JP3468966B2 - Image processing device - 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 processing apparatus, and more particularly, it is suitable for an image reading unit for reading an image and an image recording unit for recording the image even when there is a difference in linear density or gradation. The present invention relates to an image processing apparatus capable of performing recording while making the recording characteristics of an image recording unit to be exhibited.

[0002]

2. Description of the Related Art In an image processing apparatus for inputting and outputting an image such as a digital copy, a facsimile machine and an optical file, an image reading section for reading an image of an original and an image recording for recording the image on a recording paper are generally used. The linear densities of the image forming unit and the image forming unit are set to be the same, but in recent years, there has been a demand for improvement in recording quality, and image processing apparatuses using high-performance image recording units have appeared.

For example, in a facsimile machine, a facsimile machine having a plotter having a linear density higher than that of a scanner, which is an image reading unit, has appeared, and in such a facsimile machine, the linear density of the scanner is used. The image data having the linear density set by is transmitted and received, the received image data is enlarged immediately before being transferred to the plotter, and the image data enlarged by the plotter is recorded and output.

An example of such a conventional facsimile apparatus is disclosed in Japanese Patent Application Laid-Open No. 62-252273. This facsimile apparatus uses an original reading section and a linear density of the original reading section. Also has an image recording section having a large linear density and an image information expanding section for previously enlarging the input image information to the image recording section. It is characterized in that it is enlarged by a reciprocal number times the linear density ratio between the reading section and the image recording section.

Therefore, according to this facsimile apparatus, the image read by the document reading unit can be enlarged and recorded according to the linear density of the image recording unit, or can be reduced and recorded.

[0006]

However, in such a conventional image processing apparatus such as a facsimile apparatus, the image is simply enlarged in accordance with the linear density of the image recording section. There has been a problem that the recording characteristics of the recording portion cannot be fully exhibited and the image quality is deteriorated.

Therefore, according to the present invention, the image data is expanded in accordance with the linear density of the image recording means and the gradation processing is performed in accordance with the gradation degree of the image recording means, so that the recording characteristics of the image recording means are sufficiently improved. It is an object of the present invention to provide an inexpensive image processing apparatus that can be effectively used to record an image read by a low-resolution image reading unit with high quality.

Further , according to the present invention, an edge of an image is detected, and edge enhancement processing is applied to an edge portion such as a character or a thin line, so that an image such as a character or a thin line read by a low-resolution image reading means is displayed. It is also an object of the present invention to provide an inexpensive image processing apparatus capable of performing appropriate reproduction to sufficiently perform the recording characteristics of the high-resolution image recording unit for recording.

Further , according to the present invention, an edge of an image is detected, edge enhancement processing is performed on an edge portion such as a character or thin line, and smoothing processing is performed on a portion other than the edge, and then gradation processing is performed. It properly reproduces images such as characters and fine lines read by low-resolution image reading means, and also smoothly reproduces patterns and photographic images, and makes full use of the recording characteristics of high-resolution image recording means for recording. It is an object of the present invention to provide an inexpensive image processing device that can be used.

Another object of the present invention is to provide an image processing apparatus capable of further improving the reproducibility of characters and fine lines by performing edge enhancement processing according to the edge strength.

[0011]

An image processing apparatus according to the present invention comprises an image reading means for reading an image of an original at a predetermined linear density and outputting it as image data, and a predetermined gradation degree and the image reading means. Recording means for recording and outputting an image on a recording paper at a linear density higher than that of the recording medium, enlargement processing means for enlarging the image data read by the image reading means in accordance with the linear density of the recording means, and the enlargement. Gradation processing means for converting the expanded image data of the processing means according to the gradation degree of the recording means, and recording the image data converted by the gradation processing means by the recording means. By outputting, the above-mentioned object is achieved.

As the image reading means, an inexpensive one having a relatively low linear density can be used, and the reading method is not limited at all. The recording unit records the image with a higher linear density than that of the image reading unit and with a predetermined gradation.

The enlargement processing means makes the image data read by the image reading means correspond to the linear density of the recording means by a predetermined enlargement method, that is, the linear density of the recording means / the linear density of the image reading means. Enlarge image data by ratio. The enlarging method of the enlarging processing means is not limited.

The gradation processing means converts the number of gradations of the image data enlarged by the enlargement processing means according to the gradation degree of the recording means. As the gradation method, for example, a pseudo halftone processing method such as a multi-value error diffusion processing method or a multi-value dither processing method can be used, but the gradation method is not limited.

According to the above construction, the image data read by the low-resolution image reading means can be expanded and gradation processed according to the high-resolution recording means, and an inexpensive image reading means can be used. Then, it is possible to record a high-quality image similar to the case where the image is read by the high-resolution reading unit and is recorded by the high-resolution recording unit.

Further , the image processing apparatus of the present invention comprises an image reading means for reading an image of a document at a predetermined linear density and outputting it as image data, a predetermined gradation degree, and a linear density of the image reading means. A recording means for recording and outputting an image on a recording paper with a high linear density; an enlarging processing means for enlarging the image data read by the image reading means according to the linear density of the recording means; and enlarging the enlarging processing means. Edge determining means for determining the edge of the image of the image data,
Edge enhancement processing means for performing edge enhancement processing on the enlarged image data of the enlargement processing means, and gradation for converting the number of gradations of the enlarged image data of the expansion processing means according to the gradation degree of the recording means. A processing means; and a selection means for selecting the edge-enhanced image data of the edge enhancement processing means and the image data converted by the gradation processing means based on the determination result of the edge determination means. The above-mentioned object is achieved by recording and outputting the image data selected by the selecting means by the recording means.

Here, the edge determination means determines the edge portion of the image such as characters and lines, and the edge determination method is not limited. The edge enhancement processing means enhances the edge portion of the image to be clear, and the edge enhancement method is
Although not limited in any way, for example, it can be performed by multiplying the target pixel and its peripheral pixels by a predetermined edge enhancement coefficient.

According to the above construction, the image data read by the image reading means having a low resolution is enlarged in accordance with the recording means having a high resolution, and the edge portion of the image is subjected to the edge emphasis processing to obtain an image of the image. For the non-edge portion, gradation processing can be performed, and it is possible to improve the reproducibility of characters, thin lines, etc. of an image read by using an inexpensive image reading unit, and record an image of higher quality. it can.

Further , the image processing apparatus of the present invention comprises an image reading means for reading an image of a document at a predetermined linear density and outputting it as image data, a predetermined gradation degree, and a linear density of the image reading means. A recording means for recording and outputting an image on a recording paper with a high linear density; an enlarging processing means for enlarging the image data read by the image reading means according to the linear density of the recording means; and enlarging the enlarging processing means. Edge determining means for determining the edge of the image of the image data,
An edge enhancement processing unit that performs edge enhancement processing on the enlarged image data of the enlargement processing unit, a smoothing processing unit that performs smoothing processing on the enlarged image data of the enlargement processing unit, and a smoothing processing unit. Gradation processing means for converting the number of gradations of the smoothed image data according to the gradation degree of the recording means, and the image data for which edge enhancement processing by the edge enhancement processing means is performed based on the determination result of the edge determination means. And selecting means for selecting the image data converted by the gradation processing means, and the above-mentioned object is achieved by recording and outputting the image data selected by the selecting means by the recording means. .

Here, the smoothing means smoothes the image data smoothly, and the smoothing method can be performed, for example, by multiplying the target pixel and its peripheral pixels by a predetermined smoothing coefficient. Yes, but it is not limited in any way.

According to the above construction, the image data read by the image reading means having a low resolution is enlarged in accordance with the recording means having a high resolution, and the edge portion of the image is subjected to the edge emphasis processing to obtain an image of the image. The non-edge portion can be subjected to gradation processing after smoothing processing, and the reproducibility of characters and fine lines can be improved by using an inexpensive image reading means, and at the same time, images of patterns and photographs can be obtained. It is possible to improve reproducibility. As a result, it is possible to record a higher quality image by using the inexpensive image reading means.

