JPS61112282A - Image processing system - Google Patents

Abstract

PURPOSE:To increase the image compressibility regardless of the coding direction of an original and to attain the run length coding with high efficiency, by using an image turning means which reads out the image signal and turns it in a prescribed direction. CONSTITUTION:When the image data is turned, a CPU 22 writes successively the bit data of X and Y directions to a page memory P1 of an RAM 24 for the image data read by an original reader 2. Then the CPU 22 reads the 0-th data out of the memory P1 to a turning circuit 26 and then writes successively the data on the following addresses after writing each bit data to a page mem ory P2. The operations are carried out with a single piece of image data. Thus the coding direction is turned by 90 deg.. This can increase the image compressibility regardless of the coding direction of an original.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing system that compresses and expands image information read by an image reading means.

[Prior art and its problems]

Image data obtained by digitizing image information has a large bias in the distribution of data values depending on the characteristics of the image data forming each image data.For example, in facsimile images, characters are usually printed on a white background. and figures are drawn, so facsimile data (black and white binary) has an overwhelmingly large proportion of data values corresponding to "white".

As an encoding method that realizes data compression by utilizing such data bias, there is a conventionally well-known run length (hereinafter referred to as RL) encoding method. This method compresses data by representing a series of identical data (this is called a run) with a code that represents its data value and the number of data included in the 70 runs (this is called RL or run length). It is something to do.

In conventional devices, the operation of the RL encoding method is as follows.

First, when the data to be encoded is input sequentially, the data value is detected, and if the detection result is the same as the previous data value, the count value of the run length up to that point is changed (counted up). If the value is not the same as the previous data value, the run is considered to have ended, and a codeword is created based on the run length count up to that point, and the codeword is output and the first codeword corresponding to the start of a new run is generated. A run length count is performed.

As shown in Figure 1(a), this encoding method is effective when the direction of a white background or ruled line matches the encoding direction, as the same data is continuous, increasing the compression rate. When the encoding direction intersects with the ruled line direction as shown in FIG. 2B, different data appear alternately, resulting in a significant reduction in the compression rate.

In general, documents, documents, etc. have both vertical and horizontal writing, and even for the same document, depending on the encoding direction, the compression rate will decrease, which is extremely bad.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and includes a rotation command means for rotating an image signal stored in a signal storage means in a predetermined direction, and a rotation command means for rotating an image signal stored in a signal storage means in a predetermined direction. An object of the present invention is to provide an image processing system that can increase the image compression rate and efficiently perform RL encoding regardless of the encoding direction of a document by providing an image rotation means that reads out an image signal and rotates it in a predetermined direction. shall be.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is an external connection diagram of an image processing system to which the present invention is applied. 1 is an internal memory consisting of a microcomputer for system control, RAM, ROM, etc., and an external memory consisting of a floppy disk or cartridge disk. Control unit (workstation) with memory
2 is a manuscript league that converts document information of a manuscript placed on a manuscript table in the input section of a digital copying machine into an electric signal using an image sensor such as a COD, and is a manuscript league according to the present invention. This serves as an image reading means. Reference numeral 3 denotes a high-speed printer, such as a laser beam printer, which records an image on a recording material based on information converted into an electrical signal at the output section of the digital copying machine. Reference numeral 4 denotes an image file having a recording medium such as an optical disk or a magneto-optical disk, in which a large amount of image information can be written and read, and constitutes the image storage means of the present invention. Reference numeral 5 denotes a CRT device that displays image information photoelectrically read by a digital copying machine input scanner (reader) or system control information.

Cables 6 to 9 electrically connect each input/output device. Reference numeral 1o denotes a keyboard provided in the control section 1, and by operating this keyboard 1o, system operation commands, etc. are issued.

Reference numeral 11 denotes an operation panel for issuing operation commands for the digital copying machine, and includes setting keys for the number of copies, copy magnification, etc., a copy key 12 for instructing the start of copying, a numerical display, and the like. Reference numeral 13 denotes a mode changeover switch which constitutes a rotation command means for instructing a request to rotate the image read by the document reader 2, and when the mode changeover switch 13 is pressed, a rotation mode is set. Reference numerals 14 and 15 denote indicators composed of light emitting diodes (LEDs) for displaying the selected mode (one rotation pass) of the mode selector switch 13.

