JP4223052B2 - Digital camera - Google Patents

Description

  The present invention relates to a digital camera that forms a cluster from a plurality of sectors and manages recording media in units of clusters.

  Generally, when data such as an image file is recorded on a recording medium such as a memory card by a data recording / reproducing apparatus such as a digital camera, the number of sectors per cluster, that is, the cluster size is PBR (Partition Boot Record) of the recording medium. The recording medium is managed by using two recording units of a cluster and a sector. The size of the cluster is set to the power of 2 of the number of sectors.

In the recording medium, data such as an image file is arranged in units of clusters, and even if the data is 1 byte, one cluster is consumed for the recording. Therefore, useless areas increase as the cluster size increases. However, as the cluster size increases, one data file can be recorded with a smaller number of clusters, and the access speed increases.
As described above, the cluster size and the access speed are in an inversely proportional relationship, and if the cluster size is increased, access can be performed at a high speed. However, when a small file is recorded, a useless area increases. Conversely, if the cluster size is reduced, the useless area is reduced, but the access speed is reduced.

  However, in a portable recording / reproducing apparatus such as a digital camera, the recording medium is formatted with a cluster size determined in advance according to the capacity of the recording medium. In the case where importance is placed on the recordable capacity, or conversely, the recordable capacity of the recording medium is more important than the high-speed access, there is a problem that such user requests are not taken into consideration.

  Therefore, an object of the present invention is to provide a digital camera that can achieve both high speed access and recordable capacity.

A digital camera according to the present invention includes a plurality of interfaces for connecting a plurality of types of recording media having different cluster sizes representing the number of sectors per cluster, and a file recording apparatus for recording an image file on the recording medium in units of clusters. It has. Here, the file recording device
Cluster size acquisition means for acquiring a cluster size from a plurality of types of recording media connected to the plurality of interfaces;
In accordance with the size of the image file to be recorded, the larger the file size, the interface selection means for selecting an interface to which a large cluster size recording medium is connected;
File recording means for recording the image file on a recording medium connected to the selected interface;

  According to the digital camera of the present invention, both high speed access and the recordable capacity of the recording medium can be achieved.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
As shown in FIG. 1, a digital camera (1) according to the present invention includes a CCD (2) for photographing an image and a signal processing unit (3) for performing predetermined signal processing on image data obtained from the CCD (2). And a CPU (4), an image compression processing unit (5) for compressing image data, a built-in memory (6) to store the compressed image data, a card control unit (7), and a user operation A power operation key (8), a display (9), and a card interface (10) are provided. An external memory card (11) can be inserted into the card interface (10).

In the digital camera (1), the external memory card (11) is managed by the FAT file system, and the external memory card (11) inserted into the card interface (10) is changed according to the user's formatting operation. Initialized (reformatted) in a predetermined format.
Thereafter, in image shooting, image data obtained from the CCD (2) is supplied to the signal processing unit (3) and subjected to necessary signal processing, and then stored in the image compression processing unit (5). The compressed image data is written to the external memory card (11) under the control of the card interface (10) with the external memory card (11) inserted into the card interface (10). It is.

FIG. 2 shows a procedure for setting a cluster size when formatting an external memory card. First, in step S1, a menu screen as shown in FIG. 6A is displayed on the display (9). After recognizing that “reformat” is selected from the screen, in step S2, the PBR of the external memory card is displayed. Read the cluster size (initial value) from (Partition Boot Record).
In step S3, the remaining capacity of the external memory card corresponding to the cluster size is calculated from the resolution and compression rate of a predetermined image, and the number of shootable images is calculated from the result.

The remaining capacity X of the external memory card when the external memory card is formatted can be calculated by subtracting the size of the two FAT areas and the size of the root directory area from the total size of the external memory card. . That is, if the total number of sectors in the FAT file system is TS, the number of sectors in each FAT is NF, the number of directory entries in the root directory is RD, and the number of sectors per cluster (cluster size) is SP, one directory Is 32 bytes, and one sector corresponds to 512 bytes. Therefore, the remaining capacity X can be calculated by the following equation 1 in units of sectors.
[Equation 1]
X = (((((TS− (NF × 2 + RD × 32 ÷ 512))
÷ SP) × SP × 512)) ÷ 512)

For example, when the resolution is 1024 × 768 pixels and the compression rate is 50%, the number of shootable images Y can be calculated by the following formula 2.
[Equation 2]
Y = ((X ÷ SP) × SP) ÷ (1024 × 768 × 0.5 ÷ 512)

  Thereafter, in step S4, a high speed / capacity selection screen as shown in FIG. 6B is displayed on the display 9 as a user graphical interface. On this screen, the first display section A for inputting the speed of access to the external memory card and the recordable capacity at what ratio is important by moving the cursor, and the cluster size (unit of used capacity) A second display unit B for displaying and a third display unit C for displaying the number of shootable images are included.

