls the photographing operation of the digital camera 1 centrally, and comprises a microcomputer. The control unit 33 controls driving of various members described later.

The imaging control unit 22 controls the driving of the imaging unit 2. The imaging control unit 22 includes a zoom control unit 221,
Focus control unit 222, scan control unit 223, and CCD
The control unit 224 is provided. The zoom control unit 221 controls the zoom ratio (photographing magnification β) of the imaging lens 202. The photographing magnification β is changed when capturing a partial image in the high-resolution mode, and is set in advance according to the number of partial images (that is, the number of divisions N of the subject).
Information on the number of divisions N of the subject set by the composite image number setting switch 16 is input to the imaging control unit 22 via the control unit 33, and the zoom control unit 221 responds based on the input information on the number of divisions N of the subject. Then, the electric motor 19 is driven based on the photographing magnification β to set the imaging lens 202 to a predetermined photographing magnification β.

The focus control unit 222 includes the imaging lens 20
The second focus is automatically adjusted. The control unit 33 controls the taking lens 20 based on the subject distance detected by the distance measuring unit 4.
The drive amount up to the in-focus position 2 is calculated, and the calculation result is input to the imaging control unit 22 as a drive control signal. The focus control unit 222 drives the electric motor 21 based on the drive control signal input from the control unit 33 to
To automatically adjust the focus.

The scanning control unit 222 controls the order of capturing the partial images in the high resolution mode, that is, the operation of changing the direction of the optical axis of the image capturing unit 2. The direction of each optical axis L (that is, the amount of movement in the horizontal / vertical direction with respect to the front direction of the housing 201) in capturing the partial image is also set in advance according to the number of partial images (that is, the number of divisions N of the subject). I have. In the example of FIG. 4, the direction of the optical axis L of the imaging unit 2 is scanned in a U-shape in the order of acdb, but the scanning direction is not limited to this, and adbd- c and a-c-b-d
And any other scanning method can be adopted. The scanning control unit 222 sets the direction of the optical axis L for each partial image and the scanning direction based on the input information on the number of divisions N of the subject, and drives the electric motors 18 and 19 based on the direction of the optical axis L. To set the field of view of the imaging unit 2 in a predetermined direction.

The CCD control section 224 controls the image pickup operation (charge accumulation and readout of accumulated charges) of the image pickup element 203 (hereinafter, referred to as CCD 203). In a photographing standby state, the CCD control unit 224 drives the CCD 203 to perform video driving so as to capture an image for a finder (the imaging operation is repeated every 1/30 second). In the normal shooting mode, the imaging operation of the CCD 203 is performed only once based on the control signal of the shooting timing input from the control unit 33. In the high resolution mode, the shooting timing input from the control unit 33 is set. CCD2 based on the control signal of
The imaging operation of No. 03 is continuously performed a predetermined number of times ((N + 1) times with respect to the number of divisions N of the subject input from the control unit 2).

The A / D converter 23 converts an image signal (analog signal) output from the image pickup unit 2 into a digital signal of, for example, an 8-bit configuration (hereinafter, this image signal is referred to as image data). . The image processing unit 24 performs predetermined image processing such as γ correction and WB adjustment on image data. The image processing unit 24 has an image memory for temporarily storing image data, and performs predetermined image processing of the image data using the image memory. When displaying a preview image on the LCD display unit 12 or displaying an entire image captured in the high-resolution mode on the monitor, the image data temporarily stored in the image memory of the image processing unit 24 is an LC
The data is output to the D drive unit 28 and displayed on the LCD display unit 12.

The switch circuit 25 switches the output destination of the image data of the image photographed in the recording mode.
The image photographed in the recording mode is subjected to predetermined image processing in image processing 24 and then recorded on the memory card 10. The image photographed in the normal photographing mode or the whole image photographed in the high-resolution mode Is transferred to the memory card 10 as it is and recorded in a predetermined recording area 1. The image data of the partial image photographed in the high-resolution mode is level-converted by the gradation conversion unit 26 so as to reduce the number of gradations (that is, to reduce the number of data). The data is transferred and recorded in a predetermined recording area 2.

