Image communication apparatus and method for determining image quality in accordance with received line synchronization signals

An image communication apparatus for receiving image data includes a first detector for detecting a first line synchronizing signal for one-dimensional codes in the received image data and a second detector for detecting a second line synchronizing signal for two-dimensional codes in the received image data. The apparatus counts the number of detected second line synchronizing signals in accordance with a detection by said first detector, and determines a quality of the received image data in accordance with that number of the second line synchronizing signals. In particular, the apparatus counts the number of the second line synchronizing signals detected between one first line synchronizing signal and a next first line synchronizing signal.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an image communication apparatus having 
the function of checking a communication error. 
2. Related Background Art 
One type of conventional facsimile apparatus determines the quality of 
received image data on the basis of the number of bits between one line 
synchronizing signal and a next line synchronizing signal when the 
conventional facsimile apparatus effects G3 image reception according to 
the T4 recommendation of the CCITT (International Telephone & Telegraph 
Consultative Committee). The conventional facsimile apparatus then decodes 
the received image data, discriminates whether the number of bits 
corresponding to one line of image data is a predetermined number or not 
(i.e. whether the received line is correct or not), and then determines 
the quality of the received image data in accordance with a ratio of the 
number of correct lines to the number of incorrect lines. The conventional 
facsimile apparatus informs a destination of the quality of the received 
image data each time one page has been received. 
However, the conventional facsimile apparatus has some problems, as 
follows. 
In the case where the conventional facsimile apparatus has a laser beam 
printer (LPB) or the like and where the conventional facsimile apparatus 
records one page of the received image data at a fixed high speed, the 
conventional facsimile apparatus records a previous page while the 
apparatus is simultaneously receiving a next page. As a result, the 
conventional facsimile apparatus has to perform in parallel one decoding 
operation for checking the quality of the page being received and another 
decoding operation for recording the previous page stored in a memory, and 
a controller of the conventional facsimile apparatus has to be complicated 
and expensive. 
Further, coding methods used in G3 facsimile apparatus are the MH (Modified 
Huffman) method and the MR (Modified READ) method. The conventional 
facsimile apparatus is easily able to decode the MH code, which is a one 
dimensional coding method. However, in the case where the conventional 
facsimile apparatus decodes the MR code, which is a two dimensional coding 
method, the process of decoding the MR code is complicated because of the 
need to process both a reference line and a current line in parallel. 
Thereby, especially, the structure for decoding the MR codes is 
complicated in the conventional facsimile apparatus. 
SUMMARY OF THE INVENTION 
In consideration of the foregoing, an object of the present invention is to 
provide an improvement in this type of image communication apparatus. 
Another object of the present invention is to provide an image 
communication apparatus capable of determining the quality of received 
image data without decoding all of the received image data. 
Another object of the present invention is to provide a method which is 
easily able to check the quality of received image data. 
These and other objects are accomplished by providing an image 
communication apparatus comprising means for counting a number of second 
line synchronizing signals for two-dimensional codes between one first 
line synchronizing signal for one-dimensional codes and a next first line 
synchronizing signal, and for determining the quality of received image 
data in accordance with a count value of the second line synchronizing 
signals. 
Still other objects of the present invention, and the advantages thereof, 
will become fully apparent from the following description of the preferred 
embodiments to be taken in conjunction with the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Now the present invention will be clarified in detail by embodiments 
thereof shown in the attached drawings. 
FIG. 1 is a block diagram of a facsimile apparatus according to the first 
embodiment. The facsimile apparatus according to the first embodiment 
detects the EOL (End Of Line signal) corresponding to the MH code (the 
EOL-MH) and the EOL corresponding to the MR code (the EOL-MR), and 
determines the quality of received image data in accordance with the 
number of the EOL-MRs. 
In FIG. 1, an NCU (Network Control Unit) 2 is provided for connecting to 
and using a telephone network for data and other communication. The NCU 2 
has a relay CML (unshown) for making connections. The NCU 2 connects a 
telephone line 2a to the facsimile terminal, controls connections between 
the telephone line 2a and a telephone 4 or a hybrid circuit 6, and 
maintains a closed loop. In particular, the NCU 2 connects the telephone 
line 2a to the telephone 4 when the signal level of a signal line 36a from 
a control circuit 36 is "0". On the other hand when the signal level of 
the signal line 36a is "1", the NCU 2 connects the telephone line 2a to 
the facsimile terminal, which is constituted by all the elements in FIG. 1 
except the NCU2 and the telephone 4. In a normal condition or initial 
condition, the telephone line 2a is connected to the telephone 4. 
The hybrid circuit 6 is provided for separating the transmitting signal and 
receiving signal. In other words, the hybrid circuit 6 sends the 
transmitting signal from an adder 16 to the telephone line 2a via the NCU 
2, and transfers the receiving signal from another station via the NCU 2 
to a demodulator 18 and a demodulator 20. 
A modulator 8 is provided for modulating protocol signals from the control 
circuit 36. The modulator 8 modulates signals based on the V21 
recommendation of CCITT. 
