JP2014023063A - Imaging device and the control method thereof, image processor and image processing method, program, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device capable of properly performing optical correction corresponding to an exchange type lens unit without the need for a user to particularly being conscious.SOLUTION: A lens exchange type imaging device has acquisition means for acquiring correction data from a mounted lens unit, correction means for performing correction of a signal caused by an optical characteristic of a lens in photographing an image photographed on a predetermined photographing condition, the correction being referred to the acquired correction data, and recording means for recording information and an image corresponding to the correction data acquired by the acquisition means by associating the information with the image.

Description

  The present invention relates to a technique for correcting image deterioration caused by optical characteristics of a lens unit.

  One factor that hinders the improvement in image quality of an image obtained by an imaging device such as a digital camera is image degradation due to the optical characteristics of an imaging lens used to form a subject image. Examples of optical characteristics that cause this image degradation include peripheral light reduction, distortion, and lateral chromatic aberration. Although these optical characteristics vary depending on the optical system of the lens unit, it is difficult to realize an optical system that completely eliminates the optical characteristics that cause image degradation in recent years when the lens unit is required to be downsized. Therefore, there is a technique for correcting such image deterioration by image processing.

  Since it is very difficult to completely extract the optical characteristics of a lens from an image, in order to perform correction by image processing with high accuracy, data indicating the optical characteristics of the imaging optical system is stored in a memory in the camera. There is a method of storing optical correction data used for the correction. In particular, in a single-lens reflex digital camera, it is necessary to store optical correction data of each of a plurality of types of lens units (imaging optical systems) that can be attached to the camera body. Furthermore, even in the same imaging optical system, the optical characteristics change depending on optical parameters such as a focal length, a shooting distance, and an aperture value. Therefore, optical correction data corresponding to a plurality of optical parameters is stored in a memory in the camera, and a correction value that matches the shooting conditions is calculated. In addition, the single lens reflex camera needs to store optical correction data of a plurality of types of lens units as described above. However, if there are many types of lens units that can be mounted, all the lenses will be used with the memory capacity in the camera. It may be difficult to store unit correction data.

  Here, in Patent Document 1, in the camera in which the lens unit can be mounted as described above, the correction data is held on the lens unit side, and the correction data is transferred to the camera side when mounted on the camera. Is described. Patent Document 2 describes a method of preventing excessive correction and unauthorized correction by limiting the correction amount in advance by the user when optical characteristics are corrected on the camera side.

JP 2012-078425 A JP 2010-187183 A

  However, in Patent Document 1, it is possible to transfer optical correction data from the lens unit to the camera. However, the optical correction data has a large amount of data, and the lens unit and the camera are connected via an electrical contact. It is common. Further, there is no mention of processing when developing recorded RAW data.

  Moreover, in the said patent document 2, an excessive correction | amendment and unauthorized correction | amendment can be prevented because a user sets the upper limit of the correction amount in advance. However, the user must manually set the upper limit of the correction value, and in particular, setting the upper limit value for each lens unit is very troublesome and impractical. Further, there is no mention of processing when developing recorded RAW data.

  The present invention has been made in view of the above problems, and an object of the present invention is to realize an imaging apparatus that can appropriately perform optical correction according to an interchangeable lens unit without any particular awareness of the user.

  In order to solve the above problems and achieve the object, an imaging apparatus according to the present invention is an interchangeable lens type imaging apparatus, the acquisition means for acquiring correction data from a mounted lens unit, and the acquisition Correction means referring to the correction data, the correction means for correcting the signal due to the optical characteristics of the lens at the time of shooting of the image shot under the predetermined shooting conditions, and the correction data acquired by the acquisition means Recording means for associating and recording corresponding information and images.

  According to the present invention, the optical correction according to the interchangeable lens unit can be appropriately performed without the user being particularly conscious.

