JPH10200734A - Image processing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the image processing unit not causing a glanularity problem (a phenomenon that particulates are enlarged and reproduced on an magnified image when resolution is increased in the case of reading an original in which the opaque particulates whose shape and size are ununiform (so-called silver particulates) are irregularly dispersed) even when the original is magnified in the image processing. SOLUTION: Prior to image processing, the operator sets and enters a final magnification with respect to an original. Then a magnification decision section 90 decides a read magnification of an image input section 30 and a magnification for a magnification conversion processing section 70 based on the final magnification. In this case, the magnification decision section 90 decides a read magnification to be within a range of magnification not to read particulates of the original. Then the image input section 30 reads the original according to the decided read magnification and an image processing section 80 applies image processing such as contour emphasis processing to the read image and then the magnification conversion processing section 70 executes the magnification conversion processing according to the decided magnification.

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 for performing predetermined image processing including enlargement processing on an image obtained by reading a document.

[0002]

2. Description of the Related Art Generally, an image processing apparatus optically reads an original with an input scanner or the like, converts the read analog signal into a digital signal, and performs image processing such as contour enhancement processing and noise removal processing. The image is output as a film or plate from an output device, and a series of image processing is performed.

There is a case where it is desired to enlarge a document in the above-described image processing. In such a case, conventionally, in such a case, the resolution at the time of reading the document is increased (the reading magnification is increased) to enlarge the image. The magnification was improved.

[0004] In addition, contour enhancement processing performed on an image generated from a read original is performed to enhance a contour portion such as a pattern in the image and to sharpen the pattern. FIG. 5 is a diagram for explaining the outline emphasis processing. In this figure, the horizontal axis indicates the pixel position, and the vertical axis indicates the level of the pixel signal.

[0005] As shown in the figure, the main signal S of an image has high and low levels, that is, shading, depending on the pixel position. In the contour enhancement processing, first, the image is scanned with a filter composed of a local pixel group (for example, a 3 × 3 pixel matrix), and a weighted average of the signal values in the local pixel group is calculated. Obtain signal U. Then, from the main signal S to the unsharp signal U
Is subtracted to calculate an unsharp mask signal (SU) serving as a basic signal for contour enhancement. Thereafter, the unsharp mask signal (SU) is multiplied by an intensity coefficient k for contour enhancement to obtain a contour enhanced signal k (SU).
By adding (SU) to the original main signal S, an edge-enhanced signal (S + k (SU)) is obtained.

[0006]

By the way, in the above-mentioned conventional image processing apparatus, a fine pattern can be reproduced by increasing the resolution at the time of reading a document, but the following problems also occur. That is, fine particles (so-called silver particles) that are opaque and are not uniform in size and shape are irregularly dispersed in the original, and when the resolution at the time of reading the original is increased, the fine particles are enlarged and reproduced on the image. In other words, a so-called graininess problem may occur. When such a problem occurs, the quality of the image naturally deteriorates.

As a result of the outline emphasis processing, the portion represented by the length "d" shown in FIG. 5 becomes the width of the outline portion where the outline is emphasized (hereinafter, referred to as "edge width"). In some cases, it is necessary to increase the edge width depending on the type of the image or the background, and particularly when the document is enlarged and read, it is often necessary to increase the edge width. Conventionally, when it is desired to increase the edge width, the size of a filter to be scanned at the time of contour enhancement processing is increased. That is, for example, by changing a 3 × 3 pixel matrix to a 5 × 5 pixel matrix, the edge width can be increased by about 5/3.

[0008] However, increasing the size of the filter increases the amount of calculation in the outline emphasis processing, and as a result, a reduction in processing speed is inevitable.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an image processing apparatus which does not cause a problem of graininess even when it is desired to enlarge a document in image processing.

Another object of the present invention is to provide an image processing apparatus capable of adjusting the width of a contour portion after the contour enhancement processing without lowering the processing speed when performing the contour enhancement processing. .

[0011]

According to a first aspect of the present invention, there is provided an image processing apparatus for performing predetermined image processing including enlargement processing on an image obtained by reading a document. a) an original reading means for optically reading the original with a variable magnification and generating an image signal of the original; and (b) a predetermined method for an image represented by the image signal obtained by the original reading means. Image processing means for performing image processing; and (c) magnification conversion processing means for performing magnification conversion processing on the image after the predetermined image processing.

According to a second aspect of the present invention, in the image processing apparatus according to the first aspect of the present invention, there is provided: (d) setting input means for setting and inputting a final magnification for the original; And magnification determining means for determining a magnification in the document reading means based on the magnification.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an image processing apparatus 100 according to the present invention.
FIG. 2 is a block diagram showing an electrical configuration of the embodiment. The image processing apparatus 100 includes a control unit 50, an operation unit 10, a display unit 20
, An image input unit 30 and an image output unit 40.

