JPH03210880A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To reduce a coded data quantity of a picture data with many change points by interrupting the coding according to the linear or 2-dimension coding system when a coded bit number of one line is increased and adopting the coding system independently of the quantity of production of change points of the picture. CONSTITUTION:When a value of a code length counter 13 exceeds a prescribed value, it is informed to a coding section 12 by using an excess signal 24. The coding section 12 outputs an unique mode start code representing a non-MR code to a bus for a coded code 16 and a code length 17. Then a coding stop signal 25 is used to apply succeeding coding to a serial parallel conversion section 14. Moreover, a byte pack section 15 selects the data input coded succeedingly from the coded code 16 and the code length 17 into the unique coding code (RM) 20 and its code length 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a facsimile device that encodes and transmits and receives image signals.

[Prior Art] Conventionally, image data transmitted and received by a facsimile machine is M H (Modified Huffman), M
R (Modified READ) or MMR (Modified
MR) is encoded using a coding method, etc., and then transmitted and received. Of these, the MH encoding method and the MR encoding method have been standardized as encoding methods in the G3 group,
The MMR encoding method is standardized as an encoding method in the G4 group.

[Problems to be Solved by the Invention] However, since these encoding methods such as MH and MR codes are basically run-length encoding, black-and-white Compression has little effect on image data in which changing points occur frequently (on the contrary, there is a problem that the amount of data increases up to about six times the original image data).

Therefore, such image data is
If the image data is encoded and transmitted, the amount of encoded data increases, so it takes a very long time, and a large capacity image memory is required to store the encoded image data. There is.

The present invention was made in view of the above-mentioned conventional example, and when the number of encoded bits for one line increases, it is possible to
The amount of encoded data for image data with many change points is reduced by interrupting the encoding according to the dimensional encoding method and using an encoding method that does not depend on the amount of change points in the image after that. The purpose is to provide a facsimile machine with

[Means for Solving the Problems] In order to achieve the above object, a facsimile apparatus of the present invention has the following configuration. In other words, it is a facsimile machine that compresses image data and transmits and receives it.
an encoding means for encoding by dimensional encoding or two-dimensional encoding; a determining means for determining whether the amount of code for one line encoded by the encoding means is equal to or greater than a predetermined amount; , when it is determined that the encoded code amount has exceeded the predetermined amount, the encoding by the encoding means is interrupted, and the image data is encoded by a different encoding method from the encoding means; and control means for controlling.

[Operation] In the above configuration, it is determined whether the number of coded lines of one line encoded by the encoding means that encodes image data by one-dimensional encoding or two-dimensional encoding exceeds a predetermined amount. When it is determined that the encoded code amount has exceeded a predetermined amount, the encoding unit interrupts encoding and operates to encode the image data using a different encoding method from that of the encoding unit. do.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Description of facsimile device (FIGS. 1 and 2)] FIG. 2 is a block diagram showing a schematic configuration of a facsimile device according to an embodiment.

In the figure, reference numeral 100 denotes a reading unit that photoelectrically reads an original and outputs it as a digital image signal to a control unit 101, and is equipped with an original conveyance motor, a CCD image sensor, and the like. 110 is a line memory for storing image data of each line of image data; when transmitting or copying a document, one line of image data from the reading section 100 is stored; when receiving image data, it is decoded; One line of received image data is stored. Image formation is then performed by outputting the stored data to the recording unit 102.

Reference numeral 111 denotes an encoding/decoding unit that encodes image information to be transmitted by MH encoding or the like, and decodes received encoded image data to convert it into image data. Further, 112 is a buffer memory that stores encoded image data that is transmitted or received. These control units 101
Each part includes a CPU 11 such as a microprocessor, for example.
3.

A recording unit 102 includes a thermal line head and records an image on thermal recording paper using a thermal recording method. 103 is a key for instructing various functions such as starting transmission, and a key for inputting a telephone number.
This is an operation section including the following.

A display section 104 is usually provided adjacent to the operation section 103 and is used to display various functions, the status of the device, and the like. 105 is a power supply unit for supplying power to the entire device. Further, 106 is a modem (modulator/demodulator), 107 is a network control unit (NCU) that performs automatic call receiving operation and line control operation by detecting readout sound, and 108 is a telephone set.