A reading unit 10 is provided for reading image information of the original 
document line by line of main scanning, and for outputting signals having 
two values: white and black. The reading unit 10 is structured with an 
imaging device such as a CCD (Charge Coupled Device), an optical system 
and so on. The reading unit 10 also has a sensor for detecting a next 
original sheet to be sent, and provides information whether the next 
original sheet is present or not to the control circuit 36. 
A coding circuit 12 is also provided for coding information read by the 
reading circuit 8. The MH coding method and the MR coding method are 
advantageously used by the coding circuit 12. 
A modulator 14 is provided for modulating image data based on the V27ter 
(differential phase modulation) or V29 (orthogonal modulation) 
recommendation of CCITT. 
The adder 16 is provided for adding outputs of the modulator 8 and 14. 
The demodulator 18 is provided for demodulating protocol signals based on 
the V21 recommendation of CCITT. 
The demodulator 20 is provided for demodulating a received data signal 
based on the recommendation V27ter or V29 of CCITT. 
A memory circuit 22 is provided for storing image data demodulated by the 
demodulator 20 into an applicable area. The memory circuit 22 stores the 
demodulated image data into the applicable area in accordance with a 
control signal from the control circuit 36. Further the memory circuit 22 
outputs the image data to a decoding circuit 24 in accordance with the 
control signal from the control circuit 36. 
The decoding circuit 24 is provided for decoding (MH decoding or MR 
decoding) the demodulated image data from the memory circuit 22. 
A recording unit 26 is provided for recording decoded image data from the 
decoding circuit 24 on a recording material sequentially and line by line. 
The recording unit 26 records the image data at a fixed speed, and is, for 
example, an LBP. 
A EOL-MR detecting circuit 28 is provided for detecting a line 
synchronizing signal of the MH mode (EOL-MH) out of the demodulated image 
data. When the EOL-MH detecting circuit 28 detects the EOL-MH, the EOL-MH 
detecting circuit 28 outputs a detection signal to the control circuit 36. 
The EOL-MH consists of at least eleven consecutive "0"s and two following 
"1"s. The EOL-MH detecting circuit 28 detects the above mentioned pattern 
of "0"s and "1"s. 
A EOL-MR detecting circuit 30 is provided detecting a line synchronizing 
signal of the MR mode (EOL-MR) out of the demodulated image data. When the 
EOL-MR detecting circuit 30 detects the EOL-MR, the EOL-MR detecting 
circuit 30 outputs a detection signal to the control circuit 36. The 
EOL-MR consists of at least eleven consecutive "0"s and a following "10". 
The EOL-MR detecting circuit 30 detects the above mentioned pattern of 
"0"s and "1". 
A MH decoding circuit 32 is provided for decoding the demodulated image 
data in accordance with the MH decoding method. The MH decoding circuit 32 
decodes the demodulated image data in response to a start pulse from the 
control circuit 36, and continues to decode the demodulated image data 
until the next EOL-MH is detected. 
A counter 34 is provided for counting the number of bits of the image data 
decoded by the MH decoding circuit 32 in response to the start pulse from 
the control circuit 36. The count value of the counter 34 is supplied to 
the control circuit 36. 
A RTC detecting circuit 35 is provided for detecting an RTC (Return To 
Control) out of the demodulated image data. The RTC consists of six 
consecutive EOLs (each EOL consists of at least eleven consecutive "0"s 
and a following "1"). When the RTC detecting circuit 35 detects the RTC, 
the RTC detecting circuit 35 outputs a detection signal to the control 
circuit 36. 
The control circuit 36 is provided for controlling all circuits mentioned 
above and the total system of this facsimile apparatus, and is structured 
with a CPU, memories, and other conventional elements. 
The operation of the control circuit 36 is as follows. 
In the case where the facsimile apparatus receives image data in a MR mode 
at the normal resolution (K=2), the control circuit 36 discriminates if an 
EOL-MR is detected between one EOL-MH and a next EOL-MH or not. The 
control circuit 36 counts the numbers of EOL-MRs detected by the EOL-MR 
detecting circuit 30 during a period which is from a detection of one 
EOL-MH to a detection of the next EOL-MH to give a count value S. In the 
case of the MR mode at the normal resolution (K=2), one line of MH codes 
and one line of MR codes alternately are received. Therefore, if the count 
value S is "1", the control circuit 36 increments a count value a, and if 
the count value S is not "1", the control circuit 36 increments a count 
value b. When the RTC is detected by the RTC detecting circuit 35, the 
control circuit 36 compares b/(a+b) with a predetermined value c. In the 
case of b/(a+b).ltoreq.c, the control circuit 36 determines that the 
received image data corresponding to one page has been of fine quality, 
and in the case of b/(a+b)&gt;c, the control circuit 36 determines that the 
received image data corresponding to one page has not been of fine 
quality. 
In the case where the facsimile apparatus receives image data in a MR mode 
at the fine resolution (K=4), the control circuit 36 discriminates if the 
count value S is "3" or not. If the count value S is "3", the control 
circuit 36 increments the count value a, and if the count value S is not 
"3", the control circuit 36 increments the count value b. 
In the case where the facsimile apparatus receives image data in a MR mode 
at the super-fine resolution (K=8), the control circuit 36 discriminates 
if the count value S is "7" or not. If the count value S is "7", the 
control circuit 36 increments the count value a, and if the count value S 
is not "7", the control circuit 36 increments the count value b. 
The control circuit 36 determines the quality of the received data 
corresponding to one page in the manner mentioned above, and then sends a 
response signal corresponding to the result of the determination in 
response to a signal in a Q signal from a transmitting station. 
The Q signal is MPS (Multi-Page Signal), EOM (End of Message), or EOP (End 
of Procedure), and the response signal is MCF (Message Confirmation) or 
RTN (Retain Negative), etc. 
Next, the receiving operation of this embodiment is explained as follows. 
FIGS. 2 through 4 together form a flow-chart showing a method of 
controlling processes by the control circuit 36. 
The control circuit 36 initializes the relay CML of the NCU2 to connect the 
telephone line 2a to the telephone 4 by setting the signal line 36a to be 
"0" (S1). The control circuit 36 discriminates if image reception has been 
selected or not (S2). If image reception has not been selected, the 
control circuit 36 effects other processes (S3), and then returns to step 
S1. 
If image reception has been selected, the control circuit 36 turns on the 
relay CML of the NCU2 by setting the signal line 36a to be "1" so as to 
connect the telephone line 2a to the facsimile terminal (S4). Then the 
control circuit 36 effects a pre-procedure for setting a communication 
mode (S5), and discriminates whether G3 image reception or an ECM (Error 
Correction Mode) image reception has been selected in the pre-procedure 
(S6). If ECM image reception has been selected, the control circuit 36 
effects the ECM image reception, and records received image data (S7), and 
then returns to step S1. In the ECM image reception, image data is 
communicated by using a HDLC (High-level Data Link Control) format. 
Therefore, the control circuit 36 detects communication errors by checking 
specific flags according to the HDLC format without decoding the received 
image data in the ECM image reception. 
In the case where G3 image reception has been selected in step S6, the 
control circuit 36 analyzes a FIF (Facsimile Information Field) of DCS 
(Digital Command Signal) received in the pre-procedure, and stores 
information, which indicates a coding mode and which is discriminated by 
the analysis, into an internal memory of the control circuit 36 (S8). The 
coding mode can be the MH mode, the MR mode, or a MMR (Modified Modified 
READ) mode, etc. Then the control circuit 36 analyzes a FIF of NSS 
(Non-Standard Set-up)/TSI (Transmitting Subscriber Identification) 
received in the pre-procedure, and stores information, which indicates a 
transmission mode and which is discriminated by the analysis, into the 
internal memory (S9). The information of the transmission mode includes 
resolution information (normal resolution, fine resolution, or super-fine 
resolution), etc. 
The control circuit 36 completes the pre-procedure (S10), and them 
initializes the internal counters a and b (S11). The counter a is a 
counter for counting the number of times a correct number of EOL-MRs is 
detected between one EOL-MH and the next EOL-MH, and the counter b is a 
counter for counting the number of times an incorrect number of EOL-MRs is 
detected between one EOL-MH and the next EOL-MH. 
Next, the control circuit 36 stores the demodulated image data into the 
memory circuit 22 (S12), and discriminates if an EOL-MH is detected by the 
EOL-MH detecting circuit 28 or not (S13). In the case where an EOL-MH is 
not detected, the control circuit 36 discriminates if an RTC is detected 
by the RTC detecting circuit 35 or not (S14). In the case where the RTC is 
detected, the control circuit 36 shifts from step S14 to step S41 of FIG. 
4. In the case where an RTC is not detected, the control circuit 36 
performs a recording operation of FIG. 6 (S15), and then returns to step 
S12. 
On the other hand, in the case where the EOL-MH is detected in step S13, 
the control circuit 36 discriminates (FIG. 3) whether the coding mode is 
the MH mode or the MR mode (S21). In the case where the coding mode is the 
MR mode, the control circuit 36 clears the counter s (S22), and then 
shifts to step S24. The counter s is an internal counter of the control 
circuit 36 for counting the number of EOL-MRs. In the case where the 
coding mode is the MH mode, the control circuit 36 starts the count 
operation of the counter 34 (S23), and then shifts to step S24. 
The control circuit 36 stores the demodulated image data (the received 
image data) into the memory circuit 22 (S24), and discriminates if an 
EOL-MR is detected by the EOL-MR detecting circuit 30 or not (25). In the 
case where the EOL-MR is detected, the control circuit 36 increments the 
count value S of the counter s (S26), and then returns to step S24. On the 
other hand, in the case where an EOL-MR is not detected, the control 
circuit 36 discriminates if an EOL-MH is detected or not (S27). In the 
case where the EOL-MH is detected, the control circuit 36 performs a 
determining operation of FIG. 5 (S28), and then returns the step S21. On 
the other hand, in the case where an EOL-MH is not detected in step S27, 
the control circuit 36 discriminates if the RTC is detected or not (S29). 
In the case where the RTC is detected, the control circuit 36 shifts from 
step S29 to step S41 of FIG. 4. On the other hand, in the case where an 
RTC is not detected, the control circuit 36 performs the recording 
operation of FIG. 6 (S30), and then returns to step S24. 
In the case where the RTC is detected in step S15 or step S29, the control 
circuit 36 performs an intermediate procedure for informing the 
transmitting station of the quality of the received image data (S41), and 
then waits to receive the Q signal (MPS, EOM, or EOP) in step S42. After 
receiving the Q signal, the control circuit 36 compares b/(a+b) with a 
predetermined value c (S43). In the case of b/(a+b).ltoreq.c, the control 
circuit 36 sends the MCF to the transmitting station (S44). On the other 
hand, in the case of b/(a+b).gtoreq.c, the control circuit 36 sends the 
RTN to the transmitting station (S45). 
Next, the control circuit 36 discriminates if there is data corresponding 
to a next page to be received (S46). In the case where there is data of 
the next page, the control circuit 36 completes the intermediate procedure 
(S47), and then returns to step S11. On the other hand, in the case where 
there is no data of a next page, the control circuit 36 performs an end 
procedure (S48), and then initializes the relay CML of the NCU2 (S49). 
Next, the control circuit 36 discriminates if there is received image data 
to be recorded (S50). In the case where there is received image data to be 
recorded, the control circuit 36 causes the recording unit 26 to record 
the received image data stored in the memory circuit 22 page by page 
(S51). In the case where all the received image data has been recorded, 
the control circuit 36 returns to step S1 of FIG. 2. 
In step S41, step S44, step S45, step S47, and step S48 of FIG. 4, the 
control circuit 36 performs the above mentioned process and the recording 
operation (FIG. 6) as follows. 
FIG. 5 is a flow chart showing the "determining" subroutine for determining 
whether the number of EOL-MRs is correct for a particular interval. In 
FIG. 5, the control circuit 36 discriminates whether the coding mode is 
the MH mode or the MR mode (S61). In the case where the coding mode is the 
MH mode, i.e. the one-dimensional mode, the control circuit 36 checks if a 
count value of the counter 34 (number of bits of decoded image data) is a 
predetermined value or not (S66). The predetermined value corresponds to 
the fixed number of pixels of one line (e.g. in case of A4 size: 1,728, in 
case of B4 size: 2,048). When the count value of the counter 34 is the 
predetermined value in step S66, the control circuit 36 increments the 
internal counter a (S67) (i.e. correct), and then returns to the main flow 
chart shown in FIG. 2 through FIG. 4. On the other hand, when the count 
value of the counter 34 is not the predetermined value in step S66, the 
control circuit 36 increments the internal counter b (S68) (i.e. 
incorrect), and then returns to the main flow chart. 
On the other hand, in the case where the coding mode is the two-dimensional 
MR mode, the control circuit discriminates whether the resolution of the 
transmitting mode is the normal resolution, fine resolution, or super-fine 
resolution (S62). In the case where the resolution of the transmitting 
mode is the normal resolution, the control circuit 36 discriminates if the 
count value of the counter s is "1" or not (S65). In the case where the 
resolution of the transmitting mode is the fine resolution, the control 
circuit 36 discriminates if the count value of the counter s is "3" or not 
(S64). In the case where the resolution of the transmitting mode is the 
superfine resolution, the control circuit 36 discriminates if the count 
value of the counter s is "7" or not (S63). When the count value of the 
counter s is the correct value ("1", "3" or "7") in step S63, step S64 or 
step S65, the control circuit 36 increments the internal counter a (S67). 
On the other hand, when the count value of the counter s is not the 
correct value ("1", "3" or "7"), the control circuit 36 increments the 
internal counter b (S68). Then the control circuit 36 returns to the main 
flow. 
FIG. 6 is a flow chart showing a "recording" subroutine. In FIG. 6, the 
control circuit 36 discriminates whether the received image data 
corresponding to at least one page has been stored in the memory circuit 
22 or not (S71). In the case where the received image data of at least one 
page has been stored in the memory circuit 22, the control circuit 36 
causes the recording unit 26 to record the stored image data in page 
units, i.e. page by page (S72), and then returns to the main flow of FIG. 
2 through FIG. 4. In the recording operation mentioned above, the decoding 
unit 24 decodes the received image data from the memory circuit 22, and 
sends decoded image data to the recording unit 26. The recording unit 26 
records the decoded image data at the fixed speed. In this embodiment, the 
image data is continuously received, and the received image data is stored 
in the memory circuit 22, and then the stored image data is recorded by 
the recording unit 26. The facsimile apparatus according to the first 
embodiment mentioned above can determine the quality of the received MR 
coded image data, by the combination of the detection of the EOL-MH, the 
detection of the EOL-MR, and the MH decoding operation, without decoding 
the MR coded image data according to the MR decoding method. 
Further, in the facsimile apparatus according to the first embodiment, the 
structure of decoding the MR codes is simpler and cheaper than the one of 
the prior art. 
Further, as above mentioned, the predetermined value c in step S43 of FIG. 
4 is fixed regardless of the resolution (K=2, 4, 8). But the predetermined 
value c might be modified to be changed corresponding to each resolution 
(K=2, 4, 8) of image data. In the first embodiment, the parameter K of the 
MR coding method is previously set in accordance with the resolution of 
image data (i.e. normal resolution: K=2, fine resolution: K=4, super-fine 
resolution: K=8). However, this parameter might be modified to be set in 
the pre-procedure. 
Next, a facsimile apparatus according to a second embodiment of the present 
invention will be described as follows. The facsimile apparatus according 
to the second embodiment detects the EOL-MH and the EOL-MR, and further 
checks the number of bits of one decoded line of the MH codes. Then the 
apparatus determines the quality of the received image data in accordance 
with the number of the EOL-MRs and the number of bits of the decoded line 
of the MH codes. 
The structure of the facsimile apparatus according to the second embodiment 
is similar to FIG. 1, but the control circuit 36 performs a different 
control operation in the second embodiment. The control circuit 36 counts 
the numbers of the detected EOL-MRs and checks this count value in 
response to the detection of the EOL-MH in the same manner as the first 
embodiment. Further, the control circuit 36 checks whether the count value 
of the counter 34 (the number of bits of one decoded line of the MH codes) 
is the predetermined value (e.g. A4 size: 1728, B4 size: 2048, etc.) or 
not. Then the control circuit 36 counts the number d of lines having the 
predetermined value and the number e of lines not having the predetermined 
value. Then the control circuit compares b/(a+b) with a predetermined 
value c, and further compares e/(d+e) with a predetermined value f in 
response to a detection of the RTC. In the case of either b/(a+b)&gt;c or 
e/(d+e)&gt;f, the control circuit 36 determines that the quality of the 
received image data is bad. In the case of b/(a+b).ltoreq.c and 
e/(d+e).ltoreq.f, the control circuit 36 determines that the quality of 
the received image data is good. 
FIG. 7 through FIG. 10 together form a flow chart showing a control 
operation of the control circuit 36 in the second embodiment. FIG. 7, FIG. 
8, FIG. 9 and FIG. 10 correspond to FIG. 2, FIG. 3, FIG. 4 and FIG. 5, 
respectively. In FIG. 7 through FIG. 10, the steps which involve same 
operations as FIG. 2 through FIG. 5 are identified with the same numbers, 
and explanations thereof are omitted. 
In step S111 of FIG. 7, the control circuit 36 initializes internal 
counters a, b, d and e. The internal counter a is a counter which counts 
the number of detections of the correct number of EOL-MRs between one 
EOL-MH and the next EOL-MH. The internal counter b is a counter which 
counts the number of detections of an incorrect number of EOL-MRs between 
one EOL-MH and the next EOL-MH. The internal counter d is a counter which 
counts the number of lines (lines of MH codes) having the correct number 
of bits, and the internal counter e is a counter which counts the number 
of lines (lines of MH codes) having the incorrect number of bits. 
In FIG. 8, the control circuit 36 performs step S22 and step S23 
irrespective of the coding mode. 
In step S43 of FIG. 9, the control circuit 36 compares b/(a+b) with the 
predetermined value c. In the case of b/(a+b).ltoreq.c, the control 
circuit 36 shifts from step S143 to step S144. In the case of b/(a+b)&gt;c, 
the control circuit 36 shifts from step S43 to step S45. In step S143, the 
control circuit 36 compares e/(d+e) with the predetermined value f. In the 
case of e/(d+e).ltoreq.f, the control circuit 36 shifts from step S143 to 
step S44. In the case of e/(d+e)&gt;f, the control circuit 36 shifts to step 
S45. 
In step S66 of FIG. 10, the control circuit 36 discriminates if the count 
value of the counter 34 is the predetermined value or not. 
In the case where the count value of the counter 34 is the predetermined 
value, the control circuit 36 increments the internal counter d in step 
S168. In the case where the count value of the counter 34 is not the 
predetermined value, the control circuit 36 increments the internal 
counter e in step S167. After step S167 or step 168, the control circuit 
36 shifts to step S62. The predetermined value is, for example 1,728 for 
A4 paper and 2,048 for B4 paper. 
The facsimile apparatus according to the second embodiment is able to 
determine the quality of the received image data more accurately than one 
according to the first embodiment. 
Next, a facsimile apparatus according to a third embodiment will be 
described as follows. 
FIG. 11 is a block diagram of the facsimile apparatus according to the 
third embodiment. In FIG. 11, the circuits which have the same functions 
as in FIG. 1 are identified with the same number, and explanations thereof 
are omitted. 
A memory circuit 13 is provided for storing the coded data from the coding 
circuit 12 and outputting the stored data to a size modifying circuit 15 
in accordance with a control signal from the control circuit 36. 
