Patent Publication Number: US-9413943-B2

Title: Information registration system, information registration method, registration apparatus, and image pickup apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of application Ser. No. 13/402,376, filed Feb. 22, 2012; which is a continuation of application Ser. No. 12/511,409, filed Jul. 29, 2009, now U.S. Pat. No. 8,248,509, the entire disclosures of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an information registration system for registering correction information of a removable lens apparatus in an image pickup apparatus, as well as an information registration method, a registration apparatus, and an image pickup apparatus. 
     2. Description of the Related Art 
     In recent years, in some image pickup apparatuses such as digital still cameras to/from which a lens apparatus can be attached/removed, it has been possible to store correction information for lens apparatuses in a memory, read correction information corresponding to the attached lens apparatus from the memory, and correct a picked-up image. With such image pickup apparatuses, it is necessary to pre-store, in the memory, correction information for lens apparatuses that are to be attached and used. 
     Image pickup apparatuses themselves have become diverse, and particularly with entry models, there are cases in which the memory capacity and processing capability are not very high due to price reduction. It is therefore possible for part of the correction information to not be used (i.e., some correction processing is not executed). 
     Japanese Patent Laid-Open No. 2006-267770 discloses technology relating to an image pickup apparatus that obtains, from a lens apparatus attached to the image pickup apparatus, unique information that identifies the lens apparatus, obtains optical characteristics information for the lens that corresponds to the obtained unique information via a computer network, and stores the optical characteristics information in a memory. 
     However, in the above conventional technology, the lens information that is stored in a memory of the image pickup apparatus has been automatically selected based on the unique information of the lens apparatus that is attached to the image pickup apparatus. Therefore, a user has not been able to visually confirm which lens apparatus&#39;s correction information, from a list of lens apparatuses that can be registered in the image pickup apparatus from a registration apparatus, will be stored in the memory of the image pickup apparatus. 
     Also, in the above conventional technology, even if the image pickup apparatus does not use part of the correction information, all of the correction information is stored in the memory of the image pickup apparatus. It is therefore possible for memory space to be wasted by unnecessary correction information that is not actually used. 
     SUMMARY OF THE INVENTION 
     The present invention has been achieved in light of the above situation. A characteristic feature of the present invention is that, in the case of registering correction information of a lens apparatus in an image pickup apparatus, a user can visually confirm which lens apparatus&#39;s correction information, from a list of lens apparatuses that can be registered in the image pickup apparatus from a registration apparatus, is to be registered. Another characteristic feature of the present invention is preventing unnecessary correction information that is not used by the image pickup apparatus from being stored in the memory of the image pickup apparatus. 
     According to an aspect of the present invention, there is provided an information registration system including an image pickup apparatus to/from which a lens apparatus having identification information set therein can be attached/removed, and a registration apparatus for registering correction information of a lens apparatus in the image pickup apparatus by connecting to and communicating with the image pickup apparatus, the registration apparatus comprising: a lens information storage unit that stores lens information so as to be able to be referenced by identification information, the lens information including information that identifies the model of a lens apparatus and correction information that corresponds thereto; an obtaining unit that obtains, from the image pickup apparatus, identification information that is set in a lens apparatus that is attached to the image pickup apparatus; a display unit that displays a confirmation window that displays a list of models of lens apparatuses whose lens information is stored in the lens information storage unit, such that the model of the lens apparatus corresponding to the identification information obtained by the obtaining unit can be distinguished from the model of another lens apparatus; an operation unit that receives, from a user via the confirmation window, a designation of the model of a lens apparatus whose correction information is to be registered in the image pickup apparatus; and a transmission unit that transmits, from the lens information storage unit to the image pickup apparatus, registration information that includes identification information and correction information of the lens apparatus whose designation was received by the operation unit, and the image pickup apparatus comprising: a correction information storage unit that stores correction information of a lens apparatus; a reply unit that transmits the identification information set in the attached lens apparatus to the registration apparatus in accordance with a request from the registration apparatus; a receiving unit that receives the registration information transmitted from the registration apparatus; and an update unit that updates storage content of the correction information storage unit based on the registration information received by the receiving unit. 
     According to an aspect of the present invention, there is provided an information registration method performed by (i) an image pickup apparatus to/from which a lens apparatus having identification information set therein can be attached/removed, and that has a correction information storage unit that stores correction information of a lens apparatus, and (ii) a registration apparatus for registering correction information of a lens apparatus in the image pickup apparatus by connecting to and communicating with the image pickup apparatus, the registration apparatus having an operation unit, a display unit, and a lens information storage unit that stores lens information so as to be able to be referenced by identification information, the lens information including information that identifies the model of a lens apparatus and correction information that corresponds thereto, the information registration method comprising: an obtaining step of obtaining, from the image pickup apparatus by the registration apparatus, identification information that is set in a lens apparatus that is attached to the image pickup apparatus; a displaying step of displaying, on the display unit, a confirmation window that displays a list of models of lens apparatuses whose lens information is stored in the lens information storage unit, such that the model of the lens apparatus corresponding to the identification information obtained in the obtaining step can be distinguished from the model of another lens apparatus; an operating step of receiving, from a user by the operation unit via the confirmation window, a designation of the model of a lens apparatus whose correction information is to be registered in the image pickup apparatus; a transmitting step of transmitting by the registration apparatus, from the lens information storage unit to the image pickup apparatus, registration information that includes identification information and correction information of the lens apparatus whose designation was received in the operating step; a receiving step of receiving, by the image pickup apparatus, the registration information transmitted from the registration apparatus; and an updating step of updating, by the image pickup apparatus, storage content of the correction information storage unit based on the registration information received in the receiving step. 
