JPH02248180A - Picture information coding device - Google Patents

Abstract

PURPOSE:To easily attain the efficient coding of picture information by setting automatically proper coding mode in response to the activity of an input picture or information quantity. CONSTITUTION:An information quantity calculation circuit 1 calculates the information quantity of picture information or activity from an input terminal (a). Then a coded mode table 2 based on the information quantity or the like outputs the efficient mode information and a data with a quantized width whose picture quality deterioration is not visually remarkable. A quantizer 5 quantizes the picture information from a frame memory 4 with a quantized width from the table 2 and outputs the result to an output terminal (b) via a variable length coding circuit 3. Thus, when the information quantity calculated by the circuit 1 is too much, the coding mode is selected from the table 2 so as to reduce it and when the information quantity is less, the coding mode is selected from the table so as to increase the quantity. Thus, easily efficient coding is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an image information encoding device that compresses the amount of image information.

(Prior art) In a conventional image information encoding device such as an electronic camera, when trying to capture an image, the amount of code is increased for a detailed image, and the amount of code is increased for a relatively smooth image. In this case, the amount of code decreased or became almost non-existent. In other words, the image to be captured could not be captured as a standard image.

(Problem to be solved by the invention) In other words, when setting the code amount (encoding mode), if the user does not select a mode suitable for the latter input image, the image quality will deteriorate significantly or the code amount will decrease. Compression could not be performed efficiently. Furthermore, even when setting the image quality, the image quality is always higher than the set image quality, making it difficult to efficiently compress the amount of code.

In order to solve these problems, the present invention provides an image processing system that can efficiently set the amount of code without requiring a skilled user, and can also efficiently compress the amount of code when compressing an image. The purpose is to provide an information encoding device.

[Structure of the invention]

(Means for Solving the Problems) This invention is an image information code that calculates the activity or information amount (distribution) of an input image, calculates a preset appropriate encoding mode from that value, and performs encoding. It is a device that converts

(Function) Since an appropriate encoding mode is automatically set according to the amount of information of the input image, the image information can be easily and efficiently encoded. Also, when performing compression, highly efficient compression encoding can be performed as well.

(Example) FIG. 1 is a diagram showing an example of the present invention. The information amount division circuit 1 calculates the information amount or activity of the image information (-screen ticket) input from the input terminal a. Based on this amount of information or activity, the encoding mode table 2 outputs efficient mode information (recommended encoding mode) and quantization width data in which image quality deterioration is not visually noticeable. At this time, the frame memory 4 outputs the image information inputted earlier from the input terminal a. The quantizer 5 quantizes the image information using the quantization width output from the encoding mode table. The DPCM 6 outputs difference data from this quantized image information (quantized data) with the quantized data input one pixel before. The variable length encoder 3 encodes the quantizer (or quantizer and encoding mode) output from the encoding mode table 2, and then
The differential data (for one screen) output from the DPCM 6 is variable-length encoded and output to the output terminal.

In other words, the amount of information calculation circuit 1 calculates the amount of information of the input image, and when the amount of information is too large, the encoding mode is selected from Table 2 to reduce the amount of information. The encoding mode is selected to increase the number of times.

Next, another embodiment will be described using the block diagram shown in FIG.

Here too, the information amount calculation circuit 1 calculates the information amount or activity (for one screen) of image information inputted from the input terminal a. From this amount of information or activity, the encoding mode table 2 outputs efficient encoding mode information and quantization width data in which image quality deterioration is not visually noticeable. Then, the frame memory 4 outputs the image information inputted earlier through the input terminal a, and the image information is cosine-transformed by the cosine transformation device 7. The quantizer 5 quantizes and outputs the cosine-transformed data using the quantization width output from the encoding mode table.

The variable length encoder 3 encodes the quantization width (or quantization width and encoding mode) output from the encoding mode table 2, and then outputs the quantization width (for one screen) from the quantizer 5.
The quantized data is variable-length coded and output to the output terminal.

Also, compared to the embodiment shown in FIG. 2, the one in FIG.
The partial information amount calculation circuit 8 calculates the information amount from the frame memory 4 in units of blocks to be cosine transformed. The bit allocation determining circuit 9 determines the encoding mode output from the encoding mode table 2, the information amount for one screen output from the information amount calculation circuit 1, and the block unit information output from the partial information amount calculation circuit. From this amount, the amount of code to be limited to the encoded block is calculated and output to the variable length encoder 3. The variable length encoder 3 limits the encoding of the quantized data so that the code amount of the block to be encoded is approximately less than this limited code amount. As a result, the amount of code for one screen is finely adjusted.

FIG. 4 is a diagram showing an example of an encoding mode table used in the embodiments shown in FIGS. 1 to 3. As the amount of information increases, the amount of code is gradually increased. Furthermore, the quantization width is increased depending on the amount of information.

FIG. 5 is a block diagram showing another embodiment of the invention.

