JPH07273979A - Method and device for image processing - Google Patents

Abstract

PURPOSE:To obtain an enlarged image of high quality by preparing two kinds of subscanning-directional enlarging means which are a method for mechanical enlargement and a method for electrical complementary enlargement after pseudo unmagnified processing for an image reader, and switching those two kinds of method at proper time according to the kind of a document and the read mode of an image. CONSTITUTION:When an original image is enlarged, the image is read out by making the speed of scanning in the direction perpendicular to the array direction of an image sensor slow according to a variable magnification rate. When the enlargement rate is >=150%, image data of an optional pixel array in the image sensor array direction in image information read by the image sensor are supplied to and thinned out by a subscanning thinning-out circuit 71, and then the edge is emphasized by an edge processing circuit 72. Then the optional pixel array in the read image information is complemented and enlarged by a main scanning complementary enlarging circuit, and then complemented and enlarged by a subscanning complementary enlarging circuit 74 when already thinned out in the subscanning direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more particularly to an image processing method and apparatus for performing predetermined image processing such as image scaling processing on image data obtained by reading an original image.

[0002]

2. Description of the Related Art Conventionally, when an original is enlarged and read by an image processing apparatus (image reading apparatus) of this type, the read image is electrically complemented and enlarged in the main scanning direction (pixel array direction of the line image sensor), and the sub image In the scanning direction (movement direction of the line image sensor), electrically, complementary enlargement is performed.

For example, as an electrically supplementary enlargement method in the sub-scanning direction, the scanning speed of the line image sensor is slowed as compared with the normal case, and pixel data in the array direction of the line image sensor is thinned out, so as to be pseudo. After returning to the double-size image, the image is magnified and read by electrically performing the complementary enlargement as in the case of the main scanning direction. By performing such reading, it is possible to make the transfer frequency of the image data constant regardless of the scaling factor, and it is easy to read and output the read image in accordance with the processing timing of the processing device side by using a buffer memory or the like. This is possible without adding any additional hardware. Particularly in the case of a copying machine, the memory cost can be reduced by matching the transfer frequency of the image data with the image forming process speed of the printer section.

[0004]

However, when the original image is enlarged by the method of the above-mentioned conventional example, there are the following drawbacks. That is, in order to electrically enlarge and complement both the main scanning direction and the sub-scanning direction, the image data once read in the sub-scanning direction is thinned to reproduce the edge component.
The edge component in the sub-scanning direction may remain stronger than it should be. Therefore, when a document is composed of halftone dots and fine lines, a moire occurs in the sub-scan due to interference between the insertion period of complementary data according to the enlargement ratio and the halftone dot or thin line λ period of the document. was there.

Further, as another enlargement method, when the enlargement processing in the sub-scanning direction is performed by only slowing down the scanning speed of the line image sensor as compared with the normal case, particularly when a large enlargement ratio is taken, If you try to add edge processing such as edge enhancement or black character processing to the scanned image,
Since the image is read at a slower scanning speed in the sub-scanning direction, the edge component in the read original image becomes weaker than in the normal-size reading. On the other hand, in the main scanning direction, since the supplementary enlargement processing is electrically performed on the read image, the edge component does not become weak.

Therefore, when the edge processing is performed on the enlarged and read image data, there is a drawback that the processing takes a little in the sub-scanning direction and the processing takes differently in the main scanning direction and the sub-scanning direction. . In order to prevent this, there is no choice but to prevent edge processing.

[0007]

The present invention has been made for the purpose of solving the above-mentioned problems, and is provided with, for example, the following structure as one means for solving the above-mentioned problems. That is, in an image processing apparatus that scans a line image sensor to read an original image and performs a predetermined scaling process on the read image information, the scan speed in the direction orthogonal to the array direction of the line image sensors is scaled. Scanning speed control means for controlling the image data, thinning means for thinning out image data of an arbitrary pixel row in the line image sensor array direction in the image information read by the line image sensor, and read image information by the line image sensor. The scanning speed control means slows down the scanning speed of the line image sensor and magnifies image data by the thinning means as necessary during enlargement processing of the original image. After that, the image data is complemented and enlarged by the complementing means according to the scaling ratio. It is characterized in.

Further, for example, image processing means for performing predetermined image processing on the read image data, and image processing by the image processing means for the read image according to the content of image processing and the scaling factor for the read image data. A selecting means is provided for selecting whether to perform the image data thinning-out by the thinning-out means or after the image data is thinned-out by the complementing means according to the scaling factor. Then, for example, when it is necessary to perform edge processing on the read image, the selecting means performs complementary enlargement of the image data by the complementing means without performing thinning processing by the thinning means, and according to the scaling ratio for the read image data. It is selected to perform image processing by the image processing means.

