JP2001119566A - Compression reproduction method for multilevel image data, and image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compression reproduction method for multilevel image data that can adopt a conventional coding/decoding section compatible with binary processing by decomposing multilevel image data for every bit and composing corresponding bits, thereby decomposing the multilevel image data into a plurality of layers of binary image data. SOLUTION: The multilevel image data are decomposed for every bit and the corresponding bits are composed to process the multilevel image data into a plurality of layers of the binary image data, then a plurality of layers of the binary image data is encoded and stored in an image memory 14. Furthermore, a plurality of layers of the binary image data stored in the image memory 14 is decoded and corresponding bits of the binary image data of the respective layers are sequentially synthesized to reproduce the multilevel image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression / reproduction method for decomposing multi-valued image data for each bit, synthesizing corresponding bits, and decomposing the binary image data into a plurality of layers of binary image data. The image processing apparatus according to the present invention is suitably used for a digital multifunction peripheral.

[0002]

2. Description of the Related Art Recently, digital multifunction peripherals in which a facsimile machine is combined with a copy machine have been widely used. A plurality of original images received by a facsimile with this kind of digital multifunction peripheral are output or read by a scanner. After temporarily storing the original image in the image memory for memory transmission,
In the case of multi-copying, there is a problem that a sufficient image quality cannot be obtained with a normal binarized image.

[0003]

However, when a multi-valued image is printed out with high image quality or displayed on a monitor or the like, a large-capacity image enough to store the multi-valued image is required. A memory is required, and the encoding processing circuit cannot handle the conventional binarization processing, resulting in an increase in size and cost of the image processing apparatus.

The present invention has been made in consideration of the above circumstances, and decomposes multi-valued image data bit by bit, synthesizes corresponding bits and decomposes them into binary image data of a plurality of layers. Accordingly, it is an object of the present invention to provide a method of compressing and reproducing multi-valued image data which can be used as it is by a conventional encoding / decoding unit which supports binary processing, and an image processing apparatus which can execute this method. I have.

[0005]

According to a first aspect of the present invention, there is provided a method for compressing and reproducing multi-valued image data, comprising the steps of: The bits to be processed are combined to be processed into binary image data of a plurality of layers, the binary image data of the plurality of layers are encoded and stored in the image memory, and the binary image data of the plurality of layers stored in the image memory are further encoded. After decoding the value image data, the corresponding bits of the binary image data of each layer are sequentially combined to reproduce the multi-value image data.

In the image processing apparatus according to the present invention, a multi-valued image data decomposing unit for decomposing multi-valued image data bit by bit, synthesizing corresponding bits and processing into binary image data of a plurality of layers, An encoding / decoding unit that encodes and decodes binary image data decomposed into a plurality of layers, an image memory that stores encoded binary image data of a plurality of layers, and a decoded plurality of layers And a binary image data combining unit for sequentially combining corresponding bits of the binary image data.

According to a third aspect of the present invention, the image memory has an area for storing binary image data processed into a plurality of layers in units of one frame or one page.

[0008]

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

First, a method for compressing and reproducing multivalued image data according to the present invention will be described.

FIG. 2 shows multi-valued image data for one line (here, 2 bits).
n is composed of 2-bit data (X1 to n, Y1 to n). Here, each of bits X1 to n and Y1 to n of data (X1 to n, Y1 to n) is defined by “1” or “0”.

In the method of the present invention, such multi-valued image data is decomposed into bits for each pixel, bits corresponding to each pixel are combined and processed into binary image data of a plurality of layers. I have.

Hereinafter, the method of the present invention will be described with reference to the flowchart of FIG.

The multivalued image data (2 bits in FIG. 2) read by a scanner or the like includes bits X1 to Xn and Y1 to Y
n, that is, as shown in FIG. 3, the front data X
1 to Xn to generate binary image data of the first layer,
Also, post-data Y1 to Yn of each pixel P1 to Pn.
To generate binary image data of the second layer (10
0).

The binary image data of two layers generated in this manner is encoded according to an encoding method such as MR, MH, MR, JBIG (101), and the encoded image data of each layer is sequentially stored in an image memory. (To be described later) (10
2).

Then, the image data of each layer stored in the image memory in this way is decoded (103), and corresponding bits are sequentially combined with each other for each decoded layer (104), as shown in FIG. Such 2-bit multi-valued image data is reproduced.

In this case, the multi-valued image data is 2
Although multi-valued image data of bits has been described as an example, the present invention is not limited to this example, and can be applied to multi-valued image data of 3 bits or more.

Next, an image processing apparatus capable of implementing such a method of compressing and reproducing multi-valued image data will be described.

FIG. 4 shows an example of the main configuration of the image processing apparatus of the present invention.

Here, as the image processing apparatus 1,
Although the configuration of the digital multi-function peripheral is shown, the present invention is not limited to this example. For example, a so-called multi-copy apparatus that encodes image data, temporarily stores the image data in an image memory, and decodes and records the encoded image data. Can also be applied.