The size modifying circuit 15 is provided for modifying a size of a main 
scanning direction of the coded data. The size modifying circuit 15 
decodes the coded data, modifies the size of the decoded data, recodes the 
modified data, and then outputs the recoded data to the modulator 14. The 
modulator 14 selectively modulates the coded data from the coding circuit 
12 or the coded data from the size modifying circuit 15 in accordance with 
a control signal from the control circuit 36. 
Numeral 37 denotes a direct transmission button by which an operator 
manually selects a direct transmission mode. 
A direct transmission lamp 38 is provided for indicating that the direct 
transmission mode is selected. 
The direct transmission lamp 38 is turned off by a control pulse from the 
control circuit 36. The direct transmission lamp 38 sets a signal line 38a 
to be "1" while the lamp 38 is turned on, and sets the signal line 38a to 
be "0" while the lamp 38 is turned off. 
An error page information generating circuit 39 is provided for generating 
information of error pages and outputting the information of error pages 
to the recording unit 26 line by line in response to a control signal from 
the control circuit 36. The error page information generating circuit 39 
outputs a pulse to the control circuit 36 when the circuit 39 finishes 
outputting the information of error pages to the recording unit 26. 
In the case where the facsimile apparatus receives image data which is not 
in the HDLC format, the control circuit 36 causes the memory circuit 22 to 
store one page of received image data, and then performs a process of 
checking for an error of the previous page stored in the memory circuit 22 
and a process of recording the previous page while the control circuit 36 
causes the memory circuit 22 to store a next page of received image data. 
The control circuit 35 sends information of the quality of the previous 
page to a destination (a transmitting machine) after finishing checking 
for an error of the previous page and finishing receiving the next page. 
Then, the control circuit 36 sends information of the quality of an end 
page to the destination after decoding the end page and checking for an 
error of the end page and finishing recording the end page. 
Next, a control operation of the control circuit 36 according to the third 
embodiment in image reception will be described as follows. 
FIG. 12 through FIG. 17 together form a flow chart showing the control 
operation of the control circuit 36. 
The control circuit 36 initializes the relay CML of the NCU2 (S201), sets 
the modulator 14 to input the coded data from the coding circuit 12 
(S202), initializes the recording unit 26 (S203), and then turns off the 
direct transmission lamp 38 (S204). 
The control circuit 36 discriminates whether image transmission or image 
reception has been selected (S205). In the case where the image 
transmission has been selected, the control circuit 36 discriminates 
whether the direct transmission mode has been selected or not (S206). If 
the direct transmission mode has been selected, the control circuit 36 
performs a control operation of direct transmission (FIG. 15) in step 
S207, and then return to step S201. If the direct transmission mode has 
not been selected, the control circuit 36 performs another process (S208), 
and then returns to step S201. 
On the other hand, in the case where the image reception mode has been 
selected, the control circuit 36 turns on the CML relay of the NCU 2 
(S209), and performs a pre-procedure 1 by which the facsimile apparatus 
sets a communication mode (S210). In the pre-procedure 1, the facsimile 
apparatus informs the destination of information indicating what functions 
the facsimile apparatus has (including a function according to the third 
embodiment which is to inform the destination of the quality of the 
previous page after receiving the next page). 
In step S211, the control circuit 36 discriminates whether ECM (Error 
Correction Mode) communication or G3 communication has been selected in 
the pre-procedure. IN the case where ECM communication has been selected, 
the control circuit 36 performs a process of ECM reception/recording 
(S212), and then returns to step S201. On the other hand, in the case 
where G3 communication has been selected, the control circuit 36 
discriminates whether the destination (the transmitting machine) has a 
function which corresponds to the function of informing the quality of the 
previous page at the end of receiving the next page or not (S213), i.e. 
whether it can respond to this information. If the destination has the 
function, the control circuit 36 performs a receiving operation 1 of FIG. 
13 (S214) and then returns to step S201. If the destination does not have 
the function, the control circuit 36 performs a receiving operation 2 of 
FIG. 14 (S215), and then returns to step S201. 
Next, the receiving operation 1 will be described as follows. 
In step S221 of FIG. 13, the control circuit 36 performs a pre-procedure 2. 
The pre-procedure 2 is a process following the pre-procedure 1 of step 
S210. Then the control circuit 36 allows the recording unit 26 to record 
received image data (S222), and initializes an internal page counter 
(S223). The control circuit 36 stores received image data into the memory 
circuit 22 (S224), and discriminates if image data corresponding to one 
page has been received or not (S225). The control circuit 36 performs the 
process of steps S224 and steps S225 until image data corresponding to one 
page has been received. 
After image data corresponding to one page has been received, the control 
circuit 36 performs an intermediate procedure 1a (S226). In the 
intermediate procedure 1a, the control circuit 36 does not inform the 
destination of information of the quality of the received image data. 