[0022] In the above case, for example, pre-Symbol edge determination means, wherein also determine the intensity of the edge of the image data, the edge enhancement processing means, based on the intensity of the determined the edge of the edge determination means Edge enhancement processing may be performed by changing the degree of edge enhancement.

According to the above arrangement, the edge strength can be determined and the edge enhancement processing can be performed in accordance with the edge strength, so that the reproducibility of characters and thin lines can be reproduced more appropriately. You can

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are attached, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

1 to 8 are diagrams showing an image processing apparatus to which an embodiment of the image processing apparatus of the present invention is applied. FIG. 1 is a circuit block diagram of an image processing apparatus 1 to which an embodiment of the image processing apparatus of the present invention is applied.

In FIG. 1, the image processing apparatus 1 includes a scanner unit 2, a memory unit 3, an enlargement processing unit 4, an edge determination unit 5,
An edge enhancement unit 6, a smoothing processing unit 7, a selector 8, a gradation processing unit 9, a printer unit 10, a controller 11 and the like are provided, and the above units are connected by a bus 12.

The scanner section (image reading means) 2 is composed of, for example, an image scanner using a CCD (Charge Coupled Device) and its peripheral circuits,
Generally, an ADF (Automatic Document Feeder) is provided. A
A plurality of originals are set in the DF, and the ADF feeds the set originals one by one to the original reading unit of the scanner unit 2. The scanner unit 2 scans the document conveyed from the ADF, reads the image of the document at a predetermined resolution (linear density and dot density), and outputs it as black and white multivalued image data. The scanner unit 2 is not limited to an image scanner using a CCD, and may be any unit as long as it reads an image of a document at a predetermined resolution and outputs it as multi-valued black and white image data. Good.

The memory unit 3 is formed of, for example, a RAM or the like, is managed under the control of the controller 11, and is used to temporarily store the image data of each processing stage.

The enlargement processing section (enlargement processing means) 4 operates under the control of the controller 11 and enlarges the image data in accordance with the linear density of the printer section 10. That is, when the linear density of the printer unit 10 is La and the linear density of the scanner unit 2 is Lb, the enlargement processing unit 4 enlarges the image data read by the scanner unit 2 at a ratio R of La ÷ Lb. . For example, the linear density La of the printer unit 10 is now set to 4
00 dpi, the linear density Lb of the scanner unit 2 is set to 200 dpi
If it is i, the enlargement processing unit 4 is La ÷ Lb = 400/2
00 = enlargement processing with a ratio R of 2 times. The enlargement processing unit 4
The image enlarging method is not limited in any way, and a known method can be used. For example, a method of directly interpolating a pixel of interest (a pixel of interest) in the main scanning direction and the sub-scanning direction, or an adjacent method Any method may be used, such as a method of performing interpolation calculation between pixels and interpolating with a calculated pixel value.

The edge determination section (edge determination means) 5 is configured as shown in FIG. 2, and includes a plurality of matrix circuits 21a to 21d, a maximum value detection circuit 22 and a determination circuit 23. The pixel data of the image data read by the scanner unit 2 and temporarily stored in the memory unit 3 is sequentially input to the edge determination unit 5, and this pixel data is set as a target pixel, and the target pixel is set to the matrix circuits 21a to 21a.
At 21d, a filtering process is performed by a weighting filter, that is, a convolution operation of the target pixel and peripheral pixels is performed to extract the edge component of the target pixel data, and the absolute value of the calculated value is output to the maximum value detection circuit 22. That is,
As shown in FIG. 2, each of the matrix circuits 21a to 21d has a different matrix coefficient, and the input target pixel is multiplied by each matrix coefficient, and the absolute value is output to the maximum value detection circuit 22. .

The maximum value detection circuit 22 detects the maximum absolute value input from each of the matrix circuits 21a to 21d, and the detected maximum value is used as an edge amount indicating the size of the edge in the pixel of interest to determine the maximum value. To the edge enhancement unit 6 and the selector 8.
The determination circuit 23 determines whether or not the pixel of interest is an edge by comparing the edge amount input from the maximum value detection circuit 22 with a preset reference value, and
The non-edge determination result is output to the selector 8 described later.

