JPS5843943B2 - how to move - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document and image information compression method aimed at more effectively shortening facsimile transmission time.

In facsimile, if the calligraphic information obtained by scanning the transmitted document was sent raw to the receiving end, the transmission time would be too long, and in fact, such calligraphy information would be transferred to low-speed commercial It is impossible to transmit using lines.

Conventionally, as one solution to this problem, a method has been known in which blank areas between printed lines in a transmitted document are skipped and only lines where characters are scanned are scanned to obtain transmitted calligraphy information.

However, in this conventional method, if even one character exists on a scanning line, other redundant blank information for that scanning line will also be given as transmission document image information, so compression performance cannot be expected to be very high, and the image This method has the disadvantage that it cannot be applied to transmission originals such as the following.

SUMMARY OF THE INVENTION In view of the drawbacks of the conventional methods, it is an object of the present invention to provide a more effective and high-performance information compression method that removes printed line spacing, character spacing, and other blank information in a transmission document as much as possible.

Next, the principle of the method of the present invention will be explained.

Figure 1 shows an example of a transmitted document.For convenience, this is 100 bits in the main scanning direction and 20 lines in the sub-scanning direction, for a total of 2.0 bits.
It is assumed that the image is divided into 00 pixels.

When this transmission document is scanned and the results are quantized, calligraphy information as shown in FIG. 2 is obtained.

Now, this calligraphy information is stored in each block 1 in the scanning line direction.
Let's try dividing it into 10 blocks of 0 to 9 with a 0 bit configuration.

In this case, for example, in the second scanning line, necessary black area information is included only in blocks 5 and 6, and only redundant white area information exists in the other blocks.

The same thing applies to other scanning lines.

The present invention focuses on this point, and instead of finally transmitting the writing and painting information of each scanning line, only the writing and painting information of the block containing the black area information is transmitted.

As is well known, the writing information of adjacent scanning lines is compared bit by bit, and the area where the two match is determined by "
0'' (for convenience, referred to as delta white information) and the area of mismatch is set to ``1'' (for convenience, referred to as delta black information), the obtained delta document information has a shortened run length for the delta black information, and the delta white information is The run length of information tends to increase.

Therefore, if the above-described compression method is applied to such delta drawing information, the information compression performance will be further improved.

Therefore, the details of the method of the present invention will be explained below using the case of this delta calligraphic information as an example.

FIG. 3 shows the delta calligraphic information of FIG. 2.

This delta drawing information is divided into 10 blocks in the scanning line direction as in the case of FIG.

It will be easily understood that in this case, the number of blocks to be transmitted is further reduced compared to the case of FIG.

By the way, if we examine the delta drawing information in Figure 3 in detail, we will find that because there is a strong correlation between adjacent scanning lines, the delta black information for each scanning line often has a run length of about 1 bit at most. .

Therefore, if blocks in which about 1 bit of delta black information exists are ignored, the number of blocks to be transmitted will be drastically reduced.

If we develop this idea further and ignore the leading and trailing edges of the delta black information of a block that spans adjacent blocks, the compression efficiency can be further improved. It will improve.

Even if such operations are performed, the reproduced calligraphy and pictures are generally not severely damaged.

Here, this operation will be defined as a logical correction operation.

When the above-described logical correction operation is applied to the delta calligraphy information shown in FIG. 3, the calligraphy information shown in FIG. 4 is obtained.

Here again, the delta image information of each scanning line 0 to 19 is divided into 10 blocks.

FIG. 5 is an example of compressed transmission information when the present invention is applied to the delta drawing information after the logical correction operation.

This transmission information is basically configured for each scanning line in the following format.

Transmission information: Mode signal Child block signal + data The mode signal consists of 1 bit, and displays "1" when there is a black area on the scanning line, and "1" when the scanning line is all white.
0"' is displayed.

And when the mode signal displays tl Otl,
No flock signal or data is added to the transmission information of that scanning line.

The block signal has the number of bits equal to the number of blocks into which the calligraphic information is divided, and each bit position is associated with a block number, and "1" indicates that there is transmission data of the corresponding block. + means that there is no transmission data for the corresponding flock.

This block signal is followed by transmission data (calligraphy information) for each block.

In FIG. 4, for example, the 0th scan line is all white, and the 5th and 6th blocks of the second scan line have delta black information to be transmitted.