Therefore, the switch circuit 25 switches the output destination of the image data of the image photographed in the normal photographing mode or the whole image photographed in the high-resolution mode to the memory card 10 based on the control signal from the control section 33. Then, the output destination of the image data of the partial image photographed in the high resolution mode is switched and set to the gradation conversion unit 26.

The gradation conversion section 26 converts the level of the image data of the partial image photographed in the high resolution mode so as to reduce the number of gradations. In the high resolution mode, (N + 1) images are taken in with respect to the division number N.
, The number of images that can be recorded on the memory card 10 is 1 / (N + 1) as compared with the case of shooting in the normal shooting mode.
And the memory efficiency is considerably reduced.
Therefore, in the digital camera 1 according to the present invention, the number of pieces of image data of the partial images captured in the high-resolution mode is reduced to increase the memory efficiency as much as possible.

FIGS. 7 and 8 are diagrams for explaining a method for reducing the number of image data of a partial image.

As shown in FIG. 7, in the high resolution mode, the screen B _i of the part of the subject is compared with the screen B _{0 of the} whole subject.
(I = 1 to 16) and a total of 17 images are taken. Further, the total number of pixels of the CCD 203 is n (vertical).
× m (horizontal), and the pixel at the i-th row and the j-th column is represented by g (i, j).

When photographing the screen Bi of each part of the subject, each screen Bi is magnified 4 × 4 times so as to have substantially the same size as the screen B _{0 of the} entire subject. The position of the subject projected on the pixel g (k, h) when capturing ₀ is projected on 16 pixels g (p, q) when capturing the partial screen Bi. For example, taking a pixel g (n, 1) as an example, the position of the object to be projected to the pixel g (n, 1) when taking screen B ₀ of the entire subject, the portion as shown in FIG. 7 pixel g at the time of shooting the screen _{B 13 (p, q) (} p
= N-3 to n, q = 1 to 4).

That is, in the case of capturing a partial image, the luminance information of the same position of the subject captured in capturing the entire image
Since the light is magnified twice and received by each of the 16 pixels,
The luminance difference between these pixels is small, and pixels g (n−3,1), g
(n-3,2), g (n-3,3), g (n-3,4),... g (n, 1), g (n,
2), g (n, 3), and g (n, 4) are in a range of gradations narrower than 256 gradations with respect to the level of the pixel g (n, 1) captured in capturing the entire image. Are distributed.

Accordingly, the gradation conversion section 26 reduces the number of gradations of the pixel data constituting the partial image from the gradation number of the pixel data constituting the entire image, thereby reducing the number of data of the partial image to the data of the entire image. Therefore, the number of data of a plurality of images captured in the high-resolution mode is reduced as much as possible.

More specifically, the gradation conversion unit 26 sets the level of the pixel g (k, h) captured in capturing the entire image to D ₀ ,
The level of each of the 16 pixels g (p, q) obtained by receiving light at the same position as the pixel g (k, h) in capturing the partial image is represented by D _ij (i = 1
To 4, when j = 1 to 4) to the level D _ij level D _ij obtained by subtracting the level D ₀ from the level D _ij of each pixel as shown in FIG. 8 g (p, q) ' ( = D _ij -D ₀ ).

FIG. 9 shows a specific example in which level conversion is performed by the gradation conversion section 26 when D ₀ = 100.
In this example, the level D _ij of each of the 16 pixels g (p, q) captured in 256 (= 2 ⁸ ) gradations is converted into a level D _ij ′ in the range of −32 to +32. If these levels D _ij ′ are expressed in binary including the sign, they can be displayed in 6 bits, so that the number of gradations of each pixel g (p, q) is reduced from 8 bits to 6 bits. Become.

Accordingly, if all the image data of the partial image is converted into 6-bit data, the storage capacity of the image taken in the high resolution mode in the memory card 10 is 8 bits × n unless level conversion is performed. × mx17 = 136
When the level is converted, (8 bits ×
n × m × 1) + (6 bits × n × m × 16) = 10
Since it is 4 nm bits, (136-104) × 100
/136≒23.5%.

