JP2965779B2 - Electronic still camera device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electronic still camera device for converting an optical image of a photographed subject into digital image data, performing compression processing and recording the digital image data on a recording medium.

[0002]

2. Description of the Related Art As is well known, in recent years, there has been developed an electronic photographic system for converting an optical image of a photographed subject into digital image data and displaying an image on a television receiver based on the digital image data. It has been developed and spread to the market. As one example of such an electrophotographic system, there is an electronic still camera device. This electronic still camera device includes semiconductor memory, magnetic tape,
A recording medium such as a disc is mounted on the camera body, and digital image data obtained by shooting is recorded.After shooting, the recording medium is removed from the camera body, mounted on a playback device, and connected to the playback device. A still image is displayed by the selected television receiver.

In such an electronic still camera device, since the amount of digital image data to be handled is enormous, it is necessary to record a large amount of digital image data in a limited capacity of a recording medium. The digital image data is subjected to a compression process. As this data compression means, ADCT technology is generally used. This is because the input data is divided into blocks of 8 × 8 pixels in the horizontal and vertical directions, two-dimensional DCT (Discrete Cosine Transform) operation processing is performed, then the data is quantized, and a block of the DC (direct current) component is compared with the previous block. The difference is obtained, and finally entropy coding is performed using a Huffman table to perform variable-length encoding.

Here, since the above ADCT process is basically a variable length coding process, it is usual that the compression code amount for one still image is not known until the process is completed.
Therefore, a code amount control process has been developed which extracts a feature (activity) of an image, calculates a coding parameter for each image based on the feature, and allocates bits to each image block. . By controlling the code amount in this way, for example, the compression ratio is reduced from 1/4 to 1
/ 16 can be selected, and the number of still images to be recorded on the recording medium is guaranteed. The compression ratio can be selected and set by the user.

FIG. 5 shows such a conventional electronic still camera device. That is, an optical image of a subject incident through the lens unit 11 is formed on a charge-coupled device (CCD) 12 and converted into an electric image signal. The image signal output from the CCD 12 is supplied to a signal processing circuit 13 where the image signal is subjected to a color separation process, and then an A / D (analog / digital) conversion circuit 1
At step 4, it is converted into digital image data. Then, the digital image data is supplied to the compression circuit 15 and subjected to the above-described DCT operation, quantization and encoding processing, and the data amount is compressed. In this case, code amount control is performed based on the compression ratio set by the user in the compression ratio setting operation unit 16, and the digital image data after compression is I / O
Recording medium 18 via F (interface) circuit 17
Will be recorded.

However, image data compression in a high-efficiency coding method such as the above-described ADCT process involves loss of image data. When the compression ratio is increased, the image quality is greatly deteriorated. The degree of deterioration greatly differs depending on the picture. For this reason, when the user selects and sets the compression ratio, there are cases where the deterioration of the image quality is noticeable at the compression ratio and cases where the number of recordings can be increased by increasing the compression ratio still more. There is a problem that it is difficult to select a compression ratio.

[0007]

As described above, in the conventional electronic still camera device, when the user selects and sets the compression ratio, the image quality deteriorates conspicuously. However, it is difficult to determine whether the compression rate can be increased, and it is difficult to set an appropriate compression ratio.

Accordingly, the present invention has been made in view of the above circumstances, and has as its object to provide an extremely good electronic still camera device which allows a user to easily select and set an appropriate compression ratio. .

[0009]

SUMMARY OF THE INVENTION The electronic still camera apparatus according to the present invention, taken by an optical image of a subject into digital image data, accompanied selectively set code amount control based on the compression rate It is intended to record data on a recording medium after performing data compression processing. And the compression ratio
Means for setting a compression ratio to be set ; calculating means for calculating the activity of the digital image data;
Provide a reference value that is related to the appropriate compression ratio for the activity.
Activity and reference value calculated based on the reference value of
Means for comparing data and data based on the comparison result.
Table showing that the compression ratio of the compression process can be increased
It is obtained by the so that a display means for performing shown.
Further, the electronic still camera device according to the present invention has the above-mentioned configuration.
Compression ratio setting means for setting a compression ratio in the object;
Calculation means for calculating the activity of digital image data
And the compression ratio appropriate for the activity of the image data.
Is provided based on this table.
Means for comparing selected activity with table values
And the compression ratio of the data compression process based on this comparison result.
Display that can be increased, decrease compression ratio
Display means for performing a display indicating that it is necessary to
That's what I did. Furthermore, the electronic device according to the present invention
The still camera device sets the compression ratio for the above objects.
Compression rate setting means to determine the
Calculating means for calculating the activity and the activity of the image data.
Provide a table showing the relationship between the compression ratio and the
Activities and tables calculated based on the table
Based on the result of the comparison.
To increase the compression ratio of the data compression process
The first display indicates that the compression rate is optimal, and the second display indicates that the compression rate is optimal.
Display, indicating that the compression ratio needs to be lowered
Display means for performing display.
You.

[0010]

According to the above arrangement, the activity of digital image data obtained by shooting is calculated, and the activity is selectively set for the calculated activity .
Compare the compression ratio and increase the compression ratio of the data compression process.
The display indicates that the
Indicates that it is necessary to lower the compression ratio.
Since the display shown is performed, the user can easily select and set an appropriate compression ratio.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1, the same parts as those in FIG. 5 are denoted by the same reference numerals. That is, in the process of performing compression processing of image data accompanied by code amount control based on the compression ratio set by the compression ratio setting operation unit 16 in the compression circuit 15, the image data is output from the A / D conversion circuit 14. By guiding the digital image data to the activity calculating circuit 19, the activity or the amount of information of the image data is calculated. The activity calculated by the activity calculating circuit 19 is used together with the compression ratio set by the compression ratio setting operation unit 16 in the comparison circuit 2.
0 is supplied.

