JP3752931B2 - Digital camera and image data processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital camera that converts light from a subject to be photographed into a digital signal, compresses and records the image, and a processing method for compressing image data in the digital camera.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known a digital camera that converts light into an electric signal by an imaging unit such as a CCD (Charge Coupled Device), converts the electric signal into digital data, and records the data on a recording medium such as a flash memory. Using a digital camera, you can easily save image data and perform various processing by using a personal computer, and print images without developing the film by outputting the image data to a printer. it can. In recent years, it has become possible to print high-quality photographs that are almost indistinguishable from silver-salt photographs due to improvements in the printing quality of printers.
[0003]
In the digital camera as described above, since the capacity of the recording medium is limited, for example, a lossy compression method conforming to the JPEG (Joint Photographic coding Experts Group) standard (hereinafter referred to as “lossy compression method conforming to the JPEG standard”). "JPEG") is used to compress the image data to reduce the capacity, and to increase the number of shots that can be recorded on one recording medium.
[0004]
The basic configuration of the JPEG algorithm is to divide the original image data into 8 × 8 pixel blocks, perform DCT operation for each block, and independently quantize the DCT coefficients obtained by DCT operation with DC and AC components. To do. The quantization table used for quantization is a factor that determines the file size of the encoded image data and the reproduction image quality of the encoded image data. For example, if the quantization characteristic value is increased by increasing the scale factor for specific image data, the compression rate increases and the file size at the time of recording can be reduced, while the degradation of the image quality of the reproduced image is significant. Become.
[0005]
In addition, since the relationship between the quantization characteristic value, the file size of the encoded image data, and the reproduction image quality changes depending on the image characteristic of the image data before compression, if the image data is different, the same quantization characteristic value is used. However, the file size and playback image quality at the time of recording are different. For example, image data with a lot of high-frequency components that make up the contour of the image has a noticeable deterioration in playback quality when the quantization characteristic value is increased, while image data with few high-frequency components has a larger quantization characteristic value. Sometimes there is little degradation of playback image quality.
[0006]
[Problems to be solved by the invention]
However, according to the conventional digital camera, the scale factor that determines the quantization characteristic value based on the reference quantization table is a fixed value or is set before shooting. The quantization characteristic value could not be changed according to the above. Therefore, for image data with little degradation in playback image quality when the quantization characteristic value is increased, the quantization characteristic value is appropriately changed after shooting, such as increasing the compression characteristic value and increasing the compression rate to record on the recording medium. As a result, the recording medium cannot be used efficiently.
[0007]
The present invention has been made to solve such a problem, and provides a digital camera and an image data processing method capable of changing a quantization characteristic value according to the characteristic of image data before compression. With the goal.
[0008]
[Means for Solving the Problems]
According to the digital camera of the first aspect of the present invention, since the image characteristic output means for displaying the file size of the encoded image data on the basis of the image data in the storage means is provided, the operator can obtain the image data when the image data is compressed. You can know the file size after shooting and before compression. When displaying the file size, for example, a copy of the image data is actually compressed with software, and the compressed file size is displayed on the back display of the digital camera, or the file size is displayed using the function of an LSI chip dedicated to compression. Can be displayed. Further, when displaying the file size, not only the number displayed on the display but also various methods such as a graph displayed on the display or a display based on the number of LEDs to be lit can be adopted.
[0009]
In addition, since a means for changing a parameter for determining the quantization characteristic value used for compression based on the quantization table is provided, the operator can change the parameter with reference to the displayed file size and obtain it by photographing. The quantization characteristic value can be changed according to the characteristic of the obtained image data. The compression recording means generates the encoded image data by compressing the image data in the storage means using the quantization characteristic value determined by the parameter thus changed, and stores it in the recording medium. Will be operated on.
