JPH0823439A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To compress image data efficiently even when correlation of an image is large in any of longitudinal/lateral directions and to correct a tilted image even when the tilted image is received. CONSTITUTION:The facsimile equipment having a memory 4 storing read or received image is provided with a rotation means 6 rotating the image stored in the memory 4. When the image stored in the memory 4 is transferred, the image is rotated to obtain a state of efficient compression or when an image with a tilt is received, the image is rotated to correct the tilt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile machine, and more particularly to a facsimile machine which can effectively compress image information.

[0002]

2. Description of the Related Art A conventional facsimile apparatus, as shown in FIG. 23, controls a unit 1 for controlling the entire apparatus, a communication controller 2 for communicating via a communication network, and an image written on paper. A scanner unit 3 for reading, a memory 4 for storing image data and the like, and a printer 5 for outputting the image data received through the communication control unit 2 on paper are provided.

When transmitting an image, this facsimile machine first reads image data by the scanner section 3,
The data is once stored in the memory 4. Next, the control unit 1 compresses the data and transfers it to the communication control unit 2, and the communication control unit 2 transmits the data to another facsimile machine through the communication network. Since the image data is read and transmitted in parallel and continuously, the read data is transmitted one after another.

The compression of the image data is to transmit the data efficiently, and in many facsimile machines, the data compression is performed by the one-dimensional coding (MH compression). Since this one-dimensional encoding is a method of detecting the continuity of white pixels or black pixels for each line in the horizontal direction and performing compression, data having a stronger correlation in the horizontal direction has higher compression efficiency. That is, the compression efficiency is higher for an image in which white areas are continuous in the horizontal direction or an image with more horizontal lines. On the other hand, the compression efficiency of an image such as continuous vertical lines deteriorates in the one-dimensional encoding.

As another method for compressing image data, there is a method called two-dimensional coding (MR compression). Since this two-dimensional encoding collectively compresses several lines, it is effective to some extent even for an image that uses a lot of vertical lines having a strong vertical correlation. There is also a system called MMR coding in which an image is two-dimensionally coded collectively for all lines. Further, there is also known a method of automatically applying these other encoding methods to data having poor compression efficiency in one-dimensional encoding, as described in JP-A-63-69378. ing.

On the other hand, when the facsimile apparatus receives the image data, the coded data input through the communication control unit 2 is stored in the memory 4, and the control unit 1 expands the compressed data and the printer 1 Output through 5. Since the data reception and the output to the printer are continuously performed in parallel, the data is printed out while being received.

The facsimile device has a function of storing the data received from the communication control unit 2 in the memory 4 as it is and sending it to another facsimile device through the communication control unit 2 again by a user's operation. There is also a device called.

In facsimile communication, an image may be read obliquely depending on the mechanical characteristics of the scanner 3 of the facsimile apparatus and the way of setting the original paper. An image read obliquely in this way is not only difficult to read on the receiving side, and is not optimal in terms of image compression coding. In other words, an image with a lot of horizontal lines that should normally be expected to have the effect of compression in one-dimensional encoding, is not read as a horizontal line when it is read diagonally, and the effect of compression in one-dimensional encoding is reduced. You will not be able to get enough.

In order to deal with such a situation, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Laid-Open No. 306065, a device for correcting the inclination of an image by changing the mechanical portion of the scanner of a facsimile device or a device for detecting the inclination of an original in the scanner portion to correct the inclination of the image is provided. It is considered.

[0010]

However, in the conventional facsimile apparatus, when vertical lines are frequently used in the original,
There is a problem that the compression efficiency of image data is lower than that when the horizontal lines are frequently used.

As described above, by applying the two-dimensional coding (MR compression), it is possible to enhance the compression effect on the image data in which vertical lines are frequently used, but in this case, horizontal lines are often used. It is not as effective as one-dimensional encoding compression for image data. This depends on the fact that the data transmission of the facsimile is performed in units of horizontal lines. That is, the one-dimensional encoding can compress one whole line in the horizontal direction, while the two-dimensional encoding can compress the entire line in accordance with ITU-TS (International Telecommunications Standardization Center: Old C).
CITT) Recommendation T.I. 2 as standard, as shown in 4
This is because only lines and up to 4 lines can be optionally compressed together.

