JPH099070A - Image processing system and its color image processing method - Google Patents

Abstract

PURPOSE: To enhance the efficiency of a compression processing in a color image so as to improve the efficiency of the image processing in result by using a binary image encoding system in a system where image information adding the color image is processed. CONSTITUTION: An encoding processor 2 converts color image information into binary image information in inputted image information based on designated color area information. Then, binary image information corresponding to color image information is encoded by the prescribed binary image encoding system together with binary image information of a black and white image. A decoding processor 6 decodes encoding image information into original binary image information or original color image information based on the analysis result of color area information. Therefore, since color image information is encoded by the binary image encoding system, the information quantity of encoding image information is drastically reduced in comparison with the encoding processing by color image encoding system so that efficiency in the compression processing of the color image is attained in result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image information image processing system having image information coding means and decoding means, and in particular, image information in which black and white images and color images are mixed.

[0002]

2. Description of the Related Art Conventionally, image processing systems for black and white images are
Binary image information in which one pixel is handled by 1 bit in which a white image (background) is "0" and a black image (foreground) is "1" is processed.

Specifically, there is a system for processing text image information obtained by scanning a sheet with a scanner (image input device), for example. For such a binary image processing system, a binary image encoding method showing a high image compression rate has been developed.

In contrast to this black-and-white image, one pixel of a color image is represented in RGB (or CMYK) color space by a few bits or a few bytes (usually 3 bytes).
The same coding method as the value image coding method cannot be applied.
That is, there is an encoding method for color images, and color image information having a large information amount with respect to a binary image is compressed and processed.

By the way, there is a system for processing image information in which a color image is mixed in a text image as described above. In this text image, most of the information is a black-and-white binary image, and only some characters and figures are color images using several kinds of colors. That is, even if such binary image information occupies the majority, since the color image exists, the binary image encoding system cannot be used, and the monochrome image is also encoded by the color image encoding system. Will be.

[0006]

In a system for processing image information such as a text image which is mostly a black and white binary image and a part of which is a color image, the binary image is also used for the color image. Image compression processing is performed by the encoding method of. In the color image coding method, the coded information amount becomes much larger than the binary image coding method in accordance with the color image information having a large amount of information. Therefore, even though the color image is partial, it is necessary to store the coded image information having a large amount of coded information and to perform the coding process, as in the system adopting the coding method for the color image. And

An object of the present invention is to realize an efficient compression process of a color image by utilizing a binary image coding method in a system for processing image information including a color image, and as a result, the image processing To improve efficiency.

[0008]

According to the present invention, an input image is input in an image processing system for encoding image information in which a binary image which is a black and white image and a color image are mixed and decoding the original image information. Converting means for detecting color image information from the information and converting the color image information into binary image information; encoding means for encoding the binary image information by a predetermined binary image encoding method; And a decoding means for decoding image information into original binary image information or color image information.

[0009]

In the present invention, color image information in the image information input by the image input means is converted into binary image information. The encoding means encodes the binary image information corresponding to the color image information together with the binary image information of the monochrome image by a predetermined binary image encoding method. The decryption means
The encoded image information is decoded into original binary image information or original color image information. Therefore, since the color image information is encoded by the binary image encoding method, the information amount of the encoded image information can be significantly reduced as compared with the encoding processing by the color image encoding method. As a result, the efficiency of color image compression processing can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main part of the image processing system of this embodiment, and FIG. 2 is a conceptual diagram showing an example of a text image and coded image information related to the image processing of this embodiment, and FIG. FIG. 4 is a flow chart for explaining the image processing of this embodiment. (System Configuration) As shown in FIG. 1, the image processing system according to the present embodiment converts a monochrome image or a color image input from an image input device 1 such as a scanner into a predetermined binary value by an encoding processing device 2. Encoding processing by the image encoding method is performed.

