Abstract:
An imaging device includes measures to prevent it from becoming unusable due to battery discharge or no storage in the storage medium. The device includes a battery charge function and a data transfer function. After detecting the charge amount remaining in the battery and the remaining storage capacity in the storage medium, the order of priority for performing battery charge and data transfer is set. The imaging device is switched between the battery charge function and the data transfer function based on the set priority order. The battery charge is executed in accordance with the detected remaining charge and the data transfer in accordance with the detected remaining storage capacity.

Description:
[0001]    This application is a continuation of U.S. patent application Ser. No. 11/862,581, filed Sep. 27, 2007, the entire content of which is herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an imaging device for use in a digital camera having a battery charging function and a data transfer function, and to a control method therefor, and program for the imaging device. 
         [0004]    2. Description of the Related Art 
         [0005]    In recent years, the number of products which make use of the DLNA (Digital Living Network Alliance) standard for connecting electronic products and every-day electronic appliances to one another over a network has been increasing. Moreover, it is predicted that electronic apparatus in the home will become increasingly networked. Connection via a network allows the electronic apparatus to transfer data. For example, moving picture data captured by a digital video camera can be easily transferred to a hard disk recorder by simply connecting the digital video camera to the network. 
         [0006]    Also, the storage capacity of storage media used in electronic apparatus is increasing extremely quickly. As a result, it is now possible to record high quality images and moving pictures onto storage media for long periods. When a storage medium is capable of repeatedly recording moving picture data or image data in this way, the captured image data must be periodically transferred to an external device. However, when the amount of data is large, the data transfer takes time. 
         [0007]    Also, if the electronic apparatus is a portable digital camera, charge is also necessary since most cameras are battery driven. Generally, when the battery is being charged, portable cameras are constrained by the inability to perform other operations because built-in power supply circuits stop supplying power to power consuming units other than the charging circuit. 
         [0008]    To solve the above-described problem, a technique by which current supplied from a data transfer bus is used to simultaneously charge the battery and transfer data has been proposed (see, for instance, Japanese Laid-Open Patent Publication (Kokai) No. 2002-237971). 
         [0009]    However, in conventional cameras, battery charge and data transfer after use take a long time to complete. Hence the problem exists that the camera cannot be used for long periods while the battery charge and data transfer are taking place. 
         [0010]    Also, when there is only a limited amount of time before the camera is to be reused, it may be the case that only one of the battery charge and the data transfer is possible. This means that the camera may have insufficient storage space or run out of battery when next used. 
         [0011]    Moreover, it is the user who has to switch a camera operation unit between the batter charge and the data transfer. Hence, the user is obliged to monitor the amount of charge remaining in the battery and the available storage capacity in the storage medium. This is complicated and time consuming. 
         [0012]    Hence, a way of automatically charging the battery and performing data transfer as appropriate in the limited period of time before the camera is next used is needed for when the battery charge and data transfer cannot be fully completed. 
         [0013]    According to the above-described Japanese Laid-Open Patent Publication (Kokai) No. 2002-237971, the battery charge and data transfer can be performed simultaneously, and it is therefore possible to shorten the total period required for battery charge and data transfer. However, since the method of the Japanese Laid-Open Patent Publication (Kokai) No. 2002-237971 cannot be realized without a connection unit that includes a power supply function such as the USB (Universal Serial Bus) of a personal computer, connection using the method for connecting the electronic apparatus to the network is not necessarily possible. Also, since the construction of the power circuit is complex, an increase in the number of parts and a rise in cost are unavoidable. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention provides an imaging device, and a control method therefor, and a program capable of preventing the imaging device from becoming unusable due to the battery running out or a lack of storage capacity in the storage medium, by performing battery charge and data transfer in a limited period of time. 
         [0015]    To attain the above object, in a first aspect of the present invention, there is provided an imaging device including a battery charge function for charging a battery and a data transfer function for transferring data recorded in a storage medium to an external apparatus, comprising: a remaining charge detecting unit configured to detect an amount of charge remaining in the battery; a remaining storage capacity detecting unit configured to detect a remaining storage capacity available for recording data in the storage medium; a setting unit configured to set an order of priority for performing battery charge and data transfer; and a control unit configured to switch a function of the imaging device between the battery charge and the data transfer based on the order of priority set by the setting unit, execute the battery charge in accordance with a detection result of the remaining charge detecting unit and execute the data transfer in accordance with a detection result of the remaining storage capacity detecting unit. 
         [0016]    The amount of charge remaining detected by the remaining charge detecting unit can be less than a prescribed value, the control unit can prioritize battery charge without reference to the order of priority set by the setting unit, and can perform battery charge until the amount of charge remaining reaches at least the prescribed value. 
         [0017]    The remaining storage capacity detected by the remaining storage capacity detecting unit can be less than a prescribed value, the control unit prioritizes data transfer without reference to the order of priority set by the setting unit, and performs data transfer until the remaining storage capacity reaches at least the prescribed value. 
         [0018]    When a connection with the external apparatus is not established or the external apparatus is unable to receive transfer data, the control unit can perform battery charge without reference to the order of priority set by the setting unit. 
         [0019]    When charge of the battery is not possible or the battery is not fitted to the imaging device, the control unit can perform data transfer charge without reference to the order of priority set by the setting unit. 