[0010]
According to the digital camera of the first aspect of the present invention, the image characteristic output means is a file of encoded image data generated when the image data in the storage means is compressed using a quantization characteristic value determined by a predetermined parameter. Inquires the compression recording means for the size, and displays the correlation information between the parameter and the file size of the encoded image data for the image data in the storage means, so that the operator compresses to the desired file size by increasing or decreasing the parameter. You can know what you can do. That is, the operator can efficiently operate the recording medium by considering the file size and the reproduction image quality considering that the reproduction image quality varies depending on the parameters.
[0011]
The value returned by the compression recording means when receiving an inquiry from the image characteristic output means is calculated by using the quantization characteristic value determined by the compression recording means according to a predetermined parameter. Use it to calculate the file size and analyze the result to output continuous correlation information, or output how much the compression rate will be when compressed using one specific parameter can do. For example, by determining the default parameters and displaying the compression rate when compression is performed using the default parameters, the operator has a high or low compression effect on the image characteristics of the captured image data. Can know. When the compression rate is displayed in this way, when an object that does not like image quality degradation is photographed, the operator changes the parameter so that the quantization characteristic value becomes small when the image data has a high compression effect. Thus, the recording medium can be operated efficiently. The compression rate is the ratio between the file size before compression and the file size after compression.
[0012]
According to the digital camera of the second aspect of the present invention, since the image characteristic output means displays the correlation information in a graph, the operator can easily understand the correlation between the parameter and the file size after compression.
[0013]
According to a third aspect of the present invention, there is provided decoded image confirmation means for decoding and displaying the encoded image data obtained by compressing the image data in the storage means using the quantization characteristic value determined by the changed parameter. . Therefore, the operator can input the parameters after knowing what reproduction image quality can be obtained by the parameters. For example, when a specific key is pressed in a state where the correlation information between the parameter and the compressed file size is displayed in a graph together with the currently set parameter, the encoded image is compressed using the currently set parameter. When data is generated, the encoded image data is decoded, and a reproduced image is displayed on the rear display of the digital camera, the operator can easily set parameters capable of obtaining a desired reproduced image quality.
[0014]
According to the image data processing method of the fourth aspect of the present invention, the image data processing method includes the image characteristic output step of displaying the file size of the encoded image data based on the image data in the storage means. You can know the file size after shooting and before compression. In addition, since it includes an input reception step for accepting a parameter change for determining a quantization characteristic value to be used for compression based on the quantization table, the operator changes the parameter with reference to the displayed file size, shoots The quantization characteristic value can be changed according to the characteristics of the obtained image data. In the compression recording step, the image data in the storage means is compressed using the quantization characteristic value determined by the parameter thus changed, and the encoded image data is generated and stored in the recording medium. Will be operated on.
[0015]
According to the image data processing method of the present invention, it is generated when the image data in the storage means is compressed using the quantization characteristic value determined by the predetermined parameter in the quantization table in the image characteristic output step. The file size of the encoded image data is calculated, and correlation information between the parameter and the file size of the encoded image data is displayed for the image data in the storage means. For this reason, the operator can know how much the parameter can be compressed to a desired file size by increasing or decreasing the parameter. That is, the operator can efficiently operate the recording medium by considering the file size and the reproduction image quality considering that the reproduction image quality varies depending on the parameters.
[0016]
According to the image data processing method of the fifth aspect of the present invention, since the correlation information is displayed in a graph in the image characteristic output step, the operator can easily understand the correlation between the parameter and the file size after compression.
[0017]
According to the image data processing method of the sixth aspect of the present invention, the encoded image data obtained by compressing the image data in the storage means using the quantization characteristic value determined by the parameter changed in the input receiving step is decoded and displayed. Since the decoding image confirmation step is included, the operator can input parameters after knowing what reproduction image quality can be obtained by the parameters.