[0009]

With the above construction, it is possible to obtain a good magnified image regardless of the magnification of the image or the image processing executed. Further, by selectively executing the mechanical scaling processing by changing the scan speed and the electrical complement processing according to the content of the image processing to be processed, the optimal scaling processing according to the processing can be performed. Further, it is possible to obtain a good processing result even if the image processing is edge processing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the drawings. [First Embodiment] FIG. 1 is an external perspective view of a digital full-color copying machine according to the first embodiment of the present invention.

The upper part of FIG. 1 reads a document image and outputs a digital full-color image data to a color image scanner section 1 (hereinafter abbreviated as a scanner section), and various image processing of digital color image data built in the scanner section 1. And a controller unit 2 having a processing function such as an interface with an external device. The lower part of FIG. 1 is a printer unit 3 for recording a color digital image signal output from the controller unit 2 on recording paper. These two parts are configured to be separable, and can also be installed at distant places by extending a connection cable connecting the two parts.

FIG. 2 is a side sectional view showing the internal structure of the digital color copying machine shown in FIG. First, an original image set on an original platen glass by an optical system including an exposure lamp 14, a lens 15, and a CCD image sensor 16 capable of reading a full-color line image,
The projected image by the projector, the sheet original image conveyed by the feeding mechanism 12 one by one, or the like is read.

Next, the scanner unit 1 and the controller unit 2 perform various necessary image processings, and the printer unit 3 records them on recording paper. The recording paper in the printer unit 3 is a cut paper of a small standard size (standard size of A4 to A3 in this embodiment) or a large size (A2 in this embodiment) fed from the paper feed cassette 20. Any of the roll paper fed from the roll paper 29 for recording is selected (up to A1). As for paper feeding, in addition to the automatic paper feeding from the inside of the above-mentioned apparatus, 1
By inserting the recording paper sheet by sheet along the paper feed unit cover 21, it is possible to feed paper from the outside of the apparatus (manual paper feed).

Paper feeding in the printer unit 3 is performed as follows. That is, the pickup roller 24 is a roller for feeding cut sheets one by one from the sheet feeding cassette 20, and the cut sheets are picked up by the pickup roller 24 and conveyed to the cut sheet feeding roller 25.
Further, the cut sheet feeding roller 25 is used to feed the first roller 26.
Be transported to. On the other hand, the roll paper 29 is sent out by the roll paper feed roller 30, cut into a standard length by the cutter 31, and conveyed to the paper feed first roller 26. Similarly, when the recording paper is supplied manually from the outside, the manually supplied recording paper inserted and supplied from the manual insertion port 22 is conveyed to the first paper feed roller 26 by the manual insertion roller 32.

Pickup roller 24, cut sheet feed roller 25, roll paper feed roller 30, first paper feed roller 2
6, the manual feed roller 32 is a paper feed motor (not shown) (for example,
It is driven by a DC servo motor), and on / off control can be performed at any time by an electromagnetic clutch attached to each roller. When the printing operation is instructed by the controller unit 2, the recording sheet selected and fed by any of the above-described sheet feeding paths is conveyed to the first feeding roller 26.
In order to remove the skew of the recording paper, the paper feed first roller 26 is turned on after a predetermined amount of paper loop is formed to turn on the paper feed second roller 2.
The recording paper is conveyed to 7.

Paper feed first roller 26 and paper feed second roller 27
In the interval, in order to perform an accurate paper feeding operation between the paper feeding roller 28 and the second paper feeding roller 27, the recording paper is slackened by a predetermined amount to form a buffer. The buffer amount detection sensor 33 is a sensor for detecting the buffer amount. By constantly making the buffer during paper conveyance, it is possible to reduce the load on the paper feed roller 28 and the second paper feed second roller 27, especially when conveying large-format recording paper, and it is possible to perform accurate paper feed operation. become.

When printing with the recording head 37,
A scanning carriage 34, on which a recording head 37 and the like are mounted, reciprocally scans a carriage rail 36 by a scanning motor 35. At this time, the paper feed motor controls the buffer system such that the drive system is always kept at a predetermined buffer amount while the buffer amount detection sensor 33 detects the drive system. The printed recording paper is ejected to the paper ejection tray 23 to complete the printing operation.

FIG. 3 is a diagram showing the structure around the scanning carriage 34 according to the first embodiment. In FIG. 3, a paper feed motor 40 is a drive source for intermittently feeding the recording paper, and drives the paper feed second roller 27 via the paper feed roller 28 and the paper feed second roller clutch 43. Scanning motor 35
Is a drive source for scanning the scanning carriage 34 in the directions of arrows A and B via the scanning belt 42.