Next, the control circuit 36 discriminates if image data corresponding to a 
next page will be received or not (S227). In the case where image data 
corresponding to the next page will be received, the control circuit 36 
performs an intermediate procedure 2 (S228). The intermediate procedure 2 
is a process following the intermediate procedure 1a of step S226. Then 
the control circuit 36 increments the internal page counter (S229), stores 
received image data into the memory circuit 22 (S230), causes the decoding 
circuit 24 to decode the coded image data corresponding to the previous 
page and causes the recording unit 26 to record decoded image data at a 
fixed speed while it performs a process of checking for an error (S231). 
The previous page is a page corresponding to a value which is 1 less than 
the count value of the internal page counter. 
Then, the control circuit 36 discriminates if image data corresponding to 
one page has been received or not (S232). In the case where image data 
corresponding to one page has not been received, the control circuit 36 
shifts from step S232 to step S231. In the case where image data 
corresponding to one page has been received, the control circuit 36 
performs an intermediate procedure 1b (S233). In the intermediate 
procedure 1b, the control circuit 36 informs the destination of 
information of the quality of the previous page in accordance with the 
result of checking for an error in step S231. 
On the other hand, in the case where image data corresponding to a next 
page is not to be received, the control circuit 36 causes the decoding 
circuit 24 to decode the coded image data corresponding to an end page and 
causes the recording unit 26 to record the decoded image data and performs 
the process of checking for an error (S234). 
Next, the control circuit 36 performs an end procedure (S235), and then 
returns to step S201 of FIG. 12. In the end procedure, the control circuit 
36 informs the destination of information of the quality of the end page 
in accordance with the result of checking for an error. 
Next, the receiving operation 2 will be described as follows. 
In step S241 of FIG. 14, the control circuit 36 performs the pre-procedure 
2. Then the control circuit 36 allows the recording unit 26 to record 
received image data (S242), and initializes the internal page counter 
(S243). The control circuit 36 stores received image data into the memory 
circuit 22 and performs the process of checking for an error (S244), and 
discriminates whether image data corresponding to one page has been 
received or not (S245). The control circuit 36 performs the process of 
step S244 until image data corresponding to one page is received. 
In the case where the image data corresponding to one page has been 
received, the control circuit 36 performs an intermediate procedure 1 
(S246). In the intermediate procedure 1, the control circuit 36 informs 
the destination of information of the quality of the received page in 
accordance with a result of checking for an error in step S244. 
Then the control circuit 36 discriminates whether image data corresponding 
to a next page will be received or not (S247). In the case where the image 
data corresponding to the next page will be received, the control circuit 
36 performs an intermediate procedure 2 (S248). The intermediate procedure 
2 is a process following the intermediate procedure 1 of step S246. 
Next, the control circuit 36 increments the internal page counter (S249), 
and then stores received image data into the memory circuit 22 and checks 
if the received image data includes error data or not (S250). Then, the 
control circuit 36 causes the recording unit 26 to record the image data 
corresponding to the previous page in the memory circuit 22 (S251), and 
discriminates whether image data corresponding to one page has been 
received or not (S252). In the case where the image data corresponding to 
one page has been received, the control circuit 36 shifts from step S252 
to step S246. In the case where image data corresponding to one page has 
not been received, the control circuit 36 shifts from step S252 to step 
S250. 
On the other hand, in the case where image data corresponding to a next 
page is not to be received, the control circuit 36 performs an end 
procedure (S253), and turns off the CML relay of the NCU2 (S254). 
The control circuit 36 causes the decoding circuit 24 to decode the coded 
image data corresponding to the end page, causes the recording unit 26 to 
record decoded image data (S255), and then returns to step S201 of FIG. 
12. 
Next, the process of the direct transmission of step S206 will be described 
in detail as follows. 
In step S261 of FIG. 15, the control circuit 36 turns on the CML relay of 
the NCU 2. Then, the control circuit 36 performs a pre-procedure 1 (S262), 
and discriminates whether a communication protocol to be effected is the 
G3 mode or the ECM mode (S263). In the case where the communication 
protocol is the ECM mode, the control circuit 36 performs processes of 
reading and transmitting image data according to the ECM mode (S267), and 
then returns to step S201 of FIG. 12. 
On the other hand, in the case where the communication protocol is the G3 
mode, the control circuit 36 discriminates whether a destination (a 
receiving machine) has a function corresponding to the third embodiment or 
not (S264). If the destination has the function, the control circuit 36 
performs a transmitting operation of FIG. 16 (S265), and then returns to 
step S201 of FIG. 12. If the destination does not have the function, the 
control circuit 36 performs a transmitting operation 2 of FIG. 17 (S266), 
and then returns to step S201 of FIG. 12. 
Next, the transmitting operation 1 will be described as follows. 
In step S271 of FIG. 16, the control circuit 36 performs a pre-procedure 2. 
The pre-procedure 2 is a process following the pre-procedure 1 of step 
S262. 
