JP2003061103A - Image pickup device, adjustment method of white balance, and its operation processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device that attains optimum white balance adjustment of a picture even when it is a moving picture or a still picture. SOLUTION: The image pickup device includes a storage means that stores information associated with a reference white balance control value for photographing a moving picture and a reference white balance control value for photographing a still picture corresponding to the reference white balance control value for photographing the moving picture; an arithmetic means that calculates a white balance control value for photographing a still picture on the basis of the information associated with the reference white balance control value for photographing the moving picture and the reference white balance control value for photographing the still picture corresponding to the reference white balance control value for photographing the moving picture stored in the storage means; and an adjustment means that adjusts the white balance on the basis of the white balance control value for photographing the still picture calculated by the arithmetic means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus capable of picking up a moving image and a still image and having a white balance adjusting operation.

[0002]

2. Description of the Related Art An image pickup device such as a video camera for shooting a moving image or a digital camera for picking up a still image,
A so-called auto white balance function is provided to automatically adjust the output ratio of the RGB signals so that stable and good color reproduction can be obtained even when the color temperature of the light source changes. The auto white balance function generally reads color information of an image to be picked up in order to generate a video signal by subjecting an electric signal from an image pickup device to signal processing, and detects a white object from the picked up image. Detect and adjust the white balance of the captured image.

Normally, the white balance is adjusted so that a white object looks white, but it may be better to slightly shift the white balance. For example, it is more natural to make white look faithfully white in the sun in the outdoors under the sunlight, but in the shade, it is better to slightly shift the white balance adjustment in the blue direction. Also, under an incandescent lamp indoors, the warmth of an incandescent lamp can be obtained by slightly shifting the white balance adjustment in the red / yellow direction.

[0004]

In recent years, some image pickup devices such as video cameras and digital cameras can pick up both moving images and still images. In the case of a video camera, for example, moving images are recorded on a magnetic tape such as 8 mm or DV (Digital Video) tape, and still images are recorded on a semiconductor memory such as a multimedia card (MMC). It Different recording media naturally have different media for reproducing recorded images. If it is a moving image recorded on a tape, it is reproduced on a TV monitor, and if it is a still image recorded on a memory, it is displayed on a monitor for a personal computer or printed on paper by a printer.

Since these media have various recording and reproducing methods (or outputting methods) of images, the same images are obtained by the same lens and the same image pickup device and the same signal processing is performed. As a result, the color reproducibility is different. For example, as described above, if the white balance for moving image shooting is adjusted with some deviation from a value that is considered appropriate in the case of shade or indoors, for example, color reproduction does not improve when a still image is printed. It will be.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to perform optimum white balance adjustment regardless of whether it is a moving image or a still image.

[0007]

In order to achieve the above-mentioned object, according to the present invention, a reference white balance control value for moving image shooting and a standard still image shooting value corresponding to the control value. A holding unit that holds information about the white balance control value, and information about the white balance control value used for shooting the moving image when the moving image shooting is switched to the still image shooting, and a reference moving image that is held by the holding unit. Calculating means for calculating a white balance control value for still image shooting based on information about a white balance control value for shooting and a reference white balance control value for still image shooting corresponding to the control value; Adjusting the white balance based on the white balance control value for still image shooting calculated by To provide an imaging apparatus characterized by having means.

According to another invention of the present application, switching means for switching recording destinations of photographed images for first and second recording media having different recording formats, and the photographing according to the switching of the switching means. An image pickup apparatus, comprising: a control unit that changes white balance adjustment processing of an image.

Further, according to another invention of the present application, when the moving image shooting is switched to the still image shooting, information on the white balance control value used for the moving image shooting, and
The white balance control value for still image shooting based on the previously stored reference white balance control value for moving image shooting and the reference white balance control value for still image shooting corresponding to the control value. And adjusting the white balance based on the white balance control value for still image shooting calculated by the calculating means.

According to another invention of the present application, the white balance adjustment processing of the photographed image is changed in accordance with the switching of the recording destination of the photographed image for the first and second recording media having different recording formats. A white balance adjusting method is provided.

