JPS5937911B2 - Skip method facsimile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a skip type facsimile, and more particularly to a skip type facsimile having a simple redundancy reduction function.

It is known that image information obtained by decomposing an image into scanning lines, such as a facsimile signal, has a strong correlation between the focused information and surrounding information, and is highly redundant.

Therefore, it is possible to implement high-speed transmission by suppressing or removing the redundancy of information, and in particular, by encoding information using methods such as R-L (run length), mode, correlation, and prediction, data modem High-speed facsimile sending and receiving is carried out by. However, these methods can only be realized by employing a data modem with a low error rate and a complex error control scheme, since the information is significantly degraded when noise enters the transmitted data, and is therefore very expensive. It had some drawbacks. On the other hand, in order to take advantage of redundancy and simply obtain high speed, it is possible to use the transmission section of a normal analog transmission facsimile and omit the recording of the scanned portion where there is no information determined by the transmitter. A skip method facsimile has been proposed that transmits information instructing the receiver to skip recording scanning. Various proposals have been made regarding the transmission and skipping method of O-skip control information, but in any case, The O-line skip method, which can be divided into line skip or block skip, is used when the information of one scanning line is completely white and does not need to be recorded, and skip control information (in the case of multiple lines, information on the number of skip lines) is placed in the phase interval or near the phase interval. ) is inserted and transmitted, and on the receiving side, sub-scanning is skipped using skip control information. Also, in the program skip method,
One scanning line is divided into a plurality of blocks, and information for skipping all-white blocks in which there is no information to be recorded is inserted and transmitted near the phase interval, similar to line skipping.
The former controls the receiver, but it is easy to maintain the phase synchronization relationship between the transmitter and the receiver, but it can be skipped only when the photoelectric conversion information is completely white for one scanning line, and it cannot be skipped depending on the transmitted original. For example, if there is a vertical line in the sub-scanning direction, high speed cannot be expected.Also, the latter can be said to be a skipping method that adapts to the information content because it skips within one scanning line, but When information is distributed over multiple blocks, a simple transmission method is used to omit the information in the skip part during transmission even though the recording blocks are far apart, so adjacent information due to transmission characteristics is used. In addition, in order to transmit program skip control information efficiently and accurately, a transmission means similar to a data modem is required. The purpose of the present invention is to propose a skip type facsimile capable of shortening the transmission time by reskipping as much as possible even when there are relatively many lines (for example, up to about 50% of one scanning line). It determines whether the information on multiple scanning lines matches and whether it is possible to finish recording that information before the skip operation, and creates skip control information based on the results of this determination to control the operation of the transmitter and receiver. A preferred embodiment of the present invention is characterized in that both the transmitter side and the receiver side use buffer memories with an amount of information greater than one scanning line, and as a skip condition, on the transmitter side, The information sent in the previous line and the information in this line match, and the predetermined skip point (a point every 1/n scanning line, including the synchronization interval)
It is determined whether or not recording is completed by then, and if the conditions are met, the recorded information is not transmitted and skipped to a certain position near the phase interval of the facsimile signal consisting of the phase interval and the image information interval. A control signal instructing the skip point is inserted, one scanning line is shortened to the skip point, and transmitted. On the receiving side, according to the control signal, the received information of the previous line is used again to skip the white line. The purpose is achieved by recording.

Note that if skipping is possible and the information for one scan is all white, a specific control signal is assigned to indicate the shortest skip point and all white.

Of course, if the condition is not satisfied, the normal facsimile signal is transmitted as is. Hereinafter, an explanation will be given according to an embodiment.

