JPH06350858A - Information processor - Google Patents

Abstract

PURPOSE:To set the compression/non-compression of picture data to be appropriate. CONSTITUTION:A picture data sampling means 13 extracting a part of picture data stored in a picture memory 12 as sampling data, a sampling data compression means 14 compressing sampling data and outputting compressed sampling data and a data transfer control means 17 comparing the data size of sampling data with that of compressed sampling data, compressing picture data of the picture memory 12 in a data compression means 16 so as to store it in an external storage means 18 when compression is appropriate and storing picture data of the picture memory 12 to the external storage means 18 as it is when compression is inappropriate are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus for determining whether or not image data is suitable for compression, and if the data is suitable for compression, it is automatically compressed and stored in an external storage means.

[0002]

2. Description of the Related Art In recent years, an increasing number of information processing apparatuses have a function of taking in image data from image data input means such as a scanner, storing it in an external storage means, and processing the image data in various ways. In general, most of this image data has a large data size, and the capacity of the external storage means in which the image data should be stored is limited.

[0003]

Therefore, an information processing apparatus having a function of compressing image data and then storing the compressed image data in an external storage means has appeared. In such an information processing apparatus, image data is compressed and stored as compressed image data in an external storage means, and the stored compressed image data is decompressed and used. Here, if the data size of the compressed image data is considerably smaller than the data size of the image data, the capacity of the external storage means can be effectively utilized, which is beneficial.

Image data includes multi-tone image data and image data without tone. Among them, multi-tone image data includes, for example, landscape image data, in which a pseudo intermediate color is represented by halftone dots or dither processing, and image data without tone is, for example, a trademark. Like a sample, it is either pure white or pure black.

In the multi-gradation image data, the bit information of "0" and the bit information of "1" are distributed almost randomly, and the image data generally has a data size even if compressed. It is difficult to reduce the size, and conversely, the data size may increase due to compression. Therefore, it is generally said that it is better not to compress multi-tone image data. On the other hand, in image data having no gradation, generally the same bit information is often continuous, and it is generally said that the image data has a considerably small data size due to compression. Therefore, it is said that image data without gradation is suitable for compression. However, the above is a principle, and this may not always be the case depending on the image data.

In the conventional information processing apparatus, whether or not to compress the image data is left to the empirical judgment of the user. However, whether or not individual image data is suitable for compression cannot be known until after actual compression. Further, it is a technical skill for the user to determine whether compression is appropriate, and it is difficult to understand. Therefore, some users may not compress all the image data or, conversely, may not compress all, without considering the appropriateness of the compression. Therefore, in the conventional information processing device, the image data to be actually compressed is stored in the external storage means without being compressed, and the capacity of the external storage means is wasted, or conversely, the image data that should not be compressed is stored. There is a problem in that the data size is expanded by compressing, and an extra processing time is consumed for the compression processing.

Therefore, an object of the present invention is to provide an information processing apparatus capable of determining whether or not image data compression is appropriate and automatically compressing only those suitable for compression.

[0008]

In view of the above problems, in the present invention, an image data sampling means for extracting a part of the image data stored in the image data storage means as sampling data, and the sampling data are compressed. Then, the sampling data compression means for outputting the compressed sampling data is compared with the data size of the sampling data and the compressed sampling data. If the compression is appropriate, the image data of the image data storage means is compressed by the data compression means, In addition to storing the image data in the image data storage means in the external storage means as it is, the data transfer control means stores the image data in the external storage means.

[0009]

According to the present invention, with the above construction, the image data is inputted from the image data input means and the image data is stored in the image data storage means. Then, the image data sampling means extracts only a part of the image data as sampling data and passes it to the sampling data compression means. Then, the sampling data compression means compresses the sampling data to generate compressed sampling data. As a result, it is possible to know the original data size and the compressed data size of the sampling data, and the data transfer control means compares these data sizes to determine whether the entire image data is suitable for compression.
If the result of this determination is that compression is appropriate, the data transfer control means causes the data compression means to compress all of the image data in the image data storage means and then stores it in the external storage means.
On the contrary, when the compression is not suitable, the data transfer control means stores the entire image data in the external storage means as it is without compressing it.