In this embodiment, pulse motors are used as the paper feed motor 40 and the scanning motor 35 because accurate paper feed control is required. When the recording paper reaches the second paper feed roller 27, the second paper feed roller clutch 43 and the paper feed motor 4
0 is turned on and the recording paper is fed to the paper feed roller 28 to the platen 3
9 is conveyed. The recording paper is detected by a paper detection sensor 44 provided on the platen 39, and the sensor information is used for position control and jam control.

When the recording paper reaches the paper feed roller 28,
The second paper feed roller clutch 43 and the paper feed motor 40 are turned off, and a suction motor (not shown) from inside the platen 39 performs a suction operation to bring the recording paper into close contact with the platen 39. Then, the scanning carriage 34 is moved to the position of the home position sensor 41 prior to the image recording operation on the recording paper. Next, forward scanning is performed in the direction of arrow A, and cyan C, magenta M, yellow Y, and black K inks are ejected from the recording head 37 from a predetermined position to perform image recording.

In this embodiment, the ink jet nozzle of the above-mentioned system is used as the recording head 37, and
Fourty-six nozzles assembled in Y, M, C, and K are used. Then, when the image recording for a predetermined length is completed, the scanning carriage 34 is stopped, reverse scanning in the direction of arrow B is started, and the scanning carriage 34 is returned to the position of the home position sensor 41. During this backward scan, the paper feed roller 40 is driven by the paper feed motor 40 to feed the paper by the length recorded by the recording head 37 in the direction of arrow C.

When the scanning carriage 34 is stopped at the home position detected by the photo sensor 41, in order to prevent unevenness at the start of ejection, which is caused by a change in the viscosity of the ink remaining in the nozzles of the recording head 37, etc. Paper time,
Processing such as pressurizing operation on the recording head 37 and idle ink ejecting operation is performed according to pre-programmed conditions such as device internal temperature and ejection time.

By repeating the operation described above, it is possible to record an image on the entire surface of the recording paper. Next, the operation of the scanner unit 1 will be described. FIG. 4 is a diagram showing the internal mechanism of the scanner unit 1 according to the first embodiment. The CCD unit 18 is a unit including the CCD 16 and the lens 15. The CCD unit 18 has a pulley 51 to which the drive shaft of the main scanning motor 50 is fixed, which is fixed on the end of the rail 54, and the other end of the rail 54. It is fixed to a wire 53 suspended between pulleys 52 attached to the section, and scans on a rail 54 according to the rotation of the main scanning motor 50.
Read in the main scanning direction.

Light-shielding plate 55, home position sensor 56
Is used for position control when moving the CCD unit 18 to the home position for main scanning in the correction area 68 in the figure. The rail 54 further rides on rails 65 and 69 arranged at both ends of the reading area of the scanner unit 1, and has a sub-scanning motor 60 and pulleys 67, 68, 71 and 7.
Scanning is performed in the sub-scanning direction by a drive system in the sub-scanning direction, which is composed of 6, shafts 72, 73 and wires 66, 70. That is,
A pulley 68 and a pulley 76 fixed to a rotary drive shaft 72 of a sub-scanning motor 60 arranged at one end (upper end in FIG. 4) of the reading area of the scanner unit 1.
And a wire 70 and a wire 66 suspended between a pulley 71 and a pulley 67 that are respectively fixed to a rotary shaft 73 that is rotatably fixed to the other end (the lower end in FIG. 4).
Both ends of the rail 54 are fixed to the sub-scanning motor 60.
The rails 69 and 65 are scanned in accordance with the rotation of, and movement in the sub-scanning direction is performed.

Light-shielding plate 57, home position sensor 5
Reference numerals 8 and 59 are used for position control when moving the rail 54 to the home position of each sub-scan in the book mode for reading a document such as a book placed on the platen glass 17. FIG. 5 is a diagram for explaining the reading operation in the book mode and the sheet mode according to the first embodiment. In the first embodiment, in the book mode, the CCD unit 18 is moved to the illustrated book mode home position (indicated by the book mode HP in the drawing) in the correction area 68 in FIG. The reading operation of the entire surface of the original placed on the glass 17 is started.

In the correction area 68, prior to scanning the original,
Parameters required for processing such as shading correction, black level correction, and color correction are set. After that, the main scanning motor 50 starts scanning in the main scanning direction, which is the direction of the arrow shown. After the reading operation of the area indicated by is finished, the main scanning motor 50 is rotated in the reverse direction and the sub scanning motor 60 is driven to move the correction area 68 of the area in the sub scanning direction. Subsequently, as in the main scanning of the area, shading correction, black level correction, and color correction processing are performed as necessary, and the reading operation of the area is performed.

