JP3081585B2 - Digital camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera and, more particularly, to a digital camera for recording, for example, image data containing captured image data and image data management information on a recording medium.

[0002]

2. Description of the Related Art An example of a conventional digital camera of this type is disclosed in Japanese Unexamined Patent Application Publication No.
No. 284700 [H04N5 / 907, 5 / 765,5
/ 781, 5/91]. In this conventional technique, display permission / non-permission is set for image data recorded in a flash memory so as to prevent the image data from being viewed by others.

[0003]

However, the display permission / non-permission information is associated only with the address of the image data,
This does not mean that display permission / non-permission information is included in the image data. That is, the image data itself is configured according to the JPEG format, and the display permission / non-permission information is managed separately from the image data. For this reason, if the flash memory is directly accessed from the outside by general-purpose software compatible with JPEG, the display permission / non-permission information does not make sense and the image data is easily reproduced.

Therefore, the main object of the present invention is to
An object of the present invention is to provide a digital camera that can prevent reproduction of image data even when accessed by general-purpose software compatible with PEG.

[0005]

According to a first aspect of the present invention, there is provided a digital camera for recording an image file containing photographed image data and management information of the image data on a recording medium. Instruction means, change means for changing the contents of the management information based on the reproduction prohibition instruction, setting means for setting a password, and writing means for writing the set password to an image file, the image data is compressed in JPEG format
Includes original image data and thumbnail image data, the management information includes a second marker Huffman coding table corresponding to the first marker and the thumbnail image data of the Huffman encoding table corresponding to the original image data, changing means A digital camera including at least content changing means for changing the content of a first marker .

[0006]

[Function] Do you want to protect the LCD?
When "S NO" is displayed, the operator
When "S" is selected, the value of the marker "DHT" written in the image file is rewritten.
This is the start marker of the Huffman coding table area. When the operator sets a password, the password is written in the image information area of the image file. Marker "D
As a result of rewriting the value of “HT”, the image file is JP
EG format will not be satisfied. That is, the image file is protected from being reproduced.

[0007]

According to the present invention, the content of the management information is changed based on the reproduction prohibition instruction.
It is possible to prevent image data from being reproduced by EG-compatible general-purpose software. The above and 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.

[0008]

Referring to FIG. 1, a digital camera 10 of this embodiment includes a lens 12. FIG. The light image incident from the lens 12 is transmitted through a color filter (not shown) to the CC.
The D imager 14 is irradiated. When the operator switches the mode setting switch 46 to the camera side, the system controller 42 sets the CPU 28 to the camera mode. The CPU 28 causes the CCD imager 14 to perform so-called mixed pixel reading in order to output a moving image from the monitor 34. The pixel signal output from the CCD imager 14 is supplied to a CDS / AGC circuit 16. CDS
/ AGC circuit 16 performs well-known noise removal and level adjustment on the input pixel signal, and performs CDS / AGC circuit 1
The A / D converter 18 converts the pixel signal processed by 6 into digital data, that is, pixel data. The first signal processing circuit 20 generates Y, U, and V data from the pixel data output from the A / D converter 18.

The generated Y, U and V data are written to a memory area 24a of a DRAM 24 via a bus 22, and then read. That is, the data output from the first signal processing circuit 20 is progressive scan data, and an image cannot be displayed on the LCD 34 of the interlace scan system as it is. Therefore, the memory control circuit 26 temporarily writes the Y, U, and V data into the memory area 24a, and thereafter, the same memory control circuit 2
6 reads out Y, U and V data in an interlaced scan mode.

When outputting a moving image, the second signal processing circuit 30
Predetermined horizontal interpolation and vertical interpolation are performed on the Y, U, and V data (moving image data) read from the DRAM 24 so as to match the display screen size of the LCD 34. Second
The moving image data output from the signal processing circuit 30 is then converted into an analog signal by the D / A converter 32, applied to the LCD 34, and output from the output terminal 36. As a result, a moving image is displayed on the LCD 34.