Further, in order to communicate with two-dimensionally encoded data, the facsimile machine of the other party must also be equipped with a two-dimensional encoding device, but at present, all of the commonly used facsimile machines are available. Since the device is not equipped with a two-dimensional encoding device, improvement in compression due to the two-dimensional encoding is hardly expected in practice.

Further, in the facsimile apparatus, there is such an image direction suitable for image data compression, and when the image on the original paper is read in conformity with the image direction, the efficiency of image data compression is improved. However, since this is not generally known, it is not usual for users to set the manuscript paper in mind, and even if they try to do so, the operation is troublesome. is there.

Further, in the conventional facsimile apparatus, as described above, there are some measures for preventing the image from being obliquely read at the time of transmission, but the image is read while being inclined at the transmitting side. If it happens, there is a problem that it cannot be corrected on the receiving side. Therefore, the receiving side prints out an image that is difficult to see diagonally, and the facsimile storage and exchange device sends the received tilted image to another facsimile device as it is.

The present invention solves the above-mentioned conventional problems. Image data can be efficiently compressed and tilted regardless of the vertical or horizontal direction of image correlation. It is an object of the present invention to provide a facsimile device that can correct an image when it is received.

[0016]

Therefore, in the present invention, in a facsimile apparatus having a memory for accumulating the read or received image, a rotating means for rotating the image accumulated in the memory is provided.

Further, the rotating means rotates the image stored in the memory by 90 degrees, compares the image data obtained by compressing the rotated image with the image data obtained by compressing the original image, and determines the compression efficiency. It is configured to transfer the higher image data.

Further, an image range detecting means for detecting the existence range of the image is provided, and the rotating means rotates the image when the detected image does not extend beyond the transmission range of the image even if it is rotated by 90 degrees. are doing.

Further, an inclination detection means for scanning the image stored in the memory at various angles to detect the inclination of the image is provided, and the rotation means rotates the image so as to correct the detected inclination of the image. It is done.

Further, an image range detecting means for detecting the existing range of the image is provided, and the rotating means is used for correcting the inclination of the image within a range in which the detected image does not exceed the transmission range of the image due to the rotation. Is being carried out.

Further, an image range detecting means for detecting the existence range of the image is provided, and the rotating means is caused to rotate the image so that the arrangement is optimum for compressing the image data.

[0022]

Therefore, when transmitting the image stored in the memory, the image is rotated so that it can be compressed efficiently, and when the image read diagonally is received, the image is rotated. It is possible to correct the inclination.

Whether the image read by the scanner is an image using a lot of vertical lines or an image using a lot of horizontal lines, by compressing the original image and the image obtained by rotating the original image by 90 degrees, In either case, the optimum compression efficiency can be obtained. Therefore, by selecting the image data having the higher compression efficiency, it is possible to perform the transmission with the optimum compression efficiency, and it is possible to reduce the transmission time and the transmission cost.

Further, when the received image is tilted, the blank portions between the lines of the image and the ruled lines are tilted along the tilt angle. By detecting the blank portion or ruled line, the angle of inclination of the image can be obtained, and the image can be corrected by rotating the image by the rotating means by the obtained angle.

Further, when the image is rotated, if the image is out of the range of the document (transmittable range), such rotation is not performed. Whether or not the image protrudes due to the rotation can be determined by knowing the existence range of the original image.

Further, when the image read by the scanner is transmitted by electric power, the rotation angle of the image can be controlled to an angle at which the optimum compression efficiency is obtained.

[0027]

【Example】

(First Embodiment) The facsimile apparatus of the first embodiment is shown in FIG.
As shown in FIG. 3, a 90-degree rotation device 6 that rotates the image data by 90 degrees is provided. Other configurations are the same as those of the conventional device (see FIG.
Same as 3).