         [0020]    To attain the above object, in a second aspect of the present invention, there is provided an imaging device having a battery charge function for charging a battery and a data transfer function for transferring data recorded on a storage medium to an external apparatus, comprising: a remaining charge detecting unit configured to detect an amount of charge remaining in the battery; and a control unit configured to, when the amount of charge remaining detected by the remaining charge detecting unit has not reached a first prescribed value, execute battery charge until the amount of charge remaining in the battery reaches a second prescribed value, subsequently execute data transfer, and then perform battery charge until the amount of charge remaining in the battery reaches a third prescribed value. 
         [0021]    According to the present invention, switching between battery charge and data transfer is executed based on the order of priority to allow battery charge and data transfer in a limited period of time without extra work for the user, an increase in the number of parts, or a rise in cost. It is therefore possible to solve the problems of the imaging device becoming unusable due to the battery running out and insufficient remaining storage capacity on the storage medium. 
         [0022]    To attain the above object, in a third aspect of the present invention, there is provided a control method for an imaging device having a battery charge function for charging a battery and a data transfer function for transferring data recorded on a storage medium to an external apparatus, comprising: a remaining charge detecting step of detecting an amount of charge remaining in the battery; a remaining storage capacity detecting step of detecting a remaining storage capacity available for recording data in the storage medium; a setting step of setting an order of priority for performing the battery charge and the data transfer; and a control step of switching between the battery charge and the data transfer based on the order of priority set in the setting step, executing the battery charge in accordance with a detection result of the remaining charge detecting step, and executing the data transfer in accordance with a detection result of the remaining storage capacity detecting step. 
         [0023]    To attain the above object, in a fourth aspect of the present invention, there is provided a control method for an imaging device having a battery charge function for charging a battery and a data transfer function for transferring data stored in a storage medium to an external apparatus, comprising: a remaining charge detecting step of detecting an amount of charge remaining in the battery; and a control step of, when the amount of charge remaining detected in the remaining charge detecting step has not reached a first prescribed value, executing battery charge until the amount of charge remaining in the battery reaches a second prescribed value, subsequently executing data transfer, and then performing battery charge until the amount of charge remaining in the battery reaches a third prescribed value. 
         [0024]    In order to solve the above-described problems, according to a fifth aspect of the present invention, there is provided a program for causing a computer to execute the control method for the imaging device. 
         [0025]    According to the present invention, switching between battery charge and data transfer is executed based on the order of priority to allow battery charge and data transfer in a limited period of time without extra work for the user, an increase in the number of parts, or a rise in cost. It is therefore possible solve the problems of the imaging device becoming unusable due to the battery running out or the remaining storage capacity on the storage medium being insufficient. 
         [0026]    The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  is a block diagram showing a construction of a digital video camera as an imaging device of a first embodiment of the present invention. 
           [0028]      FIG. 2A  to  FIG. 2D  show various setting screens of the digital video camera in  FIG. 1 ;  FIG. 2A  and  FIG. 2B  are directed to menu selection screens;  FIG. 2C  is directed to a charging/transfer setting screen; and  FIG. 2D  is directed to a prescribed remaining charge/prescribed remaining storage capacity screen. 
           [0029]      FIG. 3  is a flowchart showing a procedure for camera internal operation control processing when the digital video camera has been set to charge prioritizing mode. 
           [0030]      FIG. 4A  and  FIG. 4B  show setting screens of the digital video camera;  FIG. 4A  is directed to a currently charging screen;  FIG. 4B  is directed to a currently transferring screen. 
           [0031]      FIG. 5  is a flowchart showing the procedure for camera internal operation control processing when a digital video camera, as an imaging device of a second embodiment of the present invention, has been set to data transfer prioritizing mode. 
           [0032]      FIG. 6A  and  FIG. 6B  are flowcharts showing the procedure for camera internal operation control processing when a digital video camera, as an imaging device of a third embodiment of the present invention, has been set to charge prioritizing mode. 
           [0033]      FIG. 7A  to  FIG. 7E  show examples of error display by the digital video camera when performing the camera internal operation processing shown in  FIG. 6A  and  FIG. 6B ;  FIG. 7A  and  FIG. 7B  are directed to examples of error display indicating that battery charge is not possible;  FIG. 7C  to  FIG. 7E  are directed to examples of error display indicating that data transfer is not possible. 
           [0034]      FIG. 8A  and  FIG. 8B  are flowcharts showing the procedure for camera internal operation control processing when a digital video camera, as an imaging device of a fourth embodiment of the present invention, has been set to data transfer prioritizing mode. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]    The present invention will now be described in detail with reference to the drawings showing preferred embodiments thereof. 
         [0036]    It should be noted that the relative arrangement of the components, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. 
         [0037]      FIG. 1  is a block diagram showing a construction of a digital video camera as an imaging device of a first embodiment of the present invention. 
         [0038]    In  FIG. 1 , a digital video camera  100  includes a microcomputer  101 , an optical unit  102 , an imaging element  103 , a storage medium  106 , a storage medium remaining capacity detecting unit  109 , a data transfer I/F  111 , a battery  113 , and a remaining charge detecting unit  118 . The digital video camera  100  has a charge prioritizing mode in which charging the battery  113  is prioritized and a data transfer prioritizing mode in which transfer of image data to an external apparatus  112  is prioritized. 