[0018]
According to the recording medium of the seventh aspect of the present invention, since the image characteristic output procedure for displaying the file size of the encoded image data is executed based on the image data in the storage means, the operator compresses the image data. You can know the file size at the time before shooting and before compression. In addition, since an input reception procedure for receiving a change in parameter for determining a quantization characteristic value used for compression based on the quantization table is executed, the operator changes the parameter with reference to the displayed file size, and performs shooting. The quantization characteristic value can be changed according to the characteristics of the image data obtained in this way. When the recording procedure is executed, the image data stored in the storage means is compressed using the quantization characteristic value determined by the parameter thus changed, and the encoded image data is generated and stored in the recording medium. Will be operated efficiently. When installing the program in the digital camera, for example, the program is stored in a flash memory card or the like, and the installer stored in the flash memory card is executed by the digital camera and installed in the ROM, or the digital camera is installed in the personal computer. Can be installed in the ROM of a digital camera from a personal computer.
[0019]
According to the recording medium of claim 7 of the present invention, in the image characteristic output procedure, the encoding generated when the image data in the storage means is compressed using the quantization characteristic value determined by the predetermined parameter in the quantization table. The file size of the image data is calculated, and the correlation information between the parameter and the file size of the encoded image data is displayed for the image data in the storage means. For this reason, the operator can know how much the parameter can be compressed to a desired file size by increasing or decreasing the parameter. That is, the operator can efficiently operate the recording medium by considering the file size and the reproduction image quality considering that the reproduction image quality varies depending on the parameters.
[0020]
According to the recording medium of the eighth aspect of the present invention, since the correlation information is displayed in a graph in the image characteristic output procedure, the operator can easily understand the correlation between the parameter and the file size after compression.
[0021]
According to the recording medium of the ninth aspect of the present invention, the decoded image for decoding and displaying the encoded image data obtained by compressing the image data in the storage means using the quantization characteristic value determined by the parameter changed in the input reception procedure. Since the confirmation procedure is executed, the operator can input parameters after knowing what reproduction image quality can be obtained by the parameters.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example showing an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a block diagram for explaining the configuration of the digital camera 1 that records image data using an image data processing method according to an embodiment of the present invention. The digital camera 1 includes an optical system 20, a CCD 30, an A / D converter 40, a RAM (Random Access Memory) 50 that temporarily stores image data, a compression dedicated LSI 60 that executes JPEG compression processing, and a detachable flash memory 80. A memory card interface 70 for recording image data, a display device 100, a control unit 90 for controlling these devices, an input device 110 for requesting processing from the operator to the control unit 90, and the like.
[0023]
The optical system 20 is provided with a condenser lens 21, a diaphragm 121 for adjusting the amount of light, and an automatic focusing device and an automatic exposure device (not shown).
In the CCD 30, imaging elements having any of complementary colors filters of Cy (Cyan), Mg (Magenta), Ye (Yellow), and G (Green) are arranged in a matrix as shown in FIG. 4. Three colors of Cy, Mg, and Ye may be used as complementary color filters. A CCD having primary color filters of R (Red), G (Green), and B (Blue) may be used.
[0024]
The A / D converter 40 is a device that converts an analog signal output from the CCD 30 into a digital signal and outputs the digital signal to the RAM 50.
A DRAM (Dynamic RAM) having a self-refresh function is used for the RAM 50 as a storage device.
[0025]
The compression-dedicated LSI 60 is a dedicated chip for JPEG compression, and can calculate the data size after JPEG compression by calculation, and has a terminal for outputting the calculation result to the CPU. The configuration of the compression dedicated LSI 60 is shown in FIG. Reference numeral 61 denotes a DCT converter that executes two-dimensional DCT (Discrete Cosine Transform) in units of 8 × 8 pixel blocks on input image data. A quantizer 62 linearly quantizes the output of the DCT converter 61. Reference numeral 66 denotes a standard quantization table composed of default quantization characteristic values. The standard quantization table 66 is connected to the quantizer 62 via the multiplier 65. A scale factor register 12 stores a scale factor input to the multiplier 65. The scale factor stored in the scale factor register 12 corresponds to the parameters described in the claims, and is changed by the control unit 90 when the input device 110 is operated. 63 is a Huffman encoder for Huffman encoding the output of the quantizer 62. Reference numeral 67 denotes an encoding table connected to the Huffman encoder 63 and referred to when encoding the output of the quantizer 62.
