JP2779553B2 - Image reading apparatus and facsimile apparatus using this image reading apparatus - 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 reading apparatus having a function of sequentially scanning and reading a printed image or the like in a fixed direction, encoding read image data and compressing the data. The present invention further relates to a facsimile apparatus having such an image reading device.

[0002]

2. Description of the Related Art In recent years, facsimile apparatuses have played an extremely important role in the field of data communication. A facsimile converts an image printed on paper or a handwritten image into a CCD (Charge-Cou).
The data is read by a scanner including a pleated device (image sensor) and converted into a digital signal. This digital signal is a MH (Modified Huffma)
n), MR (Modified READ), MMR
It is converted into a compressed digital signal by an encoding system called (Modified MR) or the like.
The compressed digital signal is converted to an analog signal and sent out to a telephone line.

FIG. 25 shows the principle of reading an original in a facsimile apparatus according to the recommendation of CCITT. Referring to FIG. 25, for example, document 10 of ISOA4 size
Are read by a CCD sensor or the like along the main scanning direction. One main scanning row is divided into 1728 pixels, and is converted into a digital signal according to the luminance. The main scan is
This is repeated in the sub-scanning direction orthogonal to the main scanning direction. When the scanning in the sub-scanning direction is completed, the entire document 10 is converted into a digital signal.

An image converted into a digital signal is compressed in accordance with the above-mentioned MH, MR, MMR, etc. The compressed signal is sent out to the line via the modem and transmitted to the other party's facsimile machine.

[0005] The receiving side performs processing on the side opposite to the transmitting side. That is, the receiving facsimile machine converts the received analog signal into a digital signal. The converted digital signal is converted into a digital signal before compression by an expansion process opposite to compression. The original image is obtained by printing the obtained digital signal in the same procedure as when it was read.

[0006] The compression / expansion of a document is performed for the purpose of reducing the amount of data to be transmitted, thereby increasing line utilization efficiency and reducing communication time.

FIGS. 27 and 28 show an MH coding system as an example. The MH code is a one-dimensional run-length coding method. In this method, one line of data consists of a sequence of variable length codes. Each symbol represents a white or black run length. A white run length is called a white run, and a black run length is called a black run. White runs and black runs occur alternately. To ensure that the receiver can motivate the signal, all lines start with a white run sign, and if the actual scan line starts with a black run, the sign indicating a zero-length white run is first Sent. The MH code includes two types of codes, a terminating code and a make-up code.

FIG. 27 shows a terminating code. The terminating code represents a run length from 0 to 63 pixels. To increase the compression efficiency, short codes are assigned to run lengths that often appear in image information.

FIG. 28 shows a makeup code. The make-up code, in combination with the terminating code, is for representing a run length of 64 to 1728 pixels. A run length from 64 to 1728 pixels is initially encoded with a make-up code representing a run length equal to or shorter than the run length. This is followed by a terminating code representing the difference between the actual run length and the run length represented by the make-up code.

The receiver compares the received data with a previously prepared decoding table, thereby obtaining
Data before compression can be obtained.

As described above, by compressing the transmission data using the codes, the image transmission by the facsimile apparatus can be performed efficiently and in a short time.

However, the facsimile machine has the following problems. As shown in FIG.
0 is correctly supplied to the device, and the main scanning direction and the character string 12
If the direction of extension is the same, compression by encoding is performed efficiently.

However, as shown in FIG.
0 is supplied to the apparatus in an inclined state, and the main scanning direction is
, The compression efficiency is reduced. This is for the following reasons.

As described above, the code system assigns short codes to run-lengths that frequently appear in image information, and relatively long codes to run-lengths that appear only infrequently. Therefore, when the direction of the main scanning line 14 read in one main scan does not match the direction of the character string 12 as shown in FIG. 26, the appearance frequency of the run length becomes irregular, and the efficiency of data compression is increased. Gets worse.

Further, consider a case where character strings are arranged at an interval d0 as shown in FIG. If the original 10 is supplied to the facsimile machine in the correct direction,
The main scanning lines existing during the interval d0 all include only white runs. Therefore, an image of this portion can be encoded with very high efficiency using the above-described makeup code. On the other hand, as shown in FIG. 26, when the document 10 is fed to the facsimile apparatus in an inclined state, the main scanning line consisting of only white runs is limited to the interval d1. As is clear from the figure, the interval d1 is much shorter than the interval d0.
Therefore, the compression efficiency in the case shown in FIG. 26 is considerably lower than that in the case shown in FIG.

To solve such a problem, for example, JP-A-55-154871 and JP-A-62-20
No. 6962, JP-A-63-88963, etc.
A facsimile apparatus and the like having a function of detecting the inclination before encoding and correcting the inclination has been proposed.

Japanese Patent Laying-Open No. 55-154871 proposes a document reading method using a sheet with a special mark as a document in a facsimile machine. By detecting this mark when reading a document, the inclination of the document can be known. Data is subjected to coordinate transformation so as to cancel this inclination. Thereby, the coding efficiency can be improved.

Japanese Patent Laying-Open No. 62-206962 proposes using a sensor provided in a document reading section of a facsimile apparatus and detecting a passing time of a leading edge of a supplied document. Two points on the front edge of the document supplied at a predetermined speed
The spatial relationship between the two points can be known by detecting the time difference of passing through the front of the predetermined sensor. The size of the supplied original can also be known at the same time. From these information, the inclination of the document can be known. By performing coordinate transformation on the data so as to cancel the known inclination, the data compression efficiency can be improved.

Japanese Patent Application Laid-Open No. 63-88963 uses a method of detecting the reading time of one end of a document along the sub-scanning direction based on a change in signal level at the time of reading the document. Propose that. At the time of main scanning, writing of data of the main scanning line to the image memory based on the time when the edge of the sheet is detected is started. By using this method, one end of the document is stored in the image memory so as to be always parallel to the end of the image memory. The image itself is also the one in which the inclination of the document is removed, and the compression efficiency is improved.

[0020]

However, the following problems still remain with the above-mentioned conventional technology. For example, consider a language that allows both vertical and horizontal writing of characters, such as Japanese. In such a language, as shown in FIG. 29, what is written vertically on A4 size paper may be supplied to a document reading device of a facsimile machine along the vertical direction of the paper. In such a case, even if the inclination of the document itself is detected and corrected, the compression efficiency cannot be improved in principle.

[0021] Even for a horizontally written document, the same problem occurs when a document is supplied to the reading device in a direction coinciding with the direction in which the character string extends.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image reading apparatus and a facsimile apparatus in which the efficiency of data compression by encoding is higher irrespective of the insertion direction of a document.

[0023]

According to a first aspect of the present invention, there is provided an image reading apparatus which scans an image in a predetermined direction, reads the image, and encodes the read image data. An arrangement direction detecting means for extracting a part of a character string in which a plurality of characters are arranged in a predetermined direction and detecting an arrangement direction of the character string; and a first and a second direction in which the detected arrangement direction is predetermined. Direction determining means for determining which is closer to the image, correcting means for correcting the inclination of the image in the direction closer to the first or second based on the direction determining means, and correction by the correcting means. Encoding means for encoding the image data in the direction determined by the direction determining means.