FIG. 1 is a block diagram showing a schematic configuration of an encoding circuit in the encoding/decoding section 111 of the facsimile apparatus of this embodiment.

In the figure, a line length counter 11 counts the number of image data for one line of encoded line data 23 and detects the end of one line. Reference numeral 12 denotes an encoding unit which inputs serial image data of encoded line data, performs MH or MR encoding processing, and outputs an encoded code 16 and its code length 17 as the encoding result. Furthermore, when the code length counter 13 notifies that the sum of the encoded codes for one line exceeds a predetermined amount, the code length counter 13 finishes one encoding currently being processed, and then outputs a unique mode start code (STI or 5T2). ), the encoding process is suspended until the end of the line.

A code length counter 13 counts the encoded code length output from the encoder 12 for each line. 14 is a serial/parallel conversion unit which converts the encoded line data 23 to be encoded into a 7-bit parallel signal, and outputs 8-bit data (unique encoded code) with the 8th bit set to "1".

Reference numeral 15 denotes a byte pack section, which inputs each of the encoded code pattern 16.20 and code length 17.21 output from the encoder 12 or the serial/parallel converter 14;
It is converted into continuous 1-byte data and output as code data. 18 is a strobe signal indicating that the encoded code pattern 16 and code length 17 are valid, and 19 is a strobe signal indicating that the unique code code pattern 20 and code length 21 are valid.

22 is reference line data (β
. ), 23 is the encoded line data (βl) to be encoded, and CK is the reference encoded line data 23
data clock. Reference numeral 24 is an excess signal indicating that one line of encoded code has exceeded a predetermined length, and is a signal that becomes "1" when the encoded data amount of one line exceeds a predetermined value. Reference numeral 25 denotes an encoding stop signal, which is a signal for suspending MH and MR encoding and validating uniquely encoded data output from the serial/parallel converter 14.

26 is the termination signal of one line, and the one line length counter 11
This is a signal indicating the end of one line of encoded line data output from and encoded. Further, 28 is encoded data that is backed up and output in byte units.

Hereinafter, the encoding operation in the encoding circuit of this embodiment will be explained in order, taking MR two-dimensional encoding as an example.

At the start of one line, the encoding unit 12 executes MR two-dimensional encoding, and for each encoding, the encoded code 16 and its code length 17 are outputted and sent to the byteback unit 1.
5 is input. At this time, the code length data 17 is accumulated by the code length counter 13.

When the value of the code length counter 13 exceeds a predetermined value while repeatedly performing the above operations, this is communicated to the encoding section 12 by the excess signal 24. The encoding unit 12 is in vertical mode,
Excess signal 24
senses the state of When it is recognized that the code length of one encoded line exceeds a predetermined value, from then on, the unique mode start code (STI, 5T2 in Figure 3) indicating that it is not an MR code is transmitted to the encoded code 16. is output to code length 17.

Thereafter, the serial/parallel converter 14 is instructed to perform subsequent encoding using an encoding stop signal 25. At the same time, the byte-back section 15 switches the input of subsequent encoded data from the encoded code 16 and code length 17 to the original encoded code (RM) 20 and its code length 21.

The serial/parallel converter 1 is activated by the encoding stop signal 25.
4, the serial/parallel conversion unit 14 converts the image data (β1) 23 of the encoded line into a parallel signal for 7 bits, and converts this into a parallel signal from the Oth bit to the 6th bit. do. Then, the 7th bit is “1”
” is outputted to the 8-bit unique code data (RM) 20 and outputted to the byte-back unit 15. Thereafter, the same operation is repeated until the 1-line length counter 11 outputs the 1-line end signal 26. .

In this way, when the end of one line is notified by the termination signal 26 from the one line length counter 11, the serial/parallel converter 14 finishes inputting 7 bits of data.
After outputting the code including the final pixel, a signal 27 notifies the encoding unit 12 that one line has ended.

As a result, the encoding unit 12 invalidates the encoding stop signal 25 and outputs the line end signal EOL code to the encoded code 16 and its code length 17. And again 1
The line length counter 11 and code length counter 13 are reset, and encoding of the next line is started.