1 is a block diagram showing a configuration of an imaging apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating optical correction data according to the first embodiment. 5 is a flowchart illustrating optical correction value calculation processing according to the first embodiment. 5 is a flowchart illustrating lens data validity determination processing according to the first embodiment. FIG. 3 is a diagram illustrating a data structure of a file in which an optical correction result according to the first embodiment is recorded. 10 is a flowchart illustrating an initial image display process according to the second embodiment. The figure which illustrates the application screen of Embodiment 2.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. The embodiment described below is an example for realizing the present invention, and should be appropriately modified or changed according to the configuration and various conditions of the apparatus to which the present invention is applied. It is not limited to the embodiment. Moreover, you may comprise combining suitably one part of each embodiment mentioned later.

  [Embodiment 1] An embodiment in which the present invention is applied to an image pickup apparatus such as a digital camera for taking a still image or a moving image will be described below.

  <Apparatus Configuration> With reference to FIG. 1, an outline of the configuration and functions of an imaging apparatus according to an embodiment of the present invention will be described.

  In the imaging apparatus shown in FIG. 1, a lens unit 101 is attached to the camera body 100, and a subject image (not shown) is formed on the imaging element 102 of the camera body 100 by the imaging optical system of the lens unit 101. The aperture 101a constituting the imaging optical system has an aperture diameter controlled as an F-number imaging state setting. Further, the focus lens 101b constituting the imaging optical system is controlled in position by an unillustrated autofocus (AF) mechanism or manual manual focus mechanism in order to perform focusing according to the distance of the subject. The in-lens unit storage unit 101c is a non-volatile memory that holds optical correction data necessary for correcting image degradation due to optical characteristics by image processing.

  The lens unit 101 can be attached to and detached from the camera body 100 and can be replaced with another lens unit. The subject image is converted into an electric signal by the image sensor 102, converted into a digital signal by the A / D conversion unit 103, and input to the image processing unit 104. The image processing unit 104 includes an optical correction unit 111 and an other image processing unit 112 that performs predetermined image processing. The optical correction unit 111 corrects image degradation due to the optical characteristics of the lenses of the imaging optical system by image processing. In addition, the image processing unit 112 performs a series of development processing such as pixel interpolation processing, luminance signal processing, and color signal processing. The order of processing in the optical correction unit 111 and the other image processing unit 112 may be switched according to the characteristics of optical correction. The optical correction processing in the present embodiment means all image deterioration processing caused by the imaging optical system such as peripheral light amount, magnification chromatic aberration correction, distortion aberration correction, and the like.

  The lens unit controller 106 controls the lens unit 101 and performs data communication. The state detection unit 107 obtains various types of information regarding imaging conditions such as a focal length, an imaging distance, and an aperture value of the imaging optical system through the lens unit control unit 106. In addition, the lens unit control unit 106 acquires the optical correction data held in the lens unit storage unit 101 c in the lens unit 101 and stores it in the storage unit 108. The timing of acquiring the optical correction data from the lens unit 101 may be at the time of starting the apparatus, or may be every time if the processing is in time.

  When data is transferred from the lens unit 101 to the camera body 100 as in the present embodiment, activation or shooting cannot be performed unless communication is completed. Therefore, in order to shorten the time until activation and shooting, the amount of data is as much as possible. It is desirable to reduce it. However, since various types of lens units such as a zoom lens, a single focus lens, and a macro lens may be mounted, it is desirable to transfer optical correction data of an optimal size for each lens unit.

  Here, the data structure of the optical correction data transferred from the lens unit 101 to the camera body 100 will be described with reference to FIG. As shown in FIG. 2, the optical correction data is composed of a header area a and a correction storage area b. The header area a is recorded with the ID of the target lens unit at the head, and includes a division point number storage area a1, a focal length information number storage area a2, and a division point information storage area a3.

  Rather than holding correction values corresponding to all optical parameters such as focal length, shooting distance, and aperture value obtained at the time of shooting as optical correction data, the above optical parameters are divided and selected discretely, and the target optical parameters Only the correction value corresponding to is stored as optical correction data.