The coding processing device 2 has a coding device 3 for executing a coding process and a color area information designating device 4. The color area information specifying device 4 is means for specifying color area information for specifying a color in a color image and its area (size and shape). The color area information specifying device 4 may be a method of automatically generating color area information from color image information input from the image input device 1 or a method of specifying from outside.

The encoding device 3 sets the color information in the color image to "0" or "1" based on the designated color area information.
Of the binary image information, and the binary image information is encoded by a predetermined binary image encoding method. At the time of this encoding processing, the encoding information obtained by encoding the color area information is added (see FIG. 2B). Further, the encoding device 3 encodes the binarized image information of the monochrome image.

Further, this system has an image information storage device 5, a decoding processing device 6 and an image output device 9. The image information storage device 5 is a storage device for storing the encoded image information (monochrome image and color image) output from the encoding processing device 2, and is composed of, for example, a hard disk device. The image output device 9 is a device for displaying or printing in color the original black and white image information or color image information output from the decoding processing device 6.

The decoding processing device 6 has a decoding device 7 and a color area information analyzing device 8 for executing the decoding process. The color area information analysis device 8 analyzes the color area information of the encoded image information read from the image information storage device 5, and outputs the analysis result for decoding to the original color image information to the decoding device 7. .

The decoding device 7 decodes the coded image information into the original monochrome image information, and also decodes the coded image information into the original color image information based on the analysis result from the color area information analysis device 8. To do. The decoding device 7 outputs the decoded image information to the image output device 9. (Encoding process) In this embodiment, as shown in FIG. 2A, a text image recorded on a sheet 20, for example, is an image in which text information 21 that is a monochrome image and color images 22 and 23 are mixed. Image processing is assumed. Here, sentence information 2
In the case of 1, one pixel having a white image (background) as “0” and a black image (foreground) as “1” is represented by 1-bit binary image information.

The color image 22 is a rectangular color image area, and the character string of "title" is a red color image 22.
a, and the background (hatched portion) has a blue color image 22.
It consists of b. The color image 23 includes a blue color image 23a, a green color image 23b, a yellow color image 23c, and a red color image 23d.

Next, referring to the flowchart of FIG.
The encoding process of this embodiment will be described. First, the image input device 1 such as a scanner scans the text image 20 to input, for example, image information for each line (step S1). The encoding processing device 2 encodes the image information input by the encoding device 3 by a predetermined binary image encoding method. In this encoding process, as indicated by an arrow 24 in FIG. 2A, the pixels are processed one pixel at a time from the upper left pixel to the right of the image. Will end at the bottom right of.

In the present embodiment, a black and white image such as the document information 21 is converted into coded image information and stored in the image information storage device 5 as in the conventional binarized image coding process. Here, as shown in FIG. 2B, the color image 22 is 1
A pixel is represented by color information composed of a 3-byte RGB code, for example. The color area information specifying device 4 detects a color image area (which is the color image 22 in this embodiment) from the input image information, generates color area information, and sets it in the encoding device 3 (step S2). .

As for the color area information, the color image 22 is divided into color areas of two colors, and the start of each color area (position where color change occurs)
And coordinate information indicating the range of the area (corresponding to size and shape) and color information.

The encoding device 3 determines whether or not the pixel of the input image information is the start of color change based on the set color area information (step S3). As shown in FIG. 2A, when the determination result is the pixel 25 of the background (blue color image 22b) of the color image 22, the encoding device 3 determines the color information (blue) of the color image 22b. A process of converting into binary image information is executed (step S
4 YES, S5).

That is, as shown in FIG. 2B, color information (blue) consisting of a 3-byte RGB code is set to, for example, "0".
To a binary code. In this embodiment, the red color image 22a which is the character string of "title" is "1".
Is converted into a binary code.

The encoding device 3 encodes the converted binary image information by a predetermined binary image encoding method similarly to the monochrome image (21) (step S6). At the time of this encoding processing, the encoding information obtained by encoding the color area information is added. As shown in FIG. 2B, this coding information includes an identification code 30 indicating a color change and information 31 indicating a color area (color and range). The identification code 30 is, for example, JPEG.
This corresponds to the marker code of (color still image compression standard).

