JP3289933B2 - Image transmission 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 transmitting apparatus for transmitting an original image while sequentially reading the image line by line.

[0002]

2. Description of the Related Art Usually, a facsimile apparatus transmits a document image while reading it. In this case, the facsimile apparatus performs an operation of sequentially reading the original image line by line and storing the obtained image information in the buffer memory, and an operation of sequentially reading the stored image information and compressing and transmitting the data. Running.

The speed at which a certain range of images is read varies depending on the linear density to be read. The speed at which image information is transmitted line by line varies depending on the data transmission speed of the image information, the encoding method for data compression, the transmission control procedure, the minimum I / O speed of the receiving side device, and the like.

The line density for reading image information is set by an operator at the time of transmission. The data transmission rate and the encoding method are determined by the facsimile apparatus by a transmission control procedure. The minimum I / O speed is a time required for the receiving apparatus to record the image information received line by line, and is notified from the receiving side to the transmitting side in a transmission control procedure. Then, the transmitting side transmits the image information of each line at a time interval equal to or longer than the notified minimum I / O speed.

If the speed of transmitting image information is lower than the speed of reading image information, the buffer memory becomes full. In this case, the reading operation of the image is temporarily stopped, and the reading operation is resumed when a certain amount of space is created in the buffer memory.

When the image reading is stopped or restarted, the driving device for transporting the document for sub-scanning is intermittently operated.

[0007]

At the time of the above intermittent operation,
Due to the inertia of the entire driving device and the delay of the rising operation of the motor, the original is pulled back or excessively advanced. For this reason, when the intermittent operation occurs, there is a problem that the image reading line position is shifted and the image quality of the read image is deteriorated.

In order to prevent such image quality deterioration,
It is conceivable to increase the memory capacity so that the buffer memory does not become full. However, in this case, another problem that the cost of the apparatus is increased occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing apparatus capable of solving the above-mentioned problems and reducing the deterioration of the quality of a read image without increasing the apparatus cost.

[0010]

SUMMARY OF THE INVENTION The present invention provides an apparatus for determining a linear density and a data transmission speed of a transmission image of a document image when transmitting an image, when the determined data transmission speed is high. Scans the original image at the determined linear density and sequentially transmits the obtained image information as it is,
When the data transmission speed is low, the original image is read at a linear density higher than the linear density, the obtained image information is converted into the determined linear density image information, and transmitted in sequence. I have.

[0011] Further, at the time of image transmission, in addition to the line density of the transmission image, various devices which determine the encoding method of image information, the transmission control procedure, or the minimum time interval for transmitting image information line by line, respectively: Under various conditions determined,
If the required transmission time for image information is short,
While reading and transmitting as usual, if the required transmission time is long, the original image is read at a linear density higher than the determined linear density, converted to a predetermined linear density, and transmitted.

[0012]

When the determined data transmission rate is low, the required transmission time of the image information becomes long. When the transmission time is long in this manner, the reading speed of the image information becomes faster than the transmission speed, and the sub-scanning is temporarily stopped. In this case, the original image is read at a high linear density and set. Since the image information is converted into image information having a linear density, it takes time to generate image information to be transmitted. Therefore, the reading speed is lower than the transmission speed, and there is no need to temporarily stop the sub-scan. This eliminates the intermittent operation of image reading and improves the image quality of the read image. Further, there is no increase in device cost as in the case of increasing the capacity of the buffer memory.

[0013]

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

FIG. 1 is a block diagram showing a facsimile apparatus according to an embodiment of the present invention. In the figure, a scanner 1 reads a document image and extracts image information line by line. This scanner 1 has
A line sensor 1a for reading a document image line by line, a binarizing circuit 1b for converting a read image signal into digital signal image information, and a sub-scanning control means 1c for sub-scanning the document
And so on. In this embodiment, this scanner 1
Are 8 × 3.85 (lines / mm) and 8 × 7.7 (lines / m)
m) and 8 × 15.4 (lines / mm).

The plotter 2 records and outputs an image. The encoding / decoding section 3 compresses image information to be transmitted by various encoding methods, and decodes received image information to restore the original image information. Buffer memory 4
Is for temporarily storing image information.

