JPH08172522A - Resolution switching device - Google Patents

Abstract

PURPOSE: To provide a resolution switching device selecting automatically proper resolution depending on an original. CONSTITUTION: A communication equipment using an image processing section 2 to binarize data at a prescribed area of the XY coordinate system and sending the data at a prescribed resolution is provided with a calculation section 4 calculating frequency of incidence of '1' or '0' levels of the binarized data for a prescribed area, and a comparator section 5 comparing the frequency of incidence of '1' or '0' levels calculated by the calculation section 4 with a prescribed threshold level and also with a selection section 6 selecting a resolution of data for the transmission based on the result obtained by the comparator section 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resolution switching device for switching the resolution according to the data when transmitting the data in a communication device such as a facsimile.

[0002]

2. Description of the Related Art In a communication device such as a facsimile, when transmitting data such as a text or an image, a resolution (standard / standard) for transmission in each of a main scanning direction and a sub scanning direction is transmitted.
Fine / EX fine mode) is set. For example, 8 dots / mm or 16 dots / mm in the main scanning direction and 3.851 lines / mm or 7.7 in the sub scanning direction.
Resolutions of 1 line / mm and 15.4 lines / mm are set. To send original data by fax,
The original is read according to this resolution, and the binarized data is transmitted to the other party via a predetermined line.

When transmitting a manuscript in such a communication device, the user himself / herself determines the delicateness of the manuscript in advance,
The resolution is selected accordingly and the device is set. That is, the resolution is set to fine (or EX fine) when the characters and drawings of the original are fine, and the resolution is set to standard when the characters and drawings are rough.

[0004]

However, allowing the user to set the resolution in this way causes a troublesome operation and causes various problems when the resolution is set incorrectly. In other words, since the setting of the resolution is left to the user's judgment, the determination of the delicateness of the characters and figures of the original document may vary from person to person, or the setting error may occur due to an operation error. For example, if the standard is selected when the characters and figures of the original are small, the image on the receiving side becomes unclear because a sufficient transmission resolution cannot be obtained. On the other hand, if you select Fine (or EX Fine) when the characters or drawings on the original are rough, the transmission time will be longer than necessary even though the image on the receiving side is almost the same as the standard, and communication costs will increase. Cause to increase.

[0005]

SUMMARY OF THE INVENTION The present invention is a resolution switching device made to solve such a problem.
That is, according to the present invention, in a communication device that binarizes data in a predetermined area composed of an xy coordinate system and transmits the data at a predetermined resolution, a "1" or a "0" in a predetermined area in the binarized data is displayed. Calculation means for calculating the occurrence frequency,
The comparing means for comparing the occurrence frequency of "1" or "0" calculated by the calculating means with a predetermined threshold value, and the resolution for transmitting data based on the result obtained by the comparing means are selected. And a resolution switching device including selection means.

[0006]

In the present invention, the occurrence frequency of "1" or "0" in the binarized data is calculated by the calculation means, and the occurrence frequency is compared with a predetermined threshold value by the comparison means. , Quantitatively determine the delicacy of the data.
That is, it is determined that the document is finer as the frequency of occurrence of "1" or "0" in the binarized data is higher, and the document is coarser as the frequency is low. Further, the selecting means selects the transmission resolution according to the delicateness of the data determined by the comparing means. That is, according to the present invention, it is possible to determine the delicateness of the data to be transmitted and automatically switch the resolution according to the determination.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the resolution switching device of the present invention will be described below with reference to the drawings. FIG. 1 shows the first embodiment of the present invention.
It is a block diagram explaining an Example. The resolution switching device in the first embodiment is mainly composed of a sensor 1 for reading data such as a document, and an image processing unit 2 for amplification of sensor output, A / D conversion, pseudo gradation processing, binarization processing, and the like.
And a page memory 3 for accumulating binarized data, a calculator 4 for calculating the frequency of occurrence of "1" and "0" in the binarized data, and comparison of the frequency of occurrence with a predetermined threshold value. The configuration includes a comparison unit 5 that performs the above, a selection unit 6 that switches the resolution according to the result of the comparison unit 5, and a communication control unit 7 that transmits data according to the selected resolution.