[0026]
The memory card interface 70 is a device that records the encoded image data output from the compression dedicated LSI 60 in the flash memory 80. In this embodiment, the compression dedicated LSI 60 and the memory card interface 70 constitute the compression recording means described in the claims.
[0027]
The flash memory 80 is a rewritable recording medium that can retain the recorded contents without being energized, and may be built in the digital camera 1. By using, for example, a memory card conforming to the PCMCIA standard or a memory card that can be attached to a PCMCIA card adapter as the flash memory 80, the contents of the flash memory 16 can be directly read and written by a personal computer having a PCMCIA card slot. The flash memory 80 constitutes a recording medium described in the claims.
[0028]
The control unit 90 includes a ROM in which programs for performing various controls of the digital camera 1 are recorded, a CPU that executes the programs, and the like, and controls other devices provided in the digital camera 1. In addition to performing all the control by one control unit 90, a plurality of control units may be provided. In this embodiment, the control unit 90 and the display device 100 constitute the image characteristic output means described in the claims.
[0029]
As shown in FIGS. 5 and 6, the input device 110 includes various switches 111 to 116 provided in the housing of the digital camera 1, a processing device (not shown), and the like. When the switches 111 to 116 are operated, a specific process is requested to the control unit 90.
[0030]
The display device 100 includes a drive circuit (not shown), an LCD 101 provided on the back surface of the housing of the digital camera 1, and the like. An image is displayed on the LCD 101 based on a drawing command transmitted from the control unit 90.
[0031]
Hereinafter, the operation of the digital camera 1 will be described.
When the mode switching dial 112 is in the “View” position, shooting is performed using the LCD 17 as a viewfinder as follows.
[0032]
(Select shooting mode)
When the select key 116 is pressed, the menu display mode is entered and a guidance screen is displayed on the LCD 101. By operating the first arrow key 114 and the second arrow key 115, a scale factor is set after shooting and before compression. You can choose whether or not. Such a function is such that the lower-level program executed by the control unit 90 when the shutter button 112 is pressed differs depending on the shooting mode selected by the first arrow key 114 and the second arrow key 115. This can be realized by designing a higher-level program. In the following description, it is assumed that a shooting mode for setting a scale factor is selected after compression after shooting.
[0033]
(Subject LCD display)
The subject image captured by the optical system 20 is formed on the CCD 30 by the optical system 20. The signal output for each color photoelectrically converted by the CCD 30 is converted into a digital signal by the A / D converter 40, and this digital signal output is input to the display device 100 together with a drawing command by the control unit 90. As a result, the display device 100 displays the subject as a moving image on the LCD 101.
[0034]
(Subject shooting)
The exposure at the time of shooting is changed by controlling the automatic exposure device of the optical system 20 and the shutter speed, that is, the accumulation time of the CCD 30, based on the data output from the CCD 30. As the shutter of the digital camera 1, a shutter that physically blocks light from the outside to the CCD 30, an electronic shutter of the CCD 30, or both can be used.
[0035]
When the user presses the shutter button 111 of the digital camera 1 halfway, the control unit 90 controls the autofocus device and the autoexposure device to set appropriate exposure and focus on the image recognized by the CCD 30, and the shutter button 111 is halfway. Exposure and focus are fixed during pressing.
When the user fully presses the shutter button 111, image recording is started according to the procedure shown in FIG.
[0036]
(Data capture by CCD)
In step S101, all charges accumulated in the CCD 30 are once discharged, and a subject image is formed on the CCD 30 by the optical system 20, whereby the light is converted into charges corresponding to the amount of light in the CCD 30. The electrical signal output from the CCD 30 is converted into a digital signal by the A / D converter 40. Digital data output from the A / D converter 40 is directly transferred to the RAM 50 by DMA (Direct Memory Access) without going through the control unit 90.
[0037]
(Color completion and color space conversion)
The data stored in the RAM 50 indicates the luminance of the light transmitted through the filter as shown in FIG. 4, and has only information corresponding to one color per pixel. For this reason, in step S102, color interpolation processing is performed to convert the data stored in the RAM 50 into image data of, for example, 1280 × 960 pixels.