The information amount calculation circuit 1 calculates the information amount or activity (for one screen) of image information inputted from the input terminal a. From this amount of information or activity, the encoding mode table 10 outputs image quality information and quantization width for each mode. The display device 11 displays the degree of image quality deterioration in each encoding mode from the image quality information for each mode output from the encoding mode table 10. When the encoding mode information determined from the displayed information is input from the input terminal C, the selector 12 outputs the quantization width for the selected mode. At this time, the image information input earlier is output from the frame memory 4 and the cosine transformer 7
is input. The quantizer 5 quantizes the data input from the cosine transform device 7 using the quantization width output from the selector 12 and outputs the result. The variable length encoder 3 encodes the quantization width output from the selector 12 (and the encoding mode input from the input terminal C), and then outputs the quantization width (for one screen) from the quantizer 5. The quantized data is variable-length coded and output to the output terminal. As described above, according to the present invention, it is possible to select an encoding mode after knowing the degree of image quality deterioration that is close to the actual degree.

FIG. 6 is a diagram showing an example of an encoding mode table used in the embodiment of FIG.
As the number increases, the quantization width is gradually increased, and the image quality is gradually lowered.

FIG. 7 is a diagram showing an embodiment of the electronic camera of the present invention,
This will be explained using the flow diagram shown in FIG. A control circuit 100 after shutter ON (step 1), not shown;
Step 2) The signal processing circuit 102 generates a luminance signal and a color difference signal for one frame image by driving the CCD 10I via the drive circuit 113 (Step 3). The luminance signal and the color difference signal each pass through a band pass filter (not shown), and the output value of the band pass filter is calculated by an information amount calculation circuit 103.
1 point screen score is calculated at (step 4). Based on this integral value, the estimated S/N calculation circuit 104 estimates the nature of the image, whether there are many flat parts or a fine pattern. Based on this integral value, S/ and N in each encoding mode (how many bits of data are used for one screen) are estimated. The correlation between the integral value and the S/N value in each mode may be investigated in advance using many images. The calculated estimated S/N (or image quality rank...high image quality, average, poor, etc.) is displayed on the finder 105 (step 5).

The mode is set by the setting unit 106 according to the display (step 6).

On the other hand, the luminance signal and color difference signal are written to the frame memory 107 (step 7), read out from the frame memory after the mode is set, converted by the cosine conversion circuit 108 (step 8), and then quantized in the set mode. A value is selected from the table 109, and this value is used in the quantization circuit 1.
10 (step 9), encoded by the encoding circuit 111 with a code such as a Huffman code (step 10), and written to the memory card 112 (step 11). In this example, the mode setting is performed externally. However, after calculating the estimated S/N, a mode (standard) in which the image quality rank is normal may be automatically set, and the mode or the estimated S/N at that time may be displayed on the finder.

In addition, the example in Figure 7 shows an example using frame memory, but when the shutter is pressed halfway, the amount of information is calculated and the mode is set, and then the shutter is pressed fully and cosine transformation, quantization, and encoding are performed. Memory card data may also be written. This state will be explained with reference to the flow diagram in FIG. In this case, the control circuit 100 in FIG. 7 is set to perform two drives: when the shutter is pressed halfway and when the shutter is pressed fully.

With the shutter pressed halfway (step 1), first press the CC button.
When the DIOI is activated, step 2) and the signal processing described above (
Step 3), after calculating the amount of information (Step 4) and automatically setting the mode (Step 4), the finder 105
The mode is displayed (step 6). At this point, decide whether to accept this state (for automatic setting) or change to another mode (manual mode setting (step 8))
) is determined (step 7), the shutter is fully pressed to start imaging (step 9), and at this timing C C
D 101 is driven (step 10) and subjected to the signal processing described above (step 11). Then, the imaged signal as described above is subjected to cosine transformation (step 12).
Quantization (step 13) and encoding (step 14) are performed, and the data is written to the memory card 112 (step 15).

In addition, in the above embodiment, when the amount of information is calculated and the mode is set (automatic or manual), if there is a large difference in image quality from the preset standard image quality, a warning or light etc. It can also be configured to notify the user.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to select the encoding mode automatically or after knowing the actual image quality deterioration, and it is possible to select the encoding mode efficiently without requiring any skill. Image information can be encoded and compressed.

[Brief explanation of drawings]

1 to 3 are block diagrams showing embodiments of the present invention,
FIG. 4 is a diagram showing an example of the encoding mode table used in these embodiments, FIG. 5 is a block diagram showing another embodiment of the present invention, and FIG. 6 is a diagram showing an example of the encoding mode table used in this embodiment. A diagram showing an example, FIG. 7 is a diagram showing an application example of the present invention,
8 to 9 are flowcharts for explaining FIG. 7. 1... Information amount calculating circuit 2.10... Encoding mode table 3 Variable length encoder 5 Quantizer 8... Partial information amount calculating circuit 9... Bit allocation determining circuit 11...・Display device 12...Selector agent Patent attorney Noriyuki Chika Yudo Mitsuyuki Matsuyama

Claims (3)

[Claims] (1) An image information encoding device that calculates the activity or information amount of an input image and automatically sets a recommended encoding mode (code amount) based on the calculated value. (2) An image information encoding device that calculates the activity or information amount of an input image and displays image quality mode information for each encoding mode. (3) A recommended encoding mode is automatically set by pressing a shutter, the encoding mode is displayed in a finder, and data encoded in the recommended encoding mode is recorded. image information encoding device.