The encoding device 3 repeats the above encoding process up to the final pixel, and adds the encoded image information of the monochrome image and the encoded image information of the color area information corresponding to the color image 22 to the encoded image information. The image is stored in the image information storage device 5 (steps S7 to S8).

Here, in the coded image information corresponding to the color image 22, when the background blue changes to the red pixel of the "title" character string, the identification code 30 and the color area (color The coding information of the color area information including the information indicating the range) is added. (Decoding Process) Next, the decoding process of this embodiment will be described with reference to the flowchart of FIG.

First, encoded image information is taken out from the image information storage device 5 and input to the decoding processing device 6 (step S10). In the decoding processing device 6, the color region information analysis device 8 analyzes the color region information in the encoded image information, and outputs information regarding the contents (color and range) to the decoding device 7 (step S11). . The decoding device 7 temporarily stores the analyzed color area information (step S1).
2).

The decoding device 7 determines whether or not the coded image information corresponds to the color change position of the image based on the color area information (step S13). The judgment result is shown in FIG.
In the case of the pixel 25 of the background of the color image 22 (blue color image 22b) as shown in FIG.
The binarized information (encoded information) is switched to the color information (here, blue encoded information) stored as color area information (YES in step S14, S15).

The decoding device 7 decodes the switched coding information, restores the original image information of the color image 22 and outputs it to the image output device 9 (steps S16 and S17). Here, in the coded image information corresponding to the color image 22, in the case of the pixel of the red color image 22a of the “title” character string, the binarized information (coded information) is converted to the red coded information. Switch and decrypt. In the case of coded image information corresponding to a monochrome image, it is directly decoded into image information corresponding to the original monochrome image.

In this embodiment, the method of adding the coded information of the color area information to the beginning of the coded image information corresponding to the color image has been described, but the color information of the color area information (which indicates the color of the pixel is shown. It is also possible to encode only (information) in a fixed format and add it in pixel units where color change occurs.

Specifically, in the color image 22 of the text image shown in FIG. 2A, a pixel (for example, pixel 25) whose color changes from white or black to blue or red, or blue or red to white or black. This is a method of adding color coding information to a pixel (for example, pixel 26) that changes to.

With such a system, the decoding device 7 of this embodiment does not need to temporarily store the color area information, and the color coded information appears in the coded image information every time. Then, the coded image information may be switched to the color information.

As described above, according to the present embodiment, most of the image is a black-and-white image such as text information, and when performing image processing such as a text image partially including a color image, the color image is converted into a black-and-white image. It is encoded by the same binary image encoding method as. Therefore, it is possible to significantly reduce the information amount of the coded image information as compared with the coding process by the image coding method for color images. Also, the processing speed of the encoding process can be increased.

In the encoding process of the color image, since the encoding information of the color area information for identifying the color image is added to the encoded image information, the original image of the decoding process of the encoded image information is surely performed. You can revert to a color image.

Therefore, particularly in the image processing of a text image or the like partially including a color image, by adopting a binary image encoding method exhibiting a high compression rate, the information amount of the encoded image information corresponding to the color image can be obtained. As a result, the efficiency of the compression processing of the image information can be improved.

[0034]

As described above in detail, according to the present invention, particularly in a system for processing image information in which a black-and-white image and a color image are mixed, a high image compression rate including a partial color image can be obtained. Image encoding using the value image encoding method can be realized. Therefore, the amount of encoded images of color images can be reduced, and as a result, the efficiency of color image compression processing can be improved, so that the efficiency of image processing can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of an image processing system according to an embodiment of the present invention.

FIG. 2A is a diagram showing an example of a text image related to image processing of this embodiment, and FIG. 2B is a conceptual diagram showing encoded image information of color image information of this embodiment.

FIG. 3 is a flowchart for explaining an encoding process of this embodiment.