The image processing apparatus 1 comprises a CPU and the like, and a main control section 10 for controlling the following sections; a scanner 1 for reading a set original and converting it into multi-valued image data.
1. A multi-valued image data decomposing unit 12 that decomposes each of the multi-valued image data for each bit, combines the corresponding bits, and processes the multi-valued image data into a plurality of layers of binary image data, Encoding / decoding unit 1 for encoding data and decoding the encoded multi-layer binary image data
3. Storing the encoded binary image data of a plurality of layers, the image memory 14 having two areas 14A and 14B, and sequentially combining corresponding bits of the decoded binary image data of the plurality of layers. A binary image data synthesizing unit 15,
A recording unit 16 for recording multi-valued image data on recording paper set in advance, an operation unit 17 including abbreviated dials and function keys, an NCU 18 for controlling connection to the telephone line L, various types of data necessary for facsimile communication And a modem 19 for modulating and demodulating a signal.

When the image processing apparatus 1 receives multi-value image data via the telephone line L, or reads an original with the scanner 11 and converts it into multi-value image data, the multi-value image data is processed according to the method described above. The recording is performed by the recording unit 16.

This will be described with reference to the flowchart of FIG.

That is, the image processing apparatus 1 uses the telephone line L
When multivalued image data (here, 2 bits) is received by the multivalued image data decomposing unit 12 as shown in FIG. Such two-level binary image data is processed (200), and of the processed two-level binary image data, the previous data (see FIG. 3) is stored in the area 14A of the image memory 14 (201). , After data (Fig. 3
) Is stored in the area 14B of the image memory 14 (202).

When the preceding data and the succeeding data are stored in each of the areas 14A and 14B for one page of the original, the binary image data stored in the areas 14A and 14B is encoded by the encoding / decoding unit 13. Encoding is performed in the order of the area 14A and the area 14B (203), and is sequentially stored in the image memory 14 (204).
Are decoded by the encoding / decoding unit 13 in order of the preceding data and the succeeding data (205), and among the decoded two-level binary image data, The previous data is stored in the area 14A of the image memory 14 (206), and the subsequent data is stored in the image memory 14.
(207).

When the preceding data and the succeeding data are stored in each of the areas 14A and 14B for one page of the document, the binary image data synthesizing section 15 stores the two layers of the two layers stored in each of the areas 14A and 14B. The binary image data of the pixels P1 to Pn corresponding to each layer is synthesized with the value image data (208), and is reproduced as 2-bit multivalued image data as shown in FIG. Record.

It should be noted that the recording unit 16 can be constituted by, for example, a laser printer. In this case, the multi-valued image data restored by the binary image data synthesizing unit 15 is converted into a predetermined VIDEO signal. You may make it output to an external monitor etc. At this time, the aforementioned area 1
In each of 4A and 14B, binary image data of each layer is stored for each frame.

Although only two areas are provided in the image memory 14 here, the present invention is not limited to this example, and three or more areas may be provided. In this way, multi-valued image data of 3 bits or more can be handled.

[0028]

As can be understood from the above description, in the method for compressing and reproducing multi-valued image data according to the first aspect of the present invention, after decomposing the multi-valued image data for each bit, Are combined to be processed into a plurality of layers of binary image data, the plurality of layers of binary image data are encoded and stored in an image memory, and further, a plurality of layers of binary image data stored in the image memory. After decoding the data, the multi-valued image data is reproduced by sequentially combining the corresponding bits of the binary image data of each layer, so that the multi-valued image data is It can be processed by the encoding / decoding processing circuit, preventing the device from being enlarged,
High cost can also be suppressed.

In the image processing apparatus according to the second aspect, a multi-valued image data decomposing unit that decomposes multi-valued image data bit by bit, synthesizes corresponding bits, and processes them into binary image data of a plurality of layers, An encoding / decoding unit that encodes and decodes binary image data decomposed into a plurality of layers, an image memory that stores encoded binary image data of a plurality of layers, and a decoded plurality of layers And a binary image data synthesizing unit for sequentially synthesizing the corresponding bits of the binary image data described above, so that the method according to claim 1 can be easily implemented.

In the image processing apparatus according to the third aspect, since the image memory has an area for storing binary image data processed into a plurality of layers for each frame or page, the image memory is stored in the area. The binary image data thus divided can be processed for each frame and each page.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a method for compressing and reproducing multivalued image data according to the present invention.

FIG. 2 is a diagram schematically showing multi-valued image data for one line.

FIG. 3 is a diagram schematically showing binary image data processed into a plurality of layers.

FIG. 4 is a diagram illustrating an example of a main configuration of an image processing apparatus according to the present invention.

FIG. 5 is a flowchart illustrating an example of a basic operation of the image processing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus 12 ... Multivalued image data decomposing part 13 ... Encoding / decoding part 14 ... Image memory 14A, 14B ... Area 15 ... Binary image data synthesizing part

Claims (3)

[Claims] 1. Multi-level image data is decomposed for each bit, corresponding bits are combined, processed into a plurality of layers of binary image data, and then a plurality of layers of binary image data are encoded. After decoding the binary image data of a plurality of layers stored in the image memory and decoding the corresponding bits of the binary image data of the respective layers sequentially, the multi-level A compression reproduction method for multi-valued image data that reproduces image data. 2. A multi-valued image data decomposer for decomposing multi-valued image data bit by bit, synthesizing corresponding bits and processing them into binary image data of a plurality of layers,
An encoding / decoding unit that encodes and decodes the value image data, an image memory that stores the encoded binary image data of a plurality of layers, and a corresponding one of the decoded binary image data of the plurality of layers. An image processing apparatus comprising: a binary image data synthesizing unit that sequentially synthesizes bits. 3. The image processing apparatus according to claim 2, wherein the image memory has an area for storing binary image data processed into a plurality of layers in units of one frame or one page.