JP2012010238A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent look conversion processing without increasing user burden when look conversion processing is performed to obtain a consistent look at an image under difference observation conditions.SOLUTION: An imaging device includes: an imaging section for photographing a subject and generating an image; an adjustment section for making white balance adjustment to the image generated by the imaging part according to any of a plurality of control modes including an auto mode which automatically calculates a control value; a conversion processing section for applying look conversion process to the image to which white balance adjustment is made in order to obtain a consistent image look under different observation conditions; and a control section for setting a control mode in the adjustment section to the auto mode if look conversion processing is applied when photographing is performed by the imaging section.

Description

  The present invention relates to an imaging apparatus.

  Conventionally, various techniques relating to color matching have been considered. For example, in the invention of Patent Document 1, an image observation condition is calculated from an imaging condition or an output of a photometric sensor, and the calculated observation condition is stored as additional information of the image. The setting is automated to reduce the user load for setting the observation conditions.

JP 2005-354230 A

  By the way, in invention of patent document 1, the illumination white point is used as an adaptation white point. However, an appropriate parameter may not be set depending on the balance with the white balance adjustment that is generally performed. In such a case, as a part of color matching, for example, a so-called appearance conversion process for matching the appearance of images under different observation conditions is performed using set parameters, and a desired result can be obtained for the user. Absent. In order to avoid such a problem, it is necessary to make settings and adjustments as appropriate, resulting in a problem that the load on the user increases.

  The present invention has been made in view of the above problems, and when performing the appearance conversion process for matching the appearance of images under different observation conditions, a suitable appearance conversion process in conjunction with white balance adjustment is applied to the user's load. The goal is to achieve without increasing.

  The image pickup apparatus according to the present invention provides the image generated by the image pickup unit according to any one of an image pickup unit that picks up a subject image and generates an image, and a plurality of control modes including an auto mode that automatically calculates a control value. An adjustment unit that performs white balance adjustment on the image, a conversion processing unit that performs an appearance conversion process for matching the appearance of images under different observation conditions, with respect to the image on which the white balance adjustment has been performed by the adjustment unit, A control unit configured to set the control mode in the adjustment unit to the auto mode when the appearance conversion process is performed during imaging by the imaging unit;

  The control unit may prohibit the change from the auto mode to another control mode with respect to the control mode in the adjustment unit when the appearance conversion process is performed during imaging by the imaging unit. .

  Further, the control unit performs the white balance adjustment according to the auto mode, and performs the white balance adjustment according to the auto mode when performing the appearance conversion process at the time of imaging by the photographing unit, In addition, as compared with the case where the appearance conversion process is not performed during imaging by the imaging unit, white adaptation in at least one of the low color temperature unit and the high color temperature unit is performed with respect to the white balance adjustment by the white balance adjustment unit. The degree may be increased.

  According to the present invention, it is possible to realize suitable appearance conversion processing linked with white balance adjustment without increasing the user's load when performing appearance conversion processing for matching the appearance of images under different observation conditions. .

It is a conceptual diagram of an appearance conversion process. It is a figure explaining a stimulus, a background, and three surrounding areas. It is a block diagram which shows the structure of the electronic camera 1 of embodiment. It is a flowchart explaining operation | movement of the control part 18 at the time of imaging | photography. It is a figure explaining the parameter determination of white balance adjustment. It is another figure explaining the parameter determination of white balance adjustment.

  First, an appearance conversion process for matching the appearance of images under different observation conditions in color matching will be described. FIG. 1 is a conceptual diagram of appearance conversion processing.

  As shown in FIG. 1, first, Scene Colorimetry is performed on an input image. In Scene Colorimetry, for example, an input image is converted into an XYZ color space under the white point of the shooting scene. Next, Appearance conversion is performed. In Appearance conversion, data is converted into a color space that does not depend on viewing conditions. Generally, a human color perception model is used. A typical color perception model is CIECAM02. Next, Output Colorimetry is performed. In Output Colorimetry, conversion to an output color space chromaticity value (for example, sRGB) is performed. Then, conversion to Output-Referenced is performed. In the conversion to Output-Refered, conversion according to preferable color reproduction, conversion according to the color gamut of the output device, and the like are performed.