[0038]
In this embodiment, since image data is compressed by JPEG and recorded, color space conversion for obtaining information necessary for compression using color information around the pixel of interest and the following approximate expression is performed.
Luminance component Y component of image:
Y = {G + Mg + Ye + Cy} × 1/4 = ¼ {2B + 3G + 2R}
Chroma (color difference) component:
RY = {(Mg + Ye)-(G + Cy)} = {2R-G}
B−Y = {(Mg + Cy) − (G + Ye)} = {2B−G}
[0039]
Of the luminance signal Y and the color difference signal (UV) calculated in this way, the luminance component is calculated as 1280 × 960 pixels, and the color difference component is calculated as a pixel in the horizontal direction in units of two pixels to be 640 × 960 pixels. Calculate as In this method, information of color components is partially arithmetically averaged by a so-called JPEG 4: 2: 2 method to compress data. The above processing is performed by a program executed by the control unit 90. When image data including Y data of 1280 × 960 pixels and U and V data of 640 × 960 pixels is stored in the RAM 50, the control unit 90 Control is transferred to a program for displaying image characteristics on the LCD 101.
[0040]
(Display image characteristics)
When control is transferred to a program for displaying image characteristics, the image characteristics are displayed on the LCD 101 as follows.
[0041]
The control unit 90 stores the default scale factor in the scale factor register 64 of the compression dedicated LSI 60 and then inputs image data from the RAM 50 to the compression dedicated LSI 60. The compression-dedicated LSI 60 uses the function of calculating the file size of the encoded image data generated when JPEG compression processing is performed on the input image, and sends the file size of the encoded image data to the control unit 90. Notice.
[0042]
When the control unit 90 receives the file size notification from the compression-only LSI 60, the control unit 90 approximates the continuous correlation between an arbitrary scale factor and the file size of the encoded image data from the default scale factor and the received file size. An equation is obtained, data for displaying a graph as shown in FIG. 7 on the LCD 101 is calculated, and a drawing command is issued to the display device 100 based on this data.
[0043]
In addition, by executing the process for notifying the file size to the compression-dedicated LSI 60 a plurality of times and changing the scale factor for each process, an arbitrary scale factor and encoding can be performed from the correlation between the plurality of scale factors and the plurality of file sizes. An approximate expression indicating a continuous correlation with the file size of the image data may be obtained.
[0044]
FIG. 7 shows a graph displayed on the LCD 101 based on the drawing command issued from the control unit 90 as described above. In each of the graphs (A) to (E), the horizontal axis indicates the scale factor, and the vertical axis indicates the file size of the encoded image data. In order to make it easier for the operator to understand the correlation between the scale factor and file size, the horizontal axis displays “clean” and “rough” characters, and the vertical axis displays “large” and “small” characters. The The triangle displayed on the horizontal axis indicates the size of the scale factor stored in the scale factor register 64 according to its position. A dotted line is displayed from the triangle in the vertical axis direction. Furthermore, a dotted line is displayed in the horizontal axis direction from the intersection of the dotted line and the graph. These dotted lines move in parallel with the movement of the triangle, and the intersection of the dotted line in the horizontal axis direction and the vertical axis indicates the file size of the encoded image data.
[0045]
In the graph shown in FIG. 7A, the relationship between the scale factor and the file size of the encoded image data indicates standard image characteristics.
[0046]
When the photographed subject has few contour elements, the image data contains less information with high spatial frequency and less information is deleted by compression, so the curve is closer to the upper left of the coordinate plane as shown in FIG. be painted. When the default scale factor is applied to image data having such image characteristics, the file size after compression is larger than that in the standard case, and there is little deterioration in the reproduction image quality. Recognized by the operator by the graphical display.
[0047]
If the photographed subject has many contour elements, the image data contains a lot of information with a high spatial frequency and a lot of information is deleted by compression. Therefore, as shown in FIG. Drawn in. When the default scale factor is applied to image data having such image characteristics, the file size after compression is smaller than that in the standard case, and the deterioration in reproduction image quality is severe. Recognized by the operator by the graphical display.