Figures 1A and 1B show modeled facsimile signal waveforms, where a is the conventional facsimile signal waveform without a skip, and b is the waveform with a skip.0Table 1 below is a control signal allocation table. In this example, the number of skip points for one scanning line is only 1/3. If there is a skip for a normal transmission waveform, the phase In normal facsimile standards (CCIT Tl Electronics Industry Association, etc.), sections CNl and CN2 are assigned as skip control signals within section Tp.
The phase interval Tp is defined as 4 to 601) for one scanning line interval T, and the image interval T is defined as the remaining 94 to 96%.
However, this skip control signal section is CNl,
Even if both CN2 are combined, it is considered to be well within the variation of 1 to 2%, and the normal recording density of facsimile is 4d0.
When converted to t/d0t, it corresponds to 10 to 20d0t, and the information can be sufficiently identified even by using simple transmission means. In Fig. 1, PL indicates a fixed position within the phase interval TP. Hereinafter referred to as the pilot signal 〇WH is the section (corresponding to the white signal) in which the receiver transmits the carrier for operating the automatic gain control circuit and for carrier regeneration synchronization used for synchronous detection 〇Skip control signal C
Control information is assigned to Nl and CN2 as shown in Table 1. When 0, that is, no skip, both are completely white and the same as the conventional signal waveform, and when a skip is present, CNl is black, and even with a skip. If there is a record, CN2 is white,
If there is no color (all white continues), black is assigned.

FIG. 2 is a block diagram of the transmitter side. 1 is a phase signal generation circuit, 2 is a photoelectric conversion circuit, 3 is an image signal memory, 4 is an information amount determination circuit, 5 is a signal synthesis circuit, 6 is a modulation circuit, 7 is a pulse motor, and 8 is a clock generation circuit.

The phase signal generation circuit 1 generates timing signals DST and VDW used in each element based on the signals CLKl and NOVD.
T, QVD, CINPl, CINP2, VDRD, PS
Create IG and MSTEP.

The signal DST is a conversion readout command signal that instructs the photoelectric conversion circuit 2 to read out image information for one line (scanning line), and the signal VDWT is a readout period signal that indicates a period during which image information is read out from the photoelectric conversion circuit 2. Signal QVD is a skip inquiry signal indicating whether or not skipping is possible, signal CINP1 is a skip enable output command signal to output a skip enabled signal CSIG1 indicating if skipping is possible, and CINP2 is a skip enable output command signal indicating whether skipping is possible. This is a command to output the recording presence/absence signal CSIG2, which indicates whether or not the VD
RD is a command to read the image information written in the image signal memory 3, and MSTEP is a step pulse that commands the pulse motor 7 to transport the document. The detailed configuration of the phase signal generation circuit 1 is shown in FIG.

The counter 1A and the encoder 1B determine the main scanning period, and if the skip is possible as a result of outputting the 0 skip inquiry signal QVD determined by the skip enable signal NOVD from the information amount determination circuit 4, the skip enable signal NOVD is output. It will come back as a response, but if it is not possible, it will not come. If the skip enable signal NOVD is returned, the next main scanning period is set to T/3 (Sec), and if it does not come, the next main scanning period is set to T/3 (Sec).
) The counter 1A is loaded with a value such that and T/3, where the image information of this line is equal and the recording operation on the receiving side is the skip point.
This is a case where the process is completed within (Sec), and of course includes the case where two lines are completely white.

Manuscripts for submission often include squares to make it easier for the writer to write, but even with these squares,
In fine scanning line decomposition, the information often matches the previous line.Of course, this also includes cases where all-white lines continue,
If the photoelectric conversion circuit is equipped with a circuit that ignores thin vertical lines such as continuous lines in the sub-scanning direction, it is possible to force the photoelectric conversion information to be an all-white line when there is no text information. Possible〇In the photoelectric conversion circuit 2, the photodiode
- High speed reading elements such as door arrays are used.

Conversion read command signal DST from phase signal generation circuit 1
When 0 comes, one line of image information is read out. This image information signal ID goes to the image signal memory 3, where it is stored. At the same time, it goes to the information amount determination circuit 4, and it is determined that this read line can be skipped. The 0-picture signal memory 3 in which it is determined whether the 0-picture signal is
The detailed configuration of the o-information determining circuit 4 is as shown in FIG. 7. Reading is performed using a high-speed clock pulse CLK2 synchronized with the signal transmission speed, and reading is performed using a low-speed clock pulse CLK1 corresponding to the signal transmission speed.

4A to 41 are AND circuits, 4K is an exclusive OR, 4L and 4M are S/R flip-flops, and 4N is a counter.