     According to an aspect of the present invention, there is provided a registration apparatus for registering correction information of a lens apparatus in an image pickup apparatus to/from which a lens apparatus having identification information set therein can be attached/removed, by connecting to and communicating with the image pickup apparatus, the registration apparatus comprising: a lens information storage unit that stores lens information so as to be able to be referenced by identification information, the lens information including information that identifies the model of a lens apparatus and correction information that corresponds thereto; an obtaining unit that obtains, from the image pickup apparatus, identification information that is set in a lens apparatus that is attached to the image pickup apparatus; a display unit that displays a confirmation window that displays a list of models of lens apparatuses whose lens information is stored in the lens information storage unit, such that the model of the lens apparatus corresponding to the identification information obtained by the obtaining unit can be distinguished from the model of another lens apparatus; an operation unit that receives, from a user via the confirmation window, a designation of the model of a lens apparatus whose correction information is to be registered in the image pickup apparatus; and a transmission unit that transmits, from the lens information storage unit to the image pickup apparatus, registration information that includes identification information and correction information of the lens apparatus whose designation was received by the operation unit. 
     According to an aspect of the present invention, there is provided an image pickup apparatus to/from which a lens apparatus having identification information set therein can be attached/removed, and that communicably connects to a registration apparatus for registering correction information of a lens apparatus, the image pickup apparatus comprising: a correction information storage unit that stores correction information of a lens apparatus; a reply unit that transmits identification information set in an attached lens apparatus to the registration apparatus in accordance with a request from the registration apparatus; a receiving unit that receives registration information that has been transmitted from the registration apparatus and that includes the correction information and the identification information; and an update unit that updates storage content of the correction information storage unit based on the registration information received by the receiving unit. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing a configuration of an image pickup apparatus according to a first embodiment of the present invention. 
         FIG. 2  is a conceptual diagram showing an array of an image pickup device. 
         FIG. 3  is a conceptual diagram showing an overview of a lens information registration system. 
         FIG. 4  is a conceptual diagram showing an exemplary configuration of recorded content on a recording medium on which optical characteristics correction data is recorded. 
         FIG. 5  is a block diagram showing a configuration of a registration apparatus. 
         FIG. 6  is a ladder chart showing operations performed by the image pickup apparatus and the registration apparatus. 
         FIG. 7  is a conceptual diagram showing an exemplary user interface (UI) window. 
         FIG. 8  is a conceptual diagram showing an exemplary UI window. 
         FIG. 9  is a flowchart showing a flow of processing in the registration apparatus. 
         FIG. 10  is a conceptual diagram showing an exemplary configuration of recorded content in a central control unit in an image pickup apparatus according to a second embodiment. 
         FIG. 11  is a conceptual diagram showing an exemplary configuration of a correction data reference table. 
         FIG. 12  is a flowchart showing a flow of processing in a registration apparatus according to the second embodiment. 
         FIG. 13  is a diagram showing an exemplary configuration of optical characteristics correction data stored in the image pickup apparatus that can only perform peripheral light quantity correction. 
         FIG. 14  is a flowchart showing processing performed in step S 711  of  FIG. 9 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the present invention are described below with reference to the drawings, but the present invention is not limited to the embodiments below. Also, these embodiments of the present invention are merely preferred embodiments of the present invention, and do not limit the scope of the present invention. 
     First Embodiment 
       FIG. 1  is a block diagram showing a configuration of an image pickup apparatus  301  according to a first embodiment of the present invention. Note that the image pickup apparatus  301  described below is a so-called digital still camera (hereinafter, called a digital camera). 
     The image pickup apparatus  301  includes an image pickup unit  10 , a data processing unit  20 , an output image memory  30 , a data interface unit  31 , an image display unit  32 , a user interface unit  33 , and a central control unit  34 . The image pickup unit  10  has a lens apparatus  11  and an image pickup device  12 . The data processing unit  20  has an AGC/AD conversion unit  21 , an image data conversion unit  22 , an image degradation correction processing unit  23 , an image processing unit  24 , and a compression processing unit  25 . 
     To describe the above configuration in more detail, the central control unit  34  has a CPU (Central Processing Unit)  34   a  and an internal memory  34   b . The CPU  34   a  has the functions of performing overall management of the image pickup apparatus  301  and issuing processing instructions. In  FIG. 1 , broken-line arrows indicate the flow of processing, and solid-line arrows indicate the flow of image data. 
     The image pickup unit  10  is unit in which the lens apparatus  11  projects an image of an object onto the light receiving face of the image pickup device  12 , thus picking up the image of the object. Specifically, when the shutter (not shown) of the image pickup apparatus  301  has been pressed, or when the image display unit  32  is used as a viewfinder, the image pickup unit  10  picks up an image of the object as described above in accordance with an instruction from the CPU  34   a.    
     The lens apparatus  11  has an image pickup optical system  11   a  for forming an image of an object, and a memory  11   b  that has set therein unique identification information that enables identifying the type of the lens apparatus  11  and the lens apparatus  11  itself. The lens apparatus  11  has mechanisms for zooming, determining the focus position, and driving the aperture (not shown) in the image pickup optical system  11   a , and has the functions of detecting the values of the zoom state, the focus position, and the aperture diameter during shooting via the CPU  34   a . Also, the identification information stored in the memory  11   b  can be read by the central control unit  34  via a connection point (not shown) that electrically connects the lens apparatus  11  and the image pickup apparatus  301 . Also, the lens apparatus  11  can be attached to and removed from the image pickup apparatus  301 , and different lens apparatuses  11  can be attached to and removed from the image pickup apparatus  301 . As a correction information storage means, the internal memory  34   b  stores optical characteristics correction data (correction information) such as the limb darkening and distortion aberration of the lens apparatus  11 , and the magnification chromatic aberration and axial chromatic aberration. 
