JP4166148B2 - Image recording device - Google Patents

Description

  The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus which is applied to, for example, a digital camera and records an image signal on a recording medium whose storage area is divided into a plurality of unit areas.

An example of a conventional image recording apparatus of this type is disclosed in Patent Document 1. In this prior art, a FAT (File Allocation Table) method is adopted as a file management method for a recording medium. When an unused recording medium is attached to the digital camera, the number of sectors forming one cluster is changed from “4” to “16”. As a result, the time required for recording the image data can be shortened.
Patent No. 3177491 [H04N 5/91, 5/907]

  However, when the cluster size is increased, the use efficiency of the recording medium is lowered. The problem of this reduction in use efficiency becomes more prominent as the capacity of the recording medium is smaller, in other words, the smaller the number of images that can be recorded on the recording medium, that is, the smaller the number of recordable sheets. Nevertheless, in the prior art, the cluster size is changed to “16” regardless of the recording capacity or the number of recordable sheets. For this reason, in the prior art, although it is possible to shorten the time required for recording, it is impossible to prevent a decrease in the usage efficiency of the recording medium.

  Therefore, a main object of the present invention is to provide an image recording apparatus capable of both reducing the time required for recording and preventing the decrease in the use efficiency of the recording medium.

An image recording apparatus according to claim 1 is an image recording apparatus for recording image data on a recording medium in which the recording area is divided into a plurality of unit areas and in which the unit areas in the empty state can be discretely distributed. detecting means for detecting the capacitance, calculating means for calculating a recordable number image data of the recording medium based on the volume detected by the detection means, and calculating means are recordable image data number as a unit area larger calculated by A setting means for setting a large size is provided.

The image data is recorded on a recording medium in which the recording area is divided into a plurality of unit areas and the empty unit areas can be distributed discretely . Detecting means detects the capacity of the recording medium, calculating means calculates the recordable number image data of the recording medium based on the detected capacitance, setting means calculated as a unit area recordable image number data is larger was Increase the size of.

When the number of recordable image data is large, a decrease in use efficiency of the recording medium is not a problem. For this reason, the size of the unit area is set to a large value in order to shorten the recording time. On the other hand, when the number of recordable image data is small , the use efficiency of the recording medium should be more important than the recording time, and the size of the unit area is set to a small value. As a result, it is possible to achieve both the reduction of the time required for recording and the prevention of lowering the use efficiency of the recording medium.

The number of recordable image data depends on the size of the image data, and this size varies depending on subsequent factors (for example, the resolution of the image sensor and the default compression rate of the codec). Furthermore, the number of recordable image data is an important factor in determining which of the recording time and the usage efficiency of the recording medium is important. Therefore, the calculated recordable image number data based on the capacity of the record medium, the size of the unit area is set based on the recording image capacity data calculated. As a result, the shortening of the time required for recording and the prevention of a decrease in the use efficiency of the recording medium are most appropriately achieved.

The image recording apparatus according to an invention of claim 2 depends on claim 1, the image data is compressed image data compressed with the goal of a predetermined size, calculation means based on the capacity of the recording area and the target size recording The number of possible image data is calculated. By setting the target size of the compressed image data, the recordable number of sheets can be easily calculated .

According to a third aspect of the present invention, a digital camera includes the image recording apparatus according to the first or second aspect .

An image recording method according to claim 4 is an image recording method for recording image data on a recording medium in which a recording area is divided into a plurality of unit areas and empty unit areas can be distributed discretely. ) Detecting the capacity of the recording medium , ( b) calculating the number of recordable image data of the recording medium based on the capacity detected in step (a) , and (c) recording calculated in step (b) The larger the number of possible image data , the larger the unit area size is set. Similar to the first aspect, it is possible to achieve both the reduction of the time required for recording and the prevention of the decrease in the usage efficiency of the recording medium.

According to the present invention, when the number of recordable image data is large, the size of the unit area is set to a large value, and when the number of recordable image data is small , the size of the unit area is set to a small value. It is possible to achieve both shortening of the time required and prevention of lowering the use efficiency of the recording medium.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  Referring to FIG. 1, a digital camera 10 of this embodiment includes an optical lens 12. The optical image of the subject enters the light receiving surface of an image sensor 14 such as a CCD imager via the optical lens 12. The light receiving surface is covered with a color filter (not shown) having a primary color Bayer arrangement, and the charges generated by each of a plurality of light receiving elements (pixels) formed on the light receiving surface, that is, pixel signals are R, G and B Only one color information is included.