The flip-flop 4L is reset by the conversion read command VDST, and is not set when there is no image information. 4M is the information VSIG2 of the previous line stored in the image signal memory 3 and the information signal VI read out by the photoelectric conversion circuit 2.
This is a circuit that holds the result of the OR circuit 4K determining the match with D, and after being reset by the conversion read command VDST, a 0 counter that is not set unless there is a mismatch between the read period signals and the output signal. 4N is a counter that counts the amount of information in one line, and if the number of pixels to be recorded is less than a certain value by counting the high-speed clock signal CLK2 corresponding to the recording information, the counter 4N counts the amount of information in one line. The level is not inverted. The AND circuit 4E outputs when the results of the flip-flop 4M and counter 4N both hold true (that is, when the information on this line matches the information on the previous line and the amount of information to be recorded is small). is "1", and in response to the skip inquiry signal NOVD, a skip enable signal NOVD is returned. Further, when the skip enable signal NOVD to the flip-flop 4E is returned, the skip command signal CSIGl is returned in response to the skip enable output command CINPl, and a control signal is inserted into the transmission signal.0Also, if the output of 4L appears at the same time as the AND circuit 4E In response to the recording presence/absence output command CINP2, a recording presence/absence signal CSIG2 is returned, and 2 is sent as a control signal.
If the above conditions are satisfied, the output of this circuit is the pilot signal PL of the phase interval TP.
The main scanning period inserted subsequent to PL is shortened to T/3 (Sec), and if the transmitted 0 or the condition is not satisfied, the skip enable signal NOVD is not returned, and the skip information after the pilot signal PL is set to white level. Thus, the image signal is transmitted in the image information section T. The signal synthesis circuit 5 receives the information signal VSIGI read from the image signal memory 3, the skip command signal CSIGI1 from the information amount determination circuit 4, and the recording presence/absence signal CSIG2. , is a circuit for ORing the pilot signals PSIG from the phase generation circuit 1 and synthesizing them.The synthesized composite signal MXDT enters the modulation circuit 6.
In this case, the o-pulse motor 7, which performs AM-PM modulation, receives the power supply pulse MSTEP from the phase signal generation circuit 1 every time it enters the phase interval and conveys the document.The o-clock generation circuit 8 sends clock signals CLKl, CLKl, It is for supplying CLK2, and is generally composed of a crystal oscillator and a frequency dividing circuit.

This output CLKl is a low-speed clock according to the transmission speed, and CLK2 is a high-speed clock for reading image information from the photoelectric conversion unit 2 to the image signal memory 3. Figure 3 shows the waveforms showing the operation on the transmitting side. It is a diagram.

TP/TV is only generated inside the phase signal generation circuit, but since it is a signal representing a phase interval, conversion readout is performed at the beginning of the phase interval TPl, TP2, TP3, etc. shown for reference. The command DST is issued and one line of image information is read out from the photoelectric conversion section.At the same time, the readout period signal VDWT is generated to inform the image signal memory 3 and the information amount determination circuit 4 that image information is being read out. A skip inquiry signal QVD is generated from the phase signal generation circuit 1 at the end of the 0 phase interval, and the 0 phase interval T is inquired of the information amount determination circuit 4 as to whether or not skipping is possible.
In the case of Pl, since the first line is being scanned and there is image information, the skip enable signal NOVD is not returned.

Therefore, in the phase signal generation circuit 1, the next main scanning period T(S
The internal counter 1A is loaded so that ec) is obtained.
Similarly, the skip enable output command C from the phase signal generation circuit 1
INPl is output, but if the contents of the image signal memory 3 are completely white when the power is turned on, the first photoelectric conversion signal contains image information, so the image signal memory 3 corresponds to the information of the previous line. The skip command signal CSIGl is not output, and the recording/non-recording output command C
The recording presence/absence signal CSIG2 is also not output to INP2 (it is '0').

The pilot signal PSIG is a pulse indicating a certain period in the phase interval, and is output unconditionally.The signal obtained by combining these signals is the composite signal MXDT, which is modulated to become the modulated output signal MDDT. Viewed from the beginning of the phase section, the first block is the white signal WH1, the second block is the pilot signal PL1, and the third block is the skip control signal (hereinafter referred to as CN information). The pilot signal PL corresponds to a black signal with white signals at both ends, and the CN information corresponds to a black signal when there is a skip, and a white signal when there is no skip. Note that a white signal indicates that a carrier is present, and a black signal indicates that there is no carrier signal. T.P.
When the interval l ends, there is no skipping, so image information is subsequently read out from the image signal memory 3 (SIGl) and transmitted. When it ends, the phase interval TP2 begins and the conversion readout command VDSTl Readout period signal VDWT occurs, and one line of image information is read again.

In the figure, since it coincides with the previous line and the amount of information is small, when the skip inquiry signal QVD is generated in the phase signal generation circuit 1, the skip enable signal NOVD is returned as a response, and the next main scanning period is set to T/3 (Sec). Similarly, the skip enable output command C is loaded to the counter 1A.
When INPl occurs, the information amount determination circuit 2 outputs a skip command signal CSIGl, and a recording presence/absence output command C
When INP2 occurs, recording information exists, so the recording presence/absence signal CSIG2 is not returned. Pilot signal PS
Since IG is output unconditionally, a signal obtained by combining these signals is sent out as modulated output signal MDDT. When this phase interval TP2 ends, no meaningful signal is sent until the next phase interval TP3. Time elapses again, and when the phase interval TP3 is entered, a conversion read command DST is generated and the same operation follows.

(In the figure, it is exactly the same as TP2.) Furthermore, the phase interval TP
If all lines from l to TP3 are white and there is no image information, the recording presence/absence signal C is output in response to the recording presence/absence output command CINP2.
SIG2 is returned, but other than this, the operation is almost the same as above, and the phase interval TPl to TP3 is T/3 (Sec).
A composite signal MXDT with a main scanning period of
Send a scan line.

FIG. 4 is a block diagram of the receiving side. 011 is a demodulation circuit, 1
2 is a phase signal generation circuit, 13 is a pilot signal detection circuit, 14 is a CN information detection circuit, 15 is a recording control circuit for giving a signal to the recording means, 16 is a pulse motor for conveying the received recording paper, and 17 is a 0, which is a clock generation circuit that generates a clock to supply clocks to each element.
(See FIG. 5 below) The demodulation circuit 11 is for demodulating an AM-PM modulated signal input from a telephone line, and its output is a demodulated signal DMDT.

The phase signal generation circuit 12 generates timing signals TP/T, CGTl, CGT2, QPC, and MS used in each element.
This is to create a TEP.

TP/T is a signal for distinguishing between a phase interval and an image signal interval.0PGT indicates an interval where a pilot signal is input, and 0CGT1 and CGT2, which are pilot signal check commands, indicate an interval where CN information is input. 0QPC, which is a CN information check command to indicate and check, is a pilot signal detection inquiry signal that inquires whether a pilot signal has been detected.
If the pilot signal is detected in the pilot signal detection circuit 13, a pilot signal detection report signal P is output as a response to the pilot signal detection inquiry signal QPC.
The 0CN information detection circuit 14 that returns OK returns a skip presence signal CONTl (2), which means that a skip signal is present, if a skip signal is detected.The detailed configuration of the phase signal generation circuit 12 is described in the eighth section. As shown in the figure.

The counter 12A1 encoder 12B determines the main scanning period. A pilot signal detection inquiry signal QPC is input to the load terminal of the counter 12A, and when this signal QPC is output, the counter 12A is loaded. The value to be loaded is determined by the output of the encoder 12B, which changes depending on the state of the skip signal CONTl and the pilot signal detection report signal POK.
If the skip signal CONTl is obtained when the pilot signal detection inquiry signal α°C is output, the main scanning period (time until the next inquiry signal QPC is output) is T/
3 (Sec), and if the skip signal CONTl is not obtained, it becomes T (Sec). o When the pilot signal is not detected, the main scanning period becomes T/3 (Sec) regardless of the skip signal CONTl. , this process is repeated until the pilot signal detection report signal POK is detected. The next pilot signal detection report signal POK is correctly T.
Since the signal is detected at a position that is an integer multiple of /3 (Sec), even if the pilot signal is not detected by mistake, the transmission/reception phase will not remain incorrect. When the skip signal is not detected (CO
The o signals TP/TV, PGT, CGT1, CGT2, and QPC in which only NTl=0, P0K=1) becomes T (Sec) are created by decoding the output of the counter 12A by the decoder 12C.