     The image pickup device  12  is a single photoelectric conversion device that converts an optical signal obtained from an image formed on the light receiving face into an electrical signal for each light receiving pixel that corresponds in position. The image pickup device  12  also has a function for performing color separation with use of R (red), G (green), and B (blue) filters that are arranged in the Bayer pattern shown in  FIG. 2  in the pixels of a light receiving unit of the image pickup device  12 . The exposure time and object image obtaining timing of the image pickup device during shooting is controlled by the CPU  34   a , and image data obtained as an electrical signal is transferred to the data processing unit  20  in accordance with an instruction from the CPU  34   a.    
     Upon being transferred to the data processing unit  20 , the image signal is first transferred to the AGC/AD conversion unit  21 . The AGC/AD conversion unit  21  performs AGC (Automatic Gain Control) to amplify and correct the intensity of the received image signal, performs AD conversion to convert the image signal into digital data, and transfers the digital data to the image data conversion unit  22 . The image data conversion unit  22  then converts the received digital data into digital image (tone) data. 
     The digital image data resulting from the conversion performed by the image data conversion unit  22  is transferred to the image processing unit  24  after the image degradation correction processing unit  23  has performed image correction processing thereon, or without correction processing being performed. This branch in the processing occurs due to the existence of conditions such as whether or not the camera is set to perform correction, and whether or not correction data exists for the optical system used during shooting. 
     The image degradation correction processing unit  23  corrects image degradation in the picked-up image that has been picked up by the lens apparatus  11 . In accordance with an instruction from the CPU  34   a , and based on the optical characteristics correction data for the lens apparatus  11  that is stored in the internal memory  34   b , the image degradation correction processing unit  23  corrects image degradation in the received image data that occurs due to the above-described optical characteristics of the lens apparatus  11 . Specifically, a limb darkening characteristic, a magnification chromatic aberration characteristic, an axial chromatic aberration characteristic, a distortion aberration characteristic, and the like are corrected in accordance with the optical characteristics correction data. In this case, the data used in the image degradation correction processing performed by the image degradation correction processing unit  23  may be any data that is useful for correction, such as a lens design value, lens aberration data, and a lens aberration correction parameter. 
     Meanwhile, the image processing unit  24  performs image conversion processing based on data regarding color systems, such as color system conversion processing and luminance/color separation. Generally, such image conversion processing is performed based on the assumption that for an arbitrary pixel position, the object image formation position matches between the color systems. There are various methods of correcting the optical characteristics, and correction may be performed by any means. 
     The image data on which image degradation correction has been performed is transferred to the image processing unit  24 , which performs various types of image processing such as luminance color separation processing, white balance adjustment, gray balance adjustment, density adjustment, color balance adjustment, and edge emphasizing. 
     The image data resulting from the image processing performed by the image processing unit  24  is transferred to the compression processing unit  25 , which compresses the image data using a predetermined image compression processing method. The compression method may be any method of compressing image data, such as JPEG (Joint Photographic Expert Group), TIFF (Tag Image File Format), and JPEG2000. The compressed image data is transferred to the output image memory  30  as output image data, and stored therein. 
     The output image memory  30  that stores the output image data is a recording medium that can be mounted in and removed from the image pickup apparatus  301 , and an output image can be directly transferred to another information terminal device via the recording medium. Also, the output image memory  30  is a re-writable memory, examples of which include a compact flash (registered trademark) memory, and card-shaped memories such as a smart media card, a memory stick, a PC card, or an ATA card. The output image memory  30  may be, for example, a general-purpose memory such as an MO disk, a floppy (registered trademark) disk, a ZIP disk, a CD-R, a CD-RW, or a DVD-ROM, and may take any form. 
     The data interface unit  31  is an interface for connecting to another information terminal device wirelessly or by wire so as to enable communication therebetween. Specifically, under the control of the central control unit  34 , the data interface unit  31  performs data communication via USB communication, a LAN, the Internet, or the like. For example, the data interface unit  31  can transfer image data stored in the output image memory  30  to another information terminal device via wired transmission or wireless transmission. 
     The image display unit  32  is configured from a liquid crystal display or the like, and can display image data recorded in the output image memory  30 , camera shooting settings, and the like. As an electronic viewfinder, the image display unit  32  can also display object images. The image display function of the image display unit  32  can be switched ON and OFF via the user interface unit  33 , and display information can also be switched via the user interface unit  33 . 
     The following describes operations of the registration apparatus according to the first embodiment as well as shows coordination with the image pickup apparatus described above.  FIG. 3  is a conceptual diagram showing an overview of a lens information registration system  1 . As shown in  FIG. 3 , in the lens information registration system  1 , the image pickup apparatus  301  indicates a digital camera that has the optical correction functions described above, and it is assumed that different lens apparatuses  11  can be attached and removed. 
     The registration apparatus  302  is an information device such as a so-called personal computer, and it is assumed that an application program that can communicate with the image pickup apparatus  301  is installed therein. It is also assumed that the registration apparatus  302  has registered therein correction values of the optical characteristics correction data described above for various types of lens apparatuses. 
     Since the registration apparatus  302  generally has a sufficient recording capacity, it is assumed that all correction values for lens apparatuses  11  that the image pickup apparatus  301  is compatible with are recorded therein. The means for recording the optical characteristics correction data described above in the registration apparatus  302  may be, for example, connecting to the Internet and downloading the data, or directly recording the data from an external recording medium to the personal computer. 
     In order to obtain the optical characteristics correction data, the image pickup apparatus  301  can, for example record necessary data from among the optical characteristics correction data recorded in the registration apparatus  302 , from the data interface unit  31  shown in  FIG. 1  to the central control unit  34  also shown in  FIG. 1  via a USB cable  303 . 
       FIG. 4  is a diagram showing an exemplary configuration of recorded content on a recording medium on which optical characteristics correction data is recorded. It is sufficient for the structure in which the optical characteristics correction data is recorded in the central control unit  34  of the image pickup apparatus  301  to be the same as the structure in which the optical characteristics correction data is recorded in the registration apparatus  302 . The data configuration of the recording medium is mainly divided into an area  801  for an overall optical characteristics correction table, and lens data areas  802  and  803  for respective lenses, and a lens data area is provided for each lens for which correction is performed. 