An image reading apparatus according to a second aspect of the present invention is an image reading apparatus which scans an image in a predetermined direction, reads the image, and encodes the read image data. An array direction detecting means for detecting a portion of the character string arranged in the array, and detecting an array direction of the character string; and a detected first or second direction in which the detected array direction is orthogonal to each other. Direction determining means for determining whether the direction is closer to
Correction means for rotating the read image data of one image by 90 degrees when the determination means determines that the image data is close to the second direction; In step (1), the corrected image data is encoded in the first direction, and if the determination unit determines that the image data is close to the first direction, the image data that has not been corrected by the correction unit and is read is encoded in the first direction. Encoding means.

According to a third aspect of the present invention, a facsimile apparatus reads an image on a document by dividing the image into a plurality of pixels arranged two-dimensionally, and thereby adjusts the luminance of each pixel for each pixel. A pixel signal generating means for generating the pixel signal shown, and a pixel signal storing means each including a plurality of storage cells for storing the pixel signal logically associated with one of the pixels. The plurality of storage cells are logically and two-dimensionally arranged in a predetermined first direction and a second direction intersecting the first direction, corresponding to the arrangement of the plurality of pixels. . The facsimile apparatus according to the present invention further comprises:
Based on the pixel signals stored in the pixel signal storage means, the character array direction indicating the array direction in the array of the plurality of storage cells of the character string included in the image on the document represented by the stored pixel signals is A character arrangement direction detecting means for detecting the character arrangement direction;
Character arrangement direction determining means for determining which of the directions is closer, and in response to the output of the character arrangement direction determining means, the character arrangement direction is closer to the second direction than to the first direction. In this case, the image on the document represented by the stored pixel signal is determined in advance so that the character arrangement direction is closer to the first direction. Image rotation means for rotating by an angle, and signal compression means for reading out the stored pixel signals rotated by the image rotation means from the pixel signal storage means in a first direction and compressing them by a compression code And the pixel signal compressed by the signal compression means,
Transmission means for transmitting to another station via a communication line.

[0026]

According to the image reading apparatus of the present invention, the arrangement direction of the character string is detected by the arrangement direction detecting means from the arrangement of the read image data. Then, it is determined whether the arrangement direction is closer to the first or second direction, the image is corrected in the direction determined to be closer, and the image is encoded along that direction. Therefore, encoding of the image is performed in a direction that matches the arrangement direction of the character strings of the image.

According to the second aspect of the invention, when it is determined that the arrangement direction of the character strings of the image to be read is a direction close to the second direction, the arrangement of the read image data is 90. Degree rotation is corrected. On the other hand, when it is determined that the direction is close to the first direction, encoding is performed in the same direction. Therefore, the arrangement direction of the character strings is always the same as that when reading is performed under the direction that matches the first direction, and encoding is performed according to the first direction.

In the facsimile apparatus according to the third aspect of the present invention, the read image on the document is converted into a pixel signal and stored in an array of storage cells. The direction in which the character string of the original extends in the arrangement of the memory cells is detected, and it is determined whether the character arrangement direction is closer to the first or second direction of the arrangement of the memory cells. When it is determined that the character arrangement direction is closer to the second direction, the image rotating means rotates the image by a predetermined angle so that the character arrangement direction is closer to the first direction. The signal compression unit reads out and encodes the pixel signal from the array of the storage cells along the first direction. Since blank lines between character strings also extend along the same direction as the character arrangement direction, by rotating the image as described above,
The average length of the white run and black run along the first direction is longer than when the image is not rotated, and the number of white runs and black runs is reduced.

[0029]

FIG. 1 is a block diagram showing a schematic configuration of an image reading apparatus on which the present invention is based. Scanner 1
Is a device that sequentially scans a reading target image such as a print image in a certain direction and reads the image. The binarizing unit 2 is a circuit unit that performs a binarizing process on image data read by the scanner 1. . The binarized image data is temporarily stored in the image memory 3.

The inclination detecting section 4 detects a portion corresponding to a character string in the image from the image data of one image stored in the image memory 3, and further detects the inclination of the character string (the character string with respect to the scanning direction). (A skew in the arrangement direction, hereinafter referred to as skew).

The tilt correction 5 corrects (rotates) the binarized image data array in the image memory 3 by the amount of skew detected by the tilt detection unit, and matches the character string array direction with the scanning direction. This is a circuit section for making the arrangement equal to the arrangement of image data when reading is performed in the state where the reading is performed. The corrected image data is temporarily stored in the image memory 3.

The encoding section 6 is a circuit section for performing the above-described encoding processing such as MH, MR, and MMR on the corrected image data. The encoded image data is temporarily stored in the image memory 3. Or transmitted to another facsimile via a transmission mechanism (not shown).

The control section 7 is a circuit section for controlling the entire image reading apparatus, such as the scanner 1, the binarizing section 2, the image memory 3, the tilt detecting section 4, the tilt correcting section 5, and the encoding section 6 described above. .

FIG. 2 is a flowchart showing a schematic operation of the image reading apparatus. The operation when the image reading device reads an image including a character string is as follows.
First, a scanner 1 sequentially scans a print image to be read in a fixed direction and reads image data for one image. A binarization unit 2 performs a binarization process on the read image data. Is applied. The image memory 3 stores the binarized image data.

The tilt detecting section 4 extracts a data portion corresponding to a character display area from the image data of one image stored in the image memory 3 (step n1), and then extracts data corresponding to a character string from the data portion. Extract the part (step n
2) Further, the inclination angle of the character string with respect to the image scanning direction by the scanner 1, that is, the skew of the character string is detected from the data part of the character string (step n3).

The inclination correction unit 5 is configured to store 1 in the image memory 3.
The rotation of the array of the accumulated image data for the image is corrected by the skew detected by the tilt detection unit 4 (step n4). As a result, the arrangement of the stored image data in the image memory 3 is stored again in the same arrangement state as the image data obtained when reading is performed in a state where the arrangement direction of the character string matches the scanning direction. The encoding unit 6 applies, for example, MH, MR, and M to the corrected image data.
Encoding processing such as MR is performed. (Step n5).

The coded image data is transmitted to another facsimile via a transmission mechanism (not shown) as it is, or is temporarily stored in the image memory 3. By correcting the inclination in this way, the compression efficiency at the time of encoding is improved.

FIG. 4 is a block diagram showing a schematic configuration of an image reading apparatus according to an embodiment of the present invention. The scanner 1, the binarizing unit 2, and the image memory 3 shown in FIG. 4 are the same as those shown in FIG. Therefore, detailed description thereof will not be repeated here.

The vertical / horizontal detecting section 104 detects a portion corresponding to a character area in the image from the image data of one image stored in the image memory 3, and furthermore, the character arrangement direction of the character area is changed to horizontal. This is a circuit unit for determining and detecting whether the array direction (array direction coincident with the scan direction) or the vertical array direction (array direction orthogonal to the scan direction).

The rotation processing unit 105 includes a vertical / horizontal detection unit 104
Detects the vertical arrangement direction, corrects the rotation of the binarized image data array in the image memory 3 by 90 degrees, sets the character arrangement direction to the horizontal direction, and performs reading. This is a circuit section for making it equal to the array of image data. The corrected image data is temporarily stored in the image memory 3.