  The division point storage area a1 is an area for recording the number of division points for discretely holding each parameter. For example, when the target lens unit is a zoom lens, the focal length division number zNum in the division point storage area a1 holds division point data when the focal length from Tele to Wide is divided by zNum. Specifically, when the lens unit has a Wide end of 28 mm and a Tele end of 200 mm, if zNum is 4, data of the number of divisions obtained by dividing 28 mm and 200 mm into four (for example, 28 mm 50 mm 100 mm 200 mm) is held. It is desirable that the number of divisions and the division points have optimum values for each lens unit.

  Although the number of division points of the focal length has been described here, the same applies not only to the focal length but also to the shooting distance and the aperture, and the number of division points according to the optical characteristics for each parameter can be set.

  The focal length information count storage area a2 holds information for variably setting the shooting distance and the aperture dividing point according to the focal length. Some zoom lens type lens units change the open Fno and the shortest shooting distance by changing the zoom position. The focal length-specific aperture information zfNum indicates the number of minimum aperture values for setting the minimum aperture value for each of the focal length division numbers zNum set in the division point number storage area a1. In this way, the correction accuracy can be improved by maintaining the minimum aperture value for each focal length division position. Of course, since it is not necessary to hold a lens unit whose open Fno does not change according to the focal length, data can be reduced if 0 is described.

  Here, the number of aperture information by focal length zfNum has been described as an example, but the number of imaging distance information by focal length zdNum can be considered in the same manner.

  In the division point information storage area a3, information on the division points set in the division point number storage area a1 and the focal distance information number storage area a2 is described. For example, in the case of the lens unit of 28-200 mm which is the example described above, the divided four points (28 mm 50 mm 100 mm 200 mm) are stored in z [0] to z [3]. Hereinafter, similarly, aperture division information, shooting distance division information, and image height division information are described.

  The correction value storage area b holds a correction value corresponding to a combination of division points of each optical parameter stored in the division point information storage area a3. For example, in the region of z [0] −f [0] [0] −d [0] [0], when the focal length is the division point z [0] on the Wide side and the shooting distance is the focal length z [0] mm. Correction values of the full image heights h [0] to h [hNum] of d [0] [0] of the open Fno when the shortest shooting distance f [0] [0] and the aperture is the focal length z [0] mm Is described. In this way, the optical correction information of the entire lens unit area is described in the correction value storage area b.

  The above description has been made on the assumption that the optical correction data is transferred from the lens unit. However, there are various types of lens units in the interchangeable lens type imaging device, and some types of lens units do not hold the auxiliary optical data in the in-lens unit storage unit 101c depending on characteristics such as the manufacturing time and the cost of the lens unit. Regarding such a lens, optical correction data may be stored in advance in the storage unit 108 in the camera main body 100, or the user may obtain it from the outside using a personal computer (hereinafter, PC) or the like. In such a case, data can be stored in advance, so there is no need to worry about communication time, so even if all lens units are unified to a size with sufficient margin without changing the data size for each lens good. Of course, there may be a system in which a lens unit that holds data in the in-lens unit storage unit 101c and a lens unit that does not hold data coexist.

  Returning to FIG. 1, a method of applying the optical correction data obtained as described above will be described.

  The optical correction unit 111 generates a correction value corresponding to the photographing condition acquired by the state detection unit 107 from the optical correction data stored in the storage unit 108, and uses the correction value to correct image deterioration due to optical characteristics. Details of this correction processing will be described later.

  The calculated correction value is recorded in association with the image file. As a result, it is possible to confirm later with what correction value the generated image file is corrected. For example, when the created image file is read later by an application such as a PC, it is possible to determine whether the image file has been optically corrected by referring to these pieces of information. Therefore, it is possible to prevent double correction.

  Further, in a mode for recording RAW data that has not been post-processed, by adding the optical correction result information to a file, the image data (RAW data) is not changed as originally intended, but the same as an application. Optical correction is possible. FIG. 5 exemplifies the data structure of a file in which the optical correction result is recorded. In areas 501 to 503 shown in FIG. 5, whether or not peripheral light amount correction, lateral chromatic aberration correction, and distortion aberration correction are performed is recorded. Record the correction result. When a flag indicating that no correction is made (for example, 0) is recorded, for example, when the peripheral light amount correction is set to “do not” (when the area 501 is 0), all of the peripheral light amount correction result area 505 is 0. Record invalid values such as. On the other hand, when the peripheral light amount correction is applied (when the area 501 is 1), the calculated correction value is recorded in the area 505. The correction data to be recorded is acquired by recording correction data corresponding to the shooting conditions from the optical correction data shown in FIG.