         [0039]    The microcomputer  101  is capable of controlling the digital video camera  100 , and executes processing shown in the below-described flowcharts based on a program. The optical unit  102  includes a lens, an aperture, and a motor for driving the lens and aperture, receives external light (subject light), and forms an image on an imaging surface of the imaging element  103 . The imaging element  103  converts the external light to an electronic signal. The signal resulting from the conversion by the imaging element  103  is supplied to an image processing unit  105  via a data storage unit  104 , and becomes digital image data. The digital image data is temporarily stored in the data storage unit  104 . 
         [0040]    A storage medium controlling unit  107  controls reading and writing of the image data to and from the storage medium  106 . The reading and writing of the image data to and from the storage medium  106  is performed via a storage medium access I/F  108 . The storage medium remaining capacity detecting unit  109  detects a remaining storage capacity available for recording image data (hereinafter remaining storage capacity) in the storage medium  106 . The image data stored in the storage medium  106  is stored in the data storage unit  104  via the storage medium access I/F  108 . 
         [0041]    The image data stored in the data storage unit  104  is converted by the image processing unit  105  into image data capable of being displayed by a moving image display unit  110 . The moving image display unit  110  displays the image data (moving image data) based on control by the microcomputer  101 . Also, the image data stored in the storage medium  106  can be transferred to the external apparatus  112  via the data transfer I/F  111 . 
         [0042]    A charge controlling unit  114  charges the battery  113  using a charging circuit  115 . An AC power adaptor  116  connects the digital video camera  100  to an AC power source (not shown in the drawings). Current from the AC power source is supplied to a power source circuit  117  via the AC power adaptor  116 . The power source circuit  117  supplies electrical power to the various units of the digital video camera  100 . The remaining charge detecting unit  118  detects an amount of charge remaining in the battery  113 . An operation unit  119  is used to select instructions for imaging, recording, playback and the like, and to select the charge prioritizing mode/transfer prioritizing mode, and, besides various operation buttons, includes a display unit for displaying various settings screens ( FIG. 2A  to  FIG. 2D ,  FIG. 4A  to  FIG. 4B ,  FIG. 7A  to  FIG. 7E ). 
         [0043]    Settings and a setting method for the charge prioritizing mode/data transfer prioritizing mode in the digital video camera  100  of the present embodiment with the above-described construction is described below with reference to  FIG. 2A  to  FIG. 2D . 
         [0044]    The charge prioritizing mode is a mode for prioritizing the charge of the battery  113  over the data transfer (see  FIG. 3 ). When the user selects the charge prioritizing mode using the operation unit  119 , the microcomputer  101  begins charge prioritizing mode processing. At this point, the microcomputer  101  begins charging the battery  113  using the charging circuit  115 , and continues charging until a user-indicated prescribed remaining charge (a prescribed value for the amount of charge remaining) is reached. 
         [0045]    The microcomputer  101  then performs data transfer to the external apparatus  112  via the data transfer I/F  111  until a user-indicated prescribed remaining storage capacity (a prescribed value for the amount of remaining storage capacity), which is to say the available storage space in the storage medium  106 , is reached. On completion of the data transfer, the amount of charge remaining in the battery  113  and the remaining storage capacity in the storage medium  106  have reached the corresponding prescribed values. In any left over time, the microcomputer  101  charges the battery  113  until fully charged and transfers all remaining data to the storage medium  106 . 
         [0046]    The data transfer prioritizing mode, on the other hand, is a mode for prioritizing the data transfer to the external apparatus  112  over the charge of the battery  113  (see  FIG. 5 ). Thus, in the data transfer prioritizing mode processing, the order of priority for the data transfer processing and the charge processing is the reverse of that in the above-described charge prioritizing mode. 
         [0047]      FIG. 2A  to  FIG. 2D  show various setting screens of the digital video camera in  FIG. 1 ;  FIG. 2A  and  FIG. 2B  are directed to menu selection screens;  FIG. 2C  is directed to a charging/transfer setting screen; and  FIG. 2D  is directed to a prescribed remaining charge/prescribed remaining storage capacity screen. 
         [0048]    A setting method for the charge prioritizing mode/data transfer prioritizing mode is described in  FIG. 2A  to  FIG. 2D . Initially, when the user performs a predetermined operation on the operation unit  119 , the microcomputer  101  displays a menu selection screen  201  on the moving image display unit  110 . Items on the menu selection screen  201  include “movie settings”, “stills settings”, “display settings”, “system settings”, “time settings” and “return”. When the user selects “system settings” from the menu selection screen  201 , the microcomputer  101  switches from the menu selection screen  201  to a “system settings” menu selection screen  202 . Items on the “system settings” menu selection screen  202  include “remote control settings”, “operation sound settings”, “power management settings”, “charge/transfer settings”, and “return”. 