In these processes, an imaging observation parameter related to input and an output observation parameter related to output are required. An example of the imaging observation parameter and the output observation parameter used in the above-described CIECAM02 is given below.
1) Adapting white point (Xw, Yw, Zw)
The adaptation white point indicates the white point of the adaptation region, and more simply indicates the illumination white point.
2) Adaptation luminance La [cd / m ^ 2]
The adaptation brightness La [cd / m ^ 2] is also called scene brightness and indicates the absolute brightness of the adaptation area.
3) Ambient brightness c
Ambient brightness c indicates a ratio of brightness between the surrounding area and the adaptation area. When the brightness of the surrounding area is equal to or higher than the brightness of the adaptation area, it is classified as Average, and as the brightness of the adaptation area becomes darker, it is classified as Dim and Dark respectively.
4) Background luminance Yb
The background luminance Yb indicates 20% of the white point absolute luminance.

  Note that the above-described imaging observation parameter and output observation parameter are calculated by defining three areas, i.e., stimulus, background, and surrounding, as calculation areas. As shown in FIG. 2, for example, a stimulus corresponds to a viewing angle of 2 degrees, a background corresponds to a viewing angle of 10 degrees outside the stimulus, and a surrounding corresponds to the outside of the background.

  Hereinafter, an electronic camera will be described as an example of the imaging apparatus of the present invention.

  FIG. 3 is a block diagram showing a configuration of the electronic camera 1 of the present embodiment.

  As shown in FIG. 3, the electronic camera 1 includes an imaging lens unit 10, an imaging unit 12 including an imaging element 11 such as a CCD, an image processing unit 13 that performs image processing on image data generated by the imaging unit 12, A display unit 14 including a liquid crystal monitor for displaying an image, a recording unit 15 including a recording medium for recording an image, a release button (not shown), and the like, an operation unit 17 for receiving a user operation, and a control for controlling each unit The unit 18 is provided. The imaging unit 12, the image processing unit 13, the recording unit 15, and the control unit 18 are connected to each other via a bus. The outputs of the control unit 18 and the image processing unit 13 are also connected to the display unit 14 via a bus. The output of the operation unit 17 is connected to the control unit 18.

  The imaging unit 12 photoelectrically converts the subject image that has passed through the photographing lens unit 10 by the imaging element 11, further performs A / D conversion, and outputs image data. The image processing unit 13 performs processing such as white balance adjustment, color processing, and gamma processing on the image data acquired by the imaging unit 10. The image processing unit 13 also performs processing related to color matching such as appearance conversion processing on the image data acquired by the imaging unit 10 and the image data recorded in the recording unit 15. The display unit 14 displays the image generated by the image processing unit 13 and the image recorded in the recording unit 15 and also displays a through image for composition confirmation, and is also used as a viewfinder. The control unit 18 includes a memory 19 therein, and stores a program for controlling each unit in advance. And the control part 18 controls each part according to this program. Further, the control unit 18 detects the state of the operation unit 17.

  In the electronic camera 1 having the above-described configuration, when an imaging instruction is issued via the operation unit 17, the control unit 18 detects this, photoelectrically converts the subject image via the photographing lens unit 10 by the imaging element 11, Further, A / D conversion is performed. Then, the control unit 18 performs processing such as white balance adjustment, color processing, and gamma processing via the image processing unit 13 and records them in the recording unit 15.

  The electronic camera 1 has a plurality of control modes including an auto mode for automatically calculating parameters used for white balance adjustment with respect to the above-described white balance adjustment. Control modes other than the auto mode include, for example, a preset mode and a control mode corresponding to the type of light source. The user can select any control mode from a plurality of control modes by a user operation via the operation unit 17.

  Further, the user can switch ON / OFF of the above-described appearance conversion process by a user operation via the operation unit 17.

  Hereinafter, the operation of the control unit 18 at the time of shooting will be described with reference to the flowchart of FIG.