When the operator presses the shutter button 40 in the camera mode, the system controller 42
The CCD imager 14 is controlled so as to perform so-called all-pixel reading. The CCD imager 14 outputs a pixel signal for each line by a progressive scan method.
The CDS / AGC circuit 16 performs noise removal and level adjustment on the pixel signal in the same manner as described above, and the A / D converter 18 converts the pixel signal from the CDS / AGC circuit 16 into digital data, that is, pixel data. The CCD imager 14 is disabled after outputting pixel signals for one frame, and the pixel data for one frame generated by the A / D converter 18 is directly processed without being processed by the first signal processing circuit 20. It is given to the bus 22. Then, the pixel data for one frame is written into the memory area 24a by the memory control circuit 26.

The CPU 28 converts the image data stored in the memory area 24a into a YUV image using the work area 24b.
After conversion, the converted Y, U and V data, that is, the photographed image data, are compressed in accordance with the JPEG format, and the compressed data is stored in an image file. CPU28
Records the image file created in this way on the memory card 46. By the above-mentioned YUV conversion,
Y, U, and V data are obtained for each of all pixels.

The memory control circuit 26 reads out image data from the memory area 24 a by an interlaced scan method and supplies the image data to the second signal processing circuit 30. When the shutter button 40 is pressed, the second signal processing circuit 30 performs YUV conversion on the input image data, and finally the LCD 3
4 outputs a photographed image (freeze image). When the mode setting switch 46 is switched to the reproduction side, the reproduction mode is set. At this time, the CPU 28 copies the desired image file to the work area 24b, and then adds the JPE to the compressed photographed image data (original image data).
Decompression processing is performed according to the G format. The decompressed captured image data is expanded in the memory area 24a, and thereafter read out by the interlaced scan method. The second signal processing circuit 30 performs horizontal interpolation and vertical interpolation on the Y, U, and V data read from the memory area 24a, and as a result, a reproduced image is displayed on the LCD 34.

The thumbnail on / off switch 48
When the playback mode is set while is turned on, nine image files are copied to the work area 24b, and decompression processing is performed on the compressed thumbnail image data stored in each image file. As a result, 9
One thumbnail image is displayed. When a predetermined character is displayed on the LCD 34 on the screen in the reproduction mode, the character generator 38 is activated and the switch SW1 is switched at a predetermined timing.

Each image file recorded on the memory card 46 is configured as shown in FIG. “SO
"I" is a start marker of the image file.
“0” and “APP12” are start markers of the thumbnail image data area and the image information area, respectively, according to the applicant's own standard, and “DQT” is a start marker of the quantization table data area, and “SOF”. "
Is a start marker of a parameter area related to a frame, and “DHT” is a start marker of a Huffman coding table data area. "SOS" is the start marker of the parameter area for the component, and "EOS"
OI "is an end marker of the image file. A compressed data area is provided following the parameter area relating to the component.

The number of pixels of the image data is written in the parameter area relating to the frame. If the number of pixels is 640 pixels × 480 lines, this information means that the resolution is VGA, and if the number of pixels is 1024 pixels × 768 lines, this information means that the resolution is XGA. In the image information area, the shooting date and time, shooting conditions such as on / off of a flash (not shown), a password for releasing the reproduction protection, and the like are written, and in the compressed data area, compressed original image data (photographed image data) Is stored.

In the thumbnail image data area, thumbnail image data is recorded in the same manner as described above. Specifically, following “SOI”, a quantization table data area,
A parameter area for the frame, a Huffman coding table data area, and a parameter area for the component are formed. At the beginning of each area, the corresponding markers “DQT”, “SOF”, “DHT” and “SO
After the parameter area relating to the component, compressed thumbnail data is stored, and finally, “EOI” is added.

A plurality of image files having such a file structure are recorded on the memory card 46. When the mode setting switch 46 is set to the reproduction side, the CPU 28
Processes the flowcharts shown in FIGS. First, in step S1, it is determined whether the current playback mode is the original mode or the thumbnail mode. Thumbnail on /
If the mode setting switch 46 is set to the reproduction side while the off switch 48 is in the off state, the CPU 28 determines "NO" in step S1, that is, the original mode.
In step S3, the latest image file recorded on the memory card 46 is stored in the work area 24 of the DRAM 24.
Copy to b. Next, in step S4, the work area 2
4b, a marker “DHT” corresponding to the original image data is detected from the image file copied to
At 5, it is determined whether the value of "DHT" is FFC4. If "YES" here, it is determined that the image file in the work area 24b is not protected from reproduction, and the process proceeds to step S37. If "NO", the image file in the work area 24b is protected from reproduction. The process proceeds to step S7.