The edge determination section 5 is not limited to the above-described one, but any method capable of appropriately performing the edge amount and edge determination may be used to determine the edge determination and the edge amount. May be performed.

The edge emphasizing section (edge emphasizing means) 6 carries out an emphasizing process by calculating an edge emphasizing coefficient in n × m pixels around the target pixel. That is, the edge emphasizing unit 6 is provided with, for example, a plurality of edge emphasizing matrix coefficients 25a and 25b as shown in FIG. 3, and the edge emphasizing matrix is multiplied based on the edge amount input from the edge determining unit 5. The coefficients 25a and 26b are selected, the input target pixel and peripheral pixels are multiplied by the selected edge enhancement matrix coefficients 25a and 25b, and edge enhancement processing is performed. In FIG. 3, a strong edge enhancement coefficient 26a ((a) of FIG. 3) that strongly enhances an edge and a weak edge enhancement coefficient 26b ((b) of FIG. 3) that weakly enhances an edge.
The case where two types of edge enhancement coefficients, i.e., and, are provided is shown.

A smoothing processing section (smoothing processing means) 7 performs a smoothing process by calculating a smoothing coefficient for n × m pixels around the target pixel. That is, the smoothing processing unit 7, for example,
The smoothing matrix coefficient 27 as shown in FIG. 4 is provided. By using this smoothing matrix coefficient 27, the smoothing process is performed by performing the convolution operation of the pixel of interest and the peripheral pixels sequentially input. To do. As will be described later, the image data smoothed by the smoothing processing unit 7 is gradation processed by the gradation processing unit 9.

The selector (selection means) 8 is based on the judgment result of the edge judgment unit 5 and the image data subjected to the edge emphasis by the edge emphasis unit 6 and the image data subjected to the gradation process by the gradation processing unit 9. , To select the printer unit 10
Alternatively, it is output to the memory unit 3.

The gradation processing section (gradation processing means) 9 has a level that matches the image data enlarged by the enlargement processing section 4 and the image data smoothed by the smoothing processing section 7 to the characteristics of the printer section 10. Convert to a key. That is, the printer unit 10
Normally, it has a gradation reproducibility of 10 to 10 numerical values per pixel, and the gradation processing unit 9 uses the printer unit 10 to process the enlarged image data and the smoothed image data.
The gradation processing is performed according to the characteristics of. The method of gradation processing in the gradation processing unit 9 is not limited,
The number of gradations is reduced by performing pseudo halftone processing by a known method, for example, a multi-value error diffusion method or a multi-value dither method. For example, when performing gradation processing by the multi-valued error diffusion method, the gradation processing unit 9 temporarily quantizes the input multi-valued image data pixel by pixel and inputs the quantized image data as input. In the case where gradation processing is performed on the result of diffusing a binarization error with multi-valued image data into peripheral pixel data based on a predetermined threshold value, and when gradation processing is performed by the multi-value dither method, The level of each pixel of the input multivalued image data is compared with the dither matrix data in which a plurality of predetermined threshold values are set, and the input multivalued image data is subjected to gradation processing based on the comparison result. .

The printer section (recording means) 10 is, for example,
A laser printer or the like is used, and an image is recorded and output on a recording sheet with a predetermined linear density and a predetermined gradation based on the input image data. The linear density of the scanner unit 2 is lower than that of the printer unit 10, that is, the linear density of the printer unit 10 is higher than that of the scanner unit 2.