The modem 5 transmits and receives image information and various procedure signals for transmission control. It is assumed that the facsimile apparatus according to the present embodiment performs communication according to the transmission control procedure of the CC3 G3 facsimile. The network control device 6
A telephone line is connected, and predetermined line control is performed when making and receiving calls. The operation display unit 7 is used by the operator to perform various operations, and displays an operation state of the apparatus. The system control unit 8 is a microphone computer that controls the above units. The system control unit 8 is provided with line OR processing means 8a for converting image information of adjacent plural lines into image information of one line by OR processing. The system bus 9 is a signal line through which the above-described units exchange various control signals and data with each other.

Next, the image transmission processing of the facsimile apparatus of the present embodiment having the above configuration will be described. When sending images,
As shown in FIG. 2, the operator sets a document to be transmitted on the scanner 1 (process 101), and sets the linear density of the transmitted image by a predetermined operation. This setting is performed by designating one of "ordinary characters", "small characters" and "fine characters" (process 102). In this case, “ordinary character” is 8 × 3.85 (book / mm), and “small character” is 8 × 7.7.
(Books / mm), “fine characters” are 8 × 15.4 (books / m
m) respectively. Next, a transmission destination is set and a transmission operation is started (process 103).

As a result, the facsimile apparatus calls the other party (step 104), and when the other party answers,
A known transmission control procedure is started (process 105).

In this transmission control procedure, function information of the receiving side device is received from the receiving side, which is the destination, by a DIS signal, an NSF signal, or the like. In this function information, ECM
(Error Correction Mode), the presence or absence of the communication function, the maximum value of the data transmission speed, the maximum value of the recording linear density, the minimum I / O speed, the encoding method, and the like are shown.

Further, the data transmission speed for transmitting the image information is determined by the modem trading procedure. In the present embodiment, as shown in FIG. 3, the reading line density of the document image and the method of processing the image information are determined based on the data transmission speed determined here and the set line density.

That is, for example, when the line density of the transmission image is 8
If the data transmission rate is set to 9600 bps or 7200 bps, the reading linear density is determined to be 8 × 3.85 (books / mm) so that normal processing is performed. The data transmission speed is 480.
In the case of 0 bps, the reading linear density is 8 × 7.7 (lines / mm)
Is determined to be ORed. In the OR processing in this case, the image information of two adjacent lines of 8.times.7.7 (lines / mm) is converted into image information of one line by taking ORs of pixels at the same position. Further, when the data transmission speed is 2400 bps, the reading linear density is set to 8 × 15.
It is determined that the OR processing is performed at 4 (lines / mm). In this OR processing, image information of four adjacent lines is converted into image information of one line by taking ORs of pixels at the same position.

On the other hand, the linear density of the transmission image is set to 8 × 7.7 (lines / mm), and the data transmission speed is 9600 bps.
Alternatively, when it is determined to be 7200 bps, the reading linear density is determined to be 8 × 7.7 (lines / mm) so that normal processing is performed. Also, the data transmission speed is 4800 bps or 24
00 bps, the read linear density is 8 × 15.
It is determined that OR processing is performed at 4 (lines / mm).

The linear density of the transmission image is 8 × 15.4.
If (line / mm) is set, the reading linear density is determined to be 8 × 15.4 (line / mm) so as to perform normal processing regardless of the data transmission speed (process 106).

Next, the scanner 1 starts reading the original image at the determined reading linear density. Scanner 1
As shown in FIG. 4, the image information obtained in
Transfer to At the time of this transfer, if it is determined that the OR processing is performed in the above processing, the system control unit 8 executes a predetermined OR processing by the line OR processing means 8a. As a result, the image information of the set linear density is always obtained. The encoding / decoding unit 3 sequentially encodes the image information. The image information is temporarily stored in the buffer memory 4.
On the other hand, the modem 5 sequentially reads out the image information from the buffer memory 4 and transmits it via the network control device 6 (process 10).
7).

During the transmission operation, if the speed at which the image information is stored in the buffer memory 4 continues to be higher than the speed at which the image data is read from the buffer memory 4, the buffer memory 4
Is full. In this case, the reading operation of the scanner 1 is temporarily stopped.

The speed at which image information is read from the buffer memory 4 is high when the data transmission speed is high and low when the data transmission speed is low. In the present embodiment, when the data transmission speed is high and the speed at which image information is read from the buffer memory 4 is high, the original image is read at the set linear density and encoded and transmitted as it is in the conventional manner. I have. Thus, image information can be read quickly and transmitted in a short time.

