JPH01106578A - Method for setting picture processing data - Google Patents

Abstract

PURPOSE:To make the picture quality of pictures uniform by correcting a standard sharpness parameter set by an operator in accordance with other output conditions by using a correction table. CONSTITUTION:Corrected sharpness parameters which are determined by the relation between sharpness parameters set by an operator and output conditions of picture magnification, etc., are prepared as a correction table 34. By using the correction table 34, the sharpness parameters K set by the operator are reset in accordance with the other output conditions. Since the operator can reset the sharpness parameters K without considering the output conditions, such as picture magnification, etc., at the time of resetting, any troubles, such as occurrence of wrong setting of the parameters K, decline in the quality of reproduced pictures caused by the selection of different parameters due to individual differences among operators, can be eliminated. Therefore, the work of the operator can be reduced and pictures of a stable picture quality can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for setting image processing data, and more particularly, a method for setting sharpness parameters in an image reproducing device, which is set by an operator. The present invention relates to a method of setting image processing data that makes it possible to generate an image of stable quality by resetting the sharpness parameter using a correction table based on the sharpness parameter and output conditions such as the magnification of the reproduced image.

[Background of the Invention] For example, in the fields of printing and plate making, image scanning, reading and reproducing is used to electrically process image information carried on a manuscript to create a film master plate for the purpose of streamlining work processes, improving image quality, etc. The system is being used illegally.

This system basically consists of an image reading section and an image reproducing section, and in the image reading section, image information carried on a document being conveyed in a sub-scan direction is scanned by an optical sensor and converted into an electrical signal. . Next, the image information photoelectrically converted in the image reading section is subjected to image processing according to the plate-making conditions in the image reproduction section, and then converted into an optical signal such as a laser beam, and is recorded as an image made of a photosensitive material such as a film. recorded on a carrier. The image recording carrier is developed by a predetermined developing device and used as a film original for printing or the like.

In such an image scanning reading and reproducing system, when reproducing a desired image according to the plate-making conditions, image magnification, screen line count, output mode (yI point image, character line drawing, etc.), sharpness parameters, etc. It is necessary to set output conditions such as Here, the number of screen lines is 1
This is the number of halftone dots included per inch, and is a parameter representing the roughness of the reproduced image when the output mode is a halftone image. Further, the sharpness parameter is a parameter that determines the degree to which the outline of the reproduced image is emphasized. The operator selects a predetermined output condition from among these output conditions and manually inputs and sets the output condition using a keyboard or the like.

By the way, among such output conditions, the sharpness parameter is closely related to other output conditions such as image magnification and screen line number. For example, if the image magnification is changed while the sharpness parameter is fixed, the actual sharpness strength of the reproduced image changes depending on the image magnification.

Further, the sharpness strength of a reproduced image generally changes not only depending on the image magnification but also on other output conditions such as the number of screen lines and the output mode. Therefore, the operator must set the sharpness parameter after considering the relationship between each output condition. As a result, it has been pointed out that errors in setting sharpness parameters are likely to occur, and selection of output conditions differs depending on individual differences among operators, resulting in unstable reproduced image quality.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and includes creating a correction table of sharpness parameters for output conditions such as image magnification in advance, and adjusting the standard sharpness set by the operator. To provide an image processing data setting method that facilitates sharpness parameter setting work and promotes uniformity of image quality by correcting parameters according to other output conditions using the correction table. With the goal.

[Means for Achieving the Object] In order to achieve the above object, the present invention provides a standard for performing sharpness correction on a reference reproduced image when reproducing an image based on output conditions such as sharpness parameters and image magnification. A correction sharpness parameter set based on the relationship between the sharpness parameter and output conditions such as image magnification is created as a correction table, and a desired correction sharpness parameter is determined based on the correction table from the reference sharpness parameter and output conditions such as image magnification. It is characterized by setting.

[Embodiments] Next, preferred embodiments of the image processing data setting method according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates an image scanning, reading and reproducing system to which the image processing data setting method according to the present embodiment is applied. It basically consists of.