The controller 11 is a CPU (Central Pr
ocessing Unit), ROM (Read Only Memory) and R
The image processing apparatus 1 is configured by an AM (Random Access Memory) or the like, and controls each unit of the image processing apparatus 1 based on a program in the ROM to execute processing as the image processing apparatus 1. In particular,
The controller 11 enlarges the image data read by the scanner unit 2 by the enlargement processing unit 4, an edge determination process that causes the edge determination unit 5 to perform edge determination, and an edge enhancement unit 6 that determines the edge of the edge portion that has been subjected to edge determination. Edge enhancement processing for enhancing by, smoothing processing for smoothing a portion other than edges (non-edge portion) by the smoothing processing section 7, and reducing the number of gradations of the smoothed image data according to the characteristics of the printer section 10. The gradation process to be performed and the selection process to select the above-mentioned processed image data are executed.

Next, the operation will be described. The image processing apparatus 1
The image data read by the scanner unit 2 at a predetermined linear density is enlarged in accordance with the linear density of the printer unit 10, and then edge determination is performed to perform edge enhancement processing or smoothing processing and the characteristics of the printer unit 10. Is characterized in that gradation processing is performed in accordance with the above, and the printer unit 10 records and outputs.

Firstly, if to be recorded for performing only expansion increasing processing and gradation processing based on the processing illustration of FIG. 5 will be described below.

Under the control of the controller 11, the image processing apparatus 1 displays the image of the document set on the scanner section 2 at a predetermined linear density Lb, for example, 200 dp, as shown in FIG.
The image data read by the scanner unit 2 is transferred to the enlargement processing unit 4 directly or via the memory unit 3 as necessary.

The enlargement processing unit 4 enlarges the image data read by the scanner unit 2 with a ratio R of the linear density La of the printer unit 10 and the linear density Lb of the scanner unit 2. For example, as described above, when the ratio R = La / Lb = 400/200 = 2, the enlargement processing unit 4 doubles the image data read by the scanner unit 2 and the enlarged image data. Is transferred to the gradation processing unit 9 directly or via the memory unit 3. The gradation processing unit 9 performs gradation processing on the transferred image data according to the characteristics of the printer unit 10, and transfers the gradation-processed image data to the printer unit 10. The printer unit 10 records and outputs an image on recording paper based on the image data transferred from the gradation processing unit 9.

As described above, after the image data read by the scanner 2 having a low linear density is enlarged to the linear density of the printer unit 10, the gradation process is performed in accordance with the characteristic (gradation degree) of the printer unit 10. The printer unit 10 can perform recording with the same image quality as when an image is read using the scanner unit 2 having a high linear density, and the inexpensive image processing apparatus 1 using the inexpensive scanner unit 2 can provide high image quality. Images can be recorded.

Next, a case in which the enlargement processing, the gradation processing and the edge enhancement processing according to claim 1 are performed for recording will be described below with reference to the processing explanatory diagram of FIG.

Under the control of the controller 11, the image processing apparatus 1 causes the scanner unit 2 to read the image of the document set on the scanner unit 2 at a predetermined linear density Lb in the same manner as described above.
The image data read by is directly or, if necessary, transferred to the enlargement processing unit 4 via the memory unit 3.

As shown in FIG. 6, the enlargement processing unit 4 enlarges the image data read by the scanner unit 2 with a ratio R of the linear density La of the printer unit 10 and the linear density Lb of the scanner unit 2, and enlarges the image data. The processed image data is transferred to the edge determination unit 5, the gradation processing unit 9, and the edge enhancement unit 6 directly or via the memory unit 3. The edge determination unit 5 performs a convolution operation of the target pixel and the peripheral pixels using the matrix circuits 21a to 21d as shown in FIG. 2, sets the maximum absolute value thereof as the edge amount, and performs the edge determination. Then, the edge amount is output to the edge enhancement unit 6 and the determination result is output to the selector 8.

The gradation processing unit 9 also performs gradation processing on the image data expanded by the expansion processing unit 4 in accordance with the characteristics of the printer unit 10, that is, the degree of gradation, and the image data subjected to gradation processing is selected by the selector 8. Output to.