The detailed configuration of the pilot signal detection circuit 13 is shown in FIG.

This is a circuit that stores the demodulated output DMCT when the pilot signal check command PGT is received in the shift register 13A, and checks by the comparator 13B whether both ends of this pattern are white and the center is black. If the check passes, a pilot signal detection report signal POK is output when a pilot signal detection inquiry signal QPC is received. The detailed configuration of the CN information detection circuit 14 is as shown in FIG.

CN information check command CGTl, CGT2 (hereinafter (2)
This circuit is prepared for each of the 0CN information check commands CGTl(2), so half of the circuits are omitted.
) is checked, and if there is a black signal of a certain amount or more, the counter output Qn becomes 1 and a skip signal CONTl (2) is output. The detailed configuration of the recording control circuit 15 is as shown in FIG.
The recording control circuit 15 includes note circuits 15A to 15E, AND circuits 15F to 15N, OR circuits 150 to 15P, one memo 5Q, and a counter 15R.

When demodulated signal DMDT is input, skip signal C
When both ONTl and CONT2 are not detected, TP/
During the image information section T, the demodulated signal DMDT is stored in the memory 15.
At the same time as being stored in Q, AND circuit 15L1 OR circuit 1
At this time, the scanning clock that gives the scanning speed of the recording circuit is given as a recording signal to the recording circuit as it is through the 5P1 AND circuit 15N.The scanning clock that gives the scanning speed of the recording circuit receives control information (skip information) in the 0 phase signal section where the low-speed clock CLKl corresponding to the normal transmission speed is supplied. signal) is CONTl=1, C0NT2=
If it is detected as 0, the demodulated output DMDT is not given to either the memory or the recording circuit, and the memory 15Q enters the read mode in the recirculating state, changing the state of the output DO (
The memory 15Q is read out at a low or high speed depending on whether it is "0" or "1". In other words, the skip signal CONTl puts the memory 15Q in the recirculating state, and the clock CLK indicates that the memory output DO is a white signal. When the signal is (=O), the high speed clock CLK2 is used, and when the signal is black, the low speed clock C is used.
At the same time that LKl is applied, this clock is also applied to the recording circuit, and the read signal is applied to the recording circuit through the AND circuit 15M1, the OR circuit 15P1, and the AND circuit 15N. (Sec.
) the recording operation of this signal is completed within Furthermore, when the control information CONTl=1 and CONTS221, the AND circuit 15N is forcibly closed, so no recording signal is given even in the image signal section, and no recording is performed at all. The amount of information that can be recorded in /3 (Sec) shall be set to a small value that allows recording signals due to noise in the transmission line. Figure 5 shows the operation of the receiving side in this embodiment. 0 In the normal facsimile control procedure shown in the waveform diagram, the operation up to phase matching will be explained assuming that it has already been completed. If you look at the phase section TPl, the pilot signal has come to the center of the pilot signal check command PGT. Therefore, when the normal 0 pilot signal detection inquiry signal QPC is generated, the 0CN information check command C returns the pilot signal detection report signal POK.
Since the demodulated output DMDT generated by GTl (2) is a white signal ("0"), it is determined that there is no skip, and even if the pilot signal detection inquiry signal QPC is generated, the skip signal CONTl (2) is not returned. 0, that is, in this case, the phase signal generation circuit receives the pilot signal detection report signal POK=1 and the skip signal CONTl(2)=0, and the main scanning period becomes T (Sec).

When the phase interval TPl passes, this is the interval in which image information is sent, so it is recorded and recorded in the memory at the same time.
When the image signal section ends, the phase section TP2 is entered, and check commands PGT and CGTl (2) are generated again, and the pilot signal and CN information are checked.0 Since the pilot signal is coming normally, the pilot signal detection inquiry signal is issued. , when QPC occurs, the pilot signal detection report signal PO
K appears 〇 Check command CG in this phase interval TP2
The black signal 1 is coming in the interval T. Therefore, the skip presence signal CONTl is obtained.0 Since the pilot signal detection report signal POK = 1 and the skip presence signal CONTl = 1, the next main scanning period is T/ 3 (Sec), which is 0. This means that the phase interval is not shortened, but the image information interval is shortened.