After each marker shown in FIG. 2, size data of the corresponding area is recorded, and
In step 4, the position of the marker "DHT" is detected based on the size data. In step S7, the character generator 38 and the switch SW1 are driven to change the "Please enter password" character shown in FIG.
Display on CD34. When the operator operates the numeric keypad 50 to input a password and then presses the enter key 52, the CPU 28 determines "YES" in step S9,
In step S15, it is determined whether the password is correct. Specifically, the password written in the image information area is compared with the password input in step S9,
Determine whether the two match. If "NO" here, the CPU 28 displays the character "password is wrong" shown in FIG. 8 on the LCD 34 in step S17, and returns to step S9. If the password is correctly input, CPU 28 advances the process to step S19.

If the operator operates the update button 44 instead of the numeric keypad 50, the CPU 28 determines "YES" in a step S11, and copies the next image file from the memory card 46 to the work area 24b in a step S13. It returns to S4. Therefore, an operator who does not know the password can operate the update button 44 to reproduce only an image file that is not protected from being reproduced.

In step S19, the work area 24b
The value of the marker “DHT” recorded in the image file and corresponding to the original image data is changed from FF99 to FFC
Return to 4. That is, FF99 which is a value not satisfying the JPEG format is restored to FFC4 which is a value satisfying the JPEG format. Then, step S21
Decompresses the compressed original image data according to the JPEG format and converts the decompressed original image data to LC
Output to D34. Specifically, the compressed original image data stored in the compressed data area is subjected to decoding using a Huffman encoding table, the decoded data is subjected to inverse quantization using a quantization table, and the decoded data is subjected to inverse quantization. I
Perform DCT transformation. Further, the expanded original image data is converted into a second signal processing circuit 30 and a D / A converter 32.
And outputs it to the LCD 34. As a result, the original image is displayed on the LCD 34.

Subsequently, in step S23, the CPU 28 releases the character "reproduction protection shown in FIG.
"YES NO" is displayed on the LCD 34. If the operator selects "YES", the CPU 28 determines "YES" in a step S25, and in a step S27, the marker "D" recorded in the image file on the work area 24b.
HT "is returned to the FFC 4. At this time, not only the marker" DHT "corresponding to the original image data but also the value of the marker" DHT "corresponding to the thumbnail image data is returned to the FFC 4. Then, in step S29, the same image The password recorded in the image information area of the file is deleted, and in step S31, the image file subjected to such processing is overwritten on the same image file on the memory card 46. As a result, the reproduction protection of the image file is released. Is done.

When the update button 44 is pressed by the operator, the CPU 28 determines "YES" in a step S33, and copies the next image file from the memory card 46 to the work area 24b in a step S35. And
It returns to step S4. If the operator selects "NO" for the guidance display shown in FIG. 9, the CPU 28 proceeds directly from step S25 to step S33.

As described above, an image file protected for reproduction is reproduced only when a correct password is input. Further, the release of the reproduction protection is notified, and if the operator desires to release, the marker “DH” is displayed.
T "is restored and the password is erased. That is, if playback protection is set,
This protection is released only when a correct password is input. However, when the operator selects "YES" for the guidance shown in FIG. 9, the reproduction protection is always released.

When an unprotected image file is copied to the work area 24b, the CPU
In step S5, "YES" is determined in step S5,
Proceed to 37. In step S37, the above-described step S2
The original image data is reproduced in the same manner as in 1. CP
Next, U28 changes the character "reproduction protect? YES NO" shown in FIG.
Display on CD34. On the other hand, the operator responds "YE
If "S" is selected, the CPU 28 determines in step S41 that "Y"
ES ”, and in step S43, is the character“ thumbnail image shown in FIG. 11 also protected for reproduction? "YES NO" is displayed on the LCD 34.

When the operator selects "YES", C
PU28 proceeds from step S45 to step S49,
The values of both the marker “DHT” corresponding to the original image data and the marker “DHT” corresponding to the thumbnail image data are changed from FFC4 to FF99, and step S
Go to 51. On the other hand, if the operator selects "NO" for the guidance display shown in step S11, the CPU 28 proceeds to step S47 and changes only the marker "DHT" corresponding to the thumbnail image data from FFC4 to FF99.