By repeating the above-mentioned scanning, the reading operation of the entire area of (1) is performed, and after the reading operation of the area of (3) is completed, the CCD unit 18 is returned to the book mode home position again. In the actual reading operation, since the original platen glass 17 is configured to read a maximum A2 size original, it is necessary to actually scan a larger number of times, but in this description, the operation will be understood. It is simplified to make it easier.

Even in the seat mode, the basic operation is the same as the reading operation in the book mode described above, but the home position is different in both reading modes, for example. The CCD unit 18 is moved to the illustrated seat mode home position (seat mode HP). Then, scanning of the CCD unit 18 in the main scanning direction is started by reciprocating the area of the CCD unit 18 in the direction of the arrow shown by the main scanning motor 50. At this time, at the same time, a sheet feeding motor (not shown) is intermittently operated to sequentially read the sheet original, and the entire surface of the sheet original is read.

At this time, the shading correction, the black level correction, the color correction and the like are performed in the correction area 68 prior to the scanning of the original, and then the CCD unit 18 is moved in the direction of the arrow shown in the drawing to the main scanning motor 50. Then, the scanning is started in the main scanning direction. When the forward scanning operation indicated by the arrow in the area is completed, the main scanning motor 50 is rotated in the reverse direction, the sheet feeding motor is driven during the scanning of the backward scanning, and the sheet original is moved by a predetermined amount in the sub scanning direction. Subsequently, the same operation is repeated to read the entire surface of the sheet original.

The area that can be read by the CCD unit 18 extends over the front surface of the document table 17 shown in FIG. 4, and is not limited by the size of recording paper to be printed out.
This is because the digital color copying machine of this embodiment has a variable magnification function for enlargement and reduction. That is, since the area that can be recorded by the recording head 37 is fixed at 256 bits at a time as described above, when performing a reduction operation of 50%, for example, image information of at least twice as many 512-bit areas is required. This is because Therefore, the scanner unit 1
It has a built-in function to read and output image information of an arbitrary image area by one main scanning reading.

FIG. 6 is a block diagram showing the electrical construction of the digital color copying machine of the first embodiment. In the figure,
The control unit 102 is a control circuit mainly for controlling the scanner unit 1, the control unit 111 is mainly for controlling the controller unit 2, and the control unit 121 is mainly for controlling the printer unit 3. The control circuit is a microcomputer, a program ROM, a data memory, It employs a so-called master-slave control format in which a communication circuit is built in, connected to each other through a signal line, and the control units 102 and 121 operate according to an instruction from the control unit 111.

When the apparatus of this embodiment operates as a color copying machine, the control section 111 performs various operations according to input instructions from the operation section 10 and digitizer 114. Further, the control unit 111 also controls the image processing unit 107 that performs various types of processing related to the image, and the binarization processing unit 108. The control unit 102 controls the drive of mechanical parts such as the motor control shown in FIG. 4 of the scanner unit 1 described above, for example.
05, the exposure control unit 103 that controls the exposure of the lamp that irradiates the read document is also controlled. The control unit 102 also controls the analog signal processing unit 100 and the input image processing unit 101 that perform various types of processing related to images.

The control unit 121 controls the printer unit 3 described above.
2 is a synchronous delay processing memory that absorbs the time variation of the mechanical operation of the mechanical drive unit 122 and the printer unit 3 that controls the drive of the mechanical unit and the like shown in FIG. 2 and corrects the delay due to the arrangement of the recording heads 117 to 120 on the mechanism. The control of 115 is performed. Next, the image processing of the present embodiment having the above configuration will be described with reference to FIG.
Refer also to the explanation.

The read color image information formed on the CCD 16 is converted into a corresponding analog electric signal by the CCD 16. The converted color image information is serially processed in the order of red, green, and blue and input to the analog signal processing unit 100. In the analog signal processing unit 100,
After performing predetermined image processing such as sample & hold, dark level correction, and dynamic range control for each color of red, blue, and green, analog-digital conversion (hereinafter abbreviated as "A / D conversion") is performed, It is converted into a serial multi-valued (8-bit length for each color in this embodiment) digital image signal and output to the input image processing unit 101.

In the input image processing unit 101, correction processing required in a reading system such as known shading correction and color correction is performed with the serial multi-valued digital image signal as it is. Then, after performing necessary correction processing, the corrected image signal is output to the image processing unit 107 of the controller unit 2. The image processing unit 107 of the controller unit 2 performs known smoothing processing, edge enhancement processing, black character processing, black extraction processing, masking processing for color correction of recording ink used by the recording heads 117 to 120, and the like. Further, the image processing unit 107 of the present embodiment also includes a thinning circuit for image data and a circuit for enlarging an image in which image data obtained by complementing adjacent image data is enlarged. Also do. Then, the serial multi-valued image data for which various image processes have been completed is output to the binarization processing unit 108.

The binarization processing unit 108 is an image processing unit 107.
This is a circuit for binarizing the serial multi-valued image data, and performs pseudo halftone processing. Here, the serial multi-valued digital image signal is converted into 4-color binary parallel image data. The synchronous delay memory 115 of the printer unit 3 is a circuit that also absorbs the time variation of the mechanical operation of the printer unit 3 and generates the timing necessary for driving the recording heads 117 to 120. Binary parallel image data is delayed for a predetermined time.

The head driver 116 is an analog drive circuit for driving the recording heads 117 to 120 from the synchronous delay memory 115, and the recording heads 117 to 120.
It internally generates a signal that can directly drive. Recording head 1
Reference numerals 17 to 120 respectively discharge cyan (C), magenta (M), yellow (Y), and black (BK) inks to record an image on the recording paper.

As described above, the original image read by the scanner unit can be copied and output from the printer unit 3. The above-described processing is the normal read and copy printing processing including the controller unit 2, but the apparatus of the present embodiment can also perform the scaling processing as described above. The scaling process of this embodiment will be described below. In the following description, as an example of the scaling process, the enlargement process will be described with reference to FIG. 7.

FIG. 7 shows in detail the configuration of the scaling and edge processing section of the image processing section 107 shown in FIG. Here, in order to simplify the description, a case will be described where the magnification is increased to 200% in both the main scanning direction and the sub scanning direction. In FIG. 7, reference numeral 71 is a sub-scanning thinning circuit for thinning out pixel data in the sub-scanning direction, 72 is an edge processing circuit for performing various edge processing such as edge enhancement processing, black character processing, contour processing on the input image, and 73 is a main scanning direction. A main-scanning supplemental enlargement circuit for supplementing and enlarging pixel data, 74 a sub-scanning supplementary enlarging circuit for supplementing and enlarging pixels in the sub-scanning direction, and 75 and 76 sub-scanning thinning circuits 71 under the control of a CPU (not shown) of the control unit 111. And a selector for selecting whether or not to bypass the sub-scanning complementary enlargement circuit 74.

In the above configuration, the control section 111 controls the selectors 75 and 76 to control whether or not to bypass the sub-scanning decimation circuit 71 and the sub-scanning supplementary expansion circuit 74. Now, paying attention to the point that will be described in detail later, when the enlargement ratio is 150% or less, the selector 7
5, 76 are controlled to bypass the sub-scanning decimation circuit 71 and the sub-scanning supplementary expansion circuit 74.

First, the main scanning direction (arrangement direction of CCD 16)
However, since the number of nozzles of the recording heads 117 to 120 of the printer unit 3 in this embodiment is 256,
If the magnification is 200%, the number of pixels read by the CCD 16 is only 128 in the sub-scanning direction in one scan, and 128 pixels are read. The image data of 128 pixels in the sub-scanning direction is set to 1 as shown in FIG.
The pixel data is shifted every other pixel, and is expanded so as to be pseudo pixel data for 256 pixels. Then, for the portions 1 ', 2', 3 '... 128' where the image data does not exist, the image data is generated while complementing the effective pixel data before and after that so that the data is smoothly connected. A publicly known method can be adopted for this complementary enlargement processing.

Such processing is performed for all 128 pixels to obtain image data for 256 pixels. This processing is independently performed for each of R, G, and B colors. As described above, the length recorded for one reading in the sub-scanning direction is doubled, that is, increased to 200%. The main-scanning complementing expansion circuit 73 in FIG. 7 performs this expansion-complementing process. The enlargement complementing process in the main scanning complementation enlarging circuit 74 can be a known enlargement complementing process.

Next, the enlarging method in the sub-scanning direction will be described. In the present embodiment, the enlargement in the sub-scanning direction is not performed electrically as in the conventional case, but if the enlargement processing is performed up to an enlargement ratio of 149%, the enlargement is performed mechanically as will be described in detail later, and 150% or more. In the case of the enlargement ratio of, the control unit 111 controls so as to perform a pseudo equal-magnification process described in detail later.