The operation unit 10 is a means for an operator to give an instruction to the image processing apparatus 100, and comprises a keyboard and a mouse. As will be described later, the operation unit 10 also has a function as a set value input unit for inputting the set value of the final magnification and the set value of the reading magnification. The display unit 20 is a display on which an operator can confirm an image to be processed and a message from the control unit 50. Further, the image input unit 30
Reads the document to be processed at a variable magnification,
The image output unit 40 is an input unit (an output scanner, an image setter, or the like) for outputting a processed image.

In the above-described image processing apparatus 100, the operator gives an appropriate command to the control unit 50 via the operation unit 10 so that the image input from the image input unit 30 can be subjected to a magnification conversion process and a contour Emphasis processing can be performed. Then, the operator can visually confirm the processing result on the display unit 20 and can confirm the final output result by outputting the processing result from the image output unit 40.

The control unit 50 is a processing unit that performs a magnification conversion process, an outline emphasis process, and the like, and includes an image storage unit 60, a magnification conversion processing unit 70, an image processing unit 80, and a magnification determination unit 90. I have. The image storage unit 60 is a RAM that stores an image processing program and an image signal. It should be noted that a magnetic disk or the like may be connected to the image storage unit 60 so that programs and data are read from the magnetic disk.

The magnification conversion processing section 70 is a processing section for performing magnification conversion on an image, and the image processing section 80 is a processing section for performing contour enhancement processing and noise removal processing. The magnification determining unit 90 is a processing unit that determines a conversion magnification executed in the magnification conversion processing unit 70. The processing contents of each of these processing units will be further described later.

FIG. 2 is a diagram schematically showing a configuration of a main part of the image input unit 30. As shown in FIG. The document 1 is placed on the document table 31. Then, the light emitted from the light source 32 passes through the original 1 and the original table 31, is reflected by the mirror 33, and enters the lens 34. This lens 34
Forms an image of the original 1 on the reading surface of the CCD 35.
The CCD 35 converts the image of the document 1 into electric charges and accumulates them, and generates an analog signal of the image. The generated analog signal is converted into a digital signal by A / D conversion means (not shown) and transferred to the control unit 50 of the image processing apparatus 100.

Here, the original table 31 is provided with a driving means 36 for moving the original table 31. By lowering the moving speed of the document table 31, the sampling of the document 1 by the CCD 35 can be subdivided, and as a result, the reading magnification of the image input unit 30 can be increased.

The method of changing the reading magnification is not limited to the above method. For example, the image input unit 30
, The lens 34 and the CCD 35 are also provided with driving means 37 and driving means 38, respectively, so that the distance between the original 1 and the lens 34 and the distance between the lens 34 and the CCD 3
5 can be adjusted. The reading magnification can be changed by adjusting these intervals. Further, the reading magnification may be changed by configuring the lens 34 with a zoom lens, and other known magnification conversion means may be employed.

Next, an image processing procedure in the image processing apparatus 100 will be described. FIG. 3 is a flowchart for explaining an image processing procedure in the image processing apparatus 100.

First, prior to image processing, a final magnification is set (step S1). The final magnification is a magnification of an image finally desired for the original 1 to be read, and is set and input by the operator via the operation unit 10. Next, the reading magnification in the image input unit 30 is determined (Step S2). The reading magnification refers to the image input unit 3 as described above.
The reading magnification of the original at 0, which is determined by the magnification determining unit 90 based on the final magnification.

FIG. 4 is a diagram for explaining how the reading magnification is determined based on the final magnification. As shown
When the final magnification set and input is relatively low (less than 10 times here), the reading magnification is determined so as to be proportional to the final magnification, while the final magnification input and set is relatively high ( In this case, the reading magnification is determined to be lower than the final magnification. This is because if the reading magnification is increased, the image input unit 30 reads the fine particles on the document 1 and causes a problem of graininess. Therefore, the maximum value of the reading magnification is determined within a range that does not cause the problem of graininess. Is done. To determine the reading magnification, specifically, the magnification determining section 90 is provided with a look-up table as shown in FIG. 4, and the magnification determining section 90 refers to the look-up table to set and input the final magnification. Execute based on Further, the contents of the look-up table are not limited to those shown in FIG. 4, but must determine the reading magnification within a range that does not cause a problem of graininess.

Returning to FIG. 3, the process proceeds to step S3, where the magnification determining section 90 determines the magnification in the magnification conversion processing section 70. Here, the magnification in the magnification conversion processing unit 70 is determined based on the final magnification and the reading magnification.
That is, the result of dividing the final magnification by the reading magnification is determined as the magnification in the magnification conversion processing unit 70.

As a specific example of the above-described magnification determining procedure, when the operator sets and inputs 20 times as the final magnification, the magnification determining section 90 reads the data while referring to the lookup table shown in FIG. The magnification is determined to be 13.3 times. Then, the magnification determining unit 90 determines the magnification in the magnification conversion processing unit 70 to be 1.5 times based on the final magnification and the reading magnification.

Next, the process proceeds to step S4, where the image input unit 30 reads the document 1 in accordance with the determined reading magnification. The reading by the image input unit 30 is performed according to the method described with reference to FIG. Then, the analog signal of the document 1 read at the reading magnification is converted into a digital signal, transferred to the control unit 50 of the image processing apparatus 100, and stored in the image storage unit 60.

