JPS61133778A - Two dimensional encoding line restoring method - Google Patents

Abstract

PURPOSE:To facilitate restoring of two dimensional encoding and to minimize the peripheral circuit by retaining the information of reference line as an inter- mediate data composed of simple color information and bit length information and by administering correspondence of a position on a reference line and a present position on an encoding line by the address of intermediate buffer and the displacement inside the address. CONSTITUTION:When it is one dimensional code (MH), a microprocessor 5 transfers it to a run-length convertion 3. In case of two dimensional code (MR), it is developed to black and white color information and bit length information for each mode. A pair of data composed of one color information of intermediate data and a bit length information uses the memory capacity of teo bytes. Uppermost bit of upper byte out of the two tytes is the color information C, denoting black when it is logical 1, and white when it is logical 0. When the decoding starts from the left edge of the scanning line, the position on the reference line corresponding with starting point picture element a0 is administered by an address A0 of intermediate bufffer and the displacement d0 inside the intermediate data. Namely, the present position on the reference line is administered by coordinates (A0, d0).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method used in 7A/7mm transmission, etc., for restoring a two-dimensional encoded line to black and white bit data.

[Prior art]

Conventionally, a two-dimensional code (MR code) line defined in the 03 facsimile standard has been restored using the method shown in FIG. In the one-dimensional encoded line inserted every K lines, scanning line information is sent in the form of a one-dimensional code (MH code), so it can be restored relatively easily. (In the G3 standard, the values of K are determined to be 2 and 4.) The MH code of the one-dimensional encoded line of the reception code buffer 1 is processed by the MH/MR decoder 2 as color information (black/white),
The data is decoded into bit length information, and further converted into a dot or white bit string by a run length decoder 3 and held in a scanning line buffer 4.

On the other hand, when two-dimensional encoding is being performed, two steps must be taken to restore every single line.

First, the MH/MR decoder 2 decomposes one scanning line of scan coded data into horizontal mode, pass mode, etc. Next, using the control unit 5, the scanning line information of one scanning line before the previous scanning line in the scanning line buffer 4 is searched in order from the left end of the scanning line to find a color change point, and by referring to the change point, the current The scanning line is restored to bit slim data from the horizontal mode, vertical mode, pass mode, etc. decoded by the M)i/MR decoder 2. The bit data of the restored scanning line is held in the scanning line buffer 4.

Therefore, the conventional method has circuits for restoring Ml (code) and restoring MR code, and also has black and white bits as scanning line information (reference line information) for the scanning line immediately before the scanning line to be restored. Since it only has image data, the only options are to search over a wide area to find the pixel change point, or to memorize the change point location in the form of the position from the left end of the scanning line, which is constructed using I hardware. To do this, the amount of hardware increases, and it takes a lot of processing time to control the program to the processor.

[Purpose of the invention]

The purpose of the present invention is to change the form of the reference line when attempting to restore a two-dimensional encoded line to only the minimum color information and bit length data, instead of referring to a bit image in a completely restored state as in the past. The present invention aims to provide a two-dimensional encoded line restoration method that can reduce peripheral hardware by constructing an intermediate buffer and leaving it in a form that is easy to process by a microprocessor.

[Structure of the invention]

The two-dimensional encoded line restoration method of the present invention includes a microprocessor, its control program, a decoder for restoring the two-dimensional code, and a memory portion that stores the form of the reference line as color information and bit length information. However, instead of having the form of the reference line required when restoring the two-dimensional code as the final form (bit image of the scanning line), it has an intermediate buffer that holds the color information and bit length information, and the current The special feature is that when restoring a two-dimensional encoded line, the contents of this intermediate buffer are referred to to perform the restoration at high speed.

[Principle and action]

In addition to restoring a two-dimensional code, the present invention retains information on a reference line as intermediate data consisting of simple color information and bit length information, and connects the position on the reference line and the current position on the encoded line. This method attempts to facilitate two-dimensional code restoration by managing correspondence between intermediate buffer addresses and displacements within the addresses.

〔Example〕

Next, an embodiment of the present invention will be described using FIG. 2.