The image reading unit 12 has a line sensor 18 such as a CCD that converts optical signals into electrical signals.
Image information is read by main scanning through 0. The image processing section 14 includes an A/D converter 22 that converts an analog signal from the line sensor 18 into a digital signal, a sharpness correction section 24 that performs sharpness correction on the image signal that is the digital signal according to output conditions, and and a D/A converter 26 that converts the signal into an analog signal. Note that the image processing section 14 performs gradation correction, halftone dot repair, etc. of the image signal as necessary. In addition, the image reproduction section 16
is a laser output unit 28 that outputs laser light, an acousto-optic modulator 30 that modulates the intensity of the laser light, and an analog signal output from the D/A converter 26 of the image processing unit 14. A driver 32 driven based on
including. In this case, the laser light is transmitted through the acousto-optic modulator 30.
Image information is reproduced on the film F by main-scanning the film F, which is conveyed in the sub-scanning direction.

Here, the sharpness correction section 2 in the image processing section 14
4 basically consists of a sharpness parameter correction table 34 and a sharpness emphasis circuit 36, as shown in FIG. In this case, the correction table 34 includes image magnification, screen line number, and
Mask size data and corrected sharpness parameters are output to the sharpness enhancement circuit 36 based on output conditions such as output mode and sharpness parameters.

Note that the mask size data is data corresponding to the type of blur mask used when optically correcting the sharpness of an image signal, and corresponds to the number of pixels of an image signal for generating an unsharp signal, which will be described later.

The sharpness enhancement circuit 36 performs sharpness correction on the image signal based on the mask size data and the corrected sharpness parameters. In this case, A/D
The image signal output from the converter 22 is supplied to a multiplier 38, while being supplied to an unsharp signal generator 40,
The signal is converted into an unsharp signal based on the mask size data and supplied to the multiplier 42 . Further, the corrected sharpness parameter output from the correction table 34 is supplied to a multiplier 42, and the adder 44 adds +1 to the sharpness parameter, and the resulting sharpness parameter is supplied to a multiplier 38. Further, the output signal from the multiplier 38 is supplied to a subtracter 46, in which the output signal from the multiplier 42 is subtracted, and the resulting signal is supplied to the D/A converter 26 as a sharpness-corrected image signal. .

The apparatus for carrying out the image processing data setting method according to this embodiment is basically configured as described above, and the operation thereof and the image processing data setting method will be explained next.

First, in the image reading section 12, image information carried on the original S is photoelectrically read through a condensing lens 20 by a line sensor 18 consisting of a photoelectric conversion element such as a COD. In this case, the document S is conveyed in the sub-scanning direction by a conveyance mechanism (not shown), and is main-scanned by the line sensor 18, thereby reading the image information carried on the entire surface. Next, the image information photoelectrically converted by the line sensor 18 is converted into an image signal as a digital signal by the A/D converter 22 in the image processing section 14, and then supplied to the sharpness correction section 24.

Here, the sharpness correction section 24 performs sharpness correction of the image signal according to the procedure shown in FIG. That is,
Assuming that the image signal obtained from the original S is divided into nXn pixels, first, the image signal 5tj (i=1'-
An unsharp signal U , which is an electrically blurred image signal, is created from the image signal S ij (n, j = 1”·n). This unsharp signal U 4 j is created by averaging the image signals surrounding the image signal S ij. In equation (1), M is the number of pixels used to create the unsharp signal U!4, that is, mask size data, and L is (M- 1
)/2. Next, a difference signal between the image signal S ij and the unsharp signal U ij is obtained. Then, by multiplying this difference signal by the sharpness parameter K and adding the image signal Sij, S゛th=S,j0K・(SiJ−Uij)...
An image signal S' ij defined by (2) is obtained. In this case, the image signal S' i j is the image signal S before sharpness correction, as shown in FIG.
The signal is converted into a signal with the edge portion emphasized compared to ij.