Further, the edge emphasizing unit 6 calculates the edge emphasizing coefficients 26a, 2a based on the edge amount from the edge judging unit 5.
6b and the selected edge enhancement coefficient 26
The edge enhancement processing is performed with a and 26b, and the image data subjected to the edge enhancement processing is output to the selector 8. That is,
The edge emphasizing unit 6 selects either the strong edge emphasizing coefficient 26a or the weak edge emphasizing coefficient 26b based on the edge amount input from the edge determining unit 5, and expands the selected edge emphasizing coefficient 26a, 26b. The edge enhancement processing is performed by multiplying the image data subjected to the enlargement processing of the processing unit 4, and the image data subjected to the edge enhancement processing is selected by the selector 8
Output to.

The selector 8 selects either the image data input from the gradation processing unit 9 or the image data input from the edge enhancement unit 6 based on the determination result input from the edge determination unit 5, The selected image data is transferred to the printer unit 10 directly or via the memory unit 3.
That is, when the edge determination unit 5 determines that the edge determination unit 5 is the edge unit, the selector 8 selects the image data output by the edge enhancement unit 6 and outputs the image data to the printer unit 10, and the edge determination unit 5 is not the edge unit. If determined, the image data output by the gradation processing unit 9 is selected and output to the printer unit 10.

Similarly to the above, the printer section 10 records and outputs an image on a recording sheet based on the image data transferred from the selector 8.

As described above, after the image data read by the scanner 2 having a low linear density is enlarged according to the linear density of the printer unit 10, gradation processing is performed according to the characteristic (gradation degree) of the printer unit 10. At the same time, since the edge emphasis processing is performed, the printer unit 10 can perform recording with the same image quality as when the image is read using the scanner unit 2 having a high linear density, and the edges such as characters and thin lines are emphasized. It is possible to record and output, and it is possible to record a high-quality image by the inexpensive image processing apparatus 1 using the inexpensive scanner unit 2.

In the case of FIG. 6, only one edge emphasizing unit 6 is provided to select the edge emphasizing coefficients 26a and 26b. However, the edge emphasizing process is not limited to this method. As shown in FIG. 7, two edge enhancement units 31 and 32 may be provided, and each may have a different edge enhancement coefficient, for example, a strong edge enhancement coefficient 26a and a weak edge enhancement coefficient 26b. .

In this case, the edge emphasizing unit 31 performs the edge emphasizing process on the image data subjected to the enlarging process of the enlarging processing unit 4 by the strong edge emphasizing coefficient 26a, and outputs the image data to the selector 8. The edge enhancement coefficient 26b is used to perform edge enhancement processing on the image data subjected to the enlargement processing by the enlargement processing unit 4 and output the image data to the selector 8.

Then, the edge determination section 5 outputs the edge amount and the edge determination result to the selector 8, and the selector 8
Based on the edge determination result and the edge amount, it is determined whether the image data is an edge, the edge amount is determined, and the image data input from the gradation processing unit 5, the edge enhancing unit 31, and the edge enhancing unit 32. Decide which one to choose. That is, if the determination result indicates that it is not an edge, the selector 8 selects the image data input from the gradation processing unit 5 and outputs it to the printer unit 10.
If the determination result indicates that the edge is, the image data input from the edge enhancing unit 31 is input if the edge amount is larger than a predetermined amount, and is input from the edge enhancing unit 32 if the edge amount is smaller than the predetermined amount. The selected image data is output to the printer unit 10.

Therefore, also in this case, after the image data read by the scanner 2 having a low linear density is enlarged in accordance with the linear density of the printer unit 10, the floor is adjusted in accordance with the characteristic (gradation degree) of the printer unit 10. Since the adjustment processing and the edge enhancement processing are performed, the printer unit 10 can perform recording with the same image quality as when an image is read using the scanner unit 2 having a high linear density, and the edges such as characters and thin lines are removed. It is possible to emphasize and record and output, and it is possible to record a high-quality image by the inexpensive image processing apparatus 1 using the inexpensive scanner unit 2.

Next, a case in which enlargement processing, edge enhancement processing, smoothing processing and gradation processing corresponding to claim 2 are performed and recorded will be described below with reference to the processing explanatory diagram of FIG.