When the marker "DHT" of the desired image data is rewritten, the CPU 28 proceeds to step S51 in FIG.
Is displayed on the LCD 34. When the operator operates the numeric keypad 50 and the enter key 52 to set a password,
The PU 28 determines “YES” in the step S53, and writes the password in the image information area of the image file stored in the work area 24b in a step S55.
Thereafter, in step S57, the image file in which the password is written is overwritten on the same image file on the memory card 46.

When "NO" is selected for the display shown in FIG. 11, or when the process of step S57 is completed, the CPU 28 proceeds to step S59 to determine whether or not the update button 44 has been pressed. If "YES" here, the next image file is copied from the memory card 46 to the work area 24b in a step S61, and the process returns to the step S4.

As described above, when an image file that is not protected by reproduction is reproduced, the operator can set an arbitrary password to apply reproduction protection. Further, both the original image data and the thumbnail image data or only the thumbnail image data can be protected by reproduction according to the operator's request.

When the operator sets the thumbnail mode with the thumbnail on / off switch 48 and switches the mode setting switch 46 to the reproduction side, the CPU 28 proceeds from step S1 to S63. In step S63, the count value N of the counter 28a is set to "1", and then in step S65, the corresponding image file is copied from the memory card 46 to the work area 24b. Subsequently, in step S67, a marker "DHT" corresponding to the thumbnail image data is detected, and in step S68, it is determined whether or not the value of this marker is FFC4. Here "YES"
If so, it is determined that the thumbnail image data of this image file is not protected from reproduction, and the thumbnail image data is reproduced in step S69 in the same manner as in step S21. On the other hand, if “NO” in the step S68, it is determined that the thumbnail image data of the image file is protected from reproduction, and the step S71 is performed.
To display the key mark on the LCD 34.

After completing the processing in step S69 or S71, the CPU 28 increments the count value N in step S73, and determines whether or not the count value N> 9 in step S75. If "NO" here, the process returns to the step S65 and the same processing as described above is repeated, but the "YE
If S ", the process is terminated. As a result of such a process being executed in the thumbnail mode, six thumbnail images and three key marks are displayed on the LCD 34 as shown in FIG. Then, N = 2,6
The reproduction protection is applied to the thumbnail image data of the image files corresponding to the items 7 and 7.

According to this embodiment, the marker "DHT" of the image file constructed according to the JPEG format is used.
Is rewritten, it is not possible to reproduce an image file in which the marker “DHT” is different from the predetermined value even by general-purpose software compatible with JPEG. That is,
Even when the memory card 46 is accessed by general-purpose software, reproduction of image data can be prevented.

By installing the programs in the flowcharts shown in FIGS. 3 to 6 on a personal computer, the image files recorded on the memory card can be reproduced on the personal computer. In this embodiment, the reproduction protection is set or released at the time of reproduction. However, the setting of the reproduction protection may be guided at the time of shooting, and the protection may be applied if desired. In this embodiment, the reproduction protection is applied to both the original image data and the thumbnail image data or only the thumbnail image data. However, the reproduction protection may be applied only to the original image data according to the operator's request. Further, in this embodiment, the content of the marker "DHT" is rewritten when the reproduction protection is applied, but "DQT",
The contents of “SOF” or “SOS” may be rewritten.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is an illustrative view showing a structure of an image file;

FIG. 3 is a flowchart showing a part of the operation of the embodiment in FIG. 1;

FIG. 4 is a flowchart showing another portion of the operation of the embodiment in FIG. 1;

FIG. 5 is a flowchart showing another portion of the operation of the embodiment in FIG. 1;

FIG. 6 is a flowchart showing yet another portion of the operation of the embodiment in FIG. 1;

FIG. 7 is an illustrative view showing one portion of an operation of the embodiment in FIG. 1;

FIG. 8 is an illustrative view showing another portion of the operation of the embodiment in FIG. 1;

FIG. 9 is an illustrative view showing another portion of the operation of the embodiment in FIG. 1;

FIG. 10 is an illustrative view showing yet another portion of the operation of the embodiment in FIG. 1;

FIG. 11 is an illustrative view showing another portion of the operation of the embodiment in FIG. 1;

FIG. 12 is an illustrative view showing another portion of the operation of the embodiment in FIG. 1;

FIG. 13 is an illustrative view showing one example of a thumbnail image;

