JP3131235B2 - Image processing 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 image processing apparatus and, more particularly, to an image processing apparatus for compressing and encoding an image taken by an electronic still camera or the like and storing it.

[0002]

2. Description of the Related Art One of the techniques for performing high-efficiency compression coding on natural images is a method in which orthogonal transform is combined with variable-length coding, and is being adopted as an international standard for color natural image coding. is there. In such an encoding method, by controlling specific parameters, it is possible to control the image quality of an image after decoding and the amount of code in decoding. Note that, between the code amount and the image quality, the larger the code amount, that is, the smaller the degree of compression, the smaller the deterioration of the image quality from the original image, and conversely, the smaller the coding amount, that is, the smaller the degree of compression, There is a relationship that the larger the value, the greater the deterioration of the image quality from the original image.

[0003]

However, at the time of encoding, since adaptive processing using local correlation of images is performed, highly efficient compression according to the characteristics of the processed image can be performed. On the other hand, the relationship between the code amount control parameter and the obtained code amount differs for each processed image. For this reason, even if encoding is performed with the same code amount control parameter, generally, an image with a fine pattern has a large code amount, and a flat image with many solids has a small code amount.

Therefore, when such a compression coding technique is applied to, for example, a digital still camera or the like, there is a problem that the number of images that can be recorded on one recording medium is usually not uniquely determined. In order to avoid this, in order to keep the code amount per image constant, for example,
There has been proposed a method in which data for code amount control is calculated in a 1-bus memory, and data is controlled in a 2-bus memory.

However, in such a method of controlling the code amount per image to be constant, there is a problem that the image quality is not constant because the code amount is constant for each image. Further, the user cannot arbitrarily select the image quality. Further, there is a problem that real-time processing is often difficult.

By the way, in such an electronic still video camera that digitally compresses and encodes an image pickup signal output from an image pickup device and records it on a recording medium, the image quality of an object to be shot can be arbitrarily set for general users. Whether the setting can be performed is considered to be extremely important information for photographing. An object of the present invention is to enable a user to arbitrarily set the image quality of a storage target in an image processing device such as a digital still video camera using such a variable-length coding method.

[0007]

An image processing apparatus according to the present invention.
Is an imaging device that photoelectrically converts an image to obtain an analog image signal.
Converting the analog image signal into a digital image signal
Conversion means for performing compression rate setting means for setting a compression rate;
Code the digital image signal at the set compression rate
Encoding means for encoding, and the encoded digital image
Storage means for storing a signal, and the encoded digital data
Decoding means for decoding an image signal,
Compression ratio calculation means for calculating the compression ratio of a digital image signal
And both the decoded image and the calculated compression ratio
And a display means for displaying
Things.

[0008]

According to the image processing apparatus of the present invention, an image is photoelectrically converted by an image pickup means to obtain an analog image signal. This is converted into a digital image signal, encoded to the compression ratio set by the compression ratio setting means, and the encoded digital image signal is stored in the storage means. In addition, encoded digital
Decodes image signals and encodes digital images
The compression ratio of the signal is calculated, and both are displayed on the display means. table
The indicating means, for example, while the photographing means is photographing the subject,
The calculated compression ratio and the decoded image are displayed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an image processing apparatus according to the present invention will be described below in detail with reference to FIGS. In FIG. 1, reference numeral 1 denotes a camera as an imaging unit, and
CD (Charge Coupled Device)
And the like. The camera 1 is controlled by a drive unit (not shown), and photoelectrically converts an image of a subject to output an analog image signal. 2
Is an A / D converter as a conversion means for converting an analog image signal output from the camera 1 into a digital image signal.

Reference numeral 3 denotes a code amount adjustment dial as compression ratio setting means for setting the compression ratio to an arbitrary value. Reference numeral 4 denotes an image compression encoding unit as encoding means for performing encoding based on the compression ratio adjustment parameter value. An ADCT method is adopted as a compression encoding method in the image compression encoding unit 4. As a method of compressing from the compression amount adjustment parameter, for example, compression is performed by dividing or multiplying the quantization matrix by the compression amount adjustment parameter. It is performed in various ways, such as by changing the amount. The encoded image data in the image compression encoding unit 4 is supplied to a compression ratio calculation unit 5 for calculating a compression ratio and a decoding unit 6 as decoding means for decoding .