Two modes are prepared for this facsimile transmission. One is a normal facsimile transmission, and the other is a facsimile transmission that allows rotation of an image.

When the user selects the normal facsimile transmission mode, the 90-degree rotating means 6 is not used,
Image data is transmitted in the same procedure as the conventional transmission procedure.

On the other hand, when the user selects the mode that allows the rotation of the image, the 90-degree rotation device 6 is activated, and the image data read by the scanner unit 3 is changed to the 90-degree rotation device 6.
After being rotated by 90 degrees, compression by one-dimensional coding is performed. For example, as shown in FIG. 3A, when an image with many vertical lines or an image with strong vertical correlation is transmitted, the compression effect by the one-dimensional encoding is low as it is, but 90 ° By rotating the image data,
The state is changed to the state of (b), and as a result, the compression effect by the one-dimensional encoding is improved, and the transmission efficiency of image data is increased.

FIG. 2 is a flow chart showing the processing procedure at this time.

Step 201: If the mode selected by the user is a rotation-allowed mode, Step 202: read the data of the entire image from the scanner 3 and temporarily store it in the memory 4, and Step 203: then the image. The data is rotated by the 90 ° rotation means 6 and stored in another area of the memory 4.

Step 204: The control unit 1 compresses the entire original image data read from the scanner, Step 205: compresses the entire image data after rotation, Step 206: The size of both images after compression. (Data size) are compared, and step 207: The smaller one is transmitted from the communication control unit 2.

The following procedure is used to rotate the image by 90 degrees. With respect to the image data of FIG. 4A, it is assumed that the origin is at the upper left corner of the document sheet, X is rightward, and Y is downwardly coordinated. This image data is converted into certain coordinates (p, q)
When rotated 90 degrees counterclockwise about, the coordinate (X ₀ ,
The coordinates (X ₀ ', Y ₀ ') in FIG. 4B after the movement of Y ₀ ).
Can be obtained as (Y ₀ + p−q, −X ₀ + p + q).

By one-dimensionally encoding the image data processed in this way, the data size to be transmitted can be made small and the time for using the communication network can be reduced. As a result, communication costs can be saved.

(Second Embodiment) As shown in FIG. 5, the facsimile apparatus according to the second embodiment includes an image range detecting device 7 for detecting the image range. The other structure is the same as that of the device of the first embodiment (FIG. 1).

In the facsimile apparatus of the first embodiment, the image may exceed the range of the document (transmittable range) by rotating the image by 90 degrees. In the facsimile apparatus according to the second embodiment, the image range detecting device 7 detects the existing range of the image, and rotates the image only when it does not exceed the transmittable range even when rotated by 90 degrees.

This facsimile machine executes step 203 (image 9) in executing the flowchart of FIG.
Rotation is carried out by the procedure shown in FIG.

Step 601: First, the range of the image is obtained. As shown in FIG. 7, the image range is the number of black pixels in the Y-direction dot row at each X-coordinate and the Y-direction dot row at each Y-coordinate for the image data stored in the memory 4. The number of black pixels is detected. The area where the number of pixels exceeds a certain threshold value (Vx, Vy) from the beginning to the end is defined as the image existence range. In FIG. 7, X1 to X2 and Y1 to Y2 are image existence ranges.

Step 602: Normally for facsimile,
The width of the original, that is, the width W that can be transmitted is determined, and if the image cannot be cut from this width, Y2 to Y
The value minus 1 must not exceed W. If Y2-Y
If 1 ≦ W is not satisfied, the image cannot be rotated by 90 degrees, and therefore the image is not rotated. If Y2-Y1≤W, step 603: The position of the point (X2, Y1) is the point (0,
0 (point) ((X2-Y1) /
2. Rotate the image 90 degrees around (X2 + Y1) / 2).

If the transmittable vertical width (H) is also determined in step 602, Y2-Y1≤W
And if the two expressions of X2-X1≤H are not satisfied,
Do not rotate 90 degrees.

By doing so, it is possible to prevent the image from being cut off due to the rotation of the image.

(Third Embodiment) In a facsimile apparatus of the third embodiment, when an inclined image as shown in FIG. 10A is received, it is corrected as shown in FIG. Can be output from or sent to another fax machine.

As shown in FIG. 8, this apparatus is provided with a minute rotation device 8 for rotating the image data and an inclination detection device 9 for detecting the inclination of the image data. Other configurations are the same as those of the conventional device (FIG. 23).

This facsimile machine performs the image receiving process in the procedure of the flowchart of FIG.

Step 901: The image of the document created by a word processor or the like is displayed on this facsimile apparatus as shown in FIG.
When it is sent with inclination as shown in (a), Step 902: The data received through the communication control unit 2 is once stored in the memory 4, and the control unit 1 expands the compressed data, The image data resulting from the expansion is stored in another area of the memory 4.

Step 903: When the mode is set to permit the correction of the image, Step 904: The inclination detecting device 9 detects the inclination of the image with respect to this image data.

Step 905: When the tilt of the image is detected, Step 906: The minute rotation device 8 rotates the image data by the amount of correcting the tilt, and the image data of the rotated result is stored in the memory 4 until now. Store in a different area than.

Step 907: The image data whose inclination is corrected is output to the printer 5 or is compressed again and sent to another facsimile.

To detect the inclination of the image in step 904,
The following principle is used. In the case of an original written or printed by a word processor or the like, there is a blank portion between lines. Therefore, the image of such an original is
When scanning for each Y coordinate in the X direction (horizontal direction) and checking how many black pixels there are in each scanning, FIG.
As shown in FIG. 5, a part with few black pixels appears periodically corresponding to the blank part between rows. On the other hand, in an image of a document that uses many ruled lines such as a form, on the contrary, black pixel peaks periodically appear. These periodicities can be detected by obtaining the autocorrelation function.

On the other hand, when the image is tilted and the scanning direction does not match the direction of the blank portion or the ruled line, the periodicity becomes weak. Therefore, the inclination of the image can be obtained by gradually changing the scanning angle and detecting the angle at which the periodicity appears remarkably.

In practice, the algorithm shown in the flowchart of FIG. 13 is used. First, as shown in FIG.
From a certain coordinate (X ₀ , Y ₀ ), the angle with respect to the Y axis is θ _−n
To θ _n , the image is scanned in the inclined direction while increasing the inclination at a predetermined step angle, the number of black pixels on each scanning line is counted, and the value is set to the array value A (Y
_k , θ _i ) (repeated portion from step 1303 to step 1305). This operation is performed by (X ₀ ,
Y ₀ ), (X ₀ , Y ₁ ), (X ₀ , Y ₂ ), ... (X ₀ ,
Repeat at each point of (Y _k ), until (X ₀ , Y _m ) (repeating from step 1302 to step 1307).

Step 1308: After completion of scanning, the number of black pixels A obtained by scanning from each Y coordinate for each inclination θi
(Y _k , θ _i ) (where k is 0 to m) is collected as shown in FIG. 14, and step 1309: The autocorrelation is detected for each inclination, and as shown by θj in FIG. When it is possible to find the one in which the remarkable periodicity appears, step 1310: It is judged that this image has the inclination θj.

Step 1311: If there is no autocorrelation, it is judged that the inclination cannot be detected.

To correct the image tilt (step 90)
6) As shown in FIG. 15, the center of the document (transmission range) is taken as the origin, and the origin is rotated counterclockwise by the detected inclination angle θ. At this time, the original coordinates (X
Coordinates (X ₀ ', Y ₀ ') transferred after ₀ , Y ₀ ) are rotated
Can be obtained from the following equation 1.

[Equation 1] By correcting the inclination of the image in this way, it is possible to obtain an image that is easy to read and has no inclination. Moreover, even when the received image data is retransmitted, the transmission data can be compressed to a small size, which reduces communication costs. It is possible to save communication time.

(Fourth Embodiment) The facsimile apparatus of the fourth embodiment is constructed so that the image does not exceed the range of the original paper when the image is slightly rotated.

As shown in FIG. 16, this facsimile device is equipped with an image range detecting device 7 for detecting the existing range of an image. The other structure is the device of the third embodiment (FIG. 8).
There is no change.

This image range detecting device 7 performs the same operation as the image range detecting device in the second embodiment.

This facsimile apparatus can limit the range of scanning angle (± θa in FIG. 12) in the scanning in step 1303 of the flowchart in FIG. By limiting the scanning angle, the tilt detection range, that is, the maximum correction angle can be limited, and the image can be prevented from exceeding the range of the document.

The image receiving process in this facsimile is as shown in the flowchart of FIG. This process is performed by referring to step 1701 in the flowchart shown in FIG.
1702 and 1703 are added.

The added operation will be described.

Step 1701: The existence range of the image is detected. The same method as the image range detection of the second embodiment is used to detect the existing range.

Step 1702: Next, as shown in FIG. 18, the image is translated so that the center of the image becomes the center of the document. In the following explanation, the image after this translation is
A coordinate system in which the origin is at the center of the original, x is rightward, and y is upward is described (FIG. 19). The farthest point (x ₀ , y ₀ ) from the center in the existence range of the image is the point that was (X ₂ , Y ₁ ) at the coordinates before the parallel movement. The point (x ₀ ′, y ₀ ′) when this point is rotationally moved by θ in the counterclockwise direction around the origin as shown in FIG. 19, is given by Expression 1.

Step 1703: This point (x ₀ ',
The maximum rotation angle is calculated so that y ₀ ') does not exceed the range of the document due to the rotational movement.

If the two conditions of the following expression 2 are satisfied, the rotation range becomes free.

R ≦ H / 2, r ≦ W / 2 (2) where r is the distance from the origin to the point (x ₀ , y ₀ ) and is given by the following expression 3.

R = √ (x ₀ ² + y ₀ ² ) (3) When Expression 2 is not satisfied, the maximum rotation angle θa when θ is positive is (x ₀ ′, y ₀₎ as shown in FIG. Since ') is the state where it overlaps the edge of the document, it is calculated as in Equation 4.

Θa = θ ₀ ′ −θ ₀ = sin ⁻¹ (H / 2r) −sin ⁻¹ (y ₀ / r) (4) The maximum rotation angle θa when θ is negative is also given by Equation 5. To be θa = θ ₀ ′ −θ ₀ = cos ⁻¹ (W / 2r) −cos ⁻¹ (x ₀ / r) (5) Of the absolute values of these two θa, the smaller one is the maximum rotation angle. The smaller one is used so that the coordinate (X ₁ , Y ₁ ) before the parallel movement does not exceed the range of the original due to the rotational movement.

Next, the process proceeds to the image inclination detection in step 904. Here, when the image is scanned, the range is ± θa (FIG. 1) based on θa calculated in step 1703.
Limited to 2).

As described above, it is possible to prevent the image from being cut off when the image is rotated in the third embodiment.

In this example, the image is translated in step 1702, but this is for the purpose of simplifying the description, and the range of the rotation angle of the image can be calculated without the translation. The device does not particularly require translation.

(Fifth Embodiment) The facsimile apparatus of the fifth embodiment rotates an image at a plurality of angles as shown in FIG.
It is possible to select the angle with the highest compression efficiency and send the compressed image.

As shown in FIG. 20, this apparatus has a structure excluding the inclination detecting device 9 in the apparatus of the fourth embodiment (FIG. 16).

This facsimile machine operates according to the flowchart shown in FIG.

Step 2201: If the rotation mode is permitted, Step 2203: The entire image is read from the scanner section 3 and stored in the memory 4.

With respect to this image data, by the same operation as in the fourth embodiment, step 2204: confirm the existence range of the image, step 2205: move the image to the center of the document, step 2206: set the maximum rotation angle. calculate.

Next, Steps 2207 to 2210: The image is slightly rotated at a plurality of angles within the range of the maximum rotation angle, and each rotated image is compressed. Step 2211: The image with the highest compression efficiency, that is, the compressed and smallest image is transmitted.