It is to be noted that a subject generally has a feature that a change in luminance of an adjacent portion is small, and that a photographing lens has a higher MTF (Modulation Transfe) as a spatial frequency becomes higher.
r function) is reduced, so that even if the number of divisions N is reduced, the luminance difference between adjacent pixels of image data taken in when capturing a partial image is small, and the gradation of pixel data constituting the partial image is small. The number can be made smaller than the number of gradations of the pixel data constituting the entire image.

When the number of gradations of the pixel data constituting the partial image is reduced, the MTF is reduced (in the above-described example, MTF = 64 gradations / 256 gradations = 0.2 gradations).
5) Since human visual characteristics have a characteristic that the sensitivity to contrast decreases as the spatial frequency increases, the number of gradations of pixel data constituting a partial image photographed in the high resolution mode is set to the whole image. Even if it is reduced, the effect on the image quality of the high-definition photographed image obtained by synthesizing the partial images is small, and it is considered that there is no particular problem.

Returning to FIG. 6, the recording / reading control section 27 controls the driving of the memory card 10 when recording or reading out a photographed image.

When the partial image recorded in the high resolution mode is transferred to the personal computer when the partial image recorded in the high-resolution mode is transferred to the personal computer, the level of the pixel data constituting the partial image is converted to the original gradation number. The inverse conversion is performed so as to obtain the number of gradations. More specifically, D ₀ is added to the level D _ij ′ of each pixel g (p, q) to perform an inverse conversion to the level D _ij (see the inverse conversion processing in FIG. 8).

The recording / reading control unit 28
This controls the recording and reading of image data to and from a computer. The LCD drive unit 29 controls the driving of the LCD display unit 12 and displays a captured image on a monitor. The LCD drive unit 29 controls the light emission at each pixel position of the LCD display unit 12 based on the pixel data input from the image processing unit 23 or the image data input from the memory card 10 and displays an image on the LCD display unit 12. Let it.

The communication I / F 30 is an interface for controlling data communication with a personal computer connected to the connection terminal 11 via a dedicated cable. RAM (Random Acces)
s Memory) 31 is a memory for the control unit 33 to perform arithmetic processing relating to photographing. ROM (Read Only Me)
(mory) 32 is a memory in which a processing program relating to shooting control, data necessary for drive control of the imaging unit 2 and the like are stored.

Next, the photographing operation of the digital camera 1 will be described with reference to the flowcharts of FIGS.

FIG. 10 is a flowchart showing a photographing operation procedure in the recording mode. FIG. 11 is a flowchart showing a shooting operation procedure in the PC mode.
Note that the flowcharts of FIGS. 10 and 11 show the photographing processing when the high-resolution mode is set. Further, in the description of the photographing process in the high resolution mode, a case where a subject shown in FIG.

When the recording mode is set, the photographing mode, photographing conditions and the like are set or changed in accordance with the settings of the high resolution mode setting button 15 and the number of composite images setting switch 16 (# 2). Further, the imaging unit 2 is driven in the video mode, and the captured image is displayed on the LCD display unit 12 as a monitor (viewfinder display), whereby a photographable state is set (# 4). This state is continued until the shutter button 6 is half-pressed to instruct the preliminary photographing (# 2 to #
6 loop). If the photographer operates the high-resolution mode setting button 15 or the composite image number setting switch 16 during this time, the photographing mode and the photographing conditions are changed according to the operation (# 2).

When the shutter button 6 is half-pressed to instruct preliminary photographing (YES in # 6), first, the photographing direction (the direction of the optical axis L) of the image pickup section 2 is set to the front direction (# 8), the zoom lens 202 of the imaging unit 2 is set to a predetermined wide position (# 10). Subsequently, the subject brightness is detected by the photometry unit 3 (# 12), the subject distance is detected by the distance measurement unit 4 (# 14), and the focus is adjusted based on the subject distance (# 16). Also,
Exposure control values (aperture value and C
The integration time of the CD 203 is set (# 18).