         [0049]    When the user selects “charge/transfer settings” from the “system settings” menu selection screen  202 , the microcomputer  101  switches from the menu selection screen  202  to a charge/transfer setting screen  203 . Items on the charge/transfer setting screen  203  include “charge prioritizing mode”, “transfer prioritizing mode”, and “cancel prioritizing mode”. When the user selects “charge prioritizing mode” or “transfer prioritizing mode” from the charge/transfer setting screen  203 , the microcomputer  101  switches to a prescribed remaining charge/prescribed remaining storage capacity setting screen  204 . Items on the prescribed remaining charge/prescribed remaining storage capacity setting screen  204  include “prescribed remaining charge” and “prescribed remaining storage capacity”. 
         [0050]    When the user selects “charge prioritizing mode” or “transfer prioritizing mode” from the charge/transfer setting screen  203 , it is possible to set the “prescribed remaining charge” or the “prescribed remaining storage capacity” separately via the prescribed remaining charge/prescribed remaining storage capacity setting screen  204 . The setting of the prescribed remaining amount is substantially the same for both the charge prioritizing mode and the transfer prioritizing mode. 
         [0051]    When desiring neither the “charge prioritizing mode” nor the “transfer prioritizing mode”, the user can select the “cancel prioritizing mode” from the charge/transfer setting screen  203 . In this case, the charge of the battery  113  is performed when the digital video camera  100  is connected to the AC power source via the AC power adaptor  116 . Moreover, the data transfer to the external apparatus  112  is performed when the user causes data transfer to begin via an operation (a predetermined operation on the operation unit  119 ). 
         [0052]    Thus, in the digital video camera  100 , it is possible to set the order of priority for the order in which the battery charge and the data transfer is to be performed. Also, in the digital video camera  100 , charge of battery  113  to reach the prescribed remaining charge and data transfer from the storage medium  106  to reach a prescribed remaining storage capacity can be performed within a fixed period. 
         [0053]    In the present embodiment, the camera internal operation control processing when the digital video camera  100  has been set to the charge prioritizing mode is described with reference to the flow chart of  FIG. 3 . 
         [0054]      FIG. 3  is a flowchart showing the procedure for camera internal operation control processing when the digital video camera  100  has been set to the charge prioritizing mode. 
         [0055]    As shown in  FIG. 3 , at the beginning of processing in the charge prioritizing mode set by the user via the operation unit  119 , the microcomputer  101  of the digital video camera  100  checks the amount of charge remaining in the battery  113  using the remaining charge detecting unit  118 . Next, the microcomputer  101  calculates the amount of charge remaining in the battery  113  based on a detection result from the remaining charge detecting unit  118 , and judges whether the amount of charge remaining is at least the prescribed value (step S 301 ). Here, is it is assumed that the prescribed remaining charge for the battery  113  is 50% of the fully charged level. 
         [0056]    When the amount of charge remaining in the battery  113  is less than 50% of the fully charged level, the microcomputer  101  charges the battery  113  using the charging circuit  115 , and continues charging in a succession of fixed periods until the charge level reaches 50% of the fully charged level (step S 302 ). When a judgment result in step S 301  indicates that the amount of charge remaining in the battery  113  exceeds 50% of the fully charged level or has reached at least 50% of the fully charged level as a result of charging, the microcomputer  101  judges that the amount of charge remaining is sufficient, and proceeds to step S 303 . 
         [0057]    Next, to perform data transfer, the microcomputer  101  detects the remaining storage capacity of the storage medium  106  using the storage medium remaining capacity detecting unit  109 . The microcomputer  101  calculates the remaining storage capacity in the storage medium  106  based on a detection result from the storage medium remaining capacity detecting unit  109 , and judges whether the remaining storage capacity of the storage medium  106  is at least the prescribed value (step S 303 ). Here, it is assumed that the prescribed value for the remaining storage capacity of the storage medium  106  has been set to 50% of the total capacity of the storage medium  106 . 
         [0058]    When the judgment result of step S 303  indicates that the remaining storage capacity of the storage medium  106  is less than 50% of the total capacity, the microcomputer  101  begins transferring data to the external apparatus  112  connected to the digital video camera  100  via the data transfer I/F  111  (step S 304 ). Data transfer is performed file by file, with one file being the smallest data unit. When, the remaining storage capacity of the storage medium  106  exceeds 50% of the total capacity, or has exceeded 50% of the total capacity as a result of the data transfer, the microcomputer  101  proceeds to step S 305 . 
         [0059]    For an affirmative judgment in the above-described step S 303 , the remaining charge in the battery  113  has to exceed 50% of the fully charged level, and the remaining storage capacity of the storage medium  106  has to exceed 50% of the total capacity. The microcomputer  101  judges whether the amount of charge remaining in the battery  113  is the fully charged level (step S 305 ). When the amount of charge remaining is less than the fully charged level, the microcomputer  101  charges the battery  113  using the charging circuit  115  (step S 306 ), and then proceeds directly to step S 307  when the amount of charge remaining reaches the fully charged level. 
         [0060]    Next, the microcomputer  101  judges whether non-transferred data is present in the storage unit  106  (step S 307 ). When non-transferred data is absent, the microcomputer  101  ends the processing. When non-transferred data is present, the microcomputer  101  transfers all remaining data in the storage medium  106  to the external apparatus  112  via the data transfer I/F  111 , and ends the processing. When the processing ends, the battery  113  is fully charged and the storage medium  106  is empty. 
         [0061]    The following describes an example of displaying a currently charging screen and a currently transferring screen when the digital video camera  100  has been set to the charge prioritizing mode, with reference to  FIG. 4A  and  FIG. 4B . 