  Here, since the image height division number hNum may be different for each lens unit, it is recorded in the image height division number area 504. For the correction result thus obtained, peripheral light amount correction values Vig [0] to Vig [hNmu] that are paired with the image heights h [0] to h [hNum] are recorded in the peripheral light amount correction result area 505. Here, Vig [0] to Vig [hNmu] record values indicating how much the light amount is reduced at the corresponding image height. In this example, a common number of divisions is used for all corrections. However, correction data may be created so that the number of image height divisions can be varied for each correction. In that case, of course, it is necessary to record the number of image height divisions for each correction.

  Similarly, the presence / absence and result of magnification chromatic aberration correction are recorded in areas 502 and 506, and the presence / absence and result of distortion aberration correction are recorded in areas 503 and 507. The lateral chromatic aberration correction value AberR indicates the amount of R color shift with respect to G at each image height, and AberB indicates the amount of B color shift with respect to G at each image height. The correction value Dist for correcting distortion aberration holds a value indicating how much the distortion is distorted with respect to the ideal state. The correction result area is generally recorded in the maker note area added to the image file, but this is not restrictive.

  The image processed by the image processing unit 104 is stored in the image recording medium 109 in a predetermined format. Further, the display unit 105 may display an image that has been subjected to a predetermined display process on the image after the optical correction process, or an image that is not subjected to the optical correction process.

  A series of control is performed by the system controller 110, and mechanical driving of the lens unit is performed by the lens unit control unit 106 according to an instruction from the system controller 110.

  <Optical Correction Value Calculation Processing> Next, the optical correction value calculation processing of this embodiment will be described with reference to FIG. In the following, although optical correction is used, peripheral light amount correction, lateral chromatic aberration correction, distortion aberration correction, and other corrections can be handled in the same manner. 3 is realized by the system controller 110 expanding and executing the control program stored in the storage unit 108 in a work area of a memory such as a RAM.

  When the system controller 110 captures an image, the system controller 110 acquires a capturing condition when the capturing is performed (S301). The photographing conditions referred to here correspond to the lens ID, focal length, photographing distance, aperture value, etc. of the lens unit 101 at the time of photographing, which are conditions necessary for optical correction.

  In S302, the system controller 110 determines whether or not the lens unit 101 at the time of shooting is a lens capable of communicating optical correction data. In this determination method, a flag indicating that the lens unit 101 side can communicate optical correction data may be transmitted to the camera body side, or may be determined from the lens ID or the like on the camera body side. If the optical correction data can be communicated in S302, the process proceeds to S303, and the system controller 110 determines whether or not the optical correction data acquired from the lens unit 101 is correct. The reason for determining the validity of such data is that, as described above, communication between the lens unit and the camera body may be unstable compared to normal wired communication, and may not be performed correctly. This is because there is a high possibility that the previous data remains due to communication. That is, when such incomplete communication is performed, if the correction is applied without performing the determination of S303, an unexpected correction result may be obtained, or the image may be destroyed in the worst case. This is because there is a possibility that correction will be made.

  Here, an example of the determination process of the correctness of the correction data in S303 will be described with reference to FIG.

  In FIG. 4, in S401, the system controller 110 compares the lens ID acquired in S301 with the lens ID described in the header area a in the optical correction data. If the lens IDs do not match, the system controller 110 determines that the correct correction data is not recorded, and determines as False (S405). On the other hand, if both lens IDs match, the system controller 110 performs focal length determination (S402). Here, the system controller 110 determines whether or not the focal length data of the imaging condition acquired in S301 is a value existing in the correction data. Specifically, referring to the focal length division information in the division point information storage area (a-3) in FIG. 2, the focal length acquired in S301 is a value between z [0] and z [zNum-1]. Determine whether or not. Here, if the photographing focal length is not included between z [0] and z [zNum−1], it is determined that the photographing condition and the correction data are not correlated, and it is determined as False (S405). On the other hand, when the correlation is obtained, it is determined as True (S406).