Further, according to another invention of the present application, when the moving image shooting is switched to the still image shooting, information on the white balance control value used for the moving image shooting, and
The white balance control value for still image shooting based on the previously stored reference white balance control value for moving image shooting and the reference white balance control value for still image shooting corresponding to the control value. Is provided, and the white balance is adjusted on the basis of the white balance control value for still image shooting calculated by the calculating means.

According to another invention of the present application, the white balance adjustment processing of the photographed image is changed in accordance with the switching of the recording destination of the photographed image on the first and second recording media having different recording formats. An operation processing program for white balance is provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a block diagram of an image pickup apparatus of the present invention.

The image pickup apparatus according to the present embodiment is provided with a lens 11 on which object light is incident, a diaphragm 12 for adjusting the amount of light,
Image pickup device 13 such as CCD for converting incident light into an electric signal, sample hold and AGC circuit 14 for performing sample hold and gain adjustment for an image signal output from the image pickup device 13, sample hold・ AGC circuit 14
A / D conversion circuit 15 for performing analog-digital conversion (hereinafter referred to as A / D conversion) on the image signal output from the A / D conversion circuit 15, and white for the image signal output from the A / D conversion circuit 15. A signal processing circuit 16 and a signal processing circuit 1 that perform processing such as balance adjustment, gamma correction, and edge enhancement.
A memory composed of a compression / expansion circuit 17 for compressing / expanding the image signal output from 6 using a predetermined process, a semiconductor memory for recording the image signal compressed in the image compression / expansion circuit 17, and the like. A card 18, an image display unit 19 including an LCD monitor for actually displaying an image signal, a white balance control circuit 20 for calculating a white balance control value based on an image signal obtained from the signal processing circuit 16, A system control circuit 21 having a white balance control circuit 20 for controlling the entire image pickup apparatus and a still image switch 24 for instructing recording of a still image.

The amount of light from the subject received by the lens 11 is adjusted by the diaphragm 12, and is imaged on the image pickup element surface of the image pickup element 13. Here, after being converted into an electrical signal, A / A is passed through the sample hold / AGC unit 14.
The signal is A / D converted by the D converter 15 and input to the signal processing circuit 16. In the signal processing circuit 16, the input signal is subjected to processing such as aperture correction, gamma correction and white balance adjustment for each luminance and color component to generate a video signal, which is output to the liquid crystal monitor 19 as a moving image. . When the still image switch is pressed, the image compression / expansion circuit 17 processes the still image into a file format such as a JPEG file, and the still image is recorded in the memory card 18.

The white balance control circuit 20 reads out, for each field, color information relating to a video signal necessary for white balance adjustment from the video signal processing section 16. An image signal recognized as a white subject is extracted from the captured image based on the read color information, and a control value for white balance adjustment is calculated. The control value is data for varying the gain of the image signal (RGB signal) output from the A / D converter 15 in the signal processing circuit 16. White balance control circuit 20
Stores and holds information such as a table described below used for adjusting the white balance. In the present embodiment, the gain of G is fixed and the R value and B
The white balance is adjusted by changing the signal gain.

FIG. 6 is a flowchart of the operation processing for white balance adjustment by the system control circuit 21 in the present embodiment. The white balance adjustment operation of the present embodiment will be described with reference to FIG.

In this embodiment, the system control unit 21 controls each unit so as to generate a moving image immediately after the activation of the electronic still camera. Then, when the still image switch 24 is turned on by a user operation, the system control circuit 21 controls each unit so as to generate a still image only for a predetermined period.

First, in step S101, when the main body of the electronic still camera is activated, the operation of picking up a moving image to be displayed on the image display unit 19 is started. Corresponding to the image capturing operation, white balance adjustment for capturing the captured moving image is performed. The white balance is adjusted by the white balance control circuit 20. The white balance control circuit 20 receives the color information of the photographed image from the video signal processing unit 16 and the brightness information of the subject read out.
Alternatively, what kind of light source the subject is under is determined from the current value of the white balance control value and the like, and the white balance is adjusted by the light source. Specifically, when it is determined that it is an outdoor sun, the neutral color is adjusted. When it is determined that the shade is outdoors, the gain of the B signal is increased from the neutral state to adjust the color to have a cold color tendency. Further, when it is determined that the room is under an incandescent lamp indoors, the gain of the R signal is increased from that in the neutral state so that the color tends to be warm. Here, the neutral coloring means that white appears faithfully white in the finally generated video signal, that is, a state in which the signal levels of the color signals R and B components of the white subject portion are zero.