[0048]
(Change of scale factor)
When the graph shown in FIG. 7 is displayed on the LCD 101, the scale factor used for compression can be changed by operating the first arrow key 114 and the second arrow key 115. The processing for changing the scale factor used for compression is performed by receiving a notification from the input device 110 when the program for displaying image characteristics is operated by the first arrow key 114 or the second arrow key 115, and This is realized by recognizing that a change request has occurred and rewriting the value of the scale factor register 64 in accordance with the operation of the first arrow key 114 or the second arrow key 115. Further, when a scale factor change request is generated, the control unit 90 issues a drawing command to the display device 100 in accordance with the operation of the first arrow key 114 or the second arrow key 115, and FIG. As shown in FIG. 7E, the triangle displayed on the graph, the dotted line in the vertical axis direction, and the dotted line in the horizontal axis direction are moved. The operator moves the triangle on the horizontal axis, and the dotted line in the vertical axis and the dotted line in the horizontal axis move in parallel to recognize the file size when compressed using the scale factor specified by the operator. Can be guessed.
[0049]
When the select key 116 is operated while the graph is displayed on the LCD 101, a copy of the image data is compressed by applying the scale factor selected at that time, and further decrypted. A function of displaying data on the LCD 101 can also be realized. When such a function is provided, the operator can determine the scale factor while reconciling the reproduction image quality and the file size while actually confirming the reproduction image quality. Such a function is realized by a program for decoding compressed image data. When realizing such a function, the LCD 101 and the CPU that executes a program for decoding the compressed image data constitute the decoded image confirmation means described in the claims.
[0050]
(Compression process)
When the select key 116 is operated while the graph is displayed on the LCD 101, compression processing is executed by the compression-dedicated LSI.
[0051]
The compression process is executed as follows.
A digital signal as image data input to the DCT converter 61 is a small image block (N × N) composed of predetermined pixels (N pixels) set by the DCT converter 61 from the orthogonal transformation efficiency in both the horizontal and vertical directions. It is divided into. At this time, the magnitude of N is set to 8 or 16 from the conversion efficiency of DCT. The reason for this is that the conversion efficiency improves as N increases, while the improvement trend shows a saturation tendency and the scale of the apparatus increases as the calculation scale increases. In this embodiment, N is set to 8. Two-dimensional DCT is performed for each small block composed of 8 × 8 pixels, and a DCT coefficient is obtained.
[0052]
The obtained DCT coefficient output is linearly quantized by the quantizer 62 using the standard quantization table 66 and the scale factor to obtain a quantized coefficient. The quantization characteristic value of the standard quantization table 66 is multiplied by the scale factor stored in the scale factor register 64 and the accumulator 65, and the product is directly used for linear quantization. Therefore, when the scale factor is changed, the quantization characteristic value directly used for linear quantization varies.
[0053]
The quantized coefficient output is Huffman encoded using the encoding table 63. The Huffman-encoded encoded image data is transferred to the memory card interface 70, and the output is recorded on the memory card 80.
The series of compression processes can be performed by the control unit 90 in software.
The operation of the digital camera 1 has been described above.
[0054]
According to the digital camera 1, before the image data stored in the RAM 50 is compressed, the correlation information between the compressed file size and the scale factor is displayed on the LCD 101, and the quantization characteristic value is changed by changing the scale factor. Therefore, the compression rate can be changed according to the characteristics of the image data obtained by photographing. Since the encoded image data to be compressed using the quantization table to which the changed quantization characteristic value is applied is stored in the memory card, the storage area of the memory card can be efficiently used. .
[Brief description of the drawings]
FIG. 1 is a flowchart showing a procedure for recording image data by a digital camera according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a digital camera according to an embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a compression dedicated LSI according to an embodiment of the present invention.
FIG. 4 is a schematic diagram showing a filter provided in a CCD according to an embodiment of the present invention.
FIG. 5 is a plan view showing a digital camera according to an embodiment of the present invention.