Under the control of the controller 11, the image processing apparatus 1 causes the scanner unit 2 to read the image of the document set on the scanner unit 2 at a predetermined linear density Lb in the same manner as described above.
The image data read by is directly or, if necessary, transferred to the enlargement processing unit 4 via the memory unit 3.

As shown in FIG. 8, the enlargement processing unit 4 enlarges the image data read by the scanner unit 2 with a ratio R of the linear density La of the printer unit 10 and the linear density Lb of the scanner unit 2, and enlarges the image data. The processed image data is transferred to the smoothing processing unit 7, the edge emphasizing unit 6, and the edge determination unit 5 directly or via the memory unit 3.

The edge determining section 5 performs a convolution operation of the target pixel and peripheral pixels using the matrix circuits 21a to 21d as shown in FIG. 2, and sets the maximum absolute value as the edge amount. , Edge determination is performed, the edge amount is output to the edge emphasizing unit 6, and the determination result is output to the selector 8.

The edge emphasizing unit 6 is the edge judging unit 6 of FIG.
Similarly, the edge enhancement coefficients 26a and 26b are selected based on the edge amount input from the edge determination unit 5, the edge enhancement processing is performed using the selected edge enhancement coefficients 26a and 26b, and the edge enhanced image data is displayed. Output to the selector 8. The edge enhancing unit 6 may include the edge enhancing units 31 and 32 shown in FIG. 7.

The smoothing processing section 7 uses the smoothing matrix coefficient 27 shown in FIG. 4 to perform a convolution operation with the peripheral pixels of the input target pixel to perform smoothing processing, It is output to the adjustment processing unit 9.

The gradation processing unit 9 performs gradation processing on the smoothed image data of the smoothing processing unit 7 according to the gradation of the printer unit 10, and outputs the gradation-processed image data to the selector 8.

The selector 8 selects either the image data input from the gradation processing unit 9 or the image data input from the edge enhancement unit 6 based on the determination result input from the edge determination unit 5. The selected image data is transferred to the printer unit 10 directly or via the memory unit 3. That is, when the edge determination unit 5 determines that the edge determination unit 5 is the edge unit, the selector 8 selects the image data output by the edge enhancement unit 6 and outputs the image data to the printer unit 10, and the edge determination unit 5 is not the edge unit. If judged, the gradation processing unit 9
The image data to be output is selected and output to the printer unit 10.

Similarly to the above, the printer section 10 records and outputs an image on a recording sheet based on the image data transferred from the selector 8.

As described above, after the image data read by the scanner 2 having a low linear density is enlarged to the linear density of the printer unit 10, the edge portion such as a character or a thin line portion is subjected to the edge emphasis processing and is not processed. For the edge part,
After the smoothing process, the gradation process is performed in accordance with the characteristics (gradation degree) of the printer unit 10. Therefore, the reproducibility can be improved for characters and thin line parts, and smooth for patterns and photographic images. It can be reproduced with various gradations. As a result, an image of higher quality can be recorded by the inexpensive image processing device 1 using the inexpensive scanner unit 2.

Although the invention made by the present inventor has been specifically described based on the preferred embodiments, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the scope of the invention. It goes without saying that it can be changed.

For example, in the above embodiment, the edge enhancement unit 6 is provided with two types of edge enhancement coefficients 26a and 26b to perform strong and weak edge enhancement, but it is provided with two or more types of edge enhancement coefficients. May be.

[0068]

According to the image processing apparatus of the present invention, the image data read by the image reading means having a low resolution can be enlarged and gradation processed in accordance with the recording means having a high resolution. It is possible to record an image of high quality similar to the case where the image is read by the high-resolution reading unit and is recorded by the high-resolution recording unit by using the image reading unit.

According to the image processing apparatus of the present invention, the image data read by the image reading means having a low resolution is enlarged in accordance with the recording means having a high resolution, and the edge portion of the image is subjected to the edge enhancement processing. For the non-edge portion of the image, gradation processing can be performed, and the reproducibility of characters and thin lines of the image read by using an inexpensive image reading unit is improved to obtain a higher quality image. Can be recorded.