FIG. 4 is a flowchart for explaining a decoding process according to the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image input device, 2 ... Encoding processing device, 3 ... Encoding device, 4 ... Color area information designation device, 5 ... Image information storage device,
6 ... Decoding processing device, 7 ... Decoding device, 8 ... Color area information analysis device, 9 ... Image output device.

Claims (7)

[Claims] 1. An image input unit for inputting a color image, a conversion unit for converting the color image information input by the image input unit into binarized image information, and the binarized image information having a predetermined number of 2. It is characterized by further comprising: an encoding means for encoding by the value image encoding method; and a decoding means for decoding the encoded image information encoded by the encoding means into the original color image information. Image processing system. 2. An image input unit for inputting a binarized image or a color image; color image information is detected from the image information input by the image input unit; and color information designated in advance and the binarized image are detected. Conversion means for converting the color image information into binarized image information based on the relationship with information; binarized image information input by the image input means or the binarized image converted by the conversion means Coding means for coding information by a predetermined binary image coding method, and decoding the coded image information coded by the coding means into original binary image information or original color image information. An image processing system, comprising: 3. An image input unit for inputting a binarized image or a color image, and dividing the color image into color regions of two different colors, and associating the divided color regions with the binarized image information. Specifying means for specifying the color area information, and color image information in the image information input by the image input means is converted into binarized image information based on the color area information specified by the specifying means. A conversion unit and the binary image information input by the image input unit or the binary image information converted by the conversion unit is encoded by a predetermined binary image encoding method to correspond to the color image information. Encoding means for adding encoded information indicating a color region of a color image to the encoded image information, and the encoded image information encoded by the encoding means as original binary image information or original The image processing system being characterized in that; and a decoding means for decoding the color image information. 4. An image input unit for inputting a color image, and color region information for dividing the color image into color regions of different two colors and associating the divided color regions with binarized image information. Specifying means for specifying, and color image information input by the image input means,
2 based on the color area information designated by the designation means
Conversion means for converting into binary image information; and an identification code for identifying the color area of a color image by encoding the binary image information converted by the conversion means by a predetermined binary image encoding method. The image forming apparatus includes an encoding unit that adds encoded information indicating a color region to the encoded image information, and a decoding unit that decodes the encoded image information encoded by the encoding unit into original color image information. An image processing system characterized by the above. 5. A color image processing method applied to an image processing system that encodes a binary image by a predetermined encoding method and decodes the encoded image information that has been encoded into original binary image information. A step of detecting color image information from the input image information and converting the color image information into binarized image information based on a relationship between prespecified color information and binarized image information And a step of encoding the converted binary image information by a predetermined binary image encoding method, and a step of decoding the encoded image information into original color image information. And a color image processing method. 6. A binary image is encoded by a predetermined binary image encoding method, and the encoded image information encoded is used as the original binary image.
A color image processing method applied to an image processing system for decoding into binarized image information, comprising the steps of inputting a binarized image or a color image, dividing the color image into two different color regions, and Inputting color area information for associating the divided color areas with binarized image information; converting color image information into binarized image information based on the designated color area information; The encoded binary image information or the transformed binary image information is encoded by a predetermined encoding method, and the encoded image information corresponding to the color image information is added with the encoding information indicating the color area of the color image. And a step of decoding the coded coded image information into the original binarized image information or the original color image information. 7. A binary image is encoded by a predetermined binary image encoding method, and the encoded image information encoded is used as the original binary image.
A color image processing method applied to an image processing system for decoding into binarized image information, comprising the steps of inputting a color image, dividing the color image into two different color regions, and dividing the divided color regions. Specifying color area information for associating with the binarized image information, converting the input color image information into binarized image information based on the specified color area information, Encoding the binarized image information thus generated by a predetermined encoding method, and adding an identification code for identifying a color region of a color image and encoding information indicating the color region to the encoded image information; And a step of decoding the coded encoded image information into original color image information.