FIG. 6 is a rear view showing a digital camera according to an embodiment of the present invention.
FIG. 7 is a schematic diagram showing a display state of image characteristics in an embodiment of the present invention.
[Explanation of symbols]
1 Digital camera
50 RAM (storage means)
60 Compression dedicated LSI (compression recording means)
70 Memory card interface (compression recording means)
80 Flash memory (recording medium)
90 control unit (image characteristic output means)
100 Display device (image characteristic output means)
110 Input device (input means)

Claims (9)

A digital camera that converts light into image data and stores it in a storage means, and stores encoded image data obtained by compressing the image data in the storage means using a quantization table in a recording medium;
Image characteristic output means for displaying the file size of the encoded image data based on the image data of the storage means;
Input means for receiving an operation of changing a parameter for determining a quantization characteristic value used for compression based on the quantization table;
Means for changing the parameter in response to an operation for changing the parameter;
Compression recording means for compressing the image data of the storage means using a quantization characteristic value determined by the parameter to generate encoded image data and storing it in the recording medium,
The image characteristic output means inquires of the compression recording means about the file size of the encoded image data generated when the image data of the storage means is compressed using a quantization characteristic value determined by the predetermined parameter, Displaying correlation information between the parameters and the file size of the encoded image data for the image data in the storage means;
A digital camera characterized by that.   2. The digital camera according to claim 1, wherein the image characteristic output means displays the correlation information in a graph.   3. A decoded image confirmation unit for decoding and displaying encoded image data obtained by compressing the image data of the storage unit using a quantization characteristic value determined by the changed parameter. Digital camera. This is an image data processing method used in a digital camera that converts light into image data and stores it in a storage means, and stores encoded image data obtained by compressing the image data in the storage means on a recording medium using a quantization table. An image characteristic output step for displaying a file size of the encoded image data based on the image data in the storage means, and a parameter change for determining a quantization characteristic value used for compression based on the quantization table. An input receiving step of receiving, and a compression recording step of compressing the image data of the storage means using a quantization characteristic value determined by the parameter to generate encoded image data and storing it in the recording medium,
In the image characteristic output step, the file size of the encoded image data generated when the image data of the storage unit is compressed using the quantization characteristic value determined by the predetermined parameter is calculated, and the image of the storage unit is calculated. Displaying correlation information between the parameter and the file size of the encoded image data for the data;
An image data processing method characterized by the above.   5. The image data processing method according to claim 4, wherein in the image characteristic output step, the correlation information is displayed in a graph.   And a decoded image confirmation step of decoding and displaying the encoded image data obtained by compressing the image data of the storage means using the quantization characteristic value determined by the parameter changed in the input receiving step. Item 6. The image data processing method according to Item 4 or 5. A program for causing a digital camera processing apparatus to store encoded image data obtained by converting light into image data and storing it in a storage means and compressing the image data stored in the storage means using a quantization table. An image characteristic output procedure for displaying a file size of the encoded image data based on the image data of the storage means, and a quantization characteristic value used for compression An input reception procedure for accepting a parameter change to be determined based on a table and a quantization characteristic value determined by the parameter to generate encoded image data by compressing the image data in the storage means and store it in the recording medium A compression recording procedure to be executed by a digital camera processing device,
In the image characteristic output procedure, a file size of encoded image data generated when the image data of the storage unit is compressed using a quantization characteristic value determined by the predetermined parameter is calculated, and the image of the storage unit is calculated. Displaying correlation information between the parameter and the file size of the encoded image data for the data;
The computer-readable recording medium which recorded the program characterized by the above-mentioned.   8. The computer-readable recording medium having a program recorded thereon according to claim 7, wherein the correlation information is displayed in a graph in the image characteristic output procedure.   A decoded image confirmation procedure for decoding and displaying encoded image data obtained by compressing the image data of the storage means using a quantization characteristic value determined by the parameter changed in the input reception procedure is provided. Item 9. A computer-readable recording medium on which the program according to Item 7 or 8 is recorded.

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