This circuit operates under the control of the microprocessor 5,
The circuit configuration is divided into 5 blocks, and the compressed code (
MH/MR code) is stored in the reception code buffer 1, and the reference scanning line encoded with the MH code is restored to color information and bit length information, and two-dimensionally encoded scanning lines other than the reference scanning line are stored. M) i/MR decoder 2 for restoring to three modes: horizontal mode, vertical mode, and pass mode;
An intermediate buffer 6 that stores two-dimensional codes (MR codes) as color information and bit length information, a run length converter 3 that develops black and white color information and bit length information into a complete scanning line bit image, and a scanning line It consists of a scanning line buffer 4 for storing bit images.

The microprocessor 5 sequentially outputs a one-dimensional or two-dimensional compressed code from the received code buffer 1, and outputs the MH/M
The R decoder 2 is set and a decoding command is issued. M) The i/MR decoder 2 decodes into bit length information if it is an MH code, and into pass mode if it is an MR code.
Decode into each mode such as horizontal mode and vertical mode,
Transfer to microprocessor 5.

FIGS. 5(a) and 5(b) show the output format of the M)l/MR decoder 2. FIG. 5(a) shows the output format of the MH decoder. The output result is shown in 16 bits, of which 12 bits from bit o (bo) to bit 11 (bll)
The bit length (bit length) of the same color is expressed in bits.

FIG. 5(b) shows the output format of the MR decoder. The output result is also shown as 16 pits, bits 9 (bo) to
Bit 11 (bll) indicates the pass mode, vertical mode, or horizontal mode, and bit o (bo
) to bit 9 (b9) indicate the relative distance L2 of the changed pixel in the vertical mode.

If it is an MH code, the microprocessor 5 transfers it to the run length converter 3 as is. In the case of MR code, it is developed into black and white color information and bit length information according to the following procedure for each mode.

Since the encoded line inserted every K lines is sent as a one-dimensional code, this is decompressed into bit length information by the M)l/MR decoder 2, and the short result is first sent to the intermediate buffer 6 as intermediate data. It can be stored.

The structure of the intermediate data is shown in FIG. A pair of data consisting of one color information and one pit length information uses 2 bytes of memory capacity. Among the two bytes, the most significant bit in the upper one byte is color information C, with logic 1 being black and logic O being white. The remaining 15 bits are shown. Addresses A o = A n of the intermediate buffer correspond to positions within the scanning line, with the lowest address A□ corresponding to the leftmost end (starting end), and increasing addresses toward the right end (ending end). Corresponds to the position moved to the painful gyrus).

When starting decoding from the scanning line omission, the starting pixel a
o (the position on the reference line corresponding to the currently restored position [1] on the encoded line is set to the address A of the intermediate buffer)
0 and the displacement d within the intermediate data.

Manage with. In other words, the current position on the reference line is the coordinate (
Ao, do). The value of do can have a positive or negative sign. If it is negative, the starting pixel position is included in Ao, and if it is positive, the starting pixel is the address before A. This is the case if it is included in On the other hand, as the position on the encoding line, the displacement D0 from the starting point within the same pixel including the starting pixel will be managed.

To explain the definition of the pass mode using FIG. 4(a), a change in color I [! The iI index is a changed pixel b1 on the reference line, indicating that the next changed pixel on the encoded line has not yet been detected. Therefore, if the detection position of the pass mode is set to X, the value that must be found is ao
The displacement will be from to X. Since the value of DOIdo is known at the preprocessing stage, a.

Displacement from to X, w 11 j−”1
(X-ao) is 1(bt-bo)+do+z(b,-
bt). (Do in this case has a negative value) When Do, do, and Ao are updated for arrow decoding, Do'=D6+J (X ao) *
do=OsAo'''Az. Also, since no missing pixel change point is found, the value of D0' cannot be intermediate data.