     The information recorded in optical correction table header information  804  in the area  801  can be, for example, the number of lenses that are accommodated by the optical correction table, the data amount of correction data for each lens, and the data amount of each optical correction data piece. 
     Header information  805  of each lens data piece has recorded therein, for example, model identifying information that is unique to each lens apparatus (e.g., a lens ID (identification information) or lens name), as well as the Tele end and Wide end focal length, shortest shooting distance, and an open aperture value of the corresponding lens, such that this information can be referenced. Such information is used to identify the lens apparatus, and is used as parameters when performing correction calculations. By referencing the lens ID in the header information  805  and reading data that matches the lens ID read from the lens apparatus, it is possible to read optical characteristics correction data that corresponds to the lens apparatus. In other words, the information that identifies the model of the lens apparatus (e.g., a lens name) and lens information including corresponding correction information is stored on the recording medium such that referencing by the lens ID is possible. 
     The lens data area for each lens has recorded therein correction values for the corresponding optical correction. For example, recorded as peripheral light quantity correction data  806  is data indicating the degree of a drop in light quantity at various distances from the optical axis center for each zoom position, focus position, and aperture position. Also, recorded as distortion aberration correction data  807  is data indicating the degree of actual distortion with respect to the ideal image height at various distances from the optical axis center for each zoom position, focus position, and aperture position. Recorded as magnification chromatic aberration correction data  808  are correction values such as the degree to which an image formation position of the R or B component is shifted with respect to the G component at various distances from the optical axis center for each zoom position, focus position, and aperture position. The optical characteristics to be corrected and the data content are of course not limited to the above description. 
     The following describes an exemplary configuration of the optical characteristics correction data stored in the internal memory  34   b  of the image pickup apparatus  301  with reference to  FIG. 13 . In the example shown in  FIG. 13 , it is assumed that the image pickup apparatus  301  can perform only peripheral light quantity correction as image degradation correction processing. If the image pickup apparatus  301  performs only peripheral light quantity correction, it is not necessary to store optical correction data (i.e., the distortion aberration correction data  807  and the magnification chromatic aberration correction data  808  shown in  FIG. 4 ) other than peripheral light quantity correction data. The data structure shown in  FIG. 13  therefore has an area  1301  for an overall optical characteristics correction table, and areas  1302  and  1303  for respective lens apparatuses that can be attached to the image pickup apparatus  301 . 
     Similarly to the area  801  shown in  FIG. 4 , the area  1301  has stored therein optical correction table header information  1304  relating to lens apparatuses registered in the image pickup apparatus  301  (the registration of lens apparatuses is described later). 
     Similarly to the header information  805  shown in  FIG. 4 , the areas  1302  and  1303  for respective lens apparatuses have stored therein information (header information  1305 ) relating to lens apparatuses registered in the image pickup apparatus  301 . The areas  1302  and  1303  for respective lens apparatuses have further stored therein peripheral light quantity correction data  1306  for each lens apparatus registered in the image pickup apparatus  301 . 
     Although  FIG. 13  shows only the areas  1302  and  1303  for the two lenses apparatuses A and B respectively, in actuality, respective areas are provided for all lens apparatuses that are registered in the image pickup apparatus  301 . 
     Of course, if the image pickup apparatus  301  can perform distortion aberration correction and magnification chromatic aberration correction in addition to peripheral light quantity correction, it is sufficient for the data structure shown in  FIG. 13  to be the same as the data structure shown in  FIG. 4 . 
     The following describes the configuration of the registration apparatus  302  with reference to  FIG. 5 . As shown in  FIG. 5 , the registration apparatus  302  includes a control unit  401 , a RAM (Random Access Memory)  402 , a storage unit  403 , a display unit  404 , an operation unit  405 , and an I/F unit  406 . 
     The control unit  401  is configured from a CPU and the like, and centrally controls the operations of units in the registration apparatus  302 . Specifically, the control unit  401  controls the operations of the units by expanding program data  403   a  stored in the storage unit  403  to the RAM  402 , and sequentially executing the program data  403   a.    
     As a lens information storage means, the storage unit  403  is a ROM (Read Only Memory), an HDD (Hard Disk Drive), or the like, and stores the program data  403   a  and optical characteristics correction data  403   b . Also, a recording medium  407  can be mounted to and removed from the storage unit  403  by a connector (not shown), and the storage unit  403  can, for example, read data stored on the recording medium  407  and write data to the recording medium  407 . For example, the program data  403   a , the optical characteristics correction data  403   b , and the like may be read from the recording medium  407  and stored in the storage unit  403 . The program data  403   a  is, for example, the application program described above, and the optical characteristics correction data  403   b  is the above-described optical characteristics correction data that has been read from the recording medium and stored in the storage unit  403 . 
     The display unit  404  is a display apparatus such as an LCD (Liquid Crystal Display), and displays windows under the control of the control unit  401 . Specifically, the display unit  404  displays UI-related windows that are described later. The operation unit  405  is a keyboard, pointing device, or the like, and receives operation input from a user and outputs the operation input to the control unit  401 . Specifically, the operation unit  405  receives operation instructions from the user via the UI, such as a registration instruction originating from the designation of the model of a lens apparatus whose correction information is to be registered. 
     The I/F unit  406  is an interface that, under the control of the control unit  401 , connects to an external device wirelessly or by wire so as to enable communication with the external device. Specifically, the I/F unit  406  connects to and performs USB communication with the image pickup apparatus  301  via the USB cable  303 . The I/F unit  406  also connects to and performs data communication with an external device  306  via a communication network  305  such as the Internet or a LAN (Local Area Network) in accordance with a predetermined communication protocol. An example of data communication with the external device  306  via the communication network  305  is downloading the optical characteristics correction data described above via the Internet. 