[Explanation of encoding codes (Figures 2 and 3)] Figure 3 shows a unique mode start code (STI, 5
An example of the format of each code of T2) and a unique encoding code (RM) is shown below.

Sr1 is a unique mode start code used when the coding line is in the two-dimensional coding mode of the MR code. STI
is a unique mode start code used when the encoding line is in one-dimensional encoding mode of MR code or MH encoding. In addition, RM is the unique mode start code (STI) mentioned above.
, 5T2), followed by the format of the code encoded by the serial-parallel converter 14 described above, and FIG. 3 shows the code according to this embodiment, in which "1" is inserted every 7 bits of the image data. FIG. 3 is a diagram showing an example of converted data.

The Nth line is encoded using the MHI-dimensional code, and after the amount of these codes exceeds a predetermined amount, a unique mode start code (S
TI) is inserted. After this, a unique mode code (RM) continues.

Since one line of the (N+1)th line is completed before the amount of data based on the MR code reaches a predetermined amount, this line is made up of only the MR code.

Since the (N+2)th line is an MR two-dimensional code, when the length of the encoded data exceeds the predetermined length, (Sr1)
Similar to the Nth line, the following lines are encoded using a unique mode code (RM).

[Operation Description (FIGS. 1 to 6)] FIG. 5 is a flowchart showing one line encoding processing in the encoding section 12 of the embodiment.

First, in step S1, it is determined whether encoding is to be performed by one-dimensional encoding or two-dimensional encoding, and in the case of one-dimensional encoding, the process proceeds to step S2, where the encoded line data 23 is
The data is dimensionally encoded and output to the byteback unit 15. on the other hand,
In the case of two-dimensional encoding, the process advances to step S3, where the encoded line data 23 is two-dimensionally encoded and output to the byte pack section 15.

Next, in step S4 or step S7, it is checked whether the excess signal 24 from the code length counter 13 is input. If the excess signal 24 is not input, the process advances to step S5 or step S9, and the line end signal is input from the line length counter 11. Check whether number 26 has been input. When the end signal 26 of one line is not input, the process returns to step S2 or step S3 and the aforementioned encoding process is continued.

On the other hand, if the termination signal 26 is input before the excess signal 24 from the code length counter 13 is input, step S13
Proceed to 1, output the EOL code indicating the end of the line, and
End the line encoding process.

Also, in step S4 or step S7, the excess signal 2
4 is input, the unique code mode start code STI or Sr1 is input in step S6 and step S8.
is output and the process proceeds to step SIO. Next step S10
Then, the encoding stop signal 25 is output to the serial/parallel converter 14. Thereafter, in step Sll, the signal 27 is input from the serial/parallel converter 14, and it is checked whether encoding of one line has been completed. When the signal 27 is input and the encoding of one line is completed, the process advances to step S12 and the encoding stop signal 25 is turned off. Then, in step S13, a line end signal EOL code is output, and the process ends.

FIG. 6 is a flowchart showing the encoding process in the serial/parallel converter 14.

This process is first started by inputting the encoding stop signal 25 from the encoding section 12 in step S21. As a result, the process advances to step S22, where the encoded line data 2
3 is encoded using a unique encoding mode (RM) and output to the byte pack unit 15. Next, the process advances to step S23, where the 1-line end signal 26 is counted from the 1-line length counter 11.
If the termination signal 26 is not input, the process returns to step S22 and the encoding process continues.

When the termination signal 26 is inputted in step S23, the process proceeds to step S24, where the code including the final pixel is output to the byte-back unit 15, and in step S25, the encoding unit indicates that the encoding of one line has been completed using the signal 27. Notify 12. As a result, steps S12 to S1 in FIG.
3 is executed.

In addition, in the above-mentioned embodiment, in order to distinguish between MH and MR codes and unique code modes (RM), STI and S72 codes are used.
However, the present invention is not limited thereto. That is, when receiving and decoding an encoded code as in this embodiment, the value of the code length counter 13, which is the condition for transitioning to the unique code mode used at the time of encoding, is set on the decoding processing side. However, this can be achieved by setting them to the same value. As a result, the start position of the unique code code can be recognized by counting the encoded data length of one line during decoding processing, so there is no need to deliberately insert the unique code mode start code (ST1.5T2) as in this embodiment. Good too.