Next, the sharpness correction method described above will be specifically explained based on FIG. In this case, the correction table 34 for obtaining the new corrected sharpness parameter K is prepared in advance in the fourth
Set it as shown in the figure. Note that this correction table 34
To simplify the explanation, is a table corresponding to the sharpness parameter determined by the combination of the reference sharpness parameter and image magnification for the reference reproduction image input by the operator, and the mask size data M obtained from this correction table. is assumed to be constant.

Therefore, the operator manually inputs output conditions such as image magnification, screen line number, output mode, reference sharpness parameter, etc. to the image processing unit 14 according to the plate-making conditions. In this case, the operator only needs to select a standard sharpness parameter for making the standard reproduced image with a fixed image magnification a desired sharpness level, and there is no need to consider the influence of the image magnification. The correction table 34 outputs the sharpness parameter corrected based on the reference sharpness parameter and image magnification input by the operator and the mask size data M to the sharpness emphasis circuit 36.

The mask size data M may be set by the operator, or may be obtained from the correction table 34 in the same way as the sharpness parameter.

The sharpness emphasis circuit 36 is the unsharp signal generator 4
0, an unsharp signal U i is obtained from the image signal S i j and the mask size data M based on equation (1).
j and supplies it to the multiplier 42.

In this case, the corrected sharpness parameter K is supplied to the multiplier 42 from the correction table 34. Therefore, the multiplier 42 provides the subtracter 46 with K-U as an output signal. The subtracter 46 also receives the signal (1+K) supplied via the adder 44 in the multiplier 38 and the image signal S! multiplied by j (1+K)
- S i j signals are supplied. As a result, subtractor 4
6 is the sharpness-corrected image signal S'! expressed by equation (2). Outputs 1.

Therefore, the image signal S' outputted from the sharpness correction section 24 is converted into an analog signal by the D/A converter 26 and supplied to the driver 32.

On the other hand, in the image reproduction section 16, the laser beam output from the laser output section 28 is modulated according to image information by an acousto-optic modulator 30 driven by a driver 32, and is irradiated onto the film F. In this case, the film F is being conveyed in the sub-scanning direction, and image information according to the output conditions is reproduced on the entire surface thereof. Note that this film F is developed into a visible image by a developing device.

[Effects of the Invention] As described above, according to the present invention, a corrected sharpness variation determined by the relationship between the sharpness parameter set by the operator and output conditions such as image magnification is created as a correction table, and this Using a correction table, the sharpness parameter set by the operator is reset in accordance with other output conditions.

In this case, the operator can set sharpness parameters without considering output conditions such as image magnification, which may result in errors in setting sharpness parameters.
Alternatively, by selecting different sharpness parameters depending on individual differences among operators, the inconvenience of deterioration in the quality of reproduced images can be eliminated. As a result, the operator's work is reduced, and images with stable quality can be obtained.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
For example, it is possible to create a correction table that takes into account the number of screen lines, output mode, mode, etc. as a correction table for sharpness parameters, and various improvements and design changes can be made without departing from the gist of the present invention. Of course it is possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an image scanning reading/reproducing system to which the method of the present invention is applied. FIG. 2 is a block diagram of the configuration of the sharpness correction section shown in FIG. 1. FIG. 3 is an explanation of sharpness correction in the method of the present invention. FIG. 4 is an explanatory diagram of a sharpness parameter correction table created in the method of the present invention. 10... Image scanning reading/reproducing system 12... Image reading section ``'' 14... Image processing section 16... Image reproducing section 18... Line sensor 24... Sharpness correction section 28...
Laser output section 34...Correction table 36...Sharpness emphasis circuit F...Film L
...Laser light S...Manuscript FIG, 4

Claims (1)

[Claims] (1) When reproducing an image based on output conditions such as sharpness parameters and image magnification, sharpness correction is performed on the standard reproduced image. Corrected sharpness that is set in relation to the standard sharpness parameter and output conditions such as image magnification. A method for setting image processing data, characterized in that parameters are created as a correction table, and a desired correction sharpness parameter is set based on the correction table from a reference sharpness parameter and output conditions such as image magnification.