  Subsequently, in step S5 of FIG. 2, it is determined whether the cursor of the first display unit has moved to the high speed side or the capacity side by the user's operation. Thus, if the speed emphasis setting process in step S6 is executed and the process moves to the capacity side, the capacity emphasis setting process in step S7 is executed according to the degree.

In the speed emphasis setting process in step S6, as shown in FIG. 3, it is determined in step S61 whether or not the value twice the current cluster size is 64 or less. If it is determined as YES, step S62 is performed. Then, a value twice as large as the cluster size is set as a new cluster size.
In the capacity emphasis setting process in step S7, as shown in FIG. 4, it is determined in step S71 whether the half value of the current cluster size is 64 or less. In step S72, a value half the cluster size is set as a new cluster size.

For example, when the cursor is moved to the high speed side as shown in the first display section A of FIG. 6C from the screen of FIG. 6B, the cluster size of the second display section B is from 8 [sector / cluster] to 16 The setting is changed to [sector / cluster]. As a result, the number of shootable images on the third display section C decreases from 100 to 70.
As a result, the user can recognize that the cluster size increases while the number of shootable images decreases by placing importance on high-speed access.

Thereafter, in step S8 of FIG. 2, it is determined whether or not the user has performed a determination operation on the format confirmation screen shown in FIG. Here, when the determination operation is not performed, the process returns to step S3 in FIG. 2, and the cluster size is recalculated according to the resetting of the importance of the recordable capacity and the high-speed access by the user's cursor movement. And redisplay, and recalculate and redisplay the number of shootable images.
Then, when it is determined in step S8 that the user has performed the determination operation, the process proceeds to step S9, and the cluster size displayed on the second display unit is written in the PBR of the external memory card, thereby the cluster size. Format the external memory card with.

  According to the digital camera of the present invention, the display of the high speed / capacity selection screen shown in FIG. 6 (b) allows the user to confirm the cluster size and the number of shootable images obtained in the format of the external memory card. In addition, as shown in FIG. 6C, by re-entering the high speed of access by moving the cursor key and the importance of the recordable capacity, a format that satisfies the requirements for the high speed of access and the number of storable images can be performed.

FIG. 5 shows a data recording operation in a digital camera having two interfaces for connecting two types of external memory cards having different cluster sizes.
First, in step S11, after obtaining the cluster size from the two types of external memory cards connected to the two interfaces, it is determined in step S12 whether or not a recording start operation has been performed. If it is determined YES, the process proceeds to step S13, and it is determined whether or not the size of the image file to be recorded is larger than a predetermined value.

  When it is determined that the file size is larger than the predetermined value, the process proceeds to step S14, where an image file is recorded for an external memory card having a large cluster size, and the file size is smaller than the predetermined value. If it is determined, the process proceeds to step S15, and an image file is recorded for an external memory card having a small cluster size.

  According to the digital camera, the external memory card is automatically selected according to the size of the image file to be recorded on the external memory card, and the large image file is recorded on the external memory card having a large cluster size. Since a small image file is recorded on an external memory card with a small cluster size, a recording operation that achieves both high speed access and recordable capacity is realized.

  In a digital camera, it is also possible to determine the optimum cluster size based on the file size calculated from the image resolution and compression rate, and format the external memory card with the cluster size. For example, if the file size is 512 bytes or less, the cluster size is 1; if the file size is 1024 bytes or less, the cluster size is 2, and so on ... If the file size is 32768 bytes or less, the cluster size is 64 Is possible.

It is a block diagram which shows the structure of the digital camera which concerns on this invention. 4 is a flowchart showing a format setting procedure of an external memory card in the digital camera according to the present invention. It is a flowchart which shows a speed emphasis setting procedure. It is a flowchart which shows a capacity | capacitance importance setting procedure. It is a flowchart showing the data recording operation | movement of a digital camera. It is a figure which illustrates the graphical user interface displayed on the display of the digital camera which concerns on this invention.

Explanation of symbols

(1) Digital camera
(2) CCD
(3) Signal processor
(4) CPU
(5) Image compression processor
(6) Built-in memory
(7) Card controller
(8) Operation keys
(9) Display
(10) Card interface
(11) External memory card

Claims (1)

In a digital camera comprising a plurality of interfaces for connecting a plurality of types of recording media having different cluster sizes representing the number of sectors per cluster, and a file recording device for recording image files on the recording media in units of clusters. The recording device
Cluster size acquisition means for acquiring a cluster size from a plurality of types of recording media connected to the plurality of interfaces;
In accordance with the size of the image file to be recorded, the larger the file size, the interface selection means for selecting an interface to which a large cluster size recording medium is connected;
A digital camera comprising file recording means for recording the image file on a recording medium connected to the selected interface.

Images