In order to make the explanation easy to understand, a case where the resolution switching device according to the present embodiment is provided in a communication device composed of a facsimile will be described below as an example.
The sensor 1 reads data such as characters and figures written on a document for facsimile transmission line by line and outputs it as image data to the image processing unit 2. The data read by the sensor 1 is performed at the finest resolution. The image processing unit 2 obtains image data which is a sensor output, and performs various processes on the image data, that is, amplification of the sensor output, A / D conversion, pseudo gradation process, binarization process, etc., and page memory 3 and calculation. The binarized data is output to the unit 4.

The calculation unit 4 is composed of an input unit 41, a determination unit 42 and a counter unit 43. This input section 41
Sequentially obtains the binarized data from the image processing unit 2, and the latest two data (1
Data of two adjacent pixels in the line) are stored and output to the determination unit 42. FIG. 2 is a timing chart of the input unit 41 and shows the states of the data A to I (“0” level, “1” level) at times t = 0 to 9.

For example, when the time t = 2, the latest 2
The state (0, 0) of the data of A and B, which are two
Memorize with. When the time t = 3, the input unit 41 stores the latest two data states of B and C (0, 1). Further, when the time t = 9, the input unit 41 stores the latest two data states of H and I (1, 1). The determination unit 42 determines whether the states of the two data sent from the input unit 41 are equal or different, and when they are different, that is, the states of the two data are (1,0) or (0,1). In this case, the information indicating that there is a change point is sent to the counter unit 43 as if it were a change point of the data.

The counter unit 43 adds the counter for the number of change points by receiving the information indicating that there is a change point from the determination unit 42, and outputs the total number of change points in one line to the comparison unit 5. The comparison unit 5 compares the total number of change points in one line obtained from the counter unit 43 with a predetermined threshold value obtained from the threshold value storage unit 51, and outputs the result to the selection unit 6. The comparison result output from the comparison unit 5 is an instruction signal indicating which resolution is selected when transmitting data.

That is, the type of resolution is Mi (however,
i = 1 to n, and the smaller the number, the finer the resolution. ), The threshold value is Thj (j = 1 to (n-1)
, Th1>Th2>...> Thn−1), where C is the total number of change points in one line, the resolution M1 is C ≧ Th1, the resolution M2 is Th1> C ≧ Th2, and Th
When 2> C ≧ Th3, the resolution M3 is set to ... Thn-2> C ≧
When Thn-1, the resolution Mn-1 is Thn-1> C≥Thn.
In this case, the comparison section 5 outputs an instruction signal for selecting each resolution Mn.

That is, the smaller the number of change points of "1" and "0" in the binarized data in one line, the coarser the original data is considered to be, and the coarser resolution is selected. The larger the number of change points, the finer the original data is. Assuming that there is, select a fine resolution. The selection unit 6 receives the instruction signal for selecting the resolution from the comparison unit 5 and selects the resolution according to the instruction signal. The operation unit 61 plays a role of setting whether to automatically switch the resolution according to the operator's selection or outputting information of the selected resolution to the selection unit 6 when manually selecting the resolution. .

The communication control unit 7 carries out a process of transmitting the binarized data sent from the page memory 33 to a destination via a predetermined communication line (not shown) according to the resolution selected by the selection unit 6. Is going. Since the data read by the sensor 1 at the finest resolution is stored in the page memory 3, when the coarse resolution is selected by the selection unit 6, the communication control unit 7 thins out the data. Try to send.

Here, as an example, the resolution E
The case where three types of X fine / fine / standard can be set will be described. In this case, the number of resolutions (n) that can be set is 3, and the type of resolution is M for EX Fine.
1, fine is M2, standard is M3. In addition, the threshold value Th1 determined in advance by experiments is set to 80
0 and Th2 are set to 400. Under such conditions, the total number C of change points of the binarized data in one line is calculated by the calculation unit 4 as described above, and the comparison by the comparison unit 5 is performed.

When C ≧ 800, C ≧ Th1 is satisfied, so the resolution M1 or EX fine is selected, and 8
When 00> C ≧ 400, Th1> C ≧ Th2, so resolution M2, that is, fine is selected. When 400> C, Th2> C, so resolution M3, that is, standard is selected. In this way, it is possible to read the original for transmission and automatically determine the roughness thereof to set the optimum transmission resolution.

Next, a resolution switching device according to the second embodiment of the present invention will be described. FIG. 3 is a block diagram for explaining the second embodiment of the present invention. This resolution switching device
A CPU 10 for controlling the entire apparatus, a document reading sensor 11, a binarization circuit 12 for binarizing the sensor output, a bus interface 13 for connecting the binarized data to a bus 10a, and a binarized data An image memory 15 for storing, a DMAC (Direct Memory Access Controller) 14 for transferring binary data to the image memory 15, and an encoding circuit 16 for encoding (compressing) image data, A run length statistical circuit 17 for counting the frequency of occurrence of a predetermined run length in the binarized data,
It is composed of a modem 18 which modulates encoded data and sends it out to a line.

In the resolution switching apparatus according to the second embodiment, binarized data is obtained from the image data of the original read by the sensor 1, and the occurrence frequency of a predetermined run length in a predetermined area in the binarized data is determined. Run length statistical circuit 17
Is characterized in that the document is delicately determined according to the count value and the optimum transmission resolution is selected.

The run length in the sub-scanning direction will be described with reference to FIG. FIG. 4 shows the data state of each dot when the main scanning direction is x and the sub scanning direction is y. In the figure, white squares indicate white data, and black squares indicate black data. In the portion indicated by (A) in FIG. 4, three pieces of white data are continuous in the sub-scanning direction, and the white run length “3” is generated. Further, in the portion indicated by (B) in the figure, five black data are continuous in the sub-scanning direction, and the black run length "5" is generated. Further, in the portion indicated by (C) in the drawing, three black data are continuous in the sub-scanning direction, and the black run length "3" is generated.

The run length statistical circuit 17 shown in FIG. 3 counts the frequency of occurrence of a predetermined run length in a predetermined area in the binarized data in this way, and provides information for judging the delicacy of the original. Play a role in gaining. Figure 5
It is an internal block diagram of a run length statistical circuit for performing such run length counting. The run length statistical circuit includes a bus interface circuit 21, a DMAC 22,
A black and white change point detector 23 and a black and white change point detector 24,
A black run length counter 25 and a white run length counter 26,
Frequency counters 27 to 29 for counting the frequencies of the black run lengths "1", "2", and "3" and the white run length "1",
It is composed of frequency counters 30 to 32 for counting the frequencies of "2" and "3", respectively.

In the run length statistical circuit 17 (see FIG. 3) having such a configuration, the occurrence frequency of "1", "2" and "3" of the black run length and the white run length can be counted. Has become. For example, when "white" and "black" data is input to the run length statistical circuit 17 dot by dot along the sub-scanning direction in the binarized data as shown in FIG. 4, the black run length " The frequency of occurrence of 1 "to" 3 "and the frequency of occurrence of white run lengths" 1 "to" 3 "are counted. In the configuration shown in FIG. 5, run lengths of "4" and above are not counted.

For example, "black" is added to the run length statistical circuit 17.
When data is input, the data is serially input to the black run length counter 25, and the black run length is counted. This count is based on the black and white change point detector 23.
Is continued until a signal is given from, and output is performed according to the black run length.

That is, when the black and white change point detector 23 detects a change point and the output thereof is input to the black run length counter 25, the count value at that stage, that is, the frequency corresponding to the value of the black run length. Any of the counters 27 to 29 is counted up. At the same time as this count-up, the black run length counter 25 is reset to prepare for the next black run length count. Similarly, with respect to the white run length, the frequency counters 30 to 32 corresponding to the run length value output from the white run length counter 26 are incremented when the white / black change point detector 24 outputs. It will be.

FIG. 6 is a timing chart of the run length statistical circuit. That is, the run length statistical circuit is 2
Value (= 1) data and white (= 1) data
0) A continuous value of data will be counted. The black run length can be obtained by the black run length counter output when there is a black and white change point detection output, and the white run length can be obtained by the white run length counter output when there is a black and white change point detection output. it can. "1" to "3" obtained in this way
The occurrence frequencies of the black run length and the white run length up to are counted by the frequency counters 27 to 32 for each run length shown in FIG.

In the resolution switching apparatus in the second embodiment, the frequency of occurrence of the black run length and the white run length is first shown in FIG.
For the first line along the sub-scanning direction (x = 0)
The counters other than the frequency counters 27 to 32, that is, the black run length counter 25 and the white run length counter 26 are once reset at the stage of counting.
Then, the value of x is incremented and the same counting is performed, and finally the occurrence frequency of the black run length and the white run length for one page is counted. When the count for one page is completed, the values of the frequency counters 27 to 32 are sent to the CPU 10 via the bus 10a shown in FIG.

The CPU 10 has a run length statistical circuit 17
The delicateness of the original is quantitatively determined according to the occurrence frequency of each of the black run length and the white run length of "1" to "3" obtained from
A process for selecting a transmission resolution adapted to that is performed.

FIG. 7 is a flow chart for explaining an example of resolution switching processing by the CPU. In this example, three resolutions in the sub-scanning direction (3.851 lines / mm,
7.71 lines / mm, 15.4 lines / mm). First, the CPU 10 (see FIG. 3) performs a process of reading the frequency counter of each run length from the run length statistical circuit 17 (see FIG. 3) (step S1). Here, BRL (1) is the frequency of the black run length "1", BR
L (2) is the frequency of the black run length “2”, BRL (3) is the frequency of the black run length “3”, WRL (1) is the frequency of the white run length “1”, and WRL (2) is the white. Frequency of run length "2",
WRL (3) indicates the frequency of the white run length "3".

Next, the CPU 10 (see FIG. 3) causes the BRL
(1) + WRL (1) is compared to see if it is smaller than a predetermined threshold value T1 (step S2). If the determination in step S2 is Yes (BRL (1) + WRL (1) is smaller than the threshold value T1), the process proceeds to the next step S3. On the contrary, the determination in step S2 is No.
If (BRL (1) + WRL (1) is greater than or equal to the threshold value T1), the process proceeds to step S7, and resolution = 15.4.
A process of selecting books / mm is performed.

That is, the black run length "1" and the white run length "1".
That is, the fact that the sum of the above occurs more than a certain threshold value T1 means that there are fine characters and figures in the document, and the finest resolution is selected. Next, if the determination in step S2 is Yes, C
The PU 10 (see FIG. 3) makes the determination in step S3, that is, B.
RL (1) + WRL (1) + BRL (2) + WRL
It is determined whether or not (2) is smaller than the threshold value T2.
If the result of this determination is Yes, the process proceeds to the next step S4, and if the result is No, a process of selecting resolution = 7.71 lines / mm is performed in step S6. That is,
BRL (1) + WRL (1) + BRL (2) + WRL
The fact that (2) is above the threshold value T2 means that
Since medium delicate characters and figures are present in the manuscript, the medium resolution is selected.

If the determination in step S3 is Yes, the determination in step S4, that is, BRL (1)
+ WRL (1) + BRL (2) + WRL (2) + BRL
(3) + WRL (3) is judged whether it is smaller than the threshold value T3. If the result of this judgment is No, the operation proceeds to step S6, where the medium resolution is 7.71 lines / mm.
The process of selecting is performed. On the other hand, if this determination is Yes, the process proceeds to step S5, and the process of selecting the coarsest resolution of 3.851 lines / mm is performed.

That is, BRL (1) + WRL (1) +
BRL (2) + WRL (2) + BRL (3) + WRL
The fact that (3) is smaller than the threshold value T3 indicates that the black-lens length and the white-lens lengths "1" to "3" are not frequently generated. That is, the black len length and the white len length of “4” or more occupy most of the original, which means that the characters and figures in the original are rough. For this reason, if the determination in step S4 is Yes, the coarsest document is selected and the coarsest resolution is selected.

The CPU 10 (see FIG. 3) appropriately selects the resolution in data transmission according to the delicateness of the original by performing the above processing. DM shown in FIG.
The AC 14 reads out a required amount of data from the image memory 15 according to the resolution selected by the CPU 10. For example, if a resolution of 15.4 lines / mm is selected,
When all the data stored in the image memory 15 is read and the resolution of 7.71 lines / mm is selected,
The data stored in the image memory 15 is read every two main scanning lines, and the data of one line is read out to obtain a resolution of 3.8.
When 51 lines / mm is selected, data for one line is read every four lines for main scanning. Then, the data read by the DMAC 14 is used as the encoding circuit 1.
6, the resolution is converted here, and the modulated data is sent to the line via the modem 18.