That is, since only a part of the image data is compressed on a trial basis to determine whether or not the compression is appropriate, the appropriateness of the compression can be determined in an extremely short time compared with the case where the entire image data is compressed on a trial basis. Further, since a part of the individual image data is actually compressed and the propriety of the compression is determined, the propriety of the compression can be automatically determined remarkably accurately as compared with the case where the user empirically determines the propriety of the compression. Therefore, the image data suitable for compression is stored in the external storage means after being compressed, and the capacity of the external storage means can be effectively utilized. Further, the image data that is not suitable for compression is stored in the external storage means as it is, so that it is possible to save the unnecessary processing time for increasing the data size and compressing the image data.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram of an information processing apparatus according to an embodiment of the present invention, and FIG. 2 is a logical block diagram of essential parts of the information processing apparatus.

In FIG. 1, 1 is a ROM (read only memory) which stores a control program according to the flowcharts of FIGS. 3 and 4, and 2 is a CPU which executes the control program of the ROM 1 and controls each element described later. (Central processing unit) 3, reference numeral 3 is a RAM (random access memory) provided with an area for an image memory 12 to be described later, reference numeral 4 is a keyboard for a user to input necessary information such as operation commands, and reference numeral 5 is described later. The external storage unit 18 is a hard disk device provided with an area for storing image data (including uncompressed original image data and compressed compressed image data). Of course, an optical disk device may be used instead of the hard disk device 5. Reference numeral 6 is a CRT (cathode ray tube) for displaying information necessary for the user such as input image data and processing status, and 7 is a scanner as image data input means 11 described later, which is a designated area of a document (not shown). Is read to generate image data.

In FIG. 2, 11 is an image data input means such as a scanner 7 for inputting image data, 12 is an image memory for storing the image data generated by the image data input means 11, and 13 is an image memory 12. It is an image data sampling means for extracting a part of the original image data as sampling data and outputting it to the sampling data compression means 14 and the compression rate generation means 15.

Next, the extraction conditions in the image data sampling means 13 will be described with reference to FIG. Figure 5
Inside, S is the whole of the original image data, and A1 to A3 indicate areas to be extracted as sampling data. In the present embodiment, the sampling data for the three lines of the center, the center of the upper half, and the center of the lower half of the image data are used. The area to be extracted as the sampling data is specified by specifying the address in the image memory 12. Note that the accuracy of the compression suitability determination depends on the designation. Here, if the amount of sampling data to be extracted is increased, the accuracy is increased, but the time required for the suitability determination is increased. Therefore, the amount of this sampling data is appropriately set in advance in consideration of various circumstances, but it is usually about the example shown in FIG.
In addition, the position extracted as sampling data is shown in FIG.
As shown in FIG. 5, the target may be the upper and lower targets, or may be set randomly.

In FIG. 2, reference numeral 14 is a sampling data compression means for compressing the sampling data extracted by the image data sampling means 13 into compressed sampling data on a trial basis, and outputting this compressed sampling data to the compression ratio generating means 15, 15. Inputs the original sampling data from the image data sampling means 13 and the compressed sampling data from the sampling data compression means 14, and the compression rate of the sampling data =
Calculate the compression rate from (data size of compressed sampling data) / (data size of original sampling data),
It is a compression rate generation means for outputting to the data transfer control means 17. Reference numeral 16 is a data compression means for compressing the original image data and outputting it to the data transfer control means 17 when the original image data (all) is inputted from the data transfer control means 17.
Reference numeral 7 refers to the compression rate input from the compression rate generation means 15 to determine whether the image data is suitable for compression. If not, the image data in the image memory 12 is indicated by the arrow N1 (broken line) in FIG. (Whole) is stored in the external storage means 18 as it is without being compressed, and if appropriate, the arrow N2 in FIG.
As indicated by (chain line), it is a data transfer control means for compressing the image data (all) by the data compression means 16 into compressed image data and then storing the compressed image data in the external storage means 18. The image data sampling means 1
3, sampling data compression means 14, compression rate generation means 15, data transfer control means 17, and data compression means 16
Is realized by the CPU 2 executing the control program of the ROM 1.

Although the sampling data compressing means 14 is provided separately from the data compressing means 16 in FIG. 2, the sampling data compressing means 14 may be omitted so that the data compressing means 16 also has a role of compressing the sampling data. .