     The following describes operations performed by the image pickup apparatus  301  and the registration apparatus  302  in the lens information registration system  1  with reference to  FIGS. 6, 7, 8, 9, and 14 .  FIG. 6  is a ladder chart showing operations performed by the image pickup apparatus  301  and the registration apparatus  302 .  FIGS. 7 and 8  show exemplary UI windows displayed by the display unit  404  according to the application program described above, and  FIG. 9  is a flowchart showing a flow of processing in the registration apparatus  302 .  FIG. 14  is a flowchart showing processing performed in step S 711  of  FIG. 9 . 
     As shown in  FIG. 6 , in the registration apparatus  302 , when a communication connection with the image pickup apparatus  301  has been confirmed, under the control of the control unit  401 , the application program is started and a UI is displayed by the display unit  404 . The UI displayed by the display unit  404  when the application program is started is a UI related to selections in a main menu, and this UI has areas  501 ,  502 , and  503  as shown in  FIG. 7 . 
     The area  501  displays settings of the connected image pickup apparatus  301  that cannot be modified using the application. Specific examples of these settings include the drive mode (single shot, continuous shooting), the shooting mode (manual, aperture priority, shutter priority, etc.), the remaining battery life, and the remaining number of photographs that can be shot. The area  502  displays settings of the image pickup apparatus  301  that can be changed using the application. Specific examples of these settings include the white balance mode, the ISO sensitivity, the recording image quality, and the photometric mode. A shooting system menu is displayed in the area  503 , and mainly image-related settings can be performed. For example, it is possible to select a mode for outputting colors and a brightness specialized for a specific object (e.g., “landscape mode” or “portrait mode”), and it is possible to set WB correction for finely adjusting the white balance set in the area  502 . The optical characteristics correction data of the present invention can also be registered in the area  503 . Note that the arrangement in this UI window is not limited to the above description. 
     The following describes processing in the case of registering a desired lens apparatus&#39;s optical characteristics correction data in the registration apparatus  302  that is in the possession of a user, with reference to mainly  FIGS. 6, 8, 9, and 14 . As shown in  FIG. 9 , upon the user clicking the “optical correction” button in the area  503 , the control unit  401  of the registration apparatus  302  starts processing for registering optical characteristics correction data in the image pickup apparatus  301  (S 701 ). 
     After the processing has started in step S 701 , the control unit  401  performs a communication check with the image pickup apparatus  301  (S 702 ). In the check performed in step S 702 , the registration apparatus  302  requests the connected image pickup apparatus  301  to transmit the identification information of the lens apparatus  11  that is currently attached and the optical characteristics correction data that is pre-registered in the central control unit  34  of the image pickup apparatus  301  (S 401 ). Upon receiving the request, the image pickup apparatus  301  transmits the identification information of the lens apparatus that is currently attached (e.g., the name and lens ID) and the optical characteristics correction data that is registered in the central control unit  34  to the registration apparatus  302  (S 402 ). 
     As a result of the processing in step S 401  and step S 402 , the registration apparatus  302  obtains the identification information of the lens apparatus  11  that is attached to the image pickup apparatus  301  and is to be registered. In step S 402 , the entire structure shown in  FIG. 13  may be transmitted as the information, or only the identification information of registered lens apparatuses may be extracted and transmitted as the information. In other words, in step S 402 , the identification information of registered lens apparatuses whose optical characteristics correction data is pre-stored in the central control unit  34  is transmitted as a reply. 
     When the communication check described above has ended, the control unit  401  obtains the information transmitted from the image pickup apparatus  301  as a reply (S 703 ), and prepares to cause the display unit  404  to, before the transmission of the data to be registered, display a UI used when performing lens registration. The window displayed by the display unit  404  as the UI is a confirmation window for confirming data content before the transmission of data to be registered, and as shown in  FIG. 8 , this window has an area  601 , an area  602 , an area  603 , a button  604 , and an OK button  605 . 
     The area  602  displays a list of, for example, the names (models) of lens apparatuses that are recorded in the registration apparatus  302  and for which optical correction can be performed. The display of this list is performed by the control unit  401  reading the optical characteristics correction data  403   b  stored in the storage unit  403 . Also, the control unit  401  adds a check to the checkbox in front of each lens name displayed in the area  602  that corresponds to a lens apparatus whose optical characteristics correction data obtained in step S 402  is already registered (S 704 ). In other words, the area  602  displays a list of lens apparatuses that are recorded in the registration apparatus  302 , as well as lens apparatuses whose correction information is stored and registered in the image pickup apparatus  301  such that they can be distinguished from other lens apparatuses based on the existence of checks. Accordingly, it is possible in the area  602  to explicitly inform the user of lens apparatuses whose optical characteristics correction data is already registered in the image pickup apparatus  301 . 
     Meanwhile, based on the identification information obtained in step S 402 , the control unit  401  determines whether the optical characteristics correction data recorded in the registration apparatus  302  includes optical characteristics correction data related to the attached lens apparatus (S 705 ). In other words, in step S 705 , the control unit  401  determines whether the optical characteristics correction data related to the lens apparatus that is currently attached to the image pickup apparatus  301  is recorded in the registration apparatus  302 . 
     If the control unit  401  determines in step S 705  that the optical characteristics correction data is recorded, based on the registered optical characteristics correction data that was obtained in step S 402 , the control unit  401  determines whether the total number of models of registered lens apparatuses is not more than the number of models that can be registered in the image pickup apparatus  301  (S 706 ). More specifically, the control unit  401  compares a total of the number of registered lens apparatuses and the number of lens apparatuses to be registered, against a predetermined setting in the memory or the like indicating the number of lens apparatuses that can be registered, and determines whether the former is not more than the latter. 