Therefore, as shown in FIG. 5, the transmission information for the 0th scanning line only needs to be the mode signal 0'', and the transmission information for the 2nd scanning line is the mode signal ``O'' after the mode signal n 1 n.
A block signal of ``OOO011000'' and 10-bit delta information of blocks 5 and 6 are added.

The same applies to other scanning lines.

FIG. 6 is a schematic diagram of an embodiment of the compression method according to the present invention.

Here again, the description will be made on the assumption that the writing and drawing information of the -scanning line is composed of 100 bits, and this is divided into 10 blocks.

A transmission document is scanned, and the quantized calligraphic information is sequentially taken into a shift register 1 and simultaneously applied to a comparison circuit 2.

The shift register 1 has a storage capacity sufficient to store one scanning line's worth of stroke information, and is constructed of 100 bits here.

At the same time that the writing information for a new scanning line is stored in the register 1, the writing information for the immediately previous scanning line is sent out from the register 1, and is supplied to the comparison circuit 2.

Comparison circuit 2 compares the new scan line information from line a with the new scan line information directly given from line a, and outputs an "O" signal if they match, and outputs a "1" signal if they do not match. '' signal on line C.

Reference numeral 3 denotes a buffer register having the same 100-bit configuration as the shift register 1, in which delta drawing information for one scanning line outputted from the comparator circuit 2 is stored.

The delta drawing information from the comparison circuit 2 is sent to the logic operation unit 4.
Here, the presence or absence of delta black information is determined for each block, and if it exists, a “1” signal is sent, and if it does not exist, a “0” signal is sent through the line f.
It is supplied in series or in parallel to the block status display register 5 having a bit configuration.

That is, each bit position of the register 5 corresponds to a block number, and an On or ``1'' signal is displayed at the corresponding bit position of the block number.

6 is a gate circuit, 7 is a mode display flip-flop, and 8 is a transmission control section.

Assume now that the contents of buffer register 3 are all delta white information.

At this time, the flip-flop 7 assumes the "O" state in response to an instruction from the logic operation unit 4, and a "0" mode signal is sent to the FIFO (not shown) of the transmission control unit 8 via the line i.
In Fi-rst 0ut) stored in the buffer register.

Further, in this case, the 0 to 9 bit positions of the block status display register 5 are ffO91.

The gate circuit 6 has a plurality of gates corresponding to each block, and is controlled by the bit in the corresponding block position of the block status display register 5, but as mentioned above, the contents of the block status display register are all "On". , therefore, the gate circuit 6 is in a closed state and nothing is output to the line g.

Now, it is assumed that delta black information exists in, for example, blocks 5 and 6 in the -scanning line of delta drawing information stored in the buffer register 3.

At this time, under the control of the logic operation unit 4, the 5th and 6th bit positions of the block status display register 5 are set to N1t.
+, the other bit positions become 0'', and at the same time the flip-flop 7 is set to the ``1'' state.

First, the contents of the flip-flop 7 are stored as an n 1 n mode signal in a FIFO buffer register (not shown) of the transmission control unit 8 via the line i, and then the register 5
The content of is transmitted as a block signal to the transmission control unit 8 via line g.
is stored in a FIFO buffer register (not shown).

Thereafter, the contents of buffer register 3 are sequentially transferred block by block to line d.

~d9 to the gate circuit 6, which is the line e.

-e, gated with the contents of the block status display register 5 given as a gate signal to the gate circuit 6,
Only the delta drawing information of the matched block is stored in a FIFO buffer register (not shown) of the transmission control unit 8 via a line.

That is, the gate circuit 6 has a plurality of gates corresponding to each block, and is controlled by the bit at the corresponding block position of the block status display register 5.

For example, in the case of the second scanning line in FIG. 4, the 5th and 6th bit positions of the block display register 5 are 1, and the other bit positions are 0, so the gate corresponding to the block in the gate circuit 6 is Only blocks 5 and 6 will be opened, and of the contents of buffer register 3, only the contents of blocks 5 and 6 will pass through the gate and be sent to the FIFO buffer register in transmission control circuit 8 and stored therein. Other blocks are blocked by gates and do not reach the transmission control circuit 8.

Therefore, the delta image information stored in the FIFO buffer register of the transmission control circuit 8 is only that of blocks 5 and 6 in this example, and the other 0, 1, 2, 3,
Blocks 4, 7, and 8.9 are not stored.