  In this embodiment, a CCD imager is used as the image sensor 14, but a CMOS imager may be used instead.

  When the main power is turned on, a through image display process is executed. First, the CPU 34 instructs the TG (Timing Generator) 40 to repeat thinning readout. The TG 40 performs thinning readout on the image sensor 14 at a frame rate of 30 fps. As a result, a raw image signal with reduced vertical resolution is read from the image sensor 14 in a raster scanning manner. The output low-resolution raw image signal has color information of R, G, R, G,... On even lines and color information of G, B, G, B,.

  The CDS / AGC circuit 16 performs noise removal and gain adjustment on the raw image signal of each frame output from the image sensor 14, and the A / D converter 18 converts the raw image signal subjected to such processing into a digital signal. Convert to raw image data. The converted raw image data is given to the signal processing circuit 20 and subjected to signal processing such as white balance adjustment, color separation, horizontal thinning, and YUV conversion. The YUV data obtained by the YUV conversion is written into the SDRAM 24 by the memory controller 22.

  The video encoder 26 reads the YUV data of each frame from the SDRAM 24 through the memory controller 22, and converts the read YUV data into an NTSC composite video signal through a reduction zoom process. The converted composite video signal is given to the LCD 28. As a result, a real-time moving image of the subject, that is, a through image is output from the LCD 28.

  The number of effective pixels of the image sensor 14 is about 2 million, and the number of horizontal pixels and the number of vertical pixels are “1600” and “1200”, respectively. As will be described later, the YUV data corresponding to the still image of the subject is compressed and recorded on the recording medium 38. At this time, the compression rate according to the target file size is set in the JPEG codec 30.

  In this embodiment, one of the first resolution (= 1600 pixels × 1200 pixels) and the second resolution (= 640 pixels × 480 pixels) can be selected as the resolution of the still image. A plurality of compression ratios are prepared for each resolution.

  In the first resolution shooting mode, the first compression ratio (= 0), the second compression ratio (= 5.2), the third compression ratio (= 8.2), and the fourth compression ratio (= 13.4). Either one can be selected. When the first compression rate is selected, a still image file having the first file size (= 5.76 MB) is created, and when the second compression rate is selected, the still image file having the second file size (= 1.1 MB). Is created. When the third compression rate is selected, a still image file having the third file size (= 700 KB) is created. When the fourth compression rate is selected, a still image file having the fourth file size (= 430 KB) is created. Is done.

  In the second resolution shooting mode, one of the fifth compression ratio (= 7.7) and the sixth compression ratio (= 13.2) can be selected. When the fifth compression rate is selected, a still image file of the fifth file size (= 120 KB) is created, and when the sixth compression rate is selected, a still image file of the sixth file size (= 70 KB) is created. .

  The desired resolution and compression rate are selected by operating the resolution selection button 42 and the compression rate selection button 44.

  When the shutter button 32 is operated in a state where the shooting mode is selected and the first resolution is selected, the CPU 34 instructs the TG 40 to execute all pixel reading. The TG 40 reads out all pixels of one frame (one screen) to the image sensor 14, and as a result, a high-resolution raw image signal is output from the image sensor 14 in a raster scanning manner. The output raw image signal has color information of R, G, R, G,... On even lines and color information of G, B, G, B,.

  The raw image signal read in response to the operation of the shutter button 32 is subjected to the same processing as described above by the CDS / AGC circuit 16, the A / D converter 18, and the signal processing circuit 20. However, horizontal thinning is omitted, and the signal processing circuit 20 outputs high-resolution YUV data. The output YUV data is written into the SDRAM 24 via the memory controller 22. The video encoder 26 reads the high-resolution YUV data stored in the SDRAM 24 through the memory controller 22 and converts the read YUV data into a composite video signal in the NTSC format through reduction zoom. As a result, a still image of the subject at the time when the shutter button 32 is operated, that is, a freeze image is output from the LCD 28.

  Further, the CPU 34 gives a compression command to the JPEG codec 30 when any one of the second compression ratio to the fourth compression ratio is selected. The compression instruction includes information indicating the selected compression rate. The JPEG codec 30 reads YUV data from the SDRAM 24 through the memory controller 22, performs JPEG compression on the read YUV data according to a desired compression ratio, and writes the compressed YUV data, that is, JPEG data, into the SDRAM 24 through the memory controller 22. The CPU 34 reads the JPEG data stored in the SDRAM 24 through the memory controller 22 and records a still image file storing the read JPEG data on the recording medium 38 through the I / F 36.