When the enlargement processing in the sub-scanning direction is executed by using mechanical means, the moving speed of the CCD unit 16 in the sub-scanning direction is slowed according to the magnification, and C
The reading frequency of the image data from the CD unit 16 may be read at the same timing as the reading timing in the equal-magnification processing. For example, in the case of enlarging to 200%, if the moving speed of the CCD unit 16 in the sub-scanning direction is halved at the same magnification, and the image reading cycle is the same as that at the same magnification, the image to be read is read. The amount of data is half the amount of movement, and the same amount of data is obtained, and the recorded image is 200
% Will be expanded (this process is called "mechanical expansion" hereafter)
Abbreviated. ).

However, the image thus obtained is
The pixel density of the CCD 16 is constant (400 dp in this embodiment).
Despite i), since the reading density of the original is doubled, the read image has an image with loss of sharpness and smoothing processing. For example, even if it is attempted to apply edge enhancement to such image data to make the edge portion sharp and output a sharp image, it is difficult to detect the edge portion itself, and the effect of the edge enhancement processing is not very obtained. (This also applies to the image data in the main scanning direction after the enlargement process).

In order to effectively apply the edge enhancement to the enlarged image thus obtained, the edge enhancement processing is applied to the image data before the enlargement processing in the main scanning direction, and then the enlargement is performed. It suffices to execute the processing. That is, as shown in FIG. 7, in the sub-scanning direction, the image data read at a predetermined enlargement ratio is used as the sub-scanning thinning circuit 71.
By thinning out with, it is possible to obtain a pseudo same-size image. Then, after the edge component in the image is generated, the edge processing circuit 72 applies the edge enhancement processing, and thereafter, the sub-scanning complementing circuit 74 enlarges and complements the image electrically so as to have a predetermined enlargement ratio as in the main scanning direction. The same effect as that in the main scanning direction can be obtained by executing the process (hereinafter, this process is abbreviated as “pseudo equal-magnification process”).

FIG. 9 shows the processing of the image data when the read image data is enlarged to 200% and the complementary processing is performed. In the present embodiment, when a read image as shown at 91 in FIG. 9 is obtained, first the sub-scanning thinning circuit 71 shown in FIG. 7 executes the thinning processing in the sub-scanning direction, and at 92 in FIG. The sub-scanning thinned image shown is obtained. The edge processing circuit 72 performs edge enhancement processing on the thinned data, and the sub-scanning complementary magnification circuit 74 executes complementary magnification processing on the edge enhancement processing. Image data 94 is finally enlarged and complemented by 200% in both main scanning and sub-scanning.

As described above, in the present embodiment, when the enlarging process is performed, the mechanically enlarging and reading image data is once electrically thinned and the edge process is performed, and then the electrically enlarging process is performed. As a result, sufficient edge processing can be applied. However, when such a method is adopted, since the electrical enlargement processing is performed in the sub-scanning direction as in the main scanning direction, when the original is a halftone image or is composed of thin lines, the CCD unit 16 is used. In addition to the interference fringes (hereinafter referred to as “moiré”) generated by the interference with the reading aperture of each cell, the possibility of moiré is increased by this electrical thinning process.
This is because the edge component is likely to be emphasized before and after the thinned pixels. FIG. 10 illustrates the moire generated by this electrical enlargement process.

FIG. 10 shows 110% of the read image data.
This shows the case of expanding and complementing. 1001 is an original image read, and the number of pixels is set to 10 here to simplify the description. On the other hand, the result of 110% enlargement processing is 1002, and the number of pixels is increased to 11 pixels. In this embodiment, as the method of complementation, straight line complementation between adjacent pixels is performed, so the density gradient between the original pixels 1 and 2 is first obtained. Then, complementary data is obtained from the density gradient according to the enlargement ratio. In this case, since the enlargement is 110%, the density data of the portion corresponding to 1.9 between the pixels 1 and 2 is output as the second pixel as the complementary data (the input pixel is directly output to the first pixel). ). Similarly, the following 2 to 10 pixels are complemented to obtain an output for 11 pixels.

Next, the case where moire occurs due to 1003 and 1004 will be described. 1003 is an input pixel, which is a model similar to that when a halftone image or the like is read. In this example, the densities are alternately changed like 0 and 100 for each pixel, and the output is 1004 when this is enlarged and complemented to 110% by the above method. Looking at this density distribution, it can be seen that the entire contrast appears as low-frequency unevenness as shown by 1005, and interference unevenness is caused by the beat between the density cycle of the input image and the expansion complement cycle.

This complementary enlargement unevenness may occur because the same enlargement complementary method is used in the main scanning direction as well, but it is usually designed so as not to be extremely caused by the MTF setting and smoothing processing of the optical system. That is also the case in the present embodiment. However, in the present embodiment, as described above, in order to sufficiently apply the edge processing in the sub-scanning direction at the time of enlargement, pixel data is thinned out at the time of enlargement so that a pseudo equal-magnification image is formed, and the edge component in the image data is As a result, the degree of occurrence of moire becomes higher than that in the main scanning direction.