     If the control unit  401  has determined in step S 706  that the number of registered lens apparatuses is less than the number of lens apparatuses that can be registered, the control unit  401  adds a check to the checkbox of the name of the attached lens apparatus that is displayed in the area  602  as described above (S 707 ). In other words, as a result of step S 707 , the registration apparatus  302  displays the attached lens apparatus and other lens apparatuses so as to be distinguishable from each other based on checks in checkboxes. Here, if the optical characteristics correction data of the attached lens apparatuses is not recorded in the registration apparatus  302 , or if the number of registered lens apparatuses is greater than or equal to the number of lens apparatuses that can be registered, the control unit  401  displays a warning display on the display unit  404  using a popup window or the like (S 706   a ). By this warning display, the registration apparatus  302  can notify the user that no more lens apparatuses can be registered in the image pickup apparatus  301 , or that the optical characteristics correction data of the attached lens apparatus does not exist. 
     When the processing described above has been completed, the control unit  401  displays the UI shown in  FIG. 8  on the display unit  404  (S 708 ). This enables the user to find out at a glance which lens apparatuses are registered in the image pickup apparatus  301 , and which lens apparatuses have not been registered. Here, the means for notifying the user is not limited to the checkboxes described above as an example. Note that if merely checks are added to checkboxes, it is impossible to distinguish between the lens apparatus that was attached and already-registered lens apparatuses in the display. Therefore, when adding a check to the checkbox for the attached lens apparatus, the display may be made explicit by displaying, for example, “Attached lens A has been added” in the area  603  or the like. Rather than being limited to the area  603 , the displaying means can be a method of, for example, changing the color of the characters in the corresponding lens name displayed in the area  602 . 
     If the currently attached lens apparatus  11  is exchanged while the UI shown in  FIG. 8  is being displayed by the display unit  404 , under the control of the central control unit  34  that is an exchange notifying means, the image pickup apparatus  301  transmits the identification information of the lens apparatus that is newly attached after the exchange to the registration apparatus  302  (S 403 ). Upon obtaining such identification information, the control unit  401  of the registration apparatus  302  determines whether the optical characteristics correction data of the newly attached lens apparatus is recorded in the registration apparatus  302 . If the optical characteristics correction data is already recorded, the control unit  401  adds a check to the checkbox for the name of the newly attached lens apparatus in the area  602 , and updates the display of the UI. If the optical characteristics correction data is not recorded, the control unit  401  may display a warning display on the display unit  404 . 
     When updating the display of this UI, it is preferable to not uncheck the checkbox for the lens apparatus that was attached before the exchange. By not unchecking this checkbox, the number of checks is increased as lens apparatuses are exchanged one after another. Accordingly, a user who possesses multiple lens apparatuses can efficiently register the optical characteristics correction data of the lens apparatuses in the image pickup apparatus  301  by merely exchanging the lens apparatus attached to the image pickup apparatus  301 . 
     The control unit  401  also receives an additional user selection of checkboxes for the lens apparatuses displayed in the area  602  via the operation unit  405  that is a mouse or the like, and adds checks in accordance with the selection instruction (S 709 ). In this case, the user selects a desired lens from the lens name list in the area  602 . For example, the user selects, from the lens name list, a lens apparatus name (model) that is different from the lens apparatus attached to the image pickup apparatus  301 . 
     In general, dozens of removable lenses can be attached to a lens-replaceable image pickup apparatus, and some image pickup apparatuses are compatible with over a hundred lenses. The user must find a desired lens from among these, and making the selection from a list of all lenses is very difficult. For this reason, the area  601  includes category-specific selection buttons such as “ultra wide-angle/wide-angle”, “normal/medium telephoto”, “telephoto”, “macro”, “zoom”, and “APS-C sensor lens”. In accordance with the user operation instruction received via the selection buttons arranged in the area  601 , the control unit  401  displays only the lens apparatuses in the selected category in the area  602 . This enables the user to efficiently find a desired lens when making a selection from the lens name list. 
     Also, upon receiving a user instruction via the button  604 , the control unit  401  displays only the lens apparatuses that have checks in the area  602 . This enables the user to see at a glance a list of lens apparatuses to be registered. Also, the area  603  displays the maximum number of lens apparatuses that can be registered in the image pickup apparatus  301  and the number of lenses that are currently registered in the image pickup apparatus  301 , thereby showing how many more lens apparatuses can be registered. 
     When a check is added to the checkbox of a lens apparatus in step S 709 , if a correction function related to the checked lens apparatus is restricted, the control unit  401  may display a warning display on the display unit  404  when the checkbox is checked. In other words, a warning display is displayed if, in step S 709 , the correction information included in the checked lens information that is to be registered satisfies a warning condition pre-set in the memory, such as a correction function being restricted. 
     One example of a warning condition for which a warning display is to be displayed is the case in which the lens apparatus that has been checked does not have range information. In general, most lens apparatuses transmit information such as focal length information and an aperture value to the image pickup apparatus through communication with the image pickup apparatus. However, there are many lens apparatuses that do not transmit, to the image pickup apparatus, range information that does not readily vary according to the optical system. In the case of such a lens apparatus, it is highly possible for correction to not be appropriately applied, compared to other lens apparatuses that transmit range information. It is completely impossible to determine whether a lens apparatus transmits range information based on the lens name etc. Accordingly, by warning the user to this effect when such a lens apparatus is checked, the user can use the correction function in the image pickup apparatus after being made aware of the risk that correction will not be appropriately applied. 
     Another example of a case in which a warning display is to be displayed is the case of a lens apparatus that has an optical characteristic for which correction cannot be performed, and in this case, a warning display to that effect is displayed. For example, if distortion aberration correction is to be performed with a lens apparatus such as a fish-eye lens, a very large amount of correction will need to be performed. Performing such correction in the case of this lens is a burden on the system and the correction is difficult, and there are cases in which the image pickup apparatus  301  cannot accommodate the correction. However, peripheral light quantity correction, magnification aberration correction, and the like can be performed similarly to other lens apparatuses. When such a lens apparatus exists and the lens apparatus is checked, the user may be notified by displaying a warning display on the display unit  404  to the effect that distortion aberration correction cannot be performed. 