         [0062]      FIG. 4A  and  FIG. 4B  show setting screens of the digital video camera  100 ;  FIG. 4A  is directed to a currently charging screen; and  FIG. 4B  is directed to a currently transferring screen. 
         [0063]    When the battery  113  is being charged, a currently charging screen  205 , as shown in  FIG. 4A  and  FIG. 4B , is displayed on the display unit. On the currently charging screen  205 , “currently charging” is displayed in an upper left-hand portion, and the selected “charge prioritizing mode” is displayed in an upper right-hand portion. A process bar is used to give a visual representation of the remaining charge level in the battery  113 , and a value is displayed below the process bar. Note that an available storage capacity of the storage medium  106  is also displayed on the currently charging screen  205  at this point, but with the process bar in a grey-out state. This allows the user to see which of the charge and the data transfer is being performed. 
         [0064]    Conversely, when data is being transferred to the external apparatus  112  via the data transfer I/F  111 , a currently transferring screen  206  is displayed on the display unit. On the currently transferring screen  206 , “currently transferring data” is displayed in an upper left-hand portion, and the selected “charge prioritizing mode” is displayed in an upper right-hand portion. A process bar is used to give a visual representation of the remaining storage capacity in the storage medium  106 , and a value is displayed below the process bar. Note that the amount of remaining charge in the battery  113  is also displayed on the currently transferring screen  206  at this point, but with the process bar in a grey-out state. This allows the user to see which of the charge and the data transfer is being performed. 
         [0065]    As described above, in the digital video camera  100  according to the present embodiment, charge of the battery  113  to the prescribed value and data transfer to the external apparatus  112  to a prescribed value are performed in a fixed period in accordance with control from the microcomputer  101 . As a result, it is possible to secure an amount charge in the battery  113  and a remaining storage capacity in the storage medium  106  that are sufficient to allow image capture, even when only a limited amount of time is available before next use. Moreover, the battery charge and data transfer in the limited amount of time is possible without extra work from the user, an increase in the number of parts the digital video camera  100 , or a rise in cost. Hence, it is possible to solve the problem of the digital video camera  100  becoming unusable due to the battery running out or insufficient remaining storage capacity in the storage medium. 
         [0066]    The second embodiment of the present invention differs from the first embodiment in terms of the digital video camera processing shown in  FIG. 5 . Since other elements of the present embodiment resemble corresponding elements in the above-described first embodiment ( FIG. 1 ), a description of these other elements is omitted. 
         [0067]    In the present embodiment, the camera internal operation when the digital video camera  100   a  has been set to the charge prioritizing mode is described with reference to the flow chart of  FIG. 5 . 
         [0068]      FIG. 5  is a flowchart showing the procedure for the camera internal operation control processing when the digital video camera  100   a  has been set to the data transfer prioritizing mode. 
         [0069]    As shown in  FIG. 5 , at the beginning of the processing in data transfer prioritizing mode set by the user using the operation unit  119 , the microcomputer  101  of the digital video camera  100   a  detects the remaining storage capacity in the storage medium  106  using the storage medium remaining capacity detecting unit  109  in order to perform data transfer. Next, the microcomputer  101  calculates the remaining storage capacity in the storage medium  106  based on a detection result from the storage medium remaining capacity detecting unit  109 , and judges whether the remaining storage capacity of the storage medium  106  is at least the prescribed value (step S 401 ). Here, it is assumed that the prescribed value for the remaining storage capacity of the storage medium  106  is 50% of the total capacity of the storage medium  106 . 
         [0070]    When the remaining storage capacity of the storage medium  106  is less than 50% of the total capacity, the microcomputer  101  begins transferring data to the external apparatus  112  connected to the digital video camera  100   a  via the data transfer I/F  111  (step S 402 ). Data transfer is performed file by file, with one file being the smallest data unit. When the remaining storage capacity of the storage medium  106  exceeds 50% of the total capacity, or has exceeded 50% of the total capacity as a result of data transfer, the microcomputer  101  proceeds to step S 403 . 
         [0071]    Next, the microcomputer  101  checks the amount of charge remaining in the battery  113  using the remaining charge detecting unit  118 . The microcomputer  101  calculates the amount of charge remaining in the battery  113  based on the detection result from the remaining charge detecting unit  118 , and judges whether the amount of charge remaining is at least the prescribed value (step S 403 ). Here is it is assumed that the prescribed value for the amount of charge remaining in the battery  113  is 50% of the fully charged level. 
         [0072]    When the amount of charge remaining in the battery  113  is less than 50% of the fully charged level, the microcomputer  101  charges the battery  113  using the charging circuit  115  for a fixed period, and continues charging in a succession of fixed periods until the amount of charge remaining reaches at least 50% of the fully charged level (step S 404 ). When the amount of charge remaining in the battery  113  exceeds 50% of the fully charged level, or has reached at least 50% of the fully charged level as a result of the charge of the battery  113 , the microcomputer  101  judges that the charge remaining is sufficient, and proceeds to step S 405 . 
