JP3384636B2 - Image communication device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image communication device for transmitting / receiving image information via a wireless line.

[0002]

2. Description of the Related Art Conventionally, an image communication apparatus such as a wireless facsimile apparatus for transmitting and receiving image information by utilizing a wireless line as a part of a transmission line has been put into practical use. The wireless facsimile device is configured, for example, by directly connecting a small facsimile device to a car phone, a mobile phone, or the like with a wired cable, or by mounting a wireless function or the like in the main body of the facsimile device as long as it is within an area where wireless radio waves reach. , It is possible to send and receive image information without being fixed to a specific place.

However, while this wireless facsimile apparatus is not fixed in the place of use, it is easily affected by communication interference due to changes in the state of radio waves (interference, fading, etc.), and the use while moving, that is, the state of radio waves is momentary. Under such a changing condition, there is a problem that the transmission and reception of the signal becomes unstable and the image is greatly disturbed, or the transmission is not completed promptly due to the continuous repetition of the retransmission.

Therefore, as a solution to these problems, at the start of communication, the quality of the radio wave is detected from the training signal between the modems, which is carried out between the transmitting side facsimile apparatus and the receiving side facsimile apparatus, and the result is detected. A technique for changing the transmission condition according to the method (for example, Japanese Patent Laid-Open No. 63-63).
No. 240) or a technique for ensuring strong transmission against radio interference using a unique communication protocol between the radio base station and the radio facsimile device when the radio wave condition is poor (for example, Japanese Patent Laid-Open No. 6-225111). Is proposed.

[0005]

However, in the case of transmitting image information using the conventional technique under bad radio wave conditions, any technique requires a unique communication protocol. There is a problem that efficient transmission cannot be secured for the terminal. The present invention has been made in view of such a point, and by reducing and converting image data according to the state of the radio wave between the wireless base station and the mobile station, the data can be obtained even when the radio wave state is bad. The present invention aims to provide an image communication terminal excellent in operability and economical efficiency that can promptly end the transmission and reception of the image.

[0006]

According to a first aspect of the present invention, in an image communication apparatus for transmitting and receiving image information via a wireless line, a radio wave state determining means for determining a radio wave state of the wireless line, and the radio wave state determining means. Image processing means for performing reduction conversion processing on the image information when the means determines that the state of the radio wave is poor.

According to a second aspect of the present invention, in an image communication apparatus for transmitting and receiving image information via a wireless line, a state of a radio wave is judged by a radio wave state judging means for judging a radio wave state of the wireless line. An image processing unit that performs reduction conversion processing on the image information when it is determined to be defective, and when a predetermined process is performed by the image processing unit, the fact is inserted as a message in the image and the recipient is notified. And a processing notification means.

According to a third aspect of the present invention, in an image communication apparatus for transmitting and receiving image information via a wireless line, a radio wave state judging means for judging a radio wave state of the wireless line, and a radio wave state judging means for detecting a radio wave state. When it is determined that the state is bad, a predetermined line of image information is replaced with an all-white line. According to a fourth aspect of the present invention, in an image communication device for transmitting and receiving image information via a wireless line, a detection result of a level detection means for detecting a reception level of a received radio wave and a noise detection means for detecting a noise figure of external noise. A radio wave state determination means for determining whether the radio wave state is good or bad based on the detection result, and an image processing means for performing reduction conversion processing on the image information when the radio wave state determination means determines that the radio wave state is poor It is a thing.

According to a fifth aspect of the present invention, in the image communication device for transmitting and receiving image information via a wireless line, the frequency of retransmission occurrences of the retransmission detecting means for detecting the occurrence of error retransmission of information transmitted and received on the wireless line. According to the radio wave condition judging means for judging whether the radio wave condition is good or not, and the image processing means for performing reduction conversion processing on the image information when the radio wave condition judging means judges that the radio wave condition is poor. is there.

[0010]

According to the present invention, the radio wave condition of the wireless line is judged by the radio wave condition judging means, and when the radio wave condition judging means judges that the radio wave condition is bad, the image processing means reduces the image information. Apply conversion processing to image information. According to claim 2, the radio wave state of the wireless line is determined by the radio wave state determining means, and when the radio wave state determining means determines that the radio wave state is poor, the image processing means performs reduction conversion processing on the image information. The information is applied to the image information, and the processing notification means inserts it as a message in the image to notify the recipient.

According to a third aspect of the present invention, the radio wave state of the wireless line is determined by the radio wave state determining means, and when the radio wave state determining means determines that the radio wave state is poor, the image processing means determines a predetermined value of the image information. Replace the line with a white line. According to claim 4, the level detecting means detects the reception level of the received radio wave, the noise detecting means detects the noise figure of the external noise, and the radio wave state determining means detects the detection result of the level detecting means and the noise detecting means. Based on the result, it is determined whether or not the state of the radio wave is good, and when it is determined that the state of the radio wave is bad, the image processing unit performs reduction conversion processing on the image information.

In the present invention, the retransmission detecting means detects the occurrence of error retransmission of the information transmitted and received on the wireless line, and the radio wave condition judging means detects the occurrence of the radio wave according to the frequency of the retransmission detected by the retransmission detecting means. The quality of the state is determined, and when it is determined that the state of the radio wave is poor, the image processing unit performs reduction conversion processing on the image information.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image communication apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9 by taking a facsimile apparatus having a wireless function as an example. First, as a first embodiment, an embodiment in which the present invention is applied to a wireless facsimile machine will be described.

FIG. 1 is a schematic block diagram of a wireless facsimile apparatus according to an embodiment of the image communication apparatus of the present invention. In FIG. 1, MF is a wireless facsimile machine, which is
Through the radio wave P, the radio base station BS, and the public network N, it is connected to the facsimile machine FF on the other side.

The wireless facsimile apparatus MF has an antenna 5
The radio IF circuit 4 for performing radio communication with the radio base station BS via the radio wave, the radio wave state monitor circuit 9 as radio wave state monitoring means for monitoring the state of the radio wave P by a method described later, and the radio wave state monitor circuit 9 A conversion processing control circuit 8 for controlling an encoding circuit 2 which will be described later on the basis of the monitoring information, and a document to be transmitted are optically read from a scanner or the like, or are created on a computer and input as digital image information. An image input circuit 1 for performing the predetermined encoding or processing on the image information input by the image input circuit 1 according to an instruction from the conversion processing control circuit 8; A communication control circuit 3 for intermediating and controlling a facsimile communication protocol and a wireless communication protocol, and a reception coded image received from the wireless IF circuit 4 via the communication control circuit 3. A decoding circuit 7 for decoding the information,
An image output circuit 6 is provided for displaying or printing the image information decoded by the decoding circuit 7 and outputting the image information.
In this embodiment, the image information is input as digital image information by optically reading a document to be transmitted by the image input circuit 1 with a scanner or the like, or by creating it on a computer. It may be stored in advance in a memory such as, and the image information may be used as the input image information.

The case of transmitting image information to the fixed station facsimile apparatus FF via the radio base station BS and the public network N in such a configuration will be described. First, a case where the wireless signal transmitted and received between the wireless IF circuit 4 and the wireless base station BS is an analog system will be described as an example. FIG. 2 is a schematic configuration diagram of the radio wave state monitoring circuit 9 when the analog method is used. FIG. 3 is a diagram sequentially showing messages transmitted and received between the wireless facsimile apparatus of the present invention and the fixed station facsimile apparatus FF according to time. FIG. 4 is a flow chart for explaining the operation of the wireless facsimile machine of the present invention.

In FIG. 2, the radio wave condition monitoring circuit 9 includes a reception level detection circuit 21 for detecting the level value of the reception radio wave.
And a noise detection circuit 22 that detects the magnitude and frequency of noise contained in the reception channel, and a reception state determination circuit 23 that determines the quality of the radio wave based on the detection results of the reception level detection circuit 21 and the noise detection circuit 22. It has and. When transmitting image information from the wireless facsimile apparatus MF, a manuscript or the like is inserted into the image input circuit 1 and a fixed station facsimile apparatus FF which is a receiving terminal is input from an operation panel circuit (not shown).
Enter the dial number and press the start button (S4
01). Then, the communication control circuit 3 connected to the operation panel circuit controls the wireless IF circuit 4 to make the wireless base station B
S and the public network N are caused to set the wireless communication path, and the fixed station facsimile device FF is given a calling tone (CNG: 3).
01) is sent to request call setup (S402). On the other hand, in the fixed station facsimile apparatus FF on the receiving side, when the calling tone (CNG) is confirmed, the called station identification signal (CED: 302) is returned and responded, and the standard capability of the self apparatus is displayed. Digital identification signal (DIS:
303) is returned. The transmission side wireless facsimile apparatus MF (S404), which has confirmed this, compares the terminal capability of the communication control circuit 3 with its own capability to determine the maximum capability in common and determines the result as a digital transmission command ( DC
S: 304) and notify the receiving side terminal (S4)
05). After that, the transmitting side wireless facsimile apparatus MF
According to the capability value determined by the capability exchange in S404, the modem is switched to the high speed side and the training signal (TCF: 3
05) is transmitted (S406). If the training signal (TCF) is normally received by the receiving side, the receiving side returns a reception preparation confirmation (CFR: 306) and shifts to a communication state of image information.

In the image information communication state, the image information being input from the image input circuit 1 is sent to the encoding circuit 2 as digital image information. On the other hand, in the radio wave state monitoring circuit 9, the reception level detection circuit 21, the noise detection circuit 22, the radio wave state determination circuit 22 and the like constituting the radio wave state monitoring circuit 9 check the state of the radio wave P received from the radio base station BS by the radio IF circuit 4. It is continuously monitored (S407). Specifically, the reception level detection circuit 21 receives electric field strength (μ
V / m) and the external noise figure (E
N) and the like are measured, respectively, and the radio wave condition determination circuit 23 outputs the radio wave condition to the conversion processing control circuit 8 as "good" or "bad".

This judgment value is used until the communication is completed.
It is output to the conversion processing control circuit 8 each time a predetermined interval or a change in state occurs. In the conversion processing control circuit 8,
When the radio wave condition is “good”, the encoding circuit 2 is instructed to perform a normal encoding process (encoding by the encoding process method determined by the capability exchange. For example, MH encoding). If the radio wave condition is "bad" (S408), on the contrary, an instruction is given to execute a predetermined process instead of the normal process (S409).

Here, as an example of the predetermined processing in S409 when the radio wave state is "bad", a case where the normal encoding method is MH encoding will be described with reference to FIGS. . Figure 5 shows the normal state (the radio wave condition is "good")
In this case, the coding information obtained by the coding process (MH coding method) is shown.

The image information fetched from the image input circuit 1 is a main scanning direction in the case of using an A4 size original in a general G3 facsimile (in the facsimile scanning, the original to be transmitted is moved from the top to the bottom in the sub scanning direction). Then, black-and-white binary information of 1728 pixels is input in the main scanning for obtaining the grayscale information from left to right in the scanning line direction. In this case, black is read in a portion where there is a character and white is read in a portion where there is no character, resulting in a series of white pixels (white run: 501) and a series of black pixels (black run: 502). In the MH coding method, the continuous white run or black run is converted into a code value (allocated a short code to a run length having a high occurrence frequency) that is allocated in advance for each length (run length). . This conversion is performed for each line, and a line end code (EOL: 503) indicating the conversion is inserted at the line end.

FIG. 6 shows an encoding process when the state of the radio wave is "bad". The acquisition of image information and the number of pixels per line are the same as in the normal case of FIG. The difference is that in the image input circuit 1, 1 line, 2 lines, 3 ,. ． ． With respect to the data for each line that is sequentially captured, the original data is replaced with the all-white data and encoded every other line. That is, the image data is reduced and converted. In this embodiment, the original data is replaced with the all-white data every other line for encoding, but the present invention is not limited to this, and it may be every other line according to the radio wave condition.

As a result, when the radio wave condition is unstable, the amount of information can be suppressed and the communication can be terminated early. This processing is not particularly limited to MH encoding, and may be other encoding such as MR encoding. Regarding MR encoding, unlike MH encoding (one-dimensional encoding: independent encoding for each line), two-dimensional encoding (one basic line is processed by MH encoding and continued 1 or The three lines are coded with reference to the immediately preceding line, and this process is repeated thereafter), and therefore a different process from the above is required.

Specifically, even if a line to be two-dimensionally encoded is replaced with an all-white line forcibly subjected to one-dimensional encoding processing (by setting 1 to the tag bit in the synchronization code, Alternatively, instead of replacing with the all-white line, it is also possible to deal with the process by replacing with the code indicating the previous line and no change. That is, the image data is reduced and converted.

When the transmission of the captured image information is completed (S411), the encoding circuit 2 has a history of the radio wave condition being "bad" from the start of the transmission of the information to the end thereof. Whether or not it is confirmed (S412). This is done by confirming the setting of this flag when the information amount reduction process is performed in S409 (S410) and confirming the setting of this flag. A predetermined message telling that the message has been sent, for example, a message such as "The image density has been converted due to radio interference" is added to the end of the image, the line is disconnected, and the communication is terminated.

Next, a case where the radio signal transmitted and received between the radio IF circuit 4 and the radio base station BS is of a digital system will be described. It should be noted that here, description will be given of a method that is largely different from the case of the analog method, in particular, whether the radio wave condition is good or bad, and the conversion processing of image information and the like are similar to those of the analog method. FIG. 7 is a schematic configuration diagram of the radio wave state monitoring circuit 9 when the digital method is used. FIG. 8 shows a data retransmission transmission method (ARQ: Automatic Requests) used in digital facsimile communication.
It is a figure which shows the frame structure of t Error Control Scheme).

The frame structure shown in FIG. 8 is common to the transmitting side and the receiving side. The forward channel information 803
Is the main information such as image information, the forward channel control information 802 is the frame number, and the backward control information 801 is the response to the received information (normal reception: A
CK / abnormal reception: NACK), error detection codes for backward control information 801, forward channel control information 802, and forward channel information 803 are inserted in the CRC 804, respectively.

In FIG. 7, the radio wave condition monitoring circuit 9 includes an error resending detection circuit 71 for detecting the occurrence of an error resending request detected and controlled by the wireless IF circuit 4, and an error resending detection circuit 7
When the occurrence of erroneous retransmission is detected in step 1, the frequency is measured and the like, and the radio wave state determination circuit 72 that determines and outputs the radio wave state as “good” or “bad” is provided.

In the transmission state of image information, the image information input from the image input circuit 1 is encoded by the encoding circuit 2 and is transmitted to the facsimile apparatus on the other side via the communication control circuit 3 and the wireless IF circuit 4. It is being sent in sequence. This time,
The error resending detection circuit 71 monitors the occurrence of resending in the wireless IF circuit 4 (the wireless IF circuit 4 monitors the response signal from the receiving side, and performs resending processing when NACK is detected). This is transmitted to the radio wave condition monitoring circuit 72. The radio wave condition determination circuit 72 measures the frequency of re-transmissions, and when a predetermined threshold value such as a number of times or more within a predetermined time or a number of times in succession is exceeded, the radio wave condition is “bad”.
The conversion processing control circuit 8 is instructed to convert the image information. As a result, when the radio wave condition is very unstable and retransmissions occur frequently, it is possible to quickly end the communication. In the above description, the ACK / NAC from the receiving side is used.
Although the detection of K is used as the reference value for conversion processing execution, the CRC 804 in the received frame may be used as the reference value.

Next, as a second embodiment, an embodiment in which the present invention is applied to a radio base station will be shown. FIG. 9 is a schematic configuration diagram of a radio base station according to an embodiment of the image communication device of the present invention. In FIG. 9, BS is a radio base station and public network N
The fixed station facsimile machine FF connected to the
It connects to the facsimile device 92 connected to the first and the like. The radio base station BS has a radio IF circuit 93 that performs radio communication with the radio facsimile apparatus MF, a radio wave state monitoring circuit 94 that monitors the quality of the radio wave, and a radio wave state monitoring circuit 94 that indicates that the radio wave state is “bad”. Image data conversion circuit 95 for converting the image data when it is detected, an audio signal processing circuit 96 for converting an audio signal between the wireless system and the wired public network N, and a wired public line. And a line IF circuit 97 for interfacing.

With such a configuration, the fixed station facsimile apparatus FF is connected to the wireless facsimile apparatus MF via the public network N.
As a case where image information is transmitted to, a conversion process of image data different from that of the first embodiment will be described. In FIG. 9, when the image information is transmitted from the fixed station facsimile apparatus FF to the wireless facsimile apparatus MF,
The radio base station BS continuously monitors the radio wave state by the radio wave state monitoring circuit 94 via the wireless IF circuit 93. When it is determined that the radio wave condition is "bad", the image data conversion processing circuit 95 is instructed to convert the image information. The method of monitoring and determining the instruction here is the same as that of the first embodiment. Upon receiving the conversion instruction, the image data conversion processing circuit 95 causes the fixed station facsimile apparatus F via the line IF circuit 97.
The image information received from F indicates the end of the line "EO
The "L" code is detected, and the data up to the next "EOL" is replaced with all white line code data. As a result, the code amount can be reduced as in the first embodiment. In the case of MR coding or the like, it is possible to obtain the same effect by once decoding the coded image information, performing conversion processing, and then coding again.

In the above embodiments, one end is described as a wireless facsimile device and the other end is described as a fixed station facsimile device, but both ends may be wireless facsimile devices.

[0033]

According to the first aspect of the present invention, by continuously determining the radio wave condition and adjusting the data amount of the image information accordingly, the number of data error retransmissions can be reduced and the communication can be quickly terminated. It becomes possible and the communication cost can be reduced. According to claim 2, in addition to the effect of claim 1, when the image information is processed,
By providing the receiver of the data with the message indicating the execution of the process, the receiver can immediately know that the image received due to the radio wave condition is not a legitimate image.

According to a third aspect of the present invention, since the image data which has been subjected to the conversion processing is the conversion processing according to the regulation of the encoding system used in the facsimile, any facsimile apparatus conforming to the G3 standard can be used. Even a device can receive and reproduce. Claim 4 can be used for analog wireless communication.

Claim 5 can be used for digital wireless communication.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a wireless facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a radio wave state monitoring circuit according to an embodiment of the present invention.

FIG. 3 is a diagram showing a message sequence for explaining an operation according to an exemplary embodiment of the present invention.

FIG. 4 is a flowchart for explaining an operation according to an embodiment of the present invention.

FIG. 5 is a data configuration diagram of encoded information for explaining the operation according to an embodiment of the present invention.

FIG. 6 is a data configuration diagram of encoded information for explaining an operation according to an embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a radio wave condition monitoring circuit according to an embodiment of the present invention.

FIG. 8 is an AR for explaining an operation according to an embodiment of the present invention.
It is a Q frame block diagram.

FIG. 9 is a schematic configuration diagram of a radio base station according to an embodiment of the present invention.

[Explanation of symbols]

1 Image input circuit 2 Encoding circuit 3 Communication control circuit 4 wireless IF circuit 5 antennas 6 Image output circuit 7 Decoding circuit 8 Conversion processing control circuit 9 Radio wave condition monitoring circuit MF wireless facsimile machine P radio wave BS wireless base station N public network FF fixed station facsimile machine

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI H04N 1/393 H04B 7/26 109M H04Q 7/38 H04L 13/00 305C (56) Reference JP-A-4-90663 (JP, A) JP-A-2-192262 (JP, A) JP-A-61-242157 (JP, A) JP-A-7-79312 (JP, A) JP-A-4-100360 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) H04N 1/32-1/36 H04N 1/42-1/44 H04N 1/38-1/393 H04B 7/24-7/26 113 H04Q 7/00- 7/04

Claims (5)

(57) [Claims] 1. An image communication apparatus for transmitting and receiving image information via a wireless line, wherein the state of the electric wave of the wireless line is judged by the electric wave state judging unit for judging the state of the electric wave of the wireless line. And an image processing unit that performs reduction conversion processing on the image information when it is determined that the image communication apparatus is an image communication apparatus. 2. In an image communication device for transmitting and receiving image information via a wireless line, a state of a radio wave is judged by a radio wave state judging means for judging a state of a radio wave of the wireless line and the radio wave state is bad by the radio wave state judging means. Image processing means for performing reduction conversion processing on the image information when it is determined, and processing notification means for notifying the recipient by inserting a message to that effect in the image when predetermined processing is performed by the image processing means An image communication device comprising: 3. The reduction conversion processing of image information in the image processing means, when the radio wave condition determination means determines that the radio wave condition is poor, a predetermined line of the image information is changed to a completely white line. The image communication device according to claim 1, wherein the image communication device is replaced with a line. 4. The radio wave condition judging means judges whether the radio wave condition is good or bad based on the detection result of the level detecting means for detecting the reception level of the received radio wave and the detection result of the noise detecting means for detecting the noise figure of the external noise. The image communication device according to claim 1, wherein the determination is made. 5. The radio wave condition judging means judges whether the radio wave condition is good or bad in accordance with the frequency of occurrence of retransmission by a retransmission detecting means for detecting occurrence of error retransmission of information transmitted and received on a wireless line. The image communication device according to claim 1, claim 2, or claim 3.