     It is sufficient for information indicating whether the lens apparatus has the range information described above, and information indicating whether the lens apparatus is a lens apparatus for which distortion aberration correction can be performed to be recorded in the header information  805  of the optical characteristics correction table shown in  FIG. 4 . When a check has been added, by referencing the optical characteristics correction data  403   b , the control unit  401  can determine whether to display the warning displays described above, and display a warning display on the display unit  404  when necessary. 
     The user clicks the OK button  605  upon completing the selection, and thus the control unit  401  determines whether a data registration instruction has been received from the user according to whether the OK button  605  has been operated (S 710 ). Here, the application changes the format of the optical correction data so as to be compatible with the model of the image pickup apparatus  301  in which the optical correction data is to be registered (S 711 ). 
     The following describes this processing with reference to  FIG. 14 . First, when the OK button  605  has been clicked (S 1401 ), based on information relating to the image pickup apparatus  301  that has been obtained beforehand, the application determines the model of the image pickup apparatus  301  that is connected to the registration apparatus  302  (S 1402 ). The following describes an example in which there are three image pickup apparatus models, namely Type 1 , Type 2 , and Type 3 . 
     Type 1  is a model that can only perform correction A (e.g., peripheral light quantity correction). Type 2  is a model that can only perform correction A and correction B (e.g., peripheral light quantity correction and distortion aberration correction). Type 3  is a model that can perform correction A, correction B, and correction C (peripheral light quantity correction, distortion aberration correction, and magnification chromatic aberration correction). 
     The following describes the case in which the image pickup apparatus  301  connected to the registration apparatus  302  has been determined to be Type 1 . In this case, the application performs the following processing. Among the optical characteristics correction data stored in the registration apparatus  302  ( FIG. 4 ), the application extracts only optical characteristics correction data necessary for Type 1  (peripheral light quantity correction data) from the optical characteristics correction data of the lens apparatus to be registered this time (S 1403 ). The application then converts the extracted optical characteristics correction data into a format for storage in the Type 1  image pickup apparatus. An example of the configuration of the optical characteristics correction data after format conversion is shown in  FIG. 13 . Note that the processing of step S 1404  and step S 1405  is performed in the cases of Type 2  and Type 3  image pickup apparatuses respectively. 
     When format conversion has ended, the application transmits the converted optical characteristics correction data to the image pickup apparatus  301  (S 1406 , S 712 , S 404 ). 
     Then, in the image pickup apparatus  301 , the optical characteristics correction data is recorded to the internal memory  34   b  based on the registration information transmitted from the registration apparatus  302  (storage content updating), and thereafter the central control unit  34  transmits a registration completion notification to the registration apparatus  302  (S 405 ). In the registration apparatus  302 , when the registration completion notification has been received, the above-described processing performed by the control unit  401  is ended (S 713 ). This series of processing enables the user to efficiently register the optical characteristics correction data of a desired lens apparatus in the image pickup apparatus  301  that is in the user&#39;s possession. 
     Second Embodiment 
     The following describes a second embodiment of the present invention in which the structure of the recorded optical characteristics correction data in the central control unit  34  of the image pickup apparatus  301  is different from the structure of the recorded optical characteristics correction data in the storage unit  403  in the registration apparatus  302 . Note that a description of the image pickup apparatus  301  and the registration apparatus  302  according to the second embodiment has been omitted since they are the same as in the first embodiment. 
     In the first embodiment, the optical characteristics correction data is described as being recorded using the same structure in the image pickup apparatus  301  and the registration apparatus  302 , as shown in  FIGS. 4 and 13 . However, the following problem occurs when the recording structure is the same. Note that although part of the correction data (specifically distortion aberration correction data and magnification aberration correction data) is missing in  FIG. 13 , the structures in  FIG. 13  and  FIG. 4  would be the same if this part were included, and therefore the correction data shown in  FIG. 13  and  FIG. 4  is treated as having “the same” structure. 
     If the optical characteristics correction table is managed according to lens IDs, the user performs registration by making a determination based on the names of lens apparatuses, as shown in the area  602  of  FIG. 8 . There is no problem if the lens IDs and names completely correspond one-to-one, but in reality there are cases in which multiple lens IDs are assigned to lenses that have the same name and optical system. 
     This occurs in a situation such as, for example, when the firmware in a lens apparatus is changed during lens production, and there is a need to distinguish between old-firmware and new-firmware lens apparatuses that have the same name, different lens IDs are assigned to the lens apparatuses. Such lens apparatuses have different lens IDs even though the name and optical system is the same. If the recording structure for correction data for such lens apparatuses is the same between the image pickup apparatus  301  and the registration apparatus  302  as described in the first embodiment, the user would of course not be able to know which lens apparatus names have multiple lens IDs. Accordingly, there is the problem that when the user selects a certain lens apparatus, there may be a sudden increase in the number of registered lenses shown in the area  603 , which creates a situation that is difficult for the user to understand. Also, even if the maximum number of lenses that can be registered has been determined, it is not actually possible to register the maximum number of lenses. 
     The second embodiment describes a method for addressing this problem with reference to  FIGS. 10, 11, and 12 .  FIG. 10  is a conceptual diagram showing an exemplary configuration of recorded content in the central control unit  34  of the image pickup apparatus  301  according to the second embodiment.  FIG. 10  is different from  FIG. 4  described above with respect to the addition of a correction data reference table  904  between an area  901  and a lens data area  902 . 