When the vertical / horizontal detecting section 104 detects the vertical arrangement direction, the encoding section 106 applies the vertical / horizontal detecting section 1 to the image data whose rotation has been corrected by the rotation processing section 105.
A circuit unit 04 performs an encoding process on the image data that has been subjected to the binarization process (not subjected to the rotation correction process) when the horizontal arrangement direction is detected. The encoded image data is temporarily stored in the image memory 3 or transmitted to another facsimile or the like via a transmission mechanism (not shown). The control unit 107 is a circuit unit for controlling the entire image reading apparatus, such as the scanner 1, the binarizing unit 2, the image memory 3, the vertical / horizontal detecting unit 104, the rotation processing unit 105, and the encoding unit 106. is there.

The operation when the image reading apparatus reads a document in which characters are written horizontally or a document in which characters are written vertically as an image will be described below. Below, even for horizontal writing,
In the case of vertical writing, a character row or column is called a “character string”.

Here, for simplicity of explanation, a horizontally written document is read with its character string direction set to match the scanning direction, and a vertically written document is read with its character string direction set in the scanning direction. It is assumed that reading is performed while being set so as to be orthogonal to.

First, the scanner 1 sequentially scans a horizontal writing document, a vertical writing document, or the like to be read in a predetermined direction to read image data of one image. Binarization section 2
Performs a binarization process on the read image data. The image memory 3 stores the binarized image data.

The vertical / horizontal detecting section 104 extracts a data portion corresponding to a character area from the image data of one image stored in the image memory 3 (step n11), and from there, a data portion corresponding to a character string is extracted. (Step n1)
2) Further, from the data portion of the character string, it is determined whether the arrangement direction of the character string matches or orthogonal to the image scanning direction by the scanner 1, that is, whether the document is a horizontal writing document or a vertical writing document, and the result is detected ( Step n13).

When the vertical / horizontal detection unit 104 detects a horizontally written document, that is, when it is determined that the character arrangement direction is the horizontal arrangement direction that matches the scanning direction, the encoding unit 106
Performs an encoding process on the image data that has been read and has not been corrected (step n14).

When the vertical / horizontal detection unit 104 detects a vertically written document, that is, when it is determined that the character arrangement direction is a vertical arrangement direction orthogonal to the scanning direction, the rotation processing unit 105 determines whether the The rotation of the array of the accumulated image data for the image is corrected by 90 degrees (step n15). As a result, the arrangement of the stored image data in the image memory 3 is stored again in the same arrangement state as the image data obtained when reading is performed in a state where the arrangement direction of the characters, that is, the arrangement direction of the characters coincides with the scanning direction. become.

The encoding section 106 performs encoding processing such as MH, MR, MMR, etc. on the rotation-corrected image data (step n14).

The encoded image data is transmitted to another facsimile via a transmission mechanism (not shown) as it is, or is temporarily stored in the image memory 3.

In this manner, when a document is read in a state where the character arrangement direction is a vertical arrangement direction orthogonal to the scanning direction, the data compression efficiency is reduced in encoding the read image data. It will increase significantly.

When the above-described image reading apparatus is used for facsimile, the sub data for recognizing whether the encoded image data is a horizontal writing document or a vertical writing document is converted into the encoded sub data. It can be added to image data and transmitted. When decoding the image data, the facsimile receiving the image data may refer to the sub-data and perform 90-degree reverse rotation correction as needed to reproduce the image.

Further, even when the image reading apparatus is an image file apparatus that does not transmit image data, the determination result of the vertical / horizontal detecting unit 104 can be stored together with the encoded image data. When decoding the image data, if the image data is identified as image data of a vertically written document, the image can be reproduced by performing 90-degree reverse rotation correction as necessary.

FIG. 6 is a block diagram showing a schematic configuration of an image reading apparatus according to another embodiment of the present invention.

The image reading apparatus of this embodiment not only determines whether the character arrangement direction is the horizontal arrangement direction or the vertical arrangement direction, but also determines whether the arrangement direction of the character in the horizontal arrangement direction or the vertical arrangement direction is relative to the scanning direction. This embodiment is different from the previous embodiment in that the inclination angle is detected to have only the inclination angle, and correction for the inclination angle is performed prior to encoding of the read image data. In FIG. 6, an inclination angle detection unit 108 is a circuit unit for detecting an inclination angle with respect to the scanning direction in the arrangement direction of the character from the read image data.

The rotation processing unit 115 is different from the rotation processing unit 105 (FIG. 4) of the previous embodiment in that not only the case where the characters are arranged in the vertical direction but also the case where the characters are This is a circuit unit having a function of rotating and correcting the arrangement of image data for an image by the above-described tilt angle.

Other circuit sections, ie, scanner 1, binarizing section 2, image memory 3, vertical / horizontal detecting section 104, encoding section 1
06 and the control unit 107 are the same as those in the previous embodiment shown in FIG. Therefore, a detailed description of them will not be repeated here.

FIG. 7 is a flowchart showing a document reading operation by the image reading apparatus of this embodiment. FIG.
FIG. 4 is a diagram for explaining the relationship between the arrangement direction of the document characters and the scanning direction in the reading operation.

The image reading apparatus of this embodiment operates as follows during reading. The scanner 1 sequentially scans a horizontal writing document, a vertical writing document, or the like to be read in a fixed direction and reads one image data. The binarization unit 2 performs a binarization process on the read image data. The image memory 3 stores the binarized image data.

The vertical / horizontal detecting unit 104 extracts a data portion corresponding to a character area from the image data of one image stored in the image memory 3 (step n21). Next, the vertical / horizontal detecting unit 104 extracts a data portion corresponding to the character string from the data, and from the data portion of the character string, the character arrangement direction substantially matches the image scanning direction by the scanner 1 or substantially orthogonally. Is determined, that is, whether the document is written horizontally or vertically, and the result is detected (step n2).
2).

Whether the vertical / horizontal detection unit 104 detects a horizontally written document or a vertically written document, the inclination detection unit 108
Detects the inclination angle of the arrangement direction with respect to the scanning direction (step n23).

As shown in FIG. 8A, when the document to be read is a horizontally written document A1 including a character line r and the arrangement direction of the character line r has a slight inclination (angle α) in the scanning direction S, That is, when the arrangement direction of the characters is the horizontal arrangement direction, the angle α detected by the inclination angle detection unit 108 is a value of −45 degrees or more and less than 45 degrees. The document to be read is shown in FIG.
As shown in (2), a vertically written document A including a character string c
2, when the arrangement direction of the character string c has a slight inclination (angle β) from the direction orthogonal to the scanning direction S, that is, when the arrangement direction of the characters is the vertical arrangement direction, the inclination angle detection unit 108 detects Is a value of 45 degrees or more and less than 135 degrees.

The rotation processing unit 115 converts the array of the stored image data for one image in the image memory 3 into the tilt angle detection unit 1
The rotation is corrected by the inclination angles α and β detected at step 08 (step n24). As a result, the arrangement of the stored image data in the image memory is stored again in the same arrangement state as the image data obtained when reading is performed in a state where the arrangement direction of the characters matches the scanning direction.

The encoding section 106 performs an encoding process on the image data that has been subjected to the correction process. The encoded image data is transmitted to another facsimile via a transmission mechanism (not shown) as it is, or is temporarily stored in the image memory 3.

As described above, not only the image data in the case where the character arrangement direction is the vertical arrangement direction is not only rotationally corrected so as to have the same arrangement as the reading in the horizontal arrangement direction, but also in the case of the horizontal arrangement direction. Also in the case of the direction, encoding is performed after the rotation of the array of the accumulated image data is corrected by the tilt angle with respect to the scanning direction. Therefore, the data compression efficiency does not decrease due to the overlap where the scanning line intersects the character string.

In this embodiment, as in the apparatus shown in FIG. 4, sub-data for identifying whether the encoded image data is a horizontal writing document or a vertical writing document is added to the image data. I can put it. This makes it possible to correct the image data by 90 ° reverse rotation as necessary during reproduction.

FIG. 9 is a circuit block diagram of a facsimile apparatus according to still another embodiment of the present invention. Referring to FIG. 9, the facsimile apparatus includes a control circuit 16 for controlling the entire apparatus, an operation panel 18 connected to the control circuit 16, and a document to be transmitted under the control of the control circuit 16. A document feed mechanism 24 for feeding for reading, a fluorescent lamp 22 for illuminating the document conveyed by the document feed mechanism 24 for reading, and a control circuit 16 for controlling the lighting of the fluorescent lamp 22 And a reading mechanism 28 for receiving the light beam emitted from the fluorescent lamp 22 and reflected by the original and reading the original by photoelectric conversion, and connected to the control circuit 16 for controlling the received original. And a facsimile apparatus and a telephone line as an interface. LIU to (Line Interf
ace Unit) 32 and a modem 30 for mutually converting an analog signal transmitted through a line and a digital signal handled in the control circuit 16.

The control circuit 16 controls a sensor provided in each section, and monitors a key input by scanning a key on the operation panel 18 and a sensor circuit 64 for processing a signal from the sensor. Panel 18
LED (Light Emitting Diode)
e) a panel controller 66 for controlling lighting, and a mechanics / control for controlling a motor for feeding the original and the recording paper 44, and controlling a print head and a printing pressure of the printing mechanism 26. A recording control circuit 68;
The analog pixel signal obtained by the reading mechanism 28 is
Read processing for controlling to a constant level by C (Auto Gain Control) processing, correcting optical distortion caused by an optical system included in the reading mechanism 28, and signal distortion due to variation in sensitivity of the CCD image sensor. A circuit 70 and a transmission control circuit 72 for controlling data transmission processing by the modem 30 are included.

This facsimile apparatus is further connected to a sensor circuit 64, a panel controller 66, a mechanics / recording control circuit 68, a transmission control circuit 72, and a modem 30. Microcomputer (abbreviated as "microcomputer") 62 for controlling the decoding / decoding process and the operation in the self-diagnosis mode, and the read processing circuit 7
A page memory 76 for storing a digital signal of a read image to be output 0, and a digital image signal stored by the page memory 76 and corrected by the microcomputer 62, which is a characteristic feature of the present invention. Page memories 78, 80, microcomputer 62, mechanics / recording control circuit 68, read processing circuit 70, and page memories 76, 7
8 and 80, and controlled by the microcomputer 62 to control writing of image signals to the page memories 76, 78, 80, reading of image signals therefrom, and encoding / decoding processing. And a memory control circuit 74.

The original feed mechanism 24 includes a feed roller 34 for supplying originals one by one for reading and a rubber plate 38 for separating originals, and a transport roller 36 for driving originals by driving a pulse motor (not shown).
And a document sensor 40 provided between the feeding roller 34 and the rubber plate 38 with a plane on which the document is conveyed interposed therebetween to detect that the document has been set and to provide a signal to that effect to the sensor circuit 64. Between the transport rollers 36 and immediately before the position where the document is irradiated by the fluorescent lamp 22, for detecting both ends of the leading edge of the supplied document and providing a signal to that effect to the sensor circuit 64. And a document end sensor.

The printing mechanism 26 is connected to an out-of-paper sensor 48 for detecting that the recording paper 44 is out of paper, and a mechanics / recording control circuit 68, and prints the recording paper 44 in accordance with a signal given from the mechanics / recording control circuit 68. A thermal head 50 for forming an image on the recording paper 44 by scanning, a roller 52 for holding the recording paper 44 between the thermal head 50 and the roller 52,
And a pulse motor 46 for pulling out the recording paper 44 by rotating the recording paper 44.

The reading mechanism 28 is provided on a mirror 56 for reflecting the light emitted from the fluorescent lamp 22 and reflected on the surface of the original document and guiding it to a predetermined optical path, and on the optical path of the light reflected by the mirror 56. A lens 58 for condensing light rays from the original to form an image of the original, and an image of the original formed by the lens 58 for converting the image of the original into an electric signal by photoelectric conversion and providing the electric signal to the reading processing circuit 70 And a motor 54 for moving the lens 58 and the CCD 60 to predetermined positions according to the magnification.

Referring to FIG. 10, a document end sensor 42 shown in FIG. 9 includes a sensor 42a for detecting the left end of the front edge of document 10 supplied to sensor 42, and a sensor 42a.
, A sensor 42b for detecting the right end of the leading edge of the B5 size sheet, and a sensor 42b for detecting the right end of the leading edge of the B5 size sheet.
It is provided at a distance equal to the width of the paper of the size,
Sensor 4 for detecting the right end of A4 size paper
2c.

A feature of the facsimile apparatus according to the present invention is that the program executed in the microcomputer 62 not only corrects the inclination of the original but also detects the direction of the character string of the original so that the compression efficiency is maximized. To
It has a function of converting a read image signal using the page memories 76 to 80.

Referring to FIGS. 9 to 15, the facsimile apparatus according to the present invention operates as follows. First, the principle of operation of the facsimile apparatus at the time of reading a document, to which the present invention mainly relates, will be described.

The operator sets a document to be transmitted on a document table (not shown) provided in contact with the feeding roller 34. The sensor 40 detects that a document has been set, and sends a signal to that effect to the sensor circuit 64. Further, the operator presses a start button (not shown) on the operation panel 18. The panel controller 66 scans each key of the operation panel 18 as described above, and thus detects that the start button has been pressed by the operator. The panel controller 66 gives a signal to that effect to the microcomputer 62.

The microcomputer 62 sends a signal from the sensor circuit 64 to the effect that the transmission original has been set, to the panel controller 6.
6 and receives a signal indicating that the start button has been pressed, and operates as follows. First, the microcomputer 62
By controlling the page memory control circuit 74, the page memory 7 is controlled.
The page memories 76 to 80 are enabled so that images can be written to 6 to 80. Microcomputer 62
Then controls the mechanics / recording control circuit 68 to
A pulse motor (not shown) for document conveyance is operated. The transport roller 36 is rotated by the pulse motor, and the document is transported in the sub-scanning direction. At this time,
The separated original is transported by the rubber plate 38 for reading.

The conveyed document passes before the sensor 42 before being read by the CCD 60. Referring to FIG. 10, it is assumed that the front edge of document 10 is inclined by angle θ with respect to the main scanning direction (perpendicular to the document conveyance direction). The document 10 is assumed to be A4 size.
Due to the inclination θ, a shift of the distance D1 occurs in the sub-scanning direction at the left end and the right end of the front edge of the document 10.

The conveyance speed of the document 10 is detected by the circuit 68, and the microcomputer 62 can know the speed in advance. The width of the document 10 is also known from the sensor output.
Therefore, by knowing the time from when the sensor 42a detects the passage of the left edge of the front edge of the document 10 to when the sensor 42c detects the passage of the right edge of the front edge of the document 10, the inclination θ can be easily known. Can be.

If the paper 10 is of B5 size, the inclination θ is determined by the signals of the sensors 42a and 42b.
You can know.

The signals of the sensors 42a to 42c are
4 given. The sensor circuit 64 includes the sensors 42a to 42a.
The output result of 42c is given to the microcomputer 62. Microcomputer 6
2 calculates the inclination θ according to a predetermined calculation.

The microcomputer 62 controls the lighting circuit 20 to turn on the fluorescent lamp 22. The light emitted from the fluorescent lamp 22 is reflected on the surface of the original and reaches the mirror 56.
The light beam reflected by the mirror 56 is transmitted to the
An image of the document is formed on the light receiving surface of D60. At this time, the positions of the lens 58 and the CCD 60 are moved by the motor 54 according to the size of the document, and the magnification of the image is adjusted. CCD
Reference numeral 60 electrically scans the image of the document in the main scanning direction, outputs an analog signal corresponding to the luminance on the surface of the document, and supplies the analog signal to the reading processing circuit 70.

The reading processing circuit 70 makes the level of the analog signal supplied from the CCD 60 constant by AGC processing, and further suppresses the optical system distortion included in the signal output from the CCD and the distortion due to the influence of the sensitivity variation of the CCD. The correction is applied to the page memory control circuit 74.

The page memory control circuit 74 detects the passage of the left edge of the front edge of the document by the sensor 42a shown in FIG.
6 is started.

Writing to the page memory 76 is performed as follows. Referring to FIG. 11, page memory 7
6 has an image storage area 82 consisting of memory cells arranged two-dimensionally in the x and y directions. The page memory 76 sequentially stores signals obtained by one main scan in one row in the y direction of memory cells at a fixed address in the x direction. The address in the x direction is incremented sequentially with the sub-scan. Therefore, the original image 84 is formed in the image storage area 82 as a group of main scanning lines in the sub-scanning direction.

Referring to FIG. 9 and FIG.
The difference between the position of the sensor 42 and the position of the original when the original is actually read by the CCD 60 is between the time when a detects the left end of the leading edge of the original 10 and the time when the CCD 60 detects the same portion. Causes a certain time difference. Therefore, as shown in FIG. 11, the leftmost end of the front edge of the document image 84 is stored at the address X1 in the x direction and the address Y1 in the y direction in the image storage area 82 of the page memory 76. Thereafter, the image of this document is stored in the page memory 76 in a form as shown in FIG.

Referring to FIG. 11, image storage area 82 of page memory 76 has addresses x _{0 to} x _n in the x direction,
It assumed to have a Y direction address y ₀ ~y _n.
Left edge address of the leading edge of the page memory 76 the original image 84 stored in the (x _1, y _1), the right end of the leading edge of the original image 84 is assumed to have an address (x _2, y _2). Address (X ₁ , Y ₁ ) and address (X ₂ , Y ₂ )
Is due to the inclination θ of the document as described above.

The inclination θ of the document is determined by the sensor 42a, the sensor 4
It can be easily obtained from the output of 2c. The microcomputer 62 converts the coordinates of the original image 84 using the obtained inclination θ, and writes the converted data in the page memory 78. This coordinate conversion is performed by using the method disclosed in US Pat. No. 4,829,452 to convert the original image 84 into a predetermined point in the image storage area 82, for example, an address (x ₀ , y ₀ ).
Is rotated around the angle θ.

As shown in FIG. 12, the data stored in the page memory 78 as a result of the coordinate conversion is such that each of the four originals is parallel to the corresponding side of the image storage area 82. As a result, when a document is supplied as shown in FIG. 11, the arrangement direction of the characters matches the y direction of the arrangement of the memory cells of the page memory.

By converting the image of the original in this way, if this image signal is read out along the y-direction of the address of the page memory, the signal is read under the same conditions as when the original is inserted at an inclination of 0. Can be compressed. Therefore, the compression efficiency of the image signal is significantly improved as compared with the case where the image signal is compressed as shown in FIG.

As shown in FIG. 10, when the original 10 is supplied in an inclined manner so that the direction of the character string 12 on the original 10 is shifted from the main scanning direction of the image by a small angle θ,
By the coordinate conversion as described above, a corrected image signal with the highest compression efficiency can be immediately obtained. However, the original is not always supplied to the facsimile machine in such a direction.

For example, referring to FIG. 13, when a vertically written original is supplied as it is to a facsimile apparatus as in Japanese, or when a horizontally written original is rotated by almost 90 degrees regardless of Japanese or English, the facsimile is rotated. When the image signal is supplied to the apparatus, the above-described correction alone does not improve the compression efficiency of the image signal. That is, if the correction is performed only by the outputs of the sensors 42a and 42c shown in FIG. 10, the image signal after the correction is merely as shown in FIG.

Referring to FIG. 14, in a document in which characters are arranged in the vertical direction, the direction of the character string does not match the y direction of image storage area 82 only by performing the above-described correction. Even if this image is read as it is along the y direction and compressed, the compression efficiency is not improved.

Therefore, the program executed by the microcomputer 62 of the facsimile apparatus according to the present invention is executed before the coordinate conversion of the image is performed based on the original inclination θ obtained by the sensors 42a and 42c as described above.
It is characterized by detecting the direction of a character string on a document. The detection of the direction of the character string is performed according to the following procedure.

First, the microcomputer 62 checks the original image stored in the page memory 76 and calculates the ratio of the white point to the black point in each part of the original image. A ratio between a white point and a black point in a region where only character strings are arranged (hereinafter referred to as a “character arrangement region”) and a ratio between a white point and a black point in a region where an image other than a character is formed Are known to have characteristic differences. Therefore, by examining the distribution of white points and black points in the original image 84, the line image 8 containing only characters
6 can be distinguished from an image area 88 in which images other than characters are formed.

Generally, it is considered that the image compression efficiency of the image area 88 does not change irrespective of the reading direction. On the other hand, as described above, the row image 8
It is known that, when encoding the area where only 6 is formed, if the original is read and encoded along the direction in which the row image 86 extends, the signal compression efficiency is significantly improved as compared with other cases. ing. Therefore, if the direction of the line image 86 included in the character array area is detected after the character array area is detected as described above, and the image signal is encoded along the direction, the code compression can be performed. Efficiency is expected to improve.

Once the character arrangement area can be specified, FIG.
The direction in which the row image 86 extends as shown in FIG. For example, Japanese Patent Laid-Open No. 2-2
No. 15269 discloses a scanner device which determines an effective image width in the main scanning direction based on continuity of black bits in the main scanning direction and the number of black bits in the sub-scanning direction. . Using the technology disclosed in this publication,
It is possible to know the general direction in which the row image 86 of the document image 84 extends. The angle between the arrangement direction of this character string and the y-axis is θ ₁ .

[0097] With reference to FIG. 15, if the angle theta ₁ is between -45 degrees and 45 degrees, the document is determined to have been supplied to the facsimile apparatus in a state as shown in FIG. 11 You. In this case, the correction of the image is performed by the sensors 42a and 42a.
It is sufficient to make a correction for the angle θ detected by c.

On the other hand, when the angle θ ₁ is between 45 degrees and 135 degrees, it is considered that the original was supplied to the facsimile apparatus in a state as shown in FIG. In this case, as described above, the angle θ by the sensors 42a and 42c
Is corrected, the original image 84 is rotated by 90 degrees about a predetermined point in the image storage area 82.
The rotated image signal is stored in the page memory 80. The original image after the 90-degree rotation is the same as that shown in FIG.

The microcomputer 62 converts the original image 84 converted into the form shown in FIG.
A process for correcting the angle θ detected by the sensors 42a and 42c is performed. The resulting image is shown in FIG.
The result is as shown in FIG. By sequentially reading and encoding this image, the image signal can be compressed with high efficiency.

In the above description, the page memory 76 for first storing the read image signal, and the angle θ ₁ between the direction of the character string and the main scanning direction is 45 ° and 135 °
A page memory 80 for storing the image signal rotated by 90 degrees and a page memory 78 for storing the finally corrected image signal are provided. However, the present invention is not limited to this. For example, by dividing one page memory area,
It is conceivable to perform the above-described correction processing. It is also conceivable to use the same page memory for different purposes.

FIGS. 16 to 23 are schematic flowcharts of programs executed by the microcomputer 62 of the facsimile apparatus of the above embodiment. The following flowchart shows a program having a structure in which the processing is divided into a plurality of subroutines and the processing is performed by calling the subroutine from the main routine. However, the structure of the program is not limited to this. For example, a similar effect can be obtained by using a program in which all the subroutines are directly incorporated into the main routine.

Referring to FIG. 16, the main routine of this program has the following structure. Step S0
At 01, the setting of the transmission original is detected by the sensor 40 (FIG. 9).

Subsequently, in step S002, necessary initial processing is performed. The control is performed in step S003
Proceed to.

In step S003, the sensor 42
(FIG. 9), that is, the sensors 42a and 42c (FIG. 10) detect the angle θ between the leading edge of the document and the main scanning direction, that is, the inclination θ of the document. The control is performed in step S004
Proceed to.

In step S004, the image information of all the documents set on the document table (not shown) is read and stored in the page memory 76 (FIG. 9). The control proceeds to step S005.

In step S 005, it is detected where the character arrangement area is in the original image stored in page memory 76. Control is step S00
Proceed to 6.

In step S006, the direction in which the characters are arranged in the detected character arrangement area is detected. Thus, the angle theta ₁ between the arrangement direction and the main scanning direction of the character is determined. Control then proceeds to step S007.

In step S007, the sensor 42
A coordinate conversion process for correcting the image inclination is performed on the basis of the original inclination θ obtained by a and 42c. If the angle theta ₁ is between -45 degrees to 45 degrees, the correction result is written into the page memory 78. When the angle θ1 is between 45 degrees and 135 degrees, the corrected image signal is written to the page memory 80. The control proceeds to step S008.

In step S008, step S008
Based on the detected angle theta ₁ at 006, the following process is performed. When the angle θ ₁ is between −45 degrees and 45 degrees, the corrected image signal is already stored in the page memory 78. Therefore, no further correction processing is performed. On the other hand, when the angle θ ₁ is 45 degrees and 13
If it is between 5 degrees, it is necessary to further rotate the image by 90 degrees. The microcomputer 62 performs a 90-degree coordinate conversion on the image signal stored in the page memory 80, and stores the converted image signal in the page memory 78.
Write to. Therefore, regardless of the angle θ ₁ , an image signal representing an image as shown in FIG. 12 is stored in the page memory 78. Control is in step S0
Go to 09.

In step S009, the data stored in the page memory 78 is read out sequentially, encoded, and transmitted. When the transmission process ends, the program ends.

Referring to FIG. 17, in the initial processing in step S002, the following processing is performed. In step S201, it is determined whether or not a signal indicating that the start button has been pressed is given from panel controller 66 (FIG. 9). If the result of the determination is NO, the control returns to step S201 again,
Otherwise, control proceeds to step S202.

In step S202, the image memories 76 to 80 are activated so that they can be written. The control proceeds to step S203.

In step S203, the mechanics /
A signal is sent to the recording control circuit 68 indicating that conveyance of the document should be started. In response, the delivery roller 3
4. After the conveyance roller 36 starts rotating and the conveyance of the document to the reading position is started, the control returns to the main routine.

Referring to FIG. 18, the process in step S003 is performed as follows. Step S30
At 1, both ends of the leading edge of the document supplied to the reading position are detected by the sensors 42a and 42c (FIG. 10), and information on the time of the detection is notified to the program. The control proceeds to step S302.

In step S302, the sensor 42
The time difference between the detection of the original by a and the detection of the original by the sensor 42c is calculated. Control is step S303
Proceed to.

In step S303, step S
Based on the time difference obtained in 302 and the information on the paper size of the supplied original,
A look-up of a tilt table previously stored in the OM is performed. As described above, if the time difference between the detection of the original by the sensors 42a and 42c is known, the inclination θ of the original can be known according to a certain calculation formula. However, in general, the relationship between the time difference and the inclination θ is tabulated and stored in the ROM in advance. In this way, if the time difference and the document size are obtained, the inclination θ can be looked up at high speed by searching the table.

In step S304, a desired tilt angle θ is determined from the data stored in the tilt table. The control proceeds to step S305.

In step S305, the obtained inclination angle θ is stored in the memory of the microcomputer 62. Control returns to the main routine.

Referring to FIG. 19, reading of image information in step S004 is performed as follows.
In step S401, the one-page document separated by the rubber plate 38 and supplied to the reading position is
Is converted into image information, and is given to the reading processing circuit 70. The control proceeds to step S402.

In step S402, an image signal for one page input from the reading processing circuit 70 is written to the page memory 76. The control proceeds to step S403.

In step S403, it is determined whether reading of all pages has been completed. This determination is made, for example, by detecting whether or not there is a document to be read next by document sensor 40.
If the answer is no, control returns to step S401, otherwise control returns to the main routine.

Referring to FIG. 20, the detection of the character arrangement direction in step S006 is performed as follows.
In step S601, the arrangement direction of characters in the document image, the angle theta ₁ of detection formed by the main scanning direction is performed. The control proceeds to step S602.

In step S602, θ ₁ is −4.
It is determined whether the angle is between 5 degrees and 45 degrees. If the answer to the determination is NO, the control proceeds to step S603, otherwise the control proceeds to step S604.

In step S603, the flag indicating the character string direction of the document prepared in advance in the program is set to 1
Is set. Control then returns to the main routine.

If the control has proceeded to step S604, 0 is set in the aforementioned flag. Control then returns to the main routine.

As can be easily understood, when this flag is 0, the direction of the character string substantially matches the main scanning direction, and when the flag is 1, the direction of the character string matches the main scanning direction. Intersects at right angles.

The inclination correction processing in step S007 is performed as follows. In step S701, it is determined whether or not there is a tilt in the document insertion direction detected by the sensors 42a and 42c. If the answer is YES, control proceeds to step S702, otherwise control returns to the main routine.

When the control proceeds to step S702, the tilt angle θ stored in the memory in step S305 in FIG. 18 is read from the memory. The control proceeds to step S703.

In step S703, one page of image is read from page memory 76. The control proceeds to step S704.

In step S704, a correction operation for canceling the inclination angle θ is performed on the read image signal. This correction operation is performed in accordance with a well-known equation of coordinate conversion by rotation. The operation is alternatively performed according to the method described in US Pat. No. 4,829,452. The control proceeds to step S705.