Subsequently, the entire subject is imaged based on the set exposure control value (# 20). A pixel signal constituting a captured image output from the imaging unit 2 is converted into digital pixel data by an A / D conversion unit 22, and after predetermined image processing is performed by an image processing unit 23, the image data is stored in an image memory. Temporarily stored (# 22). The captured image of the entire image is output from the image memory to the LCD drive unit 28,
It is displayed on the D display unit 12 (# 24). With this display, the photographer can monitor the photographed image.

Subsequently, it is determined whether or not the shutter button 6 is fully depressed to give a release instruction (# 2).
6) If the release is not instructed (N in # 26)
O), the process returns to step # 12, and the entire subject is imaged again, and the captured image is temporarily and renewedly recorded on the memory card 10 and displayed on the LCD display unit 12 (# 12).
To # 26 loop).

When the shutter button 6 is fully depressed and a release is instructed (YES in # 26), the flow shifts to step # 28, where a partial image is photographed.

That is, the photographing direction of the image pickup unit 2 is divided into the number of combined images set by the number-of-combined-images setting switch 16, and the first photographing direction when partially photographing the subject (the direction a in FIG. 4). (# 28), and the telephoto position at which the zoom lens 202 of the imaging unit 2 has a predetermined photographing magnification (in the example of FIG. 4, the number of divisions is 4, and the photographing magnification is approximately 2 times). ) (# 30). Then, the upper left portion of the subject is imaged based on the exposure control value set in step # 18 (# 32).

The pixel signals constituting the captured image (partial image) output from the imaging unit 2 are converted into digital pixel data by the A / D conversion unit 23, and then temporarily stored in an image memory in the image processing unit 24. The image is stored and the predetermined image processing is performed by the image processing unit 24 (# 34).

Subsequently, it is determined whether or not the capture of all the partial images has been completed (# 36). If the capture has not been completed (NO in # 36), the process returns to step # 28 to capture the next partial image. . In this case, since the capture of the first partial image has only been completed, the flow returns to step # 28, and the shooting direction of the imaging unit 2 is set to the shooting direction of the second image (the direction c in FIG. 4) (# 28). Then, the zoom lens 202 of the imaging unit 2 is set to a telephoto position (a position approximately twice) at which a predetermined photographing magnification is obtained (# 30), and an upper right portion of the subject is imaged (# 32).

Thereafter, the lower right and lower left partial images of the subject are photographed in the same procedure (# 28 to # 36 loop), and when all the partial images have been captured (YES in # 36), Pixel data constituting each partial image is output to the gradation conversion unit 26 via the switch circuit 25. Each pixel data is converted into corresponding pixel data (pixel data having a relationship of receiving the same subject position) among the pixel data constituting the entire image stored in the memory card 10 from the level value in the gradation conversion unit 26. ) Is subjected to level conversion by a method of subtracting the level value (see the conversion process in FIG. 8), and then output to the memory card 10 and stored in the predetermined storage area 2
(# 38, # 40). This process is performed for all partial images.

Subsequently, it is determined whether or not the still image display is released by the still image display release button 15 (# 4).
2) When the still image display is canceled (YES in # 42),
The process returns to step # 2 to enable the next shooting.

Next, when the PC mode is set, a list of image files stored in the memory card 10 is displayed on the LCD.
The up switch 1 is displayed on the display unit 12 and operated by the operator.
When the image file is selected by operating the down switch 17a or the down switch 17b (# 52), the pixel data of the entire image contained in the selected image file is read out from the storage area 1 of the memory card 10, and the LCD display unit is read. 12 is displayed (# 54, # 56). When the operator operates the confirmation switch 17c to determine the image file to be transferred to the personal computer (YES in # 58), the entire image included in the determined image file from the storage area 1 of the memory card 10 is displayed. The pixel data is read out to the communication I / F 30, and transferred to the personal computer via the communication I / F 30 (# 60, # 62). Subsequently, the pixel data of the partial image is converted from the storage area 2 of the memory card
7 are sequentially read out (# 64), and each pixel data is stored in the gradation inverse conversion unit 27 at the level value of the corresponding pixel data among the pixel data constituting the entire image stored in the memory car 10 at the level value. (# 6) after level conversion by the method of adding the level values of (pixel data having a relationship of receiving the same subject position) (see the inverse conversion processing of FIG. 8).
6), output to the communication I / F 30. Then, the data is transferred to the personal computer via the communication I / F 30 (# 6).
8).