However, even with image data that has undergone such pseudo equal-magnification processing, if the enlargement ratio becomes large, the amount of thinning-out and complementation of pixel data will increase, and the frequency of interference unevenness itself will increase. For this reason, the unevenness is less noticeable, and the deterioration of the output image is less likely to occur. In the experimentally obtained data, the problem of moiré due to the pseudo equal-magnification processing is up to about 101% to 110%, and at a magnification higher than this, the moiré difference between the main scanning direction and the sub-scanning direction cannot be determined. descend. Further, if the enlargement ratio is about this level, the edge component remains in the read image sufficiently even in the mechanical enlargement, regardless of the pseudo equal-magnification process, and the edge process can be performed to the same extent as in the case of equal magnification.

As described above, in this embodiment, the pseudo-magnification processing described above is not performed up to a magnification of 150%, and the pseudo-magnification processing described above is applied when the magnification is 150% or more. The automatic selection of 111 suppresses the occurrence of moire due to the pseudo equal-magnification processing, and in the case of a high enlargement ratio, the pseudo equal-magnification processing provides sufficient edge processing. Moire is suppressed even in high-magnification images, and sufficient edge processing is applied. In the above description, the edge enhancement processing is mainly described as an example, but it goes without saying that good results can be obtained for the overall processing of extracting the contour portion in the image such as black character processing (performing contour detection of a character). is there.

[Second Embodiment] In the first embodiment described above, the configuration in which the mechanical enlargement and the electric enlargement by the pseudo equal magnification process are switched according to the enlargement ratio has been described, but the present invention is not limited to this. However, for example, if the user selects edge enhancement or black character processing, pseudo-magnification processing is selected, and if smoothing processing is selected, mechanical enlargement is selected. It may be selected, and a good image can be obtained as in the first embodiment. Further, it may be switched depending on the type of document to be read. By controlling in this way, the processing method suitable for each processed image can be selected, and the configuration and the processing amount can be optimized.

[Third Embodiment] In the above description, when a document image or the like is read, the CCD sensor capable of reading a predetermined number of pixels is scanned and scanned in the main scanning direction and the sub scanning direction. However, the present invention is not limited to the above example, and the CCD sensor may be used as a line sensor so that the entire surface of the original can be read by one movement in the sub-scanning direction. The third embodiment according to the present invention having the above-described structure will be described below.

FIG. 11 is a view for explaining the third embodiment according to the present invention, and is an outline drawing of an image reading apparatus using a line sensor having a length equal to or longer than one side of a document to be read. Is shown. Third as shown in FIG.
The embodiment is of a type in which the image of the entire surface of the original can be read by one sub-scanning (note that the length of one side of the original to be read by arranging a plurality of short line sensors in the main scanning direction is equal to or more than that). It may be a line sensor having a length of. Even in the image reading apparatus having such a configuration, the present invention can be applied without any change, and effective effects can be obtained.

As described above, according to each of the above-described embodiments, the image reading apparatus is provided with two types of methods, that is, mechanical enlargement as enlargement means in the sub-scanning direction and electrically complementary enlargement after pseudo equal magnification processing. However, a high-quality enlarged image can be obtained by appropriately switching between these two types according to the type of original and the image reading mode. The present invention may be applied to a system including a plurality of devices or an apparatus including a single device.

It goes without saying that the present invention can also be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0059]

As described above, according to the present invention, the image reading apparatus is provided with two types of means, that is, mechanical enlargement as enlargement means in the sub-scanning direction, and electrically complementary enlargement after pseudo equal magnification processing. By appropriately switching between these two types according to the type of document and the image reading mode, there is an effect that a high quality enlarged image can be obtained.

[Brief description of drawings]

FIG. 1 is an external perspective view of a digital full-color copying machine according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing the internal structure of the digital color copying machine of FIG.

FIG. 3 is a diagram showing a configuration around a scanning carriage according to the present embodiment.

FIG. 4 is a diagram showing a mechanism inside a scanner unit according to the present embodiment.

FIG. 5 is a diagram illustrating a reading operation in a book mode and a sheet mode according to the present embodiment.

FIG. 6 is a block diagram showing the electrical configuration of the digital color copying machine of this embodiment.

7 is a diagram showing a detailed configuration of a scaling and edge processing unit of the image processing unit shown in FIG.

FIG. 8 is a diagram for explaining a method of expanding pixels in the sub-scanning direction in the scaling processing according to the present embodiment.

FIG. 9 shows the read image data of 200 in this embodiment.
It is a figure which shows the process of the image data at the time of performing the expansion and the complement process to%.