  In step S <b> 1, the control unit 18 determines whether an imaging instruction has been performed. If it is determined that a shooting instruction has been issued, the control unit 18 proceeds to step S2.

  In step S2, the control unit 18 determines whether the appearance conversion process is ON. If it is determined that the appearance conversion process is ON, the control unit 18 proceeds to step S3. On the other hand, when it is determined that the appearance conversion process is not ON (OFF), the control unit 18 proceeds to Step S6 described later.

  In step S3, the control unit 18 determines whether or not the white balance adjustment control mode is set to the auto mode. If it is determined that the auto mode is set, the control unit 18 proceeds to step S5 described later. On the other hand, when determining that the auto mode is not set (a control mode other than the auto mode is set), the control unit 18 proceeds to step S4.

  In step S4, the control unit 18 sets the control mode for white balance adjustment to the auto mode. That is, if the appearance conversion process is ON (step S2 Yes) and the white balance adjustment control mode is set to a control mode other than the auto mode (No in step S3), the control unit 18 is forced. Automatically set to auto mode.

  In the appearance conversion process, it is necessary to use an adaptive white point for parameter calculation. When the white balance adjustment control mode is set to a control mode other than the auto mode, the adaptive white point has a fixed value corresponding to each control mode. For this reason, there is a case where a correct adaptive white point suitable for the appearance conversion process cannot be obtained, and a preferable appearance conversion process cannot be performed with parameters calculated based on such an adaptive white point. Therefore, by setting the white balance adjustment control mode to the auto mode, it is possible to avoid white balance adjustment that does not conform to the state where the appearance conversion process is ON.

  In step S5, the control unit 18 prohibits changing the control mode of white balance adjustment. That is, the control unit 18 maintains a state in which the appearance conversion process is ON (Yes in step S2) and the white balance adjustment control mode is set to the auto mode.

  In step S6, the control unit 18 controls the imaging unit 12 to perform imaging.

  In step S7, the control unit 18 determines white balance adjustment parameters.

  FIG. 5 is a conceptual diagram showing characteristics of white balance adjustment. A curve Ln in FIG. 5 shows the characteristics of white balance adjustment in a general auto mode. In the white balance adjustment in the general auto mode, as shown by the curve Ln in FIG. 5, by setting the white adaptation degree low in the low color temperature part and the high color temperature part, the characteristic color tone is set. The remaining white balance is adjusted. As a result, for example, the sunset can be expressed in red, or the sky can be expressed in blue. However, when the appearance conversion process is ON, if the white balance adjustment is performed with such characteristics, it may not be possible to obtain a correct adaptive white point suitable for the appearance conversion process. Therefore, when the appearance conversion process is ON, white adaptation is set higher than the curve Ln in the low color temperature portion and the high color temperature portion, as shown by the curve L1 in FIG. If the white balance adjustment is performed with such characteristics, a correct adaptation white point suitable for the appearance conversion process can be obtained, and as a result, a preferable appearance conversion process can be realized.

  Note that the curve L1 in FIG. 5 is an example, and is not limited to this example as long as the white adaptation degree in at least one of the low color temperature portion and the high color temperature portion is higher than the curve Ln. For example, the degree of adaptation in either the low color temperature part or the high color temperature part may be higher than that of the curve Ln. Further, as shown by a curve L2 in FIG. 6, the same effect can be obtained even if the range in which the white adaptation is increased is narrower than the curve Ln.

  The control unit 18 determines white balance adjustment parameters for realizing the characteristics described with reference to FIGS. 5 and 6.

  In step S8, the control unit 18 determines the parameters for the appearance conversion process. The control unit 18 determines the parameters of the appearance conversion process as in the known technique.

  In step S9, the control unit 18 controls the image processing unit 13 to perform normal image processing such as white balance adjustment, color processing, and gamma processing. However, the image processing unit 13 uses the parameters determined in step S7 for white balance adjustment, and uses the parameters determined in step S8 for appearance conversion processing.

  In step S10, the control unit 18 records the image subjected to the image processing in step S9 in the recording unit 15.