  Similarly, in S403 and S404, if the correlation between the aperture value of the photographing condition acquired in S301 and the value existing in the correction data is obtained for the photographing distance, True (S406), the system controller 110 cannot obtain the correlation. In the case, it is determined as False (S405).

  Returning to the description of FIG. 3, when the determination result in S <b> 303 is False, the system controller 110 sets a correction non-application flag (for example, 0) in areas 501 to 503 indicating whether correction is performed for each correction in FIG. 5. (S304). On the other hand, if the determination result in S303 is True, the system controller 110 reads the image height division number point hNum from the division point number storage area a1 in FIG. 2 for file recording (S305), and the image in FIG. Recording is performed in the high division number area 504 (S306).

  Thereafter, the system controller 110 calculates a correction value suitable for the shooting condition from the correction data of FIG. 2 using the focal length, the shooting distance, and the aperture value, which are the shooting conditions read in S301 (S307). Here, when there is no corresponding data, the nearest value may be calculated by interpolation. The correction values calculated in this way are recorded in the areas 505 to 507 according to the types of correction as illustrated in FIG. 5 (S308). Finally, since the correction value is normally created, a value (for example, 1) indicating the correction application corresponding to each correction type is recorded in the areas 501 to 503 (S309).

  On the other hand, if the result of determination in S302 is that the lens unit cannot communicate optical correction data, the system controller 110 uses the lens ID acquired in S301 in the storage unit 108 in which optical correction data is recorded in advance. Whether there is optical correction data corresponding to the lens is searched (S310). As a result, if correction data exists, the system controller 110 calculates a correction value and records the correction result in the same manner as in S307 to S309. On the other hand, if there is no correction data, the system controller 110 cannot perform correction, and records a correction non-application flag as in S304 (S311).

  As described above, the optical correction of the lens unit after replacement can be appropriately performed regardless of whether or not the optical correction data can be acquired from the lens unit after replacement. Further, by recording the correction result in a file, it is possible to appropriately perform image processing in an application or the like described later.

  [Embodiment 2] As Embodiment 2, an example in which image processing is performed by an application such as a PC using a file in which correction results are recorded will be described.

  FIG. 7 shows an example of a screen displayed when an application is activated on a PC or the like.

  In FIG. 7, reference numeral 701 denotes an image display area on the application, which displays an image in a folder selected by the user. Reference numeral 702 denotes an optical correction application selection area, and the user can set for each correction process whether or not to apply optical correction to the displayed image. Specifically, checking the horizontal check box labeled “Apply” means that the corresponding optical correction has been applied. In addition, for an image selected by the user, an image processed under the conditions set by pressing the OK button 703 after the processing on the application is completed can be newly recorded.

  In particular, a RAW image in which the output signal of the image sensor 102 is recorded without passing through the image processing unit 104 is converted into a general image file (JPEG or BMP) by post-processing by the user with a PC or the like after shooting. The When this RAW image is processed by an application, it is desirable to display the image that is first displayed before the user edits the image after converting it to the setting at the time of shooting of the camera body. In other words, when the setting is such that optical correction is applied when a RAW image is captured, it is expected that the optical correction is applied to an image to be displayed first. However, since the RAW image is data before image processing, it is necessary to apply optical correction when displaying the image on the application side.

  Here, with reference to FIG. 6, the image display process in the application of the captured image according to the second embodiment will be described.

  In FIG. 6, first, when the user selects a RAW image to be edited from the image display area 701 on the application (S601), the application refers to the correction result recording area shown in FIG. 5 of the selected image (S602). .

  Next, the application reads the regions 501 to 503 indicating the presence / absence of each correction and determines the setting state at the time of shooting in order to determine whether or not the RAW image has been shot with a setting to which optical correction is applied (S603). . If the image is shot with a setting where optical correction is not applied, the optical correction processing (S604 to S606) is skipped and other image processing is performed (S607). The other image processing here means a series of development processing such as pixel interpolation processing, luminance signal processing, and color signal processing as described above.