Next, when it comes to the image information section, the skip signal CONT2
is 10°, so the receiving side reads and records the information stored in the previous line, just as the transmitting side has determined that the image information is the same as the previous line. White signals that do not need to be recorded are read out at high speed, and only black signals are scanned at low speed, so even if the main scanning period is shortened, the recording operation is sufficiently completed before the next phase section TP3 arrives. After the shortened image information interval passes, the phase interval TP3 reappears, and the operation continues in the same manner.According to this embodiment, all control information is exchanged within the phase interval, so unnecessary recording is avoided. Gradient line of a document that matches the information of the previous line and finishes within T/3 (Sec) without causing image information to be recorded continuously, even if there is information to be recorded. Information such as this has the advantage of being able to be transmitted in a short time without being omitted. In addition, even if the pilot signal is lost, it is possible to restore the phase relationship between transmission and reception in a short time. As explained above, according to the present invention, the information for controlling main scanning can be stored almost within the phase interval. It is possible to send and receive data, and it is possible to transmit efficiently without damaging the received image. Also, since the control signal is expressed with or without a carrier, no special signal is used. Can be realized with almost no changes to the conventional transmission circuit 〇In addition, control signals or
Even if the pilot signal is incorrectly received, normal recovery is easily possible.The present invention can be modified without being restricted to the embodiments.In other words, the main scanning period can be shortened by T.
Any n (n=integer) such as T/2, T/4 or T/6 other than /3 (Sec) may be used. Also, depending on the control signal, the skip point where IT/N, l≦i<n instruct the
Furthermore, a plurality of controls may be implemented.

Furthermore, each piece of control information divided into a plurality of pieces may be given a specific function as shown in the embodiment, or may be made to have a meaning as a whole code.

It is also easy to understand that the signal processing described above can be performed in the same way using a microcomputer.

[Brief explanation of the drawing]

1A and 1B are modeled transmission waveforms of facsimile signals, FIG. 2 is a block diagram showing the configuration of the transmitting side of the embodiment of the present invention, and FIG. 3 is a waveform diagram showing the operation of each part in FIG. Fourth
The figure is a block diagram showing the configuration of the receiving side according to the embodiment of the present invention.
Figure 5 is a waveform diagram showing the operation of each part in Figure 4, and Figure 6 is a waveform diagram showing the operation of each part in Figure 2.
7 is a block diagram showing the configuration of the information amount determination circuit shown in FIG. 2, and FIG. 8 is a block diagram showing the configuration of the phase signal generation circuit shown in FIG. 4. , FIG. 9 is a block diagram showing the configuration of the pilot signal detection path in FIG. 4, FIG. 10 is a block diagram showing the configuration of the control information detection circuit in FIG. 4, and FIG. 11 is a block diagram showing the configuration of the control information detection circuit in FIG. 4. FIG. 3 is a block diagram showing the configuration of the circuit.

Claims (1)

[Claims] 1. A high-speed photoelectric conversion means, a memory for storing image information output from the high-speed photoelectric conversion means, a comparison means for determining whether image information of a plurality of scanning lines matches, and a single scanning line at the time of skipping. a shortened transmission cycle setting means that sets the transmission time by shortening the transmission time; an information amount determination means that determines whether recording processing of image information of one scanning line to be transmitted can be completed within the shortened transmission time; means for generating a skip information signal based on the image information matching signal obtained from the comparing means and the termination possible signal obtained from the information amount determining means; and an operation based on the shortened transmission time based on the skip information signal. a transmission system comprising phase control means for controlling the high-speed photoelectric conversion means and memory to generate a pilot signal and a skip information signal within a phase interval of a facsimile signal; a memory for storing received image information; and a pilot signal detection means. a skip information signal detecting means; a means for generating a timing signal based on a transmission time shortened based on the outputs from the pilot signal detecting means and the skip information signal detecting means; and image information stored in the memory. 1. A skip type facsimile comprising: a receiving system comprising means for selecting received image information based on a skip information signal and outputting the selected image information as a recording signal.