  When the first compression rate (= 0) is selected, the compression process is not necessary. The CPU 34 reads the YUV data stored in the SDRAM 24 through the memory controller 22 and records the still image file storing the YUV data on the recording medium 38 via the I / F 36.

  The recording medium 38 is detachable and is connected to the I / F 36 when mounted. The recording medium 38 adopts the FAT system as a file management system. The recording area is divided into a plurality of clusters, and free clusters can be distributed discretely. Still image files are distributed and written in a plurality of clusters.

  When the second resolution is selected, the CPU 34 instructs the TG 40 to execute thinning-out reading in response to the operation of the shutter button 32. The TG 40 reads out the image sensor 14 for one frame period. As a result, a low-resolution raw image signal is output from the image sensor 14 in a raster scanning manner. The number of vertical lines of the raw image signal output from the image sensor 14 by the thinning readout is ¼ of the number of vertical lines of the raw image signal output from the image sensor 14 by the all pixel readout. However, the output raw image signal has color information of R, G, R, G,... On even lines and color information of G, B, G, B,.

  The raw image signal read in response to the operation of the shutter button 32 is subjected to the same processing as described above by the CDS / AGC circuit 16, the A / D converter 18, and the signal processing circuit 20. When the second resolution is selected, horizontal thinning processing is executed in the signal processing circuit 20, and the number of horizontal pixels is reduced to ¼. The signal processing circuit 20 outputs low-resolution YUV data. This YUV data is written into the SDRAM 24 via the memory controller 22. The low-resolution YUV data stored in the SDRAM 24 is then applied to the video encoder 26 via the memory controller 22 and converted into an NTSC format composite video signal through reduction zoom. As a result, a still image (freeze image) of the subject when the shutter button 32 is operated is output from the LCD 28.

  Further, the CPU 34 gives a compression command to the JPEG codec 30 when the shutter button 32 is operated. The compression instruction includes information indicating either the fifth compression ratio or the sixth compression ratio. The JPEG codec 30 reads low-resolution YUV data from the SDRAM 24 through the memory controller 22, performs JPEG compression on the read YUV data, and writes the JPEG data to the SDRAM 24 through the memory controller 22. The CPU 34 reads the JPEG data stored in the SDRAM 24 through the memory controller 22 and records the read JPEG data on the recording medium 38 through the I / F 36.

  When the playback mode is selected, the file name of the still image file recorded on the recording medium 38 is displayed on the LCD 28. When the user selects a desired file name, the JPEG data or YUV data stored in the selected still image file is read from the recording medium 38 by the CPU 34. The read JPEG data or YUV data is written into the SDRAM 24 by the memory controller 22.

  When the data stored in the SDRAM 24 is JPEG data, a decompression command is given from the CPU 34 to the JPEG codec 30. The JPEG codec 30 reads JPEG data from the SDRAM 24 through the memory controller 22, performs JPEG decompression on the read JPEG data, and writes the decompressed YUV data into the SDRAM 24 through the memory controller 22.

  The YUV data stored in the SDRAM 24 is given to the video encoder 26 via the memory controller 22. The video encoder 26 converts the applied YUV data into a composite video signal of the NTSC system through reduction zoom, and provides the converted composite video signal to the LCD 28. As a result, the reproduced still image is displayed on the LCD 28.

  As described above, the recording medium 34 adopts the FAT system, and still image files are distributed and managed by a plurality of clusters. Here, if the cluster size is large, the file can be managed by a small number of clusters. However, if the size of the still image file is small, the area (sector) that is not used increases, and the use efficiency of the recording medium 38 decreases. On the other hand, if the cluster size is reduced, the use efficiency of the recording medium 38 can be prevented from decreasing, but the number of clusters for managing one still image file increases, and it takes time to write / read the file.

  For example, when storing a still image file of the third file size (= 700 Kbytes) on a recording medium having a capacity of 64 Mbytes, when the cluster size is set to 16 Kbytes, one still image file is stored. The required number of clusters is “44 (= 700 Kbytes / 16 Kbytes)”, and the number of recordable sheets is “90 (= 64 Mbytes / (16 Kbytes * 44 clusters))”. If the cluster size is set to 32 Kbytes, the number of clusters required to store one still image file is “22 (= 700 Kbytes / 32 Kbytes)”, and the recordable number is “90 (= 64 Mbyte / byte). (32 Kbytes * 22 clusters)) ”.