In step S102, it is determined whether the still image switch 24 has been turned on. If it is turned on, the process proceeds to step S103, and if it is not turned on, the process of step S101 is continued.

In step S103, when the still image switch 24 is turned on, a white balance adjusting operation for still image shooting described later is performed.

In step S104, it is determined whether a predetermined time has elapsed. When the predetermined time has elapsed, the process returns to step S101, and the white balance adjustment operation for moving image shooting is performed again. If the predetermined time has not elapsed, it is determined that the still image capturing operation has not ended, and the process of step S103 is continued.

Here, the white balance adjustment operation for still image photographing in step S103 will be described with reference to FIGS. 2 to 5 showing the correlation of the gain (white balance control value) with respect to the R signal and the B signal.

2 to 5, W1 and W2 are reference white balance control values, and Wn is a moving image white balance control value Wn immediately before the white balance adjusting operation for still image shooting is performed. ing.

W1s is W as shown in FIG.
1, the offset Or1, with respect to the gain of the R signal
It is a white balance control value obtained by shifting the gain of the B signal by the offset Ob1. Further, W2s is a white balance control value obtained by shifting the gain of the R signal by an offset Or2 and the gain of the B signal by an offset Ob2, as shown in FIG.

Here, Or1, Ob1, Or2, Ob2
Is an arbitrary value set in advance. For these values, the white balance control value used for movie shooting is W
When n = W1 or Wn = W2, how much to shift the state of white balance adjustment for still images with respect to W1 and W2 is experimentally determined in advance in a factory or the like and determined.

Wns is finally obtained by obtaining the white balance control value for still image shooting. As shown in FIG. 5, Wn is offset with respect to R signal gain Orn, B signal. Offset for gain of
It is a white balance control value shifted by bn.

Orn and Obn are W1 and W of the control value Wn.
It is calculated based on the ratio of the relative position to 2. That is, the difference between the control values of the R signal component W1 and W2 is Dr.
12, the difference between the control values of W1 and Wn is Dr1n, and the difference between the control values of W1 and W2 of the B signal component is Db1.
2, if the difference between the control values of W1 and Wn is Db1n,
Dr12, Dr1n, Db12, Db1n for Or1, Ob1, Or2, Ob2, Orn, Obn are (Orn-Or1) / (Or2-Or1) = Dr1n / Dr12 (Equation 1) (Obn-Ob1) / (Ob2). -Ob1) = Db1n / Db12 ... (Formula 2). Orn and Obn are calculated as a result of the calculation using these (Equation 1) and (Equation 2). Therefore, the white balance control value Wn held in advance before the still image shooting is performed.
Or calculated using (Equation 1) and (Equation 2) for
By shifting by n and Obn, the white balance control value Wns for still image shooting can be obtained.

As described above, by correcting the white balance control value for shooting a moving image, it is possible to perform an appropriate white balance control for a still image.

(Second Embodiment) The second embodiment of the present invention will be described below.

FIG. 7 is a block diagram of an image pickup apparatus according to the second embodiment.

The image pickup apparatus of the present embodiment has a memory card 18 composed of a magnetic tape 23 and a semiconductor memory as a storage medium, and a recording medium to be recorded according to the operation of the tape / memory card changeover switch 25. Is switched by the internal switch 26. Further, the image pickup apparatus according to the present embodiment can record only a still image on the memory card 23 and record a still image on the magnetic tape 18 by operating the moving image switch 26. And The compression / expansion circuit 22 is a circuit that compresses and expands an image to be recorded on the magnetic tape 23 in a TV signal format such as NTSC, and digitizes the image into a predetermined format. That is, the still image recorded in the file format on the memory card 18 and the still image recorded on the magnetic tape 23 have different recording formats. Further, the other reference numerals which are the same as those in FIG. 1 indicate the same configurations as those in FIG.