  On the other hand, when the image was shot with the setting to which the optical correction is applied, the application first reads the image height division number information 504 (S604), and then, according to the read image height division number information 504, each application The correction result areas 505 to 507 are read (S605). Here, if the image height division number is variable for each lens unit, there arises a problem that the corresponding correction value cannot be read correctly unless this image height division information is recorded.

  Next, the application performs correction processing by converting the read correction value into a format suitable for the correction of the application (S606). Thereafter, other image processing is performed (S607), and an image is displayed (S608).

  As described above, even when the optical correction data cannot be acquired from the lens unit, it is possible to apply correction equivalent to the processing in the camera on the application. In addition, when an image to which correction is applied is selected, the user can visually recognize whether the correction is appropriate by automatically checking and displaying the check box of the optical correction application selection area 702 for each correction.

  In the above-described example, the optical correction is not executed on the application unless the setting for applying the optical correction at the time of image shooting is performed, but there may be a case where the user wants to apply the optical correction after shooting. Therefore, even when the image is shot with settings that do not apply optical correction, information on the image height division number area 504 and the correction result areas 505 to 507 is recorded in a file. By doing so, it becomes possible for the user to apply optical correction by checking a check box in the optical correction application selection area 702 after shooting.

The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of this embodiment is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads out and executes the program. It is processing to do.

Claims (11)

An interchangeable lens imaging device,
Acquisition means for acquiring correction data from the mounted lens unit;
Correction means referring to the acquired correction data, and correction means for correcting a signal caused by optical characteristics of a lens at the time of shooting of an image shot under a predetermined shooting condition;
An image pickup apparatus comprising: a recording unit that records information associated with correction data acquired by the acquisition unit in association with an image. The correction data is for each lens unit, and includes information corresponding to at least one parameter of focal length, aperture value, shooting distance, and image height for each lens unit;
The imaging apparatus according to claim 1, wherein the number of division points obtained by discretely dividing each parameter at the time of shooting and a correction value for each division point of the parameters are recorded in a file. The correction means performs any correction process of light quantity correction, chromatic aberration correction, distortion aberration correction,
The imaging apparatus according to claim 1, wherein the recording unit records presence / absence of application of the correction process and a correction result.   4. The apparatus according to claim 1, further comprising a determination unit that determines the validity of the correction data by comparing information corresponding to a parameter at the time of shooting and information corresponding to the correction data. The imaging apparatus of Claim 1. A selection means for selecting a photographed image;
Acquisition means for acquiring correction data used for correcting a signal caused by optical characteristics of a lens at the time of photographing the selected image;
Setting means for setting whether or not to apply correction at the time of shooting the selected image;
A correction unit that corrects an image with reference to the acquired correction data when the correction is set to be applied;
An image processing apparatus comprising: display means for displaying an image corrected by the correction means. A control method for an interchangeable lens imaging device,
An acquisition step of acquiring correction data from the mounted lens unit;
A correction step that refers to the acquired correction data and corrects a signal caused by optical characteristics of a lens at the time of shooting of an image shot under a predetermined shooting condition;
And a recording step of recording the information corresponding to the acquired correction data and the image in association with each other. A selection process for selecting a photographed image;
An acquisition step of acquiring correction data used for correction of a signal caused by optical characteristics of the lens at the time of photographing the selected image;
A setting step for setting whether to apply correction at the time of shooting the selected image;
A correction step of correcting an image with reference to the acquired correction data when it is set to apply the correction;
And a display step for displaying the corrected image.   A non-transitory computer-readable storage medium storing a program for causing a computer to execute the control method for an imaging apparatus according to claim 6.   A program for causing a computer to execute the image processing method according to claim 7.   A computer-readable storage medium storing a program for causing a computer to execute the control method for an imaging apparatus according to claim 6.   A computer-readable storage medium storing a program for causing a computer to execute the image processing method according to claim 7.

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