FIG. 3 is a block diagram showing the circuit configuration of the image processing system shown in FIG. 2. Each block corresponding to that in FIG. 2 is given the same number as in FIG. First, each block within the control section 1 will be explained.

Reference numeral 21 denotes a keyboard, which corresponds to the keyboard 1Q shown in FIG. Reference numeral 22 denotes a central processing unit (CPU) consisting of a microcomputer, which also serves as the rotational image writing command means of the present invention. 23 is ROM
(read-on memory) in which a system control program is written in advance, and the CPU 22 performs control operations according to the program written in the ROM 23. 24 is a RAM (random access memory), which is mainly used as a working memory of the CPU 22 and a page memory for storing image data exchanged between each input/output unit. The page memories are capable of storing one screen of information that can be displayed on the CRT device 5, and two page memories, P, , P2, are prepared, and can store image information for two screens in total. This page memory P,
, P2 constitute the signal storage means of this invention. 2
5 is an external memory consisting of a floppy disk,
System control programs and the like are stored. Reference numeral 26 denotes a rotation circuit constituting the image rotation means of the present invention, which rotates the image data by 90'. Reference numeral 27 denotes an input/output interface for achieving information exchange between the control section 1, document reader 2, and high-speed printer 3. Reference numeral 28 denotes a companding circuit constituting the image companding means of the present invention, which compresses and decompresses data using the above-mentioned RL encoding method. 29 is an optical disk interface for exchanging information with the image file 4, and 30 is a CRT interface for exchanging information with the CRT device 8. 31 is a 16-bit bus,
Signal transfer between each block within the control unit 1 is performed. 6-9
As mentioned above, is a cable that electrically connects each input/output device, and transmits control signals and image signals. Note that the arrows on the cables indicate the flow of image signals. Also, the flow of control signals is bidirectional in the cable.

Next, the image data transfer recording and reading operations will be described with reference to the flowcharts shown in FIGS. 4 and 5. In addition, (1) to (8) and (11) to (18)
represents each step.

First, transfer and recording of image data will be explained.

An instruction to input an image is input to the document reader 2 by operating the board 21 of the workstation 1 (1). Upon receiving this instruction, the document reader 2 starts transferring the read image data (digital signal) to the page memory P in the RAM 24 of the workstation 1 (2). Next, C
PU22 has 7 mode keys, 3 keys, and uni. 3) If the mode changeover switch 13 is pressed, the image data stored in the page memory PL is read out to the rotation circuit 26, and the image data is rotated to 90'. The image data is rotated and sequentially stored in the page memory P2 (4), and if the mode changeover switch 13 is not pressed, the image data stored in the page memory PI is simply stored sequentially in the page memory P2 without being rotated. Go (5). Next, the image data stored in the page memory P2 is read out and transferred to the companding circuit 28 according to a command from the CPU 22 (6), and predetermined data compression is executed (7). A flag indicating the presence or absence of image inversion is added to the image file 4 and stored <(8).

When reading the image data stored in the image file 4, it is executed according to the flow shown in FIG.
A command to read image data is input by operating the keyboard 21 of the workstation 1 (11). Then CP
The U22 sends an image transfer command to the image file 4, transfers the read image data to the companding circuit 28 (12), and expands the image data at a predetermined magnification (13). Next, the expanded image data is transferred to the page memory P2 (14). At that time, check whether the image data is rotated in step (4) in FIG. 4 or not.
The CPU 22 makes a judgment based on the flag indicating the presence or absence of rotation added in step 8), and if the image data is rotated (step 15), the image data stored in the page memory P2 is transferred to the rotation circuit 2.
6 is rotated by 90 degrees opposite to the direction of rotation in step (4) of FIG. 4 and transferred to the page memory P1 (1
6). On the other hand, if it is determined in step (15) that the image data is not rotated, the image data stored in the page memory P2 is not rotated and is simply transferred to the page memory PI.
are sequentially stored in (17). Subsequently, the contents of the page memory P1 are transferred to the high-speed printer 3 in accordance with instructions from the CPU 22.
(18).