The control circuit 36 initializes the internal page counter (S272), and 
then causes the reading unit 10 to read an image of a document set in the 
reading unit 10 and transmits the image data read by the reading unit 10 
to the destination (S274). The control circuit 36 discriminates whether 
image data of one page has been transmitted or not (S274). If image data 
of one page has not been transmitted, the control circuit 36 continues to 
transmit read image data. If image data of one page has been transmitted, 
the control circuit 36 discriminates whether a next page is set in the 
reading unit 10 or not (S275). In the case where a next page is not set, 
the control circuit 36 performs an end procedure (S280), and then returns 
to step S201 of FIG. 12. In the case where the next page is set, the 
control circuit 36 discriminates whether the count value of the internal 
page counter is "1" or not (S276). If the count value of the internal page 
counter is "1", the control circuit 36 performs an intermediate procedure 
A (S277). If the count value of the internal page counter is not "1", the 
control circuit 36 performs an intermediate procedure B (S278). The 
control circuit 36 increments the internal page counter (S279), and then 
returns to step S273. In the intermediate procedure A of step S277, the 
control circuit 36 does not receive information of the quality of 
transmitted image data from the destination. In the intermediate procedure 
B of step S278, the control circuit 36 receives information of the quality 
of transmitted image data from the destination, and stores the received 
information and data of the page number (equal to the count value of the 
internal page counter minus 1) into an internal memory of the control 
circuit 36. 
In the end procedure of step S280, the control circuit 36 waits for 
information of the quality of transmitted image data from the destination 
to be received, and stores the information and the page number 
corresponding to the information into the internal memory of the control 
circuit 36. 
Next, the transmitting operation 2 will be described as follows. 
In step S291 of FIG. 17, the control circuit 36 performs the pre-procedure 
2. The control circuit 36 initializes the internal page counter (S292), 
and then causes the reading unit 10 to read the document set in the 
reading unit 10 and transmits the image data read by the reading unit 10 
to the destination (S293). The control circuit 36 discriminates whether 
image data of one page has been transmitted or not (S294). In the case 
where the image data of one page has been transmitted, the control circuit 
36 discriminates whether a next page is set in the reading unit 10 or not 
(S295). In the case where the next page is set, the control circuit 36 
performs an intermediate procedure (S296), increments the internal page 
counter (S297), and then returns to step S293. In the case where a next 
page is not set, the control circuit 36 performs an end procedure (S298), 
and then returns to step S201 of FIG. 12. 
In the intermediate procedure of step S296 and the end procedure of step 
S298, the control circuit 36 waits for information of the quality of 
transmitted image data from the destination to be received, and stores the 
information and the page number corresponding to the information (the 
count value of the internal page counter) into the internal memory of the 
control circuit 36. 
In the case where the facsimile apparatus performs the transmitting 
operation mentioned above, the control circuit 36 uses the information 
stored in the internal memory of the control circuit 36 when the apparatus 
prints a report of a communication result, etc. 
As above mentioned, the facsimile apparatus according to the third 
embodiment determines the quality of received image data in accordance 
with decoded image data for recording, and informs the destination of a 
result of determining after receiving image data of the next page. Thereby 
the facsimile apparatus does not need to decode received image data for 
determining the quality, and only decodes the received image data for 
recording. 
In the third embodiment mentioned above, the facsimile apparatus finishes 
recording image data of the previous page before finishing receiving image 
data of one page. But the facsimile apparatus according to the third 
embodiment might finish receiving image data of one page before finishing 
recording image data of the previous page. 
In the third embodiment mentioned above, the facsimile apparatus informs 
the destination of information of the quality of received image data at 
the time it finishes receiving image data of one page. But the facsimile 
apparatus according to the third embodiment might inform the destination 
of information of the quality of all the received image data after 
finishing receiving the image data of the end page. This is accomplished 
by modifying the control operation shown in FIG. 13 and FIG. 16 as 
follows. 
(1) In the intermediate procedure 1b of step S233 of FIG. 13, the control 
circuit 36 does not inform the destination of the information of the 
quality. 
(2) In the end procedure of step S235 of FIG. 13, the control circuit 36 
informs the destination of information of the quality of all pages. 
(3) The process of step S276 and the process of step S278 in FIG. 16 are 
deleted. 
(4) In the end procedure of step S280 of FIG. 16, the control circuit 36 
waits for information of the quality corresponding to all pages to be 
received, and stores the information and data of the page number into the 
internal memory of the control circuit 36. 
In the case where a memory transmission is selected, the facsimile 
apparatus keeps the read image data in the memory circuit 13 and resends 
image data of the memory circuit 13 corresponding to data of an error page 
from the destination. 
Further, the facsimile apparatus according to the third embodiment might 
add a message for indicating an error page, which is edited by the 
generating circuit 39, to recorded image data of the error page. 
Further, the facsimile apparatus according to the present invention might 
be structured as plural devices or as one apparatus. 
Further, the present invention is applicable to a system or an apparatus, 
to which a program for controlling is supplied. 
Although particular embodiments of the present invention are herein 
disclosed for purposes of explanation, various modification thereof, after 
study of this specification, will be apparent to those skilled in the art 
to which the invention pertains.