In step S705, the corrected image signal is written to page memories 78 and 80. The control proceeds to step S706.

In step S706, it is determined whether a correction operation has been performed on the image signals of the originals of all pages stored in page memory 76. If the answer is no, control returns to step S703; otherwise, control returns to the main routine.

Referring to FIG. 22, the correction of the image signal based on the character arrangement direction in step S008 is performed as follows. In step S801, it is determined whether the value of the flag set in steps S603 and S604 of step S006 is 0. If the answer to the determination in step S801 is YES,
As described above, the arrangement direction of the characters on the document substantially coincides with the main scanning direction. Therefore, in this case, no correction processing is performed, and control returns to the main routine. If the answer to the determination in step S801 is NO, control proceeds to step S802.

If the control has proceeded to step S802, it means that the arrangement direction of the supplied characters on the original document is different from the main scanning direction by approximately 90 degrees. In step S802, an image signal for one page is read from the page memory 80. The control proceeds to step S803.

In step S803, a coordinate transformation for rotating the image at an angle of 90 degrees is performed on the read image signal. The control proceeds to step S804.

In step S804, step S804
The image signal corrected in 803 is stored in the page memory 7.
8 is written. The control proceeds to step S805.

In step S 805, it is determined whether or not the correction operation has been performed on the image signals of all the originals stored in page memory 80. If the answer to the determination is NO, the process returns to the control step S802; otherwise, the control returns to the main routine.

The conversion of the image signal performed in steps S007 and S008 will be described more specifically as follows. When the inclination theta ₁ is between -45 and 45 degrees, the image signal is formed in the page memory 76, it represents an image shown in FIG. 11. In this case, the image signal is converted into a signal representing a document image as shown in FIG. 12 by the correction operation performed in step S704 of step S007. In this case, the correction in the character arrangement direction in step S008 is not performed.
Therefore, the page memory 78 stores an image signal indicating a document image as shown in FIG.

On the other hand, when the inclination θ ₁ is between 45 degrees and 135 degrees, the original image represented by the image signal stored in the page memory 76 is shown in FIG. Step S
By the correction operation performed in step S 704 (FIG. 21) of 007, the page memory 80 stores an image signal representing a document image as shown in FIG.
As described above, this image signal cannot be compressed with high efficiency as it is.

In step S008, document image 84 shown in FIG. 14 is rotated by 90 degrees and written in page memory 78. Therefore, the page memory 7
The document image stored in 8 is as shown in FIG.

The transmission processing in step S009 is performed as follows. Referring to FIG. 23, step S
At 901, the microcomputer 62 sends a signal to the page memory control circuit 74 to start encoding. The control proceeds to step S902.

In step S902, the page memory control circuit 74 reads and encodes a one-page image signal from the page memory 78. The encoded signal is stored in a dedicated transfer memory (not shown). The control proceeds to step S903.

In step S903, it is determined whether or not encoding processing has been performed on all pages of the document stored in page memory 78. The answer is N
If O, control returns to step S902; otherwise, control proceeds to step S904.

If the control has proceeded to step S904, the microcomputer 62 should send the compressed signal stored in the dedicated transfer memory to the transmission control circuit 72 and the modem 30 over the telephone line. Give a signal to the effect. The transmission control circuit 72 and the modem 30 convert the compressed signal stored in the dedicated memory into an analog signal, and transmit the analog signal to the telephone line via the LIU 32 according to a predetermined procedure.
After the processing in step S904 ends, the control of the program returns to the main routine.

The encoding process of the image signal performed in step S902 is performed on the image signal representing the original image as shown in FIG. In this document image, the direction in which the character string extends and the direction in which the signal for encoding is read (main scanning direction) match. The width of the blank line between strings is the widest compared to other cases. Therefore, the blank line is efficiently encoded by the above-described makeup code, and the compression rate of the entire original is maximized.

As described above, according to the facsimile apparatus of the embodiment of the present invention, both ends of the leading edge of the supplied document are determined based on the time lag when the leading edge of the document passes in front of the predetermined sensor. The angle to make is required. The direction in which the character string extends on the document image is detected from the document image digitized by the CCD and the reading processing circuit and stored in the page memory. The image signal of the obtained document is
First, coordinate conversion is performed so as to correct the inclination of the transmitted original. The coordinate-converted image signal is further set such that the direction in which the character string on the original image represented by the image signal extends and the direction in which the image signal is read from the page memory during encoding (main scanning direction) match. If necessary, it is further rotated 90 degrees. As a result, when encoding the corrected image signal, blank lines between character strings are encoded most efficiently, and the compression efficiency of the entire original image is maximized.

Although the present invention has been described based on one embodiment, the present invention is not limited to the above-described embodiment. For example, the following embodiment is also conceivable.

The hardware of a facsimile apparatus for realizing still another embodiment of the present invention is the same as that shown in FIG. This embodiment differs from the embodiment shown in FIG. 9 in the structure of the program executed by the microcomputer 62.

Referring to FIG. 24, the program executed in microcomputer 62 of the facsimile apparatus of this embodiment has the following control structure. In step S011, it is detected whether a document to be transmitted is set on a document table (not shown). This processing is the same as the processing performed in step S001 in FIG.
The control proceeds to step S012.

In step S012, necessary initial processing is performed. This processing is the same as the processing performed in step S002 in FIG. The control proceeds to step S013.

In step S013, image information is read for all the originals set on the original platen. This processing corresponds to step S00 in FIG.
4 is the same as the processing performed in FIG. The control proceeds to step S014.

In step S014, it is detected which part of the read document image is the character array area. This processing corresponds to step S in FIG.
This is the same as the processing performed in 005. The control proceeds to step S015.

In step S015, the direction in which the character string extends in the detected character arrangement area is detected. This processing is substantially the same as the processing performed in step S006 in FIG. However, in this step S015, the direction in which the character string extends is detected more precisely than in the previous embodiment.
The control proceeds to step S016.

In step S016, a process of rotating the original image by 90 degrees based on the detected character arrangement direction so that the character string is arranged along a direction substantially coincident with the main scanning direction (if necessary). ) Done. This processing is the same as the processing performed in step S008 of the previous embodiment shown in FIG. Control is in step S0
Proceed to 17.

In step S017, the image signal corrected so that the extending direction of the corrected character string substantially matches the main scanning direction is used so that the extending direction of the character string matches the main scanning direction more accurately. Will be corrected. This process
This is almost the same as the processing performed in step S007 of the previous embodiment. However, in this case, it should be noted that, unlike the previous embodiment, the angle for correction is derived from the character arrangement direction obtained in step S015. After the processing in step S017 has been performed on the image signals of all pages, the program ends.

With the program having the above structure, the same effects as those of the above embodiment can be obtained.
That is, also in this embodiment, it is possible to compress the image signal with high efficiency regardless of the direction of the original supplied to the facsimile apparatus.

In this embodiment, the processes in step S016 and step S017 are described as separate processes. However, the invention is not so limited. For example, it is also possible to create a program so that the angle between the character arrangement direction and the main scanning direction obtained in step S015 is corrected by one operation.

In each of the above embodiments, the case of reading an image including a character string has been described. However, the present invention is not limited to this. For example, if the image includes not only a character string but also a character string in which a plurality of symbols and other characters are arranged in a certain direction, reading of the image and compression of the signal are efficiently performed by the same procedure.