Next, the image data rotation operation will be explained with reference to FIGS. 6(a) and 6(b). Note that an example is shown in which the image data stored in the page memory P1 is rotated by 90 degrees and stored in the page memory P2.

As shown in FIG. 6(a), the CPU 22 stores the image data read by the document reader 2 in the page memory P of the RAM 24 by 16 bits in the X direction and 1 bit in the X direction. Write bits one by one. When this write operation is completed for one image,
The CPU 22 reads out the 0th 16-bit data (O to ts) in the X direction and the 0th 1-bit data in the X direction from the page memory P1 on the RAM 24 to the rotation circuit 26, as shown in FIG. 6(b). Each bit data is stored in the page memory P2 as the 0th 1 bit in the X direction.

Write 0 to the 0th 16 bits in the X direction, then
The CPU 22 reads the first 16-bit data (16 to 3i) in the X direction from the page memory P on the RAM 24, and the first 16 bit data in the X direction.
The sixth 1-bit data is read out to the rotation circuit 26, and the sixth one bit data is read out to the rotation circuit 26.
As shown in Figure (b), each bit data is stored in the page memory P2 as follows:
Write to 6-bit. By performing this operation on one image data stored in the page memory P1 of the RAM 24, image data in which the image information whose encoding direction was vertical is corrected in the horizontal direction is sequentially written to the page memory P2. , Hereafter, this operation will be performed as page memory P
By applying this to the entire area of I, image data rotated by 90 degrees is stored in the page memory P2.

In the above embodiment, the image rotation command means is provided in the document reader 2, but the keyboard 21 on the workstation 1 side
It may be configured to allow more rotation commands. Alternatively, it is also possible to determine whether the text is written horizontally or vertically based on the reading signal, and give a rotation command according to this determination.

〔Effect of the invention〕

As explained above, the present invention includes a rotation command means for rotating an image signal stored in a signal storage means in a predetermined direction;
In response to the rotation command from the rotation command means, the image signal stored in the signal storage means is read out. 0.
□, 4. Therefore, the image compression rate can be increased regardless of the encoding direction of the document, and the RL encoding can be efficiently executed.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are diagrams for explaining the encoding method, Figure 2 is an external connection diagram of an image processing system to which this invention is applied, and Figure 3 is the image processing shown in Figure 2. FIGS. 4 and 5 are block diagrams showing the circuit configuration of the system, FIGS. 4 and 5 are flowcharts for explaining image data transfer recording and reading operations, and FIG. 6 is a diagram for explaining image data rotation operations. In the figure, 1 is a control unit, 2 is a document reader, 3 is a high-speed printer, 4 is an image file, and 5 is a CRT device. 6 to 9 are cables, 10 is a keyboard, 11 is an operation panel, 12 is a copy key, 13 is a mode changeover switch, 1
4.15 is a display, 21 is a keyboard, 22 is a CPU,
23 is ROM, 24 is RAM, 25 is external memory, 26
is a rotation circuit, 27 is an input/output interface, 28 is a companding circuit, 29 is an optical disk interface, and 30 is a C
RT interface, 31 is a path. Figure 1 (a) (b) 2nd diagram Figure 3 1 j 4
':) Figure 4 Figure 52

Claims (1)

[Claims] An image reading means for converting and reading an image into a digital signal, a signal storage means for temporarily storing the image signal read by the image reading means, and an image companding means for compressing the image signal stored in the signal storage means. An image processing system comprising: rotation command means for rotating the image signal stored in the signal storage means in a predetermined direction; and rotation command means for rotating the image signal stored in the signal storage means in response to a rotation command from the rotation command means. An image processing system comprising: an image rotation means for reading and rotating an image in a predetermined direction.