  On the other hand, when storing a still image file of the sixth file size (= 70 Kbytes) on a recording medium having a capacity of 64 Mbytes, if the cluster size is set to 8 Kbytes, one still image file is stored. The required number of clusters is “9 (= 70 Kbytes / 8 Kbytes)”, and the number of shootable images is “888 (= 64 Mbytes / (8 Kbytes × 9 clusters))”. When the cluster size is set to 16 Kbytes, the number of clusters necessary for storing one still image file is “5 (= 70 Kbytes / 16 Kbytes)”, and the number of shootable images is “800 (= 64 Mbyte / byte). (16 Kbytes * 5 clusters)) ”. Further, when the cluster size is set to 32 Kbytes, the number of clusters necessary for storing one still image file is “3 (= 70 Kbytes / 32 Kbytes)”, and the recordable number is “666” (= 64 Mbytes / byte). (32 Kbytes * 3 clusters)) ”.

  That is, if the file size is large, the number of recordable images does not decrease even if the cluster size is increased, and the writing speed is increased by increasing the cluster size. Similarly, if the file size is small, the writing speed does not decrease even if the cluster size is reduced, and the reduction of the recordable number is avoided by reducing the cluster size.

  On the other hand, if the cluster size is increased when the file size is small, the writing speed is fast, but the number of recordable sheets may be reduced. In addition, if the cluster size is reduced when the file size is large, a decrease in the number of recordable sheets can be avoided, but the writing speed becomes slow.

  By the way, in practice, if the number of recordable sheets, that is, the recording capacity is originally large, a decrease in the number of recordable sheets, that is, a decrease in use efficiency of the cluster is not a big problem.

  In consideration of the above characteristics, in this embodiment, the number of recordable images is calculated based on the size of the still image file created under the default shooting conditions and the capacity of the recording medium 38, and the calculated recordable The recording medium 38 is formatted with a cluster size corresponding to the number of sheets.

  Specifically, if the number of recordable sheets is equal to or greater than the first threshold (= 100), the cluster size is determined to be the first size (= 32 Kbytes) with emphasis on the file writing speed. That is, if the number of recordable sheets is 100 or more, it is considered that a decrease in the usage efficiency of the recording medium 34 is not a big problem, and the cluster size is increased. If the number of recordable sheets is less than the first threshold and greater than or equal to the second threshold (= 50), the cluster size is set to the second size (=) with emphasis on both the file writing speed and the usage efficiency of the recording medium 38. 16K bytes). Further, if the recordable number is less than the second threshold value, the cluster size is determined to be the third size (= 8 Kbytes) with emphasis on the use efficiency of the recording medium 38 rather than the writing speed.

  That is, the larger the recordable number, the larger the cluster size is determined. Conversely, the smaller the recordable number, the smaller the cluster size is determined. The determination of the cluster size according to the recordable number of sheets enables the use suitable for each recording medium.

  When the execution of the format process according to the FAT system is instructed, the CPU 38 determines the cluster size according to the flowchart shown in FIG. First, in step S1, a still image file size corresponding to the default mode is specified. In this embodiment, the first resolution and the third compression ratio are the default resolution and compression ratio, and the third file size is specified as the default file size. In step S3, the recording capacity of the external memory, that is, the recording medium 38 is detected, and in step S5, the recordable number of sheets is calculated. Specifically, the recordable number of sheets is calculated by dividing the capacity of the recording medium 38 by the third file size. Subsequently, the recordable number of sheets is determined in steps S7 and S11.

  If the recordable number is “100” or more, the process proceeds from step S7 to step S9, where the size of one cluster is defined as 32 Kbytes, and the recording medium 38 is formatted. If the number of recordings is “50” or more and less than “100”, the process proceeds from step S11 to step S13, and the size of one cluster is defined as 16K bytes, and the recording medium 38 is formatted. If the recordable number is less than “50”, the process proceeds from step S11 to step S15, and the size of one cluster is defined as 8 Kbytes, and the recording medium 38 is formatted. When formatting is completed, the process is terminated.