[Explanation of symbols]

 10 Digital camera 24 DRAM 28 CPU 46 Memory card 50 Numeric keypad

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/76-5/907 H04N 5/225-5/243

Claims (8)

(57) [Claims] 1. A digital camera for recording, on a recording medium, an image file containing photographed image data and management information of the image data, a reproduction prohibition instruction unit for instructing reproduction inhibition of the image file, and a reproduction inhibition instruction. Changing means for changing the content of the management information based on the information, setting means for setting a password, and writing means for writing the set password to the image file, wherein the image data is compressed in JPEG format. includes br /> original casing image data and thumbnail image data, wherein the management information corresponding to the original image data Ha
A first marker of the Huffman encoding table and a second marker of the Huffman encoding table corresponding to the thumbnail image data .
A digital camera including a marker , wherein the changing means includes at least content changing means for changing the content of the first marker . 2. An internal memory, copy means for copying the image file from the recording medium to the internal memory, and overwriting means for overwriting the image file copied to the internal memory on the recording medium. Item 1. The digital camera according to Item 1. 3. The method according to claim 1, wherein the changing means further includes first activating means for activating the copying means in response to the reproduction prohibition instruction, and the contents changing means changes the contents on the internal memory. The writing means includes password writing means for writing the password in the image file on the internal memory, and second activation means for activating the overwriting means after the writing of the password is completed. 2. The digital camera according to item 2. 4. The original playback instruction means for instructing a reproduction of the original image data, the third activating means for activating said copying means in response to the reproduction instruction of the original image data, the on the internal memory first first detecting means for detecting a marker, reconstructing the request means for requesting input of the password in response to the contents of the first marker, the contents of the first marker on the internal memory when the correct the password is entered First restoring means, and the first marker restored by the first restoring means.
A first method of reproducing the original image data based on
The digital camera according to claim 2, further comprising a reproducing unit. 5. The thumbnail reproduction instruction means for instructing reproduction of the thumbnail image data, the fourth activating means for activating said copying means in response to the reproduction instruction of the thumbnail image data, wherein on the internal memory first 5. The apparatus according to claim 2, further comprising a second detection unit that detects two markers , and a second reproduction unit that reproduces one of the thumbnail image data and the predetermined character data according to the content of the second marker. 6. The digital camera according to any one of the above. 6. A release instructing unit for instructing release of the reproduction prohibition, a fifth activation unit for activating the copy unit in response to the release instruction, the first marker and the first marker on the internal memory . 2 mer
Third detection means for detecting the mosquitoes, the first marker on the internal memory and the second mer
Second restoring means for restoring the contents of Ca, further comprising a sixth activating means for activating said overwriting means from the erase is complete erase means, and said password deletes the password on the internal memory,
The digital camera according to claim 2. 7. The photographed image data and the image data
Record an image file containing data management information on a recording medium.
Prohibition instructing the digital camera to prohibit reproduction of the image file.
And changing the content of the management information based on the reproduction prohibition instruction.
Further changing means, setting means for setting a password, and set the
Writing means for writing a password in the image file
Wherein the image data is the original image data and thumbnail
And the management information includes an image corresponding to the original image data.
For the original management information and the thumbnail image data,
Corresponding thumbnail management information, wherein the changing means includes the original management information and the thumbnail.
A means for changing both contents of nail management information
A digital camera , comprising: 8. A digital camera for recording on a recording medium an image file containing photographed image data and management information of the image data, wherein reproduction inhibition instruction means for instructing reproduction inhibition of the image file; Changing means for changing the content of the management information based on: setting means for setting a password; writing means for writing the set password to the image file; internal memory; and transferring the image file from the recording medium to the internal memory. Copying means for copying, and overwriting means for overwriting the image file copied to the internal memory on the recording medium, wherein the changing means activates the copying means in response to the reproduction prohibition instruction. (1) activating means and a pipe for changing the content of the management information on the internal memory Password writing means for writing the password in the image file on the internal memory, and a second activation for activating the overwriting means after the writing of the password is completed. Means, the image data includes original image data, and thumbnail image data, the management information includes original management information corresponding to the original image data, and thumbnail management information corresponding to the thumbnail image data, The digital camera according to claim 1, wherein the management information change unit further includes a content change unit that changes the contents of both the original management information and the thumbnail management information.