Although the configuration of the decoding circuit is not particularly shown in this embodiment, it includes a known decoding circuit that decodes code encoded by one-dimensional encoding or two-dimensional M encoding,
It is equipped with a counter having the same configuration as the code length counter 13, and a conversion circuit that performs inverse conversion of the serial/parallel conversion section 14. Until the counter counts a predetermined number, image data is decoded by a known decoding circuit, and the counter After counting a predetermined number, this can be realized by converting the image data using a conversion circuit.

In addition, in this embodiment, the unique encoding code is used for converting data from serial to parallel; however, the present invention is not limited to this; one-dimensional encoding or two-dimensional encoding can improve compression efficiency. If not, of course, any encoding method may be used as long as it can achieve higher compression efficiency.

In addition, in the unique mode encoding method of the embodiment described above, 1
At the end of a line, it is encoded using 7-bit image data including the end pixel, so it contains a maximum of 6 bits of invalid image data. Therefore, during decoding processing, normal Ml(
Or for lines encoded only with MR codes,
If the original image data length of the decoding result is not equal to a predetermined length, it is determined to be an error image, but for lines in which the unique code mode is used, this error determination condition is increased from the predetermined value by +6. - It is necessary to allow up to the range of 〇.

As explained above, according to this embodiment, MH or MR
In encoding the image line, the compression ratio becomes very poor (
By encoding using other encoding modes,
The compression rate of image data can be further increased. As a result, for example, when the value of the code length counter 13 reaches one line of original image data, the mode is switched to the original encoding mode, and the code length currently encoded by MR encoding is six times that of the original image data. If the number increases, up to 1/6 from the beginning of one line will be MR encoded, and the remaining 5/6 will be encoded using the unique encoding mode.

In the case of this embodiment, since seven pixels are represented by 8-bit codes, the following equation can be obtained, and at worst the increase can be suppressed to about twice as much.

[Effects of the Invention] As explained above, according to the present invention, when the number of encoded bits for one line becomes large, encoding according to the one-dimensional or two-dimensional encoding method is interrupted, and thereafter This method has the effect of reducing the amount of encoded data for image data with many changing points by using an encoding method that does not depend on the amount of changing points in the image.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the encoding/decoding section of the facsimile machine of this embodiment. Fig. 2 is a block diagram showing the schematic structure of the facsimile machine of this embodiment. Fig. 3 is the start of the unique code mode. A diagram showing an example of a code and a unique code. FIG. 4 is a diagram showing an example of a data string obtained by encoding image data in this embodiment. FIG. The flowchart shown in Figure 6 shows the serial
It is a flowchart which shows the encoding process in a parallel conversion part. In the figure, 11... 1 line length counter, 12... Encoding section, 13... Code length counter, 14... Serial parallel conversion section, 15... Byte pack section, 16...
... Encoding code, 17... Encoding code length, 18,
19...Strobe signal, 20...Unique encoded code, 21...Unique encoded code length, 24...Excess signal, 25...Encoding stop signal, 26...L line termination signal , lOO...Reading unit, 101...Control unit, 1
02...Recording section, 103...Operation section, 104...
Display section, 111... Encoding/decoding section. Figure 6

Claims (2)

[Claims] (1) A facsimile device that compresses and transmits/receives image data, comprising an encoding means for encoding the image data by one-dimensional encoding or two-dimensional encoding, and one line encoded by the encoding means. determining means for determining whether the amount of code has exceeded a predetermined amount; and when the determining means determines that the amount of encoded code has exceeded the predetermined amount, the encoding by the encoding means is interrupted. , a control means for controlling the image data to be encoded using an encoding method different from that of the encoding means, and a facsimile apparatus according to claim 1. (2) A claim characterized in that the control means encodes from the time when the code amount exceeds the predetermined amount until the end of the line using an encoding method different from that of the encoding means. The facsimile machine according to item 1.