     As shown in  FIG. 11 , the correction data reference table  904  is roughly divided into two areas. One area includes areas  1001  to  1003  in which lens IDs are recorded. The other area includes areas  1004  to  1006  in which offset Data 1  to offset Data 3 , which respectively correspond to the lens IDs in the areas  1001  to  1003 , are recorded. The offset data is a value indicating an offset amount from the address at which the optical characteristics correction data of the corresponding lens ID is recorded, that is to say, the offset data is reference destination information for referencing correction information by identification information. Accordingly, by appropriately setting the offset data, the correction data reference table  904  enables the same correction information to be referenced by different identification information. The number of combinations of lens IDs and offset data is set higher than the maximum number of lenses that can be registered. 
     The following describes a flow of operations performed by the registration apparatus  302  when optical characteristics correction data is registered from the registration apparatus  302  to the image pickup apparatus  301  using this recording method, with reference to  FIG. 12 . First, when the user has selected optical characteristics correction data to be written to the image pickup apparatus  301  using the same method as in the first embodiment, the OK button  605  shown in  FIG. 8  is operated. Accordingly, as shown in  FIG. 12 , upon detecting that the OK button  605  has been clicked, the control unit  401  starts performing processing according to the second embodiment (S 1101 ). 
     When processing has started, the control unit  401  internally performs the following processing before transmitting optical characteristics correction data to the image pickup apparatus  301 . First, the control unit  401  obtains all lens names that are checked (S 1102 ). If none of the lenses are checked in step S 1102 , the control unit  401  transmits a table including blank optical characteristics correction data to the image pickup apparatus  301  (corresponds to step S 404  in  FIG. 4 ). 
     If checked lenses exist in step S 1102 , the control unit  401  references the optical characteristics correction data  403   b , and seeks one-by-one for optical characteristics correction data relating to the checked lens apparatuses. Specifically, the control unit  401  first determines whether the first checked lens apparatus has multiple lens IDs (S 1103 ). Specifically, in step S 1103 , the control unit  401  determines whether the optical characteristics correction data  403   b  includes optical characteristics correction data pieces that are for the same lens apparatus name as the lens apparatus to be registered, but are referenced by different lens IDs. 
     If the first checked lens apparatus does not have multiple lens IDs, the control unit  401  records the corresponding lens ID in the first area (area  1001 ) among the areas shown in  FIG. 11 . The control unit  401  also records an offset value from the location of the optical characteristics correction data for the lens ID in the area (area  1004 ) corresponding to the first area (S 1105 ). 
     The following describes a case in which the first lens apparatus has multiple lens IDs. Assume the case in which one lens name has two lens IDs. The control unit  401  records one of the two lens IDs in the first area (area  1001 ) among the areas shown in  FIG. 11 , and records an offset value from the location of the optical characteristics correction data in the area (area  1004 ) corresponding to the first area. Furthermore, the control unit  401  records the other lens ID in the area  1002 , and records the same offset value from the location of the optical characteristics correction data (i.e., the same value as in the area  1004 ) in the area  1005  (S 1104 ). In other words, in step S 1104 , the control unit  401  records reference destination information for referencing the same optical characteristics correction data by different lens IDs. Accordingly, for lens apparatuses whose names (models) are the same but have different identification information, only one of the recorded registration information pieces for these lens apparatuses includes correction information. The other registration information pieces that are recorded for these lens apparatus include reference destination information for referencing the one registration information piece instead of including correction information. 
     According to the processing described above, if there are lens apparatuses that have different lens IDs but have the same optical system, and the difference between the lens IDs exists simply to distinguish between an old-firmware lens apparatus and a new-firmware lens apparatus, the same optical characteristics correction data can be shared between the different lens IDs. In this way, adding the correction data reference table  904  to the optical characteristics correction data eliminates the need to have redundant correction information related to multiple lens IDs. Furthermore, since redundant correction information is not recorded even if there are multiple lens IDs due to differences in firmware, situations in which the maximum number of lenses cannot actually be recorded are eliminated, and the user does not particularly need to be concerned about the above-described problem related to the maximum number of lenses that can be recorded. 
     The control unit  401  repeats the operations described above for all of the lenses apparatuses that are to be registered (S 1106 ). After step S 1106 , the control unit  401  records the optical characteristics correction data that is to be registered using the data structure described with reference to  FIG. 10 , and transmits the optical characteristics correction data to the image pickup apparatus  301  (specifically, this processing is similar to the processing of step S 404 , and differs only with respect to the optical characteristics correction data that is transmitted). At this time, the control unit  401  references the registered optical characteristics correction data obtained from the image pickup apparatus  301  in step S 401  and step S 402 , and checks whether there are any redundancies with the optical characteristics correction data that is to be registered. If a redundancy is found in this check, the control unit  401  may transmit, to the image pickup apparatus  301 , only reference destination information for referencing the redundant optical characteristics correction data by the different lens IDs. In other words, the control unit  401  may transmit only reference destination information for optical characteristics correction data that is already registered in the image pickup apparatus  301 . Doing this enables optical characteristics correction data that is already registered in the image pickup apparatus  301  to also be referenced by different lens IDs. Note that a description of processing other than the processing described above has been omitted due to being the same as in the first embodiment. 
     Note that the description in the above embodiments is merely exemplary, and the present invention is not limited thereto. Appropriate changes can be made to the configurations and operations in the embodiments described above. 
     Other Embodiments 
     Aspects of the present invention can also be realized by a computer of a system or apparatus (or devices such as a CPU or MPU) that reads out and executes a program recorded on a memory device to perform the functions of the above-described embodiment(s), and by a method, the steps of which are performed by a computer of a system or apparatus by, for example, reading out and executing a program recorded on a memory device to perform the functions of the above-described embodiment(s). For this purpose, the program is provided to the computer for example via a network or from a recording medium of various types serving as the memory device (e.g., computer-readable medium). 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2008-200079, filed on Aug. 1, 2008, and 2008-235734, filed on Sep. 12, 2008, which are hereby incorporated by reference herein in their entirety.