According to the image processing apparatus of the present invention, the image data read by the low-resolution image reading means is enlarged in accordance with the high-resolution recording means, and the edge portion of the image is subjected to edge enhancement processing. The non-edge part of the image can be subjected to the gradation process after the smoothing process, and the reproducibility of characters and thin lines can be improved by using the inexpensive image reading means, and the pattern can be improved. It is possible to improve the reproducibility of images of photographs and photographs. As a result, it is possible to record a higher quality image by using the inexpensive image reading means.

According to the image processing apparatus of the present invention, the edge strength can also be determined and the edge enhancement processing can be performed in correspondence with the edge strength, so that the reproducibility of characters, thin lines, and the like can be further optimized. Can be reproduced.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an image processing apparatus to which an embodiment of an image processing apparatus of the present invention is applied.

FIG. 2 is a circuit configuration diagram of an edge determination unit in FIG.

FIG. 3 is a diagram showing an example of a strong edge enhancement coefficient (a) and a weak edge enhancement coefficient (b) used in the edge enhancement unit of FIG.

FIG. 4 is a diagram showing an example of a smoothing matrix coefficient used in the smoothing processing unit in FIG.

FIG. 5 is a process explanatory diagram of a case where only enlargement processing and gradation processing are performed for recording.

FIG. 6 is an explanatory diagram of processing when performing enlargement processing, gradation processing, and edge enhancement processing for recording.

FIG. 7 is an explanatory diagram of processing when two edge emphasis units of FIG. 6 are provided.

FIG. 8 is a process explanatory diagram of a case where an enlargement process, an edge enhancement process, a gradation process, and a smoothing process are performed for recording.

[Explanation of symbols]

1 Image processing device 2 Scanner section 3 memory section 4 Enlargement processing section 5 Edge determination section 6 Edge emphasis section 7 Smoothing processing section 8 selector 9 gradation processing unit 10 Printer section 11 Controller 12 buses

Claims (3)

(57) [Claims] 1. An image reading means for reading an image of a document at a predetermined linear density and outputting it as image data, and an image is recorded at a predetermined gradation and a linear density higher than the linear density of the image reading means. Recording means for recording and outputting on paper, enlarging processing means for enlarging the image data read by the image reading means according to the linear density of the recording means, and edge of the image of the image data enlarged by the enlarging processing means. Edge determination means for determining the image data, edge enhancement processing means for performing edge enhancement processing on the enlarged image data of the enlargement processing means, and the enlarged image data of the enlargement processing means in accordance with the gradation degree of the recording means. Gradation processing means for converting the number of gradations, the image data with the edge enhancement performed by the edge enhancement processing means based on the determination result of the edge determination means, and the gradation processing means. Comprising selecting means for selecting and converted the image data, the image processing apparatus and recording outputs the image data selected in the selecting means by said recording means. 2. An image reading means for reading an image of a document at a predetermined linear density and outputting it as image data, and an image is recorded at a predetermined gradation degree and at a linear density higher than the linear density of the image reading means. Recording means for recording and outputting on paper, enlarging processing means for enlarging the image data read by the image reading means according to the linear density of the recording means, and edge of the image of the image data enlarged by the enlarging processing means. Edge determining means for determining whether the enlarged image data is enlarged by the enlargement processing means, and smoothing processing means for performing smoothing processing on the enlarged image data by the enlargement processing means. And a gradation processing means for converting the number of gradations of the image data smoothed by the smoothing processing means according to the gradation degree of the recording means, and a judgment result of the edge judging means. Selection means for selecting the image data subjected to edge enhancement by the edge enhancement processing means and the image data converted by the gradation processing means on the basis of the image data selected by the selection means. An image processing apparatus characterized by recording and outputting by means of. 3. The edge determination means also determines the edge strength of the image data, and the edge emphasis processing means
It said edge determination means determines the image processing apparatus according to claim 1 or claim 2, wherein by changing the degree of the edge emphasis and performing edge enhancement processing based on the intensity of the edge.