JPS59131267A - Encoder - Google Patents

Abstract

PURPOSE:To attain processing of MH code conversion by reading MC and TC from the MH code table based on an output of the 1st counter and outputting MC(2560) having a numeric equivalent to an output value of the 2nd counter. CONSTITUTION:While white run or black run continues, a signal S1 is at H level and it causes a counter 1a to be enabled and a pulse signal CP is counted. When this count is repeated for 2560 times, an output terminal of the 10th bit and the 12th bit of the counter 1 goes to H level and a carry output terminal CY of a counter 1b goes also to H level, then an output of an AND circuit 3 goes to H level during one clock period. Thus, a counter 2 is enabled and the counter operation is executed, and then an output of an NOR circuit 5 goes to L level, it causes the counters 1a, 1b and 1c to be reset and the count of the counter 1 starts again from ''0''. Then, the MC (makeup code) and the TC (terminating code) are read from the counter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a facsimile machine encoding system rjit//c
related.

[Prior art]

The G3 facsimile (G3 facsimile) device, whose transmission control procedures have been determined by the CCITT (International Telegraph and Telephone Consultative Committee), uses pixel signals ( In other words, the transmission information) is encoded and data compressed.

The encoding method is so-called M H (Modify
A one-dimensional encoding method called edHuffman ) encoding method has been adopted as a standard encoding method. In this encoding method, each run length from 0 to 63 (
The MH consists of a terminating code (hereinafter referred to as TC) corresponding to the white and black run lengths generated on the l scanning line, and a makeup code (hereinafter referred to as MC) corresponding to every 64 run length from 64 to 2560. A code table is predetermined. Then, the actual run length is measured by a counter (run length counter), the TC and MC based on the measured value are read out from the MH code table, and the TC and MC are combined to form a code.

Although run lengths up to 2623 can be expressed by the simple combination of TC and MC described above, run lengths exceeding this, for example, run lengths of 3007.5219, can be expressed as follows.

3007 → MC (2560), MC (384), TC (
63)5219→MC(2560)l MG(2kelo
), prec(gtF).

TO (3 pieces) However, MC (A) is used for the MC of Lambinges A, and TC (A) is used for the TC of run length A.

In this way, the run length exceeding 2623 is changed to 2560
Conventionally, the run length is expressed as 256 units.
Calculate the quotient and remainder term by actually dividing by 0, generate as many MC(2560) as the quotient, read the remainder terms MC and TC from the code table, and calculate these M
It was a combination of C and TC.

Therefore, conventionally, the encoding device has a run length of 2623
The processing to determine whether or not the run length exceeds 2
Since a process such as division by 560 is required, the encoding process becomes complicated.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages and to provide an encoding device with an encoding processing power of 4.

〔composition〕

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

The figure shows a run length counter according to an embodiment of the invention. This embodiment combines a counter that counts up to 2560 and a counter that is incremented every 2560.

In the figure, 1 is a counter formed by cascading 4-bit counters la, lb, and 1c, 2 is a 4-bit counter, 3 is an AND circuit, 4 is an inverter, and 5 is a NOR circuit. output end b
l""'b12 and output terminals b13 to bl of counter 2
11 is connected to a control section of an encoding device (not shown).

The signal S1 is a run signal output from a scanner (not shown). Pulse = -qcp is a clock cell for counting the duration of the run signal Sx, that is, the run length, and one period thereof corresponds to the length of one run of the run signal. Further, the signal S2 is a reset signal.

With the above configuration, while the white run or black run continues, the 4g issue
, is at the logic level rI (J), which enables the counter 1a to count the signal CP. When this counting operation is repeated 2+2 (2560) times, the output terminals of the 10th bit (blo) and 12th bit (bl-) of counter 1 reach the logic level r.
At the same time, the logic level of the carry output terminal CY of the counter lb becomes rHJ, so the output of the AND circuit 3 becomes 1.
It is at logic level "H" during the clock period. As a result, the counter 2 is enabled and performs a counting operation, and at the same time, the output of the NOR circuit 5 reaches the logic level rIL.
Since the counters 1m+1b and 1c are reset, the counter 1 starts counting from "0" again.

Therefore, the 12-bit output of counter 1 is O~25.
At 59t, the output of counter 2 will be a multiple of 2560. Therefore, MH code conversion can be realized by reading MC and TC from the MH code table based on the output of counter 1 and outputting the number of MCs (2560) corresponding to the output value of counter 2, and the run length becomes 2560. Complex processing such as division processing is not required for the M H code conversion processing when exceeding the M H code.

Furthermore, in this embodiment, since the outputs of 7 to 12 bits of counter 1 are used to form the MC, and the outputs of 1 to 6 bits are used to form the TC, the MH code is The conversion process can be further facilitated.

〔effect〕

As described above, according to the present invention, code conversion processing in an encoding device can be extremely simplified.

[Brief explanation of the drawing]

The figure is a glock diagram showing one embodiment of a run length counter according to an embodiment of the present invention. 1.2... Counter, 3... AND circuit, 4...
Impark, 5...Noah circuit.

Claims (1)

[Claims] In the encoding device of the facsimile machine, a run length counter that counts the length of consecutive white pixels or black pixels of a document in the main scanning direction is used as a counter of fil and a run length counter of this first one.
The second counter is incremented when the count value of the counter reaches 2560.
1. An encoding device comprising a counter, and resetting the first counter each time the second counter increments.