  According to this embodiment, since the cluster size is determined based on the recordable number of sheets calculated based on the file size and the capacity of the recording medium, the time required for recording is shortened and the use efficiency of the recording medium 38 is decreased. Both prevention can be achieved.

  The digital camera 10 of another embodiment shown in FIG. 3 is the same as the above-described embodiment except that it has two shooting modes, a still image shooting mode and a moving image shooting mode. Therefore, duplicate description is omitted.

  Note that the still image shooting mode is a mode in which a still image of a subject is recorded every time the shutter button 32 is pressed, as described above. The moving image shooting mode is a mode for recording a moving image of a subject in a period according to the pressing of the shutter button 32.

  Referring to FIG. 3, the digital camera 10 according to another embodiment further includes a mode switching button 46 for switching the shooting mode between the still image shooting mode and the moving image shooting mode. When the still image capturing mode is selected by the mode switching button 46, a still image of the subject is captured according to the above-described operation.

  On the other hand, when the shutter button 32 is operated in a state where the moving image shooting mode is selected by the mode switching button 46, the CPU 34 instructs the TG 40 to repeat the main exposure and the thinning readout according to the predetermined resolution. The TG 40 supplies a timing signal corresponding to this command to the image sensor 14. As a result, a raw image signal according to a predetermined resolution is output from the image sensor 14 every frame period.

  The raw image signal of each frame output from the image sensor 14 is input to the A / D conversion circuit 18 through processing by the CDS / AGC circuit 16 and converted into raw image data. The converted raw image data is subjected to the same processing as described above by the signal processing circuit 20, and the YUV data of each frame output from the signal processing circuit 20 is written into the YUV data area 24 a of the SDRAM 24 by the memory controller 22.

  When a compression command is given from the CPU 34, the JPEG codec 30 reads YUV data from the YUV data area 24a, performs JPEG compression on the read YUV data, and converts the generated JPEG data into the JPEG data area 24b of the SDRAM 24. Write to.

  Such compression processing is continued until the shutter button 32 is operated again. That is, the compression process is repeated from the time when the shutter button 32 is first operated until the shutter button 32 is operated again, and a plurality of frames of JPEG data is accumulated in the JPEG data area 24b. The accumulated JPEG data is read by the memory controller 22 and recorded on the recording medium 38 via the I / F 36. As a result, a movie file (QuickTime file) including JPEG data of a plurality of frames is created in the recording medium 38.

  When the reproduction mode is selected, the still image file or movie file recorded on the recording medium 38 is reproduced. When a still image file is selected, the still image is displayed on the LCD 28 as described above. When the movie file is selected, the JPEG data of each frame stored in the movie file is periodically subjected to the same processing as that for still image reproduction. As a result, the moving image is displayed on the LCD 28.

  In the moving image shooting mode, the frame rate of the image sensor 14 can be arbitrarily set. That is, by operating the frame rate selection button 48, either the first frame rate (= 15 fps) or the second frame rate (= 30 fps) can be selected.

  Further, in the moving image shooting mode, the third resolution (= horizontal 640 pixels × vertical 480 pixels), the fourth resolution = horizontal 320 pixels × vertical 240 pixels) or the fifth resolution (= horizontal 160 pixels × vertical 120 pixels) is selected. The seventh compression ratio (= 10.8) or the eighth compression ratio (= 20.4) can be selected for each resolution.

  For example, when 30 fps and the third resolution are selected, a moving image can be recorded for 42 seconds on the 64 Mbyte recording medium 38. In video recording, it is necessary to consider the recording bit rate. The recording bit rate of this embodiment is 12.19 Mbps (= 64 Mbytes / 42 seconds × 8 bits). Then, when 15 fps and the third resolution are selected, the recordable time is extended by a factor of two. When 30 fps and the fourth resolution are selected, the recordable time is extended by four times.

  In this embodiment, conditions for moving image recording according to 30 fps and the third resolution are the strictest, and high-speed accessibility is imposed on the recording medium 38 under these conditions. That is, when a moving image shooting function is provided, it is necessary to determine the cluster size in consideration of the recording bit rate.

  When the recordable number is equal to or larger than the first threshold, the size of one cluster is defined as 64 Kbytes (fourth size), and the recording medium 38 is formatted. If the recordable number is less than the first threshold and greater than or equal to the second threshold, the size of one cluster is defined as the first size and the recording medium 38 is formatted. As a result, the recording speed can be increased.