Reference numeral 7 denotes a display device as display means, which is compressed and encoded by the image compression encoding unit 4 and then decoded by the decoding unit 6.
The decoded image is displayed again , and the compression rate calculation unit 5
The compression ratio calculated by the above is displayed. As the display device 7, for example, in the case of an electronic still camera, a liquid crystal display (LCD) is often used, but any other method may be used. Reference numeral 8 denotes a storage unit serving as storage means, which is configured by an electric storage medium such as a semiconductor memory, an IC card, and a magnetic disk. The storage unit 8 stores information used for compressing image data such as data encoded by the image compression encoding unit 4 and a code amount adjustment parameter.

Next, the operation of the thus configured image processing apparatus will be described. An image of a subject (not shown) is photoelectrically converted by the camera 1, and an analog image signal is supplied to the A / D converter 2. The analog image signal supplied to the A / D converter 2 is converted into a digital image signal, temporarily stored, and supplied to the image compression encoder 4. The image compression encoding unit 4 performs compression encoding of the digital image signal supplied from the A / D conversion unit 2 based on the compression ratio adjustment parameter value supplied from the code amount adjustment dial 3 .

The image data which has been encoded by the image compression encoding unit 4 and whose total data amount has been reduced is compressed by a compression ratio calculation unit 5 .
The compression ratio is calculated as a percentage of the original code amount.
Is calculated on the display device 7. Also,
The compressed image data is decoded and reproduced by the decoding unit 6 and displayed on the display device 7. The display of the image after the compression ratio and the decoding is displayed while the camera 1 is shooting the subject or during the compression ratio setting mode.
By checking the image quality of the image displayed on the display device 7, it is possible to adjust the code amount adjustment dial 3 so that the desired image quality is obtained.
it can. The adjusted image is displayed again on the display device 7.
It is.

When the compression ratio is determined by the photographer while looking at the display device 7, the encoded data at that time is stored in the storage unit 8.
Is supplied and stored. At this time, information used to compress the image data is also stored.

The code amount adjusting dial 3 includes, for example,
For example, mark “High image quality”, “Normal”, “High compression”, etc.
In the image compression encoding unit 4, the precomputed pressure
It is also possible to compress based on the reduction amount adjustment parameter.
You.

As another embodiment of the present invention, a viewfinder of a camera can be used for the display device 7. As shown in FIG. 2, the viewfinder is installed so that the photographer can constantly monitor the image of the field of view to be photographed. In the case of this embodiment, the viewfinder is an electronic display means such as a small CRT. When controlling an image with the code amount adjustment dial, input of an image from the camera, A /
If the D conversion, encoding, decoding, and display are all processed in real time, the photographer can always see the change in the image while correcting it with the code amount adjustment dial, and the image quality can be adjusted very easily. become. At this time, the above-mentioned compression ratio can be simultaneously displayed in the viewfinder in real time.

[0017]

According to the present invention, a compression-encoded image
Both the data compression ratio and the decoded image of the image data
The display allows the user to view the actual compressed image.
Since the correct compression ratio can be checked at a glance , the user can easily set the image quality of the subject, and can store an image of a quality suitable for the purpose of the user, and further adjust the number of stored images (capacity). It becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of an image processing apparatus according to the present invention.

FIG. 2 is an external view of an electronic still camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera 2 A / D conversion part 3 Code amount adjustment dial 4 Image compression encoding part 5 Compression rate calculation part 6 Decoding part 7 Display device 8 Storage part

Claims (3)

(57) [Claims] An image is photoelectrically converted to an analog image signal.
Imaging means for obtaining the analog image signal and a digital image
Conversion means for converting to a signal, and compression ratio setting for setting the compression ratio
Setting means, and the digital image at the set compression ratio.
Encoding means for encoding the signal; and
Storage means for storing a digital image signal;
Decoding means for decoding the decoded digital image signal;
Compression to calculate the compression ratio of the encoded digital image signal
Rate calculating means, the decoded image and the calculated pressure
Display means for displaying both of the reduction ratios.
Image processing apparatus. 2. The display means according to claim 1 , wherein said photographing means captures an image.
While displaying the decoded image and the calculated compression ratio
The image processing apparatus according to claim 1, wherein: 3. A display device comprising a viewfinder.
3. The image processing apparatus according to claim 1, wherein: