JP2001016428A - Image forming device and transferred image distortion correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically correct an image distortion since an original which is set is not a sheet shape and to provide appropriate output image data. SOLUTION: An area at a right end, in which original picture data does not exist and which is scanned wastefully, is filled with actual original picture data by enlarging an area where a back cover where a distortion occurs is positioned along an auxiliary scanning direction. Namely, data whose width where the distortion occurs is M is mapped to the length of M+W-L by using a texture mapping algorithm when the width of a distortion area where the back cover is positioned is M. A center part where the distortion is adjusted is corrected and the right end which is excessively read is filled with actual original picture data by inserting the left end of mapped original picture data into picture data which is read by adjusting it to the left side of the distortion area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for correcting distortion of image data and a transferred image distortion correcting method, and more particularly, to optically reading a non-sheet document such as a book or an information magazine by a copying machine or the like. The present invention relates to an image forming apparatus having an automatic correction function for a transfer image distortion generated at a joint portion of a document when converting the image data into image data using the apparatus, and a transfer image distortion correction method.

[0002]

2. Description of the Related Art Conventionally, when an original image is optically read by an optical reading device and the read original image is output as a hard copy, in order to have no distortion in a transferred image, a reading unit in the optical reading device is used. It is assumed that the original is in the form of a paper sheet and that the original is completely in close contact with the original table.

Here, in a form of contact between a document and a document table by a general optical reading device, as shown in FIG. 1, a document is placed on a document table and read optically by a reading scanner. I do.

However, when the original is a non-sheet original such as a book or an information magazine, as shown in FIG.
There is a phenomenon that a gap is generated between a document and a document table.

In this case, in the "distortion area" shown in FIG. 1, in the gap between the original and the original table, there is distortion in the original image as viewed from the scanner. Further, since the bulge of the document makes it impossible to completely close the light-shielding pressure plate unit, image distortion occurs in an area corresponding to the distortion of the document in the output data of the hard copy.

[0006] Books and information magazines are generally compliant with JIS.
Because the original is distorted, the original width is shorter than the standard width in a direction perpendicular to the distorted axis because the original is distorted because it is created according to the paper size standard, as shown in FIG. A margin area unrelated to the document is also read as image data. As a result, there is a problem that a band-like distortion occurs in a corresponding portion of the output hard copy.

Due to the problems described above, if the original is not a paper sheet but a non-sheet original such as a book or an information magazine, it is possible to obtain output image data that faithfully reproduces the original image data. Impossible.

[0008] Conventionally, as a technique for correcting the read image data, the following technique can be cited.

First, Japanese Patent Application Laid-Open No. Hei 8-25
No. 1387 discloses a digital copying machine capable of automatically obtaining a hard copy corrected to a state where the original image is not inclined even if the original image is set inclined.

The digital copying machine according to the prior art 1 is
By specifying the processing mode of the inclination correction mode by the operation unit, the inclination detecting unit detects the inclination of the original image with respect to the image data obtained by photoelectrically converting the original image optically read by the original reading unit, and It is stated that the correction means corrects the image data based on the detected tilt amount and outputs the corrected image data to the output means, thereby obtaining a hard copy corrected to have no tilt.

However, in the prior art 1,
This is for correcting a tilt generated when a document is set, and cannot correct a distortion caused by a shape of the document itself. That is, in order to correct the tilt, only the angle of the tilt needs to be detected, and correction according to the detected tilt may be performed. However, when correcting the distortion of the read image data caused by the distortion of the original document itself, Must detect the area of the distortion, detect the degree of the distortion, and perform the correction.

Further, as a prior art 2, Japanese Patent Laid-Open No. 8-31
Japanese Patent Application Laid-Open No. 7196 discloses a digital color copier that improves the gradation of a monitor display image and eliminates image deletion such as fine lines and small dots.

A digital color copier according to the prior art 2 includes a scanner for optically reading a document and outputting the image data as image data, an image processing unit for performing predetermined image correction and editing processing on the image data read by the scanner,
A color image forming apparatus including a printer that records image data processed by the image processing unit on recording paper,
A conversion unit that inputs image data from a scanner, extracts a maximum value of n × n pixels of the image data, and converts the maximum value into a thinned image; and a memory that stores the thinned image generated by the conversion unit. A display panel for multi-value display of the thinned image data stored in the memory, and further, by rotating and converting the coordinates of the read image data, the user can expect even if the original direction and the display direction are different. It is stated that a display image in a direction without a sense of discomfort can be obtained.

However, in the prior art 2,
Multi-valued display of thinned image data prevents erasure of images such as fine lines and small dots, and rotationally transforms image data to display thin lines and small dots when displaying read image data. This is a technique for preventing the document from becoming invisible, and does not correct the distortion of the read original image data caused by the distortion of the original document which the present invention does not solve.

As prior art 3, Japanese Patent Application Laid-Open No. 9-18 / 1990
In Japanese Patent Application Laid-Open No. 5227, a latent image is erased in consideration of shadows due to the thickness of a document, detection errors of the document outline, erase control errors, and errors in alignment between a transfer sheet and a photosensitive member image. An eraser of a copying machine capable of obtaining a figure is disclosed.

The erasing device for a copying machine according to the prior art 3 is an eraser for a copying machine for erasing an unnecessary area outside a document, and an eraser for erasing a latent image in an unnecessary area on a photosensitive member.
An ED array is provided, and the LED array is positioned between the original image writing device and the developing unit so as to cross in the direction perpendicular to the rotation direction of the photoconductor, so that the reflection density of the original pressure plate is higher than the original background reflection density. By making the density lower than the internal reflection density, the document contour detection sensor detects the position and contour of the document set on the document table in comparison with the reflection density of the document pressure plate. Eraser LED corresponding to the latent image on the photoconductor based on the result
By controlling the blinking of the image, the latent image is erased, and a good copy image without original shadow is obtained.

However, in the prior art 3,
A problem that can be solved by controlling the blinking of the LED array is a latent image in the case where the document has irregularities. This technology is caused by distortion of the document itself as in the above-described related arts 1 and 2. It does not correct the distortion of the read original image data.

Japanese Patent Application Laid-Open No. 9-28 is a prior art.
Japanese Patent No. 4557 discloses an image forming apparatus that eliminates white spots in an image due to overflow of a CCD caused by reflected light when copying a luminous object such as metal by a copying machine.

The image forming apparatus according to the prior art 4 employs a CC
By setting a white level and a black level when reading an original in accordance with D in advance, the output of the CCD is digitized as 10-bit data, and up to 8 bits of the data are converted to a video signal of the above-mentioned white level set value. When an overflow is detected, the data of the upper two bits of the target pixel is converted to the image correction circuit 134 using the data of the neighboring pixels.
The correction is made to correct the overflow of the CCD due to the reflected light.

However, in the prior art 4 as well,
As in the above-described prior arts 1 to 3, it does not correct the distortion of the read original image data caused by the distortion of the original document itself.

[0021]

As described above, the correction of the read image data according to the prior art is a correction technique on the premise that all the sheet-like originals are read, and is based on the non-sheet-like original. There is a problem that a technique for correcting distortion of image data depending on distortion of a shape has not been established.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is an object of the present invention to automatically correct an image distortion caused by a set document not being a sheet-like document and obtain an appropriate output image data. An object of the present invention is to provide a forming apparatus and a transferred image distortion correction method.

[0023]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a distortion detecting means for detecting distortion of image data, and a predetermined correction for the distortion detected by the distortion detecting means. And a correction processing means for performing

According to a second aspect of the present invention, there is provided reading means for optically reading a document image as image data, storage means for temporarily storing the read image data, and distortion detecting means for detecting distortion of the image data. Correction processing means for performing a predetermined correction on the image data stored in the storage means based on the distortion detected by the distortion detection means, and print output for printing out the image data corrected by the correction processing means Means.

According to a third aspect of the present invention, in the image forming apparatus of the first or second aspect, there is provided a pattern registration means for registering a distortion pattern caused by the shape of the document.
A distortion calculating unit that calculates a degree of the distortion detected by the distortion detecting unit based on the registered pattern, wherein the distortion correcting unit determines a predetermined degree based on the degree of the distortion calculated by the distortion calculating unit. It is characterized in that the degree of correction is changed.

According to a fourth aspect of the present invention, in the image processing apparatus according to any one of the first to third aspects, the size of the document is stored in advance from the side where the length does not change due to the distortion of the image data. The image processing apparatus further includes a size specifying unit that selects from the size of the transfer paper, and the predetermined correction performed by the correction processing unit includes a process of adjusting the size of the image data to the size of the transfer paper.

According to a fifth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to fourth aspects, further comprising a document area specifying means for specifying a document image data area of the image data. The predetermined correction by the means includes a process of interpolating the area specified by the document area specifying means to the size of the transfer paper to be transferred.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, there is further provided a distortion area specifying means for specifying a distortion area of the image data.
Image data obtained by reading a book or an information magazine, the distorted area is positioned so as to be sandwiched between areas where there is no distortion in the image data, and interpolation is performed when the area where the distortion of the image data does not exist in the transfer paper size. The distortion area is corrected so as to be located at both ends of the transfer paper size.

According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, a user inputs a setting as to whether or not to correct distortion included in the read image data. Operating means for performing the predetermined correction when the setting for correcting the distortion is made by the operating means.

According to an eighth aspect of the present invention, there is provided the image forming apparatus according to any one of the fifth to seventh aspects, wherein the next and subsequent scans are performed based on the original image data area calculated by the original area specifying means. It is characterized by further comprising a scanning range adjusting means for adjusting the range.

Further, the invention according to claim 9 has a distortion detecting step of detecting distortion of image data, and a correction processing step of performing a predetermined correction to the distortion detected in the distortion detecting step. I do.

Further, according to a tenth aspect of the present invention, there is provided a reading step of optically reading a document image as image data, a storing step of temporarily storing the read image data, and a distortion detecting step of detecting distortion of the image data. A correction processing step of performing predetermined correction on the image data stored in the storage step based on the distortion detected in the distortion detection step, and a print output for printing out the image data corrected in the correction processing step And a process.

[0033] The invention described in claim 11 is the same as the ninth aspect.
Or the image forming method according to 10, further comprising, after the distortion detecting step, a distortion calculating step of calculating a degree of the distortion detected by the distortion detecting step based on a distortion pattern generated by a shape of the document registered in advance. The distortion correcting step is characterized in that a predetermined degree of correction is changed according to the degree of distortion calculated in the distortion calculating step.

The invention according to claim 12 is the invention according to claim 9
In the image processing method according to any one of Items 1 to 11, when the distortion is detected in the distortion detecting step, the transfer paper in which the size of the original is stored in advance from the side where the length does not change due to the distortion of the image data. And the predetermined correction in the correction processing step includes a process of adjusting the size of the image data to the transfer paper size.

Further, the invention of claim 13 provides the invention of claim 9
13. The image forming method according to any one of items 1 to 12, further comprising, after the distortion detecting step, a document area specifying step of specifying a document image data area of the image data. The method includes a process of interpolating the area specified by the process to the size of the transfer paper to be transferred.

The invention according to claim 14 is the first invention.
3. In the image forming method according to 3, after the document area specifying step,
The image processing apparatus further includes a distortion region specifying step of specifying a distortion region of the image data, wherein the image data is image data obtained by reading a book or an information magazine, and the distortion region is sandwiched between regions where there is no distortion of the image data. In the interpolation, the area where there is no distortion of the image data in the transfer paper size is
It is characterized in that the distortion area is scaled up and down so as to be located at both ends of the transfer paper size.

The invention according to claim 15 provides the invention according to claim 9
The image forming method according to any one of to 14, further comprising an operation step for inputting a setting as to whether or not to correct distortion included in the read image data by a user,
The distortion detecting step is characterized in that a predetermined correction is executed when a setting for correcting the distortion is made in the operation step.

The invention according to claim 16 is the first invention.
In the image forming method according to any one of 3 to 15,
The scanning range for the next and subsequent readings is adjusted based on the document image data area calculated in the document area specifying step.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus and a transferred image distortion correcting method according to the present invention will be described below in detail with reference to the drawings.

First, referring to FIG. 1, conventionally, when a non-sheet-shaped document 101 is brought into contact with a document table 102 and image data is read, a gap is provided between the document 101 and the document table 102 as shown in FIG. Occurs. Assuming that a region where the gap is generated is a distortion region, the document 101 is viewed vertically from the surface of the document table 102, and in this distortion region,
Since the user views the document from an oblique direction, the captured document image data is distorted.

In the case of a document conforming to the JIS paper size standard, a margin area is generated due to distortion of the document 101 itself. The margin area is a non-sheet-shaped original 101.
In the case of a book or an information magazine as shown in FIG. 1, JIS paper is obtained by apparently reducing the valley line between pages in a distorted area in the vertical direction due to distortion in the spine. This area is generated for an original size expected for a size standard original.

In order to correct the distortion caused by the above-mentioned non-sheet original, the image forming apparatus and the transferred image distortion correcting method according to the present invention have the configuration as shown in FIG. 2 in one embodiment.

FIG. 2 is a block diagram showing the configuration of an embodiment in which the image forming apparatus and the transferred image distortion correcting method according to the present invention are applied to a digital copying machine.

Referring to FIG. 2, a digital copying machine according to an embodiment of the present invention includes a reading section 201 for reading an original image, an input image memory 202 for storing the read original image data, and The image processing unit 203 includes an image processing unit 203 that executes a process including a process of detecting and correcting the included distortion and an output unit 204 that outputs the corrected document image data.

Here, the flow of operation in the embodiment shown in FIG. 2 will be described in detail with reference to the flowchart of FIG.

In FIG. 3, in step S301, the original is exposed by the reading unit 201, and in step S30
In 2, the photoelectric conversion is realized by measuring the intensity of the reflected light from the document by the scanner. The document image data obtained in this way is stored in the input image memory 202 in step S303.

The original image data obtained by the reading unit 201 is sent to the image processing unit 203. Image processing unit 20
3, the operation panel 2 is operated based on the original image data.
Image correction and image processing are performed with reference to various options such as the paper size, output image density, output number, and the presence or absence of a correction mode determined in step S05.

In this image processing, when a correction mode is specified, a distortion region is detected in a distortion detection process in step S304, and distortion is corrected in a distortion correction process in step S305.

In step S306, the original image data thus corrected is temporarily stored in the input image memory. Further, the output unit 204 receives the processed image data of the original document sent from the image processing unit 203, and in step S307, actually records the image data on a recording sheet by using a laser writing technique and an electrophotographic process (step S308). .

FIG. 4 is a flowchart showing in more detail the flow of the distortion correction processing operation of the image processing section 203 in the configuration of the present embodiment shown in FIG.

As shown in FIG. 4, the user sets whether the correction mode is valid or invalid by using a correction mode button set on the operation panel 205, and the image processing unit 203 determines the presence or absence of the correction based on the setting. Here, when the non-correction mode is set, the image processing unit 203 performs a normal process on the read document image data without performing any correction, and outputs the data from the output unit 204. On the other hand, when the correction mode is set, the following correction is performed on the read document image data, and the data is output from the output unit 204.

Hereinafter, the image processing unit 2 which is a feature of the present invention will be described.
The processing in the correction mode in 03 will be described in detail with reference to the drawings.

As shown in FIG. 1, when the original is non-sheet-shaped such as a book or an information magazine, a bend occurs between the pages of the original, and the light shielding unit is not completely closed. The scanning light applied to the distorted area which is the middle part of the image data is not reflected, and this part of the read image data becomes black.

In addition, since the width of the original in the direction perpendicular to the valley line between the pages is shorter than the reference value determined by the JIS standard or the like, the scanning light in the margin area, which is the rightmost part of the scanning, is used. Are not reflected in the same manner, and become black like the distorted area.

Therefore, referring to FIG. 5, as the distortion pattern, the strength of the edge of the image data is examined from the center line of the captured original image parallel to the main scanning direction to the left and right parallel to the sub-scanning direction. This is determined by specifying the region surrounded by the line segment of the peak at the edge exceeding the predetermined threshold for the first time on both the left and right sides. This area is a distortion area in the center of the document, that is, a distortion area of the document image data due to the distortion of the document due to the joining of the pages. Also,
When viewed along the sub-scanning direction, a region surrounded by a line similar to the second line in the right direction is also a distortion region. However, this second distortion region is a margin region.

Accordingly, in the document of each size, a list for three areas, that is, the area of the area to the left and right from the center line, which is the spread valley line, and the area of the rightmost extra read distortion area are set. By preparing in advance, a distortion pattern can be determined.

The data for the three areas prepared in advance are input to the copying machine system. Furthermore, the size of output recording paper that can be handled by the copier system in advance,
The vertical and horizontal dimensions are entered according to the JIS paper size standard, and are stored in a copier as a standard size table. Thus, when the correction mode is set, the following processing can be performed.

First, an area where distortion is present in the read original image data is detected. In this process, as shown in FIG. 5, in the read original image data,
A width S is provided at both ends in the main scanning direction, and a change in luminance with respect to an adjacent pixel, so-called edge strength, is calculated for each image pixel repeatedly within the range of the width S along the sub-scanning operation direction. The calculation method is shown below.

Here, the coordinate value of the pixel of interest is (i,
In j), if the luminance value is p, the corresponding edge value is e (i, j), and the calculation steps are as follows.

Down = p (i, j) + p (i + 1, j); up = p (i, j + 1) + p (i + 1, j + 1); left = p (i, j ) + p (i, j + 1); right = p (i + 1, j) + p (i + 1, j + 1); dx = 0.5 * (right-left); dy = 0.5 * (up- down); e (i, j) = sqrt (dx * dx + dy * dy) (Equation 1)

The edge e (i,
By the calculation of j), an edge map in the captured original image data can be obtained. This defines the threshold value α of the edge on the sub-scanning line.

On the basis of the specified threshold value α, an edge map is used in the left direction (the direction opposite to the sub-scanning line) with each pixel at the right end of the read original image data as the start point of each sub-scanning line. The edge strength of each pixel is equal to the threshold α
Check to see if it exceeds.

Here, the pixel having the first appearing edge value larger than the threshold value α and taking the peak value is defined as the right corner of the document. Further, in order to prevent an error, the calculation of whether or not to take a peak value uses three pixels adjacent to the target pixel on the left and right.

An axis parallel to the sub-scanning direction is set as a horizontal axis, and a horizontal axis coordinate x of a center point of a pixel which takes a peak value is recorded. Thus, a one-column matrix in which the coordinates x are elements is obtained.
Here, in FIG. 5, by setting the distance L from the origin of the sub-scanning line to the maximum value of the coordinate x as the length of the document, a point corresponding to a half of L is the center point of the read document image data. Becomes

From this center point, the edge value of each pixel is examined so as to spread to the left and right along the sub-scanning line, and the pixel which exceeds the threshold α for the first time on the left and right and contains the peak of the edge is detected. Is determined to be a distortion region.

In the read original image data shown in FIG. 5, a shaded portion is a portion where image distortion has occurred. Generally, the value of S is set at 10% of the document width, but the present invention is not limited to this value.

As described above, for the first time, the threshold α
When a region surrounded by pixels detected to exceed the peak of the image and including an edge peak is determined to be a distorted region, a distorted region is detected. Determine the size of

Here, when the output paper size is designated on the operation panel, it can be estimated that the original size of the read original is equal to the designated output paper size. However, when the output paper size is not specified, as shown in FIGS. 1 and 4, the size is smaller than the standard size W because the size is reduced by the thickness of the document in the sub-scanning direction. On the other hand, since the original size H in the main scanning direction does not change,
The document size to be actually read is estimated by the following procedure.

H in FIG. 5 is used as a base in the comparison of the read original size, and this base H is compared with each vertical width of a standard size table built in the copying machine prepared in advance. Here, the allowable error is set to 10%, and all the candidates included in the allowable error range are extracted from the standard size table. Then, using the extracted candidates, the width L of the image actually read and the width of the candidate are compared, and the one having the smallest difference is determined as the estimated standard width W of the output image.
And

By performing the above-described operations, the size of the document image to be output can be adjusted to the size conforming to the JIS standard paper size standard.

Here, when scanning the next page, assuming that the scanning distance is L, the distortion level is clearly L
And W. That is, the larger the difference between L and W, the wider the range of distortion. Also, whether or not image correction is necessary is determined based on this difference, so that appropriate determination can be made.
For example, if the difference between L and W is 5% or more,
Assume that image correction is required.

Hereinafter, a method for correcting a detected image distortion according to an embodiment of the image forming apparatus and the transferred image distortion correction method according to the present invention will be described in detail with reference to the drawings.

A method for correcting image distortion according to the present embodiment will be described with reference to the diagram shown in FIG.

In FIG. 6, the length of the image data in the sub-scanning direction is shorter than the standard width of the original because distortion occurs at the center line portion which is the page joining portion of the read image data. This is because the document is read in a state where the center line portion, which is the page joining portion of the document, is contracted, and the actual document image data is not contained in the rightmost portion.

Therefore, by expanding the area where the backstrip where the distortion has occurred is located in the sub-scanning direction, an extra scanned area at the right end where there is no original image data is filled with actual original image data.

That is, assuming that the width of the distorted area where the spine is located is M, the data having the distorted width of M is mapped to the length of M + W-L using the texture mapping algorithm. As a result, the left end of the mapped document image data is aligned with the left side of the distortion area and inserted into the read image data.

By the above-described operation, the middle portion where the distortion has been corrected is corrected, and the extra right end read can be filled with the actual original image data.

[0078]

As described above, by designating the distortion correction mode as the processing mode in the designation section, even if there is distortion in the image data read by the non-sheet original, this distortion region is eliminated. It is possible to obtain a hard copy that is automatically detected and corrected to a state close to the time when a paper sheet without distortion is set, thereby improving the appearance of the copy finish.

Further, by inputting an image distortion pattern based on a non-sheet-shaped original image from the outside to the system, the original data (list) for detecting distortion in the operation of the image data distortion automatic detection means is standardized. It is possible to apply to what has been converted.

Further, by judging whether or not the distortion detected by the image data distortion automatic detection means exceeds a threshold value, it is possible to automatically select the presence or absence of the distortion, thereby preventing erroneous correction.

Further, in the original image data obtained by the original reading means, the input image size is estimated based on the JIS standard, so that the size of the output image can be adjusted to the JIS standard.
It becomes possible to match with those conforming to the standard.

Further, by determining the document area in the document image data obtained by the document reading means, data interpolation of the non-document area can be performed.

Further, by adjusting the scanning range for reading based on the document area calculated by the document area determining means, it is possible to improve the copying speed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a form of a document placed on a document table.

FIG. 2 is a block diagram illustrating a configuration of an image forming apparatus according to the present invention.

FIG. 3 is a flowchart illustrating a flow of an operation in an embodiment of the image forming apparatus according to the present invention.

FIG. 4 is a flowchart illustrating a processing flow in an embodiment of the image forming apparatus according to the present invention.

FIG. 5 is a diagram illustrating an example of document image data read via a document table.

FIG. 6 is a diagram showing a specific example of correction by processing in an embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

 101 Document 102 Document Table 103 Scanning Unit 201 Reading Unit 202 Input Image Memory 203 Image Processing Unit 204 Output Unit 205 Operation Panel

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/107 F term (Reference) 2H027 DB01 DB09 DC19 DE07 EC11 EE08 FB13 FC03 FD01 FD02 FD03 FD08 5B057 AA11 BA02 BA21 BA30 CA02 CA06 CA12 CA16 CB02 CB06 CB12 CB16 CC03 CD05 CD12 CH11 CH18 DA08 DA17 DB02 DB05 DB08 DC31 5C072 AA05 BA17 LA17 MB04 RA04 RA06 UA11 UA13 UA20 VA06 XA01 5C076 AA21 AA22 AA40 BA01 BA03 BA02 BA07 CA10 CB

Claims (16)

[Claims] 1. An image forming apparatus comprising: a distortion detecting unit that detects a distortion of image data; and a correction processing unit that performs a predetermined correction on the distortion detected by the distortion detecting unit. Reading means for optically reading a document image as image data; storage means for temporarily storing the read image data; distortion detecting means for detecting distortion of the image data; A correction processing unit configured to perform a predetermined correction on the image data stored in the storage unit based on the detected distortion; and a print output unit configured to print out the image data corrected by the correction processing unit. An image forming apparatus comprising: 3. A pattern registering means for registering a pattern of distortion caused by the shape of a document, and a distortion calculating means for calculating a degree of distortion detected by the distortion detecting means based on the registered pattern. The image forming apparatus according to claim 1, wherein the distortion correction unit changes the degree of the predetermined correction according to the degree of distortion calculated by the distortion calculation unit. 4. The image processing apparatus according to claim 1, further comprising: a size specifying unit that selects a size of the document from a size of transfer paper stored in advance from a side where a length does not change due to the distortion of the image data. 4. The image processing apparatus according to claim 1, wherein the predetermined correction includes a process of adjusting the size of the image data to the size of the transfer sheet. 5. The apparatus according to claim 1, further comprising: a document area specifying unit for specifying a document image data area of the image data, wherein the predetermined correction by the correction unit is performed by transferring an area specified by the document area specifying unit. 5. The method according to claim 1, further comprising a process of interpolating to a transfer paper size.
The image forming apparatus according to any one of the above. 6. The image data further includes a distortion area specifying unit that specifies a distortion area of the image data, wherein the image data is image data obtained by reading a book or an information magazine, and the distortion area includes a distortion of the image data. The interpolation corrects the distorted area such that the area where the image data is not distorted in the transfer paper size is located at both ends of the transfer paper size. The image forming apparatus according to claim 5, wherein: 7. An operation unit for inputting a setting as to whether or not to correct a distortion included in the read image data by a user, wherein the distortion detecting unit is configured to correct the distortion by the operation unit. The image forming apparatus according to claim 1, wherein the predetermined correction is performed when the correction is performed. 8. The apparatus according to claim 5, further comprising: a scanning range adjusting unit that adjusts a scanning range for the next and subsequent readings based on the document image data area calculated by the document area specifying unit. An image forming apparatus according to any one of the above. 9. An image forming method comprising: a distortion detecting step of detecting distortion of image data; and a correction processing step of performing a predetermined correction on the distortion detected by the distortion detecting step. 10. A reading step of optically reading a document image as image data; a storing step of temporarily storing the read image data; a distortion detecting step of detecting a distortion of the image data; A correction processing step of performing a predetermined correction on the image data stored in the storage step based on the detected distortion; and a print output step of printing out the image data corrected by the correction processing step. An image forming method comprising: 11. A distortion calculating step for calculating a degree of distortion detected in the distortion detecting step based on a distortion pattern generated by a shape of a document registered in advance after the distortion detecting step, 11. The image forming method according to claim 9, wherein in the distortion correction step, the predetermined degree of correction is changed according to the degree of distortion calculated in the distortion calculation step. 12. When the distortion is detected in the distortion detecting step, the size of the original is selected from the size of the transfer paper in which the size of the document is stored in advance, from the side where the length does not change due to the distortion of the image data. 12. The image according to claim 9, further comprising a specifying step, wherein the predetermined correction in the correction processing step includes a process of adjusting the size of the image data to the transfer paper size. Processing method. 13. The method according to claim 13, further comprising: after the distortion detection step, a document area specifying step of specifying a document image data area of the image data, wherein the predetermined correction by the correction step is specified by the document area specifying step. 10. The method according to claim 9, further comprising a process of interpolating the set area to a size of a transfer paper to be transferred.
3. The image forming method according to any one of 2. 14. The method according to claim 14, further comprising: after the document area specifying step, a distortion area specifying step of specifying a distortion area of the image data, wherein the image data is image data obtained by reading a book or an information magazine. Is positioned so as to be sandwiched between regions where the image data has no distortion, and the interpolation is performed such that the region where the image data has no distortion in the transfer paper size is positioned at both ends of the transfer paper size. 14. The image forming method according to claim 13, wherein the distortion area is corrected by scaling. 15. A user further comprising an operation step for inputting a setting as to whether or not to correct distortion included in the read image data, wherein the distortion detecting step includes a setting for correcting distortion by the operation step. 15. The image forming method according to claim 9, wherein the predetermined correction is performed when the correction is performed. 16. The scanning range for the next and subsequent readings is adjusted based on the document image data area calculated in the document area specifying step.
5. The image forming method according to any one of 5.