The information processing apparatus according to the present embodiment has the above-mentioned configuration, and the processing steps thereof will be described below with reference to FIGS. As shown in FIG. 3, the user first sets a document on the scanner 7 and gives an instruction to input image data from the keyboard 4. Then, the image data output from the scanner 7 is stored in the image memory 12, and the image data is displayed on the CRT 6 (step 10). next,
When the user gives an instruction to save the image data from the keyboard 4, the data saving process of FIG. 4 is performed (step 20).

Next, the storage process of step 20 will be described. First, the image data sampling means 13 extracts the original sampling data from the image data in the image memory 12 according to the extraction conditions shown in FIG. 5, and outputs it to the sampling data compression means 14 and the compression rate generation means 15 (step 21). Then, the sampling data compression means 14 converts the compressed sampling data into the compression rate generation means 1
5, the compression rate generation means 15 obtains the compression rate from the above equation, and outputs the obtained compression rate to the data transfer control means 17 (step 22). Next, the data transfer control means 17
Compares this compression rate with a predetermined value α (step 2
4). The predetermined value α is, for example, 90%. If the compression rate is equal to or less than the predetermined value α, the data transfer control means 17
Determines that the image data is suitable for compression. Then, the image data (all) in the image memory 12 is compressed by the data compression means 16 and then stored in the external storage means 18 (steps 25 and 26). On the other hand, if the compression rate exceeds the predetermined value α, the original image data is stored in the external storage means 18 as it is (steps 24 and 26).

The predetermined value α is determined in consideration of the time required for compression processing, the capacity of the external storage means 18, the time required for input / output of the external storage means 18, and the like. Further, the sampling data compression means 14 and the like are provided with a function of measuring the time required for compression of the sampling data, and the data transfer control means 17 is also made to input the time information required for this compression, and the time required for compression together with the compression rate. The appropriateness of compression may be determined in consideration of the above. By doing so, it is possible to deal with a user who attaches great importance to the processing time of image data.

Although the compression rate is used as a criterion for determining whether compression is appropriate, the method of calculating the compression rate is not limited to this embodiment.

[0022]

According to the present invention, the image data sampling means for extracting a part of the image data stored in the image data storage means as sampling data, and the sampling data compression for compressing the sampling data and outputting the compressed sampling data. Means for comparing the data sizes of the sampling data and the compressed sampling data with each other, and if the data is suitable for compression, the image data in the image data storage means is compressed by the data compression means and stored in the external storage means. In this case, since the data transfer control means for storing the image data in the image data storage means as it is in the external storage means is provided, an appropriate compression process can be performed without the user being aware of a specialized concept such as image data compression. It can be carried out. In addition, whether the compression of the image data is appropriate,
Since it can be determined automatically in a short time and accurately based on the actual image data, and only the image data to be compressed can be compressed, the capacity of the external storage means can be effectively utilized without wasting it. .

[Brief description of drawings]

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

FIG. 2 is a logical block diagram of essential parts of an information processing apparatus according to an embodiment of the present invention.

FIG. 3 is a flowchart of the information processing apparatus according to the embodiment of the present invention.

FIG. 4 is a flowchart of an information processing device according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of sampling data extraction conditions in the information processing apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 11 Image Data Input Means 12 Image Memory 13 Image Data Sampling Means 14 Sampling Data Compressing Means 16 Data Compressing Means 17 Data Transfer Control Means 18 External Storage Means

Claims (2)

[Claims] 1. An image data storage means for storing image data input from the image data input means, and an image data sampling means for extracting a part of the image data stored in the image data storage means as sampling data.
Sampling data compression means for compressing this sampling data and outputting compressed sampling data is compared with the data size of the sampling data and the compressed sampling data. If the compression is appropriate, the image data of the image data storage means is compressed by the data compression means. An information processing apparatus which stores the image data in the external storage means after being compressed by the external storage means, and stores the image data of the image data storage means in the external storage means as it is when the compression is unsuitable. . 2. The information processing apparatus according to claim 1, wherein the data transfer control unit determines that the compression is appropriate when the compression rate obtained by dividing the data size of the compressed sampling data by the data size of the sampling data is equal to or less than a predetermined value. .