         [0073]    For an affirmative judgment in the above-described step  403 , the amount of charge remaining in the battery  113  must exceed 50% of the fully charged level, and the remaining storage capacity of the storage medium  106  must exceed 50% of the total capacity. The microcomputer  101  judges whether non-transferred data is present in the storage unit  106  (step S 405 ). When non-transferred data is present, the microcomputer  101  transfers all remaining data in the storage medium  106  to the external apparatus  112  via the data transfer I/F  111  (step S 406 ). When non-transferred data is absent, the microcomputer  101  proceeds directly to step S 407 . 
         [0074]    Next, the microcomputer  101  judges whether an amount of charge remaining in the battery  113  is the fully charged level (step S 407 ). When the amount of charge remaining is the fully charged level, the microcomputer  101  ends the processing. When the remaining charge is less than the fully charged level, the microcomputer  101  charges the battery  113  using the charging circuit  115  (step S 408 ), and ends the processing. When the processing ends, the battery  113  is fully charged and the storage medium  106  is empty. 
         [0075]    As described above, according to the present embodiment, battery charge and data transfer are possible in a limited period of time without extra work from the user or an increase in the number of parts of the digital camera  100   a , or a rise in cost. Hence, it is possible to solve the problem of the digital video camera  100   a  becoming unusable due to the battery running out or insufficient remaining storage capacity in the storage medium. 
         [0076]    The third embodiment of the present invention differs from the above described first embodiment in terms of the digital video camera processing shown in the flowchart of  FIG. 6 . Since the other elements of the present embodiment resemble corresponding elements in the above-described first embodiment ( FIG. 1 ), a description of these elements is omitted. 
         [0077]    In the present embodiment, camera internal operation, including error processing, when the digital video camera  100   b  has been set to the charge prioritizing mode is described with reference to the flow chart of FIG.  6 A and  FIG. 6B . 
         [0078]      FIG. 6A  and  FIG. 6B  are a flowchart showing a procedure for camera internal operation control processing when the digital video camera  100   b  has been set to the charge prioritizing mode. 
         [0079]    As shown in  FIG. 6A  and  FIG. 6B , at the beginning of processing in the charge prioritizing mode set by the user via the operation unit  119 , the microcomputer  101  of the digital video camera  100   b  detects the amount of charge remaining in the battery  113  using the remaining charge detecting unit  118 . Next, the microcomputer  101  calculates the amount of charge remaining in the battery  113  based on the detection result from the remaining charge detecting unit  118  (step S 501 ). When the battery  113  cannot be charged, the microcomputer  101  proceeds to step S 504 . 
         [0080]    When the check result of step S 501  indicates that the battery  113  can be charged, the microcomputer  101  judges whether the amount of charge remaining in the battery  113  is at least the prescribed value based on the detection result from the remaining charge detecting unit  118  (step S 502 ). When the amount of charge remaining in the battery  113  is less than the prescribed value (i.e. charge is possible), the microcomputer  101  charges the battery  113  for a succession of fixed periods using the charging circuit  115  (step S 503 ). When the amount of charge remaining in the battery  113  is greater than the prescribed value (i.e. charge is not possible), the microcomputer  101  proceeds to step S 504  without performing charge processing. 
         [0081]    Next, the microcomputer  101  checks whether a connection for data transfer between the digital video camera  100   b  and the external apparatus  112  has been established. When the connection with the external apparatus  112  has been established (i.e. data transfer is possible), the microcomputer  101  transfers data to the external apparatus  112  to the external apparatus  112  via the data transfer I/F  111  (step S 505  and step S 506 ) using processing substantially the same as the processing of step S 303  and step S 304  in  FIG. 3 . When the check result of step S 504  indicates that the connection with the external apparatus  112  has not been established (i.e. data transfer is not possible), the microcomputer  101  proceeds to step S 507 . Note that the case when the data transfer is not possible includes when the external apparatus  112  is unable to receive transferred data due to being in the midst of performing a predetermined operation (such as a recording operation on a hard disc recorder) or the like. 
         [0082]    Charge processing is performed from step S 507  to step S 509 . The microcomputer  101  initially checks whether charge of the battery  113  is possible based on the detection result from the remaining charge detecting unit  118  (step S 507 ). When charge is not possible, the microcomputer proceeds to step S 510 . When charge is possible, the microcomputer  101  judges whether the battery  113  is fully charged (step S 508 ). When the battery  113  is not fully charged, the microcomputer  101  performs charge until the battery  113  becomes fully charged, using the charging circuit  115  (step S 509 ). When the judgment result of step S 508  indicates that the battery  113  is fully charged, the microcomputer  101  proceeds to step S 510 . 
         [0083]    Data transfer processing is performed from step S 510  to step S 512 . The microcomputer  101  initially checks whether a connection between the digital video camera  100   b  and the external apparatus  112  has been established (step S 510 ). When the connection with the external apparatus  112  has not been established, the microcomputer returns to the charge processing. If, at this point, the charge processing has already been completed and the battery  113  is fully charged (YES to step S 508  and NO to step S 510 ), the microcomputer  101  skips the charge processing and loops until the connection with external apparatus  112  can be established. When the check result of step S 510  indicates that the connection with the external apparatus  112  has been established, the microcomputer  101  judges whether non-transferred data is present in the storage medium  106  (step S 511 ). When non-transferred data is present, the microcomputer  101  transfers all remaining data in the storage medium  106  to the external apparatus  112  via the data transfer I/F  111  (step S 512 ). When non-transferred data is absent, the microcomputer  101  proceeds directly to step S 513 . 