  As described above, according to the present embodiment, the imaging unit according to one of a plurality of control modes including an imaging unit that captures a subject image and generates an image, and an auto mode that automatically calculates a control value. An adjustment unit that performs white balance adjustment on the image generated by the adjustment unit, and a conversion processing unit that performs appearance conversion processing for matching the appearance of the image under different observation conditions with respect to the image that has been subjected to white balance adjustment by the adjustment unit. In the case where the appearance conversion process is executed during imaging by the imaging unit, the control mode in the adjustment unit is set to the auto mode. Further, according to the present embodiment, when the appearance conversion process is executed during imaging by the imaging unit, the change from the auto mode to another control mode is prohibited with respect to the control mode in the adjustment unit. Accordingly, it is possible to obtain a correct adaptive white point that matches the appearance conversion process. Therefore, when performing the appearance conversion process for matching the appearance of images under different observation conditions, it is possible to realize a suitable appearance conversion process linked with white balance adjustment without increasing the load on the user.

  Further, according to the present embodiment, when performing white balance adjustment according to the auto mode, and when performing appearance conversion processing at the time of imaging by the photographing unit, the white balance adjustment is performed according to the auto mode, and the photographing unit Compared to the case where the appearance conversion process is not executed during imaging, the white adaptability is increased in at least one of the low color temperature portion and the high color temperature portion with respect to the white balance adjustment by the white balance adjustment portion. Therefore, since the correct adaptation white point suitable for the appearance conversion process can be obtained more accurately, the accuracy of the appearance conversion process can be improved.

  In this embodiment, when the appearance conversion process is switched from ON to OFF at an arbitrary timing, the control unit 18 performs the “change of control mode for white balance adjustment” prohibited in step S5 of FIG. to approve. Further, when the auto mode is forcibly set in step S4 in FIG. 4, the control unit 18 returns to the originally set white balance adjustment control mode at the timing when the appearance conversion process is switched off. Settings may be made.

  In the present embodiment, as described with reference to FIG. 4, an example of performing appearance conversion processing determination (step S <b> 2) and white balance adjustment control mode determination (step S <b> 3) after a shooting instruction is performed. However, the present invention is not limited to this example. For example, a part or all of the processing described in steps S2 to S5 in FIG. 4 may be performed while a so-called through image for composition confirmation is being captured at the timing before the imaging instruction.

  In the present embodiment, the electronic camera 1 shown in FIG. 3 has been described as an example, but the present invention is not limited to this example. For example, the present invention can be similarly applied to an electronic camera having a configuration different from the electronic camera 1 illustrated in FIG. 3 such as an electronic camera having a moving image shooting function.

DESCRIPTION OF SYMBOLS 1 ... Electronic camera, 12 ... Imaging part, 13 ... Image processing part, 14 ... Display part, 18 ... Control part

Claims (3)

An imaging unit that captures a subject image and generates an image;
An adjustment unit that performs white balance adjustment on the image generated by the imaging unit according to any of a plurality of control modes including an auto mode that automatically calculates a control value;
A conversion processing unit that performs an appearance conversion process for matching the appearance of an image under different observation conditions with respect to the image that has been subjected to the white balance adjustment by the adjustment unit;
An imaging apparatus comprising: a control unit that sets the control mode in the adjustment unit to the auto mode when the appearance conversion process is executed during imaging by the imaging unit. The imaging device according to claim 1,
The control unit prohibits a change from the auto mode to another control mode with respect to the control mode in the adjustment unit when executing the appearance conversion process at the time of imaging by the imaging unit. Imaging device. In the imaging device according to claim 1 or 2,
The control unit performs the white balance adjustment according to the auto mode, and performs the white balance adjustment according to the auto mode when performing the appearance conversion process at the time of imaging by the photographing unit, and Compared to the case where the appearance conversion process is not executed during imaging by the imaging unit, the white adaptability of at least one of the low color temperature unit and the high color temperature unit is set with respect to the white balance adjustment by the white balance adjustment unit. An imaging device characterized by being raised.

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