To describe the definition of the horizontal mode using (in Fig. 4), the displacement 1 (al-ao) between the starting pixel a0 on the encoding line and the next change pixel a1, and the next change pixel a! This is a mode in which the displacement i (a2-a, ) up to is given by the MH code. Therefore, J(at-ao)-1(
The value of at "I) can be obtained by decoding the horizontal shade.Then, the length of the white pixel of the encoded line is Do+A!(a+-ao)+The length of the black pixel is 1(a2-al ).This value is also used as intermediate data to report the running distance of the running hill, and is also sent to the run length converter 4 with color information attached.

The next starting pixel moves to position a2, so Dos(
lcbr-bo)+1Cbt-bs)+...1(bN
-')N-1))-1-ao(l(at-ao)+1(
at −as) ) + Ao'=AN. The value of N is calculated by adding 1 (bN-bN-□) until 'O becomes a positive value.

To explain the definition of the vertical mode using @4 Figure (C), it is a mode that gives a relative distance of 1 (bs-at) between the changed pixel a on the reference line and the changed pixel a1 on the encoded line. l(b, -at) in the figure is obtained from the MH/MR decoder 2 during vertical mode decoding. 1(
al-ao), J(at ”o)=lcbx
-bo)+do+A! (bt-as) and lcl(bs
``s) is given as a negative value).The encoded line Q white run length is Do + A! (a + ``o), so Do
+1(bt-bo)+do+1(bt-at) becomes the data given to the run length converter 4, and is also stored in the intermediate/<tufa as reference data for the next scanning line.
t,>o, aO,aOtWhen updating person G, D0
'=Oe dO'= l (bs -a+) s a
o'=al + Ao'=A1.

As mentioned above, the variable do on the intermediate buffer.

By managing the values of Ao and the variable Do on the current encoded line, the bit length for restoring the encoded line can be obtained with a simple calculation. Regarding color information, it can be easily determined because the colors after horizontal mode and vertical mode are reversed, and the colors after pass mode are not reversed.

M) By setting the color information and bit length information obtained by the i/MR decoder 2 and the microprocessor program in the run length converter 3, it is converted into a white or swallow bit string and stored in the scanning line buffer 4. @ goes up with scanning line image.

The restoration speed of this method is largely determined by the performance of the microprocessor used, so by using a high-performance, high-speed 16-bit microprocessor, it is possible to achieve almost the same speed as the conventional method. .

〔Effect of the invention〕

According to the present invention, as explained above, when restoring a two-dimensional code, the reference line groove structure is provided in the form of an intermediate buffer that can easily be processed by a microprocessor, thereby reducing the number of peripheral circuits to an order of magnitude. be able to.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the conventional system, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a block diagram showing the contents of the intermediate buffer in Fig. 2, and Fig. 4 2 is a timing chart showing the operation of FIG. 2, and FIG. 5 is a configuration diagram showing the output formats of the MH decoder and MR decoder in FIG. 2. 1...-9 signals = r-)' buffer, 2...
MH/MR decoder, 3... Run length converter, 4...-* scan line buffer, 5... Control 61
ffls, 6... intermediate buffer, An...
...Intermediate buffer address, C...--Intermediate data color information, L...Pixel bit length information, bn
...Pixel change point on the reference line, aG...
...Start pixel, afi... Change point of a pixel on the encoding line, do ...Displacement to the start pixel within the same pixel including the start pixel on the reference line, Do
...Displacement to the starting pixel within the same pixel including the starting pixel on the encoding line, 1 (bN bN-t)...
...displacement of bN and bN-1 darkness on the line, Ag z
Al...Reference line address, X...
Starting pixel position for long decoding, Ll...-Bit length data when outputting MH code, L2...Displacement amount during vertical mode decoding, M...When outputting MR code Mode information. Hayabusa! Figure 3 Kionson 4 Figure R side

Claims (1)

[Claims] It has a microprocessor, a decoder for restoring the two-dimensional code, and a memory part for temporarily storing received data and intermediate data, and converts the two-dimensional code used when transmitting the image into a black and white bit string. When restoring, the bit image is stored in an intermediate buffer as intermediate data expressed by color information (black/white) and run length, and when restoring the current scan line, the process uses the intermediate data of the previous scan line to restore the current scan line. A two-dimensional encoded line restoration method characterized by restoring scanning lines.