Subsequently, it is determined whether or not the transfer of the pixel data constituting all the partial images to the personal computer has been completed (# 70). If the transfer has not been completed (NO in # 70), the next partial image Then, the process returns to step # 64 to transfer the pixel data of # 1 to the personal computer. In this case, since the transfer of the pixel data of the first partial image has just been completed, step # 64
Then, the process of transferring the pixel data of the second partial image to the personal computer is performed (# 64 to # 70).

Thereafter, the pixel data of the third and fourth partial images is transferred in the same procedure, and when the transfer of the pixel data of all the partial images is completed (YES in # 70),
The process ends.

Note that the personal computer can obtain a high-resolution photographed image by synthesizing the pixel data of the partial image transferred from the digital camera 1 using predetermined image processing software. Then, the operator can view the high-definition photographed image by displaying the composite image on the monitor.

In FIG. 6, a data compression unit is provided between the gradation reverse conversion unit 27 and the communication I / F 30, and the JPE
Data to be transferred may be compressed by a known compression method such as the G method. In this way, the amount of data transferred to the personal computer is reduced, and the transfer speed can be increased.

In the above-described embodiment, the digital camera 1 is provided with the gradation reverse conversion unit 27 so that the gradation number of the pixel data of the partial image is returned to the original gradation number and then transferred to the personal computer. From the digital camera 1 to the gradation reverse conversion unit 2
7 may be removed and the personal computer may return the gradation number of the pixel data of the partial image to the original gradation number. By doing so, the number of data to be transferred to the personal computer is further reduced, so that the data transfer speed from the digital camera 1 to the personal computer can be further increased.

In FIG. 6, an image synthesizing unit for synthesizing a high-definition photographed image by pasting a partial image between the gradation inverse conversion unit 27 and the communication I / F 30 is provided. The captured image may be output to the outside. In this way, there is no need for a process of synthesizing the high-definition photographed image on the personal computer side, and there is an advantage that the high-definition photographed image can be directly viewed by outputting to the monitor TV. The configuration and function of this image synthesizing unit are described in Japanese Patent Laid-Open No. 11-19 / 1999.
Since the same components as those described in JP-A-6299 can be applied, the detailed description is omitted here.

As described above, in the digital camera 1 according to the present embodiment, the level of the pixel data constituting the partial image photographed in the high resolution mode is changed to the same object position among the pixel data constituting the entire image. Is converted by using pixel data having a relationship of receiving light, and the number of gradations is reduced, so that the data capacity of the pixel data constituting the partial image is reduced, and the memory efficiency of the memory card 10 is increased. be able to.

[0088]

As described above, according to the present invention,
Imaging that captures the entire subject, divides the entire subject into multiple parts, captures the images, and combines the captured images of each part based on the entire image to obtain a high-resolution captured image. In the apparatus, the level of each pixel data forming the captured image of each part of the subject is set to the same light receiving position as that of the pixel data so as to reduce the number of gradations of the pixel data forming the captured image of each part of the subject. Since the level conversion is performed using the level of the pixel data forming the captured image of the entire subject in the relationship, the data capacity of the pixel data forming the partial image is reduced, and the memory efficiency of the storage unit can be increased. .

[Brief description of the drawings]

FIG. 1 is a diagram showing an appearance of a digital camera according to an embodiment of the present invention.

FIG. 2 is a rear view of the digital camera according to the present invention.

FIG. 3 is a diagram showing a schematic configuration of an imaging system of the digital camera according to the present invention.

FIG. 4 is a diagram illustrating a relationship between a subject and a shooting range in shooting in a high resolution mode.

FIG. 5 is a diagram for explaining a method of synthesizing partial images shot in a high resolution mode.