  Specifically, the CPU 34 executes processing according to the flowchart shown in FIG. However, since the process shown in FIG. 4 is substantially the same as the process shown in FIG. 2, only different parts will be described.

  Referring to FIG. 4, if “YES” in the step S7, that is, if the number of shootable images is 100 or more, the size of one cluster is defined as 64K bytes (fourth size) in a step S9 ′, and the recording medium 38 is formatted. If “YES” in the step S11, that is, if the number of shootable images is 50 or more and less than 100, the size of one cluster is defined as 32 Kbytes (first size) in the step S13 ′, and the recording medium 38 is formatted. Is done. Both of steps S9 ′ and S13 ′ emphasize the writing speed in the moving image shooting mode. If the number of shootable images is less than 50, formatting is performed by defining one cluster as the third size in step S15 in order to emphasize the use efficiency of the recording medium 38.

  According to this embodiment, when the digital camera 10 has a moving image shooting function, the cluster size is determined in consideration of the moving image recording bit rate. As a result, it is possible to achieve both the increase in the recording speed of moving images or still images and the prevention of a decrease in the usage efficiency of the recording medium.

  The digital camera 10 of the other embodiment shown in FIG. 5 is the same as the embodiment of FIG. 3 except that the CPU 34 executes processing according to the flowchart shown in FIG.

  Referring to FIG. 6, the recording capacity of recording medium 38 is detected in step S3, and the detected recording capacity is determined in steps S7 'and S11'. If the recording capacity is 64 Mbytes, the process proceeds from step S7 'to step S9', and the size of one cluster is defined as 64K bytes, and the recording medium 38 is formatted. If the recording number is 32 Mbytes or more and less than 64 Mbytes, the process proceeds from step S11 ′ to step S13 ′, and the size of one cluster is defined as 16 Kbytes, and the recording medium 38 is formatted. Further, if the recordable number is less than 32 Mbytes, the process proceeds from step S11 ′ to step S15, and the size of one cluster is defined as 8 Kbytes, and the recording medium 38 is formatted. When formatting is completed, the process is terminated.

  According to this embodiment, since the cluster size is determined based on the capacity of the recording medium, it is not necessary to detect the file size and calculate the number of recordable sheets, shortening the time required for recording and using the recording medium 38. Prevention of the reduction in efficiency is realized by a simple method. This embodiment also pays attention to the fact that if the capacity of the recording medium 38 is large, a decrease in the use efficiency of the cluster is not a big problem.

  In the above-described embodiment, the recordable number of sheets is calculated based on the default file size. However, the file size used for the calculation may be arbitrarily selected according to the user's preference. Further, the processing according to the flowchart shown in FIG. 6 may be applied to the embodiment in FIG.

It is a block diagram which shows one Example of this invention. It is a flowchart which shows the format process of CPU applied to the FIG. 1 Example. It is a block diagram which shows the other Example of this invention. It is a flowchart which shows the format process of CPU applied to the FIG. 3 Example. It is a block diagram which shows the other Example of this invention. It is a flowchart which shows the format process of CPU applied to the FIG. 3 Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Digital camera 14 ... Image sensor 20 ... Signal processing circuit 22 ... Memory controller 24 ... SDRAM
30 ... JPEG codec 34 ... CPU
42 ... Resolution selection button 44 ... Compression rate selection button 46 ... Mode selection button 48 ... Frame rate selection button

Claims (4)

In an image recording apparatus for recording image data on a recording medium in which a recording area is divided into a plurality of unit areas and in which unit areas in an empty state can be discretely distributed,
Detecting means for detecting the capacity of the recording medium;
Recordable calculating means for calculating an image data number, and size set to be large for the larger recordable image number data calculated by said calculating means the unit area of said detecting means and the recording medium based on the detected capacitance by An image recording apparatus comprising: setting means for performing The image data is compressed image data compressed with a predetermined size as a target,
The calculating means calculates the recordable number image data on the basis of the capacity and the target size of the recording area, the image recording apparatus according to claim 1. A digital camera comprising the image recording apparatus according to claim 1 . An image recording method for recording image data on a recording medium in which a recording area is divided into a plurality of unit areas and empty unit areas can be distributed discretely,
(a) detecting the capacity of the recording medium ;
( b) calculating the number of recordable image data of the recording medium based on the capacity detected in the step (a) ; and
(c) An image recording method in which the size of the unit area is set larger as the number of recordable image data calculated in the step (b) is larger.

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