Then, the process proceeds to a step S5, wherein the image processing section 80 performs an outline emphasizing process. The content of the outline emphasis processing is as described with reference to FIG.
The signal of the image stored in 0 is the main signal S. Note that the local pixel group constituting the filter for obtaining the unsharp signal U may be fixed to a 3 × 3 pixel matrix. In step S5, the image processing unit 80 may perform general image processing such as noise removal processing in addition to contour enhancement processing.

As a result of the outline emphasis processing, an edge width (length "d" shown in FIG. 5) corresponding to a filter composed of a 3 × 3 pixel matrix is formed. Since this edge width is a value determined by the size of the filter, it is substantially constant as long as a filter composed of a 3 × 3 pixel matrix is used.

Returning to FIG. 3, next, the process proceeds to step S6, in which the magnification conversion processing unit 70 executes the magnification conversion processing on the image after the contour enhancement processing in accordance with the magnification determined in step S3. Here, the magnification conversion processing is
This is a process of enlarging or reducing the size of an image by increasing or decreasing the total number of pixels of the image. Specifically, in the case of the enlarging process, the number of pixels is increased by interpolating pixel signals, and In the case of (1), the number of pixels is reduced by thinning out pixel signals. For example, when the magnification is 1.5, the number of pixels in the vertical and horizontal directions of the image is multiplied by 1.5, and the signal of the increased pixel is obtained by interpolating the signal of the pixel before enlargement. It is obtained by doing. At this time, the edge width after the outline emphasis processing is also scaled according to the scale determined in step S3. If the scale is 1.5 times, the edge width is also scaled by 1.5 times. Becomes

Finally, the process proceeds to step S7, in which the image subjected to the image processing is output to a plate or a film by the image output unit 40, and a series of processes is completed.

As described above, the reading by the image input unit 30 is performed at a magnification within a range where the particles of the document 1 are not read, and after the read image is subjected to the contour emphasis processing and the like, the magnification conversion processing is performed. Therefore, the problem of graininess can be avoided even when it is desired to enlarge the document.

The width of the outline after the outline emphasis processing is
Since the adjustment is made in accordance with the magnification in the magnification conversion processing unit 70, the width of the contour portion can be adjusted while keeping the size of the filter constant, that is, without increasing the amount of calculation, thereby preventing a reduction in processing speed. it can.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.
For example, in the above embodiment, the reading magnification is determined based on the final magnification. However, the operator directly sets and inputs the reading magnification via the operation unit 10 (for example, when the final magnification is set to 20 times). If the reading magnification is 1
(Set to 0 times). By doing so, the reading speed is directly set, so that the processing speed is improved. At this time, the operator needs to set the reading magnification in consideration of the balance between the range in which the problem of graininess does not occur and the quality of the image to be obtained.

[0035]

As described above, according to the first aspect of the present invention, the original is obtained by the original reading means for optically reading the original at a variable magnification to generate an image signal of the original, and the original reading means. Document reading means includes image processing means for performing predetermined image processing on an image represented by an image signal, and magnification conversion processing means for performing magnification conversion processing on an image after predetermined image processing. If the magnification at is set within a range where the particles of the document are not read, the document can be enlarged without causing the problem of graininess.
Furthermore, when the contour enhancement processing is performed during the predetermined image processing, the width of the processed contour part is adjusted by the magnification in the magnification conversion processing means, so that the amount of calculation does not increase. The width of the contour part can be adjusted without reducing the speed.

According to the second aspect of the present invention, there is further provided a setting input means for setting and inputting a final magnification for a document, and a magnification determining means for determining a magnification in the document reading means based on the final magnification. Therefore, the same effect as that of the first aspect can be easily obtained only by setting and inputting the final magnification for the document.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of an image processing apparatus according to the present invention.

FIG. 2 is a diagram schematically illustrating a configuration of a main part of an image input unit in FIG. 1;

FIG. 3 is a flowchart for explaining an image processing procedure in the image processing apparatus of FIG. 1;

FIG. 4 is a diagram for explaining how a reading magnification is determined based on a final magnification.

FIG. 5 is a diagram for explaining contour enhancement processing.

[Description of Signs] 10 Operation unit 30 Image input unit 70 Magnification conversion processing unit 80 Image processing unit 90 Magnification determination unit 100 Image processing device

Claims (2)

[Claims] 1. An image processing apparatus for performing predetermined image processing including enlargement processing on an image obtained by reading a document, comprising: (a) optically reading the document at a variable magnification; (B) image processing means for performing predetermined image processing on an image represented by an image signal obtained by the document reading means, (c) the predetermined image An image processing apparatus comprising: a magnification conversion unit that performs a magnification conversion process on an image after processing. 2. The image processing apparatus according to claim 1, wherein: (d) a setting input unit for setting and inputting a final magnification for the document; and (e) a setting unit for the document reading unit based on the final magnification. An image processing apparatus further comprising: a magnification determining unit that determines a magnification.