FIG. 10 shows the read image data in this embodiment as 1
It is a figure for demonstrating the process which carries out expansion complement to 10%.

FIG. 11 is a diagram illustrating a third embodiment according to the present invention.

[Explanation of symbols]

 1 Color Image Scanner Section (Scanner Section) 2 Controller Section 3 Printer Section 10 Operating Section 12 Feeding Mechanism 14 Exposure Lamp 15 Lens 16 CCD Image Sensor 17 Platen Glass 18 CCD Unit 20 Paper Feed Cassette 22 Hand Feed Port 23 Paper Ejection Tray 24 Pickup Roller 25 Cut paper feed roller 26 Paper feed first roller 27 Paper feed second roller 28 Paper feed roller 29 Roll paper 30 Roll paper feed roller 31 Cutter 32 Manual feed roller 33 Buffer amount detection sensor 34 Scan carriage 35 Scan motor 36 Carriage rail 37 Recording head 39 Platen 40 Paper feed motor 41 Home position sensor 42 Scanning belt 43 Paper feed second roller clutch 44 Paper detection sensor 50 Main scanning motor 51, 52, 67, 68, 71, 76 RE 53, 66, 70 Wire 54, 65, 69 Rail 55, 57 Light-shielding plate 56, 58, 59 Home position sensor 60 Sub-scanning motor 68 Correction area 72, 73 Axis 100 Analog signal processing unit 101 Input image processing unit 102, 111 , 121 control unit 103 exposure control unit 105, 122 mechanical drive unit 107 image processing unit 108 binarization processing unit 114 digitizer 115 synchronous delay processing memory 116 head driver 117 to 120 recording head

Claims (10)

[Claims] 1. An image processing apparatus which scans a line image sensor to read an original image and performs a predetermined scaling process on the read image information, wherein a scanning speed in a direction orthogonal to an array direction of the line image sensors is set. Scan speed control means for controlling according to the scaling factor, thinning means for thinning out image data of an arbitrary pixel row in the line image sensor array direction in the read image information by the line image sensor, and read image by the line image sensor Complementary enlarging means for complementing and enlarging any pixel row in the information, the scan speed control means slows down the scan speed of the line image sensor at the time of enlarging processing of the original image, and the thinning means image data by the thinning means as necessary. After thinning out, the image data is Image reading apparatus, characterized by complete expansion. 2. An image processing means for performing a predetermined image processing on the read image data, and an image processing by the image processing means for the read image according to the content of the image processing on the read image data and the scaling factor. 2. The image processing apparatus according to claim 1, further comprising selection means for selecting whether to thin and complement the image data by the thinning means and then to complement and enlarge the image data by the complementing means according to a scaling factor. 3. The thinning-out means electrically thins out image data of an arbitrary pixel row with the pixel row in the array direction of the line image sensor as one unit.
Alternatively, the image processing apparatus according to claim 2. 4. The document image reading interval from the line image sensor is not changed even when the scan speed of the line image sensor is controlled by the scan speed control means. The image processing device according to any one of 1. 5. The selecting means performs complementary expansion of image data by the complementing means without performing thinning processing by the thinning means when it is necessary to perform edge processing of the read image, and transforms the read image data. The image processing apparatus according to claim 3, wherein the image processing unit is selected to perform image processing according to the magnification. 6. An image processing method in an image processing apparatus for scanning a line image sensor to read a document image and subjecting the read image information to a predetermined scaling process, wherein the line image sensor array is arranged at the time of magnifying the document image. The scanning speed in the direction orthogonal to the direction is controlled so as to be slowed according to the scaling ratio, and an image of an arbitrary pixel row in the line image sensor array direction in the image information read by the line image sensor as necessary. An image reading processing method comprising thinning out data, and then complementarily enlarging an arbitrary pixel column in image information read by the line image sensor. 7. An image processing means for performing a predetermined image processing on the read image data, and a predetermined image processing for the read image according to the content of the image processing on the read image data and a scaling factor, or 7. The image processing method according to claim 6, wherein after the read image data is thinned out, it is selectively executed whether to complement and enlarge the image data according to the scaling factor. 8. The thinning-out process electrically thins out image data of an arbitrary pixel column with the pixel column in the array direction of the line image sensor as one unit.
Alternatively, the image processing method according to claim 7. 9. The document image reading interval from the line image sensor is not changed even when the scan speed of the line image sensor is controlled. Image processing method. 10. When it is necessary to perform edge processing on the read image, the image data is complemented and enlarged without performing the thinning-out process, and predetermined image processing is performed according to a scaling ratio for the read image data. The image processing method according to claim 8, wherein the image processing method is selected.