Then, it is compressed in this way and sent to the FIF of the transmission control unit 8.
The information for one scanning line stored in the O-buffer register is sequentially modulated via MODEN or the like (not shown) in the transmission control section 8 and sent to the line.

Thereafter, the above-described operation is repeated for each scanning line, and the compressed information of the bit pattern as explained in FIG. 5 is transmitted over the line.

The information compressed and transmitted in this manner is decompressed on the receiving side by an operation opposite to the compression described above, and the original calligraphy information is restored.

In the decompression operation, for example, when the received mode signal is 0'', only O?+ bits for one scanning line are generated, and when the mode signal is 1'', the block signal is referred to, and the block signal is For "0" blocks, 00 for one block
For blocks whose block signal is 1, the delta calligraphy information is obtained by reproducing the received delta calligraphy information of the corresponding block, and based on the delta calligraphy information, the calligraphy drawings shown in Figure 2 are generated. All you have to do is play back the information.

FIG. 7 is a block diagram schematically showing an example of an information decompression device for the information compression device of FIG. 6.

Of the compressed information in units of one scanning line that arrives from the line,
The mode signal is sent to the mode status display flip-flop 9.
The block signal is stored in a block status display register 10 with a 10-bit configuration, and the delta print information of a desired block is stored in a buffer register 11 with a maximum of 100 bits with a 10-bit l block configuration.

12 is a gate circuit having the same configuration as circuit 6 in FIG. 6;
13 is 10 in which the reproduced drawing information of the previous scanning line is stored.
Shift register with 0 bit configuration, 14 is an inversion circuit, 15
is a selection circuit.

When the flip-flop 9 is in the “O?!” state, the selection circuit 1
5, the contents of the shift register 13 are directly sent from the line p through the selection circuit 15 to the output line r, and are stored in the shift register 13 again.

On the other hand, when the flip-flop 9 is in the "1" state i, the following processing is performed.

That is, for a block whose block state display register 10 indicates the "09! state", the gate circuit 12 does not output a signal to the line n, and in that case, the selection circuit 15 selects the line p, and the contents of the shift register 13 change to the corresponding 1. block, line r
will be sent to.

Further, for a block in which the register 10 indicates the "1" state, the gate circuit 12 sends the delta drawing information of the corresponding block received in the buffer register 11 to the selection circuit 12 via line n.

Then, the line p becomes valid for the bit whose delta drawing information is in the 0'' state, and the line q becomes valid for the bit whose delta drawing information is in the "1" state, and is sent from the selection circuit 15 to the line r. At the same time, the bit is sent to the shift register 13. Stored.

Up to now, we have explained the case where the document information of 100 bits of -scanning line is divided into 10 blocks of 10 bits per block.Of course, this is just an example, and in general, the bit structure of one scanning line is divided into 10 blocks. , the number of blocks is arbitrary.

For example, it is effective to pay attention to the redundancy of the blank space between characters in the transmission document and decide the division unit so that the blank space between characters spans at least several blocks and becomes "Ou."

Furthermore, it is also possible to use, as the transmission data, information obtained by encoding the calligraphy and drawing information in units of blocks.

As described above, according to the drawing information compression method according to the present invention,
High-performance compression of calligraphic information is possible with a relatively simple system configuration.

[Brief explanation of drawings]

Fig. 1 is an example of a transmitted manuscript, Fig. 2 is calligraphy information obtained by scanning the original shown in Fig. 1, Fig. 3 is delta calligraphy information thereof, and Fig. 4 is delta calligraphy information after logical correction operation. Fifth
The figure shows an example of the transmission information format applied to the method of the present invention, FIG. 6 is a block diagram of an embodiment of the information compression method according to the present invention, and FIG. 7 is a block diagram of an embodiment of the information decompression method. be. 1...Shift register, 2...Comparison circuit, 3...Buffer register, 4...
・Logic operation unit, 5...Block status display register, 6...Gate circuit, 7...
Flip-flop for mode display, 8...Transmission control unit.

Claims (1)

[Claims] 1 Divide the calligraphy information into a plurality of blocks in the main scanning direction, detect the presence or absence of information for each block, and if the information does not exist in the scanning line, send a mode signal indicating that the information does not exist. If information exists in the scanning line, a mode signal indicating the presence of the information, a signal indicating the position of the block where the information exists, and calligraphy information only for the block where the information exists, A method for compressing document and image information that is characterized by sequential transmission in a temporally continuous manner.