[0159]

As described above, according to the image reading apparatus of the first aspect, the arrangement of the image data before encoding is determined by changing the arrangement direction of the character string in either the first direction or the second direction. The corrected image data is corrected by the correction means so as to have the same arrangement as when the image is read in a state in which it is matched with the near direction. It is configured to be. Therefore, when a document in which a character string is arranged in the first direction is input, the image data is corrected so that the character string matches the first direction, and is encoded in the first direction. When a document having characters arranged in the second direction is input, the image data is corrected so that the character string matches the second direction, and is encoded in the second direction. In any case, since the arrangement direction of the character string matches the encoding direction, the data compression efficiency of the encoded image data can be increased.

According to the image reading apparatus of the second aspect,
When the arrangement direction of the character string of the image to be read is the second direction orthogonal to the first direction, the arrangement of the read image is corrected by rotating by 90 degrees, and the arrangement direction of the character string is changed to the first direction. The arrangement is the same as that when reading is performed under the arrangement direction that matches the direction, and then the encoding is performed. Therefore, in both cases where the character string is in the first direction and in the second direction orthogonal to the first direction, data correction is performed so that the character string is arranged in the first direction. Encoding is performed in that direction. As a result, in any case, the compression efficiency of the encoding of the image data increases.

According to the facsimile apparatus of the third aspect, it is determined whether the character arrangement direction on the document is closer to the first or second direction of the arrangement of the memory cells, and if necessary, the image is predetermined. Rotated by an angle so that the character alignment direction is closer to the first direction. The signal compression means reads and encodes an image signal from the array of storage cells along the first direction. By rotating the image as described above, the average length of the white and black runs along the first direction is longer than without rotating the image, and the number of white and black runs is reduced. Generally, in a compression encoding system, one white run or one black run is one.
Is converted to one code. Therefore, according to the facsimile apparatus according to the present invention, the number of codes after compression is reduced,
Compression efficiency is improved. Also, transmission efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an image reading apparatus that is a premise of the present invention.

FIG. 2 is a flowchart showing an operation of the image reading apparatus shown in FIG.

FIG. 3 is an explanatory diagram illustrating a state in which a character string of an image is read in a state inclined with respect to a scanning direction.

FIG. 4 is a block diagram illustrating a schematic configuration of an image reading apparatus according to an embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation of the image reading apparatus illustrated in FIG. 4;

FIG. 6 is a block diagram illustrating a schematic configuration of an image reading apparatus according to another embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation of the image reading apparatus illustrated in FIG. 6;

FIG. 8 is a diagram for explaining a relationship between a character arrangement direction and a scanning direction in the operation of the image reading apparatus shown in FIG. 3;

FIG. 9 is a block diagram of a facsimile apparatus according to still another embodiment of the present invention.

FIG. 10 is a diagram schematically illustrating an arrangement of sensors for detecting a leading edge of a document supplied to a facsimile apparatus.

FIG. 11 is a schematic diagram of a document image stored in a page memory.

FIG. 12 is a schematic diagram of a document image stored in a page memory.

FIG. 13 is a schematic diagram of a document image stored in a page memory.

FIG. 14 is a schematic diagram of a document image stored in a page memory.

FIG. 15 is a diagram schematically illustrating an angle between a direction of a character string of a document and a main scanning direction.

FIG. 16 is a flowchart of a main routine of a program executed by a microcomputer of the facsimile apparatus according to one embodiment of the present invention.

FIG. 17 is a flowchart of an initial process.

FIG. 18 is a flowchart of a document inclination detection process.

FIG. 19 is a flowchart of reading image information.

FIG. 20 is a flowchart of a routine for detecting a character arrangement direction.

FIG. 21 is a flowchart of tilt correction.

FIG. 22 is a flowchart of a character arrangement direction correction routine.

FIG. 23 is a flowchart of a transmission process routine.

FIG. 24 is a flowchart of a main routine of a program executed in a microcomputer of the facsimile apparatus according to still another embodiment of the present invention.

FIG. 25 is a schematic view of a document.

FIG. 26 is a schematic diagram of a document.

FIG. 27 is a diagram illustrating a part of a terminating code included in the MH code.

FIG. 28 is a diagram illustrating a part of a makeup code included in the MH code.

FIG. 29 is a schematic diagram of a document.

[Explanation of symbols]

 Reference Signs List 1 scanner 2 binarization unit 3 image memory 4 inclination detection unit 5 inclination correction unit 6 encoding unit 7 control unit 10 original 16 control circuit 40 original sensors 42, 42a to 42c original end sensor 60 CCD image sensor 62 microcomputer 104 vertical / Horizontal detection unit 105 Rotation processing unit 106 Encoding unit 108 Inclination angle detection unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N 1/387-1/393 H04N 1/04-1/207

Claims (3)

(57) [Claims] An image reading apparatus that scans an image in a certain direction and reads the image, and encodes the read image data, extracts a character string portion in which a plurality of characters are arranged in a predetermined direction from the image. An arrangement direction detecting means for detecting the arrangement direction of the character string, and the detected arrangement directions are determined by first and second predetermined directions.
Direction determining means for determining which of the directions is closer, correction means for correcting the inclination of the image to the first or second closer direction based on the direction determining means, An image reading apparatus comprising: an encoding unit that encodes the corrected image data in the direction determined by the direction determination unit. 2. An image reading apparatus which scans an image in a predetermined direction and reads the image, and encodes the read image data, detects a character string portion in which a plurality of characters are arranged in a predetermined direction in the image. Arrangement direction detecting means for detecting an arrangement direction of a character string; and direction judging means for judging which of the first and second directions orthogonal to each other is predetermined. Correction means for rotating the read image data of one image by 90 degrees when the determination means determines that the image data is close to the second direction; and when the determination means determines that the image data is close to the second direction. The image data corrected by the correction means is encoded in the first direction, and if the determination means determines that the image data is close to the first direction, the image as read which is not corrected by the correction means is read. Image reading apparatus characterized by comprising an encoding means for encoding over data in the first direction. 3. A pixel for generating a pixel signal indicating the luminance of each pixel by dividing an image on a document into a plurality of two-dimensionally arranged pixels and reading the divided pixels. A signal generation unit; a pixel signal storage unit including a plurality of storage cells each for storing the pixel signal in a logically associated manner with one of the pixels; and the plurality of storage cells, Corresponding to the arrangement of the plurality of pixels, are logically and two-dimensionally arranged in a predetermined first direction and a second direction intersecting the first direction. Based on the stored pixel signal, a character array direction indicating an array direction in the array of the plurality of storage cells of a character string included in the image on the document represented by the stored pixel signal is changed. Character array direction detection method for detecting A step, a character arrangement direction judging means for judging which of the detected character arrangement directions is closer to the first direction and the second direction, and an output of the character arrangement direction judgment means Responsive to the character arrangement direction, when the character arrangement direction is closer to the second direction than the first direction, the image on the document represented by the stored pixel signals is converted to the character arrangement direction. Image rotation means for rotating the image on the document represented by the stored pixel signals by a predetermined angle so that the image direction is closer to the first direction, and the image rotation means Further, the stored pixel signal is read out from the pixel signal storage means along the first direction, and is compressed by a compression code. A facsimile apparatus including a transmission unit for transmitting a pixel signal to another station via a communication line.