On the other hand, when the reading speed is low, the original image is read at a line density higher than the set line density, and the image information of one line of the set line density is obtained from the obtained image information of a plurality of lines. Generate information. In this case, since it takes time to generate the image information of one line, the speed of storing the image information in the buffer memory 4 decreases. Therefore, the buffer memory 4 does not become full, and the reading operation of the scanner 1 does not pause.

As described above, in this embodiment, when the data transmission speed is low and the speed of reading image information from the buffer memory 4 is low, the reading line density of the scanner 1 is increased and the image The speed at which information is stored has been reduced. This eliminates the intermittent operation of image reading in the scanner 1 and improves the image quality of the read image.

Next, a second embodiment of the present invention will be described.

In this embodiment, the facsimile apparatus is an MH
(Modified Huffman) method, MR (M
modified Relatable Element
It is assumed that an image is transmitted by an encoding method such as an Address Designate method or an MMR (Modified MR) method.

This encoding method is determined to be one method after the transmitting side confirms the device function of the receiving side notified in the transmission control procedure.

In this embodiment, when the encoding method for transmitting an image is determined, the reading linear density and the image information processing method are determined as shown in FIG. 5 based on the encoding method and the set line density. I do.

That is, in the case of the MMR system, the normal processing is performed by adjusting the read line density to each line density of the set transmission image.

In the case of the MR system, the line density of the transmitted image is 8 ×
At 3.85 (lines / mm), the reading linear density is 8 ×
OR treatment is performed at 7.7 (lines / mm). When the line density of the transmission image is 8 × 7.7 (lines / mm), OR processing is performed with the read line density set to 8 × 15.4 (lines / mm). The transmission image has a linear density of 8 × 15.4 (lines / m).
m), the reading linear density is 8 × 15.4 (lines / m
m) and normal processing.

In the case of the MR system, the line density of the transmission image is 8 ×
At 3.85 (lines / mm), the reading linear density is set to 8 × 1
OR treatment is performed at 5.4 (lines / mm). The linear density of the transmitted image is 8 × 7.7 (lines / mm) and 8 × 15.
When it is 4 (lines / mm), it is the same as the above-mentioned MR method.

Generally, the data compression ratio of image information is MMR
System, MR system, and MH system in that order. When the data compression ratio is high, the data amount of the coded image information to be transmitted decreases. When there is no downshift in the data transmission speed, the transmission speed of the image information is constant. Therefore, when the data compression ratio is high, the data stored in the buffer memory 4 is read out quickly. In this case, in this embodiment, since the image is read at a normal linear density and stored in the buffer memory 4, the document image can be read quickly and transmitted in a short time.

On the other hand, when the data compression ratio is high, it takes time to transmit one line, and the reading speed of the image information in the buffer memory 4 becomes slow. In this case, in this embodiment, since the image is read at a line density higher than the set line density, the speed at which the image information is stored in the buffer memory 4 also decreases. Thus, the buffer memory 4 does not become full.

As described above, in the present embodiment, the read line density is changed by the encoding method at the time of transmitting image information, so that the buffer memory 4 becomes full as in the above-described embodiment. As a result, the intermittent operation of the scanner 1 is eliminated, and the image quality of the read image is improved.

Next, a third embodiment of the present invention will be described.

It is assumed that the facsimile apparatus of the present embodiment has two communication functions of a normal transmission control procedure of the G3 standard and an ECM transmission control procedure. Then, at the time of transmission, the device function notified from the receiving side at the start of communication is checked, and if the receiving side has an ECM communication function, the ECM procedure is executed and the function is provided. If not, it is decided to execute the normal G3 procedure.

In this embodiment, when the transmission control procedure to be executed is determined, the read linear density and the method of processing image information are determined according to the result as shown in FIG.

That is, in the case of the normal G3 procedure, even if the line density of the transmission image to be set is any, the normal processing is performed by adjusting the read line density to each line density. On the other hand, E
In the case of the CM procedure, when the linear density of the transmission image is 8 × 3.85 (lines / mm), the read linear density is set to 8 × 7.7 (lines / m).
m) and OR processing. Also, if the linear density of the transmitted image is 8
At the time of × 7.7 (lines / mm), the reading linear density is 8 × 1
OR treatment is performed at 5.4 (lines / mm). When the linear density of the transmission image is 8 × 15.4 (lines / mm), the read linear density is set to 8 × 15.
Normal processing is performed at 4 (lines / mm).

By the way, when a transmission error occurs during the transmission of image information, the retransmission processing is not executed in the normal G3 procedure, but is executed in the ECM procedure. For this reason,
The time required for transmitting image information is ECM in the normal G3 procedure.
Shorter than.

When the time required for transmitting the image information is short, the data stored in the buffer memory 4 is read out quickly. In this case, in this embodiment, since the image is read at a normal linear density and stored in the buffer memory 4, the document image can be read quickly and transmitted in a short time.

On the other hand, if the required time for transmitting the image information is long, it takes time to transmit one line, and the reading speed of the image information from the buffer memory 4 becomes slow. In this case, in this embodiment, since the image is read at a line density higher than the set line density, the speed at which the image information is stored in the buffer memory 4 also decreases. Thus, the buffer memory 4 does not become full.

As described above, in this embodiment, the read line density is changed by the transmission control procedure for transmitting the image information, so that the buffer memory 4 becomes full as in the previous embodiment. The intermittent operation of the scanner 1 is eliminated, and the image quality of the read image is improved.

Next, a fourth embodiment of the present invention will be described.

In this embodiment, the scanner 1 of the facsimile apparatus converts the original image into 8 × 3.85 (lines / mm) or 8 × 3.85 (lines / mm).
It shall be read at a linear density of × 7.7 (lines / mm).
The I / O speed required for reading one line is 10 ms at any of the above line densities.

This facsimile apparatus checks the minimum I / O speed of the receiving apparatus notified from the receiving apparatus at the start of communication, and determines the minimum time interval for transmitting image information line by line. This is a known operation for the receiving side to receive and record the image information line by line in time.

In this embodiment, the image information of each line is transmitted at intervals longer than the determined minimum time interval. In this case, based on the information on the minimum I / O speed notified from the receiving side,
As shown in FIG. 7, the reading line density and the method of processing the image information are determined.

That is, in the figure, “I /
"O speed" is the value of the minimum I / O speed, and "double speed designation"
Are 8 × 3.85 (lines / mm) and 8 × 7.7 (lines / m)
3 shows the relationship between the processing speed at each linear density of m). When "double speed designation" / "presence" is set, when the processing speed per line is a line density of 8 × 7.7 (lines / mm),
The speed is twice as high as that of 8 × 3.85 (lines / mm), and “double speed designation” / “none” indicates that both speeds are the same.

In this embodiment, when the set line density of the transmission image is 8 × 3.85 (lines / mm),
Both “Yes” and “No” for “Double speed designation”, “I /
When the “O speed” is “10 ms”, the reading linear density is set to 8 × 3.
85 (book / mm) for normal processing. Also, “20
ms ”, the reading linear density is 8 × 8 × 7.7 (lines / m
m), when “40 ms”, the reading linear density is 8 × 15.4
(Book / mm), and OR treatment is performed.

On the other hand, when the line density of the transmission image is 8 × 7.7 (lines / mm), when “double speed designation” is “present”,
When the "I / O speed" is equal to or less than "20 ms", the reading linear density is set to 8 * 7.7 (lines / mm), and the normal processing is performed. Then, when “40 ms”, the reading linear density is set to 8
× 15.4 (lines / mm) and OR treatment.

On the other hand, in the case of "double speed designation" / "none", the reading linear density is set to 8 * 7.7 (lines / mm) only when the "I / O speed" is "10 ms". Normal processing,
If it is higher, the reading linear density is set to 8 × 15.4 (lines / m).
m) and OR processing.

When the line density of the transmitted image is 8 × 3.85 (lines / mm), the value of “I / O speed” is set as the minimum time interval for transmitting the image information of each line. on the other hand,
When the linear density of the transmitted image is 8 × 7.7 (lines / mm),
When “double speed designation” is “none”, the value of “I / O speed” is set as it is, and when “double speed designation” is “present”, “I / O speed” is set.
1/2 value of "O speed" is set.

When the minimum time interval is short, the data stored in the buffer memory 4 is read out quickly. In this case, in this embodiment, since the image is read at a normal linear density and stored in the buffer memory 4, the document image can be read quickly and transmitted quickly.

On the other hand, if the minimum time interval is long, it takes time to transmit data per line, and the reading speed of the image information in the buffer memory 4 is reduced. In this case, in this embodiment, since the image is read at a line density higher than the set line density, the speed at which the image information is stored in the buffer memory 4 also decreases. Thus, the buffer memory 4 does not become full.