FIG. 6 is a block diagram of a digital camera according to an embodiment of the present invention.

FIG. 7 is a diagram showing pixels related to receiving light at the same position of a subject when capturing a partial image with respect to a certain pixel when capturing an entire image.

FIG. 8 is a diagram for explaining a method of level-converting the level of pixel data constituting a partial image so that the number of gradations is reduced.

FIG. 9 is a diagram showing a specific example of a method of level-converting the level of pixel data forming a partial image so that the number of gradations is reduced.

FIG. 10 is a flowchart showing a shooting operation procedure in a recording mode of the digital camera according to the present invention.

FIG. 11 is a flowchart showing a shooting operation procedure in a PC mode of the digital camera according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 digital camera (imaging device) 2 imaging unit 201 housing 202 imaging lens (imaging means) 203 imaging element (imaging means) 3 photometry unit 4 distance measurement unit 5 flash 6 shutter button 7 power switch 8 card insertion slot 9 card ejection Button 10 Memory card (storage means) 11 Connection terminal 12 LCD display unit 13 Mode setting switch 14 Still image display release button 15 High resolution mode setting switch 16 Number of combined images setting switch 17 Image selection switch 18, 19, 20, 21 Electric motor Reference Signs List 22 imaging control unit (imaging control unit) 221 zoom control unit 222 focus control unit 223 scanning control unit 224 CCD control unit 23 A / D conversion unit 24 image processing unit 25 switch circuit 26 gradation conversion unit (level conversion unit) 27th floor Inversion conversion unit 28 Recording / readout control unit 29 CD drive unit 30 communication I / F 31 RAM 32 ROM 33 control unit (storage control unit)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 19/02 G03B 19/02 5C059 H04N 5/225 H04N 5/225 ZF 5/262 5/262 7 / 24 7/13 Z F term (reference) 2H054 AA01 BB11 BB12 2H101 DD00 DD21 DD65 FF00 FF05 FF08 5C022 AA13 AB02 AB15 AB24 AB66 AC03 AC31 AC32 AC42 AC51 AC54 AC69 AC74 AC77 5C023 AA11 AA37 AA38 BA08 BA11 CA01 DA04 EE02 EE03 EE08 GA02 GA03 GA07 GB01 GB05 GC00 GC05 GD03 GE04 GE08 5C059 KK08 LB15 MA02 PP01 PP14 SS14 UA02

Claims (2)

[Claims] 1. An image pickup means having an image pickup surface in which a plurality of pixels are two-dimensionally arranged, and photoelectrically converting an optical image formed on the image pickup surface into an electric signal in each pixel, and a subject light image Image-forming means capable of changing the image magnification for forming an image on the image-capturing surface of the image-capturing means, and imaging the entire object by forming an optical image of the entire object on the image-capturing surface by the image-forming means; The light image of each part obtained by dividing the entire subject into a plurality is enlarged to substantially the same size as the imaging size of the entire subject by the imaging means, and the image is formed on the imaging means. Image capturing control means for capturing an image, and storage means for storing pixel data constituting an image captured by the image capturing means, and combining captured images of respective portions of the subject based on the captured image of the entire subject. High-resolution captured image by combining In the image pickup apparatus capable of creating the image, the level of each pixel data constituting the captured image of each part of the subject is reduced so as to reduce the number of gradations of the pixel data constituting the captured image of each part of the subject. Level conversion means for performing level conversion using the level of the pixel data forming the captured image of the entire subject in which the pixel data and the light receiving position have the same relationship; and the pixel data forming the captured image of the entire subject and the level An image pickup apparatus comprising: a storage control unit configured to store, in the storage unit, pixel data forming a captured image of each portion of the subject whose level has been converted by the conversion unit. 2. The apparatus according to claim 1, wherein the level conversion unit forms a captured image of the entire subject having the same relationship between the pixel data and a light receiving position based on a level value of each pixel data forming the captured image of each portion of the subject. 2. The imaging apparatus according to claim 1, wherein the level conversion is performed to a difference value obtained by subtracting the level value of the pixel data.