As described above, the facsimile apparatus according to the fifth embodiment can rotate an image to a position most suitable for compression and transmit the image.

[0079]

As is apparent from the above description of the embodiments, the facsimile apparatus of the present invention is provided with means for rotating the image in the memory, so that the image to be transmitted by facsimile is arranged in a highly compressed arrangement. It is possible to reduce the use time of the communication network in the facsimile transmission and save the communication cost.

When an image read diagonally is received, its inclination can be corrected and the image can be printed out in an easy-to-see form or transferred to another facsimile apparatus.

Further, in such image processing, it is possible to avoid a situation where a part of the image is out of the image range.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a facsimile transmission operation of the apparatus,

FIG. 3 is a conceptual diagram showing rotation of an image by the apparatus,

FIG. 4 is a conceptual diagram showing conversion of coordinates by rotation of the device,

FIG. 5 is a block diagram showing a configuration of a facsimile apparatus according to a second embodiment of the present invention,

FIG. 6 is a flowchart showing an image rotating operation by the apparatus.

FIG. 7 is a conceptual diagram of an image area detection method by the apparatus,

FIG. 8 is a block diagram showing a configuration of a facsimile apparatus according to a third embodiment of the present invention,

FIG. 9 is a flowchart showing a facsimile receiving operation by the apparatus,

FIG. 10 is a conceptual diagram showing a slight rotation of an image in the apparatus.

FIG. 11 is a conceptual diagram showing the principle of detecting the inclination of an image in the same device;

FIG. 12 is a conceptual diagram showing an image scanning direction in image inclination detection in the same apparatus;

FIG. 13 is a flowchart showing an image tilt detection operation in the apparatus,

FIG. 14 is a conceptual diagram showing determination of image tilt in the same device;

FIG. 15 is a conceptual diagram showing coordinate conversion by minute rotation of an image in the apparatus.

FIG. 16 is a block diagram showing the configuration of a facsimile apparatus according to a fourth embodiment of the present invention,

FIG. 17 is a flowchart showing a facsimile receiving operation in the same apparatus,

FIG. 18 is a conceptual diagram showing parallel movement of images in the apparatus.

FIG. 19 is a conceptual diagram showing coordinate conversion by minute rotation of an image in the same device;

FIG. 20 is a block diagram showing the configuration of a facsimile apparatus according to a fifth embodiment of the present invention,

FIG. 21 is a conceptual diagram showing rotation of an image in the apparatus.

FIG. 22 is a flow chart showing a facsimile transmission operation of the apparatus,

FIG. 23 is a block diagram showing the configuration of a conventional facsimile apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 control part 2 communication control part 3 scanner part 4 memory 5 printer 6 90 degree rotation device 7 image range detection device 8 micro rotation device 9 tilt detection device

Claims (6)

[Claims] 1. A facsimile apparatus provided with a memory for accumulating read or received images, comprising a rotating means for rotating the images accumulated in the memory. 2. The rotating means rotates the image stored in the memory by 90 degrees, compares the compressed image data of the rotated image with the compressed image data of the original image, and compresses the compressed image data. The facsimile apparatus according to claim 1, wherein the image data of the higher efficiency is transferred. 3. An image range detecting means for detecting an existing range of the image is provided, and the rotating means rotates the image when the detected image is rotated by 90 degrees but is not outside the transmission range of the image. The facsimile apparatus according to claim 2, which is characterized in that. 4. An inclination detecting unit for scanning the image stored in the memory at various angles to detect the inclination of the image is provided, and the rotating unit corrects the detected inclination of the image. The image is rotated, according to claim 1.
Facsimile apparatus described in 1. 5. An image range detecting means for detecting an existing range of the image is provided, and the rotating means rotates the image within a range in which the detected image does not exceed the transmission range of the image by rotation. The facsimile apparatus according to claim 4. 6. An image range detecting means for detecting an existing range of an image is provided, and the rotating means rotates the image to an arrangement most suitable for compression of image data.
Facsimile apparatus described in 1.