As described above, in the present embodiment, the I / O
Since the reading linear density is changed by the O speed, the intermittent operation of the scanner 1 due to the buffer memory 4 being full is eliminated and the image quality of the read image is improved as in the above-described embodiment. .

In the above embodiment, the reading linear density of the original image and the processing method of the image information are determined by the data transmission speed, the encoding method of the image information, the transmission control procedure or the minimum time interval. , But may be changed according to a plurality of conditions.

Although the case of a facsimile apparatus has been described as an example, the present invention is naturally applicable to an image transmitting apparatus that sequentially transmits a transmission image while reading one line at a time.

[0061]

As described above, according to the present invention, when transmitting an image, the data transmission rate, the image information encoding method, the transmission control procedure, or the minimum transmission of each line, together with the linear density of the transmitted image. In various devices that determine the time interval, when the required transmission time of the image information under the determined various conditions is short, while reading and transmitting as usual,
If the required transmission time is long, the original image is read at a linear density higher than the determined linear density and converted to a predetermined linear density and then transmitted. Image quality is improved, and there is no increase in apparatus cost such as increasing the capacity of a buffer memory.

[Brief description of the drawings]

FIG. 1 is a block diagram of a facsimile apparatus according to a first embodiment of the present invention.

FIG. 2 is an operation flowchart of a transmission process of the facsimile machine.

FIG. 3 is an explanatory diagram of a reading line density of a document image and a method of processing image information under various conditions.

FIG. 4 is an operation explanatory diagram showing a flow of image information between units at the time of transmission.

FIG. 5 is an explanatory diagram of a method for processing a reading line density of an original image and image information under various conditions according to the second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a reading line density of an original image and a method of processing image information under various conditions according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of a method for processing a reading line density of an original image and image information under various conditions according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scanner 1a Line sensor 1b Binarization circuit 1c Sub-scanning control means 2 Plotter 3 Encoding / decoding part 4 Buffer memory 5 Modem 6 Network control device 7 Operation display part 8 System control part 8a Line or processing means

Claims (4)

(57) [Claims] 1. A means for determining a line density of a transmission image and a data transmission speed of image information at the time of image transmission, and a means for reading image information one line at a time from a document image and sequentially transmitting the data at the determined data transmission speed. And a means for temporarily suspending the reading operation if necessary when the transmission speed is higher than the transmission speed at which the image information is read. High linear density reading means for reading an original image at a higher linear density than the determined linear density when the density is low, and linear density conversion for converting image information obtained by the reading into image information of the determined linear density And an image transmitting apparatus for sequentially transmitting image information obtained by conversion. 2. A means for determining a line density of a transmission image and an encoding method of image information at the time of image transmission, and data compression by an encoding method determined by reading image information line by line from a document image. In an image transmitting apparatus comprising a means for sequentially transmitting, and a means for temporarily stopping the reading operation as necessary when the speed at which the image information is read becomes faster than the speed at which the image is transmitted, When the data compression ratio is low, high linear density reading means for reading an original image at a linear density higher than the determined linear density, and converting image information obtained by the reading into the determined linear density image information An image transmitting apparatus comprising: a linear density converting unit that performs conversion; and a low compression ratio transmitting unit that sequentially transmits image information obtained by conversion. 3. A means for determining a line density of a transmission image and a transmission control procedure to be executed at the time of image transmission, and a means for reading image information line by line from a document image and transmitting the image information sequentially according to the determined transmission control procedure. Means for temporarily stopping the reading operation if necessary when the transmission speed of the image information is higher than the transmission speed. When retransmission processing is performed when an error occurs, high linear density reading means for reading an original image at a linear density higher than the determined linear density, and image information obtained by the reading are determined based on the determined linear density image. An image transmission apparatus comprising: a linear density conversion unit for converting information into information; and a low speed transmission unit for sequentially transmitting image information obtained by the conversion. 4. A means for determining a line density of a transmission image and a minimum time interval for transmitting image information line by line at the time of image transmission, and a minimum time interval determined by reading image information line by line from a document image. Means for sequentially transmitting at the above intervals;
If the determined minimum time interval is long in an image transmitting apparatus that includes means for temporarily suspending a reading operation when transmission cannot be made in A high linear density reading means for reading a document image at a linear density higher than the determined linear density, and a linear density converting means for converting image information obtained by the reading into image information of the determined linear density ,
An image transmission device comprising: a minimum time increase transmission means for sequentially transmitting image information obtained by conversion.