In the processing of this embodiment, only when the still image is taken and the memory card 18 is selected as the recording medium by the switching operation of the tape / memory card changeover switch 25, It is assumed that the white balance adjustment for still image shooting in step S103 of 6 is performed. That is, in the white balance adjustment processing of the second embodiment, step S1 of FIG.
In the process of 02, only when the memory card 18 is selected as the recording medium when the still image switch 24 is turned on, the process proceeds to the white balance adjustment process of step S103. If the magnetic tape 23 is selected as the recording medium, the white balance adjustment processing of step S101 is continued regardless of whether moving image recording or still image recording is performed.

Such processing considers that the still image recorded in the memory card 18 is most likely to be printed out by a printer or the like, and the white balance adjustment processing can be further improved. .

In each of the embodiments, the reference white balance control values W1 and W2 are not limited, and the number of reference white balance control values is not limited.

In the present invention, as an example, the program code of software for realizing the functions of the above-described embodiment is
It is supplied to the imaging device via a network such as the Internet, and the computer (or CPU or MP
U) can be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the function of the white balance control circuit 20 of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. It will be.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, C
A D-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a ROM, etc. can be used.

Further, not only the functions of the above-described embodiments are realized by executing the program code read by the computer, but also the OS (operating system) running on the computer based on the instructions of the program code. ) And the like perform some or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Furthermore, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, A CPU or the like included in the function expansion board or the function expansion unit performs a part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the above-mentioned storage medium, the storage medium stores the program code corresponding to the above-mentioned flow chart, but briefly, it is indispensable for the image pickup apparatus of the present invention. Various modules
It will be stored in a storage medium.

[0043]

As described above, according to the present invention, it is possible to appropriately adjust the white balance according to the use of the captured image and the moving image and still image having different viewing means or the recording medium for recording the image. You can

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic still camera according to a first embodiment.

FIG. 2 is a diagram showing a correlation of a gain (white balance control value) with respect to an R signal and a B signal.

FIG. 3 is a diagram showing a correlation of a gain (white balance control value) with respect to an R signal and a B signal.

FIG. 4 is a diagram showing a correlation of a gain (white balance control value) with respect to an R signal and a B signal.

FIG. 5 is a diagram showing a correlation of a gain (white balance control value) with respect to an R signal and a B signal.

FIG. 6 is a flowchart of an operation process of white balance adjustment according to the present invention.

FIG. 7 is a block diagram of a video camera according to a second embodiment.

[Explanation of symbols]

13 Image sensor 16 Signal processing circuit 18 memory card 19 Image display section 20 White balance control circuit 21 System control circuit 24 Still image switch 25 magnetic tape

Claims (27)