         [0084]    Arrival at step S 513  indicates that the data transfer has been completed, and so the microcomputer  101  then checks whether the battery  113  is fully charge based on the latest detection result from the remaining charge detecting unit  118  (step S 513 ). When the battery  113  is not fully charged, the microcomputer  101  returns to the charge processing. When the battery  113  is fully charged, the microcomputer  101  ends the processing. 
         [0085]    The following describes examples of errors displayed during processing in the charge prioritizing mode of the digital video camera  100   b , with reference to  FIG. 7A  to  FIG. 7E . 
         [0086]      FIG. 7A  to  FIG. 7E  show examples of errors displayed in the digital video camera  100   b .  FIGS. 7A and 7B  are examples of errors displayed to indicate that battery charge is not possible.  FIG. 7B  to  FIG. 7E  are examples of errors displayed to indicate that data transfer is not possible. 
         [0087]    As shown in  FIG. 7 , one reason for being unable to charge the battery  113  is that the digital video camera  100   b  is not connected to the AC power source via the AC power adaptor  116 . In this case a charge not possible warning screen  207  is displayed on the display unit. Alternatively, when the battery  113  is not fitted to the digital video camera  100   b , a charge not possible warning screen  208  is displayed. 
         [0088]    One reason for being unable to transfer data is that the data transfer I/F  111  of the digital video camera  100   b  is not connected to the external apparatus  112  via a network cable or the like. In this case, a data transfer not possible warning screen  209  is displayed. Alternatively, when the digital video camera  100   b  is connected to the external apparatus  112  but the connected external apparatus  112  has refused data transfer due to being in the midst of a recording or the like, a data transfer not possible warning screen  210  is displayed. When the storage medium  106  is not fitted to the digital video camera  100   b , a data transfer not possible warning screen  211  is displayed. 
         [0089]    As described above, according to the present embodiment, battery charge and data transfer are possible in a limited period of time without extra work from the user, an increase in the number of parts of the digital camera  100   b , or a rise in cost. Hence, it is possible to solve the problem of the digital video camera  100   b  becoming unusable due to the battery running out or insufficient remaining storage capacity in the storage medium. 
         [0090]    The fourth embodiment of the present invention differs from the first embodiment in terms of the digital video camera processing shown in the flowcharts of  FIG. 8A  and  FIG. 8B . Since the other elements of the present embodiment resemble corresponding elements in the above-described first embodiment ( FIG. 1 ), a description of these elements is omitted. 
         [0091]    In the present embodiment, the camera internal operation, including error processing, with the digital video camera  100   c  set to the data transfer prioritizing mode is described with reference to the flow chart of  FIG. 8 . 
         [0092]      FIG. 8A  and  FIG. 8B  are flowcharts showing a procedure for the camera internal operation control processing when the digital video camera  100   c  has been set to the data transfer prioritizing mode. 
         [0093]    As shown in  FIGS. 8A and 8B , at the beginning of processing in the data transfer prioritizing mode set by the user via the operation unit  119 , the microcomputer  101  of the digital video camera  100   c  checks whether the digital video camera  100   c  has established a connection with the external apparatus  112  (step S 601 ). When the connection with the external apparatus  112  has not been established (i.e. data transfer is not possible), the microcomputer  101  proceeds to step S 604  without performing the data transfer processing. When the connection with the external apparatus  112  has been established (i.e. data transfer is possible), the microcomputer  101  detects the remaining storage capacity of the storage medium  106  using the storage medium remaining capacity detecting unit  109 , and judges whether the remaining storage capacity is at least a prescribed value based on the detection result. 
         [0094]    When the remaining storage capacity of the storage medium  106  is less than the prescribed value, the microcomputer  101  performs data transfer to the external apparatus  112  connected to the digital video camera  100   c  via the data transfer I/F  111  (step S 603 ). On the other hand, when the judgment result from step S 602  indicates that the remaining storage capacity of the storage medium  106  exceeds the prescribed value, the microcomputer  101  proceeds to step S 604 . 
         [0095]    Next, the microcomputer  101  checks whether charge of the batter  113  is possible based on the detection result from the remaining charge detecting unit  118  (step S 604 ). When charge of the battery  113  is not possible, the microcomputer  101  proceeds to step S 607 . When charge of the battery  113  is possible, the microcomputer  101  judges whether the amount of charge remaining in the battery  113  is greater than or equal to a prescribed value based on the detection result from the remaining charge detecting unit  118  (step S 605 ). When the amount of charge remaining in the battery  113  is less than the prescribed value, the microcomputer  101  charges the battery  113  for a succession of fixed periods using the charging circuit  115  (step S 606 ). The case that charge is not possible includes when the battery  113  is not fitted to the digital video camera  100   c.    
         [0096]    Data transfer processing is performed from step S 607  to step S 609 . The microcomputer  101  initially checks whether a connection between the digital video camera  100   c  and the external apparatus  112  has been established (step S 607 ). When the connection with the external apparatus  112  has not been established (i.e. data transfer is not possible), the microcomputer  101  proceeds to step S 610 . 