In the comparison circuit 20, a table indicating the relationship between the activity of the image data and the optimum compression ratio for the activity is prepared in advance, and the activity calculation circuit 19 calculates the relationship based on this table. It is determined whether or not the compression ratio set for the activity is appropriate. If not, it is determined whether the compression ratio should be increased or decreased. Then, the determination result of the comparison circuit 20 is displayed on the display unit 21.
As shown in FIG. 2, the display unit 21 has three LEDs (light emitting diodes) below a viewfinder 22 of the camera.
Are arranged vertically.

As shown in FIG. 3A, these LEDs are colored green at the center and red at the top and bottom, and when the comparison circuit 20 determines that the relationship between the activity and the compression ratio is appropriate. In this display mode, only the center green LED is turned on and the other red LEDs are turned off. When the comparison circuit 20 determines that the compression ratio is low for the activity and the compression ratio can still be increased, as shown in FIG. To raise. Further, when the comparison circuit 20 determines that the activity has a high compression ratio and image quality deterioration is conspicuous, as shown in FIG. To instruct.

Therefore, according to the configuration of the above-described embodiment, the activity of the captured image data is calculated, and whether the compression rate selected and set for the calculated activity is appropriate or not is determined. Is determined, and if not appropriate, it is determined whether to increase or decrease the compression ratio, and the determination result is displayed on the display unit 21 provided in the viewfinder 22. The compression ratio can be easily selected and set. In particular, increase not only compression ratio but also compression ratio
It also displays what you can do, so you can record
It is possible to effectively use the capacity of the medium. Also,
An appropriate display time of the display unit 21 is one stroke period of the release switch of the camera.

The display by the display unit 21 is provided as an index for allowing the user to easily select and set an appropriate compression ratio. For example, even if an instruction to lower the compression ratio is issued, the display unit 21 is not used. It is possible for the user to take a picture with knowledge of the image quality degradation without following the instruction.

FIG. 4A shows another example of the display section 21. That is, of the three LEDs arranged vertically and colored green at the center and red at the top and bottom, the upper and lower two LEDs are formed into an upward and downward triangular shape, respectively. When it is determined that the relationship is appropriate, only the center green LED is turned on and the other red LEDs are turned off.
If the comparison circuit 20 determines that the activity has a low compression ratio and can still increase the compression ratio, as shown in FIG. 4B, it blinks, goes off, goes off, and turns off the compression ratio. To raise. Further, the comparison circuit 20
If it is determined that the compression rate is high and the image quality degradation is conspicuous for the activity, then as shown in FIG.

The present invention is not limited to the above-described embodiment, but can be implemented with various modifications without departing from the spirit and scope of the present invention. For example, in the case of an industrial camera device, the determination result may be displayed on a monitor connected to the camera device.

[0018]

As described in detail above, according to the present invention,
An extremely good electronic still camera device that enables a user to easily select and set an appropriate compression ratio can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an electronic still camera device according to the present invention.

FIG. 2 is a diagram showing a display unit in the embodiment.

FIG. 3 is a view for explaining a display mode of the display unit.

FIG. 4 is a diagram showing another example of the display unit.

FIG. 5 is a block diagram showing a conventional electronic still camera device.

[Explanation of symbols]

11: lens unit, 12: CCD, 13: signal processing circuit, 14: A / D conversion circuit, 15: compression circuit, 16:
Compression ratio setting operation unit, 17: I / F circuit, 18: recording medium, 19: activity calculation circuit, 20: comparison circuit,
21: display unit, 22: finder.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N 5/76-5/956 H04N 5/225 H04N 7/24-7/68

Claims (3)

(57) [Claims] [Claim 1] an optical image of the photographed object is converted into digital image data, recorded on a recording medium by applying accompanying data compression code amount control based on the selectively set compression ratio electronic In the still camera device, the compression ratio
Compression rate setting means for setting the image data; calculating means for calculating the activity of the digital image data;
A reference value that is related to the compression ratio appropriate for the activity
The activity calculated based on the reference value.
Comparing means for comparing the reference value with the reference value, and based on the comparison result.
It is possible to increase the compression ratio of the data compression process.
And a display means for performing a display indicating that the electronic still camera is operating. 2. The method according to claim 1, further comprising the steps of:
Converts to image data, based on the compression rate set selectively
Recording medium with data compression processing with code amount control
In the electronic still camera device for recording at the
Compression ratio setting means for setting the digital image data
Calculating means for calculating the activity of the image data,
A table showing the relationship between the compression ratio appropriate for the activity
Is calculated based on this table.
Comparison means for comparing the values of the table with the values of the table
Increase the compression ratio of the data compression process based on the result
Indication that you can, need to lower the compression rate
Display means for displaying the presence of
An electronic still camera device. 3. An optical image of a photographed subject is converted into a digital image.
Converts to image data, based on the compression rate set selectively
Recording medium with data compression processing with code amount control
In the electronic still camera device for recording at the
Compression ratio setting means for setting the digital image data
Calculating means for calculating the activity of the image data,
A table showing the relationship between the compression ratio appropriate for the activity
Is calculated based on this table.
Comparison means for comparing the values of the table with the values of the table
Increase the compression ratio of the data compression process based on the result
The first indication that you can
Display indicating that the compression rate needs to be lowered
Display means for performing a third display indicating that
An electronic still camera device characterized by the above-mentioned.