As described above, in the resolution switching apparatus according to the second embodiment, the frequency of occurrence of the black run length and the white run length of a predetermined length is calculated to determine the delicacy of the original, and the appropriate transmission according to this is calculated. Since the resolution is selected, it is possible to switch the resolution while accurately grasping the delicacy of the original.

In the second embodiment, an example of discriminating the fineness of a document based on the occurrence frequency of the black run length and the white run length has been shown. However, either the black run length or the white run length is generated. The determination may be made based on the frequency. Also, an example in which the run length statistical circuit 17 (see FIG. 3) that counts “1” to “3” as the black and white run lengths is used has been shown. The frequency of occurrence of a long run length may be counted.

Although an example of counting the occurrence frequency of the black run length and the white run length along the sub-scanning direction has been shown, the occurrence frequency of the black run length and the white run length along the main scanning direction is counted. The same applies when the resolution is switched in the main scanning direction. Furthermore, although an example in which the run length statistical circuit 17 is used as dedicated hardware has been shown, the same applies to the case where it is realized by the programmed CPU 10. Further, as the resolution conversion method, simple thinning (a method of reading out one line of data every other number of main scanning lines) is used, but the present invention is not limited to this. For example, a certain type of image processing using a discard line is used. Other methods such as resolution conversion may be used.

Further, in the first and second embodiments,
In both cases, image data (binarized data) is stored in page memory 3
And an example in which the image data is stored in the image memory 15 is shown.
The frequency of occurrence of “black”, that is, “0” and “1” of the data may be calculated. The area for calculating the occurrence frequency is not limited to one line or one page, and the occurrence frequency for each specific area may be calculated. In this case, “0” for each specific area is calculated. , "1"
The delicateness of the document may be determined by using the distribution rate of the occurrence frequency of.

Further, the resolution switching device according to the present invention is not limited to the case where it is provided in a communication device composed of a facsimile, but the same applies when it is applied to communication by various communication devices having variable resolutions such as a personal computer.

[0038]

As described above, the resolution switching device of the present invention has the following effects. That is,
In the present invention, the calculation unit automatically determines the delicacy of the original, and the selection unit selects the resolution based on the determination. Therefore, the operator does not need to switch the resolution and perform the selection operation, and the optimum resolution can be obtained. It becomes possible to set automatically. As a result, the data of the original can be transmitted with sufficient definition, and since it can be transmitted within an appropriate transmission time, the communication cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a first embodiment of the present invention.

FIG. 2 is a timing chart of an input unit.

FIG. 3 is a configuration diagram illustrating a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a run length in a sub operation direction.

FIG. 5 is an internal configuration diagram of a run length statistical circuit.

FIG. 6 is a timing chart of a run length statistical circuit.

FIG. 7 is a flowchart illustrating a resolution switching process.

[Explanation of symbols]

 1 Sensor 2 Image Processing Section 3 Page Memory 4 Calculation Section 5 Comparison Section 6 Selection Section 7 Communication Control Section 10 CPU 17 Run Length Statistical Circuit 41 Input Section 42 Judgment Section 43 Counter Section 51 Threshold Storage Section 61 Operation Section

Claims (3)

[Claims] 1. A communication device for binarizing data in a predetermined area consisting of an xy coordinate system and transmitting the data at a predetermined resolution, in which "1" or "0" in a certain area in the binarized data is set. Calculation means for calculating the occurrence frequency, comparison means for comparing the occurrence frequency of "1" or "0" calculated by the calculation means with a predetermined threshold value, and based on the result obtained by the comparison means A resolution switching device, comprising: a selection unit that selects a resolution when transmitting the data. 2. The resolution switching device according to claim 1, wherein the calculation means calculates the occurrence frequency based on the number of change points of "1" and "0" of the binarized data. 3. The calculation means calculates the occurrence frequency based on a frequency of a predetermined run length in “1” or “0” of the binarized data.
The resolution switching device described.