         [0097]    When the check result of step S 607  indicates that the connection with the external apparatus  112  has been established (i.e. data transfer is possible), the microcomputer  101  judges whether non-transferred data is present in the storage medium  106  (step S 608 ). When non-transferred data is absent, the microcomputer  101  proceeds to step S 610 . When non-transferred data is present, the microcomputer  101  transfers all remaining data in the storage medium  106  to the external apparatus  112  via the data transfer I/F  111  (step S 609 ). 
         [0098]    Charge processing is performed from step S 610  to step S 612 . The microcomputer  101  initially checks whether charge of the battery  113  is possible based on the detection result from the remaining charge detecting unit  118  (step S 610 ). When charge of the battery  113  is not possible, the microcomputer  101  returns to the data transfer processing. If, at this point, the data transfer has already been completed and the storage medium  106  is empty (NO to step S 608  and YES to step S 610 ), the microcomputer  101  skips the data transfer processing and loops until charge of the battery  113  becomes possible. 
         [0099]    When the check result of step S 610  indicates that charge is possible, the microcomputer  101  judges whether the battery  113  is fully charged (step S 611 ). When the battery  113  is not fully charged, the microcomputer  101  performs charge until the battery  113  becomes fully charged using the charging circuit  115  (step S 612 ). When the battery  113  becomes fully charged, the microcomputer  101  proceeds to step S 613 . 
         [0100]    Arrival at step S 613  indicates that the battery  113  has been fully charged, and so the microcomputer  101  then checks whether non-transferred data is present in the storage medium  106  (step S 613 ). When non-transferred data is present, the microcomputer  101  returns to the data transfer processing. When non-transferred data is absent, the microcomputer  101  ends the processing. 
         [0101]    As described above, according to the present embodiment, battery charge and data transfer are possible in a limited period of time without extra work from the user, an increase in the number of parts of the digital camera  100   c , or a rise in cost. Hence, it is possible to solve the problem of the digital video camera  100   c  becoming unusable due to the battery running out or insufficient remaining storage capacity in the storage medium. 
         [0102]    In the above-described first to fourth embodiments, although examples in which the prescribed value for the amount of charge remaining in the battery  113  was set to 50% and the prescribed value for the remaining storage capacity in the storage medium  106  was set to 50% of the total capacity were described, the present invention is not limited to these settings. The prescribed value for the amount of charge remaining and the prescribed value for the remaining storage capacity may be set freely to any value within the scope of the present invention. 
         [0103]    The above-described first to fourth embodiments describe examples in which charging and data transfer are realized in a digital video camera capable of setting an order of priority for performing the charge and the data transfer. However the present invention is not limited to such a digital video camera. The present invention may further be applied to a digital video camera not capable of setting the above-described order of priority. In such a digital video camera, the microcomputer judges whether an amount of charge remaining in the battery has reached a first prescribed value, and if the not, performs charge until the amount of charge remaining reaches a second prescribed value. Here, the first prescribed value and the second prescribed value may be the same value. When the amount of charge remaining in the battery has reached the second prescribed value, the microcomputer performs data transfer. When the data transfer is complete, the microcomputer performs charge to a third prescribed value (until the battery is fully charged, for instance). 
         [0104]    In the above-described first to fourth embodiments, the type of the external apparatus  112  connected to the digital video camera is not stated, and there are no particular limits on the type of the external apparatus  112 . Various types of external apparatus can be used, including hard disk recorders and the like. 
         [0105]    The above-described first to fourth embodiments describe examples in which the imaging device of the present application is a digital video camera. However the imaging device of the present invention is not limited to being a digital video camera. The present invention can be applied in electronic cameras other than digital video cameras. 
         [0106]    It is to be understood that the object of the present invention may also be accomplished by supplying a system or an apparatus with a storage medium in which a program code of software which realizes the functions of the above described embodiment is stored, and causing a computer (or CPU or MPU) of the system or apparatus to read out and execute the program code stored in the storage medium. 
         [0107]    In this case, the program code itself read from the storage medium realizes the functions of any of the embodiments described above, and hence the program code and the storage medium in which the program code is stored constitute the present invention. 
         [0108]    Examples of the storage medium for supplying the program code include a floppy (registered trademark) disk, a hard disk, a magnetic-optical disk, a CD-ROM, a CD-R, a CD-RW, DVD-ROM, a DVD-RAM, a DVD-RW, a DVD+RW, a magnetic tape, a nonvolatile memory card, and a ROM. Alternatively, the program may be downloaded via a network. 
         [0109]    Further, it is to be understood that the functions of the above described embodiment may be accomplished not only by executing a program code read out by a computer, but also by causing an OS (operating system) or the like which operates on the computer to perform a part or all of the actual operations based on instructions of the program code. 
         [0110]    Further, it is to be understood that the functions of the above described embodiment may be accomplished by writing a program code read out from the storage medium into a memory provided on an expansion board inserted into a computer or in an expansion unit connected to the computer and then causing a CPU or the like provided in the expansion board or the expansion unit to perform a part or all of the actual operations based on instructions of the program code. 
         [0111]    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 modifications, equivalent structures and functions. 
         [0112]    This application claims priority to Japanese Patent Application No. 2006-262721 filed Sep. 27, 2006, which is herein incorporated by reference in its entirety.