[Claims] 1. A holding unit for holding a reference white balance control value for a moving image and information about a reference white balance control value for a still image corresponding to the control value, and switching from moving image shooting to still image shooting. Information about the white balance control value used to shoot the video,
And a white balance control for a still image based on the reference white balance control value for a moving image and the reference white balance control value for a still image corresponding to the control value held by the holding unit. An image pickup apparatus comprising: a calculating unit that calculates a value; and an adjusting unit that adjusts the white balance based on the white balance control value for a still image calculated by the calculating unit. 2. The method according to claim 1, further comprising first and second recording means for recording a still image.
The image pickup apparatus, wherein the calculation is performed by the calculation means only when a still image is recorded in the recording means. 3. The image pickup device according to claim 2, wherein the first recording unit records on a semiconductor memory and the second recording unit records on a magnetic tape. 4. The white balance control for a still image according to claim 1, when the moving image shooting is switched to the still image shooting, the calculating means is based on information about white balance control data used for immediately preceding moving image shooting. An image pickup device characterized by calculating a value. 5. The white balance control according to claim 1, wherein the holding unit holds at least two reference white balance control values for a moving image, and the white balance control used for the moving image shooting with respect to these two control values. An image pickup apparatus, wherein a white balance control value for a still image is calculated based on a relative position of the values. 6. The light source according to claim 1, wherein the reference white balance control value for a still image held by the holding unit uses a white balance control value for a moving image which is a reference for moving image shooting. The image pickup device is set in the color temperature state of. 7. A switching unit for switching a recording destination of a captured image to first and second recording media having different recording formats, and a white balance adjustment process of the captured image is changed according to switching of the switching unit. And a control unit for controlling the imaging device. 8. The image pickup device according to claim 7, wherein one of the first and second recording media records an image in a file format. 9. The image pickup device according to claim 7, wherein the first recording medium is a semiconductor memory, and the second recording medium is a magnetic tape. 10. When switching from moving image shooting to still image shooting, information about a white balance control value used for moving image shooting, and a white balance control value for a moving image serving as a reference that is held in advance and its control value. The white balance control value for a still image is calculated based on the information about the white balance control value for a still image, which is a reference corresponding to, and based on the white balance control value for a still image calculated by the calculating means. A white balance adjusting method characterized by adjusting white balance. 11. The calculation for the still image according to claim 10, of the first and second recording means for recording the still image, only when the still image is recorded in the first recording means. A white balance adjustment method characterized by performing. 12. The white balance adjusting method according to claim 11, wherein the first recording unit is a semiconductor memory and the second recording unit is a magnetic tape. 13. The white balance control value for a still image according to claim 10, when the video shooting is switched to the still image shooting, the white balance control value for the still image is calculated based on the information about the white balance control data used for the immediately preceding video shooting. White balance adjustment method characterized by. 14. The method according to claim 10, wherein at least two white balance control values for a moving image serving as a reference are held in advance, and a relative position of the white balance control value used for shooting the moving image with respect to these two control values is held. A white balance adjustment method that calculates the white balance control value for still images based on this. 15. The light source according to claim 10, wherein the reference white balance control value for a still image held by the holding unit uses a white balance control value for a moving image which is a reference for moving image shooting. The white balance adjustment method, which is set in the color temperature state of. 16. A white balance adjustment process for changing the white balance of a captured image according to switching of recording destinations of the captured image for first and second recording media having different recording formats from each other. Adjustment method. 17. The first and second devices according to claim 16.
One of the recording media is a white balance adjustment method, in which an image is recorded in a file format. 18. The white balance adjusting method according to claim 16, wherein the first recording medium is a semiconductor memory, and the second recording medium is a magnetic tape. 19. When switching from moving image shooting to still image shooting, information about a white balance control value used for moving image shooting, and a white balance control value for a moving image serving as a reference that is held in advance and its control value. The white balance control value for a still image is calculated based on the information about the white balance control value for a still image, which is a reference corresponding to, and based on the white balance control value for a still image calculated by the calculating means. An operation processing program characterized by adjusting white balance. 20. The calculation for a still image according to claim 19, of the first and second recording means for recording a still image, only when the still image is recorded in the first recording means. An operation processing program characterized by performing. 21. The operation processing program according to claim 20, wherein the first recording means is a semiconductor memory, and the second recording means is a magnetic tape. 22. The white balance control value for a still image according to claim 19, when the moving image shooting is switched to the still image shooting, the white balance control value for the still image is calculated based on the information about the white balance control data used in the immediately preceding moving image shooting. An operation processing program characterized by. 23. In claim 19, at least two white balance control values for a moving image serving as a reference are held in advance, and the relative position of the white balance control value used for the moving image shooting with respect to these two control values is held. An operation processing program that calculates the white balance control value for a still image based on this. 24. The light source according to claim 19, wherein the reference white balance control value for a still image held by the holding unit uses a white balance control value for a moving image which is a reference for shooting a moving image. An operation processing program, which is set in the color temperature state of. 25. A white balance adjustment process for changing the white balance of a captured image according to switching of recording destinations of the captured image for first and second recording media having different recording formats from each other. Motion processing program. 26. The first and the second according to claim 25.
One of the recording media is a white balance operation processing program, wherein an image is recorded in a file format. 27. The white balance operation processing program according to claim 25, wherein the first recording medium is a semiconductor memory, and the second recording medium is a magnetic tape.